Organic compound, organic light emitting diode including the same, and organic light emitting device including the same

文档序号：729307 发布日期：2021-04-20 浏览：12次中文

阅读说明：本技术 有机化合物、包含该有机化合物的有机发光二极管和有机发光装置 (Organic compound, organic light emitting diode including the same, and organic light emitting device including the same ) 是由尹大伟裴淑英申仁爱崔树娜崔东勋赵民柱尹芝媛于 2020-10-16 设计创作，主要内容包括：本公开涉及具有以下结构的有机化合物、包含所述有机化合物的有机发光二极管(OLED)和有机发光装置。所述有机化合物是具有p型部分和n-型部分的双极性化合物,并且具有高能级和用于OLED的发光层的适当能量带隙。当将所述有机化合物应用至所述发光层时,由于空穴和电子在EML中的整个区域上均匀地复合,因此OLED可以使其发光特性最大化。(The present disclosure relates to an organic compound having the following structure, an Organic Light Emitting Diode (OLED) and an organic light emitting device including the same. The organic compound is a bipolar compound having a p-type portion and an n-type portion, and has a high energy level and an appropriate energy band gap for a light emitting layer of the OLED. When the organic compound is applied to the emission layer, the OLED may maximize its emission characteristics since holes and electrons are uniformly recombined over the entire region in the EML.)

1. An organic compound having a structure of the following chemical formula 1:

[ chemical formula 1]

wherein R is₂And R₃Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, wherein when a and b are each independently an integer of 2 or more, R₂And R₃Each of which is the same as or different from each other; a and b are each independently the number of substituents, a is an integer of 0 to 3, b is an integer of 0 to 4; x and Y are each independently CR₄R₅，

Wherein R is₄And R₅Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, or R₄And R₅Form C₆-C₂₀Aromatic ring or C₃-C₂₀A heteroaromatic ring; m and n are each 0 or 1, wherein m + n is 1; z is S, O or NR₆And an

Wherein R is₆Selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group.

2. The organic compound of claim 1, wherein the fused heteroaromatic group is unsubstituted, selected from C₁-C₂₀Alkyl radical, C₆-C₂₀Aryl radical, C₃-C₂₀Heteroaryl groups and combinations thereof, or forms a spiro ring structure with the fluorene or xanthene ring.

3. The organic compound of claim 1, wherein the fused heteroaromatic group is selected from the group consisting of a carbazolyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety, and a phenoAn oxazinyl moiety.

4. The organic compound of claim 1, wherein the fused heteroaromatic group is unsubstituted or is selected from C₁-C₁₀Alkyl, phenyl, carbazolyl and combinations thereof, or forms a spiro ring structure with the xanthene ring, and R₄And R₅Each unsubstituted or substituted by C₁-C₁₀Alkyl, phenyl, and combinations thereof, or R₄And R₅A fluorene ring is formed.

5. The organic compound of claim 1, wherein Z is S.

6. An organic light emitting diode comprising:

a first electrode;

a second electrode facing the first electrode; and

a light emitting layer disposed between the first electrode and the second electrode,

wherein the light emitting layer includes an organic compound having a structure of the following chemical formula 1:

[ chemical formula 1]

7. An organic light-emitting diode according to claim 6 wherein the fused heteroaromatic group is unsubstituted, selected from C₁-C₂₀Alkyl radical, C₆-C₂₀Aryl radical, C₃-C₂₀Heteroaryl groups and combinations thereof, or forms a spiro ring structure with the fluorene or xanthene ring.

8. The organic light-emitting diode of claim 6, wherein the fused heteroaromatic group is selected from the group consisting of a carbazolyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety, and a thiopheneAn oxazinyl moiety.

9. An organic light-emitting diode according to claim 6 wherein the fused heteroaromatic group is unsubstituted or is selected from C₁-C₁₀Alkyl, phenyl and carbazolyl groups and combinations thereof, or form a spiro ring structure with the xanthene ring, and R₄And R₅Each unsubstituted or substituted by C₁-C₁₀Alkyl, phenyl, and combinations thereof, or R₄And R₅A fluorene ring is formed.

10. An organic light emitting device comprising:

a substrate; and

an organic light emitting diode according to any one of claims 6 to 9 disposed over the substrate.

Technical Field

The present disclosure relates to an organic compound, and more particularly, to an organic compound having improved light emitting characteristics, an organic light emitting diode and an organic light emitting device including the same.

Background

As display devices become larger, there is a need for flat panel display devices with lower space requirements. Among the flat panel display devices that are currently widely used, a display having an Organic Light Emitting Diode (OLED) is rapidly replacing a liquid crystal display device (LCD).

The OLED may be formed to have a thickness less thanAnd unidirectional or bidirectional images can be realized with the electrode configuration. In addition, the OLED may be formed on a flexible transparent substrate such as a plastic substrate, so that the OLED can easily realize a flexible or foldable display. Furthermore, the OLED can be driven at a lower voltage of 10V or less. In addition, the OLED has relatively low driving power consumption, and the color purity of the OLED is very high, compared to the plasma display panel and the inorganic electroluminescent device. In particular, OLEDs can realize red, green, and blue colors, and thus are attracting attention as light emitting devices.

In the OLED, holes injected from an anode and electrons injected from a cathode are recombined in the EML to form excitons, which are unstable excited states, and then light is emitted as the excitons are transferred to a stable ground state. Conventional fluorescent materials in which only singlet excitons participate in the light emitting process have low light emitting efficiency. Phosphorescent materials in which triplet excitons as well as singlet excitons participate in the light-emitting process have relatively high light-emitting efficiency. However, the luminescence lifetime of metal complexes (representative phosphorescent materials) is too short to be suitable for commercial devices. In particular, a light emitting material for realizing blue light emission has deteriorated light emission characteristics and light emission lifetime.

Disclosure of Invention

Accordingly, the present disclosure is directed to an organic compound and an OLED and an organic light emitting device including the same that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

Further, the present disclosure provides an organic compound having a high excited triplet level and a bipolar characteristic, an OLED and an organic light emitting device to which the organic compound is applied.

In addition, the present disclosure provides an organic compound having excellent thermal stability and high affinity for charges, an OLED and an organic light emitting device having the same.

Additional features and aspects will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the inventive concepts presented herein. Other features and aspects of the inventive concept may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other aspects of the present disclosure, as embodied and broadly described, the present disclosure provides an organic compound having a structure of the following chemical formula 1:

[ chemical formula 1]

Wherein R is₁Is an unsubstituted or substituted fused heteroaromatic radical having 3 to 6 aromatic or heteroaromatic rings and 1 to 3 nitrogen atoms, unsubstituted or substituted C₆-C₃₀Aromatic amino group, or unsubstituted or substituted C₄-C₃₀A heteroaromatic amino group; r₂And R₃Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, wherein when a and b are each independently an integer of 2 or more, R₂And R₃Each of which is the same as or different from each other; a and b are each independently the number of substituents, a is an integer of 0 (zero) to 3, b is an integer of 0 (zero) to 4; x and Y are each independently CR₄R₅Wherein R is₄And R₅Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substitutedC of (A)₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, or R₄And R₅Form C₆-C₂₀Aromatic ring or C₃-C₂₀A heteroaromatic ring; m and n are each 0 (zero) or 1, wherein m + n is 1; z is S, O or NR₆Wherein R is₆Is hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical, or unsubstituted or substituted C₃-C₃₀A heteroaromatic group.

In another aspect, the present disclosure provides an OLED comprising a first electrode; a second electrode facing the first electrode; and a light-emitting layer disposed between the first electrode and the second electrode, wherein the light-emitting layer contains the organic compound.

For example, at least one of an Electron Transport Layer (ETL), a Hole Blocking Layer (HBL), an Emitting Material Layer (EML), and a Charge Generation Layer (CGL) may include the organic compound.

As an example, the EML may include the organic compound as a host, and in this case, the EML may further include at least one dopant such as a delayed fluorescent material, a fluorescent material, and a phosphorescent material.

In yet another aspect, the present disclosure provides an organic light emitting device, such as an organic light emitting display device and an organic light emitting lighting device, including a substrate and the OLED as described above disposed over the substrate.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the inventive concepts claimed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this disclosure, illustrate aspects of the disclosure and together with the description serve to explain the principles of the disclosure.

In the drawings:

fig. 1 is a schematic cross-sectional view illustrating an organic light emitting display device according to an exemplary aspect of the present disclosure;

fig. 2 is a schematic cross-sectional view illustrating an OLED according to one exemplary aspect of the present disclosure;

FIG. 3 is a schematic diagram showing a light emission mechanism of a delayed fluorescent material;

fig. 4 is a schematic diagram illustrating a light emitting mechanism by an energy level bandgap between light emitting materials according to an exemplary aspect of the present disclosure;

fig. 5 is a schematic cross-sectional view illustrating an OLED according to another exemplary aspect of the present disclosure;

fig. 6 is a schematic diagram illustrating a light emitting mechanism by an energy level bandgap between light emitting materials according to another exemplary aspect of the present disclosure;

fig. 7 is a schematic cross-sectional view illustrating an OLED according to another exemplary aspect of the present disclosure;

fig. 8 is a schematic diagram illustrating a light emitting mechanism by an energy level bandgap between light emitting materials according to another exemplary aspect of the present disclosure;

fig. 9 is a schematic cross-sectional view illustrating an OLED according to another exemplary aspect of the present disclosure;

fig. 10 is a schematic diagram illustrating a light emitting mechanism by an energy level bandgap between light emitting materials according to another exemplary aspect of the present disclosure;

fig. 11 is a schematic cross-sectional view illustrating an OLED according to yet another exemplary aspect of the present disclosure;

fig. 12 is a schematic cross-sectional view illustrating an organic light emitting display device according to another exemplary aspect of the present disclosure;

fig. 13 is a schematic cross-sectional view illustrating an OLED according to yet another exemplary aspect of the present disclosure;

fig. 14 is a schematic cross-sectional view illustrating an organic light emitting display device according to still another exemplary aspect of the present disclosure;

fig. 15 is a schematic cross-sectional view illustrating an OLED according to yet another exemplary aspect of the present disclosure; and

fig. 16 is a schematic cross-sectional view illustrating an OLED according to still another exemplary aspect of the present disclosure.

Detailed Description

Reference will now be made in detail to the present aspects and examples of the disclosure, some examples of which are illustrated in the accompanying drawings.

[ organic Compound ]

An organic compound applied to an Organic Light Emitting Diode (OLED) should have excellent light emitting characteristics, high charge affinity, and characteristics that remain stable when the OLED is driven. In particular, the light emitting material applied to the diode is the most important factor determining the light emitting efficiency of the OLED. The light emitting material should have high quantum efficiency, large charge mobility, and sufficient energy levels relative to other materials applied in the same or adjacent layers. The organic compounds comprise a fused aromatic ring comprising a benzimidazole moiety with high electron affinity and a fused heteroaromatic ring or (hetero) aromatic amino group with high hole affinity. The organic compound according to the present disclosure may have the structure of the following chemical formula 1:

[ chemical formula 1]

In chemical formula 1, R₁Is an unsubstituted or substituted fused heteroaromatic radical having 3 to 6 aromatic or heteroaromatic rings and 1 to 3 nitrogen atoms, unsubstituted or substituted C₆-C₃₀Aromatic amino group, or unsubstituted or substituted C₄-C₃₀A heteroaromatic amino group; r₂And R₃Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, wherein when a and b are each independently an integer of 2 or more, R₂And R₃Each of which is the same as or different from each other; a and b are each independently the number of substituents, a is an integer of 0 (zero) to 3, b is an integer of 0 (zero) to 4; x and Y are each independently CR₄R₅Wherein R is₄And R₅Each independently selected from hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group, or R₄And R₅Form C₆-C₂₀Aromatic ring or C₃-C₂₀A heteroaromatic ring; m and n are each 0 (zero) or 1, wherein m + n is 1; z is S, O or NR₆Wherein R is₆Is hydrogen, unsubstituted or substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical, or unsubstituted or substituted C₃-C₃₀A heteroaromatic group.

As used herein, the term "unsubstituted" means that a hydrogen atom is attached, and in this case, hydrogen includes protium, deuterium, and tritium.

As used herein, substituents in the term "substituted" include, but are not limited to: unsubstituted or halogen-substituted C₁-C₂₀Alkyl, unsubstituted or halogen-substituted C₁-C₂₀Alkoxy, halogen, cyano, -CF₃Hydroxyl, carboxyl, carbonyl, amino, C₁-C₁₀Alkylamino radical, C₆-C₃₀Arylamino, C₃-C₃₀Heteroarylamino group, C₆-C₃₀Aryl radical, C₃-C₃₀Heteroaryl, nitro, hydrazyl, sulfonate, C₁-C₂₀Alkylsilyl group, C₆-C₃₀Arylsilyl and C₃-C₃₀A heteroaryl silyl group.

As used herein, the term "hetero" in, for example, "heteroaromatic ring," "heterocycloalkylene," "heteroarylene," "heteroarylalkylene," "heteroaryloxy," "heterocycloalkyl," "heteroaryl," "heteroarylalkyl," "heteroaryloxy," "heteroarylamino" means that at least one carbon atom, e.g., 1 to 5 carbon atoms, constituting an aromatic or alicyclic ring is substituted with at least one heteroatom selected from N, O, S, P and combinations thereof.

The central fused aromatic ring in the organic compound having the structure of chemical formula 1 includes a benzimidazole moiety having excellent affinity for electrons, and thus has n-type characteristics inducing electron injection and transport. In addition, the fused heteroaromatic ring or the (hetero) aromatic amino group connected to the central fused aromatic ring has excellent affinity for holes and thus has a p-type characteristic of inducing hole injection and transport. Therefore, the organic compound having the structure of chemical formula 1 has bipolar characteristics.

In one aspect, R₁The fused heteroaromatic radical of (A) is unsubstituted and is selected from C₁-C₂₀Alkyl radical, C₆-C₂₀Aryl radical, C₃-C₂₀Heteroaryl groups and combinations thereof, or forms a spiro ring structure with the fluorene or xanthene ring. In another aspect, R₁The fused heteroaromatic radical of (A) is unsubstituted and is selected from C₁-C₁₀Alkyl, phenyl, carbazolyl, and combinations thereof, or forms a spiro ring structure with the xanthene ring.

In one exemplary aspect, R₁The fused heteroaromatic group in (a) is selected from the group consisting of a carbazolyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety and a thiopheneAn oxazinyl moiety. For example, carbazolyl moieties, acridinyl moieties, dihydroacridinyl moieties, phenazinyl moieties and thiophenesThe oxazinyl moieties may each comprise carbazolyl, acridinyl, dihydroacridinyl, phenazinyl and phenazinyl moieties, each unfused or fused with (but not limited to) a benzene ring, furan ring, thiophene ring, indene ring and/or indole ringAn oxazine group.

By way of example, substitution to R₁C of (A)₆-C₃₀Aryl groups may include, but are not limited to, unfused or fused aryl groups, such as phenylBiphenyl, terphenyl, naphthyl, anthracenyl, pentalenyl, indenyl, indenoindenyl, heptalenyl, biphenylene, indacenyl, phenalenyl, phenanthrenyl, benzophenanthrenyl, dibenzophenanthrenyl, azulenyl, pyrenyl, fluoranthenyl, triphenylenyl, azulenyl, phenanthrenyl,A group selected from the group consisting of mesityl, tetraphenyl, heptadienyl, picenyl, pentacenyl, fluorenyl, indenofluorenyl and spirofluorenyl.

In another exemplary aspect, substituted to R₁C in (1)₃-C₃₀Heteroaryl groups may independently include, but are not limited to, unfused or fused heteroaryl groups, pyrrolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, tetrazinyl, imidazolyl, pyrazolyl, indolyl, isoindolyl, indazolyl, indolizinyl, pyrrolizinyl, carbazolyl, benzocarbazolyl, dibenzocarbazolyl, indocarbazolyl, indenocarbazolyl, benzofurocarbazolyl, benzothienocarbazolyl, carbolinyl, quinolinyl, isoquinolinyl, phthalazinyl, quinoxalinyl, cinnolinyl, quinazolinyl, quinolizinyl, purinyl, benzoquinolinyl, benzoisoquinolinyl, benzoquinazolinyl, benzoquinoxalinyl, acridinyl, phenazinyl, phenoxazinyl, benzoxazinyl, benzoquinoxalinyl, benzoxazinyl, and benzoxazinyl groupsOxazinyl, phenothiazinyl, phenanthrolinyl, pyridyl (perimidinyl), phenanthridinyl, pteridinyl, naphthyridinyl, furyl, pyranyl, and the like,An oxazine group,Azolyl group,Oxadiazolyl, triazolyl, oxadiazolylAn indenyl group, a benzofuranyl group, a dibenzofuranyl group, a thiofuranyl group, a xanthenyl group, a chromenyl group (chromenyl group), an isochromenyl group, a thiazinyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, a difuranopyrazinyl group, a benzofurodibenzofuranyl group, a benzothienobenzothiophenyl group, a benzothienodibenzothienyl group, a benzothienobenzofuranyl group, a benzothienodibenzofuranyl group, a spiroacridinyl group linking the xanthene, a dihydroacridinyl group substituted with at least one C1 to C10 alkyl group, and an N-substituted spirofluorenyl group.

As an example, when R₁In the case of fused heteroaromatic radicals, e.g. unfused or fused carbazolyl, acridinyl, dihydroacridinyl, phenazinyl and phenazineWhen an oxazinyl group, the fused heteroaromatic group may be further substituted with 1 to 3 additional fused heteroaromatic groups. In this case, substitution to R₁Additional fused heteroaromatic groups of (a) may include, but are not limited to, carbazolyl, acridinyl, dihydroacridinyl, phenazinyl and/or phenoAn oxazine group.

By way of example, substitution to R may be made₁The aryl or heteroaryl group of (a) may have 1 to 3 aromatic or heteroaromatic rings. When may be substituted to R₁When the number of aromatic rings or heteroaromatic rings becomes large, the conjugated structure in the whole molecule is too long, and thus the organic compound may have an excessively reduced energy band gap. By way of example, substitution to R may be made₁The aryl and heteroaryl groups of (a) may include, but are not limited to, phenyl, biphenyl, naphthyl, anthracenyl, benzo-furyl, dibenzo-furyl, benzo-thienyl, dibenzo-thienyl, carbazolyl, acridinyl, phenazinyl, phenoxathiinAn oxazinyl group and/or a phenothiazinyl group.

In one exemplary aspect of the present invention,R₂to R₆C in each case₆-C₃₀The aromatic groups may independently comprise C₆-C₃₀Aryl radical, C₇-C₃₀Arylalkyl radical, C₆-C₃₀Aryloxy radical and C₆-C₃₀An arylamino group. R₂To R₆C in each case₃-C₃₀The heteroaromatic groups may independently comprise C₃-C₃₀Heteroaryl group, C₄-C₃₀Heteroarylalkyl radical, C₃-C₃₀Heteroaryloxy and C₃-C₃₀A heteroarylamino group. When R is₂To R₆C in each case₆-C₃₀Aromatic radicals or C₃-C₃₀When the heteroaromatic group is aryl or heteroaryl, R₂To R₆The aryl or heteroaryl group in (1) may be identical to, but not limited to, those described above which may be substituted for R₁Aryl or heteroaryl of (a).

In one exemplary aspect, R₄And R₅Each unsubstituted or substituted by C₁-C₁₀Alkyl, phenyl, and combinations thereof, or R₄And R₅Combine to form a fluorene ring. Further, Z may be S (sulfur).

As described above, the organic compound having the structure of chemical formula 1 includes a benzimidazole moiety having n-type characteristics and a condensed heteroaromatic moiety or a (hetero) aromatic amino group having p-type characteristics. The organic compound has high excited singlet state level and triplet state level, and has excellent thermal stability. When an organic compound is introduced into an emission layer such as an EML, holes and electrons may be injected into the EML in a balanced manner, and a recombination zone between the holes and the electrons may be uniformly disposed over the entire area of the EML, and thus, the OLED may maximize its light emission efficiency and light emission lifetime.

In addition, since the organic compound includes a condensed aromatic ring having a benzimidazole moiety, it has a wide energy bandgap between a HOMO (highest occupied molecular orbital) level and a LUMO (lowest unoccupied molecular orbital) level and high excited singlet level and triplet level, and thus it can be used as a host in EML. When an organic compound is used as a host in an EML, exciton energy of the host may be efficiently transferred to a dopant, and exciton quenching caused by interaction between singlet/triplet excitons of the host or the dopant and a peripheral hole (or electron) -polaron may be minimized. Accordingly, an OLED having excellent light emitting efficiency and improved color purity can be realized by introducing an organic compound into the light emitting layer.

In one exemplary aspect, the organic compound having the structure of chemical formula 1 may have, but is not limited to, an excited triplet level T1 equal to or greater than about 2.80eV or about 2.90 eV. Further, the organic compound may have, but is not limited to, a HOMO level of about-5.0 eV to about-6.3 eV, a LUMO level of about-0.5 eV to about-2.0 eV, and a bandgap between the HOMO and LUMO levels of about 3.0eV to about 4.7 eV. In addition, the organic compound having the structure of chemical formula 1 has excellent affinity for charges and a low HOMO level, and thus it may be applied to ETL, HBL, or N-type CGL disposed between light emitting parts.

In one exemplary aspect, in chemical formula 1, m is 1 and n is 0 (zero). Such an organic compound may include any one having the structure of the following chemical formula 2:

[ chemical formula 2]

In another exemplary aspect, in chemical formula 2, m is 0 (zero) and n is 1. Such an organic compound may include any one having the structure of the following chemical formula 3:

[ chemical formula 3]

[ organic light-emitting device and OLED ]

By applying the organic compound to the light emitting layer of the OLED, the OLED having a lower driving voltage, excellent light emitting efficiency, and improved light emitting lifetime can be realized. The OLED of the present disclosure may be applied to an organic light emitting device such as an organic light emitting display device or an organic light emitting lighting device. An organic light emitting display device including an OLED will be explained. Fig. 1 is a schematic cross-sectional view of an organic light emitting display device 100 according to an exemplary aspect of the present disclosure. All components of the organic light emitting display device according to all aspects of the present disclosure are operatively coupled and configured. As shown in fig. 1, the organic light emitting display device 100 includes a substrate 110, a thin film transistor Tr on the substrate 110, and an Organic Light Emitting Diode (OLED) D connected to the thin film transistor Tr.

The substrate 110 may include, but is not limited to, glass, thin flexible materials, and/or polymer plastics. For example, the flexible material may be selected from, but is not limited to, Polyimide (PI), Polyethersulfone (PES), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), Polycarbonate (PC), and combinations thereof. The substrate 110 on which the thin film transistor Tr and the OLED D are disposed forms an array substrate.

The buffer layer 122 may be disposed over the substrate 110, and the thin film transistor Tr is disposed over the buffer layer 122. The buffer layer 122 may be omitted.

The semiconductor layer 120 is disposed over the buffer layer 122. In one exemplary aspect, the semiconductor layer 120 may include, but is not limited to, an oxide semiconductor material. In this case, a light shielding pattern may be provided under the semiconductor layer 120, and the light shielding pattern may prevent light from being incident toward the semiconductor layer 120, thereby preventing the semiconductor layer 120 from being deteriorated by the light. Alternatively, the semiconductor layer 120 may include, but is not limited to, polysilicon. In this case, opposite edges of the semiconductor layer 120 may be doped with impurities.

A gate insulating layer 124 formed of an insulating material is disposed on the semiconductor layer 120. The gate insulating layer 124 may include, but is not limited to, an inorganic insulating material, such as silicon oxide (SiO)_x) Or silicon nitride (SiN)_x)。

A gate electrode 130 made of a conductive material such as metal is disposed over the gate insulating layer 124 to correspond to the center of the semiconductor layer 120. Although the gate insulating layer 124 is disposed over the entire region of the substrate 110 in fig. 1, the gate insulating layer 124 may be patterned the same as the gate electrode 130.

An interlayer insulating layer 132 formed of an insulating material is disposed on the gate electrode 130 and covers the entire surface of the substrate 110. The interlayer insulating layer 132 may include, but is not limited to, materials such as silicon oxide (SiO)_x) Or silicon nitride (SiN)_x) Or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating layer 132 has first and second semiconductor layer contact holes 134 and 136 exposing both sides of the semiconductor layer 120. The first and second semiconductor layer contact holes 134 and 136 are disposed on opposite sides of the gate electrode 130, spaced apart from the gate electrode 130. The first and second semiconductor layer contact holes 134 and 136 are formed in the gate insulating layer 124 in fig. 1. Alternatively, when the gate insulating layer 124 is patterned identically to the gate electrode 130, the first and second semiconductor layer contact holes 134 and 136 are formed only within the interlayer insulating layer 132.

A source electrode 144 and a drain electrode 146 formed of a conductive material such as metal are disposed on the interlayer insulating layer 132. The source and drain electrodes 144 and 146 are spaced apart from each other with respect to the gate electrode 130, and the source and drain electrodes 144 and 146 contact both sides of the semiconductor layer 120 through the first and second semiconductor layer contact holes 134 and 136, respectively.

The semiconductor layer 120, the gate electrode 130, the source electrode 144, and the drain electrode 146 constitute a thin film transistor Tr serving as a driving element. The thin film transistor Tr in fig. 1 has a coplanar structure in which the gate electrode 130, the source electrode 144, and the drain electrode 146 are disposed over the semiconductor layer 120. Alternatively, the thin film transistor Tr may have an inverted staggered structure in which a gate electrode is disposed below a semiconductor layer and source and drain electrodes are disposed above the semiconductor layer. In this case, the semiconductor layer may include amorphous silicon.

Gate and data lines crossing each other to define a pixel region, and a switching element connected to the gate and data lines may also be formed in the pixel region of fig. 1. The switching element is connected to a thin film transistor Tr as a driving element. Further, the power line is spaced in parallel with the gate line or the data line, and the thin film transistor Tr may further include a storage capacitor configured to constantly maintain the voltage of the gate electrode for one frame.

In addition, the organic light emitting display device 100 may include a color filter including a dye or a pigment for transmitting light of a specific wavelength emitted from the OLED D. For example, the color filter may transmit light of a specific wavelength such as red (R), green (G), blue (B), and/or white (W). Each of the color filters of red, green and blue may be formed in each pixel region, respectively. In this case, the organic light emitting display device 100 may implement full color through a color filter.

For example, when the organic light emitting display device 100 is a bottom emission type, the color filter may be disposed on the interlayer insulating layer 132 corresponding to the OLED D. Alternatively, when the organic light emitting display device 100 is a top emission type, the color filter may be disposed over the OLED D, i.e., over the second electrode 230.

A passivation layer 150 is disposed on the source and drain electrodes 144 and 146 over the entire substrate 110. The passivation layer 150 has a flat top surface and a drain contact hole 152, and the drain contact hole 152 exposes the drain electrode 146 of the thin film transistor Tr. Although the drain contact hole 152 is disposed on the second semiconductor layer contact hole 136, it may be spaced apart from the second semiconductor layer contact hole 136.

The OLED D includes a first electrode 210, and the first electrode 210 is disposed on the passivation layer 150 and connected to the drain electrode 146 of the thin film transistor Tr. The OLED D further includes a light emitting layer 220 and a second electrode 230, the light emitting layer 220 including at least one light emitting portion, each of the light emitting layer 220 and the second electrode 230 being sequentially disposed on the first electrode 210.

The first electrode 210 is disposed in each pixel region. The first electrode 210 may be an anode and include a conductive material having a relatively high work function value. For example, the first electrode 210 may include, but is not limited to, a transparent conductive material such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Tin Zinc Oxide (ITZO), tin oxide (SnO), zinc oxide (ZnO), Indium Cerium Oxide (ICO), aluminum-doped zinc oxide (AZO), and the like.

In one exemplary aspect, when the organic light emitting display device 100 is a bottom emission type, the first electrode 201 may have a single layer structure of a transparent conductive material. Alternatively, when the organic light emitting display device 100 is a top emission type, a reflective electrode or a reflective layer may be disposed under the first electrode 210. For example, the reflective electrode or layer may include, but is not limited to, silver (Ag) or aluminum-palladium-copper (APC) alloy. In the top emission type OLED D, the first electrode 210 may have a triple-layered structure of ITO/Ag/ITO or ITO/APC/ITO.

In addition, a bank layer 160 is disposed on the passivation layer 150 to cover an edge of the first electrode 210. The bank layer 160 exposes the center of the first electrode 210.

A light emitting layer 220 is disposed on the first electrode 210. In one exemplary aspect, the light emitting layer 220 may have a single-layer structure of a light Emitting Material Layer (EML). Alternatively, the light emitting layer 220 may have a multi-layer structure of a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an Electron Blocking Layer (EBL), an EML, a Hole Blocking Layer (HBL), an Electron Transport Layer (ETL), and/or an Electron Injection Layer (EIL) (see fig. 2,5, 7, and 9). In one aspect, the light emitting layer 220 may have a single light emitting portion. Alternatively, the light emitting layer 220 may have a plurality of light emitting portions to form a series structure.

The light emitting layer 220 includes any one of the structures having chemical formulas 1 to 3. As an example, the organic compound having the structure of chemical formulas 1 to 3 may be applied to a host in EML, or to ETL, HBL, and N-CGL.

The second electrode 230 is disposed over the substrate 110 over which the light emitting layer 220 is disposed. The second electrode 230 may be disposed over the entire display area and may include a conductive material having a relatively low work function value compared to the first electrode 210. The second electrode 230 may be a cathode. For example, the second electrode 230 may include, but is not limited to, aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), alloys thereof, or combinations thereof such as aluminum-magnesium alloy (Al-Mg). When the organic light emitting display device 100 is a top emission type, the second electrode 230 is thin, thereby having a light transmission (semi-transmission) characteristic.

In addition, an encapsulation film 170 may be disposed over the second electrode 230 to prevent external moisture from penetrating into the OLED D. The encapsulation film 170 may have, but is not limited to, a laminated structure of a first inorganic insulating film 172, an organic insulating film 174, and a second inorganic insulating film 176.

In addition, the organic light emitting display device 100 may have a polarizer to reduce external light reflection. For example, the polarizer may be a circular polarizer. When the organic light emitting display device 100 is a bottom emission type, the polarizer may be disposed under the substrate 100. Alternatively, when the organic light emitting display device 100 is a top emission type, the polarizer may be disposed over the encapsulation film 170. Further, the cover window may be attached to the encapsulation film 170 or the polarizer. In this case, the substrate 110 and the cover window may have a flexible characteristic, and thus the organic light emitting display device 100 may be a flexible display device.

As described above, the OLED D includes any one of the structures having chemical formulas 1 to 3 in the light emitting layer 220. The organic compound has excellent thermal stability and light emitting characteristics, and thus the OLED D may improve its light emitting efficiency, reduce its driving voltage and power consumption, and increase its light emitting life by applying the organic compound to the OLED D.

We will now describe the OLED in more detail. Fig. 2 is a schematic cross-sectional view illustrating an OLED according to one exemplary aspect of the present disclosure. As shown in fig. 2, the OLED D1 includes a first electrode 210 and a second electrode 230 facing each other, and a light emitting layer 220 having a single light emitting part disposed between the first electrode 210 and the second electrode 230. The organic light emitting display device 100 includes a red pixel region, a green pixel region, and a blue pixel region, and the OLED D1 may be disposed in any of the red, green, and blue pixel regions

In one exemplary aspect, the light emitting layer 220 includes an EML240 disposed between the first electrode 210 and the second electrode 230. In addition, the light emitting layer 220 may include at least one of an HTL 260 disposed between the first electrode 210 and the EML240, and an ETL 270 disposed between the second electrode 230 and the EML 240. In addition, the light emitting layer 220 may further include at least one of an HIL 250 disposed between the first electrode 210 and the HTL 260 and an EIL 280 disposed between the second electrode 230 and the ETL 270.

Alternatively, the light emitting layer 220 may further include a first exciton blocking layer (i.e., EBL 265) disposed between the HTL 260 and the EML240 and/or a second exciton blocking layer (i.e., HBL 275) disposed between the EML240 and the ETL 270.

The first electrode 210 may be an anode that provides holes into the EML 240. The first electrode 210 may include, but is not limited to, a conductive material having a relatively high work function value, such as a Transparent Conductive Oxide (TCO). In one exemplary aspect, the first electrode 210 may include, but is not limited to, ITO, IZO, ITZO, SnO, ZnO, ICO, AZO, and the like.

The second electrode 230 may be a cathode that provides electrons into the EML 240. The second electrode 230 may include, but is not limited to, a conductive material having a relatively low work function value, i.e., a highly reflective material, such as Al, Mg, Ca, Ag, alloys thereof, combinations thereof, and the like.

In this aspect, the EML240 may comprise a first compound (compound 1, host) and a second compound (compound 2) TD. For example, the first compound may be a (first) host and the second compound TD may be a dopant such as a fluorescent material, a phosphorescent material, and a delayed fluorescent material. Hereinafter, the EML240 in which the second compound is a delayed fluorescent material will be explained. As an example, an organic compound having the structure of chemical formulas 1 to 3 may be used as a host. For example, the EML240 may emit red (R), green (G), or blue (B) light.

The HIL 250 is disposed between the first electrode 210 and the HTL 260, and improves the interface characteristics between the inorganic first electrode 210 and the organic HTL 260. In one exemplary aspect, HIL 250 can include, but is not limited to, 4 ', 4 ″ -tris (3-methylphenylamino) triphenylamine (MTDATA), 4', 4 ″ -tris (N, N-diphenyl-amino) triphenylamine (NATA), 4 ', 4 ″ -tris (N- (naphthalen-1-yl) -N-phenyl-amino) triphenylamine (1T-NATA), 4', 4 ″ -tris (N- (naphthalen-2-yl) -N-phenyl-amino) triphenylamine (2T-NATA), copper phthalocyanine (CuPc), tris (4-carbazol-9-yl-phenyl) amine (TCTA), N '-diphenyl-N, N' -bis (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine (NPB; NPD), 1,4,5,8,9, 11-hexaazatriphenylene hexacarbonitrile (bipyrazine [2,3-f:2 '3' -H ] quinoxaline-2, 3,6,7,10, 11-hexacarbonitrile; HAT-CN), 1,3, 5-tris [4- (diphenylamino) phenyl ] benzene (TDAPB), poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) and/or N- (biphenyl-4-yl) -9, 9-dimethyl-N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluoren-2-amine. The HIL 250 may be omitted according to the structure of the OLED D1.

The HTL 260 is disposed adjacent to the EML240 between the first electrode 210 and the EML 240. In one exemplary aspect, HTL 260 may include, but is not limited to, N ' -diphenyl-N, N ' -bis (3-methylphenyl) -1,1 ' -biphenyl-4, 4 ' -diamine (TPD), NPB, 4 ' -bis (N-carbazolyl) -1,1 ' -biphenyl (CBP), poly [ N, N ' -bis (4-butylphenyl) -N, N ' -bis (phenyl) -benzidine ] (poly-TPD), poly [ (9, 9-dioctylfluorenyl-2, 7-diyl) -co- (4,4 ' - (N- (4-sec-butylphenyl) diphenylamine)) ] (TFB), bis- [4- (N, N-di-p-tolyl-amino) -phenyl ] cyclohexane (TAPC), 3, 5-bis (9H-carbazol-9-yl) -N, N-diphenylamine (DCDPA), N- (biphenyl-4-yl) -9, 9-dimethyl-N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluoren-2-amine and/or N- (biphenyl-4-yl) -N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) biphenyl-4-amine.

The ETL 270 and the EIL 280 may be sequentially laminated between the EML240 and the second electrode 230. The ETL 270 includes a material having high electron mobility so as to stably supply electrons to the EML240 through rapid electron transport.

In one exemplary aspect, the ETL 270 may include, but is not limited to, oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, triazine-based compounds, and the like.

As an example, ETL 270 may include, but is not limited to, aluminum tris- (8-hydroxyquinoline (Alq)₃) 2-biphenyl-4-yl-5- (4-tert-butylphenyl) -1,3, 4-diazole (PBD), spiro-PBD, lithium quinolinate (Liq), 1,3, 5-tris (N-phenylbenzimidazol-2-yl) benzene (TPBi), bis (2-methyl-8-hydroxyquinoline-N1, O8) - (1, 1' -biphenyl-4-ol) aluminum (BALq), 4, 7-diphenyl-1, 10-phenanthroline (Bphen), 2, 9-bis (naphthalen-2-yl) 4, 7-diphenyl-1, 10-phenanthroline (NBphen), 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), 3- (4-biphenylyl) -4-phenyl-5-tert-butylphenyl-1, 2, 4-Triazole (TAZ), 4- (naphthalen-1-yl) -3, 5-diphenyl-4H-1, 2, 4-triazole (NTAZ), 1,3, 5-tris (p-pyridin-3-yl-phenyl) benzene (TpPyPB), 2,4, 6-tris (3 '- (pyridin-3-yl) biphenyl-3-yl) 1,3, 5-triazine (TmPPPyTz), poly [9, 9-bis (3' - (N, N-dimethyl) -N-ethylammonium) -propyl) -2, 7-fluorene]-alt-2, 7- (9, 9-dioctylfluorene)](PFNBr), tris (phenylquinoxaline) (TPQ) and/or diphenyl-4-triphenylsilyl-phenylphosphine oxide (TSPO 1).

In another exemplary aspect, the ETL 270 may include any one of the structures having chemical formulas 1 to 3. The organic compound has excellent electron affinity. In this case, the ETL 270 may contain only the organic compounds having the structures of chemical formulas 1 to 3, or the above-described electron transport materials mixed with or doped with the organic compounds.

The EIL 280 is disposed between the second electrode 230 and the ETL 270, and may improve physical characteristics of the second electrode 230, and thus may improve the OLED D1And (4) service life. In an exemplary aspect, EIL 280 can include, but is not limited to, an alkali metal halide or an alkaline earth metal halide such as LiF, CsF, NaF, BaF₂Etc., and/or organometallic compounds such as lithium quinolinate, lithium benzoate, sodium stearate, etc.

The OLED D1 may have a short lifetime and reduced light emitting efficiency when holes are transported to the second electrode 230 via the EML240 and/or electrons are transported to the first electrode 210 via the EML 240. To prevent these phenomena, the OLED D1 according to this aspect of the present disclosure may have at least one exciton blocking layer adjacent to the EML 240.

For example, OLED D1 of the exemplary aspect includes EBL 265 between HTL 260 and EML240 to control and prevent electron transport. In an exemplary embodiment, EBL 265 may include, but is not limited to: TCTA, tris [4- (diethylamino) phenyl ] amine, N- (biphenyl-4-yl) -9, 9-dimethyl-N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluoren-2-amine, TAPC, MTDATA, 1, 3-bis (carbazol-9-yl) benzene (mCP), 3 '-bis (N-carbazolyl) -1, 1' -biphenyl (mCBP), CuPc, N '-bis [4- (bis (3-methylphenyl) amino) phenyl ] -N, N' -diphenyl- [1,1 '-biphenyl ] -4, 4' -diamine (DNTPD), TDAPB, DCDPA and/or 2, 8-bis (9-phenyl-9H-carbazol-3-yl) dibenzo [ B ], (N, N '-biphenyl-4, 4' -diamine (DNTPD) b, d ] thiophene.

In addition, OLED D1 may also include HBL 275 as a second exciton blocking layer between EML240 and ETL 270, such that holes cannot be transported from EML240 to ETL 270. In one exemplary aspect, HBL 275 can comprise, but is not limited to, oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, benzoxazole-based compounds, benzothiazole-based compounds, benzimidazole-based compounds, triazine-based compounds, and the like, each of which can be used in ETL 270.

For example, HBL 275 may comprise a compound having a relatively low HOMO level compared to the light emitting material in EML 240. HBL 275 may include, but is not limited to, mCBP, BCP, BALq, Alq₃PBD, spiro-PBD, Liq, bis-4, 5- (3, 5-di-3-pyridylphenyl) -2-methylpyrimidine (B3PYMPM), DPEPO, 9- (6- (9H-carbazol-9-yl) pyridin-3-yl) -9H-3, 9' -bicarbazole, TSPO1, and combinations thereof.

In another exemplary aspect, HBL 275 may comprise any one of the structures of formulas 1 to 3. The organic compound has a deep HOMO level for blocking holes. In this case, the HBL 275 may contain only the organic compound having the structure of chemical formulas 1 to 3, or the above-described hole blocking material mixed with or doped with the organic compound.

As described above, the EML240 in the first aspect includes the first compound that is any one of the structures having chemical formulas 1 to 3, and the second compound that may have delayed fluorescence characteristics.

In the prior art, EML240 uses a p-type host with excellent hole affinity. When a p-type host is applied in EML240, a recombination region between holes and electrons is formed at the interface between EML240 and HBL 275, because the p-type host prefers holes instead of electrons. In this case, some charges injected into the EML240 cannot be recombined with opposite charges to be quenched without participating in the light emitting process, and thus, the light emitting efficiency is deteriorated.

In contrast, the organic compounds having the structures of chemical formulas 1 to 3 are bipolar compounds. When an organic compound is applied to the bulk in the EML240, the recombination zone between holes and electrons is uniformly distributed in the entire region of the EML240 including the interface between the EML240 and the EBL 265. In other words, when an organic compound is applied to the EML240, most holes and electrons injected into the EML240 recombine without quenching, and the OLED D1 may maximize its light emitting efficiency.

External quantum efficiency (EQE, η) of luminescent materials applied in EML_{Exterior part}) Is determined by four factors, such as the singlet/triplet ratio, the charge balance factor, the radiation efficiency and the outcoupling efficiency. Since the fluorescent material uses only singlet excitons in the course of light emission, the maximum light emission efficiency of the OLED using the conventional fluorescent material is only about 5%.

On the other hand, phosphorescent materials have a light emitting mechanism that converts both singlet excitons and triplet excitons into light. Phosphorescent materials convert singlet excitons into triplet excitons through intersystem crossing (ISC). Therefore, when a phosphorescent material using both singlet excitons and triplet excitons is used, the low light emission efficiency of the fluorescent material can be improved. However, the blue phosphorescent material has too low color purity and too short life to be applied to commercial display devices. Therefore, there is a need to improve the disadvantages of phosphorescent materials and the low luminous efficiency of blue light emitting materials.

Delayed fluorescence materials have been developed that can solve the problems associated with conventional art fluorescent and/or phosphorescent materials. Representative delayed fluorescence materials are thermally-activated delayed fluorescence (TADF) materials. Fig. 3 is a schematic diagram showing a light emitting mechanism of a delayed fluorescent material in EML.

As shown in FIG. 3, the singlet energy level S in the delayed fluorescent material TD₁ ^TDExciton and triplet level T₁ ^TDMay be transferred to an intermediate energy level state, i.e., ICT state, and then the excitons in the intermediate state may be transferred to a ground state (S)₀ ^TD；S₁ ^TD→ICT←T₁ ^TD). Since compounds with ICT states have little orbital overlap between HOMO and LUMO, there is little interaction between the HOMO and LUMO states. Therefore, the change in the spin state of the electron has no influence on other electrons, and a new charge transfer band (CT band) that does not follow the selection rule is formed within the delayed fluorescent material. When an OLED including the delayed fluorescent material TD is driven, 25% of both singlet excitons and 75% of triplet excitons are converted into an ICT state by heating, and then the converted excitons are transferred to a ground state S₀It emits light. Therefore, the delayed fluorescent material TD may theoretically have an internal quantum efficiency of 100%.

The delayed fluorescent material TD must have an excited singlet energy level S₁ ^TDAnd excited triplet state energy level T₁ ^TDAn energy band gap Δ E of equal to or less than about 0.3eV, such as from about 0.05eV to about 0.3eV_ST ^TDSo as to excite singlet state energy level S₁ ^TDAnd excited triplet state energy level T₁ ^TDThe exciton energy in both can be transferred to ICT state. At the singlet energy level S₁ ^TDAnd triplet state energy level T₁ ^TDMaterials having a small energy band gap therebetween can exhibit a singlet state energy level S therein₁ ^TDCan be directly transferred to the ground state S₀ ^TDGeneral fluorescence of (2); and exhibits delayed fluorescence by means of intersystem crossing (RISC), wherein the triplet level T₁ ^TDThe exciton can be transferred to the singlet energy level S₁ ^TDThen from the triplet level T₁ ^TDTransferred singlet energy level S₁ ^TDCan be transferred to the ground state S₀ ^TD。

Since the delayed fluorescent material TD theoretically obtains a luminous efficiency of 100%, it can realize an excellent internal quantum efficiency as the conventional phosphorescent material. In this case, the host may induce triplet excitons at the delayed fluorescent material to participate in the luminescence process without quenching or non-radiative recombination. For this purpose, the energy level between the host and the delayed fluorescent material should be adjusted.

Fig. 4 is a schematic diagram illustrating a light emitting mechanism by an energy level band gap between light emitting materials according to an exemplary aspect of the present disclosure. As shown in FIG. 4, the excited singlet level S of the first compound H, which can be the host in EML240₁ ^HAnd excited triplet state energy level T₁ ^HIs higher than an excited singlet level S of a second compound TD having a delayed fluorescence characteristic₁ ^TDAnd excited triplet state energy level T₁ ^TDEach of the above. As an example, the excited triplet level T of the first compound H₁ ^HExcited triplet level T which can be compared with that of the second compound TD₁ ^TDAt least about 0.2eV, at least about 0.3eV, or at least about 0.5 eV.

When excited triplet level T of first compound H₁ ^HAnd excited singlet energy level S₁ ^HIs no more than the excited triplet level T of the second compound TD₁ ^TDAnd excited singlet energy level S₁ ^TDOf the second compound TD is highThe triplet exciton energy can be transferred back to the excited triplet level T of the first compound H₁ ^H. In this case, the triplet excitons transferred back to the first compound H incapable of emitting triplet excitons as non-luminescence quenching make the triplet exciton energy of the second compound TD having delayed fluorescence characteristics unable to contribute to luminescence. Excited singlet state level S of second compound TD with delayed fluorescence characteristic₁ ^TDAnd excited triplet state energy level T₁ ^TDEnergy band gap Δ E between_ST ^TDMay be equal to or less than about 0.3eV, for example from about 0.05eV to about 0.3eV (see fig. 3).

Further, the HOMO level and the LUMO level of the first compound H and the second compound TD need to be appropriately adjusted. For example, the HOMO energy level (HOMO) of the first compound H^H) HOMO energy level (HOMO) with second compound TD^TD) Energy level band gap (| HOMO)^H-HOMO^TDI), or the LUMO energy Level (LUMO) of the first compound H^H) With the LUMO energy Level (LUMO) of the second compound TD^TD) Bandgap of energy level (| LUMO)^H-LUMO^TDI) may be equal to or less than about 0.5eV, for example, from about 0.1eV to about 0.5 eV.

When the EML240 includes the first compound H (any organic compound having the structure of chemical formulas 1 to 3) and the second compound TD having the delayed fluorescence characteristic, exciton energy may be transferred to the second compound TD without losing energy during light emission. In this case, it is possible to minimize exciton quenching caused by interaction between the host exciton and the adjacent polaron and to prevent a reduction in emission lifetime due to electrooxidation and photooxidation.

The second compound may be a delayed fluorescent material that emits blue light, green light, or red light. In one exemplary aspect, the second compound as the blue luminescence delayed fluorescence material in EML240 may include, but is not limited to, 10- (4- (diphenylphosphoryl) phenyl) -10H-phenazine (SPXZPO), 10 ' - (4,4 ' - (phenylphosphoryl) bis (4, 1-phenylene)) bis (10H-phenazine) (DPXZPO), 10 ', 10 ″ - (4,4 ', 4 ″ -phosphoryltris (benzene-4, 1-diyl)) tris (10H-phenazine (TPXZPO), 9 ' - (5- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -1, 3-phenylene) bis (9H-carbazole) (DcZTrz), 9 ', 9 ", 9" ' - ((6-phenyl-1, 3, 5-triazine-2, 4-diyl) bis (benzene-5, 3, 1-triyl)) tetrakis (9H-carbazole (DDczTrz), 2, 7-bis (9, 9-dimethylacridin-10 (9H) -yl) -9, 9-dimethyl-9H-thioxanthene-10, 10-dioxide (DMTDAc), 9 '- (4, 4' -sulfonylbis (4, 1-phenylene)) bis (3, 6-dimethoxy-9H-carbazole) (DMOC-DPS), 10 '- (4, 4' -sulfonylbis (4, 1-phenylene)) bis (9, 9-dimethyl-9, 10-dihydroacridine (DMAC-DPS), 10- (4- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl) -9, 9-dimethyl-9, 10-dihydroacridine (DMAC-TRZ), 10-phenyl-10H, 10 'H-spiro [ acridine-9, 9' -anthracene ] -10 '-one (ACRSA), 3, 6-dibenzoyl-4, 5-bis (1-methyl-9-phenyl-9H-carbazolyl) -2-ethynylbenzonitrile (Cz-VPN), 9', 9 "- (5- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) benzene-1, 2, 3-triyl) tris (9H-carbazole) (TcZTrz), 2 ' - (10H-phenazin-10-yl) - [1,1 ': 3 ', 1 "-terphenyl ] -5 ' -carbonitrile (mPTC), bis (4- (9H-3,9 ' -bicarbazol-9-yl) phenyl) methanone (CC2BP), 9 ' - [4- (4, 6-diphenyl-1, 3, 5-triazine-2-yl) phenyl ] -3, 3", 6,6 "-tetraphenyl-9, 3 ': 6 ', 9" -ter-9H-carbazole (BDPCC-TPTA), 9 ' - [4- (4, 6-diphenyl-1, 3, 5-triazine-2-yl) phenyl ] -9,3 ': 6 ', 9 "-ter-9H-carbazole (BCC-TPTA), 9- (4- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl) -3 ', 6 ' -diphenyl-9H-3, 9 ' -bicarbazole (DPCC-TPTA), 10- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -10H-phenazine (Phen-TRZ), 9- (4- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl) -9H-carbazole (Cab-Ph-TRZ), 10- (4- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl) -10H-spiro [ acridine-9 ], 9' -fluorene ] (spiro AC-TRZ), 4, 6-bis (9H-carbazol-9-yl) isophthalonitrile (DczIPN), 3CzFCN and 2,3,4, 6-tetrakis (9H-carbazol-9-yl) -5-fluorobenzonitrile (4 CzFCN).

In another aspect, the second compound as the green emission-delayed fluorescent material in EML240 may include, but is not limited to, 5 ' - (phenazin-10-yl) - [1,1 ': 3 ', 1 "-terphenyl ] -2 ' -carbonitrile (otcp), 2-biphenyl-4, 6-bis (12-phenylindole [2,3-a ] carbazol-11-yl) -1,3, 5-triazine (PIC-TRZ), 9 ', 9" - (5- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) benzene-1, 2, 3-triyl) tris (3, 6-dimercapto-9H-carbazole (tmztrz), 2, 5-bis (4- (10H-phenazin-10-yl) phenyl) -1,3, 4-oxadiazole (2PXZ-OXD), bis (4- (9, 9-dimethylacridin-10 (9H) -yl) phenyl) methanone (DMAC-BP), 2- (9-phenyl-9H-carbazol-3-yl) -10, 10-dioxide-9H-thioxanthen-9-one (TXO-PhCz), 2,4,5, 6-tetrakis (9H-carbazol-9-yl) isophthalonitrile (4CzIPN), 3,4,5, 6-tetrakis (9H-carbazol-9-yl) isophthalonitrile (4CzPN), 2,3,4, 6-tetrakis (9H-carbazol-9-yl) -5-fluorobenzonitrile (4CzFCN), 6- (9H,9 'H- [3, 3' -biscarbazole ] -9,9 '-diyl) bis (4- (9H-carbazol-9-yl) isophthalonitrile (33TczPN), 4, 5-bis (5H-benzofuran [3,2-c ] carbazol-5-yl) phthalonitrile (BFCz-2CN), 4, 5-bis (5H-benzo [4,5] thieno [3,2-c ] carbazol-5-yl) phthalonitrile (BTCz-2CN), 4' -bis (9, 9-dimethylacridin-10 (9H) -yl) - [1,1 ': 2', 1 '-terphenyl ] -4', 5 '-dicarbonitrile (Ac-VPN), 4' -bis (10H-phenazin-10-yl) - [1,1 ': 2 ', 1 "-terphenyl ] -4 ', 5 ' -dicarbonitrile (Px-VPN), 5 ' - (9H,9 ' H- [3,3 ' -bicarbazole ] -9,9 ' -diyl) bis-isophthalonitrile (35IPNDcz), 2,5 ' - (9H,9 ' H- [3,3 ' -bicarbazole ] -9,9 ' -diyl) bis-isophthalonitrile (26IPNDcz), 9 ', 9" - (5- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) benzene-1, 2, 3-triyl) tris (9H-carbazole) (TcZTrz) and 32 alCTRZ.

In yet another exemplary aspect, the second compound as the red light emitting delayed fluorescence material in EML240 may include, but is not limited to, 1, 3-bis [4- (10H-phenazine-10-yl) benzoyl ] benzene (mPx2BBP), 2,3,5, 6-tetrakis (3, 6-diphenylcarbazol-9-yl) -1, 4-dicyanobenzene (4CzTPN-Ph), 10' - (sulfonylbis (4, 1-phenylene)) bis (5-phenyl-5, 10-dihydrophenazine) (PPZ-DPS), 5, 10-bis (4- (benzo [ d ] thiazol-2-yl) phenyl) -5, 10-dihydrophenazine (DHPZ-2BTZ), 5, 10-bis (4- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl) -5, 10-dihydrophenazine (DHPZ-2TRZ) and 7, 10-bis (4- (diphenylamino) phenyl) -2, 3-dicyanopyrazinophenanthrene (TPA-DCPP).

When the EML240 includes the first compound H as a host and the second compound TD as a delayed fluorescent material, the content of the second compound TD in the EML240 may be, but is not limited to, about 1 wt% to about 70 wt%, about 10 wt% to about 50 wt%, or about 20 wt% to about 50 wt%.

The EML may contain multiple dopants with different light emitting characteristics. Fig. 5 is a schematic cross-sectional view illustrating an OLED according to another exemplary aspect of the present disclosure. As shown in fig. 5, the OLED D2 includes a first electrode 210, a second electrode 230 facing the first electrode 210, and a light emitting layer 220A disposed between the first electrode 210 and the second electrode 230. The light emitting layer 220A having a single light emitting part includes an EML 240A. The organic light emitting display device 100 (fig. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the OLED D2 may be disposed in any of the red, green, and blue pixel regions.

The light emitting layer 220A may include at least one of an HTL 260 disposed between the first electrode 210 and the EML240 and an ETL 270 disposed between the second electrode 230 and the EML 240. In addition, the light emitting layer 220A may further include at least one of an HIL 250 disposed between the first electrode 210 and the HTL 260 and an EIL 280 disposed between the second electrode 230 and the ETL 270. Alternatively, the light emitting layer 220A may further include an EBL 265 disposed between the HTL 260 and the EML 240A and/or an HBL 275 disposed between the EML 240A and the ETL 270. The first and second electrodes 210 and 230 and the other layers in the light emitting layer 220A except the EML 240A are substantially the same in construction as the corresponding electrodes and layers in the OLED D1.

In a second aspect, EML 240A comprises a first compound (compound 1, host) H, a second compound (compound 2, first dopant) TD, and a third compound (compound 3, second dopant) FD. The first compound H may be a host, the second compound TD may be a delayed fluorescent material, and the third compound FD may be a fluorescent material. The first compound H may include any organic compound having the structure of chemical formulas 1 to 3. When the EML 240A further includes a fluorescent material and a delayed fluorescent material as a dopant, the OLED D2 may further improve its luminous efficiency and color purity by adjusting the energy level between these light emitting materials.

When the EML contains only the second compound having a delayed fluorescence characteristic as a dopant, the EML can achieve high internal quantum efficiency as the prior art phosphorescent material containing a heavy metal since the dopant can theoretically exhibit 100% internal quantum efficiency.

However, due to bond formation and conformational distortion between the electron acceptor and the electron donor within the delayed fluorescent material, additional charge transfer transitions (CT transitions) within the delayed fluorescent material are caused thereby, and the delayed fluorescent material has various geometries. Therefore, the delayed fluorescent material shows a light emission spectrum having a very wide FWHM (full width at half maximum) during light emission, which results in poor color purity. In addition, the delayed fluorescent material utilizes triplet exciton energy as well as singlet exciton energy during light emission while rotating every part within its molecular structure, which results in Twisted Internal Charge Transfer (TICT). Therefore, the emission lifetime of the OLED including only the delayed fluorescent material may be reduced due to the decrease of molecular bonding force between the delayed fluorescent materials.

In the second aspect, in the case of using only a delayed fluorescence material as a dopant, in order to prevent color purity and emission lifetime from being reduced, the EML 240A further contains a third compound which may be a fluorescent or phosphorescent material. As shown in fig. 6, the triplet exciton Energy of the second compound TD having the delayed fluorescence characteristic is up-converted into its own singlet exciton Energy by the RISC mechanism, and then the converted singlet exciton Energy of the second compound TD may be transferred to the third compound FD (which may be a fluorescent or phosphorescent material) in the same EML 240A by the Forster Resonance Energy Transfer (FRET) mechanism to achieve super fluorescence.

When the EML 240A includes the first compound H, which may be any organic compound having a structure of chemical formulas 1 to 3, the second compound TD having delayed fluorescence characteristics, and the third compound FD, which is a fluorescent or phosphorescent material, it is necessary to appropriately adjust the energy level between these light emitting materials. Fig. 6 is a schematic diagram illustrating a light emitting mechanism by an energy level band gap between light emitting materials according to another exemplary aspect of the present disclosure.

Excited singlet level S of second compound TD as delayed fluorescent material₁ ^TDAnd excited triplet state energy level T₁ ^TDEnergy band gap Δ E between_ST ^TDMay be equal to or less than about 0.3eV to achieve delayed fluorescence (see fig. 3). Further, an excitation single line of the first compound H as a main bodyState energy level S₁ ^HAnd excited triplet state energy level T₁ ^HEach of which is respectively higher than an excited singlet level S of a second compound TD as a delayed fluorescent material₁ ^TDAnd excited triplet state energy level T₁ ^TDEach of the above. As an example, the excited triplet level T of the first compound H₁ ^HExcited triplet level T which can be compared with that of the second compound TD₁ ^TDAt least about 0.2eV higher.

In addition, excited triplet level T of second compound TD₁ ^TDExcited triplet level T higher than third compound FD as fluorescent or phosphorescent material₁ ^FD. In one exemplary aspect, the excited singlet level S of the second compound TD₁ ^TDExcited singlet level S that may be higher than third compound FD₁ ^FD。

Further, the HOMO level (HOMO) of the first compound H as a host^H) HOMO energy level (HOMO) with a second compound TD as a delayed fluorescent material^TD) Energy level band gap (| HOMO)^H-HOMO^TDI), or the LUMO energy Level (LUMO) of the first compound H^H) With the LUMO energy Level (LUMO) of the second compound TD^TD) Bandgap of energy level (| LUMO)^H-LUMO^TD|) may be equal to or less than about 0.5 eV.

For example, the first compound H, which may be a host, may include any organic compound having the structure of chemical formulas 1 to 3. The second compound may comprise an organic compound as described in the first aspect.

The exciton energy should be efficiently transferred from the second compound TD, which is a delayed fluorescent material, to the third compound FD, which is a fluorescent or phosphorescent material, to achieve super fluorescence. As an example, a fluorescent or phosphorescent material having an absorption spectrum with a large overlap region with the emission spectrum of the second compound TD having a delayed fluorescence characteristic may be used as the third compound FD to efficiently transfer exciton energy from the second compound to the third compound.

The third compound FD may emit blue (B), green (G), or red (R) light. In one exemplary aspect, the third compound FD as a fluorescent material may emit blue (B) light. For example, the third compound may include, but is not limited to, pyrene-based compounds, anthracene-based compounds, fluoranthene-based compounds, and boron-based compounds. For example, the third compound FD, which is a fluorescent material emitting blue light, may include any one of the structures having the following chemical formula 4:

[ chemical formula 4]

In another exemplary aspect, the third compound FD as a green light-emitting fluorescent material may include, but is not limited to, a boron-dipyrromethene (4, 4-difluoro-4-boron-3 a,4 a-diaza-s-indacene, BODIPY) nucleus. Alternatively, a metal complex which is a phosphorescent material emitting blue, green, or red may be used as the third compound FD.

In one exemplary aspect, the content of the first compound H may be greater than the content of the second compound TD, and the content of the second compound TD is greater than the content of the third compound FD. In this case, the exciton energy may be efficiently transferred from the second compound TD to the third compound FD via a FRET mechanism. As an example, the contents of the first to third compounds H, TD and FD in the EML 240A may each be, but are not limited to, about 60 wt% to about 75 wt%, about 20 wt% to about 40 wt%, and about 0.1 wt% to about 5 wt%, respectively.

Alternatively, an OLED according to the present disclosure may include multiple layers of EMLs. Fig. 7 is a schematic cross-sectional view illustrating an OLED having a dual-layer EML according to another exemplary aspect of the present disclosure. Fig. 8 is a schematic diagram illustrating a light emitting mechanism by an energy level band gap between light emitting materials according to another exemplary aspect of the present disclosure.

As shown in fig. 7, the OLED D3 includes a first electrode 310 and a second electrode 330 facing each other, and a light emitting layer 320 having a single light emitting unit disposed between the first electrode 310 and the second electrode 330.

In one exemplary aspect, the light emitting layer 320 includes an EML 340. The organic light emitting display device 100 (fig. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the OLED D3 may be disposed in any of the red, green, and blue pixel regions. The light emitting layer 320 may include at least one of an HTL 360 disposed between the first electrode 310 and the EML340 and an ETL 370 disposed between the second electrode 230 and the EML 340. In addition, the light emitting layer 320 may further include at least one of an HIL 350 disposed between the first electrode 310 and the HTL 360 and an EIL380 disposed between the second electrode 330 and the ETL 370. Alternatively, the light emitting layer 320 may further include an EBL 365 disposed between the HTL 360 and the EML340 and/or an HBL 375 disposed between the EML340 and the ETL 370. The configurations of the first and second electrodes 310 and 330 and the other layers in the light emitting layer 320 except the EML340 are substantially the same as the corresponding electrodes and layers in the OLED D1 or the OLED D2.

The EML340 includes a first EML (EML1, lower EML, first layer) 342 and a second EML (EML2, upper EML, second layer) 344. EML 1342 is disposed between EBL 365 and HBL 375 and EML2344 is disposed between EML 1342 and HBL 375. One of EML 1342 and EML2344 contains a second compound (compound 2, first dopant) TD as a delayed fluorescent material, and the other of EML 1342 and EML2344 contains a fifth compound (compound 5, second dopant) FD as a fluorescent or phosphorescent material. In addition, EML 1342 and EML2344 each contained a first compound (compound 1, first host (host 1)) H1 and a fourth compound (compound 4, second host (host 2)) H2, respectively. In an exemplary third aspect, EML 1342 comprises a first compound H1, which may be a first host, and a second compound TD, which may be a delayed fluorescence material. EML2344 comprises a fourth compound H2, which may be a second host, and a fifth compound FD, which may be a fluorescent or phosphorescent material.

More specifically, EML 1342 includes a first compound H1 as any organic compound having a structure of chemical formulas 1 to 3 and a second compound TD as a delayed fluorescence material. The triplet exciton energy of the second compound TD may be converted to its own singlet exciton energy via a RISC mechanism. Although the second compound has high internal quantum efficiency, it has poor color purity due to its broad FWHM (full width at half maximum).

In contrast, EML2344 may contain a fourth compound H2, which may be a second host, and a fifth compound FD, which is a fluorescent or phosphorescent material. Although the fifth compound FD, which is a fluorescent material, has an advantage in color purity due to its narrow FWHM, its internal quantum efficiency is low because its triplet excitons may not participate in the light emitting process.

However, in this exemplary aspect, the singlet exciton energy and triplet exciton energy of the second compound having delayed fluorescence properties in EML 1342 may be transferred to the fifth compound, which may be a fluorescent or phosphorescent material, in EML2344 disposed adjacent to EML 1342 through a FRET mechanism (which non-radiatively transfers energy through an electric field generated by dipole-dipole interaction). Thus, the final luminescence occurs in the fifth compound within EML 2344.

In other words, the triplet exciton energy of the second compound TD in EML 1342 is up-converted to its own singlet exciton energy by the RISC mechanism. Then, the converted singlet exciton energy of the second compound TD is transferred to the singlet exciton energy of the fifth compound FD in EML 2344. The fifth compound FD in EML2344 can emit light using triplet exciton energy as well as singlet exciton energy. Since exciton energy generated at the second compound TD having delayed fluorescence characteristics in the EML 1342 is efficiently transferred from the second compound TD to the fifth compound FD as a fluorescent or phosphorescent material in the EML2344, super fluorescence may be achieved. In this case, substantial light emission occurs in EML2344 containing the fifth compound FD, which is a fluorescent or phosphorescent material and has a narrow FWHM. Thus, the OLED D3 can improve its quantum efficiency and improve its color purity due to the narrow FWHM.

EML 1342 and EML2344 each comprise a first compound H1 as a first host and a fourth compound H2 as a second host, respectively. The exciton energy generated at the first compound H1 and the fourth compound H2 should be transferred to the second compound TD as a delayed fluorescent material to emit light. As shown in figure 8 of the drawings,excited singlet level S of first compound H1 and fourth compound H2₁ ^H1And S₁ ^H2And excited triplet state energy level T₁ ^H1And T₁ ^H2Should be respectively higher than the excited singlet level S of the second compound TD as delayed fluorescent material₁ ^TDAnd excited triplet state energy level T₁ ^TDEach of the above. As an example, the excited triplet level T of the first compound H1 and the fourth compound H2₁ ^H1And T₁ ^H2May be lower than the excited triplet level T of the second compound TD₁ ^TDAt least about 0.2eV, such as at least about 0.3eV, or at least about 0.5 eV.

Excited singlet level S of fourth compound H2₁ ^H2Excited singlet level S higher than FD of fifth Compound₁ ^FD. In this case, singlet exciton energy generated at the fourth compound H2 may be transferred to excited singlet energy level S of the fifth compound FD₁ ^FD. Optionally, excited triplet level T of fourth compound H2₁ ^H2Excited triplet level T which may be higher than the fifth compound FD₁ ^FD。

In addition, the EML340 must achieve high luminous efficiency and color purity, and efficiently transfer exciton energy from the second compound TD in the EML 1342 (which is converted into the ICT complex state by the RISC mechanism) to the fifth compound FD as a fluorescent or phosphorescent material in the EML 2344. To realize such an OLED D3, the excited triplet level T of the second compound TD₁ ^TDExcited triplet level T higher than FD of fifth Compound₁ ^FD. Optionally, excited singlet level S of second compound TD₁ ^TDExcited singlet level S which may be higher than FD of the fifth compound₁ ^FD。

In addition, the HOMO level (HOMO) of the first compound H1 and/or the fourth compound H2^H) HOMO energy level (HOMO) with second compound TD^TD) Energy level band gap (| HOMO)^H-HOMO^TD|), or the first compound H1 and/orLUMO energy Level (LUMO) of fourth compound H2^H) With the LUMO energy Level (LUMO) of the second compound TD^TD) Bandgap of energy level (| LUMO)^H-LUMO^TD|) may be equal to or less than about 0.5 eV. When the light emitting material does not satisfy the required energy levels as described above, exciton energy is quenched at the second compound TD and the fifth compound FD, or exciton energy is not efficiently transferred from the first compound H1 and the fourth compound H2 to the second compound TD and the fifth compound FD, so that the OLED D3 may have a reduced quantum efficiency.

The first compound H1 and the fourth compound H2 may be the same as or different from each other. For example, each of the first compound H1 and the fourth compound H2 may independently include any organic compound having a structure of chemical formulas 1 to 3. The second compound TD may be the same as described above.

The fifth compound FD may have a narrow FWHM and have an absorption spectrum having a large overlapping region with the emission spectrum of the second compound TD. The fifth compound FD may be a fluorescent or phosphorescent material emitting blue, green or red light. For example, the fifth compound FD may be a fluorescent or phosphorescent material emitting blue, green, or red light as described above.

In an exemplary embodiment, the contents of the first compound H1 and the fourth compound H2 in the EML 1342 and the EML2344 may be greater than or equal to the contents of the second compound TD and the fifth compound FD in the same layer. Furthermore, the content of the second compound TD in EML 1342 may be greater than the content of the fifth compound FD in EML 2344. In this case, the exciton energy may be efficiently transferred from the second compound TD to the fifth compound FD via a FRET mechanism. As an example, the content of the second compound TD in the EML 1342 may be, but is not limited to, about 1 wt% to about 70 wt%, about 10 wt% to about 50 wt%, or about 20 wt% to about 50 wt%. In addition, the content of the fourth compound H2 in EML2344 may be about 90 wt% to about 99 wt%, or 95 wt% to about 99 wt%, and the content of the fifth compound FD in EML2344 may be about 1 wt% to about 10 wt%, or about 1 wt% to about 5 wt%.

In one exemplary aspect, when EML2344 is disposed adjacent to HBL 375, fourth compound H2 included in EML2344 together with fifth compound FD may be the same material as HBL 375. In this case, the EML2344 may have a hole blocking function as well as a light emitting function. In other words, EML2344 may act as a buffer layer for blocking holes. In one aspect, HBL 375 may be omitted where EML2344 may be a hole blocking layer as well as a layer of light emitting material.

In another exemplary aspect, when EML2344 is disposed adjacent to EBL 365, fourth compound H2 may be the same material as EBL 365. In this case, the EML2344 may have an electron blocking function as well as a light emitting function. In other words, EML2344 may act as a buffer layer for blocking electrons. In one aspect, EBL 365 may be omitted where EML2344 may be the electron blocking layer as well as the layer of light emitting material.

An OLED with three layers of EMLs will be explained. Fig. 9 is a schematic cross-sectional view illustrating an OLED having three layers of EMLs according to another exemplary aspect of the present disclosure. Fig. 10 is a schematic diagram illustrating a light emitting mechanism by an energy level band gap between light emitting materials according to another exemplary aspect of the present disclosure.

As shown in fig. 9, the OLED D4 includes a first electrode 410 and a second electrode 430 facing each other and a light emitting layer 420 having a single light emitting part disposed between the first electrode 410 and the second electrode 430. The organic light emitting display device 100 (fig. 1) includes a red pixel region, a green pixel region, and a blue pixel region, and the OLED D4 may be disposed in any of the red, green, and blue pixel regions.

In one exemplary aspect, the light emitting layer 420 includes three layers of EMLs 440. The light emitting layer 420 may include at least one of an HTL460 disposed between the first electrode 410 and the EML 440 and an ETL 370 disposed between the second electrode 430 and the EML 440. In addition, the light emitting layer 420 may further include at least one of an HIL 450 disposed between the first electrode 410 and the HTL460 and an EIL 480 disposed between the second electrode 430 and the ETL 470. Alternatively, the light emitting layer 420 may further include an EBL 465 disposed between the HTL460 and the EML 440 and/or an HBL475 disposed between the EML 440 and the ETL 470. The configurations of the first and second electrodes 410 and 430 and the other layers in the light emitting layer 420 except for the EML 440 are substantially the same as the corresponding electrodes and layers in the OLED D1, the OLED D2, and the OLED D3.

The EML 440 includes a first EML (EML1, middle EML, first layer) 442, a second EML (EML2, lower EML, second layer) 444, and a third EML (EML3, upper EML, third layer) 446. EML 1442 is disposed between EBL 465 and HBL475, EML2444 is disposed between EBL 465 and EML 1442, and EML 3446 is disposed between EML 1442 and HBL 475.

EML 1442 contains a second compound (compound 2, first dopant) TD that may be a delayed fluorescence material. Each of the EML2444 and EML 3446 includes a fifth compound (compound 5, a second dopant) FD1 and a seventh compound (compound 7, a third dopant) FD2, respectively, and each of the fifth compound and the seventh compound may be a fluorescent or phosphorescent material. In addition, each of EML 1442, EML2444, and EML 3446 further comprises a first compound (compound 1, host 1) H1, a fourth compound (compound 4, host 2) H2, and a sixth compound (compound 6, host 3) H3, respectively, which may each be a first to third host.

According to this aspect, the singlet energy and the triplet energy of the second compound TD (i.e., delayed fluorescent material) in the EML 1442 may be transferred to the fifth compound FD1 and the seventh compound FD2, i.e., fluorescent or phosphorescent materials, respectively contained in the EML2444 and the EML 3446 disposed adjacent to the EML 1442, through a FRET mechanism. Therefore, final light emission occurs in the fifth compound FD1 and the seventh compound FD2 in EML2444 and EML 3446.

The triplet exciton energy of the second compound TD having a delayed fluorescence characteristic in the EML 1442 is converted up to its own singlet exciton energy by the RISC mechanism, and then the singlet exciton energy of the second compound TD is transferred to the singlet exciton energies of the fifth compound FD1 and the seventh compound FD2 in the EML2444 and the EML 3446 because of the excited singlet level S of the second compound TD₁ ^TDExcited singlet level S higher than fifth compound FD1 and seventh compound FD2₁ ^FD1And S₁ ^FD2Each of (see)See fig. 10). Singlet exciton energy of the second compound TD in EML 1442 is transferred to the fifth compound FD1 and the seventh compound FD2 in EML2444 and EML 3446 disposed adjacent to EML 1442 through a FRET mechanism.

The fifth and seventh compounds FD1 and FD2 in EML2444 and EML 3446 may emit light using singlet exciton energy and triplet exciton energy derived from the second compound TD. The fifth compound FD1 and the seventh compound FD2 may each have a narrower FWHM compared to the second compound TD. Since exciton energy generated at the second compound TD having delayed fluorescence property in the EML 1442 is transferred to the fifth compound FD1 and the seventh compound FD2 in the EML2444 and the EML 3446, super fluorescence may be realized. In particular, the fifth compound FD1 and the seventh compound FD2 may each have a light emission spectrum having a large overlap region with the absorption spectrum of the second compound TD, so that exciton energy of the second compound TD may be efficiently transferred to each of the fifth compound FD1 and the seventh compound FD 2. In this case, substantial light emission occurs in the EML2444 and the EML 3446.

In order to achieve effective light emission in the EML 440, it is necessary to appropriately adjust energy levels between the light emitting materials in the EML 1442, EML2444, and EML 3446. As shown in fig. 10, excited singlet energy levels S of a first compound H1, a fourth compound H2, and a sixth compound H3 (each of which may be a first host to a third host, respectively)₁ ^H1、S₁ ^H2And S₁ ^H3And excited triplet state energy level T₁ ^H1、T₁ ^H2And T₁ ^H3Should be respectively higher than the excited singlet state level S of the second compound TD (which may be a delayed fluorescent material)₁ ^TDAnd excited triplet state energy level T₁ ^TDEach of the above.

In addition, the EML 440 must achieve high luminous efficiency and color purity, and efficiently transfer exciton energy from the second compound TD in EML 1442 (which is converted into an ICT complex state by a RISC mechanism) to the fifth compound FD1 and the seventh compound FD2, which are fluorescent or phosphorescent materials, respectively, in EML2444 and EML 3446. To achieve thisThe excited triplet level T of the second compound TD in the OLED D4, EML 1442₁ ^TDExcited triplet energy level T higher than that of the fifth compound FD1 and the seventh compound FD2₁ ^FD1And T₁ ^FD2Each of the above. Or the excited singlet level S of the second compound TD₁ ^TDAn excited singlet level S that may be higher than the fifth and seventh compounds FD1 and FD2 as fluorescent or phosphorescent materials₁ ^FD1And S₁ ^FD2Each of the above.

In addition, in order to achieve efficient light emission, exciton energy transferred from the second compound TD to each of the fifth compound FD1 and the seventh compound FD2 should not be transferred to the fourth compound H2 and the sixth compound H3. As an example, excited singlet level S of fourth Compound H2 and sixth Compound H3₁ ^H2And S₁ ^H3Each of which may be higher than the excited singlet energy level S of the fifth compound FD1 and the seventh compound FD2, respectively₁ ^FD1And S₁ ^FD2Each of the above.

Each of EML 1442, EML2444, and EML 3446 may include a first compound H1, a fourth compound H2, and a sixth compound H3 (which may each be a first body to a third body), respectively. For example, each of the first compound H1, the fourth compound H2, and the sixth compound H3 may be the same as or different from each other. For example, each of the first compound H1, the fourth compound H2, and the sixth compound H3 may independently include any organic compound having a structure of chemical formulas 1 to 3. The second compound TD may be the same as described above.

The fifth compound FD1 and the seventh compound FD2 may each have a narrow FWHM and have an absorption spectrum having a large overlapping region with the emission spectrum of the second compound TD. The fifth compound FD1 and the seventh compound FD2 may each be a fluorescent or phosphorescent material emitting blue, green, or red light. For example, the fifth compound FD1 and the seventh compound FD2 may each be a fluorescent or phosphorescent material emitting blue, green, or red light as described above.

In one exemplary aspect, each of the contents of the fourth compound H2 and the sixth compound H3 in EML2444 and EML 3446 may be greater than or equal to each of the contents of the fifth compound and the seventh compound in the same layer. Further, the content of the second compound TD in EML 1442 may be greater than each of the contents of the fifth compound FD1 and the seventh compound FD2 in EML2444 and EML 3446. In this case, exciton energy may be efficiently transferred from the second compound to the fifth compound and the seventh compound via a FRET mechanism. As an example, the content of the second compound TD in the EML 1442 may be, but is not limited to, about 1 wt% to about 70 wt%, or about 10 wt% to about 50 wt%, or about 20 wt% to about 50 wt%. Further, the content of the fourth compound H2 and the sixth compound H3 in EML2444 and EML 3446 may each be about 90 wt% to about 99 wt%, or 95 wt% to about 99 wt%, and the content of the fifth compound FD1 and the seventh compound FD2 in EML2444 and EML 3446 may each be about 1 wt% to about 10 wt%, or about 1 wt% to about 5 wt%.

In one exemplary aspect, when the EML2444 is disposed adjacent to the EBL 465, the fourth compound H2 included in the EML2444 along with the fifth compound FD1 may be the same material as the EBL 465. In this case, the EML2444 may have an electron blocking function as well as a light emitting function. In other words, the EML2444 may act as a buffer layer for blocking electrons. In one aspect, the EBL 465 can be omitted where the EML2444 can be an electron blocking layer as well as a layer of light emitting material.

In another exemplary aspect, when EML 3446 is disposed adjacent to HBL475, sixth compound H3, which is included in EML 3446 along with seventh compound FD2, may be the same material as HBL 475. In this case, the EML 3446 may have a hole blocking function as well as a light emitting function. In other words, the EML 3446 may serve as a buffer layer for blocking holes. In one aspect, HBL475 may be omitted where EML 3446 may be a hole blocking layer as well as a layer of light emitting material.

In yet another exemplary aspect, fourth compound H2 in EML2444 may be the same material as EBL 465 and sixth compound H3 in EML 3446 may be the same material as HBL 475. In this aspect, the EML2444 may have an electron blocking function as well as a light emitting function, and the EML 3446 may have a hole blocking function as well as a light emitting function. In other words, each of the EML2444 and EML 3446 may act as a buffer layer for blocking electrons or holes, respectively. In one aspect, EBL 465 and HBL475 may be omitted where EML2444 may be an electron blocking layer and a light emitting material layer, and EML 3446 may be a hole blocking layer and a light emitting material layer.

In another aspect, the OLED may include a plurality of light emitting parts. Fig. 11 is a schematic cross-sectional view illustrating an OLED according to another exemplary aspect of the present disclosure.

As shown in fig. 11, the OLED D5 includes a first electrode 510 and a second electrode 530 facing each other and a light emitting layer 520 having two light emitting parts disposed between the first electrode 510 and the second electrode 530. The organic light emitting display device 100 (fig. 1) includes: a red pixel region, a green pixel region, and a blue pixel region, the OLED D5 may be disposed in any of the red, green, and blue pixel regions. In one exemplary aspect, the OLED D5 may be disposed in a blue pixel region. The first electrode 510 may be an anode, and the second electrode 530 may be a cathode.

The light emitting layer 520 includes a first light emitting portion 620 and a second light emitting portion 720, the first light emitting portion 620 including a first EML (EML1)640, and the second light emitting portion 720 including a second EML (EML2) 740. In addition, the light emitting layer 520 may further include a Charge Generation Layer (CGL)680 disposed between the first and second light emitting portions 620 and 720.

The CGL 680 is disposed between the first and second light emitting parts 620 and 720 such that the first light emitting part 620, the CGL 680, and the second light emitting part 720 are sequentially disposed on the first electrode 510. In other words, the first light emitting part 620 is disposed between the first electrode 510 and the CGL 680, and the second light emitting part 720 is disposed between the second electrode 530 and the CGL 680.

The first luminescent portion 620 includes an EML 1640. The first light emitting portion 620 may further include at least one of a first HTL (HTL1)660 disposed between the first electrode 510 and the EML 1640, an HIL 650 disposed between the first electrode 510 and the HTL 1660, and a first ETL (ETL1)670 disposed between the EML 1640 and the CGL 680. Alternatively, the first light emitting portion 620 may further include a first EBL (EBL1)665 disposed between the HTL 1660 and the EML 1640 and/or a first HBL (HBL1)675 disposed between the EML 1640 and the ETL 1670.

The second light emitting part 720 includes an EML 2740. The second light emitting part 720 may further include at least one of a second HTL (HTL2)760 disposed between the CGL 680 and the EML 2740, a second ETL (ETL2)770 disposed between the EML 2740 and the second electrode 530, and an EIL 780 disposed between the EML 2770 and the second electrode 530. Alternatively, the second light emitting part 720 may further include a second EBL (EBL2)765 disposed between the HTL 2760 and the EML 2740 and/or a second HBL (HBL2)775 disposed between the EML 2740 and the ETL 2770.

The first and second light emitting parts 620 and 720 are connected by a CGL 680. CGL 680 may be a PN junction CGL connecting an N-type CGL (N-CGL)682 and a P-type CGL (P-CGL) 684.

N-CGL 682 is disposed between ETL 1670 and HTL 2760, and P-CGL 684 is disposed between N-CGL 682 and HTL 2760. The N-CGL 682 transports electrons to the EML 1640 of the first light emitting portion 620, and the P-CGL 684 transports holes to the EML 2740 of the second light emitting portion 720. In one exemplary aspect, N-CGL 682 may include any organic compound having the structure of chemical formulas 1 to 3.

In this aspect, each of the EML 1640 and EML 2740 may be a blue, green, or red light emitting material layer. For example, at least one of EML 1640 and EML 2740 comprises a first compound H as a host, a second compound TD as a delayed fluorescent material, and/or a third compound FD as a fluorescent or phosphorescent material. For example, EML 1640 may comprise a first compound, a second compound, and a third compound.

When the EML 1640 includes the first compound H, the second compound TD, and the third compound FD, the content of the first compound H may be greater than the content of the second compound TD, and the content of the second compound TD is greater than the content of the third compound FD. In this case, the exciton energy may be efficiently transferred from the second compound TD to the third compound FD. As an example, the content of the first compound H, the second compound TD, and the third compound FD in the EML 1640 may each be, but is not limited to, about 60 wt% to about 75 wt%, about 20 wt% to about 40 wt%, and about 0.1 wt% to about 5 wt%.

In one exemplary aspect, the EML 2740 may include a first compound H having the structure of chemical formulas 1 to 3 as a host, a second compound TD as a delayed fluorescent material, and/or a third compound FD as a fluorescent or phosphorescent material. Alternatively, the EML 2740 may contain another compound different from at least one of the second compound TD and the third compound FD in the EML 1640, and thus the EML 2740 may emit light different from light emitted from the EML 1640, or may have a light emission efficiency different from that of the EML 1640.

In fig. 11, EML 1640 and EML 2740 each have a single-layer structure. Alternatively, each of the EML 1640 and the EML 2740, which may each include the first to third compounds, may have a double-layer structure (fig. 7) or a triple-layer structure (fig. 9), respectively.

In the OLED D5, singlet exciton energy of the second compound TD of the delayed fluorescent material is transferred to the third compound FD of the fluorescent or phosphorescent material, and final light emission occurs at the third compound. Therefore, the OLED D5 may have excellent luminous efficiency and color purity. In addition, the OLED D5 has a dual stack structure of blue, green, or red light emitting material layers, and the OLED D5 improves its color sense or optimizes its light emitting efficiency.

Fig. 12 is a schematic cross-sectional view illustrating an organic light emitting display device according to another exemplary aspect of the present disclosure. As shown in fig. 12, the organic light emitting display device 800 includes: a substrate 810 defining a first pixel region P1, a second pixel region P2, and a third pixel region P3, a thin film transistor Tr disposed over the substrate 810, and an OLED D disposed over and connected to the thin film transistor Tr. As an example, the first pixel region P1 may be a blue pixel region, the second pixel region P2 may be a green pixel region, and the third pixel region P3 may be a red pixel region.

The substrate 810 may be a glass substrate or a flexible substrate. For example, the flexible substrate may be any one of a PI substrate, a PES substrate, a PEN substrate, a PET substrate, and a PC substrate.

A buffer layer 812 is disposed over the substrate 810, and the thin film transistor Tr is disposed over the buffer layer 812. The buffer layer 812 may be omitted. As shown in fig. 1, the thin film transistor Tr includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and functions as a driving element.

A passivation layer 850 is disposed over the thin film transistor Tr. The passivation layer 850 has a flat top surface and a drain contact hole 852 exposing the drain electrode of the thin film transistor Tr.

The OLED D is disposed over the passivation layer 850, and includes a first electrode 910 connected to a drain electrode of the thin film transistor Tr, and a light emitting layer 920 and a second electrode 930 each sequentially disposed on the first electrode 910. The OLED D is disposed in each of the first, second, and third pixel regions P1, P2, and P3, and emits different light in each pixel region. For example, the OLED D in the first pixel region P1 may emit blue light, the OLED D in the second pixel region P2 may emit green light, and the OLED D in the third pixel region P3 may emit red light.

The first electrode 910 is formed separately for each of the first, second, and third pixel regions P1, P2, and P3, and the second electrode 930 corresponds to the first, second, and third pixel regions P1, P2, and P3, and is integrally formed.

The first electrode 910 may be one of an anode and a cathode, and the second electrode 930 may be the other of the anode and the cathode. In addition, one of the first and second electrodes 910 and 930 is a transmissive (or semi-transmissive) electrode, and the other of the first and second electrodes 910 and 930 is a reflective electrode.

For example, the first electrode 910 may be an anode and may include a transparent conductive oxide layer of a conductive material having a relatively high work function value, i.e., a Transparent Conductive Oxide (TCO). The second electrode 930 may be a cathode and may include a conductive material having a relatively low work function value, i.e., a metallic material layer of a low resistance metal. For example, the first electrode 910 may include any one of ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO, and the second electrode 930 may include Al, Mg, Ca, Ag, an alloy thereof, or a combination thereof.

When the organic light emitting display device 800 is a bottom emission type, the first electrode 910 may have a single layer structure of a transparent conductive oxide layer.

Alternatively, when the organic light emitting display device 800 is a top emission type, a reflective electrode or a reflective layer may be disposed under the first electrode 910. For example, the reflective electrode or reflective layer may include, but is not limited to, Ag or APC alloy. In the top emission type OLED D, the first electrode 910 may have a triple-layered structure of ITO/Ag/ITO or ITO/APC/ITO. In addition, the second electrode 930 is thin so as to have a light transmission (or semi-transmission) characteristic.

A light emitting layer 920 is disposed on the first electrode 910. In one exemplary aspect, the light emitting layer 920 may have a single layer structure of EML. Alternatively, the light emitting layer 920 may include at least one of an HIL, an HTL, and an EBL sequentially disposed between the first electrode 910 and the EML, and/or at least one of an HBL, an ETL, and an EIL sequentially disposed between the EML and the second electrode 930.

In one exemplary aspect, the EML of the light emitting layer 920 in the first pixel region P1 of the blue pixel region may include a first compound H as a host, a second compound as a blue delayed fluorescent material, and/or a third compound as a blue fluorescent or phosphorescent material. The EML of the light emitting layer 920 in the second pixel region P2 of the green pixel region may include the first compound H as a host, the second compound as a green delayed fluorescent material, and/or the third compound as a green fluorescent or phosphorescent material. The EML of the light emitting layer 920 in the third pixel region P3 of the red pixel region may include the first compound H as a host, the second compound as a red delayed fluorescent material, and/or the third compound as a red fluorescent or phosphorescent material. In this case, each EML in the light emitting layer 920 in the first, second, and third pixel regions P1, P2, and P3 may have a single-layer structure, a double-layer structure, or a triple-layer structure.

Alternatively, any EML in the light emitting layer 920 in any one of the first, second, and third pixel regions P1, P2, and P3 may contain an organic compound other than the first to third compounds.

An encapsulation film 870 may be disposed over the second electrode 930 to prevent external moisture from penetrating into the OLED D. The encapsulation film 870 may have, but is not limited to, a three-layer structure of a first inorganic insulating film, an organic insulating film, and a second inorganic insulating film.

A bank layer 860 is disposed on the passivation layer 850 to cover an edge of the first electrode 910. In addition, the organic light emitting display device 800 may have a polarizer to reduce external light reflection. For example, the polarizer may be a circular polarizer. When the organic light emitting display device 800 is a bottom emission type, a polarizer may be disposed under the substrate 810. Alternatively, when the organic light emitting display device 800 is a top emission type, the polarizer may be disposed over the encapsulation film 870.

Fig. 13 is a schematic cross-sectional view illustrating an OLED according to still another exemplary aspect of the present disclosure. As shown in fig. 13, the OLED D6 includes a first electrode 910, a second electrode 930 facing the first electrode 910, and a light emitting layer 920 disposed between the first electrode 910 and the second electrode 930.

The first electrode 910 may be an anode and the second electrode 930 may be a cathode. As an example, the first electrode 910 may be a reflective electrode, and the second electrode 930 may be a transmissive (or semi-transmissive) electrode.

The light emitting layer 920 includes an EML 940. The light emitting layer 920 may include at least one of an HTL 960 disposed between the first electrode 910 and the EML 940 and an ETL 970 disposed between the second electrode 930 and the EML 940. In addition, the light emitting layer may further include at least one of an HIL 950 disposed between the first electrode 910 and the HTL 960 and an EIL 980 disposed between the second electrode 930 and the ETL 970. Alternatively, the light emitting layer 920 may also include an EBL 965 disposed between the HTL 960 and the EML 940 and/or an HBL 975 disposed between the EML 940 and the ETL 970.

In addition, the light emitting layer 920 may further include an auxiliary hole transport layer (auxiliary HTL)962 disposed between the HTL 960 and the EBL 965. The auxiliary HTL 962 may include a first auxiliary HTL 962a in the first pixel region P1, a second auxiliary HTL 962b in the second pixel region P2, and a third auxiliary HTL 962c in the third pixel region P3.

The first auxiliary HTL 962a has a first thickness, the second auxiliary HTL 962b has a second thickness, and the third auxiliary HTL 962c has a third thickness. The first thickness is less than the second thickness, which is less than the third thickness. Therefore, the OLED D6 has a microcavity structure.

Since the first, second, and third auxiliary HTLs 962a, 962b, and 962c have different thicknesses from each other, a distance between the first and second electrodes 910 and 930 in the first pixel region P1 that emits light (blue light) in the first wavelength range is smaller than a distance between the first and second electrodes 910 and 930 in the second pixel region P2 that emits light (green light) in the second wavelength range. Further, the distance between the first electrode 910 and the second electrode 930 in the second pixel region P2 that emits light in the second wavelength range is smaller than the distance between the first electrode 910 and the second electrode 930 in the third pixel region P3 that emits light in the third wavelength range (red light). Therefore, the OLED D6 has improved luminous efficiency.

In fig. 13, the first auxiliary HTL 962a is located in the first pixel region P1. Alternatively, the OLED D6 may implement a microcavity structure without the first auxiliary HTL 962 a. Furthermore, a cover layer may be provided over the second electrode to improve the out-coupling of the light emitted from the OLED D6.

The EML 940 includes a first EML (EML1)942 located in the first pixel region P1, a second EML (EML2)944 located in the second pixel region P2, and a third EML (EML3)946 located in the third pixel region P3. The EML 1942, EML 2944, and EML 3946 may each be blue EML, green EML, and red EML, respectively.

In one exemplary aspect, the EML 1942 located in the first pixel region P1 may include a first compound H that is a host, a second compound TD that is a blue-delayed fluorescent material, and/or a third compound FD that is a blue-fluorescent or phosphorescent material. The EML 2944 located in the second pixel region P2 may include a first compound H that is a host, a second compound TD that is a green delayed fluorescent material, and/or a third compound FD that is a green fluorescent or phosphorescent material. The EML 3946 positioned in the third pixel region P3 may include a first compound H that is a host, a second compound TD that is a red delayed fluorescent material, and/or a third compound FD that is a red fluorescent or phosphorescent material. The first compound H in the EML 1942, EML 2944, and EML 3946 may be any organic compound having a structure of chemical formulas 1 to 3.

When the EML 1942, EML 2944, and EML 3946 include the first compound H, the second compound TD, and the third compound FD, the content of the first compound H may be greater than the content of the second compound TD, and the content of the second compound TD may be greater than the content of the third compound FD. In this case, the exciton energy may be efficiently transferred from the second compound TD to the third compound FD. As an example, the contents of the first compound H, the second compound TD, and the third compound FD in each of the EML 1942, the EML 2944, and the EML 3946 may each be, but are not limited to, about 60 wt% to about 75 wt%, about 20 wt% to about 40 wt%, and about 0.1 wt% to about 5 wt%, respectively.

Although each of the EML 1942, EML 2944, and EML 3946 has a single-layer structure in fig. 13, each of the EML 1942, EML 2944, and EML 3946 may have a double-layer structure (fig. 7) or a triple-layer structure (fig. 9), respectively.

In another exemplary aspect, at least one of the EML 1942, EML 2944, and EML 3946 may include a first compound H, a second compound TD, and a third compound, and the rest of the EML 1942, EML 2944, and EML 3946 may include other organic compounds. In this case, the EML 1942, EML 2944, and EML 3946 having the first to third compounds may have a single-layer structure, a double-layer structure, or a three-layer structure.

For example, the first EML 1942 located in the first pixel region P1 may include a first compound H that is a host, a second compound TD that is a blue-delayed fluorescent material, and/or a third compound FD that is a blue-fluorescent or phosphorescent material. The EML 2944 located in the second pixel region P2 may include a host and a green dopant, and the EML 3946 located in the third pixel region P3 may include a host and a red dopant. The body of EML 2944 and/or EML 3944 may include the first compound H. Each of the green or red dopants may include at least one of a green or red phosphorescent material, a green or red fluorescent material, and a green or red delayed fluorescent material.

The OLEDs D6 emit blue, green, and red light in the first, second, and third pixel regions P1, P2, and P3, respectively, so that the organic light emitting display device 800 (fig. 12) can realize a full-color image.

The organic light emitting display device 800 may further include a color filter layer corresponding to the first, second, and third pixel regions P1, P2, and P3 to improve color purity of light emitted from the OLED D. As an example, the color filter layer may include a first color filter layer (blue color filter layer) corresponding to the first pixel region P1, a second color filter layer (green color filter layer) corresponding to the second pixel region P2, and a third color filter layer (red color filter layer) corresponding to the third pixel region P3.

When the organic light emitting display device 800 is a bottom emission type, a color filter layer may be disposed between the OLED D and the substrate 810. Alternatively, when the organic light emitting display device 800 is a top emission type, the color filter layer may be disposed over the OLED D.

Fig. 14 is a schematic cross-sectional view illustrating an organic light emitting display device according to still another exemplary aspect of the present disclosure. As shown in fig. 14, the organic light emitting display device 1000 includes: a substrate 1010 defining a first pixel region P1, a second pixel region P2, and a third pixel region P3; a thin film transistor Tr disposed over the substrate 1010; an OLED D disposed above the thin film transistor Tr and connected to the thin film transistor Tr, and a color filter layer 1020 corresponding to the first, second, and third pixel regions P1, P2, and P3. As an example, the first pixel region P1 may be a blue pixel region, the second pixel region P2 may be a green pixel region, and the third pixel region P3 may be a red pixel region.

The substrate 1010 may be a glass substrate or a flexible substrate. For example, the flexible substrate may be any one of a PI substrate, a PES substrate, a PEN substrate, a PET substrate, and a PC substrate. The thin film transistor Tr is located above the substrate 1010. Alternatively, a buffer layer may be disposed over the substrate 1010, and the thin film transistor Tr may be disposed over the buffer layer. As shown in fig. 1, the thin film transistor Tr includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode and functions as a driving element.

A color filter layer 1020 is positioned over the substrate 1010. As an example, the color filter layer 1020 may include a first color filter layer 1022 corresponding to the first pixel region P1, a second color filter layer 1024 corresponding to the second pixel region P2, and a third color filter layer 1026 corresponding to the third pixel region P3. The first color filter layer 1022 may be a blue color filter layer, the second color filter layer 1024 may be a green color filter layer, and the third color filter layer 1026 may be a red color filter layer. For example, the first color filter layer 1022 may include at least one of a blue dye or a blue pigment, the second color filter layer 1024 may include at least one of a green dye or a green pigment, and the third color filter layer 1026 may include at least one of a red dye or a red pigment.

A passivation layer 1050 is disposed over the thin film transistor Tr and the color filter layer 1020. The passivation layer 1050 has a flat top surface and a drain contact hole 1052 exposing the drain electrode of the thin film transistor Tr.

The OLED D is disposed over the passivation layer 1050 and corresponds to the color filter layer 1020. The OLED D includes a first electrode 1110 connected to the drain electrode of the thin film transistor Tr, a light emitting layer 1120 and a second electrode 1130 each sequentially disposed on the first electrode 1110. The OLEDs D emit white light in the first, second, and third pixel regions P1, P2, and P3.

The first electrode 1110 is separately formed for each of the first, second, and third pixel regions P1, P2, and P3, and the second electrode 1130 corresponds to and is integrally formed with the first, second, and third pixel regions P1, P2, and P3.

The first electrode 1110 may be one of an anode and a cathode, and the second electrode 1130 may be the other of the anode and the cathode. In addition, the first electrode 1110 may be a transmissive (or semi-transmissive) electrode, and the second electrode 1130 may be a reflective electrode.

For example, the first electrode 1110 may be an anode, and may include a transparent conductive oxide layer of a conductive material having a relatively high work function value, i.e., a Transparent Conductive Oxide (TCO). The second electrode 1130 may be a cathode, and may include a conductive material having a relatively low work function value, i.e., a metallic material layer of a low-resistance metal. For example, the transparent conductive oxide layer of the first electrode 1110 may include any one of ITO, IZO, ITZO, SnO, ZnO, ICO, and AZO, and the second electrode 1130 may include Al, Mg, Ca, Ag, an alloy thereof (e.g., Mg — Ag), or a combination thereof.

The light emitting layer 1120 is disposed on the first electrode 1110. The light emitting layer 1120 includes at least two light emitting portions emitting different colors. Each of the light emitting parts may have a single-layer structure of the EML. Alternatively, each of the light emitting parts may include at least one of a HIL, a HTL, an EBL, a HBL, an ETL, and an EIL. Further, the light emitting layer may further include CGLs disposed between the light emitting portions.

At least one of the at least two light emitting parts may include a first compound H as a host having a structure of chemical formulas 1 to 3, a second compound TD as a delayed fluorescent material, and/or a third compound FD as a fluorescent or phosphorescent material.

A bank layer 1060 is disposed on the passivation layer 1050 to cover an edge of the first electrode 1110. The bank layer 1060 corresponds to each of the first, second, and third pixel regions P1, P2, and P3, and exposes the center of the first electrode 1110. As described above, since the OLED D emits white light in the first, second, and third pixel regions P1, P2, and P3, the light emitting layer 1120 may be formed as a common layer without being separated in the first, second, and third pixel regions P1, P2, and P3. The bank layer 1060 is formed to prevent current from leaking from the edge of the first electrode 1110, and the bank layer 1060 may be omitted.

In addition, the organic light emitting display device 1000 may further include an encapsulation film disposed on the second electrode 1130 to prevent external moisture from penetrating into the OLED D. In addition, the organic light emitting display device 1000 may further include a polarizer disposed under the substrate 1010 to reduce external light reflection.

In the organic light emitting display device 1000 in fig. 14, the first electrode 1110 is a transmissive electrode, the second electrode 1130 is a reflective electrode, and the color filter layer 1020 is disposed between the substrate 1010 and the OLED D. That is, the organic light emitting display device 1000 is a bottom emission type. Alternatively, in the organic light emitting display device 1000, the first electrode 1110 may be a reflective electrode, the second electrode 1130 may be a transmissive electrode (or a semi-transmissive electrode), and the color filter layer 1020 may be disposed over the OLED D.

In the organic light emitting display device 1000, the OLEDs D located in the first, second, and third pixel regions P1, P2, and P3 emit white light, which passes through each of the first, second, and third pixel regions P1, P2, and P3, so that blue, green, and red are respectively displayed in the first, second, and third pixel regions P1, P2, and P3.

The color conversion film may be disposed between the OLED D and the color filter layer 1020. The color conversion films correspond to the first, second, and third pixel regions P1, P2, and P3, and include a blue conversion film, a green conversion film, and a red conversion film, each of which can convert white light emitted from the OLED D into blue, green, and red light, respectively. For example, the color conversion film may comprise quantum dots. Accordingly, the organic light emitting display device 1000 may further enhance its color purity. Alternatively, a color conversion film may replace the color filter layer 1020.

Fig. 15 is a schematic cross-sectional view illustrating an OLED according to still another exemplary aspect of the present disclosure. As shown in fig. 15, the OLED D7 includes a first electrode 1110 and a second electrode 1130 facing each other and a light emitting layer 1120 disposed between the first electrode 1110 and the second electrode 1130. The first electrode 1110 may be an anode, and the second electrode 1130 may be a cathode. For example, the first electrode 1110 may be a transmissive electrode, and the second electrode 1130 may be a reflective electrode.

The light emitting layer 1120 includes a first light emitting portion 1220, a second light emitting portion 1320, and a third light emitting portion 1420, the first light emitting portion 1220 includes a first EML (EML1)1240, the second light emitting portion 1320 includes a second EML (EML2)1340, and the third light emitting portion 1420 includes a third EML (EML3) 1440. Further, the light emitting layer 1120 may further include a first charge generation layer (CGL1)1280 disposed between the first light emitting portion 1220 and the second light emitting portion 1320 and a second charge generation layer (CGL2)1380 disposed between the second light emitting portion 1320 and the third light emitting portion 1420. Accordingly, the first light emitting part 1220, the CGL 11280, the second light emitting part 1320, the CGL 21380, and the third light emitting part 1420 are sequentially disposed on the first electrode 1110.

The first light emitting portion 1220 may further include at least one of a first HTL (HTL1)1260 disposed between the first electrode 1110 and the EML 11240, an HIL 1250 disposed between the first electrode 1110 and the HTL11260, and a first ETL (ETL1)1270 disposed between the EML 11240 and the CGL 11280. Alternatively, the first light emitting portion 1220 may further include a first EBL (EBL1)1265 disposed between the HTL11260 and the EML 11240 and/or a first HBL (HBL1)1275 disposed between the EML 11240 and the ETL 11270.

The second light emitting part 1320 may further include at least one of a second HTL (HTL2)1360 disposed between the CGL 11280 and the EML 21340, and a second ETL (ETL2)1370 disposed between the EML 21340 and the CGL 21380. Alternatively, the second light emitting part 1320 may further include a second EBL (EBL2)1365 disposed between the HTL 21360 and the EML 21340 and/or a second HBL (HBL2)1375 disposed between the EML 21340 and the ETL 21370.

The third light emitting part 1420 may further include at least one of a third HTL (HTL3)1460 disposed between the CGL 21380 and the EML31440, a third ETL (ETL3)1470 disposed between the EML31440 and the second electrode 1130, and an EIL 1480 disposed between the ETL 31470 and the second electrode 1130. Alternatively, the third light emitting part 1420 may further include a third EBL (EBL3)1465 disposed between the HTL 31460 and the EML31440 and/or a third HBL (HBL3)1475 disposed between the EML31440 and the ETL 31470.

The CGL 11280 is disposed between the first and second light emitting portions 1220 and 1320. That is, the first light emitting part 1220 and the second light emitting part 1320 are connected via the CGL 11280. The CGL 11280 may be a PN junction CGL connecting the first N-type CGL (N-CGL1)1282 and the first P-type CGL (P-CGL1) 1284.

An N-CGL 11282 is disposed between the ETL 11270 and the HTL 21360, and a P-CGL 11284 is disposed between the N-CGL 11282 and the HTL 21360. The N-CGL 11282 transports electrons to the EML 11240 of the first light emitting portion 1220, and the P-CGL 11284 transports holes to the EML 21340 of the second light emitting portion 1320.

The CGL 21380 is disposed between the second light emitting part 1320 and the third light emitting part 1420. That is, the second light emitting portion 1320 and the third light emitting portion 1420 are connected via the CGL 21380. The CGL 21380 may be a PN junction CGL connecting the second N-type CGL (N-CGL2)1382 and the second P-type CGL (P-CGL2) 1384.

N-CGL 21382 is disposed between ETL 21370 and HTL 31460, and P-CGL 21384 is disposed between N-CGL 21382 and HTL 31460. The N-CGL 21382 transports electrons to the EML 21340 of the second light emitting part 1320, and the P-CGL 21384 transports holes to the EML31440 of the third light emitting part 1420. In one exemplary aspect, at least one of N-CGL 11282 and N-CGL 21382 may comprise any organic compound having the structure of formulae 1 to 3.

In this aspect, one of the first, second, and third EMLs 1240, 1340, and 1440 may be a blue EML, another of the first, second, and third EMLs 1240, 1340, and 1440 may be a green EML, and a third of the first, second, and third EMLs 1240, 1340, and 1440 may be a red EML.

As an example, EML 11240 may be a blue EML, EML 21340 may be a green EML, and EML31440 may be a red EML. Alternatively, EML 11240 may be a red EML, EML 21340 may be a green EML, and EML31440 may be a blue EML. Hereinafter, the OLED D7 in which the EML 11240 is a blue EML, the EML 21340 is a green EML, and the EML31440 is a red EML will be described.

As described below, at least one of EML 11240, EML 21340, and EML31440 may comprise a first compound H, a second compound TD, and/or a third compound FD. The EMLs 1240, 1340, and 1440 including the first to third compounds may have a single layer structure, a double layer structure, or a triple layer structure.

The EML 11240 may include a first compound H as a host, which may be an organic compound having a structure of chemical formulas 1 to 3, a second compound TD that is a blue delayed fluorescent material, and/or a third compound FD that is a blue fluorescent or phosphorescent material. Alternatively, the EML 11240 may contain a host and other blue dopants. The host may include a first compound, and the other blue dopant may include at least one of a blue phosphorescent material, a blue fluorescent material, and a blue delayed fluorescent material.

The EML 21340 may include a first compound H as a host, which may be an organic compound having a structure of chemical formulas 1 to 3, a second compound TD that is a green delayed fluorescent material, and/or a third compound FD that is a green fluorescent or phosphorescent material. Alternatively, EML 21340 may contain a host and other green dopants. The host may include a first compound, and the other green dopant may include at least one of a green phosphorescent material, a green fluorescent material, and a green delayed fluorescent material.

The EML31440 may include a first compound H as a host, which may be an organic compound having a structure of chemical formulas 1 to 3, a second compound TD that is a red delayed fluorescent material, and/or a third compound FD that is a red fluorescent or phosphorescent material. Alternatively, the EML31440 may contain a host and other red dopants. The host may include a first compound, and the other red dopant may include at least one of a red phosphorescent material, a red fluorescent material, and a red delayed fluorescent material.

When the EML 11240, the EML 21340, and the EML31440 each include the first compound H, the second compound TD, and the third compound FD, the content of the first compound H may be greater than the content of the second compound TD, and the content of the second compound TD may be greater than the content of the third compound FD. In this case, the exciton energy may be efficiently transferred from the second compound TD to the third compound FD. As an example, the contents of the first compound H, the second compound TD, and the third compound FD in each of the EML 11240, the EML 21340, and the EML31440 may each be, but are not limited to, about 60 wt% to about 75 wt%, about 20 wt% to about 40 wt%, and about 0.1 wt% to about 5 wt%, respectively.

The OLED D7 emits white light in each of the first, second, and third pixel regions P1, P2, and P3, the white light passing through the color filter layer 1020 disposed in the first, second, and third pixel regions P1, P2, and P3, respectively (fig. 14). Therefore, the OLED D7 can realize a full-color image.

Fig. 16 is a schematic cross-sectional view illustrating an OLED according to still another exemplary aspect of the present disclosure. As shown in fig. 16, the OLED D8 includes a first electrode 1110 and a second electrode 1130 facing each other, and a light emitting layer 1120A disposed between the first electrode 1110 and the second electrode 1130. The first electrode 1110 may be an anode, and the second electrode 1130 may be a cathode. For example, the first electrode 1110 may be a transmissive electrode, and the second electrode 1130 may be a reflective electrode.

The light emitting layer 1120A includes a first light emitting portion 1520, a second light emitting portion 1620, and a third light emitting portion 1720, the first light emitting portion 1520 includes an EML 11540, the second light emitting portion 1620 includes an EML 21640, and the third light emitting portion 1720 includes an EML 31740. Further, the light emitting layer 1120A may further include a CGL 11580 disposed between the first light emitting portion 1520 and the second light emitting portion 1620 and a CGL 21680 disposed between the second light emitting portion 1620 and the third light emitting portion 1720. Accordingly, the first light emitting portion 1520, the CGL 11580, the second light emitting portion 1620, the CGL 21680, and the third light emitting portion 1720 are sequentially disposed on the first electrode 1110.

The first light emitting portion 1520 may further include at least one of an HTL 11560 disposed between the first electrode 1110 and the EML 11540, an HIL 1550 disposed between the first electrode 1110 and the HTL 11560, and an ETL 11570 disposed between the EML 11540 and the CGL 11580. Alternatively, the first luminescent portion 1520 may further include an EBL 11565 disposed between the HTL 11560 and the EML 11540 and/or an HBL 11575 disposed between the EML 11540 and the ETL 11570.

The EML 21640 of the second light emitting part 1620 includes a lower EML 1642 and an upper EML 1644. A lower EML 1642 is positioned adjacent to the first electrode 1110 and an upper EML 1644 is also positioned adjacent to the second electrode 1130. Further, the second light emitting part 1620 may further include at least one of an HTL 21660 disposed between the CGL 11580 and the EML 21640, and an ETL 21670 disposed between the EML 21640 and the CGL 21680. Alternatively, the second light emitting part 1620 may further include an EBL 21665 disposed between the HTL 21660 and the EML 21640 and/or an HBL 21675 disposed between the EML 21640 and the ETL 21670.

The third light emitting portion 1720 may further include at least one of an HTL 31760 disposed between the CGL 21680 and the EML 31740, an ETL 31770 disposed between the EML 31740 and the second electrode 1130, and an EIL 1780 disposed between the ETL 31770 and the second electrode 1130. Alternatively, the third light emitting part 1720 may further include an EBL 31765 disposed between the HTL 31760 and the EML 31740 and/or an HBL 31775 disposed between the EML 31740 and the ETL 31770.

The CGL 11580 is disposed between the first and second light emitting portions 1520 and 1620. That is, the first light emitting portion 1520 and the second light emitting portion 1620 are connected via the CGL 11580. CGL 11580 may be a PN junction CGL that connects N-CGL 11582 and P-CGL 11584. An N-CGL 11582 is disposed between the ETL 11570 and the HTL 21660, and a P-CGL 11584 is disposed between the N-CGL 11582 and the HTL 21660.

The CGL 21680 is disposed between the second light emitting portion 1620 and the third light emitting portion 1720. That is, the second light emitting portion 1620 and the third light emitting portion 1720 are connected via the CGL 21680. The CGL 21680 may be a PN junction CGL linking the N-CGL 21682 and the P-CGL 21684. An N-CGL 21682 is disposed between the ETL 21670 and the HTL 31760, and a P-CGL 21684 is disposed between the N-CGL 21682 and the HTL 31760. In one exemplary aspect, at least one of the N-CGL 11582 and N-CGL 21682 may include any organic compound having the structure of chemical formulas 1 to 3.

As described below, at least one of EML 11540, EML 21640, and EML 31740 may comprise a first compound H, a second compound TD, and/or a third compound FD. The EMLs 1540, 1640, and 1740 including the first to third compounds may have a single layer structure, a double layer structure, or a triple layer structure.

In this aspect, each of EML 11540 and EML 31740 may be a blue EML. In one exemplary aspect, each of the EML 11540 and EML 31740 may include a first compound H that is a host and a second compound TD that is a blue-delayed fluorescent material and/or a third compound FD that is a blue fluorescent or phosphorescent material. Alternatively, at least one of EML 11540 and EML 31740 may include a host and other blue dopants. The host may include a first compound, and the other blue dopant may include at least one of a blue phosphorescent material, a blue fluorescent material, and a blue delayed fluorescent material. The first to third compounds in one of the EML 11540 and EML 31740 may be the same as or different from the host and the blue dopant in the other of the EML 11540 and EML 31740. As an example, the dopants in EML 11540 may differ from the dopants in EML 31740 in terms of luminous efficiency and/or luminous wavelength.

One of the lower EML 1642 and the upper EML 1644 in the EML 21640 may be a green EML, and the other of the lower EML 1642 and the upper EML 1644 in the EML 21640 may be a red EML. The green EML and the red EML are sequentially disposed to form an EML 21640.

In one exemplary aspect, the lower EML 1642, which is a green EML, may include a first compound H that is a host, a second compound TD that is a green delayed fluorescent material, and/or a third compound FD that is a green fluorescent or phosphorescent material. Alternatively, the lower EML 1642, which is a green EML, may contain a host and other green dopants. The host may include a first compound H, and the other green dopant may include at least one of a green phosphorescent material, a green fluorescent material, and a green delayed fluorescent material.

In addition, the upper EML 1644, which is a red EML, may include a first compound H that is a host, a second compound TD that is a red delayed fluorescent material, and/or a third compound FD that is a red fluorescent or phosphorescent material. Alternatively, the upper EML 1644, which is a red EML, may contain a host and other red dopants. The host may include a first compound H, and the other red dopant may include at least one of a red phosphorescent material, a red fluorescent material, and a red delayed fluorescent material.

When each of the EML 11540, EML 21640, and EML 31740 includes the first compound H, the second compound TD, and the third compound FD, the content of the first compound H may be greater than the content of the second compound TD, and the content of the second compound TD may be greater than the content of the third compound FD. In this case, the exciton energy may be efficiently transferred from the second compound TD to the third compound FD. As an example, the contents of the first compound H, the second compound TD, and the third compound FD in each of the EML 11540, the EML 21640, and the EML 31740 may each be, but are not limited to, about 60 wt% to about 75 wt%, about 20 wt% to about 40 wt%, and about 0.1 wt% to about 5 wt%, respectively.

The OLED D8 emits white light in each of the first, second, and third pixel regions P1, P2, and P3, the white light passing through the color filter layer 1020 disposed in the first, second, and third pixel regions P1, P2, and P3, respectively (fig. 14). Therefore, the OLED D8 can realize a full-color image.

In fig. 16, the OLED D8 has a triple stack structure including first to third light emitting parts 1520, 1620 and 1720 including EML 11540 and EML 31740 as blue EMLs. Alternatively, the OLED D8 may have a double stack structure in which one of the first and third light emitting parts 1520 and 1720, each including the EML 11540 and EML 31740, which are blue EMLs, is omitted.

Synthesis example 1: synthesis of Compound 1-1

(1) Synthesis of intermediate B

Compound A (4.48g, 0.013mol), carbazole (2.0g, 0.012mol) and K dissolved in toluene (60mL)₃PO₄Placed in a reactor and the solution was then stirred under a nitrogen atmosphere for 20 minutes. CuI (460mg, 20 mol%) and (. + -.) -trans-1, 2-diaminocyclohexane (DACH, 0.72mL, 50 mol%) were added to the reactor, and the solution was stirred at 110 ℃ for 8 hours. After cooling the temperature to room temperature, the reaction solvent was removed, and then the obtained crude product was purified by column chromatography to obtain intermediate B (1.9g, yield: 42%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.13(d，J＝7.9Hz，2H)，8.02(d，J＝2.4Hz，1H)，7.89(d，J＝8.5Hz，1H)，7.55(dd，J＝8.5，2.7Hz，1H)，7.42(ddd，J＝8.2，7.1，0.9Hz，3H)，7.37(d，J＝8.2Hz，3H)，7.33-7.28(m，2H)，3.94(s，3H).

(2) Synthesis of intermediate c

LiAlH dissolved in THF (10mL) under a nitrogen atmosphere₄(0.22g, 0.006mol) was placed in a reactor and the solution was cooled to 0 ℃. Intermediate B (2.0g, 0.005mol) dissolved in THF (15ML) was slowly added dropwise to the solution. After stirring at the same temperature for 20 minutes, the solution was extracted with ethyl acetate to remove the solvent. The obtained crude product was purified by column chromatography to obtain intermediate C (1.7g, yield: 92%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.13(dt，J＝7.9，1.0Hz，2H)，7.75(d，J＝8.2Hz，1H)，7.73(d，J＝2.4Hz，1H)，7.43-7.35(m，5H)，7.31-7.26(m，2H)，4.84(d，J＝6.1Hz，2H)，2.05(t，J＝6.1Hz，1H).

(3) Synthesis of intermediate D

Intermediate C (1.8g, 0.005mol) and KOH (2.3g, 0.041mol) dissolved in dichloromethane (15mL) were placed in a reactor and then the temperature was cooled to 0 ℃ with stirring. P-toluene-sulfonyl chloride (1.17g, 0.006mol) dissolved in dichloromethane (10mL) was slowly added dropwise to the reaction solution. After stirring at the same temperature for 20 minutes, the reaction mixture was stirred at room temperature for 4 hours again, and then CH was used₂Cl₂Extraction to remove the solvent. The obtained product was purified by column chromatography to obtain intermediate D (2.2g, yield: 85%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.13(d，J＝7.6Hz，2H)，7.81(d，J＝8.2Hz，2H)，7.73(d，J＝8.5Hz，1H)，7.54(d，J＝2.4Hz，1H)，7.44-7.38(m，3H)，7.33-7.29(m，4H)，7.29-7.27(m，2H)，5.23(s，2H)，2.35(s，3H).

(4) Synthesis of Compound 1-1

1H-benzo [ d ] dissolved in DMF (20mL)]Imidazole-2-thiol (0.5g, 0.003mol), CuI (63mg, 10 mol%) and Cs₂CO₃(2.17g, 0.007mol) was placed in a reactor, and the solution was stirred under a nitrogen atmosphere for 20 minutes. Intermediate D (1.68g, 0.003mol) and L-proline (77mg, 20 mol%) dissolved in DMF (20mL) were slowly added dropwise to the reaction solution. After stirring at 160 ℃ for 8 h, the reactor was cooled to room temperature and the solution was then extracted with EtOAc to remove the solvent. The obtained crude product was purified by column chromatography to obtain compound 1-1(1.2g, yield: 89%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.18-8.14(m，2H)，8.07(d，J＝8.5Hz，1H)，7.91-7.86(m，1H)，7.82-7.77(m，1H)，7.68(dd，J＝8.5，2.1Hz，1H)，7.61(d，J＝2.1Hz，1H)，7.47-7.41(m，4H)，7.39-7.35(m，2H)，7.34-7.29(m，2H)，4.10(s，2H).

Synthesis example 2: synthesis of Compound 1-2

(1) Synthesis of intermediate E

Compound a (4.50g, 0.013mol) and 9H-3, 9' -bicarbazole (4.0g, 0.012mol) were reacted in the same manner as synthesis of intermediate B to finally obtain intermediate E (3.0g, yield: 46%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.29-8.27(m，1H)，8.20-8.16(m，2H)，8.12-8.10(m，1H)，7.95(d，J＝8.5Hz，1H)，7.64(dd，J＝8.2，2.6Hz，1H)，7.56(dd，J＝2.1，1.2Hz，2H)，7.50-7.48(m，1H)，7.45-7.37(m，6H)，7.36-7.27(m，3H)，3.98(s，3H).

(2) Synthesis of intermediate F

Intermediate E (2.0g, 0.004mol) was used in the same manner as the synthesis of intermediate C to finally obtain intermediate F (1.6g, yield: 84%) as a white solid.

¹H NMR(500MHz，CDCl3)：δ(ppm)8.29-8.26(m，1H)，8.18(d，J＝7.6Hz，2H)，8.10(d，J＝7.6Hz，1H)，7.84-7.79(m，2H)，7.59-7.52(m，2H)，7.50-7.37(m，7H)，7.34-7.27(m，3H)，4.88(d，J＝6.1Hz，2H)，2.12(t，J＝6.1Hz，1H).

(3) Synthesis of intermediate G

Intermediate F (2.2G, 0.004mol) was used in the same manner as the synthesis of intermediate D to finally obtain intermediate G (2.5G, yield: 88%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.28(d，J＝1.5Hz，1H)，8.19(d，J＝7.9Hz，2H)，8.11(d，J＝7.6Hz，1H)，7.87-7.84(m，2H)，7.82(d，J＝8.2Hz，1H)，7.68(d，J＝2.4Hz，1H)，7.58-7.54(m，1H)，7.53-7.29(m，13H).

(4) Synthesis of Compound 1-2

1H-benzo [ d ] imidazole-2-thiol (0.5G, 0.003mol) and intermediate G (2.23G, 0.003mol) were reacted in the same manner as in the synthesis of Compound 1-1 to finally obtain Compound 1-2(1.6G, yield: 85%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.30(d，J＝1.8Hz，1H)，8.20-8.16(m，2H)，8.15-8.10(m，2H)，7.93-7.88(m，1H)，7.83-7.78(m，1H)，7.76(dd，J＝8.5，2.4Hz，1H)，7.69(d，J＝2.1Hz，1H)，7.62(d，J＝8.5Hz，1H)，7.57(dd，J＝8.7，2.0Hz，1H)，7.53-7.47(m，2H)，7.43-7.37(m，6H)，7.36-7.33(m，1H)，7.32-7.26(m，2H)，4.14(s，2H).

Synthesis example 3: synthesis of Compounds 2-5

(1) Synthesis of intermediate I

Compound H (10.0g, 0.031mol), 1H-benzo [ d ] dissolved in DMF (60mL) under nitrogen atmosphere]Imidazole-2-thiol (4.6g, 0.031mol), FeCl₃(0.5g, 0.003mol) and Cs₂CO₃(20g, 0.061mol) was placed in a reactor. After the solution was stirred at 160 ℃ for 24 hours, AcOH (10mL) was added dropwise to the solution, and then the solution was stirred at the same temperature for 2 hours. The reactor was cooled to room temperature and the solution was extracted with dichloromethane to remove the solvent. The obtained crude product was purified by column chromatography to obtain intermediate I (6.0g, yield: 59%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.61-8.59(d，J＝8.9Hz，1H)，8.48-8.47(d，J＝8.6Hz，1H)，7.78-7.77(d，J＝7.4Hz，1H)，7.75-7.74(d，J＝1.8Hz，1H)，7.68-8.65(dd，J＝8.6，1.8Hz，1H)，7.52-7.44(m，2H).

(2) Synthesis of intermediate J

Intermediate I (0.6g, 0.0018mol), carbazole (0.36g, 0.0022mol) and K dissolved in toluene (30mL) were added₂CO₃Put into a reactorThen, the solution was stirred under a nitrogen atmosphere for 30 minutes. Reacting tris (dibenzylideneacetone) dipalladium (0) (Pd)₂(dba)₃7.2mg, 2 mol%) and tri-tert-butylphosphine (4.4mg, 4 mol%) were added to the reactor, and the solution was stirred at 110 ℃ for 24 hours. After cooling the temperature to room temperature, the reaction solvent was removed, and then the obtained crude product was purified by column chromatography to obtain intermediate J (0.26g, yield: 35%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.89-8.87(d，J＝8.6Hz，1H)，8.69-8.68(d，J＝7.0Hz，1H)，8.17-8.16(d，.J＝8.0Hz，2H)，7.86-7.81(m，3H)，7.58-7.57(d，J＝8.3Hz，2H)，7.56-7.52(td，J＝7.7，1.4Hz，1H)，7.52-7.47(m，3H)，7.39-7.36(t，J＝7.3Hz，2H).

(3) Synthesis of Compounds 2-5

Intermediate J (0.39g, 0.93mmol) dissolved in THF (60mL) was placed in the reactor under nitrogen atmosphere, and the solution was cooled to-78 ℃. 1.0M phenylmagnesium bromide (PhMgBr, 3.75mL) was slowly added dropwise to the reaction solution. After stirring at room temperature for 6 hours, the solution was extracted with diethyl ether to remove the solvent. Dissolving the reaction mixture in CH₃COOH (10mL), then HCl (2mL) was slowly added dropwise to the mixture. The solution was stirred at room temperature for 1 hour with NaHCO₃Neutralizing with aqueous solution, and then neutralizing with CH₂Cl₂And (4) extracting. After removing the solvent, the obtained crude product was purified by column chromatography to obtain compound 2-5(0.2g, yield: 40%) as a white solid.

¹H NMR(500MHz，CDCl₃)：δ(ppm)8.15-8.13(d，J＝7.9Hz，2H)，7.74-7.72(d，J＝7.6Hz，1H)，7.70-7.69(d，.J＝2.2Hz，1H)，7.49-7.42(m，7H)，7.40-7.37(t，J＝7.6Hz，4H)，7.33-7.30(t，J＝7.3Hz，2H)，7.21-7.18(m，2H)，7.00-6.99(d，J＝7.7Hz，4H)，6.85-6.82(t，J＝8.0Hz，1H)，5.53-5.51(d，J＝8.3Hz，1H).

Synthesis example 4: synthesis of Compounds 2-17

(1) Synthesis of intermediate K

Intermediate I (0.6g, 0.0018mol) and 9, 9-diphenylacridine (0.73g, 0.0022mol) were reacted in the same manner as in the synthesis of intermediate J to finally obtain intermediate K (0.44g, yield: 42%) as a white solid.

(2) Synthesis of Compounds 2-17

Intermediate K (0.44g, 0.75mol) and 1.0M PhMgBr (3.0mL) were reacted in the same manner as in the synthesis of compound 2-5 to finally obtain compound 2-17(0.26g, yield: 48%) as a white solid.

Experimental example 1: measurement of energy level

Evaluation of the HOMO level, LUMO level, and energy band gap (E) between the HOMO level and LUMO level of the compound synthesized in the synthesis example_g) Excited singlet level (S)₁) Excited triplet energy level (T)₁) And a photoluminescence peak (PL peak). The results of the simulation evaluation are shown in table 1 below, and the results of the experiment as a coated film in a solution state are shown in table 2 below.

Table 1: energy level simulation test (DFT calculation)

Chemical article	HOMO(eV)	LUMO(eV)	Eg(eV)	S₁(eV)	T₁(eV)
						1-1	-5.53	-1.16	4.37	3.81	3.18
1-2	-5.23	-1.30	3.93	3.55	3.15
						2-5	-5.49	-0.94	3.55	3.93	3.18
2-17	-5.17	-0.94	4.23	3.50	3.33

Table 2: energy level of organic compound

As shown in tables 1 and 2, all the organic compounds synthesized in the synthesis examples have appropriate HOMO levels, LUMO levels, energy band gaps, and excited singlet and triplet energies for the light emitting layer. In particular, consider S₁And T₁With a very high excited triplet level and is suitable for hosts in EMLs and as materials for ETLs and HBLs. In addition, all compounds emit light in the blue wavelength band.

Example 1 (ex.1): fabrication of OLEDs

An OLED was fabricated in which compound 1-1 was applied into the host of an EML. The ITO-attached glass substrate was washed with UV ozone, loaded into a vapor system, and then transferred to a vacuum deposition chamber to deposit additional layers on the substrate. In the following orderAt a deposition rate of 10^-7The organic layer was deposited by evaporation from a heated boat under a support.

Anode (ITO, 50 nm); HIL (HAT-CN, 7 nm); HTL (TAPC, 50 nm); EBL (DCDPA, 10 nm); EML (compound 1-1 (host) by weight) blue delayed fluorescent material TczTrz (dopant) 70:30, 30 nm; HBL (TSPO1, 5 nm); ETL (TPBi, 25 nm); EIL (LiF, 1.5 nm); and a cathode (Al, 100 nm).

Then, a capping layer (CPL) was deposited over the cathode, and the device was encapsulated by glass. After deposition of the light emitting layer and the cathode, the OLED was transferred from the deposition chamber to a drying oven to form a film, and then encapsulated using a UV curable epoxy and a moisture absorbent.

Examples 2 to 3(ex.2 to ex.3): preparation of OLEDsMake

An OLED was manufactured using the same material as example 1, except that compound 1-2(ex.2) or compound 2-5(ex.3) was applied to the EML as a host instead of compound 1-1.

Comparative example 1 (ref.1): fabrication of OLEDs

An OLED was manufactured using the same material as example 1, except that mCBP (ref.1) was applied to the EML as a host instead of compound 1-1.

Experimental example 2: measurement of the luminescence characteristics of OLEDs

Will have a thickness of 9mm manufactured by Ex.1 to Ex.3 and Ref.1²Each OLED of the light emitting area was connected to an external power source, and then the light emitting characteristics of all diodes were evaluated at room temperature using a constant current source (KEITHLEY) and a photometer PR 650. In particular, the measurement is at 10mA/cm²Current density of (d), current efficiency (cd/A), power efficiency (lm/W), external quantum efficiency (EQE,%), maximum EQE (EQE)_max) And CIE color coordinates. The results are shown in table 3 below.

Table 3: luminescence characteristics of OLEDs

Sample (I)	Main body	V	cd/A	1m/W	EQE	EQE_max	CIE(x，y)
								Ref.1	mCBP	4.0	25.8	20.4	14.7	22.8	(0.162，0.289)
Ex.1	1-1	4.1	27.5	21.2	15.3	23.0	(0.163，0.298)
								Ex.2	1-2	4.2	27.0	19.5	15.0	23.8	(0.164，0.299)
Ex.3	2-5	3.7	30.1	25.8	15.7	22.0	(0.170，0.333)

As shown in table 3, the OLEDs in ex.1 to ex.3 showed comparable or slightly lower driving voltages, but enhanced their current efficiency, power efficiency and EQE up to 16.7%, 26.5% and 6.8%, respectively, compared to the OLED in ref.1 using mCBP as a host.

The present disclosure discloses the following solutions:

1. an organic compound having a structure of the following chemical formula 1:

[ chemical formula 1]

2. The organic compound of item 1, wherein the fused heteroaromatic group is unsubstituted, selected from C₁-C₂₀Alkyl radical, C₆-C₂₀Aryl radical, C₃-C₂₀Heteroaryl groups and combinations thereof, or forms a spiro ring structure with the fluorene or xanthene ring.

3. The organic compound of item 1, wherein the fused heteroaromatic group is selected from the group consisting of a carbazolyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety, and a phenoAn oxazinyl moiety.

4. The organic compound of item 1, wherein the fused heteroaromatic group is unsubstituted or is selected from C₁-C₁₀Alkyl, phenyl, carbazolyl and combinations thereof, or forms a spiro ring structure with the xanthene ring, and R₄And R₅Each unsubstituted or substituted by C₁-C₁₀Alkyl, phenyl, and combinations thereof, or R₄And R₅A fluorene ring is formed.

5. The organic compound according to item 1, wherein Z is S.

6. The organic compound according to item 1, wherein the organic compound includes any one having a structure of chemical formula 2 described in the specification.

7. The organic compound according to item 1, wherein the organic compound includes any one having a structure of chemical formula 3 described in the specification.

8. An organic light emitting diode comprising:

a first electrode;

a second electrode facing the first electrode; and

a light emitting layer disposed between the first electrode and the second electrode,

wherein the light emitting layer includes an organic compound having a structure of the following chemical formula 1:

[ chemical formula 1]

Wherein R is₆Selected from hydrogen, unsubstitutedOr substituted C₁-C₃₀Alkyl, unsubstituted or substituted C₆-C₃₀Aromatic radical and unsubstituted or substituted C₃-C₃₀A heteroaromatic group.

9. The organic light-emitting diode of item 8, wherein the fused heteroaromatic group is unsubstituted, selected from C₁-C₂₀Alkyl radical, C₆-C₂₀Aryl radical, C₃-C₂₀Heteroaryl groups and combinations thereof, or forms a spiro ring structure with the fluorene or xanthene ring.

10. The organic light-emitting diode of item 8, wherein the fused heteroaromatic group is selected from the group consisting of a carbazolyl moiety, an acridinyl moiety, a dihydroacridinyl moiety, a phenazinyl moiety, and a phenoAn oxazinyl moiety.

11. The organic light-emitting diode of item 8, wherein the fused heteroaromatic group is unsubstituted or is selected from C₁-C₁₀Alkyl, phenyl and carbazolyl groups and combinations thereof, or form a spiro ring structure with the xanthene ring, and R₄And R₅Each unsubstituted or substituted by C₁-C₁₀Alkyl, phenyl, and combinations thereof, or R₄And R₅A fluorene ring is formed.

12. The organic light-emitting diode according to item 8, wherein the light-emitting layer comprises at least one electron transport layer disposed between the first electrode and the second electrode, and wherein the at least one electron transport layer comprises the organic compound.

13. The organic light-emitting diode according to item 8, wherein the light-emitting layer comprises at least one hole blocking layer disposed between the first electrode and the second electrode, and wherein the at least one hole blocking layer comprises the organic compound.

14. The organic light-emitting diode according to item 8, wherein the light-emitting layer comprises a first light-emitting material layer provided between the first electrode and the second electrode, and wherein the first light-emitting material layer contains the organic compound.

15. The organic light-emitting diode according to item 14, wherein the first luminescent material layer comprises a first compound and a second compound, wherein an excited triplet level of the first compound is higher than an excited triplet level of the second compound, and wherein the first compound comprises the organic compound.

16. The organic light-emitting diode according to item 15, wherein the first luminescent material layer further comprises a third compound.

17. The organic light-emitting diode of item 16, wherein the excited singlet level of the third compound is lower than the excited singlet level of the second compound.

18. The organic light-emitting diode according to item 15, further comprising a second light-emitting material layer provided between the first electrode and the first light-emitting material layer or between the first light-emitting material layer and the second electrode,

wherein the second light emitting material layer includes a fourth compound and a fifth compound.

19. The organic light-emitting diode of item 18, wherein the fourth compound comprises the organic compound.

20. The organic light-emitting diode according to item 18, further comprising a third light-emitting material layer provided opposite to the second light-emitting material layer with respect to the first light-emitting material layer,

wherein the third light emitting material layer comprises a sixth compound and a seventh compound.

21. The organic light-emitting diode of item 20, wherein at least one of the fourth compound and the sixth compound comprises the organic compound.

22. The organic light-emitting diode according to item 8, wherein the light-emitting layer comprises a first light-emitting unit disposed between the first electrode and the second electrode, a second light-emitting unit disposed between the first light-emitting unit and the second electrode, and a charge generation layer disposed between the first light-emitting unit and the second light-emitting unit, and

wherein at least one of the first light emitting unit and the second light emitting unit comprises the organic compound.

23. An organic light emitting device comprising:

a substrate; and

the organic light emitting diode according to any one of items 8 to 22 disposed over the substrate.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims.

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Organic compound, organic light emitting diode including the same, and organic light emitting device including the same

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