阅读说明：本技术 有机电致发光器件和用于有机电致发光器件的多环化合物 (Organic electroluminescent device and polycyclic compound for organic electroluminescent device ) 是由 坂本直也 于 2020-08-05 设计创作，主要内容包括：提供了一种有机电致发光器件和用于有机电致发光器件的多环化合物。所述有机电致发光器件包括：第一电极；第二电极,设置在第一电极上；以及至少一个有机层,设置在第一电极与第二电极之间。其中,所述至少一个有机层包括多环化合物,多环化合物具有包括n,n’-联咔唑部分的核心结构以及在核心结构外部的至少一个可选地取代的咔唑基,核心结构的取代或未取代的咔唑基分别取代在n,n’-联咔唑部分的n±1位处的碳原子之中的任一个以及n,n’-联咔唑部分的n’±1位处的碳原子之中的任一个处；并且n和n’彼此独立地为1至4的整数(其中,n±1和n’±1不为0)。(Provided are an organic electroluminescent device and a polycyclic compound for the organic electroluminescent device. The organic electroluminescent device includes: a first electrode; a second electrode disposed on the first electrode; and at least one organic layer disposed between the first electrode and the second electrode. Wherein the at least one organic layer comprises a polycyclic compound having a core structure comprising an n, n '-bicarbazole moiety and at least one optionally substituted carbazolyl group external to the core structure, the substituted or unsubstituted carbazolyl group of the core structure being substituted at any one of carbon atoms at the n + -1 position of the n, n' -bicarbazole moiety and at any one of carbon atoms at the n '+ -1 position of the n, n' -bicarbazole moiety, respectively; and n 'are independently an integer of 1 to 4 (wherein n + -1 and n' + -1 are not 0).)

1. A polycyclic compound represented by formula 1 below:

[ formula 1]

In the formula 1, the first and second groups,

l is a direct bond;

R₁to R₄Each independently of the other, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally bonded to an adjacent group to form a ring;

m1 to m4 are each, independently of one another, an integer from 1 to 4;

Z₁to Z₈Each independently of the others, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atomsA substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally bonded to an adjacent group to form a ring; and is

Z₁And Z₂、Z₂And Z₃And Z₃And Z₄Is represented by the following formula 2-1, and Z₅And Z₆、Z₆And Z₇And Z₇And Z₈At least one pair of them is represented by the following formula 2-2:

in the formulae 2-1 and 2-2,

R₁₁and R₁₂Each independently of the other, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally bonded to an adjacent group to form a ring;

m11 and m12 are each, independently of the other, an integer from 1 to 4; and is

Ar₁And Ar₂Each independently of the other, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

2. The polycyclic compound of claim 1, wherein formula 1 has a symmetrical structure about L.

3. The polycyclic compound of claim 1, wherein the compound of formula 1 is represented by one or more of the following formulae 1-1 to 1-6:

[ formula 1-1]

[ formulae 1-2]

[ formulae 1 to 3]

[ formulae 1 to 4]

[ formulae 1 to 5]

[ formulae 1 to 6]

In formulae 1-1 to 1-6,

R₂₁to R₂₆、R₃₁To R₃₆、R₄₁To R₄₆、R₅₁To R₅₆、R₆₁To R₆₆And R₇₁To R₇₆Each independently of the others, a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted alkyl group of 6 to 30An aryl group of ring carbon atoms or a substituted or unsubstituted heteroaryl group of 2 to 30 ring carbon atoms, and optionally bonded to an adjacent group to form a ring,

m21 to m26, m31 to m36, m41 to m46, m51 to m56, m61 to m66 and m71 to m76 are each, independently of one another, an integer of 1 to 4, and

Ar₁₁、Ar₁₂、Ar₂₁、Ar₂₂、Ar₃₁、Ar₃₂、Ar₄₁、Ar₄₂、Ar₅₁、Ar₅₂、Ar₆₁and Ar₆₂Each independently of the other, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

4. A polycyclic compound according to claim 1, wherein R₁To R₄And Ar is same as₁And Ar₂The same is true.

5. The polycyclic compound of claim 1, wherein the compound of formula 1 comprises at least one compound from compound group 1:

[ Compound group 1]

6. An organic electroluminescent device comprising:

a first electrode;

a second electrode disposed on the first electrode; and

at least one organic layer disposed between the first electrode and the second electrode;

wherein the at least one organic layer comprises a polycyclic compound according to any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, wherein the polycyclic compound has a highest occupied molecular orbital level of-5.50 eV to-5.00 eV.

8. The organic electroluminescent device according to claim 6, wherein the polycyclic compound has a lowest excited triplet level of 3.00 to 3.20 eV.

9. The organic electroluminescent device of claim 6, wherein the at least one organic layer comprises:

a hole transport region including the polycyclic compound and disposed on the first electrode;

an emission layer disposed on the hole transport region; and

an electron transport region disposed between the emission layer and the second electrode.

10. The organic electroluminescent device of claim 9, wherein the emissive layer is configured to emit thermally activated delayed fluorescence.

11. The organic electroluminescent device of claim 9, wherein the emissive layer is configured to emit blue light.

Technical Field

Exemplary embodiments of the invention relate generally to organic electroluminescent devices, and more particularly, to a polycyclic compound for organic electroluminescent devices.

Background

Development of organic electroluminescent devices as image display devices is actively being performed. In contrast to a liquid crystal display device, an organic electroluminescent device is a so-called self-luminous display device in which holes and electrons injected from a first electrode and a second electrode are recombined in an emission layer and emit light as a light emitting material of an organic compound included in the emission layer to realize display.

In applying an organic electroluminescent device to a display apparatus, it is required to improve efficiency and lifespan of the organic electroluminescent device, and materials for the organic electroluminescent device are being developed to stably meet these requirements.

The above information disclosed in this background section is only for background understanding of the inventive concept and, therefore, may contain information that does not constitute prior art.

Disclosure of Invention

The organic electroluminescent device and the polycyclic compound used therein constructed according to the principles and exemplary embodiments of the invention have high efficiency and long life.

Additional features of the inventive concept will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the inventive concept.

According to an aspect of the invention, an organic electroluminescent device includes:

a first electrode;

a second electrode disposed on the first electrode; and

at least one organic layer disposed between the first electrode and the second electrode;

wherein the at least one organic layer comprises a polycyclic compound having a core structure comprising an n, n '-bicarbazole moiety and at least one optionally substituted carbazolyl group external to the core structure, the substituted or unsubstituted carbazolyl group of the core structure being substituted at any one of carbon atoms at the n + -1 position of the n, n' -bicarbazole moiety and at any one of carbon atoms at the n '+ -1 position of the n, n' -bicarbazole moiety, respectively; and is

n and n 'are independently an integer of 1 to 4 (wherein n + -1 and n' + -1 are not 0).

The variables n and n' may be the same; and the substituted or unsubstituted carbazolyl group of the core structure is substituted at a carbon atom at the n +1 position of the n, n '-bicarbazole moiety and a carbon atom at the n' +1 position of the n, n '-bicarbazole moiety, respectively, or at a carbon atom at the n-1 position of the n, n' -bicarbazole moiety and a carbon atom at the n '-1 position of the n, n' -bicarbazole moiety, respectively.

The polycyclic compound may have a symmetrical structure with respect to the linking group of the n, n' -bicarbazole moiety; and the linking group may be a group that connects the two carbazolyl groups via a direct bond at the carbon at the n-position and the carbon at the n '-position of the n, n' -bicarbazole moiety.

The nitrogen at position 9 of the at least one optionally substituted carbazolyl group may be bonded to an n, n' -bicarbazole moiety.

The highest occupied molecular orbital level of the polycyclic compound can be about-5.50 eV to about-5.00 eV.

The lowest excited triplet level of the polycyclic compound may be about 3.00eV to about 3.20 eV.

The at least one organic layer may include: a hole transport region including a polycyclic compound, disposed on the first electrode; an emission layer disposed on the hole transport region; and an electron transport region disposed between the emission layer and the second electrode.

The emission layer may be configured to emit thermally activated delayed fluorescence.

The emission layer may be configured to emit blue light.

The polycyclic compound may be represented by formula 1 below:

[ formula 1]

In the formula 1, the first and second groups,

l may be a direct bond;

R₁to R₄May each independently be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally be bonded to an adjacent group to form a ring;

m1 to m4 may each be, independently of one another, an integer from 1 to 4;

Z₁to Z₈May each independently be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally be bonded to an adjacent group to form a ring; and is

Z₁And Z₂、Z₂And Z₃And Z₃And Z₄May be represented by the following formula 2-1, and Z₅And Z₆、Z₆And Z₇And Z₇And Z₈At least one pair of them may be represented by the following formula 2-2:

in the formulae 2-1 and 2-2,

R₁₁and R₁₂May each, independently of the others, be a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms, and optionally be bonded to an adjacent group to form a ring-forming carbon atomLooping;

m11 and m12 may each, independently of the other, be an integer from 1 to 4; and is

Ar₁And Ar₂May each, independently of the others, be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms, a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

Formula 1 may have a symmetrical structure with respect to L.

The compound of formula 1 may be represented by one or more compounds of the following formulae 1-1 to 1-6 as defined herein.

Variable R₁To R₄May be the same as Ar₁And Ar₂May be the same.

The polycyclic compound may include at least one compound from compound group 1 as defined herein.

The organic layer may include a functional group, and the n, n '-bicarbazole moiety may include an n, n' -bicarbazole derivative.

According to another aspect of the invention, an organic electroluminescent device includes: a first electrode; a second electrode disposed on the first electrode; and at least one organic layer disposed between the first electrode and the second electrode; wherein the organic layer includes the polycyclic compound represented by formula 1 defined above.

Formula 1 may have a symmetrical structure with respect to L.

The compound of formula 1 may be represented by one or more compounds of the following formulae 1-1 to 1-6 as defined herein.

Variable R₁To R₄May be the same as Ar₁And Ar₂May be the same.

According to still another aspect of the invention, the polycyclic compound is represented by formula 1 defined above.

Formula 1 may have a symmetrical structure with respect to L.

The compound of formula 1 may be represented by one or more compounds of the following formulae 1-1 to 1-6 as defined herein.

Variable R₁To R₄May be the same as Ar₁And Ar₂May be the same.

The polycyclic compound may include at least one compound from compound group 1 as defined herein.

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 invention as claimed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the inventive concept.

Fig. 1 is a cross-sectional view schematically illustrating an exemplary embodiment of an organic electroluminescent device constructed according to principles of the invention.

Fig. 2 is a cross-sectional view schematically illustrating another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention.

Fig. 3 is a cross-sectional view schematically illustrating yet another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention.

Fig. 4 is a cross-sectional view schematically illustrating yet another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention.

Detailed Description

In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various exemplary embodiments or implementations of the invention. As used herein, "examples" and "embodiments" are interchangeable words, which are non-limiting examples of apparatus or methods that employ one or more of the inventive concepts disclosed herein. It may be evident, however, that the various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the various exemplary embodiments. Moreover, the various exemplary embodiments may be different, but are not necessarily exclusive. For example, the particular shapes, configurations and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment without departing from the inventive concept.

Unless otherwise indicated, the exemplary embodiments shown are to be understood as providing exemplary features of varying detail in some ways in which the inventive concepts may be practiced. Thus, unless otherwise indicated, features, components, modules, layers, films, panels, regions, and/or aspects and the like (hereinafter, individually or collectively referred to as "elements") of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.

The use of cross-hatching and/or shading is often provided in the figures to clarify the boundaries between adjacent elements. As such, unless otherwise specified, the presence or absence of cross-hatching or shading does not express or indicate any preference or requirement for a particular material, material property, dimension, proportion, commonality between the illustrated elements, and/or any other characteristic, attribute, property, etc. Further, in the drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. While example embodiments may be practiced differently, the specific process sequence may be performed in a different order than that described. For example, two processes described consecutively may be performed substantially simultaneously or in reverse order to that described. In addition, like reference numerals denote like elements.

When an element or layer is referred to as being "on," "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. However, when an element or layer is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. To this end, the term "connected" may refer to physical, electrical, and/or fluid connections, with or without intervening elements. Further, the D1 axis, the D2 axis, and the D3 axis are not limited to three axes (such as x-axis, y-axis, and z-axis) of a rectangular coordinate system, and may be explained in a broader sense. For example, the D1, D2, and D3 axes may be perpendicular to each other, or may represent different directions that are not perpendicular to each other. For the purposes of this disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" can be understood as any combination of two (species/ones) or more of X only, Y only, Z only, or X, Y and Z, such as, for example, XYZ, XYY, YZ, and ZZ. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.

Spatially relative terms such as "below … …," "below … …," "below … …," "below," "above … …," "above," "… …," "higher," "side" (e.g., as in "sidewall"), etc., may be used herein for descriptive purposes to describe one element's (e.g., layer, film, region, plate, etc.) relationship to another (other) element as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below … …" can encompass both an orientation of above and below. Further, the devices may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, when the terms "comprises" and/or "comprising" and variations thereof are used in this specification, the presence of stated features, integers, steps, operations, elements, components and/or groups thereof are stated but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. It is also noted that, as used herein, the terms "substantially," "about" and other similar terms are used as terms of approximation and not as terms of degree, and as such, are used to interpret the inherent variation of measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference to cross-sectional and/or exploded illustrations that are schematic illustrations of idealized exemplary embodiments and/or intermediate structures. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments disclosed herein should not necessarily be construed as limited to the shapes of regions specifically illustrated, but are to include deviations in shapes that result, for example, from manufacturing. In this manner, the regions illustrated in the figures may be schematic in nature and the shapes of the regions may not reflect the actual shape of a region of a device and, as such, are not necessarily intended to be limiting.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the term "substituted or unsubstituted" corresponds to being unsubstituted or substituted with at least one substituent selected from the group consisting of a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group (or referred to as "oxy group"), a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphinoxide group, a phosphinyl sulfide group, an alkyl group, an alkenyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group. In addition, each of the substituents may be substituted or unsubstituted. For example, biphenyl can be interpreted as an aryl group or a phenyl group substituted with a phenyl group.

As used herein, the term "form a ring via bonding to an adjacent group" may mean to form a substituted or unsubstituted hydrocarbon ring or a substituted or unsubstituted heterocyclic ring via bonding to an adjacent group. The hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The heterocyclic ring includes aliphatic heterocyclic rings and aromatic heterocyclic rings. The hydrocarbon ring and the heterocyclic ring may be monocyclic or polycyclic. In addition, a ring formed by being combined with each other may be combined with another ring to form a screw structure.

As used herein, the term "adjacent group" may denote a substituent substituted for an atom directly bonded to an atom substituted with the corresponding substituent, another substituent substituted for an atom substituted with the corresponding substituent, or a substituent located sterically closest to the corresponding substituent. For example, in 1, 2-dimethylbenzene, two methyl groups can be interpreted as "vicinal groups" to each other, and in 1, 1-diethylcyclopentane, two ethyl groups can be interpreted as "vicinal groups" to each other.

As used herein, a halogen atom may be a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. Furthermore, the terms "hydrogen", "deuterium", "fluorine", "chlorine", "bromine" and "iodine" refer to their respective atoms and the corresponding radicals.

As used herein, an alkyl group may be linear, branched, or cyclic. The number of carbons in the alkyl group may be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Examples of the alkyl group may include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, 2-ethylbutyl, 3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, cyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, n-heptyl, 1-methylheptyl, 2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 2-ethylpentyl, 2-ethylbutyl, 3-dimethylbutyl, n-pentyl, 3-methylpentyl, 2-methylhexyl, 3, 7-dimethyloctyl, cyclooctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl, n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, N-heneicosyl, n-docosyl, n-tricosyl, n-tetracosyl, n-pentacosyl, n-hexacosyl, n-heptacosyl, n-octacosyl, n-nonacosyl, n-triacontyl, etc., without limitation.

As used herein, hydrocarbon ring group means an optional functional group or substituent derived from an aliphatic hydrocarbon ring. The hydrocarbon ring group may be a saturated hydrocarbon ring group of 5 to 20 ring-forming carbon atoms.

As used herein, aryl represents an optional functional group or substituent derived from an aromatic hydrocarbon ring. The aryl group may be a monocyclic aryl group or a polycyclic aryl group. The number of carbons in the aryl group for forming a ring may be 6 to 30, 6 to 20, or 6 to 15. Examples of the aryl group may include phenyl, naphthyl, fluorenyl, anthracenyl, phenanthryl, biphenyl, terphenyl, quaterphenyl, pentabiphenyl, hexabiphenyl, benzo [9,10 ]]Phenanthryl, pyrenyl, benzofluoranthenyl, phenanthrenyl, pyrenyl, phenanthrenyl, pyrenyl,and the like without limitation.

As used herein, heterocyclyl groups may include B, O, N, P, Si and one or more of S as heteroatoms. If a heterocyclyl includes two or more heteroatoms, the two or more heteroatoms may be the same or different. The heterocyclic group may be a monocyclic heterocyclic group or a polycyclic heterocyclic group, and includes, for example, a heteroaryl group. The carbon number of the ring for forming the heteroaryl group may be 2 to 30, 2 to 20, or 2 to 10.

As used herein, the carbon number of the ring used to form the heteroaryl group may be 2 to 30, 2 to 20, or 2 to 10. Examples of the heteroaryl group may include thienyl, furyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, N-arylcarbazolyl, N-heteroarylcarbazolyl, N-alkylcarbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, benzocarbazolyl, benzothienyl, dibenzothienyl, thienothienyl, benzofuryl, phenanthrolinyl, isoxazolyl, thiadiazolyl, phenothiazinyl, dibenzothienyl, dibenzofuryl, and the like, without limitation.

As used herein, the carbon number of the amine group (or amino group) is not particularly limited, but may be 1 to 30. The amine group may include an alkylamino group, an arylamine group, or a heteroarylamine group. Examples of the amine group include a methylamino group, a dimethylamino group, a phenylamino group, a diphenylamino group, a naphthylamino group, a 9-methyl-anthracenylamino group, and the like, without limitation.

As used herein, an alkenyl group can be straight or branched. The number of carbons is not particularly limited, and may be 2 to 30, 2 to 20, or 2 to 10. Examples of the alkenyl group may include a vinyl group, a 1-butenyl group, a 1-pentenyl group, a 1, 3-butadienylaryl group, a styryl group, a styrylvinyl group, and the like, without limitation.

As used herein, the term "moiety" means a portion of a compound.

In the specification, "" denotes a connection position.

As used herein, a direct bond may represent a single bond.

Fig. 1 is a cross-sectional view schematically illustrating an exemplary embodiment of an organic electroluminescent device constructed according to principles of the invention. Fig. 2 is a cross-sectional view schematically illustrating another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention. Fig. 3 is a cross-sectional view schematically illustrating yet another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention. Fig. 4 is a cross-sectional view schematically illustrating yet another exemplary embodiment of an organic electroluminescent device constructed according to principles of the present invention.

Referring to fig. 1, an organic electroluminescent device 10 according to an exemplary embodiment may include a first electrode EL1, at least one organic layer, and a second electrode EL2, which are sequentially stacked. The organic layer may be an organic layer including an organic material, but exemplary embodiments are not limited thereto. For example, the organic layer can include a metal-containing compound, such as at least one of a lanthanide metal, a metal halide, and a metal oxide. In addition, the organic layer may include an inorganic material such as at least one of quantum dots and quantum rods.

The at least one organic layer may include at least one of a hole transport region HTR, an emission layer EML, and an electron transport region ETR as discussed in further detail below.

Referring to fig. 1 to 4, in an organic electroluminescent device 10 according to an exemplary embodiment, a first electrode EL1 and a second electrode EL2 are oppositely disposed, and an emission layer EML may be disposed between the first electrode EL1 and the second electrode EL 2.

In addition, the organic electroluminescent device 10 includes a plurality of organic layers between the first electrode EL1 and the second electrode EL2 in addition to the emission layer EML. The plurality of organic layers may include a hole transport region HTR and an electron transport region ETR. That is, the organic electroluminescent device 10 may include the first electrode EL1, the hole transport region HTR, the emission layer EML, the electron transport region ETR, and the second electrode EL2, which are sequentially stacked. In addition, the organic electroluminescent device 10 may include a cap layer CPL disposed on the second electrode EL2 as depicted in fig. 4.

The organic electroluminescent device 10 may include a polycyclic compound described in further detail below in a hole transport region HTR disposed between the first electrode EL1 and the second electrode EL 2. However, exemplary embodiments are not limited thereto, and the organic electroluminescent device 10 of some exemplary embodiments may include a polycyclic compound, which will be described in further detail below, in the emission layer EML as an organic layer disposed between the first electrode EL1 and the second electrode EL2 or in the electron transport region ETR as an organic layer disposed between the first electrode EL1 and the second electrode EL2, or in the cap layer CPL disposed on the second electrode EL2 in addition to the hole transport region HTR.

Fig. 2 shows a cross-sectional view of the organic electroluminescent device 10, when compared to fig. 1, in which the hole transport region HTR includes a hole injection layer HIL and a hole transport layer HTL, and the electron transport region ETR includes an electron injection layer EIL and an electron transport layer ETL. In addition, fig. 3 shows a cross-sectional view of an exemplary embodiment of the organic electroluminescent device 10, when compared to fig. 1, in which the hole transport region HTR includes a hole injection layer HIL, a hole transport layer HTL, and an electron blocking layer EBL, and the electron transport region ETR includes an electron injection layer EIL, an electron transport layer ETL, and a hole blocking layer HBL. Fig. 4 shows a cross-sectional view of an exemplary embodiment of the organic electroluminescent device 10 comprising a capping layer CPL provided on the second electrode EL2, when compared to fig. 1.

The at least one organic layer may include a polycyclic compound. A polycyclic compound according to an exemplary embodiment may include a core structure and a substituent substituted at the core structure. The core structure may include an n, n' -bicarbazole moiety. In at least some exemplary embodiments, the n, n '-bicarbazole moiety may be in the form of an n, n' -bicarbazole derivative.

The substituent substituted at the core structure may be a substituted or unsubstituted carbazolyl group. The substituted or unsubstituted carbazolyl group may be substituted at any one of carbon atoms at the n + -1 position and any one of carbon atoms at the n '+ -1 position of the n, n' -bicarbazole moiety, respectively. The nitrogen at position 9 of the substituted or unsubstituted carbazolyl group may be bound to and substituted at the n, n' -bicarbazole moiety.

The variables n and n ' may be integers from 1 to 4, n + -1 and n ' + -1 may not be 0, and n ' may be the same. For example, the core structure may be a 1,1 '-bicarbazole moiety, a 2,2' -bicarbazole moiety, a 3,3 '-bicarbazole moiety, or a 4,4' -bicarbazole moiety.

The substituted or unsubstituted carbazolyl group substituted at the core structure may be substituted at the carbon at the n +1 position and the carbon at the n '+1 position of the n, n' -bicarbazole moiety, respectively, or may be substituted at the carbon at the n-1 position and the carbon at the n '-1 position of the n, n' -bicarbazole moiety, respectively.

The polycyclic compound may have a symmetrical or asymmetrical structure with respect to the linking group of the n, n' -bicarbazole moiety. The linking group represents a group that links two carbazolyl groups via a direct bond at a carbon at the n-position and a carbon at the n '-position of the n, n' -bicarbazole moiety. If the polycyclic compound has a symmetrical structure, it may have a line-symmetrical or point-symmetrical structure with respect to the linking group of the n, n' -bicarbazole moiety.

The polycyclic compound may be represented by formula 1 below:

[ formula 1]

In formula 1, formula a may be defined as a core structure.

[ formula A ]

In formula a, "-" indicates a bonding position to a substituted or unsubstituted carbazole substituent.

In formula 1, L may be a direct bond. R₁To R₄May each independently be a hydrogen atom, a deuterium atom, a halogen atom, an amino group, an alkyl group, an aryl group or a hetero groupAryl, and optionally combined with an adjacent group to form a ring. The amino group may be a substituted or unsubstituted amino group. The alkyl group may be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms. The aryl group may be a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms. The heteroaryl group may be a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

For example, R₁To R₄May each independently be a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, or a substituted or unsubstituted phenyl group. All R₁To R₄May be the same.

m1 to m4 may each independently be an integer of 1 to 4. m1 to m4 may be the same or different. For example, all m1 to m4 may be the same. m1 and m4 may be the same. m2 and m3 may be the same.

If m1 is an integer of 2 or more, then multiple R' s₁The groups may be the same or different. The same explanation regarding m1 can be applied to m2 to m 4.

Z₁To Z₈May each independently be a hydrogen atom, a deuterium atom, a halogen atom, an amino group, an alkyl group, an aryl group, or a heteroaryl group, and may optionally be bonded to an adjacent group to form a ring. The amino group may be a substituted or unsubstituted amino group. The alkyl group may be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms. The aryl group may be a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms. The heteroaryl group may be a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

Z₁And Z₂、Z₂And Z₃And Z₃And Z₄Is represented by the following formula 2-1, and Z₅And Z₆、Z₆And Z₇And Z₇And Z₈At least one pair of them may be represented by the following formula 2-2:

in the formulae 2-1 and 2-2, R₁₁And R₁₂Can all be independentIs a hydrogen atom, a deuterium atom, a halogen atom, an amino group, an alkyl group, an aryl group or a heteroaryl group, and optionally combines with an adjacent group to form a ring. The amino group may be a substituted or unsubstituted amino group. The alkyl group may be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms. The aryl group may be a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms. The heteroaryl group may be a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

The variables m11 and m12 may each independently be an integer from 1 to 4, and m11 and m12 may be the same or different. If m11 is an integer of 2 or more, then multiple R' s₁₁The groups may be the same or different. If m12 is an integer of 2 or more, then multiple R' s₁₂The groups may be the same or different.

Ar₁And Ar₂May each independently be an alkyl, aryl or heteroaryl group. The alkyl group may be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms. The aryl group may be a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms. The heteroaryl group may be a substituted or unsubstituted heteroaryl group of 2 to 30 ring-forming carbon atoms.

For example, Ar₁And Ar₂May each independently be a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted dibenzoheterocyclyl group. The dibenzoheterocyclyl group may include, for example, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted carbazolyl group. Ar (Ar)₁And Ar₂May be the same.

In formula 2-1 and formula 2-2, "-" indicates the position of the linkage to formula a.

Formula 1 may be represented by formula 1-a below:

[ formula 1-A ]

Formula 1-A is wherein R in formula 1₁To R₄The substitution position of (a) is defined. In formula 1-A, L, R₁To R₄M1 to m4 and Z₁To Z₈May be defined in the same manner as in formula 1.

Formula 2-1 and formula 2-2 may each be independently represented by the following formulae 3-1 to 3-3:

in formula 3-1, p may be an integer of 0 to 5. In formula 3-3, X may be O, NR_1-1Or S. R_1-1It may be a substituted or unsubstituted alkyl group of 1 to 20 carbon atoms or a substituted or unsubstituted aryl group of 6 to 30 ring-forming carbon atoms. R_1-1It may be, for example, phenyl.

Formula 1 may have a symmetrical structure or an asymmetrical structure with respect to L. Equation 1 may have a line-symmetric or point-symmetric structure with respect to L.

Formula 1 may be represented by the following formulae 1-1 to 1-6:

[ formula 1-1]

[ formulae 1-2]

[ formulae 1 to 3]

[ formulae 1 to 4]

[ formulae 1 to 5]

[ formulae 1 to 6]

In the formulae 1-1 to 1-6, R₂₁To R₂₆、R₃₁To R₃₆、R₄₁To R₄₆、R₅₁To R₅₆、R₆₁To R₆₆And R₇₁To R₇₆May be represented by the formula 1₁To R₄In the same manner as defined above.

m21 to m26, m31 to m36, m41 to m46, m51 to m56, m61 to m66, and m71 to m76 may be defined in the same manner as m1 to m4 defined in formula 1.

Ar₁₁And Ar₁₂、Ar₂₁And Ar₂₂、Ar₃₁And Ar₃₂、Ar₄₁And Ar₄₂、Ar₅₁And Ar₅₂And Ar₆₁And Ar₆₂May be substituted with Ar defined in formula 1₁And Ar₂In the same manner as defined above.

Formula 1 may include at least one of the compounds represented in the following compound group 1:

[ Compound group 1]

In compound group 1, Me is methyl, Et is ethyl and Ph is phenyl.

As explained in further detail below, the hole transport region HTR may include a polycyclic compound.

The first electrode EL1 has conductivity. The first electrode EL1 may be formed using a metal alloy or a conductive compound. The first electrode EL1 may be an anode. In addition, the first electrode EL1 may be a pixel electrode. The first electrode EL1 may be a transmissive electrode, a transflective electrode, or a reflective electrode. If the first electrode EL1 is a transmissive electrode, the first electrode EL1 may include a transparent metal oxide, for example, Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), zinc oxide (ZnO), Indium Tin Zinc Oxide (ITZO), and the like. If the first electrode EL1 is a transflective or reflective electrode, the first electrode EL1 can include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Al, Mo, Ti, composites thereof, or mixtures thereof (e.g., a mixture of Ag and Mg). Alternatively, the first electrode EL1 may have a structure including a plurality of layers including a reflective layer or a transflective layer formed using the above-described materials and a transmissive conductive layer formed using ITO, IZO, ZnO, ITZO, or the like. For example, the first electrode EL1 may include a triple layer structure of ITO/Ag/ITO. However, the exemplary embodiments are not limited thereto. The thickness of the first electrode EL1 may be aboutTo aboutFor example, aboutTo about

The hole transport region HTR is disposed on the first electrode EL 1. The hole transport region HTR may include the above-described polycyclic compound. The hole transport region HTR may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multilayer structure including a plurality of layers formed using a plurality of different materials. The hole transport region HTR may be a single layer formed using a polycyclic compound, a single layer formed using another compound other than the polycyclic compound, or a multilayer structure including only the polycyclic compound or a mixture including the polycyclic compound in at least one layer.

The hole transport region HTR may include at least one of a hole injection layer HIL, a hole transport layer HTL, a hole buffer layer, and an electron blocking layer EBL. At least one of the hole injection layer HIL, the hole transport layer HTL, the hole buffer layer, and the electron blocking layer EBL may include a polycyclic compound.

Since the polycyclic compound of some exemplary embodiments includes at least four carbazole groups, the hole transporting property is excellent. In particular, since some exemplary embodiments of the polycyclic compounds are highly symmetric about the linking group, and the carbazole substituent is substituted at an ortho position with respect to the linking group of the core structure, better hole transport properties may be exhibited. Accordingly, the organic electroluminescent device 10 of some exemplary embodiments includes a polycyclic compound in the hole transport region HTR and may achieve high efficiency and long life.

The hole transport region HTR may have a single-layer structure of the hole injection layer HIL or the hole transport layer HTL or a single-layer structure formed using a hole injection material and a hole transport material. In addition, the hole transport region HTL may have a single-layer structure formed using a plurality of different materials, or a structure of a hole injection layer HIL/hole transport layer HTL, a hole injection layer HIL/hole transport layer HTL/hole buffer layer, a hole injection layer HIL/hole buffer layer, a hole transport layer HTL/hole buffer layer, or a hole injection layer HIL/hole transport layer HTL/electron blocking layer EBL stacked from the first electrode EL1, without limitation.

The hole transport region HTR may be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgett (LB) method, an inkjet printing method, a laser printing method, and a Laser Induced Thermal Imaging (LITI) method.

The hole injection layer HIL may include, for example, phthalocyanine compounds such as copper phthalocyanine, N '-diphenyl-N, N' -bis [ 4-di (m-tolyl) -amino-phenyl ] -biphenyl-4, 4 '-diamine (DNTPD), 4',4"- [ tris (3-methylphenyl) phenylamino ] triphenylamine (m-MTDATA), 4',4 ″ -tris (N, N-diphenylamino) triphenylamine (TDATA), 4',4 ″ -tris { N- (2-naphthyl) -N-phenylamino } -triphenylamine (2-TNATA), poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), Polyaniline/camphorsulfonic acid (PANI/CSA), polyaniline/poly (4-styrenesulfonate) (PANI/PSS), N ' -di (naphthalene-1-yl) -N, N ' -diphenyl-benzidine (NPD or NPB), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4 ' -methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, and dipyrazino [2,3-f:2',3' -h ] quinoxaline-2, 3,6,7,10, 11-hexanenitrile (HAT-CN).

The hole transport layer HTL may include, for example, carbazole compounds such as N-phenylcarbazole and polyvinylcarbazole compounds, fluorene-based compounds, N '-bis (3-methylphenyl) -N, N' -diphenyl- [1,1 '-biphenyl ] -4,4' -diamine (TPD), triphenylamine-based compounds such as 4,4',4 ″ -tris (carbazol-9-yl) triphenylamine (TCTA), N' -bis (naphthalene-1-yl) -N, N '-diphenyl-benzidine (NPB), 4' -cyclohexylidenebis [ N, N-bis (4-methylphenyl) aniline ] (TAPC), 4 '-bis [ N, N' - (3-tolyl) amino ] -3,3' -dimethylbiphenyl (HMTPD), 1, 3-bis (N-carbazolyl) benzene (mCP), 9- (4-tert-butylphenyl) -3, 6-bis (triphenylsilyl) -9H-carbazole (CzSi), and the like.

The thickness of the hole transport region HTR may be aboutTo aboutFor example, aboutTo aboutThe thickness of the hole injection layer HIL may be, for example, aboutTo aboutThe thickness of the hole transport layer HTL may be aboutTo aboutFor example, the electron blocking layer EBL may be about thickTo aboutIf the thicknesses of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer EBL satisfy the above-described ranges, satisfactory hole transport properties can be achieved without significantly increasing the driving voltage.

In addition to the above materials, the hole transport region HTR may further include a charge generation material to increase conductivity. The charge generation material may be uniformly or non-uniformly dispersed in the hole transport region HTR. The charge generating material may be, for example, a p-dopant. The p-dopant may be one of a quinone compound, a metal oxide, and a cyano group-containing compound without limitation. For example, non-limiting examples of the p-dopant may include quinone compounds such as Tetracyanoquinodimethane (TCNQ) and 2,3,5, 6-tetrafluoro-7, 7,8, 8-tetracyanoquinodimethane (F4-TCNQ), metal oxides such as tungsten oxide and molybdenum oxide, and the like, without limitation.

As described above, the hole transport region HTR may include at least one of the hole buffer layer and the electron blocking layer EBL in addition to the hole injection layer HIL and the hole transport layer HTL. The hole buffer layer may compensate an optical resonance distance according to a wavelength of light emitted from the emission layer EML to improve light emitting efficiency. A material that can be included in the hole transport region HTR can be used as a material included in the hole buffer layer. The electron blocking layer EBL is a layer that functions to prevent electrons from being injected from the electron transport region ETR to the hole transport region HTR.

The emission layer EML is disposed on the hole transport region HTR. The thickness of the emissive layer EML may be, for example, aboutTo aboutOr aboutTo aboutThe emission layer EML may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layer structure having a plurality of layers formed using a plurality of different materials.

In the organic electroluminescent device 10 of some exemplary embodiments, the emission layer EML may include one or more of an anthracene compound, a pyrene compound, a fluoranthene compound, a perylene compound,compounds, dihydrobenzanthracene compounds or benzo [9,10 ]]Phenanthrene compounds. Specifically, the emission layer EML may include one or more anthracene compounds or pyrene compounds.

In the organic electroluminescent device 10 of at least some example embodiments, as shown in fig. 1 to 4, the emission layer EML may include a host and a dopant.

The emission layer EML may include a commonly used material known in the art as a host material. For example, the emissive layer EML may include bis [2- (diphenylphosphino) phenyl [ ]]Ether oxide (DPEPO), 4' -bis (carbazol-9-yl) biphenyl (CBP), 1, 3-bis (carbazol-9-yl) benzene (mCP), 2, 8-bis (diphenylphosphoryl) dibenzo [ b, d]Furan (PPF), 4' -tris (carbazol-9-yl) triphenylamine and 1,3, 5-tris (1-phenyl-1H-benzo [ d ]]At least one of imidazol-2-yl) benzene (TPBi) as a host material. However, the exemplary embodiments are not limited thereto. For example, tris (8-hydroxyquinoline) aluminum (Alq)₃) 4,4 '-bis (N-carbazolyl) -1,1' -biphenyl (CBP), poly (N-vinylcarbazole) (PVK), 9, 10-bis (naphthalen-2-yl) Anthracene (ADN), 3-tert-butyl-9, 10-bis (naphthalen-2-yl) anthracene (TBADN), Distyrylarylide (DSA), 4 '-bis (9-carbazolyl) -2,2' -dimethyl-biphenyl (CDBP), 2-methyl-9, 10-bis (naphthalen-2-yl) anthracene (MADN), bis [2- (diphenylphosphino) phenylphenyl]Ether oxide (DPEPO), hexaphenylcyclotriphosphazene (CP1), 1, 4-bis (triphenylsilyl) benzene (UGH2), hexaphenylcyclotrisiloxane (DPSiO)₃) Octaphenylcyclotetrasiloxane (DPSiO)₄) 2, 8-bis (diphenylphosphoryl) dibenzofuran (PPF), 9- (4-tert-butylphenyl) -3, 6-bis (triphenylsilyl) -9H-carbazole, and the like can be used as the host material.

In exemplary embodiments, the emission layer EML may include styrene compounds (e.g., 1, 4-bis [2- (3-N-ethylcarbazolyl) vinyl ] benzene (BCzVB), 4- (di-p-tolylamino) -4'- [ (di-p-tolylamino) styryl ] stilbene (DPAVB) and N- (4- ((E) -2- (6- ((E) -4- (diphenylamino) styryl) naphthalen-2-yl) vinyl) phenyl) -N-phenylaniline (N-BDAVBi)), perylene and related compounds (e.g., 2,5,8, 11-tetra-t-butylperylene (TBP)), pyrene and related compounds (e.g., 1,1' -dipepyrene, tbb), as known dopant materials, 1, 4-bipyrenylbenzene, 1, 4-bis (N, N-diphenylamino) pyrene) and the like.

The emissive layer EML may emit fluorescence or phosphorescence. The emissive layer EML may emit delayed fluorescence. The emission layer EML may emit first, second, and third color lights. The first color light may be blue light, the second color light may be green light, and the third color light may be red light. The blue light may be blue light having a central wavelength of about 410nm to about 500 nm. The green light may be green light having a center wavelength of about 500nm to about 570 nm. The red light may be red light having a center wavelength of about 570nm to about 700 nm. Exemplary embodiments of the invention are not limited thereto, but if the emission layer EML emits red or green light, it may emit phosphorescence, and if the emission layer EML emits blue light, it may emit fluorescence or delay fluorescence.

If the emission layer EML emits delayed fluorescence, the emission layer EML may include a material for thermally activating the delayed fluorescence. A material for thermally activating delayed fluorescence may be used as a host or a dopant of the emission layer EML. For example, the material for thermally activating delayed fluorescence may be a donor-acceptor type material for thermally activating delayed fluorescence (such as 10-phenyl-10H, 10' H-spiro [ acridine-9, 9' -anthracen ] -10' -one) or a boron-containing type material for thermally activating delayed fluorescence (such as 5, 9-diphenyl-5H, 9H- [1,4] benzazepino [2,3,4-k1] phenanthreneazaborone).

The polycyclic compound may have a relatively high lowest excited triplet energy level of about 3.00eV to about 3.20 eV. This energy level is the lowest excited triplet energy level, which can be suitably applied to the hole transport layer HTL of the organic electroluminescent device emitting thermally activated delayed fluorescence. Therefore, the polycyclic compound can be applied to a hole transport region of an organic electroluminescent device emitting blue thermally activated delayed fluorescence to obtain excellent effects.

The polycyclic compound may have a relatively deep highest occupied molecular orbital level of about-5.50 eV to about-5.00 eV. Therefore, if the organic electroluminescent device has a stacked structure of first hole transport layer/second hole transport layer/emission layer EML, a polycyclic compound may be included in the second hole transport layer and may function to eliminate a hole transport barrier from the first hole transport layer to the emission layer EML. Accordingly, holes can be more rapidly transported from the hole transport region HTR to the emission layer EML.

Therefore, if the emission layer EML emits thermally activated delayed fluorescence and the hole transport region HTR includes a polycyclic compound, high efficiency and long life of the organic electroluminescent device 10 can be achieved.

As described above, the emission layer EML is explained as including an organic light emitting material, but exemplary embodiments of the invention are not limited thereto. In an exemplary embodiment, the emission layer EML may include an inorganic luminescent material. For example, the emission layer EML may include inorganic luminescent materials such as quantum dots and quantum rods.

In the organic electroluminescent device 10 shown in fig. 1 to 4, the electron transport region ETR is disposed on the emission layer EML. The electron transport region ETR may include at least one of a hole blocking layer HBL, an electron transport layer ETL, and an electron injection layer EIL. However, the exemplary embodiments are not limited thereto.

The electron transport region ETR may have a single layer formed using a single material, a single layer formed using a plurality of different materials, or a multi-layer structure having a plurality of layers formed using a plurality of different materials.

For example, the electron transport region ETR may have a single-layer structure of the electron injection layer EIL or the electron transport layer ETL or a single-layer structure formed using an electron injection material and an electron transport material. In addition, the electron transport region ETR may have a single layer structure formed using a plurality of different materials or a structure of the electron transport layer ETL/the electron injection layer EIL or the hole blocking layer HBL/the electron transport layer ETL/the electron injection layer EIL stacked from the emission layer EML without limitation. The thickness of the electron transport region ETR may be, for example, aboutTo about

The electron transport region ETR may be formed using various methods such as a vacuum deposition method, a spin coating method, a casting method, a langmuir-blodgett (LB) method, an inkjet printing method, a laser printing method, and a Laser Induced Thermal Imaging (LITI) method.

If the electron transport region ETR includes the electron transport layer ETL, the electron transport region ETR may include an anthracene compound. Exemplary embodiments are not limited thereto, but the electron transport region ETR may include, for example, tris (8-hydroxyquinoline) aluminum (Alq)₃) 1,3, 5-tris [ (3-pyridyl) -phen-3-yl]Benzene, 2,4, 6-tris (3' - (pyridin-3-yl) biphenyl-3-yl) -1,3, 5-triazine, 2- (4- (N-phenylbenzimidazol-1-yl) phenyl) -9, 10-dinaphthylanthracene, 1,3, 5-tris (1-phenyl-1H-benzo [ d ] b]Imidazol-2-yl) benzene (TPBi), 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP), 4, 7-diphenyl-1, 10-phenanthroline (Bphen), 3- (4-biphenyl) -4-phenyl-5-tert-butylphenyl-1, 2, 4-Triazole (TAZ), 4- (naphthalen-1-yl) -3, 5-diphenyl-4H-1, 2, 4-triazole (NTAZ), 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole (tBu-PBD), bis (2-methyl-8-hydroxy-p-henyl)quinoline-N1, O8) - (1,1' -biphenyl-4-hydroxy) aluminum (BALq), bis (benzoquinoline-10-hydroxy) beryllium (Bebq)₂) 9, 10-bis (naphthalen-2-yl) Anthracene (ADN), 1, 3-bis [3, 5-bis (pyridin-3-yl) phenyl]Benzene (BmPyPhB) or mixtures thereof. The thickness of the electron transport layer ETL may be aboutTo aboutAnd may be, for example, aboutTo aboutIf the thickness of the electron transport layer ETL satisfies the above range, a satisfactory electron transport property can be obtained without significantly increasing the driving voltage.

If the electron transport region ETR includes the electron injection layer EIL, the electron transport region ETR may use a metal halide such as LiF, NaCl, CsF, RbCl, and RbI, a lanthanide metal such as Yb, a lanthanide metal such as Li₂Metal oxides of O and BaO or lithium hydroxyquinoline (LiQ). However, the exemplary embodiments are not limited thereto. The electron injection layer EIL may also be formed using a mixture material of an electron transport material and an insulating organic metal salt. The organometallic salt may be a material having an energy bandgap of about 4eV or more. In particular, the organometallic salt may include, for example, one or more metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, or metal stearates. The thickness of the electron injection layer EIL may be aboutTo aboutAnd is aboutTo aboutIf the thickness of the electron injection layer EIL satisfies the above range, satisfactory electron injection properties can be obtained without causing a significant increase in driving voltage.

The electron transport region ETR may comprise a hole blocking layer HBL as described above. The hole blocking layer HBL may include, for example, at least one of 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) and 4, 7-diphenyl-1, 10-phenanthroline (Bphen). However, the exemplary embodiments are not limited thereto.

The second electrode EL2 is disposed on the electron transport region ETR. The second electrode EL2 may be a common electrode or a cathode. The second electrode EL2 may be a transmissive electrode, a transflective electrode, or a reflective electrode. If the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed using a transparent metal oxide (e.g., ITO, IZO, ZnO, ITZO, etc.).

If the second electrode EL2 is a transflective or reflective electrode, the second electrode EL2 can include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Al, Mo, Ti, composites thereof, or mixtures thereof (e.g., a mixture of Ag and Mg). Alternatively, the second electrode EL2 may have a multilayer structure including a reflective layer or a transflective layer formed using the above-described materials and a transparent conductive layer formed using ITO, IZO, ZnO, ITZO, or the like.

The second electrode EL2 may be connected to an auxiliary electrode. If the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

In some exemplary embodiments, a cap layer CPL may be further disposed on the second electrode EL2 of the organic electroluminescent device 10. The cap layer CPL may comprise, for example, 2' -dimethyl-N, N ' -di [ (1-naphthyl) -N, N ' -diphenyl]-1,1 '-biphenyl-4, 4' -diamine (. alpha. -NPD), NPB, TPD, m-MTDATA, Alq₃Copper (II) phthalocyanine (CuPc), N4, N4, N4', N4' -tetrakis (biphenyl-4-yl) biphenyl-4, 4 '-diamine (TPD15), 4',4 ″ -tris (carbazol-9-yl) triphenylamine (TCTA), and the like.

The above-described compounds may be included in an organic layer other than the hole transport region HTR as a material for the organic electroluminescent device 10. The organic electroluminescent device 10 may include the above-described compound in at least one organic layer disposed between the first electrode EL1 and the second electrode EL2 or in the cap layer CPL disposed on the second electrode EL 2.

In the organic electroluminescent device 10, according to the application of voltages to the first electrode EL1 and the second electrode EL2, respectively, holes injected from the first electrode EL1 move to the emission layer EML through the hole transport region HTR, and electrons injected from the second electrode EL2 move to the emission layer EML through the electron transport region ETR. The electrons and holes are recombined in the emission layer EML to generate excitons, and light is emitted by transition of the excitons from an excited state to a ground state.

Hereinafter, the polycyclic compound and the organic electroluminescent device according to the exemplary embodiments will be specifically described with reference to the exemplary embodiments and the comparative examples. The following exemplary embodiments are merely illustrations to help understanding of the inventive concept, and the inventive concept is not limited thereto.

1. Synthesis examples

For example, the polycyclic compound can be synthesized as follows. However, exemplary embodiments of the synthetic method of preparing the polycyclic compound are not limited thereto.

1-1 Synthesis of Compound 1

For example, polycyclic compound 1 can be synthesized by reaction 1 below:

[ reaction 1]

Synthesis of intermediate C

Reaction A (25.0g), bis (pinacol) diboron (29.2g) and [1,1' -bis (diphenylphosphino) ferrocene were reacted under argon atmosphere]Palladium (II) dichloride dichloromethane adduct (Pd (dppf) Cl₂7.85g) and potassium acetate (KOAc, 28.1g) were placed in a 1,000mL three-necked flask and dissolved in dioxane (300mL), followed by heating and stirring at about 90 ℃ for about 6 hours. Adding water to the reaction product and reacting the resulting mixture with CH₂Cl₂And (4) extracting. The organic layer was collected and MgSO anhydrous₄Dried and the solvent was removed by distillation under reduced pressure. The thus-obtained crude product was separated by silica gel column chromatography to obtain 19.2g (yield 65%) of intermediate C. The molecular weight of intermediate C was 308 as measured by fast atom bombardment mass spectrometry (FAB-MS).

Synthesis of intermediate D

20.5g (yield 72%) of intermediate D was obtained from reactant B (25.0g) by carrying out the same method as the synthesis method of intermediate C described above. The molecular weight of intermediate D as measured by FAB-MS was 384.

Synthesis of intermediate E

Intermediate C (15.0g), reactant A (12.7g), tetrakis (triphenylphosphine) palladium (0) (Pd (PPh) under argon atmosphere₃)₄5.62g) and tripotassium phosphate (K)₃PO₄20.7g) was placed in a 1,000mL three-necked flask and dissolved in a mixed solvent of toluene, water and ethanol (10:2:1, 200mL), followed by heating and stirring at about 80 ℃ for about 12 hours. Adding water to the reaction product and reacting the resulting mixture with CH₂Cl₂And (4) extracting. The organic layer was collected and MgSO anhydrous₄Dried and the solvent was removed by distillation under reduced pressure. The thus-obtained crude product was separated by silica gel column chromatography to obtain 10.9g (yield 62%) of intermediate E. The molecular weight of intermediate E as measured by FAB-MS was 362.

Synthesis of intermediate F

Intermediate D (10.0g) was reacted with reactant B (8.77g) by performing the same method as the synthesis method of intermediate E described above to obtain 8.04g (yield 60%) of intermediate F. The molecular weight of intermediate F as measured by FAB-MS was 514.

Synthesis of intermediate G

Intermediate E (8.00g), 2 '-dibromo-1, 1' -biphenyl (13.8g), bis (dibenzylideneacetone) palladium (0) (Pd (dba)₂1.27g), 2-cyclohexylphosphine-2 ',6' -dimethoxybiphenyl (SPhos, 1.81g) and sodium tert-butoxide (NaOtBu, 12.7g) were placed in a 1,000mL three-necked flask and dissolved in toluene (200mL), followed by heating and refluxing for about 12 hours. Then, water is added to the reactionReacting the product, and reacting the mixture with CH₂Cl₂And (4) extracting. The organic layer was collected and MgSO anhydrous₄Dried and the solvent was removed by distillation under reduced pressure. The thus-obtained crude product was separated by silica gel column chromatography to obtain 6.58G (yield 45%) of intermediate G. The molecular weight of intermediate G as measured by FAB-MS was 662.

Synthesis of Compound 1

Intermediate F (5.00G) was reacted with 2,2 '-dibromo-1, 1' -biphenyl (6.06G) by performing the same method as the synthesis method of intermediate G described above to obtain 3.33G (yield 42%) of compound 1. The molecular weight of compound 1 as measured by FAB-MS was 814.

1-2 Synthesis of Compound 2

For example, polycyclic compound 2 can be synthesized by reaction 2 below:

[ reaction 2]

Synthesis of intermediate I

Reactant H (25.0g) was reacted by performing the same method as the synthesis method of intermediate C described above to obtain 15.6g (yield 55%) of intermediate I. The molecular weight of intermediate I as measured by FAB-MS was 384.

Synthesis of intermediate J

Intermediate I (20.0g) was reacted with reactant H (17.6g) by performing the same method as the synthesis of intermediate E described above to obtain 10.7g (yield 40%) of intermediate J. The molecular weight of intermediate J as measured by FAB-MS was 514.

Synthesis of Compound 2

Intermediate J (10.0G) was reacted with 2,2 '-dibromo-1, 1' -biphenyl (12.2G) by performing the same method as the synthesis method of intermediate G described above to obtain 5.38G (yield 34%) of compound 2. The molecular weight of compound 2 as measured by FAB-MS was 814.

1-3, Synthesis of Compound 18 and Compound 19

For example, polycyclic compound 18 and polycyclic compound 19 of the exemplary embodiments can be synthesized by reaction 3 below:

[ reaction 3]

Synthesis of Compound 18

Intermediate G (5.00G), 4-iododibenzofuran (4.44G), copper (I) iodide (CuI, 0.14G), 1, 10-phenanthroline (1,10-Phen, 0.27G) and cesium carbonate (Cs) were added under argon atmosphere₂CO₃12.3g) was placed in a 200mL three-necked flask and dissolved in 1, 2-dichlorobenzene (50mL), followed by heating and stirring at about 190 ℃ for about 8 hours. Adding water to the reaction product and reacting the resulting mixture with CH₂Cl₂And (4) extracting. The organic layer was collected and MgSO anhydrous₄Dried and the solvent was removed by distillation under reduced pressure. The thus-obtained crude product was separated by silica gel column chromatography to obtain 1.88g (yield 25%) of compound 18. The molecular weight of compound 18 as measured by FAB-MS was 995.

Synthesis of Compound 19

Intermediate G (5.00G) was reacted with 4-iododibenzothiophene (4.68G) by performing the same method as the synthetic method of compound 18 described above to obtain 1.55G (yield 20%) of compound 19. Compound 19 had a molecular weight of 1,027 as measured by FAB-MS.

2. Production and evaluation of organic electroluminescent devices comprising polycyclic Compounds

2-1 examples of organic electroluminescent devices comprising polycyclic Compounds

The highest occupied molecular orbital level (hereinafter, HOMO level), the lowest unoccupied molecular orbital level (hereinafter, LUMO level), the lowest excited singlet level (hereinafter, S level) of example compound 1, example compound 2, example compound 18 and example compound 19, comparative compound X-1 and comparative compound X-2, mCP, NPD and 3,3 '-bis (9H-carbazol-9-yl) -1,1' -biphenyl (mCBP) were measured₁Energy level) and the lowest excited triplet level (hereinafter, T)₁Energy level).

Organic electroluminescent devices of examples 1 to 4 and comparative examples 1 and 2, which emit fluorescence, and organic electroluminescent devices of examples 5 to 8 and comparative examples 3 to 5, which emit thermally activated delayed fluorescence, using example compound 1, example compound 2, example compound 18, and example compound 19, and comparative compound X-1 and comparative compound X-2 as materials for a hole transport layer, were manufactured.

Illustrative Compounds

Comparative Compounds

HOMO、LUMO、S₁And T₁Evaluation of energy level

HOMO, LUMO, S by non-empirical molecular orbital method₁And T₁And calculating the energy level. Specifically, the calculation was performed using the Gaussian09 product of wallford gauss, CT, connecticut and using B3LYP as a function and 6-31g (d) as a basis function.

TABLE 1

Compound (I)	HOMO(eV)	LUMO(eV)	S1(eV)	T1(eV)
					Exemplary Compound 1	-5.07	-0.99	3.54	3.01
Exemplary Compound 2	-5.19	-0.90	3.70	3.04
					Exemplary Compound 18	-5.05	-1.20	3.13	3.02
Exemplary Compound 19	-5.04	-1.21	3.12	3.02
					Comparative Compound X-1	-4.91	-0.92	3.19	3.02
Comparative Compound X-2	-4.83	-0.89	3.18	3.08
					mCP	-5.45	-0.75	3.38	3.18
NPD	-4.73	-1.15	3.07	2.47
					mCBP	-5.41	-1.20	3.37	3.15

Fabrication of organic electroluminescent devices

To manufacture each of the organic electroluminescent devices of examples 1 to 4 and comparative examples 1 and 2, ITO was used to form a first electrode EL1 having a thickness of about 150 nm. The hole injection layer HIL having a thickness of about 60nm was formed using 2-TNATA, and the hole transport layer HTL having a thickness of about 30nm was formed using the example compound or the comparative compound. ADN doped with 3% TBP was used to form an emission layer EML having a thickness of about 25 nm. Using Alq₃To form an electron transport layer ETL having a thickness of about 25nm, and an electron injection layer EIL having a thickness of about 1nm, using LiF. Al is used to form the second electrode EL2 having a thickness of about 100 nm. Each layer is formed by a vacuum deposition method. Use of 2-TNATA, TBP, ADN and Alq after sublimation and purification of commercial products₃。

To manufacture the organic electroluminescence of examples 5 to 8 and comparative examples 3 to 5Each of the optical devices, the first electrode EL1 having a thickness of about 150nm was formed using ITO. The hole injection layer HIL having a thickness of about 10nm was formed using HAT-CN, the first hole transport layer having a thickness of about 80nm was formed using NPD, and the second hole transport layer having a thickness of about 5nm was formed using the example compound or the comparative compound. Using a solution doped with 3% 10-phenyl-10H, 10 'H-spiro [ acridine-9, 9' -anthracene]-10' -ketone (ACRSA) to form an emissive layer EML having a thickness of about 25 nm. Using Alq₃To form an electron transport layer ETL having a thickness of about 25nm, and an electron injection layer EIL having a thickness of about 1nm, using LiF. Al is used to form the second electrode EL2 having a thickness of about 100 nm. Each layer is formed by a vacuum deposition method. The compounds HAT-CN, NPD, mCP, mCBP, ACRSA and Alq were used after sublimation and purification of commercial products₃。

Evaluation of Properties of organic electroluminescent device

In order to evaluate the light emitting properties of the organic electroluminescent device thus manufactured, a light emission luminance measuring apparatus C9920-11 of Hamamatsu Photonics Co., Ltd was used. In order to evaluate the properties of the organic electroluminescent devices according to the examples and comparative examples, emission efficiency and luminance half-life were measured. The emission efficiency is about 10mA/cm²The value of current density of (a). Based on a total of from about 1,200cd/m²The time taken for the luminance of (a) to decrease to the extent of 50% thereof shows the luminance half-life. By applying a voltage of about 1.0mA/cm²The drive was continued to measure the current density for the luminance half-life.

The light emitting devices used in examples 1 to 4 and comparative examples 1 and 2 are organic electroluminescent devices that emit blue light as fluorescence. The evaluation results of table 2 are shown based on the emission efficiency and luminance half-life (100%) of comparative example 1 using comparative compound X-1 as a material for a hole transport layer.

The light emitting devices used in examples 5 to 8 and comparative examples 3 to 5 were organic electroluminescent devices emitting blue light as thermally activated delayed fluorescence. The evaluation results of table 3 are shown based on the emission efficiency and luminance half-life (100%) of comparative example 5 using the comparative compound mCP as a material for a hole transport layer.

TABLE 2

TABLE 3

Device fabrication examples	Hole transport layer material	Efficiency of emission	Half life of brightness
				Example 5	Exemplary Compound 1	158％	178％
Example 6	Exemplary Compound 2	141％	175％
				Example 7	Exemplary Compound 18	147％	192％
Example 8	Exemplary Compound 19	147％	200％
				Comparative example 3	Comparative Compound X-1	115％	120％
Comparative example 4	Comparative Compound X-2	110％	130％
				Comparative example 5	mCP	100％	100％

Referring to the results of table 2, in the case of applying the polycyclic compound according to the exemplary embodiment of the invention as a material for a hole transport layer in an organic electroluminescent device, high efficiency and long life may be achieved. Specifically, when compared with comparative example 1 and comparative example 2, it was confirmed that example 1 to example 4 achieved high efficiency and long life.

The comparative compound X-1 comprises four carbazole groups, but does not have a symmetrical structure. Therefore, due to such spatial difference, it was found that the exemplary compound having a symmetric structure has a high hole transporting property. Therefore, it was found that examples 1 to 4 achieve high efficiency and long life as compared with comparative example 1.

Comparative compound X-2 includes four carbazole groups and has symmetry. However, unlike the example compounds in which the carbazolyl group is substituted at the ortho position with respect to the linking group of the bicarbazole core structure, the phenyl group is substituted in the comparative compound X-2. Therefore, due to such spatial difference, it was found that the exemplary compound having a symmetric structure has a high hole transporting property. Therefore, it was found that examples 1 to 4 achieve high efficiency and long life as compared with comparative example 2.

Referring to the results of table 3, in the case of applying the polycyclic compound according to the exemplary embodiment of the invention as a material for a hole transport layer in an organic electroluminescent device, high efficiency and long life may be achieved. Specifically, when compared with comparative examples 3 to 5, it was confirmed that examples 5 to 8 achieved high efficiency and long life.

The example compounds have a similar T when compared to mCBP, which can be used as material for the hole transport layer HTL of organic electroluminescent devices emitting thermally activated delayed fluorescence₁Energy level. Therefore, it is considered that energy emitted from excitons formed in the emission layer is prevented from diffusing to a layer other than the emission layer. In addition, the effect due to the steric structure of the exemplified compounds is increased, and it is considered that the device efficiency and lifetime are increased.

In the case where a material having a HOMO level of about-5.0 eV to about-4.7 eV (such as NPD) is used as the first hole transport layer and a material having a HOMO level of about-5.5 eV to about-5.0 eV (such as the compound of the exemplary embodiment) is used as the material for the second hole transport layer between the first hole transport layer and the emission layer EML, the energy barrier during the transport of holes from the first hole transport layer to the emission layer EML can be relaxed (or referred to as "relaxation"). Therefore, it is considered that high efficiency and long lifetime of the device can also be achieved.

The organic electroluminescent device of at least some exemplary embodiments includes a polycyclic compound including a core structure including an n, n' -bicarbazole moiety and a substituted or unsubstituted carbazolyl group substituted at the core structure. The substituted or unsubstituted carbazolyl group is substituted at any one of a carbon atom at the n + -1 position and a carbon atom at the n '+ -1 position of the n, n' -bicarbazole moiety, respectively. Therefore, the organic electroluminescent device can realize high efficiency and long life. The polycyclic compound can be applied to an organic electroluminescent device to achieve high efficiency and long life.

Organic electroluminescent devices including polycyclic compounds fabricated according to the principles and exemplary embodiments of the invention achieve high efficiency and long lifetime.

Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from the description. The inventive concept is therefore not limited to such embodiments, but is to be defined by the appended claims along with their full scope of various modifications and equivalent arrangements as will be apparent to those skilled in the art.