Novel organic compound for capping layer and organic light-emitting element comprising same
阅读说明：本技术 全新的覆盖层用有机化合物以及包含上述覆盖层用有机化合物的有机发光元件 (Novel organic compound for capping layer and organic light-emitting element comprising same ) 是由 咸昊完 安贤哲 金东骏 李东炫 闵丙哲 李萤振 安慈恩 权桐热 金兑旼 于 2020-09-23 设计创作，主要内容包括：本发明涉及一种覆盖层用有机化合物以及包含上述覆盖层用有机化合物的有机发光元件,上述覆盖层用有机化合物是如苯并唑、苯并噻唑等由被2种以上的元素取代的杂环构成的一个芳胺构成的化合物,上述有机发光元件可以通过包含上述覆盖层用有机化合物而维持无法吸收可见光线区域的较宽的带隙以及高折射率,同时还可以通过增加紫外线区域的吸收波长而具有高色纯度、高效率以及长寿命。(The present invention relates to an organic compound for a cap layer and an organic light-emitting element including the organic compound for a cap layerThe organic compound for the cap layer is, for example, benzo The organic light-emitting element may include the organic compound for a capping layer, and thus may maintain a wide band gap in a region where visible light cannot be absorbed and a high refractive index, and may increase an absorption wavelength in an ultraviolet region, thereby achieving high color purity, high efficiency, and a long lifetime.)
1. A compound for a cap layer represented by chemical formula 1, characterized in that:
chemical formula 1
In the above-described chemical formula 1,
X、X1、X2and X3Each independently is C, CR, O, S, N, Se, Te, NR, CRR ', SiRR' or GeRR ', more than 2 of which are each independently O, S, N, Se, Te, NR, CRR', SiRR 'or GeRR',
r and R 'are each independently hydrogen, deuterium, halogen, nitro, nitrile group, substituted or unsubstituted alkyl group of C1-C30, substituted or unsubstituted alkenyl group of C2-C30, substituted or unsubstituted alkoxy group of C1-C30, substituted or unsubstituted mercapto group of C1-C30, substituted or unsubstituted aryl group of C6-C50, or substituted or unsubstituted heteroaryl group of C2-C50, and a ring may be formed or not by bonding between adjacent R and R' or between a plurality of R,
Ar1and Ar2Each independently is a substituted or unsubstituted aryl group of C6-C50, or a substituted or unsubstituted heteroaryl group of C2-C50,
l is a directly bonded, substituted or unsubstituted arylene of C6-C50, or substituted or unsubstituted heteroarylene of C2-C50.
2. The compound for a cover layer according to claim 1, characterized in that:
the chemical formula 1 is a compound for a cap layer represented by the following chemical formula 2:
chemical formula 2
In the above-described chemical formula 2,
X、X1、X2、X3、Ar1and Ar2As defined in the above chemical formula 1,
R1the same as the definition of R or R' in the above chemical formula 1,
l is an integer of 0 to 5.
3. The compound for a cover layer according to claim 1, characterized in that:
the chemical formula 1 is a compound for a cap layer represented by the following chemical formula 3:
chemical formula 3
In the above-mentioned chemical formula 3,
X1、X2、X3、Ar1and Ar2As defined in the above chemical formula 1,
Ar3with Ar in the above chemical formula 11Or Ar2Are as defined above, however, Ar2And Ar3The sum of the number of carbon atoms of (a) is 50 or less,
R2the same as the definition of R or R' in the above chemical formula 1, m is an integer of 0 to 3.
4. The compound for a cover layer according to claim 3, wherein:
in the above chemical formula 3, Ar2Is biphenyl.
5. The compound for a cover layer according to claim 1, characterized in that:
the chemical formula 1 is a compound for a cap layer represented by the following chemical formula 4:
chemical formula 4
In the above-mentioned chemical formula 4,
X1、X2、X3and Ar2As defined in the above chemical formula 1,
Ar3with Ar in the above chemical formula 11Or Ar2Are as defined above, however, Ar2And Ar3The sum of the number of carbon atoms of (a) is 50 or less,
R2and R3Each independently has the same definition as R or R' in the above chemical formula 1, and m and n are each independently an integer of 0 to 3.
6. The compound for a cover layer according to claim 5, wherein:
in the above chemical formula 4, Ar2Is biphenyl.
7. The compound for a cover layer according to claim 5, wherein:
in the above chemical formula 4, Ar3Is naphthyl.
8. The compound for a cover layer according to claim 1, characterized in that:
the chemical formula 1 is a compound for a cap layer represented by the following chemical formula 5:
chemical formula 5
In the above-mentioned chemical formula 5,
X1、X2and X3As defined in the above chemical formula 1,
R2、R3and R4Each independently of the other is as defined for R or R' in the above chemical formula 1,
m, n and o are each independently an integer of 0 to 3.
9. The compound for a cover layer according to claim 8, wherein:
in chemical formula 5, one or more of m, n, and o are integers of 2 or more.
10. The compound for a cover layer according to claim 1, characterized in that:
x, X as described above1、X2And X3Any one or more of these is O, S or N.
11. The compound for a cover layer according to claim 10, wherein:
x is above1、X2And X3At least one of them is O.
12. The compound for a cover layer according to claim 11, wherein:
x is above1、X2And X3And at least one other of them is N.
13. The compound for a cover layer according to claim 10, wherein:
x is above1、X2And X3At least one of them is S.
14. The compound for a cover layer according to claim 13, wherein:
x is above1、X2And X3And at least one other of them is N.
15. The compound for a cover layer according to claim 1, characterized in that:
r and R' are each independently hydrogen, deuterium, methyl, methoxy, phenyl, or a combination thereof.
16. The compound for a cover layer according to claim 1, characterized in that:
ar above1And Ar2Each independently consisting of phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, triphenylene, carbazolyl, dibenzofuranyl, dibenzothiophenyl, or combinations thereof.
17. The compound for a cover layer according to claim 16, wherein:
ar above1And Ar2One or more of which include naphthyl.
18. The compound for a cover layer according to claim 1, characterized in that:
ar above1And Ar2Each independently includes substituted or unsubstituted fused rings.
19. The compound for a cover layer according to claim 1, characterized in that:
the chemical formula 1 is any one of the following compounds,
20. an organic light-emitting element, comprising:
a1 st electrode and a 2 nd electrode;
an organic layer interposed between the 1 st electrode and the 2 nd electrode; and the number of the first and second groups,
a coating layer disposed outside one or more of the 1 st electrode and the 2 nd electrode, the coating layer containing the compound for coating layer according to any one of claims 1 to 19.
Technical Field
The present invention relates to an organic compound for a capping layer and an organic light-emitting element including the organic compound for a capping layer.
Background
Materials used as an organic layer in an organic light-emitting element can be roughly classified into a light-emitting material, a hole-injecting material, a hole-transporting material, an electron-injecting material, and the like according to their functions.
The light-emitting materials may be classified into fluorescent materials in a singlet excited state derived from electrons and phosphorescent materials in a triplet excited state derived from electrons according to the light-emitting mechanism, and may be classified into blue, green, and red light-emitting materials according to the emission color.
A general organic light emitting device may have a structure in which an anode is formed on a substrate, and a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially formed on the anode. The hole transport layer, the light emitting layer, and the electron transport layer are organic thin films made of organic compounds.
The driving principle of the organic light emitting element structured as described above is as follows.
When a voltage is applied between the anode and the cathode, holes injected from the anode move to the light-emitting layer via the hole transport layer, and electrons injected from the cathode move to the light-emitting layer via the electron transport layer.
The holes and the electrons are recombined in the light emitting layer to generate excitons, and light is generated in a process of converting the excitons from an excited state to a ground state.
The efficiency of an organic light emitting element can be generally classified into internal light emitting efficiency, which is related to the efficiency of generating excitons and realizing light conversion in organic layers interposed between a1 st electrode and a 2 nd electrode, such as a hole transport layer, a light emitting layer, and an electron transport layer, and external light emitting efficiency, and theoretically, the internal light emitting efficiency of fluorescence is 25% and the phosphorescence is 100%.
In addition, the external light emission efficiency refers to the efficiency with which light generated in the organic layer is extracted to the outside of the organic light emitting element, and it has been known that about 20% of the internal light emission efficiency can be extracted to the outside.
As a method for improving the light extraction efficiency, various organic compounds having a refractive index of 1.7 or more are generally used as a capping layer in order to prevent loss of light irradiated to the outside due to total reflection, and in order to improve the performance of an organic light emitting element, development of an organic compound having a high refractive index and thin film stability, which can improve the external light emission efficiency, has been conventionally conducted.
Documents of the prior art
Patent document
(patent document 1) Korean laid-open patent No. 10-2004-0098238
Disclosure of Invention
The object of the present invention is to provide a process for preparing a compound by reacting a compound such as benzeneThe compound for a cover layer of an organic light emitting element, which is capable of improving absorption intensity in an ultraviolet region by using an arylamine compound including 2 or more condensed rings substituted with O, S, N or the like such as oxazole or benzothiazole as a material of the cover layer, improving refractive index by excellent intermolecular thin film arrangement, improving stability to external air or moisture, preventing intermolecular recrystallization, and maintaining stability of the thin film when heat is generated during driving, thereby improving external quantum efficiency and realizing high efficiency, high color purity, and long life, and an organic light emitting element including the organic compound for a cover layer.
As a means for solving the above-mentioned problems,
an embodiment of the present invention provides a compound for a capping layer of an organic light emitting device, represented by the following chemical formula 1.
[ chemical formula 1 ]
In the above-described chemical formula 1,
X、X1、X2and X3Each independently is C, CR, O, S, N, Se, Te, NR, CRR ', SiRR' or GeRR ', more than 2 of which are each independently O, S, N, Se, Te, NR, CRR', SiRR 'or GeRR',
wherein R and R ' are each independently hydrogen, deuterium, halogen, nitro, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C1-C30 mercapto group, substituted or unsubstituted C6-C50 aryl group, or substituted or unsubstituted C2-C50 heteroaryl group, and a ring may or may not be formed by bonding between adjacent R and R ' or between a plurality of R's,
Ar1and Ar2Each independently substituted or unsubstitutedAryl of C6-C50, or substituted or unsubstituted heteroaryl of C2-C50,
l is a directly bonded, substituted or unsubstituted arylene of C6-C50, or substituted or unsubstituted heteroarylene of C2-C50.
Further, another embodiment of the present invention provides an organic light emitting element including: a1 st electrode; a 2 nd electrode; an organic layer interposed between the 1 st electrode and the 2 nd electrode; and a covering layer disposed outside one or more of the 1 st electrode and the 2 nd electrode, the covering layer containing the compound for covering layer.
The compound for the covering layer according to an embodiment of the present invention is, for example, benzoArylamine compounds including 2 or more fused rings substituted with O, S, N or the like elements such as oxazole and benzothiazole can exhibit high color purity by maintaining a wide band gap in a region where visible light cannot be absorbed.
In addition, the absorption wavelength of the ultraviolet region can be increased while maintaining a high refractive index.
In addition, external quantum efficiency can be improved and stability can be maintained upon exposure to ultraviolet rays.
In addition, the film has excellent intermolecular alignment, and can improve the refractive index and the stability to the external air and moisture.
In addition, it is possible to prevent recrystallization between molecules by the higher Tg and Td, and also to maintain the stability of the thin film when heat is generated during driving.
Drawings
Fig. 1 is a sectional view schematically illustrating the configuration of an organic light emitting element according to an embodiment of the present invention.
Fig. 2 is a graph illustrating the result of the evaluation of the absorption intensity of the ultraviolet region according to the embodiment of the present invention.
[ notation ] to show
100: substrate
200: hole injection layer
300: hole transport layer
400: luminescent layer
500: electron transport layer
600: electron injection layer
1000: 1 st electrode
2000: 2 nd electrode
3000: covering layer
Detailed Description
Before explaining the present invention in detail, it is to be understood that the terminology used in the description is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the scope of the appended claims. Unless otherwise specifically stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.
Throughout this specification and the claims which follow, unless the context clearly dictates otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated item, step, or series of items or steps but not the exclusion of any other item, step, or series of items or steps.
Throughout this specification and the claims, the term "aryl" is meant to include, for example, phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylene, phenylene, perylene, and,Fluoro, fluoranthenyl, benzofluorenyl, benzotrriphenylene, benzoAryl group of C5-50 of aromatic ring such as aryl, anthracenyl, stilbenyl and pyrenyl, and "heteroaryl" refers to the group including pyrrolyl, pyrazinyl, pyridyl, indolyl, isoindolyl, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, benzeneAnd a thienyl group, a dibenzothienyl group, a quinolyl group, an isoquinolyl group, a quinoxalyl group, a carbazolyl group, a phenanthridinyl group, an acridinyl group, a phenanthrolinyl group, a thienyl group, and a pyridyl ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an indole ring, a quinoline ring, an acridine ring, a pyrrolidine ring, a bisquinoline ring, a quinoxaline ring, a phenanthroline ring, a thienyl group, a phenanthridine ring, aAn alkyl ring, a piperidine ring, a morpholine ring, a piperazine ring, a carbazole ring, a furan ring, a thiophene ring,An azolyl ring,Diazole ring, benzoAn aromatic ring of C3-50 including at least one hetero element, which is a heterocyclic group consisting of an azole ring, a thiazole ring, a thiadiazole ring, a benzothiazole ring, a benzotriazole ring, an imidazole ring, a benzimidazole ring, a pyran ring, and a dibenzofuran ring.
Throughout the present specification and claims, the term "substituted or unsubstituted" means substituted or unsubstituted with one or more groups selected from the group consisting of deuterium, halogen, amino group, nitro group, nitrile group, alkyl group of C1 to C30, alkenyl group of C2 to C30, alkoxy group of C1 to C30, cycloalkyl group of C3 to C20, heteroalkyl group of C3 to C20, aryl group of C6 to C30, heteroaryl group of C3 to C30, and the like. In addition, throughout the specification of the present application, the same symbols have the same meaning unless explicitly stated otherwise.
Moreover, various embodiments of the invention may be combined with other certain embodiments, unless explicitly stated to the contrary. Next, embodiments of the present invention and effects thereof will be explained.
Specific examples of the compound for a cap layer of the present invention include compounds for a cap layer represented by the following chemical formula 1.
[ chemical formula 1 ]
In the above-described chemical formula 1,
X、X1、X2and X3Each independently is C, CR, O, S, N, Se, Te, NR, CRR ', SiRR' or GeRR ', more than 2 of which are each independently O, S, N, Se, Te, NR, CRR', SiRR 'or GeRR',
wherein R and R ' are each independently hydrogen, deuterium, halogen, nitro, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C1-C30 mercapto group, substituted or unsubstituted C6-C50 aryl group, or substituted or unsubstituted C2-C50 heteroaryl group, and a ring may or may not be formed by bonding between adjacent R and R ' or between a plurality of R's,
Ar1and Ar2Each independently is a substituted or unsubstituted aryl group of C6-C50, or a substituted or unsubstituted heteroaryl group of C2-C50,
l is a directly bonded, substituted or unsubstituted arylene of C6-C50, or substituted or unsubstituted heteroarylene of C2-C50.
The compound for a capping layer of the present invention is an arylamine compound including 2 or more condensed rings substituted with O, S, N or the like, and when applied to a capping layer of an organic light-emitting device, can exhibit high color purity by maintaining a wide band gap in a region where visible light cannot be absorbed, and can improve external quantum efficiency and maintain stability when exposed to ultraviolet light.
In addition, it is possible to prevent recrystallization between molecules by the higher Tg and Td, and also to maintain the stability of the thin film when heat is generated during driving.
Further, specific examples of the compound for a cap layer according to the present invention include compounds for a cap layer represented by the following chemical formula 2.
[ chemical formula 2 ]
In the above-described chemical formula 2,
X、X1、X2、X3、Ar1and Ar2As defined in the above chemical formula 1,
R1the same as the definition of R or R' in the above chemical formula 1,
l is an integer of 0 to 5. Specifically, l may be 1 or more.
In the compound for a cover layer of the present invention as described above, 2 or more condensed rings substituted with an element such as O, S, N are bonded to an amine directly or through 1 or more phenylene groups, so that a high refractive index can be maintained.
In particular, in the case where l is 1 or more, the absorption wavelength in the blue region can be minimized by the phenylene group adjacent to the amine, and at the same time, the refractive index can be effectively improved.
Further, specific examples of the compound for a cover layer of the present invention include a compound for a cover layer of the following chemical formula 3.
[ chemical formula 3 ]
In the above-mentioned chemical formula 3,
X1、X2、X3、Ar1and Ar2As defined in the above chemical formula 1,
Ar3with Ar in the above chemical formula 11Or Ar2Are as defined above, however, Ar2And Ar3The sum of the number of carbon atoms of (a) is 50 or less,
R2the same as the definition of R or R' in the above chemical formula 1,
m is an integer of 0 to 3. Specifically, m may be 1 or more.
In the compound for a cover layer of the present invention, X in the condensed ring is C or CH, and the condensed ring is bonded to an amine directly or via 1 or more 1, 4-phenylene groups, thereby maintaining a high refractive index.
In particular, in the case where m is 1 or more, it is possible to increase the absorption wavelength of the ultraviolet region while having a high refractive index, thereby improving stability upon exposure to external ultraviolet rays.
More specifically, Ar in the above chemical formula 32-Ar3A minimum of 3 or more aryl or heteroaryl groups may be included, as examples of which Ar2May be a biphenyl group. In the case described above, a higher refractive index can be obtained, and an effect of increasing the absorption in the ultraviolet region can also be achieved.
Further, specific examples of the compound for a cover layer of the present invention include a compound for a cover layer of the following chemical formula 4.
[ chemical formula 4 ]
In the above-mentioned chemical formula 4,
X1、X2、X3and Ar2As defined in the above chemical formula 1,
Ar3with Ar in the above chemical formula 11Or Ar2Are as defined above, however, Ar2And Ar3The sum of the number of carbon atoms of (a) is 50 or less,
R2and R3Each independently of the other is as defined for R or R' in the above chemical formula 1,
m and n are each independently an integer of 0 to 3. Specifically, m and n may be 1 or more.
In the compound for a cover layer of the present invention as described above, X in the condensed ring is C or CH, and includes 2 or more condensed rings as described above. In addition, 2 fused rings are each bonded to an amine directly or via 1 or more 1, 4-phenylene groups, whereby a high refractive index can be maintained.
In particular, in the case where m and n are 1 or more, it is possible to increase the absorption wavelength of the ultraviolet region while having a high refractive index, thereby improving stability upon exposure to external ultraviolet rays.
More specifically, Ar in the above chemical formula 42-Ar3A minimum of 3 or more aryl or heteroaryl groups may be included, as examples of which Ar2May be a biphenyl group. In the case as described above, with Ar2-Ar3The case where 1 or 2 aryl groups are included, such as phenyl or biphenyl, can have a higher refractive index than the case where the ultraviolet region is increased.
More specifically, Ar in the above chemical formula 43May be a naphthyl group. In the case of including the naphthyl group as described above, it is possible to have a higher refractive index and maintain a lower deposition temperature, so that thermal stability can be effectively improved.
Further, specific examples of the compound for a cover layer of the present invention include a compound for a cover layer of the following chemical formula 5.
[ chemical formula 5 ]
In the above-mentioned chemical formula 5,
X1、X2and X3As defined in the above chemical formula 1,
R2、R3and R4Each independently of the other is as defined for R or R' in the above chemical formula 1,
m, n and o are each independently an integer of 0 to 3. Specifically, m, n, and o may be 1 or more.
In the compound for a cover layer of the present invention as described above, X in the condensed ring is C or CH, and includes 3 condensed rings as described above. In addition, 3 fused rings are each bonded to an amine directly or via 1 or more 1, 4-phenylene groups, whereby a high refractive index can be maintained.
In particular, in the case where m, n, and o are 1 or more, it is possible to increase the absorption wavelength of the ultraviolet region while having a high refractive index, thereby improving stability upon exposure to external ultraviolet rays.
More specifically, one or more of m, n, and o may be 2 or more, and in the case described above, the refractive index may be higher, and the effect of increasing the absorption in the ultraviolet region may be achieved.
The compound for a cap layer of the present invention, which is composed of any one of the above chemical formulas 3 to 5, can increase the absorption wavelength of the ultraviolet region while having a high refractive index, thereby improving stability upon exposure to external ultraviolet rays, and can also minimize absorption of the blue region, thereby contributing to realization of high efficiency and high color purity.
As a specific example compound of the compound for a covering layer of the present invention, in any one of chemical formulas 1 to 5, X, X1、X2And X3May be comprised of O, S or N. Thereby, the bonding length of the hetero atom can be minimized, thereby achieving the effect of reducing the volume characteristic.
Specifically, X, X in any one of the above chemical formulas 1 to 51、X2And X3One or more of them may be composed of O. Thereby, the deposition temperature can be effectively lowered by reducing the molecular weight while maintaining a high refractive index.
More specifically, in any one of the above chemical formulas 1 to 5, X1、X2And X3One or more of them is O, and the other or more may be constituted by N. In the case where each of O and N is included at least 1 or more as described above, the absorption of the visible ray region can be minimized, so that the color purity can be effectively improved and the deposition temperature can be maintained low.
Further, in the above chemical formulas 1 to 5X, X in any one of (1)1、X2And X3May be constituted by S. Thereby, the glass transition temperature (Tg) value can be higher while the refractive index is high, thereby being beneficial to forming a stable film.
Specifically, in any one of the above chemical formulas 1 to 5, X1、X2And X3One or more of S, and the other or more may be constituted by N. In the case where each of O and S includes 1 or more at minimum as described above, it is possible to absorb a wider ultraviolet region and effectively improve the refractive index.
Specific examples of the compound for a coating layer according to the present invention include compounds represented by any one of chemical formulas 1 to 5, wherein R, R' and R are as described above1、R2、R3And R4Each independently may be composed of hydrogen, deuterium, methyl, methoxy, phenyl, or a combination thereof. The compound of the present invention as described above can have a high refractive index by minimizing the volume characteristics of the substituent, can also increase the absorption in the ultraviolet region, and can exhibit a high refractive index because the intermolecular thin film arrangement is excellent.
As specific illustrative compounds of the compound for a covering layer of the present invention, in any one of chemical formulas 1 to 5, Ar mentioned above1To Ar3Each independently can be comprised of phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, triphenylene, carbazolyl, dibenzofuranyl, dibenzothiophenyl, or combinations thereof. The compound of the present invention as described above can have a high refractive index by minimizing the volume characteristics of the substituent, can also increase the absorption in the ultraviolet region, and can exhibit a high refractive index because the intermolecular thin film arrangement is excellent.
Specifically, Ar is1To Ar3One or more of which may include a naphthyl group. The compounds of the present invention as described above can have a higher Tg and a lower deposition temperature while maintaining a high refractive index.
Specific examples of the coating layer-forming compound of the present inventionExemplified compounds of any one of chemical formulas 1 to 5, Ar described above1To Ar3May be represented by any one of the following structural formulae B-1 to B-7, each independently.
In the above B-1 to B-7, q is an integer of 0 to 5.
Specifically, Ar is1To Ar3May each independently be one of the above structural formulae B-2 to B-7, and may include a substituted or unsubstituted condensed ring formed by condensation of 2 or more rings as described above. Further, q in this case may be an integer of 2 or more.
As a specific example compound of the compound for a cover layer of the present invention, the above chemical formula 1 may be represented by any one of the following compounds.
An example of the compound for a cover layer of the present invention may be formed by amination, and its general reaction formula is shown below.
Next, an organic light emitting element according to an embodiment of the present invention will be described in detail.
According to an embodiment of the present invention, the organic light emitting element may include a1 st electrode, a 2 nd electrode, an organic layer interposed between the 1 st electrode and the 2 nd electrode, and a cover layer, and the cover layer may be disposed outside any one or more of the 1 st electrode and the 2 nd electrode.
Specifically, the thickness of the cover layer may be 100 to 100
Among both side surfaces of the 1 st electrode or the 2 nd electrode, a side adjacent to the organic layer interposed between the 1 st electrode and the 2 nd electrode is referred to as an inner side, and a side not adjacent to the organic layer is referred to as an outer side. That is, when the capping layer is disposed outside the 1 st electrode, the 1 st electrode will be interposed between the capping layer and the organic layer, and when the capping layer is disposed outside the 2 nd electrode, the 2 nd electrode will be interposed between the capping layer and the organic layer.
According to an embodiment of the present invention, the organic light emitting device may include a plurality of organic layers of 1 layer or more on the inner sides of the 1 st electrode and the 2 nd electrode, and a cover layer may be formed on the outer side of any one or more of the 1 st electrode and the 2 nd electrode. That is, the cover layer may be formed on the outer side of the 1 st electrode and the outer side of the 2 nd electrode at the same time, or may be formed only on the outer side of the 1 st electrode or the outer side of the 2 nd electrode.
Further, the above-mentioned coating layer may include the compound for coating layer according to the present invention, may include the compound for coating layer according to the present invention alone, or may include two or more or a combination of known compounds.
The organic layer may include a hole transport layer, a light emitting layer, and an electron transport layer, which generally constitute the light emitting section, but is not limited thereto.
Specifically, the organic light emitting element according to an embodiment of the present invention may include 1 or more organic layers constituting a light emitting portion such as a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an emission layer (EML), an Electron Transport Layer (ETL), and an Electron Injection Layer (EIL) between a1 st electrode (anode) and a 2 nd electrode (cathode).
Fig. 1 is a sectional view schematically illustrating the configuration of an organic light emitting element according to an embodiment of the present invention. An organic light emitting element according to an embodiment of the present invention may be manufactured in a structure as shown in fig. 1.
The organic light emitting element may be formed by sequentially stacking a substrate 100, a capping layer 3000, a1 st electrode 1000, a hole injection layer 200, a hole transport layer 300, a light emitting layer 400, an electron transport layer 500, an electron injection layer 600, a 2 nd electrode 2000, and a capping layer 3000 in this order from below.
As the substrate 100, a substrate generally used for an organic light-emitting element can be used, and in particular, a transparent glass substrate or a flexible plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, handling convenience, and water resistance can be used.
The 1 st electrode 1000 is used as a hole injection electrode for injecting holes in the organic light emitting device. The 1 st electrode 1000 is manufactured using a material having a low work function to inject holes, and may be formed of a transparent material such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), or graphene (graphene).
The hole injection layer 200 may be formed by depositing a hole injection layer material on the 1 st electrode 1000 by a method such as a vacuum deposition method, a spin coating method, a casting method, and a Langmuir-Blodgett (LB) method. When the hole injection layer 200 is formed by the vacuum deposition method, the deposition conditions vary depending on the compound used as the material of the hole injection layer 200, the desired structure and thermal characteristics of the hole injection layer 200, and the deposition temperature of 50 to 500 ℃ and the deposition temperature of 10 ℃ may be generally used-8To 10-3Vacuum degree of torr (torr) of 0.01 toDeposition rate per second andthe layer thickness is suitably selected within the range of 5 μm. Further, a charge generation layer may be additionally deposited on the surface of the hole injection layer 200 as needed. As the charge generation layer material, a general material, for example, hexacyano-Hexaazatriphenylene (HATCN) can be used.
Next, the hole transport layer 300 may be formed by depositing a hole transport layer material on the hole injection layer 200 by a method such as a vacuum deposition method, a spin coating method, a casting method, or a langmuir-blodgett (LB) method. In the case of forming the hole transport layer 300 by the above-described vacuum deposition method, the deposition conditions thereof will vary depending on the compound used, but are generally selected within the range of conditions almost the same as those for forming the hole injection layer 200. The hole transport layer 300 can be formed using a known compound. The hole transport layer 300 may be 1 or more layers as described above, and although not shown in fig. 1, an emission assist layer may be additionally formed on the hole transport layer 300.
The light-emitting layer 400 can be formed by depositing a light-emitting material on the hole transport layer 300 or the light-emitting auxiliary layer by a method such as a vacuum deposition method, a spin coating method, a casting method, or a langmuir-blodgett (LB) method. When the light-emitting layer 400 is formed by the vacuum deposition method, the deposition conditions may vary depending on the compound used, but are generally selected within the range of conditions almost the same as those for forming the hole-injecting layer 200. As the material of the light-emitting layer, a known compound can be used as a host or a dopant.
In addition, when a phosphorescent dopant is simultaneously used in the material of the light emitting layer, a hole blocking material (HBL) may be additionally stacked on the upper portion of the light emitting layer 400 by a vacuum deposition method or a spin coating method in order to prevent a phenomenon that triplet excitons or holes are diffused into the electron transporting layer 500. The hole-blocking material used in this case is not particularly limited, and any known material can be selected and used. For example, it is possible to useOxadiazole derivatives, benzotriazole derivatives, phenanthroline derivatives, or the hole-blocking materials described in Japanese unexamined patent publication No. 11-329734(A1), and the most typical examples thereof include Balq (bis (8-hydroxy-2-methylquinoline) - (4-phenylphenoxy) aluminum), phenanthroline compounds (e.g., BCP (bathocuproine) available from UDC). The light-emitting layer 400 of the present invention may include 1 or more or 2 or more blue light-emitting layers.
The electron transport layer 500 is formed on the light emitting layer 400, and may be formed by a vacuum deposition method, a spin coating method, a casting method, or the like. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally selected to be within almost the same range as the conditions for forming the hole injection layer 200.
The electron injection layer 600 may be formed by depositing an electron injection layer material on the electron transport layer 500, and may be formed by a vacuum deposition method, a spin coating method, a casting method, or the like.
The hole injection layer 200, the hole transport layer 300, the light-emitting layer 400, and the electron transport layer 500 of the organic light-emitting device can be produced using the following materials, but are not limited thereto.
The 2 nd electrode 2000 is used as an electron injection electrode, and may be formed on the electron injection layer 600 by a vacuum deposition method, a spin coating method, or the like. As a material of the 2 nd electrode 2000, various metals can be used. As specific examples, substances such as aluminum, gold, silver, magnesium, and the like are included, but not limited thereto.
The organic light emitting device of the present invention may be an organic light emitting device having various structures, including the capping layer 3000, the 1 st electrode 1000, the hole injection layer 200, the hole transport layer 300, the light emitting layer 400, the electron transport layer 500, the electron injection layer 600, the 2 nd electrode 2000, and the capping layer 3000, as described above, or may be an organic light emitting device including 1 or 2 additional intermediate layers, as necessary.
Further, the thickness of each organic layer formed by the present invention may be adjusted to a desired degree, specifically, 10 to 1000nm, more specifically, 20 to 150 nm.
As shown in fig. 1, the cover layer 3000 may be formed on an outer surface of both side surfaces of the 1 st electrode 1000 on which the hole injection layer 200 is not formed. Further, the outer surface on which the electron injection layer 600 is not formed may be formed on both side surfaces of the 2 nd electrode 2000, but is not limited thereto. The capping layer 3000 as described above may be formed by deposition engineering, and the thickness of the capping layer 3000 may be 100 to 100 aMore specifically, it may be 300 to 300The problem of the decrease in the transmittance of the cover layer 3000 can be prevented by the thickness adjustment method described above.
Although not shown in fig. 1, according to an embodiment of the present invention, an organic layer for performing various functions may be additionally formed between the capping layer 3000 and the 1 st electrode 1000 or between the capping layer 3000 and the 2 nd electrode 2000. Alternatively, an organic material layer for performing various functions may be additionally formed on the upper portion (outer surface) of the cover layer 3000, but the present invention is not limited thereto.
Next, an organic light emitting element including a capping layer according to an embodiment of the present invention will be described in detail with reference to manufacturing examples and embodiments. The following production examples and examples are merely illustrative of the present invention, and the scope of the present invention is not limited to the following production examples and examples.
<Production example 1>Synthesis of Compound 13
2- (4-bromophenyl) benzo [ d ] using a round-bottom flask]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole)2.0g, 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine)4.0g、t-BuONa 1.0g、Pd2(dba)3 0.3g、(t-Bu)30.3ml of P was dissolved in 100ml of toluene and then stirred under reflux. The reaction was confirmed by Thin Layer Chromatography (TLC) and was terminated after the addition of water. The organic layer was extracted with MC (Methylene chloride) and recrystallized after filtration under reduced pressure, thereby obtaining 3.6g of compound 13 (yield 71%).
m/z：690.27(100.0％)、691.27(55.6％)、692.27(15.6％)、693.28(2.7％)
<Production example 2>Synthesis of Compound 61
The preparation was carried out in the same manner as in preparation example 1, except that 4- (naphthalen-2-yl) aniline (4- (naphthalen-2-yl) aniline) was used in place of 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ] -4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ] -4-amine) to synthesize compound 61. (yield 68%)
m/z：605.21(100.0％)、606.21(46.6％)、607.22(10.2％)、608.22(1.7％)
<Production example 3>Synthesis of Compound 62
The preparation was carried out in the same manner as in preparation example 1, except that 4'- (naphthalen-2-yl) - [1,1' -biphenyl ] -4-amine (4'- (naphthalen-2-yl) - [1,1' -biphenyl ] -4-amine) was used in place of 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ] -4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ] -4-amine) to synthesize compound 62. (yield 65%)
m/z：681.24(100.0％)、682.24(53.0％)、683.25(13.8％)、684.25(2.6％)
<Production example 4>Synthesis of Compound 166
The preparation was carried out in the same manner as in preparation example 1, using 2- (4-bromophenyl) benzo [ d ]]Thiazole (2- (4-bromophenyl) benzol [ d ]]thiamazole) and bis (4- (naphthalen-2-yl) phenyl) amine (bis (4- (naphthalen-2-yl) phenyl) amine) in place of 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) and 4' - (naphthalen-2-yl) -N-(4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine) Compound 166 was synthesized. (yield 66%)
m/z：630.21(100.0％)、631.22(49.0％)、632.22(12.1％)、632.21(4.9％)、633.21(2.2％)、633.22(2.0％)、631.21(1.5％)
<Production example 5>Synthesis of Compound 169
The preparation was carried out in the same manner as in preparation example 1, using 2- (4-bromophenyl) benzo [ d ]]Thiazole (2- (4-bromophenyl) benzol [ d ]]thiazole) substituted for 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) compound 169 was synthesized. (yield 63%)
m/z：706.24(100.0％)、707.25(55.6％)、708.25(15.6％)、708.24(4.9％)、709.25(2.9％)、709.24(2.5％)、707.24(1.5％)
<Production example 6>Synthesis of Compound 70
The preparation was carried out in the same manner as in preparation example 1, using bis (4- (benzo [ d ])]Azol-2-yl) phenyl amine (bis (4- (benzol [ d ]))]oxazol-2-yl) phenyl) amine) and 2- (4'-bromo- [1,1' -biphenyl]-4-yl) benzo [ d]Azole (2- (4'-bromo- [1,1' -biphenyl)]-4-yl)benzo[d]oxazole) in place of 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) and 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine) Compound 70 was synthesized. (yield 71%)
m/z：672.22(100.0％)、673.22(49.1％)、674.22(13.0％)、675.23(1.8％)、673.21(1.5％)
<Production example 7>Synthesis of Compound 58
The preparation was carried out in the same manner as in preparation example 1, using bis (4- (benzo [ d ])]Azol-2-yl) phenyl amine (bis (4- (benzol [ d ]))]oxazol-2-yl) phenyl) amine) and 4-bromo-1,1'-biphenyl (4-bromo-1,1' -biphenyl) in place of 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) and 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine) Compound 58 was synthesized. (yield 64%)
m/z：555.19(100.0％)、556.20(41.5％)、557.20(9.2％)、558.20(1.3％)、556.19(1.1％)
<Production example 8>Synthesis of Compound 59
The preparation was carried out in the same manner as in preparation example 1, using bis (4- (benzo [ d ])]Azol-2-yl) phenyl amine (bis (4- (benzol [ d ]))]oxazol-2-yl) phenyl) amine) and 4-bromo-1,1':4',1 '-terphenyl (4-bromo-1,1':4', 1' -terphenyl) instead of 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) and 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine) Compound 59 was synthesized. (yield 59%)
m/z：631.23(100.0％)、632.23(48.0％)、633.23(12.0％)、634.24(1.7％)、632.22(1.1％)
<Production example 9>Synthesis of Compound 69
The preparation was carried out in the same manner as in preparation example 1, using bis (4- (benzo [ d ])]Azol-2-yl) phenyl amine (bis (4- (benzol [ d ]))]oxazol-2-yl) phenyl) amine) and 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) in place of 2- (4-bromophenyl) benzo [ d]Oxazole (2- (4-bromophenyl) benzol [ d]oxazole) and 4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl]-4-amine (4'- (naphthalen-2-yl) -N- (4- (naphthalen-2-yl) phenyl) - [1,1' -biphenyl ]]-4-amine) Compound 69 was synthesized. (yield 56%)
m/z：596.18(100.0％)、597.19(42.6％)、598.19(10.1％)、599.19(1.6％)、597.18(1.5％)
Manufacture of organic light-emitting element
An organic light-emitting element was manufactured in the structure described in fig. 1, but a part of the layers was omitted as described below, and a cap layer 3000 was formed only on the upper portion. Specifically, the organic light emitting device is manufactured by sequentially laminating the 1 st electrode 1000, the hole injection layer 200, the hole transport layer 300, the light emitting layer 400, the electron transport layer 500, the electron injection layer 600, the 2 nd electrode 2000, and the cover layer 3000 in this order from below. The substances shown in table 1 below were applied to the hole injection layer 200, the hole transport layer 300, the light-emitting layer 400, and the electron transport layer 500.
[ TABLE 1 ]
<Example 1>Manufacture of organic light-emitting element
Over an Indium Tin Oxide (ITO) substrate formed with a reflective layer containing Ag, a hole injection layer HI01 was formedHATCNHole transport layer HT01After the deposition, the light-emitting layer was doped with BH01: BD 013%Film formation is performed. Next as an electron transport layer ET01: Liq (1:1)Deposition of LiF after film formationThereby forming an electron injection layer. MgAg was then deposited in a thickness of 15nm, and the compound produced in production example 1 was then coated over the cathode as a coating layerIs deposited to a thickness of (a). The organic light-emitting element was manufactured by encapsulating (Encapsulation) the above-described element in a glove box.
<Examples 2 to 9>Manufacture of organic light-emitting element
The organic light-emitting device was manufactured in the same manner as in example 1, and after the cover layer was formed using the compounds manufactured in production examples 2 to 9, respectively.
< comparative examples 1 to 3>
The organic light-emitting device was manufactured in the same manner as in example 1, and the cover layer was formed by comparative example 1(ref.1) to comparative example 3(ref.3) shown in table 2 below.
[ TABLE 2 ]
< test example 1> evaluation of performance of organic light emitting element
The performance of the organic light emitting devices according to examples 1 to 9 and comparative examples 1 to 3, i.e., the current density and the luminance with respect to the applied voltage, were evaluated under atmospheric pressure conditions by applying a voltage to a gieviy 2400 source measurement unit (kinetey 2400 source measurement unit) to inject electrons and holes and measuring the luminance when light is emitted using a Konica Minolta (Konica Minolta) spectroradiometer (CS-2000), and the results are shown in table 3.
[ TABLE 3 ]
Op.V
mA/cm2
Cd/A
CIEx
CIEy
LT97
Example 1
3.40
10
7.81
0.139
0.044
185
Example 2
3.41
10
7.56
0.141
0.045
177
Example 3
3.40
10
7.84
0.140
0.044
183
Example 4
3.41
10
8.01
0.139
0.044
170
Example 5
3.40
10
8.17
0.140
0.043
175
Example 6
3.40
10
8.29
0.140
0.042
190
Example 7
3.41
10
7.34
0.138
0.047
161
Example 8
3.41
10
7.57
0.141
0.045
175
Example 9
3.41
10
7.60
0.141
0.045
178
Comparative example 1
3.41
10
6.72
0.131
0.054
73
Comparative example 2
3.42
10
7.05
0.130
0.050
111
Comparative example 3
3.41
10
6.92
0.133
0.052
105
By comparing the examples of the present invention, it can be found that the present invention can be obtained by benzoThe combination of oxazole and benzothiazole with one aromatic amine minimizes the volume characteristics and has a high refractive index, while also increasing the absorption wavelength of the ultraviolet region and effectively improving the efficiency and lifetime of the organic light emitting element with a higher Tg. In addition, compared to comparative example 3, the polarizability can be improved by substitution with 2 or more hetero elements and a stable thin film can be formed by excellent film arrangement between molecules, so that the refractive index can be effectively improved even with a small molecular weight and thereby an organic light emitting element with high color purity, high efficiency, and long lifetime can be realized.
< test example 2> evaluation of refractive index
Using the compounds of production examples 1, 3 and 5 and the compounds of comparative example 1(ref.1), comparative example 2(ref.2) and comparative example 3(ref.3), respectively, a deposited film having a thickness of 30nm was produced on a silicon substrate by a vacuum deposition apparatus, and then the refractive index at 450nm was measured by an ellipsometer apparatus (j.a. woollam co.inc, M-2000X). The results are shown in table 4 below.
[ TABLE 4 ]
As shown in table 4, it was confirmed that the compounds of production examples 1, 3 and 5 of the present invention exhibited high refractive indices of 2.30 or more, specifically 2.35 or more, more specifically 2.4 or more.
< test example 3> evaluation of absorption intensity in ultraviolet region
In the ultraviolet region, a deposited film having a thickness of 30nm was formed on a silicon substrate by a vacuum deposition apparatus using the compound of production examples 1 (compound 13) and 3 (compound 62) and the compound of comparative example 1(ref.1), respectively, and then the absorption wavelength in the range of 250nm to 1000nm was measured by an ellipsometer apparatus (j.a. woollam co.inc, M-2000X). The results are shown in FIG. 2.
It was confirmed that the absorption intensity of the compounds of production examples 1 and 3 of the present invention was 0.8 or more, specifically 0.9 or more in the ultraviolet absorption region of 380nm, and that the absorption intensity was improved by 30% or more, specifically 50% or more, compared with the compound of comparative example (ref.1).
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