Novel covering layer compound and organic light emitting element comprising the same

Abstract

The present application provides a compound for a cladding layer represented by the following Chemical Formula 1 and an organic light emitting element comprising the compound for a cladding layer.

Description

Technical Field

[0001] This invention relates to a compound for a coating layer and an organic light-emitting element comprising the aforementioned compound for a coating layer. Background Technology

[0002] Materials used as organic layers in organic light-emitting elements can be broadly classified according to their function into light-emitting materials, hole injection materials, hole transport materials, electron transport materials, and electron injection materials.

[0003] In addition, the above-mentioned luminescent materials can be classified according to their luminescence mechanism into fluorescent materials derived from the singlet excited state of electrons and phosphorescent materials derived from the triplet excited state of electrons. They can also be classified according to their luminescence color into blue, green, and red luminescent materials.

[0004] A typical organic light-emitting device (OLED) can be constructed by forming an anode on a substrate, and then sequentially forming a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode on top of the anode. The hole transport layer, the light-emitting layer, and the electron transport layer are organic thin films composed of organic compounds.

[0005] The driving principle of the organic light-emitting element with the structure described above is as follows.

[0006] When a voltage is applied between the anode and cathode, holes injected from the anode will move to the light-emitting layer via the hole transport layer, while electrons injected from the cathode will move to the light-emitting layer via the electron transport layer. These holes and electrons will then recombine in the light-emitting layer to generate excitons.

[0007] During the process of excitons transitioning from the excited state to the ground state, light is generated. The efficiency of organic light-emitting devices can generally be divided into internal luminous efficiency and external luminous efficiency. Internal luminous efficiency is related to the efficiency of generating excitons and achieving light conversion in organic layers such as hole transport layers, light-emitting layers, and electron transport layers between the first and second electrodes. Theoretically, the internal luminous efficiency of fluorescence is 25%, while that of phosphorescence is 100%.

[0008] Furthermore, external luminous efficiency refers to the efficiency with which light generated in the organic layer is extracted to the outside of the organic light-emitting element. It is known that approximately 20% of the internal luminous efficiency can typically be extracted to the outside. As a method to improve the light extraction efficiency, to prevent the loss of light illuminating the outside due to total internal reflection, various organic compounds with a refractive index of 1.7 or higher are commonly used as a capping layer. Moreover, in order to improve the performance of organic light-emitting elements, efforts have been made to develop an organic compound with a high refractive index and thin film stability that can improve external luminous efficiency. Summary of the Invention

[0009] The purpose of this invention is to provide a compound for a cover layer of an organic light-emitting element, which is an aromatic amine compound containing one or more nitrogen (N) in the form of indoleazine or imidazopyridine, and which can improve the absorption wavelength in the ultraviolet region while having a wide band gap and high refractive index in the region where it is difficult to absorb visible light, thereby achieving high color purity, high efficiency and long service life, as well as an organic light-emitting element containing the above-mentioned cover layer compound.

[0010] Furthermore, the present invention aims to provide a coating compound and an organic light-emitting element that can improve the refractive index by optimizing the thin film arrangement between molecules, and can prevent recrystallization between molecules by using a higher glass transition temperature (Tg) and dew point temperature (Td) to maintain the stability of the thin film when heat is generated during the driving process. It can also improve the stability by protecting the element from the influence of external air and moisture, thereby improving the external quantum efficiency and significantly improving the service life.

[0011] Next, we will provide a detailed explanation of the topics mentioned above, as well as any additional topics.

[0012] To address the aforementioned issues, in one embodiment of the present invention,

[0013] A compound for use as a coating, represented by the following chemical formula 1, is provided:

[0014] <Chemical Formula 1>

[0015]

[0016] (In the above chemical formula 1,

[0017] X1 to X7 are each independently C, CR, or N, wherein each R is independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl. Adjacent Rs may or may not form a ring through mutual bonding.

[0018] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0019] L, L1, and L2 are each independently a directly bonded, substituted, or unsubstituted C6-C50 arylene or a C2-C50 heteroarylene.

[0020] Furthermore, in one embodiment of the present invention,

[0021] An organic light-emitting element containing a coating compound as described above is provided.

[0022] According to an embodiment of the present invention, a compound for a capping layer, such as an aromatic amine compound in the form of indoleazine or imidazopyridine, which contains one or more nitrogen (N) atoms in a specific position, can enhance the absorption wavelength in the ultraviolet region while having a wide band gap and high refractive index in the region where it is difficult to absorb visible light. This enables the creation of organic light-emitting elements with high color purity, high efficiency, and long lifespan when used as a capping layer for organic light-emitting elements.

[0023] Furthermore, the refractive index can be improved by optimizing the thin film arrangement between molecules.

[0024] Furthermore, the high glass transition temperature (Tg) and high dew point temperature (Td) prevent recrystallization between molecules and maintain the stability of the film when heat is generated during the driving process of organic light-emitting elements. It can also improve stability by protecting the element from the influence of external air and moisture, thereby improving external quantum efficiency and significantly improving service life.

[0025] Next, we will explain in detail the effects described above and the additional effects. Attached Figure Description

[0026] Figure 1 This is a schematic cross-sectional view of the layer structure of an organic light-emitting element according to an embodiment of the present invention.

[0027] Figure 2 This is a graph showing the measurement of absorption wavelengths in the range of 340nm to 460nm.

[0028] [Symbol Explanation]

[0029] 100: Substrate

[0030] 200: Hole injection layer

[0031] 300: Hole Transport Layer

[0032] 400: Emissive layer

[0033] 500: Electron transport layer

[0034] 600: Electron Injection Layer

[0035] 1000: Electrode 1

[0036] 2000: Second Electrode

[0037] 3000: Overlay Detailed Implementation

[0038] Before providing a detailed description of the invention, it should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the scope of the invention, which should be defined only by the scope of the appended claims. Unless otherwise expressly stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0039] Throughout this specification and the claims, unless otherwise expressly stated, the terms "comprise," "comprises," or "comprising" are used only to indicate that the mentioned object, step, or series of objects and steps are included, and do not preclude any other object, step, or series of objects or steps.

[0040] Throughout this specification and the claims, the term "aryl" refers to substances such as phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrene, triphenylene, and phenylenetriene. Benzyl, fluoranyl, benzo[a]fluorene, benzo[a]triphenylene, benzo[a] The term "heteroaryl" refers to C5-50 aromatic ring groups, including pyrrole, anthracene, piracene, and pyrene rings. "Heteroaryl" refers to groups such as pyrrole, pyrazinyl, pyridinyl, indole, isoyindole, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, quinolinyl, isoquinolinyl, quinoxalinyl, carbazolyl, phenanthridine, acridine, phenanthrolinyl, thiophene, and those composed of pyridine, pyrazine, pyrimidine, pyridazine, triazine, indole, quinoline, acridine, pyrrolidine, and diphenyl pyrrolidine rings. Alkyl ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, azole ring, A C2-50 aromatic ring comprising a heterocyclic group consisting of a diazole ring, a benzofuran ring, a thiazole ring, a thiadiazole ring, a benzothiophene ring, a benztriazole ring, an imidazole ring, a benzimazole ring, a pyran ring, or a dibenzofuran ring, including at least one heteroelement.

[0041] In addition, Ar in the chemical formula x (where x is an integer) unless otherwise explicitly defined, L represents a substituted or substituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, L x (where x is an integer) unless otherwise explicitly defined, R represents a directly bonded, substituted or unsubstituted C6–C50 arylene, or a substituted or unsubstituted C2–C50 heteroarylene, R x(where x is an integer) Unless otherwise explicitly defined, it means hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0042] Throughout this specification and the claims, the term "substituted or unsubstituted" may refer to a group consisting of deuterium, halogen, amino, cyano, nitrile, nitro, nitrosyl, aminosulfonyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylthioalkyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1 The substituted or unsubstituted group is selected from the group consisting of N-alkylamino (C12), N,N-dialkylamino (C2-C20), substituted or unsubstituted thiol (C1-C30), N-alkylaminosulfonyl (C1-C6), N,N-dialkylaminosulfonyl (C2-C12), silyl (C3-C30), cycloalkyl (C3-C20), heterocycloalkyl (C3-C20), aryl (C6-C50), and heteroaryl (C3-C50). Furthermore, throughout this application, unless otherwise expressly stated, the same symbols have the same meaning.

[0043] Furthermore, unless otherwise expressly stated to the contrary, various embodiments of the present invention may be combined with certain other embodiments. The embodiments of the present invention and their effects will now be described.

[0044] An organic light-emitting element according to an embodiment of the present invention may be an organic light-emitting element including a capping layer. Specifically, it may be an organic light-emitting element including a first electrode, a second electrode, one or more organic layers between the inner sides of the first electrode and the second electrode, and a capping layer disposed outside any one or more of the first electrode and the second electrode and containing the capping layer compound of the present invention.

[0045] As a specific example of the coating compound of the present invention, it may include the coating compound represented by the following chemical formula 1.

[0046] <Chemical Formula 1>

[0047]

[0048] In the above chemical formula 1,

[0049] X1 to X7 are each independently C, CR, or N, wherein each R is independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl. Adjacent Rs may or may not form a ring through mutual bonding.

[0050] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0051] L, L1, and L2 are each independently a directly bonded, substituted, or unsubstituted C6-C50 arylene or a C2-C50 heteroarylene.

[0052] In the above, the substituents used for substitution can be deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0053] Any one of X1 to X7 above is C, and L is directly associated with C.

[0054] The compounds of the present invention, represented by the above-described chemical formula 1, are aromatic amine compounds containing one or more nitrogen (N) atoms in the form of indoleazine or imidazopyridine, which must be located in a specific position. These compounds can enhance the absorption wavelength in the ultraviolet region while possessing a wide band gap and high refractive index, which are difficult to absorb visible light. This allows for the realization of organic light-emitting elements with high color purity, high efficiency, and long lifespan. Furthermore, by minimizing the volume characteristics of the aromatic amine's terminal portion, the intermolecular film arrangement can be optimized, thereby improving the refractive index. Moreover, the high glass transition temperature (Tg) and high dew point temperature (Td) prevent recrystallization between molecules and maintain the film's stability when heat is generated during the operation of the organic light-emitting element. Additionally, the stability can be improved by protecting the element from external air and moisture, thus achieving an organic light-emitting element with improved external quantum efficiency and significantly improved lifespan.

[0055] As a specific example compound for the capping layer of the present invention, the above-described chemical formula 1 may include a capping layer compound represented by the following chemical formula 2 or chemical formula 3.

[0056] <Chemical Formula 2>

[0057]

[0058] <Chemical Formula 3>

[0059]

[0060] In the above chemical formulas 2 and 3,

[0061] The definitions of X1 to X7, Ar2, L, L1 and L2 are the same as those in the above chemical formula 1.

[0062] Any one of X1 to X7 above is C, and L, L1 or L2 is directly bound to C.

[0063] The coating compound of the present invention, represented by the above chemical formula 2 or chemical formula 3, further contains two or three heterobicyclic rings compared with the above chemical formula 1, thereby achieving a higher refractive index and improving stability when exposed to external ultraviolet light by increasing the absorption wavelength in the ultraviolet region.

[0064] Furthermore, as a specific example compound for the coating layer of the present invention, the above-mentioned chemical formula 1 may include a coating layer compound represented by the following chemical formula 4.

[0065] <Chemical Formula 4>

[0066]

[0067] In the above chemical formula 4,

[0068] The definitions of X1 to X7, L1, L2, Ar1, and Ar2 are the same as those in Chemical Formula 1 above.

[0069] The definition of R1 is independently the same as the definition of R in the above chemical formula 1.

[0070] l is an integer from 0 to 5.

[0071] m are each an independent integer from 0 to 4.

[0072] Specifically, l can be an integer greater than or equal to 1.

[0073] Compared with the compound of the present invention represented by the above chemical formula 1, the heterobicyclic compound of the present invention, by directly binding or by binding to the amine core (N) through one or more phenylene groups, can minimize the absorption wavelength in the blue region and effectively improve the refractive index.

[0074] Furthermore, as a specific example compound for the coating layer of the present invention, the above-mentioned chemical formula 1 may include a coating layer compound represented by the following chemical formula 5.

[0075] <Chemical Formula 5>

[0076]

[0077] In the above chemical formula 5,

[0078] The definitions of X1 to X7, L1, L2, Ar1, and Ar2 are the same as those in Chemical Formula 1 above.

[0079] The definition of R1 is independently the same as the definition of R in the above chemical formula 1.

[0080] l is an integer from 0 to 5.

[0081] m are each an independent integer from 0 to 4.

[0082] Specifically, l can be an integer greater than or equal to 1.

[0083] Compared with the compound of the present invention represented by the above chemical formula 1, the heterobicyclic compound of the present invention, by directly binding or binding to the amine core (N) through one or more 1,4-phenylene oxides, can improve its stability when exposed to external ultraviolet light while having a high refractive index by increasing the absorption wavelength in the ultraviolet region.

[0084] Furthermore, in the aforementioned chemical formulas 1 to 5, L, L1, and L2 can each independently comprise phenylene, biphenylene, terphenylene, naphthylene, or combinations thereof. While not limited, any one or more of L, L1, and L2 can be 1,4-phenylene; specifically, L, L1, and L2 can all be composed of one or more 1,4-phenylene compounds. In the case described above, a high refractive index can be maintained, and the deposition temperature can be effectively improved.

[0085] Furthermore, in chemical formulas 1 to 5 above, X1 to X7 can each be independently C or CR. The definition of R is the same as in chemical formula 1 above. Specifically, CR can be CH. This reduces volume characteristics and minimizes long-wavelength absorption.

[0086] Furthermore, in the aforementioned chemical formulas 1 to 5, any one or more of X1 to X7 can be N. This allows for a higher refractive index and more effectively increases the absorption intensity in the ultraviolet region. Specifically, any one or more of X1 and X3 can be N. More specifically, X1 can be N.

[0087] Furthermore, in the aforementioned chemical formulas 1 to 5, X2 can be C. That is, by combining L, L1, or L2 at the X2 position of the heterobicyclic ring, the refractive index can be increased and the absorption intensity in the ultraviolet region can be enhanced.

[0088] Furthermore, in the aforementioned chemical formulas 1 to 5, Ar1 and Ar2 can each independently include phenyl, biphenyl, terphenyl, naphthyl, benzofuranyl, benzothiophene, dibenzofuranyl, dibenzothiophene, carbazole, phenanthrene, triphenylene, or combinations thereof. In the case described above, the volume characteristics can be minimized, and due to the excellent intermolecular thin film arrangement, a high refractive index can be achieved, which can also enhance the absorption in the ultraviolet region.

[0089] Furthermore, when the above chemical formula 1 is represented by the following chemical formula 6, any one or more of A, Ar1, and Ar2 may include any one of the following chemical formulas A-1 to A-26.

[0090] In the following chemical formulas A-1 to A-26, * indicates the binding site with L, L1, or L2.

[0091] <Chemical Formula 6>

[0092]

[0093]

[0094]

[0095] Furthermore, in the above chemical formulas 1 to 5, any one or more of –L1-Ar1 and –L2-Ar2 may include or include any one selected from chemical formulas B-1 to B-8.

[0096]

[0097] In the above chemical formulas B-1 to B-8, q is an integer from 0 to 3, and * represents the binding position to the amine nucleus (N).

[0098] By using structures comprising the aforementioned chemical formulas B-1 to B-8, high refractive index, stability of intermolecular film arrangement, enhanced absorption intensity in the ultraviolet region, and minimized absorption in the blue region can be achieved. Specifically, any one or more of –L1-Ar1 and –L2-Ar2 can be either chemical formula B-2 or B-8.

[0099] Furthermore, the aforementioned chemical formula 1 can be a coating compound represented by any of the following compounds. The following compounds are merely illustrative examples to illustrate the present invention and are not intended to limit the invention.

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140] An embodiment of the coating compound of the present invention described above can be synthesized by an amination reaction, the general synthetic reaction formula of which is shown below.

[0141]

[0142] (h = halogen atom)

[0143] In another embodiment of the present invention, an organic light-emitting element is provided, which is an organic light-emitting element including a cover layer, wherein the cover layer contains a cover layer compound as described above.

[0144] Next, an organic light-emitting element according to an embodiment of the present invention will be described in detail.

[0145] In one embodiment of the present invention, the organic light-emitting element may include a first electrode, a second electrode, and one or more organic layers between the first electrode and the second electrode, and a cover layer may be disposed on the outside of any one or more of the first electrode and the second electrode.

[0146] Specifically, the thickness of the aforementioned covering layer can be 100 to...

[0147] In addition, the refractive index of the aforementioned coating at 450nm can be above 2.20, specifically above 2.25, and more specifically above 2.30, while the ultraviolet absorption intensity at 380nm can be above 0.7, specifically above 0.8.

[0148] Specifically, the side of either the first or second electrode adjacent to the organic layer between the first and second electrodes is referred to as the inner side, and the side not adjacent to the organic layer is referred to as the outer side. That is, when the capping layer is disposed on the outer side of the first electrode, the first electrode will be located between the capping layer and the organic layer, and when the capping layer is disposed on the outer side of the second electrode, the second electrode will be located between the capping layer and the organic layer.

[0149] According to one embodiment of the present invention, the inner sides of the first electrode and the second electrode of the above-mentioned organic light-emitting element may be interposed with one or more layers of various organic materials, and a capping layer may be formed on the outer side of either the first electrode or the second electrode. That is, the capping layer may be formed simultaneously on the outer side of the first electrode and the outer side of the second electrode, or it may be formed only on the outer side of the first electrode or the outer side of the second electrode.

[0150] Furthermore, the aforementioned cover layer may include a cover layer compound according to the present invention, or may include only a cover layer compound according to the present invention, or may include two or more, or simultaneously include, known compounds.

[0151] Furthermore, the aforementioned organic layer may include, but is not limited to, the hole transport layer, the light-emitting layer, and the electron transport layer that typically constitute the light-emitting part.

[0152] Specifically, according to one embodiment of the present invention, an organic light-emitting element may include one or more organic layers constituting light-emitting portions such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) between the first electrode (anode) and the second electrode (cathode).

[0153] Figure 1 This is a cross-sectional view illustrating the structure of an organic light-emitting element according to an embodiment of the present invention. An organic light-emitting element according to one embodiment of the present invention can be configured as follows... Figure 1 The structure shown is manufactured.

[0154] like Figure 1As shown, the organic light-emitting element can be formed by stacking the substrate 100, the first 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 second electrode 2000, and the capping layer 3000 in sequence from bottom to top.

[0155] The substrate 100 described above can be any substrate commonly used in organic light-emitting elements, especially a transparent glass substrate or a flexible plastic substrate with excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

[0156] The first electrode 1000 described above is used as a hole injection electrode for injecting holes into an organic light-emitting element. To achieve hole injection, the first electrode 1000 is manufactured using a material with the lowest possible work function, and can be formed using transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene.

[0157] The aforementioned hole injection layer 200 can be formed by depositing hole injection layer material on the upper part of the first electrode 1000 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Blodgett (LB) method. When forming the hole injection layer 200 by vacuum deposition, the deposition conditions will vary depending on the compound used as the material for the hole injection layer 200, the desired structure of the hole injection layer 200, and its thermal properties. Typically, deposition temperatures ranging from 50 to 500°C and 10... -8 Up to 10 -3 The vacuum level of the Torr is 0.01 to... deposition rate per second and The layer thickness should be appropriately selected within the range of up to 5 μm. Furthermore, a charge generation layer can be deposited on the surface of the hole injection layer 200 as needed. Common materials can be used as the charge generation layer material, such as hexacyano-hexaazabenzophenanthrene (HATCN).

[0158] Next, the hole transport layer 300 can be formed by depositing hole transport layer material on top of the hole injection layer 200 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the hole transport layer 300 using the vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferable to select conditions within a range almost identical to those used for forming the hole injection layer 200. The hole transport layer 300 can be formed using known compounds. The hole transport layer 300 described above can be one or more layers, and although... Figure 1Although not illustrated, a light-emitting auxiliary layer can be added above the hole transport layer 300.

[0159] The aforementioned light-emitting layer 400 can be formed by depositing a light-emitting layer material on top of the hole transport layer 300 or the light-emitting auxiliary layer using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the light-emitting layer 400 using the aforementioned vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferable to select conditions within a range almost identical to those for forming the hole injection layer 200. Known compounds can be used as the main agent or dopant as the light-emitting layer material.

[0160] Furthermore, when phosphorescent dopants are used simultaneously in the light-emitting layer material, to prevent triplet excitons or holes from diffusing into the electron transport layer 500, a stacked hole-blocking material (HBL) can be added to the upper part of the light-emitting layer 400 by vacuum deposition or spin coating. The hole-blocking material used is not particularly limited and any known material can be selected. For example, it can be... Diazole derivatives or benzotriazole derivatives, o-diazaphenanthroline derivatives, or hole-blocking materials described in Japanese Patent Application Publication No. 11-329734 (A1), among which the most representative include Balq (bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum), phenanthroline compounds (e.g., UDC's BCP (bath copper spirit)), etc. The light-emitting layer 400 of the present invention, as described above, may include one or more blue light-emitting layers.

[0161] The electron transport layer 500 is formed on top of the light-emitting layer 400 and can be formed by methods such as vacuum deposition, spin coating, or casting. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally preferably selected within the same range as those for the formation of the hole injection layer 200.

[0162] The electron injection layer 600 can be formed by depositing electron injection layer material on top of the electron transport layer 500, and can be formed by methods such as vacuum deposition, spin coating, or casting.

[0163] The organic layers such as the hole injection layer 200, hole transport layer 300, light emission layer 400, and electron transport layer 500 of the aforementioned organic light-emitting element can be manufactured using known materials, but are not limited to them.

[0164] The second electrode 2000 described above is used as an electron injection electrode and can be formed on the upper part of the electron injection layer 600 by methods such as vacuum deposition or spin coating. Various metals can be used as the material for the second electrode 2000. Specific examples include materials such as aluminum, gold, silver, and magnesium, but it is not limited to these.

[0165] The organic light-emitting element of the present invention can not only use the organic light-emitting element as described above, which includes a capping layer 3000, a first 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 second electrode 2000, and a capping layer 3000, but can also use organic light-emitting elements with various structures, and can also add an intermediate layer including one or two layers as needed.

[0166] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted according to the desired degree, specifically from 1 to 1000 nm, or more specifically from 1 to 100 nm.

[0167] The aforementioned capping layer 3000 can be formed on the outer surfaces of the first electrode 1000 where the hole injection layer 200 is not formed. Furthermore, it can also be formed on the outer surfaces of the second electrode 2000 where the electron injection layer 600 is not formed, but is not limited thereto. The capping layer 3000 described above can be formed by a deposition process, and the thickness of the capping layer 3000 can be 100 mm to... More specifically, it could be 300 to By adjusting the thickness as described above, the problem of reduced transmittance of the cover layer 3000 can be prevented.

[0168] In addition, although Figure 1 Although not illustrated, according to one embodiment of the present invention, an organic layer for performing various functions may be additionally formed between the cover layer 3000 and the first electrode 1000 or between the cover layer 3000 and the second electrode 2000. Alternatively, an organic layer for performing various functions may also be additionally formed on the upper part (outer surface) of the cover layer 3000, but this is not a limitation.

[0169] 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 manufacturing examples and embodiments described below are merely illustrative of the present invention, and the scope of the present invention is not limited to the manufacturing examples and embodiments described below.

[0170] Manufacturing Example 1: Synthesis of Compound 53

[0171]

[0172] In a round-bottom flask, 3.0 g of 2-(4'-bromo-[1,1'-biphenyl]-4-yl)indolizine, 4.0 g of bis(4-(naphthalen-2-yl)phenyl)amine, 120 g of t-BuONa, 0.3 g of Pd2(dba)3, and 0.4 mL of (t-Bu)3P were dissolved in 110 mL of toluene and stirred under reflux. The reaction was confirmed by thin-layer chromatography (TLC), and the reaction was terminated after the addition of water. The organic layer was extracted with dichloromethane (MC) and recrystallized after filtration under reduced pressure to give 4.0 g of compound 53 (yield 68%).

[0173] m / z: 688.29 (100.0%), 689.29 (56.7%), 690.29 (15.9%), 691.30 (2.9%)

[0174] Manufacturing Example 2: Synthesis of Compound 161

[0175]

[0176] Compound 161 was synthesized using the same method as in Manufacturing Example 1, wherein 2-(4'-bromo-[1,1'-biphenyl]-4-yl)imidazo[1,2-a]pyridine was substituted for 2-(4'-bromo-[1,1'-biphenyl]-4-yl)indolizine. (Yield: 65%)

[0177] m / z: 689.28 (100.0%), 690.29 (55.6%), 691.29 (15.1%), 692.29 (2.8%), 690.28 (1.1%)

[0178] Manufacturing Example 3: Synthesis of Compound 168

[0179]

[0180] Compound 168 was synthesized using the same method as in Manufacturing Example 1, wherein 2-(4-bromophenyl)imidazo[1,2-a]pyridine and [1,1':4',1”:4”,1”'-quaterphenyl]-4-amine were used to replace 2-(4'-bromo-[1,1'-biphenyl]-4-yl)indolizine and bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 64%)

[0181] m / z: 705.29 (100.0%), 706.29 (55.9%), 707.30 (14.5%), 708.30 (2.5%), 707.29 (1.0%)

[0182] Manufacturing Example 4: Synthesis of Compound 170

[0183]

[0184] Compound 170 was synthesized using the same method as in Manufacturing Example 1, wherein 2-(4-bromophenyl)imidazo[1,2-a]pyridine and 4'-(naphthalen-2-yl)-[1,1'-biphenyl]-4-amine were used to replace 2-(4'-bromo-[1,1'-biphenyl]-4-yl)indolizine and bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 66%)

[0185] m / z: 679.27 (100.0%), 680.28 (52.3%), 681.28 (13.4%), 682.28 (2.4%), 680.27 (1.8%)

[0186] Manufacturing Example 5: Synthesis of Compound 178

[0187]

[0188] Compound 178 was synthesized using the same method as in Manufacturing Example 1, wherein 2-(4-bromophenyl)imidazo[1,2-a]pyridine and 4'-(imidazo[1,2-a]pyridin-2-yl)-[1,1'-biphenyl]-4-amine were used to replace 2-(4'-bromo-[1,1'-biphenyl]-4-yl)indolizine and bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 61%)

[0189] m / z: 669.26 (100.0%), 670.27 (49.0%), 671.27 (11.8%), 670.26 (2.6%), 672.27 (2.1%), 671.26 (1.3%) m / z: 711.21 (10 0.0%), 712.21 (54.5%), 713.21 (15.4%), 713.20 (9.1%), 714.20 (5.0%), 714.22 (2.5%), 712.20 (2.0%), 715.21 (1.4%)

[0190] Manufacturing of organic light-emitting elements

[0191] According to such Figure 1 The structure shown creates an organic light-emitting element. The organic light-emitting element is formed by stacking the following layers from bottom to top: substrate 100, anode (hole injection electrode 1000), hole injection layer 200, hole transport layer 300, light-emitting layer 400, electron transport layer 500, electron injection layer 600, cathode (electron injection electrode 2000), and capping layer 3000.

[0192] The compounds used in the organic layer located inside the electrode of the organic light-emitting element of the present invention are shown in Table 1 below.

[0193] Table 1

[0194]

[0195] Example 1

[0196] A hole injection layer is formed on top of an indium tin oxide (ITO) substrate having an Ag-containing reflective layer. HI01, HATCN and its role as a hole transport layer After HTO1, it is used as the light-emitting layer and doped with 3% BH01:BD01. The membrane. Next, a membrane is formed as the electron transport layer. ET01:Liq (1:1) was deposited afterward. An electron-injected layer is formed by LiF. Next, MgAg is deposited at a thickness of 15 nm, and then used as a capping layer above the cathode, with the compound manufactured in Manufacturing Example 1... The thickness of the deposition is then increased. Organic light-emitting elements are fabricated by encapsulating these elements in a glove box.

[0197] Examples 2 to 5

[0198] Organic light-emitting elements were manufactured by depositing a capping layer using the compounds manufactured in Manufacturing Examples 2 to 5, respectively, in the same manner as in Example 1 above.

[0199] Comparative Examples 1 to 3

[0200] Organic light-emitting elements were manufactured using the same method as in Example 1 above, wherein comparative compounds 1 (Ref. 1) to 3 (Ref. 3) shown in Table 2 below were deposited to form capping layers to produce organic light-emitting elements.

[0201] Table 2

[0202]

[0203] <Experimental Example 1> Performance Evaluation of Organic Light-Emitting Element

[0204] By injecting electrons and holes by applying a voltage to a Kiethley 2400 source measurement unit and measuring the brightness of the emitted light using a Konica Minolta spectroradiometer (CS-2000), the performance of the organic light-emitting elements of Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated under atmospheric pressure conditions, namely, the current density and brightness relative to the applied voltage. The results are shown in Table 3.

[0205] Table 3

[0206] Example 1 3.45 10 7.59 0.139 0.044 170 Example 2 3.45 10 7.70 0.140 0.044 178 Example 3 3.46 10 7.74 0.140 0.044 180 Example 4 3.45 10 7.75 0.140 0.043 182 Example 5 3.46 10 7.78 0.140 0.044 185 Comparative Example 1 3.46 10 6.40 0.131 0.056 81 Comparative Example 2 3.46 10 6.65 0.130 0.052 98 Comparative Example 3 3.46 10 6.82 0.133 0.050 103

[0207] By comparing the embodiments of the present invention, it can be found that, compared with Comparative Example 1, the present invention can minimize the volume characteristics and have a high refractive index by combining a heterobicyclic ring such as imidazopyridine with an aromatic amine, while also increasing the absorption wavelength in the ultraviolet region and effectively improving the efficiency and lifetime of the organic light-emitting element with a higher Tg.

[0208] Furthermore, compared to Comparative Examples 2 and 3, the present invention can minimize the volume characteristics of the core and improve the polarizability of the molecule by including a heterobicycle with nitrogen (N) at a specific position. Moreover, it can form a stable thin film while improving the refractive index through excellent thin film arrangement, thereby realizing an organic light-emitting element with low driving voltage, high color purity, high efficiency and long service life.

[0209] <Experimental Example 2> Evaluation of Refractive Index

[0210] Using compounds 161 and 170 of the present invention, prepared through the above steps, and comparative compounds 1 (Ref. 1) to 3 (Ref. 3) of Table 2 above, a 30 nm thick deposition film was fabricated on a silicon substrate using a vacuum deposition apparatus. The refractive index at 450 nm was then measured using an ellipsometry (JAWoollam Co. Inc., M-2000X). The results are shown in Table 4 below.

[0211] Table 4

[0212]

[0213] As shown in Table 4 above, it can be confirmed that compounds 161 and 170 of the present invention have a refractive index of 2.20 or higher, more specifically 2.25 or higher, and more specifically 2.30 or higher at 450 nm.

[0214] <Experimental Example 3> Evaluation of Absorption Intensity in the Ultraviolet Region

[0215] Using compounds 161 and 170 of the present invention, prepared through the above steps, and comparative compounds 1 (Ref. 1) and 2 (Ref. 2) from Table 2, a 30 nm thick deposition film was fabricated on a silicon substrate using a vacuum deposition apparatus. The absorption wavelengths in the range of 340 nm to 460 nm were then measured using an ellipsometer (JAWoollam Co. Inc., M-2000X). The results are as follows: Figure 2 As shown.

[0216] At a reference ultraviolet absorption region of 380 nm, the absorption intensity of compounds 161 and 170 of the present invention is 0.7 or higher, specifically 0.8 or higher, which confirms that the absorption intensity is increased by more than 50%, specifically more than 60%, compared with comparative compound 1 (Ref. 1).

Claims

1. A compound for a capping layer represented by the following chemical formula 1: Chemical Formula 1 In the above chemical formula 1, X1 is either CR or N. X2 is C. X3 to X7 are CR. Each of the above Rs can be either hydrogen or deuterium. Ar1 is a triphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. Ar2 can be phenyl, biphenyl, terphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. L, L1, and L2 are each independently a direct-linked, phenylene, biphenylene, or terphenylene. Ar1, Ar2, L, L1, and L2 are each independently unsubstituted or deuterated.

2. A compound for a capping layer represented by the following chemical formula 4: Chemical Formula 4 In the above chemical formula 4, X1 is either CR or N. X2 is C. X3 to X7 are CR. Each of the above Rs can be either hydrogen or deuterium. Ar1 is a triphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. Ar2 can be phenyl, biphenyl, terphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. L1 and L2 are each independently a direct-linked, phenylene, biphenylene, or terphenylene. Ar1, Ar2, L1, and L2 are each independently unsubstituted or deuterated. R1 can be either hydrogen or deuterium independently. l is an integer from 0 to 5. m are each an independent integer from 0 to 4.

3. A compound for a capping layer represented by the following chemical formula 5: Chemical formula 5 In the above chemical formula 5, X1 is either CR or N. X2 is C. X3 to X7 are CR. Each of the above Rs can be either hydrogen or deuterium. Ar1 is a triphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. Ar2 can be phenyl, biphenyl, terphenyl, naphthyl, or... X1 to X7 are each independently identical to the definitions above. L1 and L2 are each independently a direct-linked, phenylene, biphenylene, or terphenylene. Ar1, Ar2, L1, and L2 are each independently unsubstituted or deuterated. R1 can be either hydrogen or deuterium independently. l is an integer from 0 to 5. m are each an independent integer from 0 to 4.

4. The compound for a coating layer according to claim 1, characterized in that: X1 above is CR, R is defined in the same way as in the above chemical formula 1.

5. The compound for a coating layer according to claim 4, characterized in that: In the above CR, R stands for hydrogen.

6. The compound for a coating layer according to claim 1, characterized in that: X1 above is N.

7. The compound for a coating layer according to claim 1, characterized in that: Each is independently one of the following chemical formulas: A-1 and A-10: 。 8. The compound for a coating layer according to claim 1, characterized in that: Any one or more of –L1-Ar1 and –L2-Ar2 above are selected from the following chemical formulas B-1 and B-2: In the above chemical formulas B-1 and B-2, Each q is an integer from 0 to 3.

9. The compound for a coating layer according to claim 8, characterized in that: Any one or more of –L1-Ar1 and –L2-Ar2 is the above chemical formula B-2.

10. The compound for a coating layer according to claim 1, characterized in that: Chemical formula 1 is any one of the following compounds: 。 11. An organic light-emitting element, characterized in that, include: A capping layer comprising a capping compound according to any one of claims 1 to 10.

12. The organic light-emitting element according to claim 11, characterized in that: The aforementioned organic light-emitting element includes: The first electrode and the second electrode; and, One or more organic layers are located inside the first electrode and the second electrode. The aforementioned covering layer is disposed on the outside of any one or more of the first electrode and the second electrode.

13. The organic light-emitting element according to claim 11, characterized in that: The thickness of the aforementioned covering layer is 100 to 2000 Å.

14. The organic light-emitting element according to claim 11, characterized in that: The aforementioned coating has a refractive index of 2.20 or higher at a wavelength of 450 nm.

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