Novel compound for a cover layer and organic light emitting element comprising the same

Abstract

The present application provides a compound represented by the following Chemical Formula 1 and an organic light emitting element including the same: <Chemical Formula 1>

Description

Technical Field

[0001] This invention relates to a novel compound for a coating layer and an organic light-emitting element comprising the 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] Furthermore, the luminescent materials can be classified according to their luminescence mechanism into fluorescent materials originating from a singlet excited state of electrons and phosphorescent materials originating from a triplet excited state of electrons, and 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 structured with an anode formed on the top of a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode sequentially formed 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. The holes and electrons will recombine in the light-emitting layer to generate excitons.

[0007] Light is generated during the transition of excitons from the excited state to the ground state. The efficiency of organic light-emitting elements 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 organic compounds with high refractive index and thin film stability that can improve external luminous efficiency. Summary of the Invention

[0009] Therefore, the purpose of this invention is to provide an organic light-emitting element that can improve the absorption wavelength in the ultraviolet region while ensuring a wide band gap in the region where visible light is difficult to absorb and maintaining a high refractive index, thereby achieving high color purity, high efficiency and long service life.

[0010] Furthermore, the present invention aims to provide an organic light-emitting element that can improve the thin film arrangement between molecules by increasing the polarizability of molecules and thereby improve the refractive index, and can also improve the stability to external air and / or moisture. Moreover, it can prevent recrystallization between molecules by using a higher glass transition temperature (Tg) and decomposition temperature (Td) and maintain the stability of the thin film when heat is generated during the device driving process, thereby further improving the external quantum efficiency and lifespan.

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

[0012] As a means of solving the problems mentioned above,

[0013] An embodiment of the present invention provides a compound for a coating layer represented by the following chemical formula 1:

[0014] <Chemical Formula 1>

[0015]

[0016] <Chemical Formula 1-1>

[0017]

[0018] In the chemical formula 1,

[0019] A represents chemical formula 1-1.

[0020] X1 to X8 are each independently C, CR, or N, and more than one of them is N.

[0021] Ar1 to Ar3 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0022] R can be 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 C3-C30 silyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl. Multiple adjacent Rs may or may not form a ring by combining with each other.

[0023] L and L1 are each independently a substituted or unsubstituted C6-C50 arylene or a substituted or unsubstituted C2-C50 heteroarylene.

[0024] Furthermore, as an embodiment of the present invention,

[0025] An organic light-emitting element containing a coating compound as described above is provided.

[0026] The coating compound according to the present invention is a compound containing two amine groups, which are fused bicyclic heteroaryl groups containing one or more N, as the parent core, and can achieve high color purity by maintaining a wide band gap in the region where visible light is difficult to absorb.

[0027] Furthermore, because the intermolecular film arrangement of the capping compound according to the present invention is excellent, the layer containing the capping compound can simultaneously improve both the refractive index and the absorption wavelength in the ultraviolet region. Therefore, when the capping compound is used as a capping layer for an organic light-emitting element, it can improve the external quantum efficiency of the organic light-emitting element and enhance its stability against ultraviolet light.

[0028] Furthermore, because the compound for the capping layer according to the present invention has a high glass transition temperature (Tg) and decomposition temperature (Td), it can prevent recrystallization between molecules and maintain the stability of the film when heat is generated during the device driving process.

[0029] Next, we will explain in detail the effects described above and the additional effects. Attached Figure Description

[0030] Figure 1 This is a schematic cross-sectional view illustrating the structure of an organic light-emitting element according to an embodiment of the present invention.

[0031] Figure 2 This is a graph showing the absorption intensity of compounds 11 and 54 used in the coating layer according to an embodiment of the present invention, compared with comparative compounds 1 and 2, in the range of 340 nm to 460 nm.

[0032] [Symbol Explanation]

[0033] 100: Substrate

[0034] 200: Hole injection layer

[0035] 300: Hole Transport Layer

[0036] 400: Emissive layer

[0037] 500: Electron transport layer

[0038] 600: Electron Injection Layer

[0039] 1000: Electrode 1 (Anode)

[0040] 2000: Second electrode (cathode)

[0041] 3000: Overlay Detailed Implementation

[0042] 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.

[0043] 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.

[0044] Throughout this specification and the claims, the term "aryl" may refer to substances including phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrene, triphenylene, phenylene, etc. Benzyl, fluoranyl, benzo[a]fluorene, benzo[a]triphenylene, benzo[a] "C5-50 aromatic ring groups" include pyrrole, anthracene, piracene, and pyrene rings, while "heteroaryl" refers to those containing pyrrole, pyrazinyl, pyridinyl, indole, isoindole, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, quinolinyl, isoquinolinyl, quinoxalinyl, carbazolyl, phenanthridine, acridine, phenanthridine, thiophene, and those composed of pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, triazine rings, indole rings, quinoline rings, acridine rings, pyrrolidine rings, and diphenyl rings. Alkyl ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, azole ring, A C2-50 aromatic ring containing one or more heterocyclic elements, consisting of a heterocyclic group composed of diazole ring, benzofuran ring, thiazole ring, thiadiazole ring, benzothiophene ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, dibenzofuran ring, etc.

[0045] 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.

[0046] Throughout this specification and the claims, the term "substituted or unsubstituted" means derived from 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-C12 N The designation may include any one or more groups selected from the group consisting of alkylamino, C2-C20 N,N-dialkylamino, substituted or unsubstituted C1-C30 mercapto, C1-C6 N-alkylaminosulfonyl, C2-C12 N,N-dialkylaminosulfonyl, C3-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C2-C50 heteroaryl, but is not specifically limited thereto. Furthermore, throughout this specification, unless otherwise expressly stated, the same symbols have the same meaning.

[0047] 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.

[0048] The present invention will now be described in detail.

[0049] The compound for the coating layer according to the present invention can be represented by the following chemical formula 1:

[0050] <Chemical Formula 1>

[0051]

[0052] <Chemical Formula 1-1>

[0053]

[0054] In the chemical formula 1,

[0055] A represents chemical formula 1-1.

[0056] X1 to X8 are each independently C, CR, or N, and more than one of them is N.

[0057] Ar1 to Ar3 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0058] R can be 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 C3-C30 silyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl. Multiple adjacent Rs may or may not form a ring by combining with each other.

[0059] L and L1 are each independently a substituted or unsubstituted C6-C50 arylene or a substituted or unsubstituted C2-C50 heteroarylene.

[0060] Specifically, in the chemical formula 1-1, any one of X1 to X4 can be C, and in the case described above, the C is combined with L1.

[0061] The coating compound represented by the aforementioned chemical formula 1 is a compound whose core structure contains two amine groups bonded with a fused bicyclic heteroaryl group containing one or more N (chemical formula 1-1), which can achieve high color purity by maintaining a wide band gap in the region where visible light is difficult to absorb.

[0062] Furthermore, due to the excellent intermolecular film arrangement, both the refractive index and the absorption wavelength in the ultraviolet region can be improved simultaneously. Therefore, when the coating compound is used as a coating layer for an organic light-emitting element, the external quantum efficiency of the organic light-emitting element and its stability against ultraviolet light can be improved.

[0063] Furthermore, due to its high glass transition temperature (Tg) and decomposition temperature (Td), it can prevent recrystallization between molecules and maintain the stability of the film when heat is generated during device operation.

[0064] Specifically, the chemical formula 1 can be represented by the following chemical formula 2 or chemical formula 3:

[0065] <Chemical Formula 2>

[0066]

[0067] <Chemical Formula 3>

[0068]

[0069] In chemical formulas 2 and 3,

[0070] The definitions of A, Ar1 to Ar3, L, and L1 are the same as those in Chemical Formula 1.

[0071] L2 is a substituted or unsubstituted C6-C41 arylene, or a substituted or unsubstituted C2-C41 heteroarylene.

[0072] The number of carbons in L2 and the A that binds to L2 satisfies the range of carbon numbers defined in Ar1 or Ar2.

[0073] The coating compound represented by the chemical formula 2 or chemical formula 3 is a compound in which two or more A groups represented by chemical formula 1-1 are connected to two amine groups by a linker (L1 or L2), and the effect of increasing the refractive index can be achieved by including two or more N-containing fused bicyclic rings.

[0074] Specifically, the coating compound represented by the chemical formula 2 is a compound in which two amino groups in the core structure are respectively combined with A, which can achieve the effect of minimizing the absorption in the visible light region while increasing the absorption in the ultraviolet light region.

[0075] Furthermore, the coating compound represented by the aforementioned chemical formula 3 is a compound in which at least one of the two amine groups contained in the core structure is simultaneously bonded to both A groups, and the refractive index can be improved more effectively by minimizing the volume characteristics of one side amine group.

[0076] More specifically, the chemical formula 1 can be represented by the following chemical formula 4 or chemical formula 5:

[0077] <Chemical Formula 4>

[0078]

[0079] <Chemical Formula 5>

[0080]

[0081] In chemical formulas 4 and 5,

[0082] The definitions of X1, X2, X4 to X8, Ar1 to Ar3, L, and L1 are the same as those in Formula 1 (wherein, the number of carbons of X1, X2, X4 to X8 of the bicyclic fused ring bound to L2 satisfies the range of carbon numbers defined in Ar1 or Ar2).

[0083] L2 is a substituted or unsubstituted C6-C41 arylene, or a substituted or unsubstituted C2-C41 heteroarylene.

[0084] The X1, X2, X4, X5, X6, X7, or X8 may be the same as or different from each other.

[0085] The coating compound represented by the aforementioned chemical formula 4 or chemical formula 5 is a compound in which two or more A groups represented by chemical formula 1-1 are connected to specific positions of two amino groups contained in the parent core structure via linking groups (L1 or L2), specifically to the X3 position of chemical formula 1-1, thereby significantly improving the absorption intensity in the ultraviolet region while having a high refractive index.

[0086] Specifically, the coating compound represented by the chemical formula 4 is a compound in which the X3 position of chemical formula 1-1 is bonded to the linking groups L1 and L2. It can minimize unnecessary absorption in the visible light region and enhance absorption in the ultraviolet region by having a structure in which chemical formula 1-1 is bonded to two amine groups respectively. It can also have a higher refractive index by being bonded to the X3 position.

[0087] Furthermore, the capping compound represented by the chemical formula 5 is a compound in which the X3 position of chemical formula 1-1 is bonded to the linking groups L1 and L2. It can minimize the volume characteristics of one side of the amine group by having a structure in which chemical formula 1-1 is simultaneously substituted to either of the two amine groups, and can also have a higher refractive index by being bonded to the X3 position.

[0088] Furthermore, in the chemical formula 1-1, only one of X1 to X8 can be N. Specifically, one of the chemical formulas X1 to X4 can be N, while the remaining X1 to X8 can all be CR. In the case described above, because of the high intramolecular polarizability, an improvement in refractive index and ultraviolet absorption intensity can be achieved.

[0089] As an example, the chemical formula 1-1 may include any one of the structures represented by structures A-1 to A-7, specifically structure A-1 or A-2:

[0090]

[0091] In structures A-1 to A-7,

[0092] The definition of R is the same as that in Chemical Formula 1.

[0093] * indicates the position where the amino group is bound via the linker L1.

[0094] As described above, the coating compound of the present invention, which contains only one of the N-type fused bicyclic rings of the X1 to X8 of the chemical formula 1-1, can significantly reduce electron-withdrawing function, thereby minimizing unwanted light absorption in the visible light region.

[0095] Furthermore, in the chemical formula 1-1, R can be hydrogen or phenyl. Under the conditions described above, the volume characteristics of chemical formula 1-1 can be minimized, and the refractive index of the compound can be effectively increased even with a smaller molecular weight, while also improving the thermal stability during deposition.

[0096] Furthermore, in any one of the chemical formulas 1 to 5,

[0097] L can contain phenylene, biphenylene, terphenylene, naphthyl, fluorene, pyridylene, diphenylfuranyl, dibenzothiopheneyl, carbazoleyl, or combinations thereof. By including the substituents described above in L, the π-conjugation of the linking group can be minimized, thus increasing the refractive index while minimizing unwanted absorption in the visible light region.

[0098] Specifically, in any one of the chemical formulas 1 to 5, L may include any one of the structures represented by structures B-1 to B-13.

[0099]

[0100] When the linker L comprises any one of structures B-1 to B-13, the two amines can be linearly linked while minimizing volume characteristics, thereby improving ultraviolet absorption intensity. Furthermore, due to its high refractive index, it can effectively improve device efficiency and lifespan. Specifically, the linker L can be B-2 or B-3.

[0101] Furthermore, structures B-1 to B-7 may contain ortho (1,2-phenylene), meta (1,3-phenylene), or para (1,4-phenylene) combinations, specifically para (1,4-phenylene), and more specifically, para (1,4-phenylene) alone.

[0102] Furthermore, in any of the chemical formulas 1 to 5, L1 and L2 may each independently contain phenylene, biphenylene, terphenylene, naphthylene, or combinations thereof. This minimizes the π-conjugation of the linking group, thus increasing the refractive index while minimizing absorption in the visible light region.

[0103] Specifically, L1 and L2 can be used independently. This indicates that l can be an integer from 1 to 3, specifically 1 or 2.

[0104] More specifically, L1 and L2 can each be independently configured... express.

[0105] By including more than one para-bonded 1,4-phenylene in L1 and L2, absorption in the visible light region can be minimized, while simultaneously increasing the refractive index and absorption intensity in the ultraviolet region.

[0106] Furthermore, in any one of the chemical formulas 1 to 5,

[0107] Ar1 to Ar3 can each independently contain phenyl, biphenyl, terphenyl, naphthyl, pyridyl, or combinations thereof, and can be substituted or unsubstituted with halogen, nitrile, C1-C6 alkyl, C1-C6 alkoxy, C1-C30 mercapto, cyano, or C6-C44 aryl (wherein, in the case of substitution, the carbon number range defined in Ar1 to Ar3 is satisfied). In the cases described above, the volume characteristics of the compound can be minimized, thereby improving intermolecular thin-film alignment, increasing the refractive index, and minimizing unwanted light absorption in the visible light region.

[0108] The following compounds are specific examples of compounds according to the present invention. These examples are merely illustrative and are not intended to limit the invention.

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130] One embodiment of the compound of the present invention can be synthesized by an amination reaction, the general synthetic reaction formula of which is shown below.

[0131]

[0132] In another embodiment of the invention, an organic light-emitting element is provided in which the cover layer contains the cover layer compound according to the invention as described above.

[0133] The organic light-emitting element according to the present invention will now be described in more detail.

[0134] 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 and a capping layer between the first electrode and the second electrode, wherein the capping layer may be disposed outside any one or more of the first electrode and the second electrode.

[0135] Specifically, the side of the first or second electrode adjacent to the organic layer between the first and second electrodes is called the inner side, and the side not adjacent to the organic layer is called 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.

[0136] Furthermore, in one embodiment of the present invention, the inner sides of the first electrode and the second electrode of the organic light-emitting element may be interposed with one or more layers of various organic materials, while 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.

[0137] At this time, the capping layer may contain a capping compound according to the present invention, may contain only a capping compound according to the present invention, or may contain two or more known compounds simultaneously.

[0138] Furthermore, the refractive index of the coating layer at a wavelength of 450nm can be 2.20 or higher, specifically 2.25 or higher, more specifically 2.30 or higher, and the ultraviolet absorption intensity at a wavelength of 380nm can be 0.7 or higher, specifically 0.8 or higher or 0.9 or higher.

[0139] Furthermore, the organic layer may include a hole transport layer, a light-emitting layer, and an electron transport layer that typically constitute the light-emitting part, but is not limited to these.

[0140] 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).

[0141] 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.

[0142] like Figure 1As shown, the organic light-emitting element can be a structure in which a substrate 100, 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 are stacked sequentially from bottom to top.

[0143] The substrate 100 can be a 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 processing and water resistance.

[0144] Furthermore, the first electrode 1000 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.

[0145] Meanwhile, the hole injection layer 200 can be formed by depositing the 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 method. When forming the hole injection layer 200 by vacuum deposition, the deposition conditions will vary depending on the compound used as the material of the hole injection layer 200, the desired structure of the hole injection layer 200, and its thermal properties. Typically, deposition temperatures of 50–500°C and 10… -8 Up to 10 -3 The vacuum level of the Torr is 0.01 to... The deposition rate 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).

[0146] Furthermore, 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 by 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 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.

[0147] Simultaneously, the 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 by vacuum deposition, the deposition conditions will vary depending on the compound used, but are generally preferably selected within a range of conditions almost identical to those for forming the hole injection layer 200. Known compounds can be used as the light-emitting layer material, either as the main agent or dopant.

[0148] 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 using vacuum deposition or spin coating. The hole-blocking material used is not particularly limited; any known material can be used. 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), etc. The light-emitting layer 400 of the present invention, as described above, may contain one or more blue light-emitting layers.

[0149] Furthermore, 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.

[0150] Furthermore, the electron injection layer 600 can be formed by depositing electron injection layer material on the upper part of the electron transport layer 500, and can be formed by methods such as vacuum deposition, spin coating, casting, etc.

[0151] Meanwhile, the second electrode 2000 serves 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 substances such as aluminum, gold, silver, and magnesium, but it is not limited to these.

[0152] The organic light-emitting element of the present invention can not only use the organic light-emitting element containing the capping layer 3000, 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 as described above, but can also use organic light-emitting elements with various structures, and can also add an intermediate layer containing one or two layers as needed.

[0153] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted according to the desired degree, specifically from 10 to 1000 nm, and more specifically from 20 to 150 nm.

[0154] The covering layer 3000, as Figure 1 As shown, the hole injection layer 200 may be formed on the outer side of the first electrode 1000 where no hole injection layer 200 is formed. Similarly, the electron injection layer 600 may be formed on the outer side of the second electrode 2000 where no electron injection layer 600 is formed, but this is not a limitation. 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.

[0155] 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.

[0156] Next, the present invention will be described in more detail through examples of the synthesis of compounds according to an embodiment of the present invention and examples of organic light-emitting elements. The following synthesis examples and embodiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

[0157] <Synthetic Example 1> Synthesis of Compound 11

[0158]

[0159] 80 mL of toluene was added to a round-bottom flask, and 2.0 g of 3-(4-bromophenyl)isoquinoline, 2.4 g of N4,N4'-diphenyl-[1,1'-biphenyl]-4,4'-diamine, 1.0 g of t-BuONa, 0.3 g of Pd2(dba)3, and 0.3 mL of (t-Bu)3P were dissolved in the solution before reflux and stirring. The extent of 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), filtered under reduced pressure, and recrystallized to give 3.5 g of compound 11 (yield 67%).

[0160] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0161] <Synthetic Example 2> Synthesis of Compound 47

[0162]

[0163] The same procedure as in Synthesis Example 1 was followed, in which compound 47 was synthesized by replacing 3-(4-bromophenyl)quinoline with 3-(4-bromophenyl)isoquinoline (64% yield).

[0164] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0165] <Synthetic Example 3> Synthesis of Compound 54

[0166]

[0167] Compound 54 was synthesized in 60% yield by means of 3-(4-bromophenyl)quinoline and N4,N4”-diphenyl-[1,1':4',1”-terphenyl]-4,4”-diamine instead of 3-(4-bromophenyl)isoquinoline and N4,N4’-diphenyl-[1,1':4',1”-terphenyl]-4,4”-diamine.

[0168] m / z: 818.34 (100.0%), 819.34 (66.4%), 820.35 (21.0%), 821.35 (4.4%)

[0169] <Synthetic Example 4> Synthesis of Compound 56

[0170]

[0171] 120 mL of toluene was added to a round-bottom flask, and 3.0 g of 4'-bromo-N,N-diphenyl-[1,1'-biphenyl]-4-amine, 3.2 g of bis(4-(quinolin-3-yl)phenyl)amine, 1.1 g of t-BuONa, 0.3 g of Pd2(dba)3, and 0.3 mL of (t-Bu)3P were dissolved in the solution before reflux and stirring. The extent of 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), filtered under reduced pressure, and recrystallized to obtain 3.4 g of compound 56 (yield 61%).

[0172] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0173] <Synthetic Example 5> Synthesis of Compound 119

[0174]

[0175] The same procedure as in Synthesis Example 1 was followed, in which compound 119 was synthesized by replacing 3-(4-bromophenyl)isoquinoline with 6-(4-bromophenyl)isoquinoline (6-(4-bromophenyl)isoquinoline) (yield 68%).

[0176] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0177] <Synthetic Example 6> Synthesis of Compound 83

[0178]

[0179] The same procedure as in Synthesis Example 1 was followed, in which compound 83 was synthesized by replacing 3-(4-bromophenyl)quinoline with 6-(4-bromophenyl)quinoline (6-(4-bromophenyl)quinoline) (6-(4-bromophenyl)iso ...quinoline) (6-(4-bromophenyl)isoquinoline)

[0180] m / z: 742.3096 (100.0%), 743.3130 (58.4%), 744.3164 (16.7%), 745.3197 (3.1%), 743.3067 (1.5%)

[0181] <Synthetic Example 7> Synthesis of Compound 227

[0182]

[0183] The same procedure as in Synthesis Example 1 was followed, in which compound 227 was synthesized by replacing 3-(4-bromophenyl)quinoline with 2-(4-bromophenyl)quinoline (62% yield).

[0184] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0185] Manufacturing of organic light-emitting elements

[0186] Figure 1 This is a schematic diagram illustrating the structure of a typical organic light-emitting element, used as an example of the present invention. Figure 1Based on the illustrated organic light-emitting element structure, a charge generation layer (not shown) is added between the hole injection layer 200 and the hole transport layer 300, and an electron injection layer (not shown) is added between the electron transport layer 500 and the cathode 2000. Specifically, the manufactured organic light-emitting element is formed by stacking the following layers from bottom to top in the following order: anode (hole injection electrode 1000) / hole injection layer 200 / charge generation layer (not shown) / hole transport layer 300 / light-emitting layer 400 / electron transport layer 500 / electron injection layer 600 / cathode (electron injection electrode 2000) / capping layer 3000.

[0187] When manufacturing organic light-emitting elements, the substrate 10 can be a transparent glass substrate or a flexible plastic substrate.

[0188] The hole injection electrode 1000 is used as an anode for injecting holes in an organic light-emitting element. To achieve hole injection, a material with the lowest possible work function is used, and transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene can be used to form it.

[0189] The materials shown in Table 1 below are used in the hole injection layer 200, charge generation layer, hole transport layer 300, light emission layer 400, electron transport layer 500, and electron injection layer 600.

[0190] Furthermore, a cathode 2000 for injecting electrons is formed on the upper side of the electron injection layer 600. Various metals can be used as the cathode. Specific examples include materials such as aluminum, gold, and silver.

[0191] Table 1

[0192]

[0193] <Example 1>

[0194] An indium tin oxide (ITO) substrate with a silver (Ag) reflective layer was cleaned using ultrasonic waves with distilled water. After washing with distilled water, ultrasonic cleaning was performed using solvents such as isopropanol, acetone, and methanol, followed by drying. Next, a hole injection layer was formed on the ITO substrate using a thermal evaporator. HI01, as a charge generation layer HATCN and its role as a hole transport layer Next, in the BH01 body, dopant BD01 is doped at 3% by weight to form a film. The light-emitting layer is then formed. Next, a film is prepared using a mixture of ET01 and Liq (1:1, wt. / wt.). The electron transport layer is then formed using LiF deposition. After an electron injection layer of a certain thickness, a 15 nm cathode is formed using MgAg deposition. A capping layer is then deposited on top of the cathode to form... The thickness of the compound was obtained by synthesis example 1. An organic light-emitting element was fabricated by encapsulating the element in a glove box.

[0195] Example 2 to Example 7

[0196] Organic light-emitting elements were manufactured by means of the same method as in Example 1, and organic light-emitting elements were manufactured by depositing a capping layer using the compounds produced by Synthesis Examples 2 to 7 respectively.

[0197] Comparative Example 1 and Comparative Example 2

[0198] Organic light-emitting elements were fabricated by depositing capping layers using comparative compound 1 and comparative compound 2 as shown in Table 2 below, in accordance with the same method as in Example 1.

[0199] Table 2

[0200]

[0201] <Experimental Example 1> Performance Evaluation of Organic Light-Emitting Element

[0202] 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 7 and Comparative Examples 1 to 2 was evaluated under atmospheric pressure conditions, namely, the current density and brightness relative to the applied voltage. The results are shown in Table 3.

[0203] Table 3

[0204] Example 1 3.65 10 7.65 0.139 0.045 175 Example 2 3.65 10 7.63 0.140 0.044 170 Example 3 3.64 10 7.69 0.140 0.044 172 Example 4 3.65 10 7.65 0.139 0.045 174 Example 5 3.65 10 7.59 0.139 0.045 169 Example 6 3.66 10 7.46 0.139 0.047 152 Example 7 3.65 10 7.60 0.139 0.045 169 Comparative Example 1 3.67 10 6.82 0.130 0.061 83 Comparative Example 2 3.66 10 6.69 0.132 0.054 111

[0205] By comparing the embodiments of the present invention, it can be found that the organic light-emitting elements of the embodiments can achieve a lower driving voltage, and their luminous efficiency and lifespan are also significantly improved.

[0206] Specifically, according to embodiments of the present invention, the organic light-emitting element contains a compound of chemical formula 1, such as quinoline, which has a fused bicyclic heteroaryl group that is bonded to the parent nucleus (i.e., two amine groups) through a non-directly bonded linker in the capping layer. This can improve the molecular fractionation rate, as well as the refractive index and the absorption wavelength in the ultraviolet region, thereby effectively improving the efficiency and lifespan of the organic light-emitting element.

[0207] Furthermore, the compound of Formula 1 can be stably formed into a thin film by forming a higher glass transition temperature (Tg). Therefore, the organic light-emitting element of the embodiment in which it is included in the capping layer has higher color purity and better effect on improving the efficiency and lifespan of the element compared with the organic light-emitting elements of Comparative Example 1 and Comparative Example 2.

[0208] <Experimental Example 2> Refractive Index Assessment

[0209] Using the compounds 1 (compound 11), 2 (compound 47), and 4 (compound 56) used in forming the capping layer in Examples 1, 2, and 4, respectively, and the comparative compounds 1 and 2 used in Comparative Examples 1 and 2, a 30 nm thick deposition film was fabricated on a silicon substrate using a vacuum deposition apparatus. The refractive index at a wavelength of 450 nm was then measured using an ellipsometer (JAWoollam Co., Inc., M-2000X). The results are shown in Table 4 below.

[0210] Table 4

[0211] Refractive index, n 2.01 2.07 2.30 2.28 2.30

[0212] As shown in Table 4 above, it can be confirmed that the refractive index of the compounds according to the present invention can exhibit a high refractive index of 2.2 or higher, specifically 2.25 or higher, and up to 2.30 or higher. As described above, because the compounds according to the present invention can exhibit a high refractive index, organic light-emitting elements with significantly improved external quantum efficiency and lifespan can be achieved when applied to a capping layer.

[0213] <Experimental Example 3> Evaluation of Ultraviolet Absorption Intensity

[0214] Using the compounds 11 (synthetic example 1) and 54 (synthetic example 3) used in forming the capping layer in Examples 1 and 3, respectively, and the comparative compounds 1 and 2 used in Comparative Examples 1 and 2, a 30 nm thick deposition film was fabricated on a silicon substrate using a vacuum deposition apparatus. The absorption wavelength in the range of 340 nm to 460 nm was then measured using an ellipsometry (JAWoollam Co. Inc., M-2000X). The results are as follows: Figure 2 As shown.

[0215] like Figure 2 As shown, it can be confirmed that the compound according to the present invention has an absorption intensity of 0.8 or higher, specifically 0.9 or higher, in the ultraviolet region at a wavelength of 380 nm. Compared with the comparative compound and comparative compound 2, its absorption intensity is increased by more than 30%, specifically more than 50%. As described above, the compound according to the present invention exhibits an enhanced absorption wavelength in the ultraviolet region. Therefore, when applied to a capping layer, it can realize an organic light-emitting element with high color purity, high efficiency, and long lifespan.

Claims

1. A compound for use as a coating layer, represented by any one of the following chemical formulas 1 to 3: Chemical Formula 1 Chemical formula 2 Chemical formula 3 Chemical Formula 1-1 In the chemical formulas 1 to 3, A represents chemical formula 1-1. X1 to X8 are each independently C, CR, or N, and only one of them is N. Ar1 to Ar3 are each independently phenyl, biphenyl, terphenyl, naphthyl, pyridyl or a combination thereof, which are substituted or unsubstituted by halogen, nitrile, C1-C6 alkyl, C1-C6 alkoxy, C1-C30 thioether or cyano. R is hydrogen or deuterium. L can be phenylene, biphenylene, terphenylene, naphthylene, pyridylene, or a combination thereof, on its own. L1 and L2 are each independently phenylene, biphenylene, terphenylene, naphthylene, or combinations thereof.

2. The compound for the coating layer according to claim 1, The chemical formula 2 is represented by the following chemical formula 4, or the chemical formula 3 is represented by the following chemical formula 5, which is a coating compound: Chemical Formula 4 Chemical formula 5 In chemical formulas 4 and 5, The definitions of X1, X2, X4 to X8, Ar1 to Ar3, L, L1, and L2 are the same as those in the chemical formulas 1 to 3.

3. The compound for the coating layer according to claim 1, One of X1 to X4 is N.

4. The compound for the coating layer according to claim 1, Chemical formula 1-1 is any one of the structures represented by A-1 to A-7 below: In structures A-1 to A-7, The definition of R is the same as that in Chemical Formula 1. * indicates the position where the amino group is bound via linker L1 or L2.

5. The compound for the coating layer according to claim 4, Chemical formula 1-1 is the structure A-1 or A-2.

6. The compound for the coating layer according to claim 1, The L is any one of the structures represented by B-1 to B-7 below: 。 7. The compound for the coating layer according to claim 6, L refers to structure B-2 or B-3.

8. The compound for the coating layer according to claim 1, L1 and L2 are each independently express: The number l is an integer from 1 to 3.

9. The compound for the coating layer according to claim 1, The compound of chemical formula 1 is any one of the following compounds represented by chemical formulas: 。 10. An organic light-emitting element, comprising: A capping layer comprising the capping compound of any one of claims 1 to 9.

11. The organic light-emitting element according to claim 10, The organic light-emitting element comprises: Electrode 1; The second electrode; and, One or more organic layers are located inside the first electrode and the second electrode; The covering layer is disposed on the outside of either the first electrode or the second electrode.

12. The organic light-emitting element according to claim 10, characterized in that: The coating layer has a refractive index of 2.20 or higher at a wavelength of 450 nm.

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