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

Abstract

The present application provides a compound for a cover layer and an organic light emitting element comprising the compound for a cover layer.

Description

TECHNICAL FIELD

[0001] The present application relates to a novel compound for a cover layer and an organic light emitting element including the same. BACKGROUND

[0002] Materials used as an organic layer in an organic light emitting element can be broadly classified into a light emitting material, a hole injecting material, a hole transporting material, an electron transporting material, and an electron injecting material, according to their functions.

[0003] Further, the light emitting material can be classified into a fluorescent material derived from a singlet excited state of an electron and a phosphorescent material derived from a triplet excited state of an electron, according to a light emitting mechanism, and can be classified into a blue, green, and red light emitting material, according to a light emitting color.

[0004] A general organic light emitting element can have a structure in which an anode is formed on a substrate, and a hole transporting layer, a light emitting layer, an electron transporting layer, and a cathode are sequentially formed on the anode. Among them, the hole transporting layer, the light emitting layer, and the electron transporting layer are organic thin films composed of organic compounds.

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

[0006] When a voltage is applied between the anode and the cathode, holes injected from the anode move to the light emitting layer through the hole transporting layer, and electrons injected from the cathode move to the light emitting layer through the electron transporting layer. The holes and the electrons recombine in the light emitting layer and generate an exciton.

[0007] Light is generated in the process in which the exciton is converted from an excited state to a ground state. The efficiency of an organic light emitting element can be generally classified into internal light emitting efficiency and external light emitting efficiency. The internal light emitting efficiency is related to the efficiency of generating an exciton in an organic layer between a first electrode and a second electrode, such as a hole transporting layer, a light emitting layer, and an electron transporting layer, and achieving light conversion, and it is known that the internal light emitting efficiency of fluorescence is 25% in theory, and the internal light emitting efficiency of phosphorescence is 100%.

[0008] Further, the external light emitting efficiency refers to the efficiency of extracting light generated in an organic layer to the outside of an organic light emitting element, and it is known that about 20% of the internal light emitting efficiency is generally extracted to the outside. As a method for improving the light extraction efficiency, in order to prevent light irradiated to the outside from being lost due to total reflection, a method of using various organic compounds having a refractive index of 1.7 or more as a cover layer is generally used, and in order to improve the performance of an organic light emitting element, an organic compound having a high refractive index and thin film stability that can improve the external light emitting efficiency has been continuously developed. SUMMARY

[0009] Accordingly, an object of the present application is to provide a covering layer compound for an organic light emitting element, which can improve the absorption wavelength of the ultraviolet region while having a wide band gap with difficulty in absorbing the visible light region and a high refractive index, thereby realizing high color purity, high efficiency, and long service life, and an organic light emitting element including the same.

[0010] Further, an object of the present application is to provide a covering layer compound for an organic light emitting element, which can improve the refractive index by optimizing the film arrangement between molecules, can prevent the recrystallization between molecules by a high glass transition temperature (Tg) and a decomposition temperature (Td), and maintain the stability of the film when heat is generated during driving, can improve the stability by protecting the element from external air and moisture, thereby improving the external quantum efficiency and significantly improving the service life, and an organic light emitting element including the same.

[0011] Next, the problems and additional problems as described above will be described in detail.

[0012] As a means to solve the problems as described above,

[0013] In one embodiment of the present application, a covering layer compound represented by the following Chemical Formula 1 is provided:

[0014]

Chemical Formula 1

[0015]

[0016]

Chemical Formula 1-1

[0017]

[0018] In the Chemical Formula 1 and Chemical Formula 1-1,

[0019] Ar1 and Ar2 are each independently a substituted or unsubstituted C6 to C50 aryl group, or a substituted or unsubstituted C2 to C50 heteroaryl group, at least one of Ar1 and Ar2 being a fused aryl group or heteroaryl group,

[0020] Ar3 is Chemical Formula 1-1,

[0021] X1 to X 10 are each independently C, CR, or N, only one of X1 to X 10 is N,

[0022] R is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C1-C30 thio group, substituted or unsubstituted C6-C50 aryl group, or substituted or unsubstituted C2-C50 heteroaryl group, and when R is two or more, they can be the same or different,

[0023] L1and L2are each independently a direct bond, substituted or unsubstituted C6-C50 arylene group, or substituted or unsubstituted C2-C50 heteroarylene group,

[0024] L3is a substituted or unsubstituted C6-C50 arylene group, or substituted or unsubstituted C2-C50 heteroarylene group,

[0025] * is a position bonded to L3, and in the case where L3is a direct bond, a position bonded to N of Chemical Formula 1.

[0026] Further, in an embodiment of the present application,

[0027] An organic light emitting element containing the compound for a cover layer as described above is provided.

[0028] The compound for a cover layer according to the present application has an arylamine structure having a quinoline group bonded thereto, and when applied as a cover layer of an organic light emitting element, can maintain a high refractive index while easily maintaining a wide band gap that is difficult to absorb in the visible light region, and thus can achieve high color purity.

[0029] Further, the compound for a cover layer according to the present application, because the quinoline group and the amine group are extended using a linker, can effectively increase the absorption wavelength in the ultraviolet region while ensuring excellent intermolecular thin film arrangement, and thus can not only improve the refractive index, but also ensure stability when exposed to ultraviolet light, and also easily improve stability when exposed to external air and moisture.

[0030] Furthermore, the compound for a cover layer according to the present application can form a high glass transition temperature (Tg) and a decomposition temperature (Td) by applying a hetero 2-ring fused group such as a quinoline group, and thus when applied as a cover layer of an organic light emitting element, can prevent intermolecular recrystallization and maintain the stability of the thin film when heat is generated during driving of the organic light emitting element.

[0031] Next, the effects and additional effects as described above will be described in detail. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1This is a schematic cross-sectional view illustrating the structure of an organic light-emitting element according to an embodiment of the present invention.

[0033] Figure 2 This is a graph showing the absorption intensity of compounds 47 and 188 used in the capping layer according to an embodiment of the present invention, compared with comparative compounds 1 (Ref. 1) and 2 (Ref. 2), in the range of 340 nm to 460 nm.

[0034] [Symbol Explanation]

[0035] 100: Substrate

[0036] 200: Hole injection layer

[0037] 300: Hole Transport Layer

[0038] 400: Emissive layer

[0039] 500: Electron transport layer

[0040] 600: Electron Injection Layer

[0041] 1000: Electrode 1 (Anode)

[0042] 2000: Second electrode (cathode)

[0043] 3000: Overlay Detailed Implementation

[0044] Before providing a detailed description of the invention, it should be understood that the terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the scope of the invention. The scope of the invention 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.

[0045] 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.

[0046] Throughout this specification and the claims, the term "aryl" refers to substances such as phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrene, triphenylene, phenylene, etc. Benzyl, fluoranyl, benzo[a]fluorene, benzo[a]triphenylene, benzo[a] "aryl" means a C6-C50 aromatic hydrocarbon ring group such as phenyl, naphthyl, stilbenyl, and pyrenyl, and "heteroaryl" means a C2-C50 aromatic ring group containing at least one hetero element such as pyrrolyl, pyrazinyl, pyridyl, indolyl, isoindolyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothienyl, dibenzothienyl, quinolyl, isoquinolyl, quinoxalyl, carbazolyl, phenanthridyl, acridyl, phenanthrolinyl, thienyl, and a hetero ring group composed of pyridine, pyrazine, pyrimidine, pyridazine, triazine, indole, quinoline, acridine, pyrrolidine, di alkyl, piperidine, morpholine, piperazine, carbazole, furan, thiophene, azole, diazole, benz azole, benzofuran, thiazole, thiadiazole, benzothiazole, benzothienyl, benzotriazole, imidazole, benzimidazole, pyran, dibenzofuran, and the like.

[0047] Further, Ar x (wherein x is an integer) means a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, unless explicitly defined otherwise. x (wherein x is an integer) means a directly bonded, substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group, unless explicitly defined otherwise. x (wherein x is an integer) means hydrogen, deuterium, halogen, nitro, nitrile, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C1-C30 thiol group, a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, unless explicitly defined otherwise.

[0048] Throughout the present specification and the claims, the term "substituted or unsubstituted" can mean substituted with any one or more selected from the group consisting of deuterium, halogen, amino, cyano, nitrile group, nitro, nitroso, sulfamoyl, isothiocyanate group, thiocyanate group, carboxyl, or C1 to C30 alkyl group, C1 to C30 alkylsulfinyl group, C1 to C30 alkylsulfonyl group, C1 to C30 alkylsulfanyl group, C1 to C12 fluoroalkyl group, C2 to C30 alkenyl group, C1 to C30 alkoxy group, C1 to C12 N-alkylamino group, C2 to C20 N,N-dialkylamino group, substituted or unsubstituted C1 to C30 mercapto group, C1 to C6 N-alkylsulfamoyl group, C2 to C12 N,N-dialkylsulfamoyl group, C3 to C30 silyl group, C3 to C20 cycloalkyl group, C3 to C20 heterocycloalkyl group, C6 to C50 aryl group, and C3 to C50 heteroaryl group, and the like. Also, throughout the present specification, the same symbols have the same meanings unless explicitly stated otherwise.

[0049] Further, unless explicitly stated otherwise, the embodiments of the present application can be combined with other certain embodiments. Next, the embodiments of the present application and their effects will be described.

[0050] Next, the present application will be described in detail.

[0051] The compound for a cladding layer according to the present application can be represented by the following Chemical Formula 1:

[0052] [Chemical Formula 1]

[0053]

[0054] [Chemical Formula 1-1]

[0055]

[0056] In the Chemical Formula 1 and Chemical Formula 1-1,

[0057] Ar1 and Ar2 are each independently a substituted or unsubstituted C6 to C50 aryl group, or a substituted or unsubstituted C2 to C50 heteroaryl group, at least one of Ar1 and Ar2 is a fused aryl group or heteroaryl group,

[0058] Ar3 is Chemical Formula 1-1,

[0059] X1 to X 10 are each independently C, CR, or N, only one of X1 to X 10 is N,

[0060] R is hydrogen, deuterium, halogen, nitro group, nitrile group, substituted or unsubstituted C1-C30 alkyl group, substituted or unsubstituted C2-C30 alkenyl group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C1-C30 thio group, substituted or unsubstituted C6-C50 aryl group, or substituted or unsubstituted C2-C50 heteroaryl group, and when R is two or more, they can be the same or different,

[0061] L1 and L2 are each independently a direct bond, substituted or unsubstituted C6-C50 arylene group, or substituted or unsubstituted C2-C50 heteroarylene group,

[0062] L3 is a substituted or unsubstituted C6-C50 arylene group, or substituted or unsubstituted C2-C50 heteroarylene group,

[0063] * is a position bonded to L3, and in the case where L3 is a direct bond, a position bonded to N of Chemical Formula 1.

[0064] The compound for a capping layer represented by Chemical Formula 1 according to the present application has an arylamine structure having a quinoline group bonded thereto, and when applied as a capping layer of an organic light emitting element, can maintain a high refractive index while easily maintaining a wide band gap that is difficult to absorb a visible light region, and thus can achieve high color purity.

[0065] Further, the compound for a capping layer represented by Chemical Formula 1 according to the present application, because the quinoline group and the amine group are extended using a linker therebetween, can effectively increase the absorption wavelength in the ultraviolet region while securing excellent intermolecular thin film arrangement, and thus can not only improve the refractive index, but also improve stability when exposed to ultraviolet light and stability when exposed to external air and moisture.

[0066] Furthermore, the compound for a capping layer represented by Chemical Formula 1 according to the present application can form a higher glass transition temperature (Tg) and a decomposition temperature (Td) by applying a hetero 2-ring fused aryl group such as a quinoline group, and thus when applied as a capping layer of an organic light emitting element, can prevent intermolecular recrystallization and maintain the stability of the thin film when heat is generated during driving of the organic light emitting element.

[0067] Specifically, in Chemical Formula 1-1, X1 can be N, and X3 can be bonded to L3. By employing the structure as described above in the compound represented by Chemical Formula 1, it is possible to minimize absorption in the visible light region while achieving a high refractive index.

[0068] Specifically, in the Chemical Formula 1, one or more of Ar1and Ar2may be Chemical Formula 1-1, and in the case where both Ar1and Ar2are Chemical Formula 1-1, Ar1and Ar2may be the same or different. By employing the above structure in the compound represented by the Chemical Formula 1, two or more quinolines can be included and thereby a higher refractive index can be obtained.

[0069] Further, in the Chemical Formula 1, one or more of Ar1and Ar2may be a fused aryl group or a fused heteroaryl group, and specifically, the fused heteroaryl group can be Chemical Formula 1-2. In the case where both Ar1and Ar2are Chemical Formula 1-2, Ar1and Ar2may be the same or different. By employing the above structure in the compound represented by the Chemical Formula 1, a higher refractive index can be obtained while improving the absorption intensity in the ultraviolet region:

[0070]

Chemical Formula 1-2

[0071]

[0072] In the Chemical Formula 1-2,

[0073] X 11 to X 19 Each independently is C, CR, O, S, N, Se, Te, NR, CRR', SiRR', or GeRR'.

[0074] Specifically, the X 15 to X 18 may be CR, the X 12 may be C and can be a bonding site with L1or L2.

[0075] Meanwhile, the X 11 may be CR or N, the X 13 may be O, S, or NR, and the X 14 may be C, or the X 11 may be CR or N, the X 13 may be CR, and the X 14 may be N.

[0076] The compound represented by the Chemical Formula 1 according to the present application can achieve a higher refractive index by including a fused heteroaryl group represented by Chemical Formula 1-1 in Ar3while including a fused aryl group or a fused heteroaryl group represented by Chemical Formula 1-2 having a different structure from Chemical Formula 1-1 in one or more of Ar1and Ar2. Specifically, Ar1may be Chemical Formula 1-1, and Ar2may be Chemical Formula 1-2.

[0077] Further, the chemical formula 1 according to the present application can be represented by the following chemical formula 2. In the case of the above, the compound for the cover layer represented by the chemical formula 1 can minimize the absorption wavelength of the blue region by connecting to the amine group through the phenylene group adjacent to the chemical formula 1-1, and also can effectively increase the refractive index:

[0078] [Chemical formula 2]

[0079]

[0080] In the chemical formula 2,

[0081] Ar1, Ar2, L1, L2, X1 to X 10 The same as the chemical formula 1,

[0082] R1 is the same as R of the chemical formula 1 (where the number of carbons of R1 satisfies the range of the number of carbons defined in L3),

[0083] 1 is an integer of 1 to 5, and specifically, 1 can be 1 to 3.

[0084] Specifically, the chemical formula 1 can be represented by any one of the chemical formula 3 to the chemical formula 5:

[0085] [Chemical formula 3]

[0086]

[0087] [Chemical formula 4]

[0088]

[0089] [Chemical formula 5]

[0090]

[0091] In the chemical formula 3 to the chemical formula 5,

[0092] Ar1, Ar2, X1 to X 10 The same as the chemical formula 1 (where the number of carbons of X1 to X 10 satisfies the range of the number of carbons defined in Ar1 or Ar2),

[0093] L1 and L2 are each independently a direct bond, a substituted or unsubstituted C6 to C50 arylene group, or a substituted or unsubstituted C2 to C50 heteroarylene group, and specifically, a substituted or unsubstituted C6 to C50 arylene group, or a substituted or unsubstituted C2 to C50 heteroarylene group,

[0094] m is an integer of 1 to 3, and specifically, m can be 1 or 2.

[0095] The compound represented by Chemical Formula 3 to Chemical Formula 5 is a compound in which any one or more of Ar1 to Ar3 is Chemical Formula 1-1, and L3 is a para-phenylene (1,4-phenylene) that enables extension of the linker (in the case of m = 2 to 3). In the case of the above, the compound can increase the refractive index while increasing the absorption wavelength in the ultraviolet region, thereby improving stability when exposed to external ultraviolet rays.

[0096] In particular, as shown in the compound represented by Chemical Formula 4 and / or Chemical Formula 5, in the case of containing 2 or more fused heteroaryl groups, the refractive index can be further increased.

[0097] Further, because L1 and L2 each independently contain a structure of arylene or heteroarylene, the absorption intensity in the ultraviolet region can be improved while increasing the refractive index.

[0098] Meanwhile, the Chemical Formula 1 can be represented by any one of the following Chemical Formula 6 to Chemical Formula 9:

[0099] [Chemical Formula 6]

[0100]

[0101] [Chemical Formula 7]

[0102]

[0103] [Chemical Formula 8]

[0104]

[0105] [Chemical Formula 9]

[0106]

[0107] In the Chemical Formula 6 to Chemical Formula 9,

[0108] Ar1, L1, L2, X1 to X 10 The same as the Chemical Formula 1,

[0109] X 11 , X 13 , and X 14 each independently C, O, S, N, CR, or NR,

[0110] m is an integer of 1 to 3, and specifically, m can be 1 or 2.

[0111] The compound represented by the Chemical Formula 6 to the Chemical Formula 9 is a compound in which L3 includes a para-phenylene (1,4-phenylene) which enables extension of the linking group (in the case of m = 2 ~ 3) and any one or more of Ar1and Ar2include the Chemical Formula 1-2. In the case as described above, the absorption intensity in the ultraviolet region can be improved and a higher refractive index can be achieved.

[0112] Specifically, in the compound represented by the Chemical Formula 6 and the Chemical Formula 7, X 11 may be CR or N, X 13 may be O or S, in the case as described above, a high refractive index can be obtained, and in particular, the absorption intensity can be more effectively improved. Further, in the compound represented by the Chemical Formula 8 or the Chemical Formula 9, X 11 may be CR or N, X 14 may be N, in the case as described above, the absorption in the visible light region can be minimized while having a high refractive index, and in addition, the thermal stability can be effectively improved.

[0113] Further, any one of X1to X4may be N. The Chemical Formula 1-1 in which any one of X1to X4is N is a quinoline group, and in the case of including the same in the compound represented by the Chemical Formula 1, not only a higher refractive index can be obtained because the polarizability in the molecule is high, but also the light absorption intensity in the ultraviolet region can be effectively improved.

[0114] As an example, the Chemical Formula 1 can be represented by any one of the following Chemical Formula 10 to Chemical Formula 12:

[0115] [Chemical Formula 10]

[0116]

[0117] [Chemical Formula 11]

[0118]

[0119] [Chemical Formula 12]

[0120]

[0121] In the Chemical Formula 10 to Chemical Formula 12,

[0122] Ar1, Ar2, L1, and L2 are the same as the Chemical Formula 1,

[0123] m is an integer of 1 to 3, and specifically, m can be 1 or 2.

[0124] The compounds represented by Chemical Formula 10 to Chemical Formula 12 are compounds in which L3 is a para-phenylene group (1,4-phenylene group) that enables extension of the linking group (in the case of m = 2 to 3) and any one or more of Ar1 to Ar3 is a quinolinyl group. By employing the structure as described above in the compounds represented by Chemical Formula 10 to Chemical Formula 12, it is possible to have a high refractive index while minimizing light absorption in the visible light region.

[0125] Further, in Chemical Formula 1, L1 to L3 can each independently be a phenylene group, a biphenylene group, or a combination thereof. As an example, L1 to L3 can each independently be a 1,4-phenylene group or a 1,4-biphenylene group, and in particular, L1 to L3 can all be 1,4-phenylene groups or L1 and L2 can be 1,4-phenylene groups and L3 can be a 1,4-biphenylene group, and in the case as described above, it is possible to reduce the deposition temperature while maintaining a high refractive index by minimizing the volume characteristics of the linking group adjacent to the amine.

[0126] Further, Ar1 and Ar2 can each independently be a fused aryl group composed of 2 rings or a fused heteroaryl group composed of 2 rings.

[0127] In the case where Ar1 and Ar2 are a fused aryl group composed of 2 rings, it is possible to exhibit a high refractive index while minimizing absorption in the visible light region, and in the case where Ar1 and Ar2 are a fused heteroaryl group composed of 2 rings, it is possible to not only exhibit a high refractive index but also enhance absorption in the ultraviolet region.

[0128] As an example, Ar1 and Ar2 can each independently be selected from the group consisting of a benzofuranyl group, a benzothienyl group, an indolizinyl group, an imidazopyridinyl group, and a benzoxazolyl group, whereby the compound for a cover layer represented by Chemical Formula 1 can maintain a high refractive index by minimizing the volume characteristics of the terminal group, and at the same time, it is also possible to effectively improve the deposition temperature. As an example, Ar1 and Ar2 can each independently be selected from the group consisting of a benzofuranyl group, a benzothienyl group, an indolizinyl group, an imidazopyridinyl group, and a benzoxazolyl group, whereby the compound for a cover layer represented by Chemical Formula 1 can maintain a high refractive index by minimizing the volume characteristics of the terminal group, and at the same time, it is also possible to effectively improve the deposition temperature.

[0129] The following compounds are specific examples of the compounds according to the present application. The following examples are merely illustrative of the present application and do not limit the present application thereto:

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160] One embodiment of the present application can be synthesized by an amination reaction, and the general synthetic reaction formula is shown below.

[0161]

[0162] In another embodiment of the present application, there is provided an organic light emitting device including a covering layer compound according to the present application as described above.

[0163] Next, the organic light emitting device according to the present application will be described in more detail.

[0164] In one embodiment of the present application, the organic light emitting device can include a first electrode, a second electrode, one or more organic layers interposed between the first electrode and the second electrode, and a covering layer, which can be disposed outside one or more of the first electrode and the second electrode.

[0165] Specifically, one side of the first electrode or the second electrode, which is adjacent to the organic layer interposed between the first electrode and the second electrode, is referred to as the inner side, and the other side, which is not adjacent to the organic layer, is referred to as the outer side. That is, when the covering layer is disposed outside the first electrode, the first electrode is interposed between the covering layer and the organic layer, and when the covering layer is disposed outside the second electrode, the second electrode is interposed between the covering layer and the organic layer.

[0166] Further, in one embodiment of the present application, the inner sides of the first electrode and the second electrode of the organic light emitting device can be interposed with one or more organic layers, and the covering layer can be formed outside one or more of the first electrode and the second electrode. That is, the covering layer can be formed outside both the first electrode and the second electrode, or can be formed outside only the first electrode or the second electrode.

[0167] At this time, the covering layer can include the covering layer compound according to the present application, can include the covering layer compound according to the present application alone or two or more kinds thereof, or can include a known compound.

[0168] Further, the covering layer can have a refractive index of 2.25 or more at a wavelength of 450 nm, specifically 2.30 or more, more specifically 2.32 or more, and can have an ultraviolet absorption intensity of 0.7 or more at a wavelength of 380 nm, specifically 0.8 or more or 0.9 or more.

[0169] Further, the organic layer can include a hole transport layer, a light emitting layer, and an electron transport layer, which are generally included in a light emitting portion, but is not limited thereto.

[0170] Specifically, the organic light emitting element according to an embodiment of the present application can include one or more organic layers constituting a light emitting portion such as a hole injection layer (HIL), a hole transport layer (HTL), an emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) between a first electrode (anode) and a second electrode (cathode).

[0171] Figure 1 is a cross-sectional view schematically illustrating a configuration of an organic light emitting element according to an embodiment of the present application. The organic light emitting element according to an embodiment of the present application can be manufactured in a structure as shown in Figure 1 .

[0172] As shown in Figure 1 , 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, an emitting layer 400, an electron transport layer 500, an electron injection layer 600, a second electrode 2000, and a cover layer 3000 are sequentially stacked from bottom to top.

[0173] The substrate 100 can use a substrate commonly used in an organic light emitting element, and particularly, a transparent glass substrate or a flexible plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, handling convenience, and water resistance can be used.

[0174] Further, the first electrode 1000 is used as a hole injection electrode for injecting holes in the organic light emitting element. The first electrode 1000 is manufactured using a material having a work function as low as possible in order to achieve injection of holes, and can be formed using a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene.

[0175] Meanwhile, the hole injection layer 200 can be formed by depositing a hole injection layer material on the upper portion of the first electrode 1000 using a method such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett (LB) method, or the like. When the hole injection layer 200 is formed by the vacuum deposition method, the deposition conditions can vary depending on a compound used as a material of the hole injection layer 200, a structure and thermal characteristics of the hole injection layer 200 required, and the like, and generally, a deposition temperature of 50 to 500°C, a vacuum degree of 10 -8 to 10 -3 torr, a deposition rate of 0.01 to 10 A / sec, and a deposition rate of 0.01 to 10 A / sec can be used. ​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).

[0176] 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 1 Although not illustrated, a light-emitting auxiliary layer can be added above the hole transport layer 300.

[0177] 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.

[0178] 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), phenanthrolines (e.g., UDC's BCP), etc. The light-emitting layer 400 of the present invention, as described above, may include one or more blue light-emitting layers.

[0179] Further, the electron transport layer 500 is formed on the upper portion of the light emitting layer 400, and can be formed by a method such as a vacuum deposition method, a spin coating method, a casting method, etc. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally selected within a range of conditions almost the same as those for forming the hole injection layer 200.

[0180] Further, the electron injection layer 600 can be formed by depositing an electron injection layer material on the upper portion of the electron transport layer 500, and can be formed by a method such as a vacuum deposition method, a spin coating method, a casting method, etc.

[0181] Meanwhile, the second electrode 2000 is used as an electron injection electrode, and can be formed on the upper portion of the electron injection layer 600 by a method such as a vacuum deposition method or a spin coating method. As a material for the second electrode 2000, various metals can be used. As specific examples, there are included materials such as aluminum, gold, silver, magnesium, etc., but are not limited thereto.

[0182] The organic light emitting element of the present application can use not only the organic light emitting element including the cover 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 cover layer 3000 as described above, but also various structures of organic light emitting elements, and can additionally include one or two intermediate layers as needed.

[0183] Further, the thickness of each organic layer formed by the present application can be adjusted according to the degree required, and can be 1 to 1000 nm in detail, and 1 to 150 nm more specifically.

[0184] The cover layer 3000 can be formed on the outer side of the first electrode 1000, which is not formed with the hole injection layer 200, among the two side surfaces of the first electrode 1000. Further, it can be formed on the outer side of the second electrode 2000, which is not formed with the electron injection layer 600, among the two side surfaces of the second electrode 2000, but is not limited thereto. The cover layer 3000 as described above can be formed by a deposition process, and the thickness of the cover layer 3000 can be 100 to 1000 nm in detail, and 300 to 800 nm more specifically. More specifically, it can be 300 to 800 nm. By the thickness adjustment method as described above, the problem of a decrease in the transmittance of the cover layer 3000 can be prevented.

[0185] Further, although the cover layer 3000 is formed on the outer side of the first electrode 1000 and the second electrode 2000 as described above, it is not limited thereto. Figure 1The organic layer for various functions is additionally formed between the cover layer 3000 and the first electrode 1000 or between the cover layer 3000 and the second electrode 2000, but is not limited thereto. The organic layer for various functions can be additionally formed on the upper portion (outer surface) of the cover layer 3000.

[0186] Next, the present application will be described in more detail by a synthesis example of a compound according to an embodiment of the present application and an example of an organic light emitting device. The following synthesis example and example are only for exemplifying the present application, and the scope of the present application is not limited to the following examples.

[0187] <SYNTHESIS EXAMPLE 1> Synthesis of Compound 37

[0188]

[0189] A round bottom flask was charged with 100 ml of toluene, and 2.0 g of 2-(4-bromophenyl)naphthalene, 3.29 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 therein, followed by reflux stirring. The reaction was confirmed by thin layer chromatography (TLC), and the reaction was completed after adding water. The organic layer was extracted with dichloromethane (MC), and recrystallized after filtration under reduced pressure, thereby obtaining 2.9 g of compound 37 (yield: 66%).

[0190] m / z: 625.25 (100.0%), 626.26 (50.1%), 627.26 (12.3%), 628.26 (2.1%), 626.25 (1.1%)

[0191] <SYNTHESIS EXAMPLE 2> Synthesis of Compound 47

[0192]

[0193] Compound 47 was synthesized in the same manner as in Synthesis Example 1, using the same equivalent of 3-(4-bromophenyl)quinoline instead of 2-(4-bromophenyl)naphthalene (yield: 67%).

[0194] m / z: 626.25 (100.0%), 627.25 (49.0%), 628.25 (12.3%), 629.26 (1.8%), 627.24 (1.5%)

[0195] <synthesis example 3> Synthesis of compound 181

[0196]

[0197] The same method as synthesis example 1 was performed, wherein the same equivalent of 3-(4-bromophenyl)quinoline and bis(4-(benzofuran-2-yl)phenyl)amine was used instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine to synthesize compound 181 (yield 65%).

[0198] m / z: 604.22 (100.0%), 605.22 (46.9%), 606.22 (11.5%), 607.23 (1.6%)

[0199] <synthesis example 4> Synthesis of compound 182

[0200]

[0201] The same method as synthesis example 1 was performed, wherein the same equivalent of 2-(4-bromophenyl)benzofuran was used instead of 2-(4-bromophenyl)naphthalene to synthesize compound 182 (yield 64%).

[0202] m / z: 615.23 (100.0%), 616.23 (48.7%), 617.24 (11.4%), 618.24 (1.8%)

[0203] <synthesis example 5> Synthesis of compound 183

[0204]

[0205] The same method as in Synthesis Example 1 was performed, wherein the same equivalent of 3-(4-bromophenyl)quinoline and bis(4-(benzo[b]thiophen-2-yl)phenyl)amine were used instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine to synthesize Compound 183 (yield 65%).

[0206] m / z: 636.17 (100.0%), 637.17 (48.8%), 638.18 (10.7%), 638.17 (10.1%), 639.17 (4.3%), 639.18 (1.8%), 640.17 (1.0%)

[0207] <SYNTHESIS EXAMPLE 6> Synthesis of Compound 184

[0208]

[0209] The same method as in Synthesis Example 1 was performed, wherein the same equivalent of 2-(4-bromophenyl)benzo[b]thiophene was used instead of 2-(4-bromophenyl)naphthalene to synthesize Compound 184 (yield 66%).

[0210] m / z: 631.21 (100.0%), 632.21 (49.8%), 633.21 (12.0%), 633.20 (4.5%), 634.21 (2.4%), 634.22 (1.7%)

[0211] <SYNTHESIS EXAMPLE 7> Synthesis of Compound 187

[0212]

[0213] The same method as in Synthesis Example 1 was performed, wherein the same equivalent of 3-(4-bromophenyl)quinoline and bis(4-(benzo[d] Compound 187 was synthesized (yield 68%) according to the same method as in the synthetic example 1, wherein bis(4-(benzo[d]oxazol-2-yl)phenyl)amine was used instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine.

[0214] m / z: 606.21 (100.0%), 607.21 (44.7%), 608.21 (10.7%), 607.20 (1.5%), 609.22 (1.4%)

[0215] <synthesis example 8> synthesis of compound 188

[0216]

[0217] was performed according to the same method as in the synthetic example 1, wherein the same equivalent of 3-(4-bromophenyl)quinoline and bis(4-(imidazo[l,2-a]pyridin-2-yl)phenyl)amine were used instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine. Compound 188 was synthesized (yield 67%) according to the same method as in the synthetic example 1, wherein bis(4-(benzo[d]oxazol-2-yl)phenyl)amine was used instead of 2-(4-bromophenyl)naphthalene.

[0218] m / z: 616.23 (100.0%), 617.23 (46.9%), 618.23 (11.5%), 619.24 (1.6%), 617.22 (1.5%)

[0219] <synthesis example 9> synthesis of compound 195

[0220]

[0221] was performed according to the same method as in the synthetic example 1, wherein the same equivalent of 3-(4-bromophenyl)quinoline and bis(4-(imidazo[l,2-a]pyridin-2-yl)phenyl)amine were used instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine.

[0222] m / z: 604.24 (100.0%), 605.24 (44.7%), 606.24 (10.6%), 605.23 (2.2%), 607.25 (1.4%)

[0223] <SYNTHESIS EXAMPLE 10> Synthesis of Compound 196

[0224]

[0225] The same method as in Synthesis Example 1 was performed, wherein the same equivalent of 2-(4-bromophenyl)imidazo[l,2-a]pyridine was used instead of 2-(4-bromophenyl)naphthalene to synthesize Compound 196 (yield 60%).

[0226] m / z: 615.24 (100.0%), 616.25 (46.8%), 617.25 (10.7%), 616.24 (1.8%), 618.25 (1.8%)

[0227] <SYNTHESIS EXAMPLE 11> Synthesis of Compound 48

[0228]

[0229] The same method as in Synthesis Example 1 was performed, wherein the same equivalent of 3-(4'-bromo-[l,l'-biphenyl]-4-yl)quinoline was used instead of 2-(4-bromophenyl)naphthalene to synthesize Compound 48 (yield 65%).

[0230] m / z: 702.28 (100.0%), 703.28 (57.0%), 704.29 (15.1%), 705.29 (2.7%)

[0231] <SYNTHESIS EXAMPLE 12> Synthesis of Compound 197

[0232]

[0233] The same procedure as in Synthesis Example 1 was followed, using 3-(4'-bromo- [1,1'-biphenyl]-4-yl)quinoline and bis(4-(benzo[b]thiophen-2-yl)phenyl)amine instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, respectively, to synthesize Compound 199 (yield 66%).

[0234] m / z: 680.25 (100.0%), 681.25 (53.4%), 682.25 (14.6%), 683.26 (2.4%)

[0235] <SYNTHESIS EXAMPLE 13> Synthesis of Compound 199

[0236]

[0237] The same procedure as in Synthesis Example 1 was followed, using 3-(4'-bromo- [1,1'-biphenyl]-4-yl)quinoline and bis(4-(benzo[b]thiophen-2-yl)phenyl)amine instead of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine, respectively, to synthesize Compound 199 (yield 66%).

[0238] m / z: 712.20 (100.0%), 713.20 (55.3%), 714.21 (14.0%), 714.20 (10.3%), 715.20 (5.0%), 715.21 (2.6%), 716.20 (1.4%)

[0239] <SYNTHESIS EXAMPLE 14> Synthesis of Compound 201

[0240]

[0241] The same procedure as in Synthesis Example 1 was followed, wherein the same equivalents of 3-(4'-bromo-[l,l'-biphenyl]-4-yl)quinoline and bis(4-(benzo[d]oxazol-2-yl)phenyl)amine were used in place of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine to synthesize Compound 201 (yield 60%). The same procedure as in Synthesis Example 1 was followed, wherein the same equivalents of 3-(4'-bromo-[l,l'-biphenyl]-4-yl)quinoline and bis(4-(benzo[d]oxazol-2-yl)phenyl)amine were used in place of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine to synthesize Compound 201 (yield 60%).

[0242] m / z: 682.24 (100.0%), 683.24 (51.3%), 684.24 (13.9%), 685.25 (2.1%), 683.23 (1.5%)

[0243] <SYNTHESIS EXAMPLE 15> Synthesis of Compound 207

[0244]

[0245] The same procedure as in Synthesis Example 1 was followed, wherein the same equivalents of 3-(4'-bromo-[l,l'-biphenyl]-4-yl)quinoline and bis(4-(benzo[d]oxazol-2-yl)phenyl)amine were used in place of 2-(4-bromophenyl)naphthalene and bis(4-(quinolin-3-yl)phenyl)amine to synthesize Compound 201 (yield 60%).

[0246] m / z: 682.24 (100.0%), 683.24 (51.3%), 684.24 (13.9%), 685.25 (2.1%), 683.23 (1.5%)

[0247] Manufacture of organic light emitting elements

[0248] Figure 1 is a schematic diagram illustrating the structure of a general organic light emitting element, as an example of the present application, in Figure 1On the basis of the structure of the illustrated organic light emitting element, a charge generation layer (not shown) is additionally introduced between the hole injection layer 200 and the hole transport layer 300, and an electron injection layer (not shown) is additionally introduced between the electron transport layer 500 and the cathode 2000. Specifically, the manufactured organic light emitting element is formed by sequentially stacking, from the bottom up, the 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) / cover layer 3000.

[0249] In manufacturing the organic light emitting element, the substrate 10 can be a transparent glass substrate or a flexible plastic substrate.

[0250] The hole injection electrode 1000 is used as an anode for injecting holes in the organic light emitting element. In order to achieve injection of holes, a substance having a work function as low as possible is used, and can be formed using a transparent material such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene.

[0251] In the hole injection layer 200, the charge generation layer, the hole transport layer 300, the light emitting layer 400, the electron transport layer 500, and the electron injection layer 600, the substances shown in Table 1 below are used.

[0252] Further, on the upper side of the electron injection layer 600, a cathode 2000 for injecting electrons is formed. As the cathode, various metals can be used. As specific examples, substances such as aluminum, gold, and silver are included.

[0253] [Table 1]

[0254]

[0255] <Example 1>

[0256] An indium tin oxide (ITO) substrate on which a reflective layer containing silver (Ag) was formed was washed with distilled water using ultrasonic waves. After the distilled water washing was completed, ultrasonic washing was performed using solvents such as isopropyl alcohol, acetone, and methanol, and drying was performed. Next, HIOl was formed as a hole injection layer on the upper portion of the indium tin oxide (ITO) substrate. HATCN was formed as a charge generation layer Next, HT01 was formed as a hole transport layer Next, BD01 was doped at 3% by weight in the main body BH01 to form a light emitting layer having a thickness of 100 nm. Next, a mixture of ET01 and Liq (1:1, wt. / wt.) was used to form an electron transport layer having a thickness of 50 nm, and then a cathode having a thickness of 15 nm was formed by deposition using MgAg. On the upper side of the cathode, a cover layer having a thickness of 10 nm was formed by deposition using the compound manufactured in Synthesis Example 1. an electron transport layer having a thickness of 50 nm, and then a cathode having a thickness of 15 nm was formed by deposition using MgAg. On the upper side of the cathode, a cover layer having a thickness of 10 nm was formed by deposition using the compound manufactured in Synthesis Example 1. an electron transport layer having a thickness of 50 nm, and then a cathode having a thickness of 15 nm was formed by deposition using MgAg. On the upper side of the cathode, a cover layer having a thickness of 10 nm was formed by deposition using the compound manufactured in Synthesis Example 1.

[0257] <Example 2> to <Example 15>

[0258] an electron transport layer having a thickness of 50 nm, and then a cathode having a thickness of 15 nm was formed by deposition using MgAg. On the upper side of the cathode, a cover layer having a thickness of 10 nm was formed by deposition using the compound manufactured in Synthesis Example 1.

[0259] <Comparative Example 1> to <Comparative Example 5>

[0260] an electron transport layer having a thickness of 50 nm, and then a cathode having a thickness of 15 nm was formed by deposition using MgAg. On the upper side of the cathode, a cover layer having a thickness of 10 nm was formed by deposition using the compound manufactured in Synthesis Example 1.

[0261] [Table 2]

[0262]

[0263] <Test Example 1> Performance Evaluation of Organic Light Emitting Element

[0264] The performance of the organic light emitting elements of the Examples 1 to 10 and Comparative Examples 1 to 5, i.e., the current density and the luminance with respect to the applied voltage, were evaluated under atmospheric pressure conditions by injecting electrons and holes by loading a voltage to a Kiethley 2400 source measurement unit and measuring the luminance of the emitted light using a Konica Minolta spectroradiometer (CS-2000), and the results are shown in Table 3.

[0265] [Table 3]

[0266] Op. V mA / cm 2 ]] Cd / A CIEx CIEy LT97 Example 1 3.45 10 7.78 0.140 0.044 158 Example 2 3.44 10 7.91 0.141 0.043 165 Example 3 3.44 10 8.05 0.139 0.045 171 Example 4 3.45 10 8.02 0.140 0.044 172 Example 5 3.44 10 8.10 0.141 0.043 172 Example 6 3.45 10 8.06 0.141 0.042 172 Example 7 3.44 10 8.07 0.140 0.044 178 Example 8 3.45 10 8.06 0.141 0.043 177 Example 9 3.44 10 8.05 0.140 0.045 182 Example 10 3.45 10 8.05 0.140 0.044 180 Example 11 3.43 10 8.30 0.140 0.043 190 Example 12 3.43 10 8.35 0.140 0.043 193 Example 13 3.43 10 8.60 0.140 0.042 206 Example 14 3.43 10 8.74 0.140 0.042 212 Example 15 3.43 10 8.43 0.140 0.042 199 Comparative Example 1 3.46 10 6.93 0.136 0.052 105 Comparative Example 2 3.47 10 5.98 0.133 0.059 77 Comparative Example 3 3.46 10 7.00 0.136 0.051 116 Comparative Example 4 3.46 10 6.82 0.135 0.054 110 Comparative Example 5 3.51 10 4.25 0.130 0.072 44

[0267] As can be seen by comparing the Examples of the present application, the organic light emitting elements of the Examples can achieve a lower driving voltage, and their luminous efficiency and service life are also significantly improved.

[0268] Specifically, the organic light emitting element according to the embodiment of the present application can achieve high color purity, as compared with the organic light emitting element of Comparative Example 1, because the compound constituting the cover layer has an arylamine structure having a quinoline group bonded thereto, thus maintaining a wide band gap difficult to absorb a visible light region while maintaining a high refractive index.

[0269] Further, the organic light emitting element of the embodiment can achieve an organic light emitting element having a long service life, as compared with the organic light emitting element of Comparative Example 2, because the quinoline group in the compound constituting the cover layer is bonded to the N of the arylamine through a linker, thus minimizing the bulk property and thereby ensuring excellent thin film alignment, and further increasing the refractive index while increasing the absorption wavelength in the ultraviolet region.

[0270] Meanwhile, the organic light emitting element of the embodiment can form a stable thin film while improving the refractive index, as compared with the organic light emitting elements of Comparative Examples 3 and 4, because the compound constituting the cover layer contains a hetero 2-ring structure having a different structure from the quinoline group, thus further increasing the polarizability of the molecule and forming a higher glass transition temperature (Tg).

[0271] Further, the organic light emitting element of the embodiment can achieve an organic light emitting element having high efficiency, high color purity, and a long service life, as compared with the organic light emitting element of Comparative Example 5, because the compound constituting the cover layer has a structure in which a ring containing N in the quinoline group is connected to the N side of the arylamine, thus increasing the absorption intensity in the ultraviolet region while having a high refractive index, and further minimizing the absorption wavelength in the visible light region.

[0272] <Test Example 2> Refractive Index Evaluation

[0273] A deposition film having a thickness of 30 nm was manufactured on a silicon substrate using a vacuum deposition device using the compound used to form the cover layer in the embodiment and the comparative examples, specifically, Compounds 37, 47, 181, 182, 183, 184, 187, 188, 195, 196, 48, 197, 199, 201, and 207, and Comparative Compounds 1 (Ref. 1) to 5 (Ref. 5) of Table 2 above, and the refractive index at a wavelength of 450 nm was measured using an ellipsometer device (J. A. Woollam Co. Inc, M-2000X). The results are shown in Table 4 below.

[0274] [Table 4]

[0275] @ 450 nm Refractive index, n Compound 37 2.32 Compound 47 2.35 Compound 181 2.38 Compound 182 2.36 Compound 183 2.40 Compound 184 2.38 Compound 187 2.38 Compound 188 2.38 Compound 195 2.37 Compound 196 2.37 Compound 48 2.43 Compound 197 2.47 Compound 199 2.48 Compound 201 2.44 Compound 207 2.45 Comparative Compound 1 (Ref. 1) 2.15 Comparative Compound 2 (Ref. 2) 2.06 Comparative Compound 3 (Ref. 3) 2.16 Comparative Compound 4 (Ref. 4) 2.13 Comparative Compound 5 (Ref. 5) 2.05

[0276] As shown in Table 4, it can be confirmed that the refractive index of the compounds according to the present invention can be 2.25 or higher, specifically 2.30 or higher, and up to 2.32 or higher. As described above, because the compounds according to the present invention can exhibit high refractive indices, organic light-emitting elements with significantly improved external quantum efficiency and lifespan can be achieved when applied to a capping layer.

[0277] <Experimental Example 3> Evaluation of Ultraviolet Absorption Intensity

[0278] Using compounds 47 and 188, which were used in forming the capping layer in Examples 2 and 8, and comparative compounds 1 (Ref. 1) and 2 (Ref. 2), which were 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 ellipsometer (JAWoollam Co. Inc., M-2000X). The results are as follows: Figure 2 As shown.

[0279] like Figure 2 As shown, it can be confirmed that compounds 47 and 188 according to the present invention have an absorption intensity of 0.7 or higher, specifically 0.8 or higher, in the ultraviolet region at a wavelength of 380 nm. Compared with comparative compounds (Ref. 1) and (Ref. 2), their absorption intensity is increased by more than 40%, specifically more than 60%. As described above, the compounds according to the present invention exhibit an enhanced absorption wavelength in the ultraviolet region, and therefore, when applied to a capping layer, organic light-emitting elements with high color purity, high efficiency, and long lifespan can be realized.

Claims

1. A cover layer comprising a cover layer compound represented by the following Chemical Formula 2: Chemical Formula 2 In the Chemical Formula 2, Ar1and Ar2are each independently a C6 to C50 fused aryl group consisting of 2 rings or a C2 to C50 fused heteroaryl group consisting of 2 rings, X1is N, X2to X 10 each independently C or CR, or X9is N, X1to X8and X 10 each independently C or CR, R and R1are hydrogen or deuterium, L1and L2are each independently a direct bond, a phenylene group, a biphenylene group, or a combination thereof, l is an integer of 1 to 5 and does not include 1.

2. The cover layer comprising a cover layer compound according to claim 1, one or more of Ar1and Ar2is the following Chemical Formula 1-1, Chemical Formula 1-1 In the above Chemical Formula 1-1, X1is N, X2to X 10 each independently C or CR, or X9is N, X1to X8and X 10 each independently C or CR, R is hydrogen, * is a bonding position.

3. The cover layer comprising a cover layer compound according to claim 1, one or more of Ar1and Ar2is the following Chemical Formula 1-2: Chemical Formula 1-2 In the Chemical Formula 1-2, X 11 to X 19 each independently C, CR, O, S, N, Se, Te or NR, R being hydrogen.

4. The cover layer comprising a cover layer compound according to claim 1, the Chemical Formula 2 is represented by any one of the following Chemical Formula 3 to Chemical Formula 5: Chemical Formula 3 Chemical Formula 4 Chemical Formula 5 In the Chemical Formula 3 to Chemical Formula 5, Ar1, Ar2, L1, L2, and X1to X 10 the same as the chemical formula 2, and R is hydrogen, wherein, X1to X 10 the number of carbons satisfies the range of the number of carbons defined in Ar1or Ar2, m is an integer of 1 to 3 and does not include 1.

5. The cover layer comprising a cover layer compound according to claim 1, the Chemical Formula 2 is represented by any one of the following Chemical Formula 6 to Chemical Formula 9: Chemical Formula 6 Chemical Formula 7 Chemical Formula 8 Chemical Formula 9 In the Chemical Formula 6 to Chemical Formula 9, Ar1, L1, L2, X1to X 10 The same as Chemical Formula 2, X 11 , X 13 and X 14 are each independently C, O, S, N, CR or NR, and R is hydrogen, m is an integer from 1 to 3 and does not include 1.

6. The cap layer comprising a compound for a cap layer according to claim 5, X 11 is CR or N, X 13 is O or S, X 14 is N, R is hydrogen.

7. The cover layer comprising a cover layer compound according to claim 1, the Chemical Formula 2 is represented by any one of the following Chemical Formula 10 to Chemical Formula 12: Chemical Formula 10 Chemical Formula 11 Chemical Formula 12 In the Chemical Formula 10 to Chemical Formula 12, Ar1, Ar2, L1, and L2are the same as the Chemical Formula 2, m is an integer of 1 to 3 and does not include 1.

8. The cover layer comprising a cover layer compound according to claim 1, L1to L2are each independently a phenylene group, a biphenylene group, or a combination thereof. Ar1 and Ar2 are each independently derived from benzofuranyl, benzothiopheneyl, indoleazinyl, imidazopyridyl, and benzofuranyl. Choose from the group consisting of azole groups.

9. The cover layer comprising a cover layer compound according to claim 1, 10. The cover layer comprising a cover layer compound according to claim 1, the compound of the Chemical Formula 2 is any one of the compounds represented by the following Chemical Formula:

11. An organic light emitting element comprising: the cover layer according to any one of claims 1 to 10.

12. The organic light emitting element according to claim 11, the organic light emitting element comprising: a first electrode and a second electrode; and, one or more organic layers between the inside of the first electrode and the second electrode; the cover layer is disposed outside one or more of the first electrode and the second electrode. The thickness of the cover layer is from 0.1 to 10 mm 13. The organic light emitting element according to claim 11, 14. The organic light emitting element according to claim 11, the refractive index of the cover layer at a wavelength of 450 nm is 2.25 or more.

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