Novel compound for covering layer and organic light emitting element containing the compound for covering layer

Abstract

The present invention provides a compound for a covering layer represented by the following chemical formula 1 and an organic light-emitting element including the compound for a covering layer.

Description

Technical Field

[0001] The present invention relates to a compound for a covering layer and an organic light-emitting element comprising the compound for a covering layer. Background Art

[0002] Materials used as the organic layer in an organic light-emitting element can be roughly divided into light-emitting materials, hole injection materials, hole transport materials, electron transport materials, and electron injection materials according to their functions.

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

[0004] A common organic light-emitting element may adopt a structure in which an anode is formed on the upper part of a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer and a cathode are sequentially formed on the upper part of the anode. Among them, 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 having the above structure is as follows.

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

[0007] Light is generated during the conversion of the excitons from the excited state to the ground state. The efficiency of an organic light-emitting element can generally be divided into internal luminescence efficiency and external luminescence efficiency. The internal luminescence efficiency is related to the efficiency of generating excitons and realizing light conversion in organic layers such as the hole transport layer, the light-emitting layer, and the electron transport layer between the first electrode and the second electrode. Theoretically, the internal luminescence efficiency of fluorescence is 25%, while that of phosphorescence is 100%.

[0008] In addition, the external luminous efficiency refers to the efficiency of light generated in the organic layer being extracted to the outside of the organic light-emitting element. It is known that generally about 20% of the internal luminous efficiency can be extracted to the outside. As a method of improving the above light extraction efficiency, in order to prevent the light irradiated to the outside from being lost due to total reflection, various organic compounds with a refractive index of 1.7 or more are usually used as a covering layer. In order to improve the performance of the organic light-emitting element, efforts have been made to develop an organic compound with a high refractive index and thin film stability that can improve the external luminous efficiency.

[0009] Prior art literature

[0010] Patent Literature

[0011] (Patent Document 1) Korean Patent Publication No. 10-2004-0098238 Summary of the invention

[0012] The object of the present invention is to provide an aromatic amine compound in which a 5-membered ring containing O, S, NR, Se, Te, CRR`, SiRR` or GeRR`, such as a furyl group, a thienyl group or a pyrrolyl group, is directly bonded or bonded to the nitrogen of the aromatic amine through a linker, which can increase the absorption wavelength in the ultraviolet region while having a wider band gap in the visible light region that is difficult to absorb and a high refractive index, thereby realizing a covering layer compound for an organic light-emitting element with high color purity, high efficiency and long service life, and an organic light-emitting element containing the above-mentioned covering layer compound.

[0013] In addition, the object of the present invention is to provide a compound for a covering layer and an organic light-emitting element that can optimize the film arrangement between molecules and thereby improve the refractive index by minimizing the volume characteristics of the terminal portion of the aromatic amine, and can also improve the stability by protecting the element from damage by external air and moisture, and because of a higher glass transition temperature (Tg) and a higher dew point temperature (Td), it can prevent recrystallization between molecules and maintain the stable state of the film when heat is generated during the driving process of the organic light-emitting element, thereby improving the external quantum efficiency and significantly improving the service life.

[0014] Next, the above-mentioned issues and additional issues will be described in detail.

[0015] As a means to solve the above problems,

[0016] The present invention provides a compound for a covering layer represented by the following Chemical Formula 1.

[0017] <Chemical Formula 1>

[0018]

[0019] In the above chemical formula 1,

[0020] X is O, S, NR, Se, Te, CRR`, SiRR` or GeRR`, wherein R and R` are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, and adjacent R and R` may or may not form a ring by combining with each other,

[0021] R1 to R4 are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, or substituted or unsubstituted C6-C50 aryl, R2 and R3 may or may not form a ring by combining with each other, and at least one of R1 to R4 is directly combined with L1,

[0022] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group,

[0023] L1 to L3 are each independently a direct bond, a substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group.

[0024] Next, the above-mentioned solution and additional solution will be described in detail.

[0025] According to an embodiment of the present invention, the compound for the covering layer is an aromatic amine compound in which a 5-membered ring containing O, S, NR, Se, Te, CRR`, SiRR` or GeRR`, such as a furyl group, a thienyl group or a pyrrolyl group, is directly bonded to the nitrogen of the aromatic amine or bonded through a connecting group. It can have a wider band gap in the visible light region that is difficult to absorb and a high refractive index while improving the absorption wavelength in the ultraviolet region, thereby realizing an organic light-emitting element with high color purity, high efficiency and long service life when it is suitable for a covering layer of an organic light-emitting element.

[0026] In addition, the present invention can optimize the film arrangement between molecules and thereby improve the refractive index by minimizing the volume characteristics of the terminal portion of the aromatic amine, and can also improve stability by protecting the element from external air and moisture. Moreover, because of its higher glass transition temperature (Tg) and higher dew point temperature (Td), it can prevent recrystallization between molecules and maintain the stability of the film when heat is generated during the driving process of the organic light-emitting element, thereby improving the external quantum efficiency and significantly improving the service life.

[0027] Next, the above-mentioned effects and additional effects will be described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cross-sectional view schematically showing the layer structure of an organic light-emitting element.

[0029] Figure 2 It is the result of measuring the absorption intensity in the wavelength range of 320nm to 480nm.

[0030]

Explanation of symbols

[0031] 100: Substrate

[0032] 200: Hole injection layer

[0033] 300: Hole transport layer

[0034] 400: Luminous layer

[0035] 500: Electron transport layer

[0036] 600: Electron injection layer

[0037] 1000: 1st electrode

[0038] 2000: The second electrode

[0039] 3000: Overlay DETAILED DESCRIPTION

[0040] Before describing the present invention in detail, it should be understood that the terms used in this specification are only used to describe specific embodiments and are not intended to limit the scope of the present invention, which shall only be limited by the scope of the appended claims. Unless otherwise expressly stated, all technical terms and scientific terms used in this specification have the same meanings as those commonly understood by people with general knowledge.

[0041] Throughout this specification and claims, unless expressly stated otherwise, terms such as comprise, comprises, and comprising merely indicate the inclusion of the stated item, step, or series of items and steps, and do not exclude any other item, step, or series of items or steps in advance.

[0042] Throughout the specification and claims, the term "aryl" may refer to, for example, phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorenyl, phenanthrenyl, triphenylene, phenylene, Benzotriphenylene, fluoranthene, benzofluorenyl, benzotriphenylene, benzo The term "heteroaryl" refers to a C5-50 aromatic hydrocarbon ring group having an aromatic ring such as an anthracene ring, a stilbene ring and a pyrenyl ring, and "heteroaryl" refers to a pyrrolyl, pyrazinyl, pyridyl, indolyl, isoindolyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothienyl, dibenzothienyl, quinolyl, isoquinolyl, quinoxalinyl, carbazolyl, phenanthridinyl, acridinyl, phenanthrolinyl, thienyl and a pyridine ring, a pyrazine ring, A C2-50 aromatic ring containing one or more hetero elements and composed of a heterocyclic group such as a pyrimidine ring, a pyridazine ring, a triazine ring, an indole ring, a quinoline ring, an acridine ring, a pyrrolidine ring, a dioxane ring, a piperidine ring, a morpholine ring, a piperazine ring, a carbazole ring, a furan ring, a thiophene ring, an oxazole ring, an oxadiazole ring, a benzofuran ring, a thiazole ring, a thiadiazole ring, a benzothiophene ring, a triazole ring, an imidazole ring, a benzimidazole ring, a pyran ring, or a dibenzofuran ring.

[0043] In addition, Ar in the chemical formula x (wherein x is an integer) unless otherwise clearly defined, represents a substituted or substituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, L x (wherein x is an integer) unless otherwise clearly defined, it represents a directly bonded, substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group, R x (wherein x is an integer) unless explicitly defined otherwise, represents 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.

[0044] Throughout the specification and claims, the term "substituted or unsubstituted" refers to a group consisting of deuterium, halogen, amino, cyano, nitrile, nitro, nitroso, sulfamoyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylsulfanyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1-C12 N The term "alkyl" may be substituted or unsubstituted with 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-alkylsulfamoyl, C2-C12 N,N-dialkylsulfamoyl, C3-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C2-C50 heteroaryl, but is not particularly limited thereto. In addition, throughout the specification of the present application, unless otherwise clearly stated, the same symbols have the same meaning.

[0045] In addition, unless otherwise explicitly stated to the contrary, the various embodiments of the present invention may be combined with certain other embodiments. Next, the embodiments of the present invention and their effects will be described.

[0046] The organic light-emitting element according to one embodiment of the present invention may be an organic light-emitting element including a covering layer. Specifically, it may be an organic light-emitting element including a first electrode, a second electrode, one or more organic layers between the first electrode and the second electrode, and a covering layer disposed outside one or more electrodes of the first electrode and the second electrode and containing the compound for covering layer of the present invention.

[0047] Specific examples of the compound for a covering layer of the present invention include a compound for a covering layer represented by the following Chemical Formula 1.

[0048] <Chemical Formula 1>

[0049]

[0050] In the above chemical formula 1,

[0051] X is O, S, NR, Se, Te, CRR`, SiRR` or GeRR`, wherein R and R` are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, and adjacent R and R` may or may not form a ring by combining with each other,

[0052] R1 to R4 are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, or substituted or unsubstituted C6-C50 aryl, R2 and R3 may or may not form a ring by combining with each other, and at least one of R1 to R4 is directly combined with L1,

[0053] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group,

[0054] L1 to L3 are each independently a direct bond, a substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group.

[0055] In the above content, the substituent when substituted may include 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 thiol, substituted or unsubstituted C6~C50 aryl, or substituted or unsubstituted C2~C50 heteroaryl.

[0056] In the compound for the covering layer of the present invention represented by the chemical formula 1 as described above, an aromatic amine compound in which a 5-membered ring containing O, S, NR, Se, Te, CRR', SiRR' or GeRR' is directly bonded or bonded to the nitrogen of the aromatic amine through a linker, such as a furanyl, thienyl or pyrrole group, can increase the absorption wavelength in the ultraviolet region while having a wide band gap and a high refractive index that are difficult to absorb in the visible light region, thereby realizing an organic light-emitting element with high color purity, high efficiency and long service life. In addition, by minimizing the volume characteristics of the terminal portion of the aromatic amine and optimizing the film arrangement between molecules and thereby improving the refractive index, the stability can also be improved by protecting the element from external air and moisture, and by forming a higher glass transition temperature (Tg) and a higher dew point temperature (Td), it is possible to prevent recrystallization between molecules and maintain the stable state of the film when heat is generated during the driving process of the organic light-emitting element, thereby realizing an organic light-emitting element with improved external quantum efficiency and significantly improved service life.

[0057] As a specific example compound of the compound for a covering layer of the present invention, the above Chemical Formula 1 may include a compound for a covering layer represented by the following Chemical Formula 2.

[0058] <Chemical Formula 2>

[0059]

[0060] In the above chemical formula 2,

[0061] The definitions of X, R1 to R4, L2, L3, Ar1 and Ar2 are the same as those in the above Chemical Formula 1.

[0062] R5 is each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl (wherein the carbon number of R5 satisfies the carbon number range defined in L1),

[0063] m is each independently an integer from 0 to 4,

[0064] l is an integer from 1 to 5.

[0065] In the cover layer compound of the present invention represented by Chemical Formula 2, a 5-membered ring is connected to nitrogen of an amine group via a linking group including one or more phenylene groups, thereby minimizing the absorption wavelength in a blue region and effectively improving the refractive index.

[0066] In addition, as a specific example compound of the compound for a covering layer of the present invention, the above Chemical Formula 1 may include a compound for a covering layer represented by the following Chemical Formula 3.

[0067] <Chemical formula 3>

[0068]

[0069] In the above chemical formula 3,

[0070] The definitions of X, R1 to R4, L2, L3, Ar1 and Ar2 are the same as those in the above Chemical Formula 1.

[0071] R5 is each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl (wherein the carbon number of R5 satisfies the carbon number range defined in L1),

[0072] m is each independently an integer from 0 to 4,

[0073] l is an integer from 1 to 5.

[0074] In the covering compound of the present invention represented by the above Chemical Formula 3, the 5-membered ring is connected to the nitrogen of the amine group through a linking group containing one or more 1,4-phenylene groups, so that the absorption wavelength in the ultraviolet region can be increased while having a high refractive index, thereby improving the stability when exposed to external ultraviolet rays.

[0075] In addition, in the above chemical formula 3, any one or both of the above L2 and L3 may include one or more phenylene groups, specifically one or more 1,4-phenylene groups, and more specifically both L2 and L3 may be 1,4-phenylene groups. In the above case, the absorption wavelength in the ultraviolet region can be increased while having a high refractive index, thereby further improving the stability when exposed to external ultraviolet rays.

[0076] In addition, as a specific example compound of the compound for a covering layer of the present invention, the above Chemical Formula 1 may include a compound for a covering layer represented by the following Chemical Formula 4.

[0077] <Chemical Formula 4>

[0078]

[0079] In the above chemical formula 4,

[0080] The definitions of X, R1, L2, L3, Ar1 and Ar2 are the same as those in the above chemical formula 1.

[0081] R5 is each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl (wherein the carbon number of R5 satisfies the carbon number range defined in L1),

[0082] m is each independently an integer from 0 to 4,

[0083] l is an integer from 1 to 5.

[0084] More specifically, in the above Chemical Formula 4, R1 may be hydrogen, tritium, phenyl or biphenyl.

[0085] In the coating compound of the present invention represented by Chemical Formula 4, the refractive index can be effectively improved even with a small molecular weight by minimizing the volume characteristics of the terminal portion of the 5-membered ring to prevent the refractive index from decreasing and forming a stable film through excellent film arrangement.

[0086] In addition, as a specific example compound of the compound for a covering layer of the present invention, the above Chemical Formula 1 may include a compound for a covering layer represented by the following Chemical Formula 5 or Chemical Formula 6.

[0087] <Chemical Formula 5>

[0088]

[0089] <Chemical Formula 6>

[0090]

[0091] In the above Chemical Formula 5 and Chemical Formula 6,

[0092] The definitions of X, R1 to R4, L1, L2, L3 and Ar2 are the same as those in the above Chemical Formula 1.

[0093] The definitions of X2 and X3 are independently the same as those of X in the above chemical formula 1,

[0094] R6 to R9 are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, or substituted or unsubstituted C6-C50 aryl, R7 and R8 may or may not form a ring by combining with each other, and at least one of R6 to R9 is directly combined with L2,

[0095] R10 to R13 are each independently hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thiol, or substituted or unsubstituted C6-C50 aryl, R11 and R12 may or may not form a ring by combining with each other, and at least one of R10 to R13 is directly combined with L3.

[0096] In the compound for a cover layer of the present invention represented by Chemical Formula 5 or Chemical Formula 6 as described above, two or more 5-membered rings are bonded to nitrogen of one amine group directly or through a linker, thereby achieving a high refractive index.

[0097] In any of the above Chemical Formulas 1 to 6, X and X2 may each independently be O (oxygen) or S (sulfur). The volume characteristics may be reduced by minimizing the bonding length of heteroatoms, thereby effectively improving the refractive index and improving the deposition temperature.

[0098] Specifically, X and X2 may be O (oxygen). In the above case, the deposition temperature can be effectively lowered by reducing the molecular weight while maintaining a high refractive index.

[0099] Alternatively, X and X2 may be S (sulfur), thereby having a higher refractive index and a higher glass transition temperature (Tg), which is conducive to forming a stable thin film.

[0100] In addition, in any of the above chemical formulas 1 to 6, the above R, R', R1 to R4 can each independently be any one of the group consisting of hydrogen, deuterium, methyl, methoxy, phenyl, biphenyl and combinations thereof. In the above case, the refractive index can be improved by minimizing the volume characteristics of the 5-membered ring and the substituents combined therewith.

[0101] Specifically, R and R' can each independently be hydrogen, methyl or phenyl, and R1 to R4 can each independently be hydrogen or phenyl.

[0102] In Chemical Formula 5, R6 to R9 may also be each independently any one of the group consisting of hydrogen, deuterium, methyl, methoxy, phenyl, biphenyl and combinations thereof, specifically hydrogen or phenyl. Thereby, the refractive index can be improved.

[0103] In addition, in the above Chemical Formulas 1 to 6, the intermediate linking groups L1, L2 and L3 can each independently be directly bonded, a phenyl group or a biphenyl group. Specifically, L1, L2 and L3 can be a phenyl group or a biphenyl group. When the 5-membered ring containing X, Ar1 and Ar2 are not directly bonded but bonded to nitrogen through a linking group as described above, the refractive index and the absorption intensity can be improved.

[0104] In addition, in any of the chemical formulas 1 to 6, Ar1 and Ar2 may each independently include phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, triphenylene, carbazolyl, furanyl, thienyl, benzoxazolyl, oxazolyl, dibenzothienyl, and any combination thereof, specifically, naphthyl, phenanthryl, furanyl, thienyl, benzoxazolyl, oxazolyl, or dibenzothienyl. In the above case, the volume characteristics can be minimized, and the film arrangement between molecules is excellent, and the refractive index can be high, and the absorption in the ultraviolet region can be improved.

[0105] In any of the above chemical formulas 1 to 5, at least one of -L2-Ar1 and -L3-Ar2 (-L3-Ar2 in chemical formula 5) may be any of the following chemical structural formulas A-1 to A-13 or a compound for a covering layer including any of the following chemical structural formulas A-1 to A-13. Specifically, at least one of -L2-Ar1 and -L3-Ar2 (-L3-Ar2 in chemical formula 5) may be selected from the following chemical structural formulas A-1 to A-13.

[0106]

[0107] In the above chemical structural formulas A-1 to A-13,

[0108] q is each independently an integer of 0 to 3, and * represents a bonding position to nitrogen (N) of the above Chemical Formulae 1 to 5.

[0109] As described above, since the coating compound of the present invention has any one or more structures of the chemical formulae A-1 to A-13, it can excellently achieve high refractive index, stability of intermolecular thin film arrangement, improvement of absorption intensity in the ultraviolet region, and minimization of absorption in the blue region.

[0110] Specifically, at least one of -L2-Ar1 and -L3-Ar2 can be selected from the chemical structural formulas A-2, A-3, A-5, A-6, A-7 to A-10, and A-13, and more specifically, both -L2-Ar1 and -L3-Ar2 can be selected from the chemical structural formulas A-2, A-3, A-5, A-6, A-7 to A-10, and A-13. This can achieve a higher refractive index, stability of the intermolecular film arrangement, improvement of the absorption intensity in the ultraviolet region, and minimization of the absorption in the blue region, and can effectively improve thermal stability due to a lower deposition temperature.

[0111]

[0112] The compound for a coating layer of the present invention may be any of the following compounds. The following compounds are merely illustrative for explaining the present invention, and the present invention is not limited thereto.

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151] One embodiment of the compound for a covering layer of the present invention can be synthesized by an amination reaction, and its general synthesis reaction formula is shown below.

[0152]

[0153] In another embodiment of the present invention, an organic light-emitting element is provided, which is an organic light-emitting element including a covering layer, wherein the covering layer contains the compound for the covering layer as described above.

[0154] Next, an organic light emitting element according to an embodiment of the present invention will be described in detail.

[0155] In one implementation example of the present invention, the organic light-emitting element may include a first electrode, a second electrode, one or more organic layers between the first electrode and the second electrode, and a covering layer, and the covering layer may be arranged on the outside of any one or more of the first electrode and the second electrode.

[0156] Specifically, the thickness of the above-mentioned covering layer can be 200 to Specifically, it can be 300 to

[0157] In addition, the refractive index of the above-mentioned covering layer at a wavelength of 450nm can be 2.25 or more, specifically 2.30 or more, more specifically 2.35 or more, and the attenuation coefficient at a wavelength of 450nm can be 0.1 or less, specifically 0.05 or less, more specifically 0.01 or less. In addition, the ultraviolet absorption intensity at a wavelength of 380nm can be 0.8 or more, specifically 0.9 or more.

[0158] Among them, the side adjacent to the organic layer between the first electrode and the second electrode is called the inner side, and the side not adjacent to the organic layer is called the outer side. That is, when the covering layer is arranged on the outer side of the first electrode, the first electrode will be between the covering layer and the organic layer, and when the covering layer is arranged on the outer side of the second electrode, the second electrode will be between the covering layer and the organic layer.

[0159] According to an implementation example of the present invention, one or more organic layers may be interposed between the first electrode and the second electrode of the organic light-emitting element, and a covering layer may be formed outside any one or more of the first electrode and the second electrode. That is, the covering layer may be formed on the outside of the first electrode and the outside of the second electrode at the same time, or may be formed only on the outside of the first electrode or the outside of the second electrode.

[0160] Furthermore, the above-mentioned covering layer may include the compound for a covering layer according to the present invention, and may include the compound for a covering layer according to the present invention alone, or include two or more or simultaneously include known compounds.

[0161] In addition, the organic layer may include a hole transport layer, a light emitting layer, and an electron transport layer which generally constitute a light emitting portion, but is not limited thereto.

[0162] Specifically, an organic light-emitting element according to an implementation example of the present invention may include one or more organic layers constituting a light-emitting portion 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 a first electrode (anode) and a second electrode (cathode).

[0163] Figure 1 The organic light emitting element according to an embodiment of the present invention is schematically illustrated in a cross-sectional view. Figure 1 The structure shown is manufactured.

[0164] like Figure 1 As shown, the organic light-emitting element can be stacked in the order of substrate 100, first electrode 1000, hole injection layer 200, hole transport layer 300, light-emitting layer 400, electron transport layer 500, electron injection layer 600, second electrode 2000 and covering layer 3000 from bottom to top.

[0165] The substrate 100 may be a substrate commonly used in an organic light-emitting element, and in particular, may be a transparent glass substrate or a flexible plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness.

[0166] The first electrode 1000 is used as a hole injection electrode for injecting holes into the organic light emitting element. The first electrode 1000 is made of a material with a work function as low as possible to achieve hole injection, and can be formed of transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO) and graphene.

[0167] The hole injection layer 200 can be formed by depositing a hole injection layer material on the upper portion of the first electrode 1000 by a method such as vacuum deposition, spin coating, casting, or Langmuir-Blodgett (LB) method. When the hole injection layer 200 is formed by vacuum deposition, the deposition conditions 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 the thermal properties. Generally, the deposition temperature can be 50 to 500°C, 10 -8 Up to 10 -3 Torr vacuum degree, 0.01 to The deposition rate and The layer thickness can be appropriately selected within the range of 100 to 5 μm. In addition, a charge generation layer can be additionally deposited on the surface of the hole injection layer 200 as needed. As the charge generation layer material, a general material can be used, for example, hexacyano-hexaazatriphenylene (HATCN) can be used.

[0168] Next, the hole transport layer 300 can be formed by depositing a hole transport layer material on the upper part of the hole injection layer 200 by a method such as vacuum deposition, spin coating, casting, Langmuir-Brockett (LB) method, etc. When the hole transport layer 300 is formed by the vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferred to select conditions that are almost the same as those for the formation of the hole injection layer 200. The hole transport layer 300 can be formed using known compounds. The hole transport layer 300 as described above can be more than one layer, and although in Figure 1 Although not shown in the figure, a light-emitting auxiliary layer may be additionally formed on the upper part of the hole transport layer 300 .

[0169] The light-emitting layer 400 can be formed by depositing the light-emitting layer material on the hole transport layer 300 or the light-emitting auxiliary layer by a method such as vacuum deposition, spin coating, casting, Langmuir-Brødt (LB) method, etc. When the light-emitting layer 400 is formed by the vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferred to select conditions within the same range as those for forming the hole injection layer 200. As the light-emitting layer material, a known compound can be used as a main agent or a dopant.

[0170] In addition, when phosphorescent dopants are used simultaneously in the light-emitting layer material, in order to prevent triplet excitons or holes from diffusing to the electron transport layer 500, a stacked hole blocking material (HBL) can be added to the upper part of the light-emitting layer 400 by vacuum deposition or spin coating. The hole blocking material used at this time is not particularly limited, and any known material can be selected for use. For example, oxadiazole derivatives or benzotriazole derivatives, o-phenanthroline derivatives or hole blocking materials described in Japanese Patent Laid-Open No. 11-329734 (A1) can be used, among which the most representative ones include Balq (bis (8-hydroxy-2-methylquinoline) - (4-phenylphenoxy) aluminum), phenanthroline (phenanthrolines) compounds (for example: UDC's BCP (bathocuproin)) and the like. The light-emitting layer 400 of the present invention as described above can include more than one layer or more than two layers of blue light-emitting layers.

[0171] The electron transport layer 500 is formed on the upper part of the light emitting layer 400 and can be formed by methods such as vacuum deposition, spin coating, casting, etc. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but it is generally preferred to select conditions that are almost the same as those for forming the hole injection layer 200.

[0172] The electron injection layer 600 may be formed by depositing an electron injection layer material on the electron transport layer 500 , and may be formed by a method such as vacuum deposition, spin coating, or casting.

[0173] The organic layers such as the hole injection layer 200 , the hole transport layer 300 , the light emitting layer 400 , and the electron transport layer 500 of the organic light emitting element can be manufactured using known materials.

[0174] The second electrode 2000 is used as an electron injection electrode and can be formed on the upper part of the electron injection layer 600 by vacuum deposition or spin coating. A variety of metals can be used as the material of the second electrode 2000. Specific examples include materials such as aluminum, gold, silver, magnesium, etc., but are not limited thereto.

[0175] The organic light-emitting element of the present invention can not only use the organic light-emitting element as described above including the covering 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 covering layer 3000, but can also use organic light-emitting elements of various structures, and can also add one or two intermediate layers as needed.

[0176] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted as required, and specifically can be 1 to 1000 nm, and more specifically can be 30 to 100 nm.

[0177] The cover layer 3000 may be formed on the outer side of the two side surfaces of the first electrode 1000 where the hole injection layer 200 is not formed. In addition, the cover layer 3000 may be formed on the outer side of the two side surfaces of the second electrode 2000 where the electron injection layer 600 is not formed, but the present invention is not limited thereto. The cover layer 3000 may be formed by a deposition process, and the thickness of the cover layer 3000 may be 100 to 1000 μm. More specifically, it can be 300 to By adjusting the thickness as described above, the problem of a decrease in transmittance of the cover layer 3000 can be prevented.

[0178] In addition, although Figure 1Although not shown in the figure, according to an 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 portion (outer surface) of the cover layer 3000, but the present invention is not limited thereto.

[0179] Next, an organic light emitting element including a cover layer according to an embodiment of the present invention will be described in detail with reference to manufacturing examples and embodiments. The following manufacturing examples and embodiments are only used to illustrate the present invention, and the scope of the present invention is not limited to the following manufacturing examples and embodiments.

[0180] Preparation Example 1: Synthesis of Compound 7

[0181]

[0182] In a round-bottom flask, 2.0 g of 2-(4-bromophenyl)-5-phenylfuran, 3.1 g of bis(4-(naphthalen-2-yl)phenyl)amine, 1.0 g of t-BuONa, 0.2 g of Pd2(dba)3, and 0.3 ml of (t-Bu)3P were dissolved in 100 ml of toluene and then refluxed with stirring. The reaction was confirmed by thin layer chromatography (TLC) and the reaction was terminated after adding water. The organic layer was extracted with dichloromethane (MC) and recrystallized after vacuum filtration to obtain 2.8 g of compound 7 (yield: 66%).

[0183] m / z: 639.26 (100.0%), 640.26 (52.3%), 641.26 (13.6%), 642.27 (2.2%)

[0184] Preparation Example 2: Synthesis of Compound 103

[0185]

[0186] Compound 103 was prepared in the same manner as in Preparation Example 1, except that 2-(4-bromophenyl)-5-phenylthiophene was used instead of 2-(4-bromophenyl)-5-phenylfuran (yield: 68%).

[0187] m / z: 655.23 (100.0%), 656.24 (52.3%), 657.24 (13.8%), 657.23 (4.7%), 658.23 (2.4%), 658.24 (2.4%), 656.23 (1.2%)

[0188] Preparation Example 3: Synthesis of Compound 112

[0189]

[0190] The same method as in Preparation Example 1 was used to synthesize Compound 112 (yield 65%), wherein 2-(4-bromophenyl)-5-phenylthiophene and bis(4-(phenanthren-9-yl)phenyl)amine were used instead of 2-(4-bromophenyl)-5-phenylfuran and bis(4-(naphthalen-2-yl)phenyl)amine.

[0191] m / z: 755.26 (100.0%), 756.27 (61.0%), 757.27 (19.0%), 757.26 (4.5%), 758.27 (3.7%), 758.26 (2.8%), 756.26 (1.2%)

[0192] Preparation Example 4: Synthesis of Compound 131

[0193]

[0194] The same method as in Preparation Example 1 was used to prepare Compound 131 (yield: 62%), wherein 2-(4-bromophenyl)-5-phenylthiophene and bis(4-(dibenzo[b,d]furan-4-yl)phenyl)amine were used instead of 2-(4-bromophenyl)-5-phenylfuran and bis(4-(naphthalen-2-yl)phenyl)amine.

[0195] m / z: 735.22 (100.0%), 736.23 (56.7%), 737.23 (16.6%), 737.22 (4.7%), 738.23 (3.2%), 738.22 (2.6%), 736.22 (1.2%)

[0196] Preparation Example 5: Synthesis of Compound 138

[0197]

[0198] The same method as in Preparation Example 1 was used to prepare Compound 138 (yield 64%), wherein 2-(4-bromophenyl)-5-phenylthiophene and 4-(dibenzo[b,d]thiophen-2-yl)-N-(4-(naphthalen-2-yl)phenyl)aniline were used instead of 2-(4-bromophenyl)-5-phenylfuran and bis(4-(naphthalen-2-yl)phenyl)amine.

[0199] m / z: 711.21 (100.0%), 712.21 (54.5%), 713.21 (15.4%), 713.20 (9.1%), 714.20 (5.0%), 714.22 (2.5%), 712.20 (2.0%), 715.21 (1.4%)

[0200] Preparation Example 6: Synthesis of Compound 409

[0201]

[0202] The same method as in Preparation Example 1 was used to synthesize Compound 409 (yield 60%), except that bis(4-(benzofuran-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine.

[0203] m / z: 619.21 (100.0%), 620.22 (48.0%), 621.22 (12.1%), 622.22 (2.0%)

[0204] Preparation Example 7: Synthesis of Compound 410

[0205]

[0206] The same method as in Preparation Example 1 was used to prepare Compound 410 (yield 61%), wherein bis(4-(benzo[b]thiophen-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine.

[0207] m / z: 651.17 (100.0%), 652.17 (49.6%), 653.18 (11.2%), 653.16 (9.0%), 654.17 (4.4%), 654.18 (2.0%), 653.17 (1.2%), 655.17 (1.1%)

[0208] Preparation Example 8: Synthesis of Compound 411

[0209]

[0210] The compound 411 was synthesized in the same manner as in Preparation Example 1, wherein bis(4-(benzo[d]oxazol-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine to give compound 411 (yield: 62%).

[0211] m / z: 621.21 (100.0%), 622.21 (45.9%), 623.21 (11.4%), 624.22 (1.5%), 622.20 (1.1%)

[0212] Preparation Example 9: Synthesis of Compound 415

[0213]

[0214] The same method as in Preparation Example 1 was used to synthesize Compound 415 (yield 60%), except that bis(4-(quinolin-3-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine.

[0215] m / z: 641.25 (100.0%), 642.25 (50.1%), 643.25 (12.9%), 644.26 (2.0%), 642.24 (1.1%)

[0216] Preparation Example 10: Synthesis of Compound 433

[0217]

[0218] The same method as in Preparation Example 1 was used to synthesize compound 433 (yield 56%), wherein bis(4-(benzofuran-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylthiophene were used instead of bis(4-(naphthalen-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylfuran to synthesize compound 433 (yield 56%).

[0219] m / z: 635.19 (100.0%), 636.20 (48.0%), 637.20 (11.7%), 637.19 (5.1%), 638.19 (2.2%), 638.20 (2.1%), 636.19 (1.2%)

[0220] Preparation Example 11: Synthesis of Compound 434

[0221]

[0222] The compound 434 was prepared in the same manner as in Preparation Example 1, wherein bis(4-(benzo[b]thiophen-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylthiophene were used instead of bis(4-(naphthalen-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylfuran to give compound 434 (yield 60%).

[0223] m / z: 667.15 (100.0%), 668.15 (50.3%), 669.14 (13.6%), 669.15 (12.4%), 670.15 (6.8%), 670.16 (1.7%), 671.15 (1.5%)

[0224] Preparation Example 12: Synthesis of Compound 435

[0225]

[0226] The compound 435 was prepared in the same manner as in Preparation Example 1, wherein bis(4-(benzo[d]oxazol-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylthiophene were used instead of bis(4-(naphthalen-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylfuran to give compound 435 (yield 63%).

[0227] m / z: 637.18 (100.0%), 638.19 (45.8%), 639.19 (11.0%), 639.18 (5.0%), 640.18 (2.1%), 638.18 (1.9%), 640.19 (1.8%)

[0228] Preparation Example 13: Synthesis of Compound 439

[0229]

[0230] The compound 439 was synthesized in the same manner as in Preparation Example 1, wherein bis(4-(quinolin-3-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylthiophene were used instead of bis(4-(naphthalen-2-yl)phenyl)amine and 2-(4-bromophenyl)-5-phenylfuran to give a compound 439 (yield 59%).

[0231] m / z: 657.22 (100.0%), 658.23 (50.1%), 659.23 (12.7%), 659.22 (5.1%), 660.22 (2.3%), 660.23 (2.2%), 658.22 (1.9%)

[0232] Manufacturing of organic light-emitting devices

[0233] According to Figure 1 The structure shown in the figure manufactures an organic light-emitting element. The organic light-emitting element is formed by stacking from bottom to top in the order of substrate 100, anode (hole injection electrode 1000), hole injection layer 200, hole transport layer 300, light-emitting layer 400, electron transport layer 500, electron injection layer 600, cathode (electron injection electrode 2000), and cover layer 3000.

[0234] The compounds used in the organic layer located inside the electrode of the organic light-emitting element of the present invention are shown in Table 1 below.

[0235]

Table 1

[0236]

[0237] Example 1

[0238] A film is formed on the indium tin oxide (ITO) substrate on which the reflective layer containing Ag is formed as a hole injection layer. HI01 HATCN and as a hole transport layer HT01 is then used as the light-emitting layer. Next, a film was formed as an electron transport layer. ET01:Liq (1:1) after deposition Next, MgAg was deposited to a thickness of 15 nm, and then the compound prepared in Preparation Example 1 was deposited as a cover layer on the cathode. The organic light emitting element was manufactured by encapsulating the above elements in a glove box.

[0239] Example 2 to Example 5

[0240] The same method as in Example 1 was used to produce organic light-emitting devices by forming a cover layer using the compounds produced in Production Examples 2 to 5.

[0241] Comparative Examples 1 to 4

[0242] The same method as in Example 1 was used to produce an organic light-emitting element, wherein a cover layer was formed using Comparative Compounds 1 (Ref. 1) to 4 (Ref. 4) shown in Table 2 below.

[0243]

Table 2

[0244]

[0245] <Test Example 1> Performance Evaluation of Organic Light Emitting Element

[0246] By applying voltage to a Keithley 2400 source measurement unit to inject electrons and holes and using a Konica Minolta spectroradiometer (CS-2000) to measure the brightness of the emitted light, the performance of the organic light-emitting elements of Examples 1 to 5 and Comparative Examples 1 to 4, namely, the current density and brightness relative to the applied voltage, were evaluated under atmospheric pressure conditions. The results are shown in Table 3.

[0247]

Table 3

[0248] Classification Op.V <![CDATA[mA / cm 2 ]]> Cd / A CIEx CIE LT97 Example 1 3.49 10 7.69 0.139 0.043 175 Example 2 3.50 10 7.72 0.140 0.043 178 Example 3 3.49 10 7.76 0.140 0.043 184 Example 4 3.50 10 7.57 0.139 0.044 163 Example 5 3.50 10 7.61 0.139 0.044 165 Comparative Example 1 3.50 10 6.03 0.133 0.055 72 Comparative Example 2 3.50 10 6.65 0.130 0.051 118 Comparative Example 3 3.51 10 5.72 0.125 0.078 105 Comparative Example 4 3.50 10 6.20 0.133 0.054 98

[0249] The compound for the covering layer of the present invention is a structure in which a 5-membered ring such as furan or thiophene is bonded to the nitrogen of an amine group. Compared with Comparative Examples 1 to 3 containing two amine groups, it can have a high refractive index by minimizing the volume characteristics, and can also effectively improve the efficiency and service life of the organic light-emitting element by improving the absorption wavelength in the ultraviolet region. In addition, in the case of having a 5-membered ring as an intermediate connecting group in the two amine groups as described in Comparative Examples 2 and 3, it can be found that unlike the present invention, the efficiency and color purity will decrease due to absorption in the visible light region. In addition, the compound for the covering layer of the present invention is a structure in which a heteroaryl group is not included as a substituent of the 5-membered ring. Compared with Comparative Example 4 including a substituted heteroaryl group in the 5-membered ring, the volume characteristics of the terminal part of the condensed ring can be minimized to prevent the decrease of the refractive index and form a stable film through excellent film arrangement, so that even with a small molecular weight, the refractive index can be effectively improved and an organic light-emitting element with high color purity, high efficiency and long service life can be realized.

[0250] <Test Example 2> Evaluation of Refractive Index

[0251] Compounds 7 and 103 of the present invention and comparative compounds 1 (Ref. 1) to 4 (Ref. 4) in Table 2 were used to form a 30 nm thick deposited film on a silicon substrate using a vacuum deposition device, and then the refractive index and attenuation coefficient at 450 nm were measured using an ellipsometer (JA Woollam Co. Inc, M-2000X). The results are shown in Table 4 below.

[0252]

Table 4

[0253]

[0254] As recorded in the above Table 4, it can be confirmed that the compound for covering layer of the present invention exhibits a high refractive index of 2.25 or more, specifically 2.30 or more, and more specifically 2.35 or more, while the attenuation coefficient at 450nm is less than 0.1, specifically less than 0.05, and more specifically less than 0.01.

[0255] This is because the coating layer compound of the present invention includes one amine group bonded to a 5-membered ring compared to Comparative Compounds 1 (Ref. 1) to 3 (Ref. 3), and does not include a heteroaryl group as a substituent of the 5-membered ring compared to Comparative Compound 4 (Ref. 4).

[0256] Furthermore, the compound for a covering layer of the present invention has a high refractive index and increases the absorption wavelength in the ultraviolet region as shown in the results of Experimental Example 3 below, thereby effectively improving the efficiency and service life of the organic light emitting element.

[0257] <Test Example 3> Evaluation of absorption intensity in the ultraviolet region

[0258] In the ultraviolet region, the coating layer compound 7 and compound 103 of the present invention and the comparative compound 1 (Ref. 1) in Table 2 were used to form a 30 nm thick deposited film on a silicon substrate using a vacuum deposition device, and then the absorption wavelength in the range of 320 nm to 480 nm was measured using an ellipsometer device (JA Woollam Co. Inc, M-2000X). The results are as follows: Figure 2 In the ultraviolet absorption region of 380 nm, the absorption intensities of the coating compound 7 and the compound 103 of the present invention are 0.8 or more, specifically 0.9 or more, and it can be confirmed that the absorption intensities are increased by 50% or more compared with the comparative compound 1 (Ref. 1).

Claims

1. A covering layer comprising a compound for a covering layer represented by Chemical Formula 1, characterized in that: Chemical formula 1 In the above chemical formula 1, X is O or S, R4 is directly connected to L1, R2 to R3 are hydrogen or deuterium, R1 is phenyl, Ar1 and Ar2 are each independently any one of phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, triphenylene, carbazolyl, benzoxazolyl, dibenzofuranyl, dibenzothiophenyl, benzofuranyl, benzothiophenyl, and quinolyl, L1 to L3 are each independently a directly bonded, substituted or unsubstituted C6-C50 arylene group.

2. The covering layer according to claim 1, characterized in that: The above chemical formula 1 is a compound for a covering layer represented by the following chemical formula 2: Chemical formula 2 In the above chemical formula 2, The definitions of X, R1 to R4, L2, L3, Ar1 and Ar2 are the same as those in the above Chemical Formula 1. R5 are each independently hydrogen or deuterium, m is each independently an integer from 0 to 4, l is an integer from 1 to 5.

3. The covering layer according to claim 1, characterized in that: The chemical formula 1 is a compound for a covering layer represented by the following chemical formula 3: Chemical formula 3 In the above chemical formula 3, The definitions of X, R1 to R4, L2, L3, Ar1 and Ar2 are the same as those in the above Chemical Formula 1. R5 are each independently hydrogen or deuterium, m is each independently an integer from 0 to 4, l is an integer from 1 to 5.

4. The covering layer according to claim 3, characterized in that: Either one or both of L2 and L3 are 1,4-phenylene groups.

5. The covering layer according to claim 1, characterized in that: The chemical formula 1 is a compound for a covering layer represented by the following chemical formula 4: Chemical formula 4 In the above chemical formula 4, The definitions of X, R1, L2, L3, Ar1 and Ar2 are the same as those in the above chemical formula 1. R5 are each independently hydrogen or deuterium, m is each independently an integer from 0 to 4, l is an integer from 1 to 5.

6. The covering layer according to claim 1, characterized in that: Any one or more of the above-mentioned -L2-Ar 1 and -L 3-Ar 2 include any one of the following chemical structural formulas A-1 to A-13 or any one of the following chemical structural formulas A-1 to A-13: In the above chemical structural formulas A-1 to A-13, q is each independently an integer of 0 to 3, and * represents a bonding position to nitrogen (N) of the above Chemical Formulae 1 to 5.

7. The covering layer according to claim 1, characterized in that: The compound for the coating layer is any one of the following compounds, 8. An organic light emitting element, characterized in that: The covering layer comprises the covering layer as claimed in any one of claims 1 to 7.

9. The organic light emitting device according to claim 8, characterized in that: The organic light emitting element comprises: a first electrode and a second electrode; and, One or more organic layers are disposed inside the first electrode and the second electrode; The cover layer is arranged outside at least one of the first electrode and the second electrode.

10. The organic light emitting element according to claim 8, characterized in that: The thickness of the above-mentioned covering layer is 200 to 11. The organic light emitting device according to claim 8, characterized in that: The cover layer has a refractive index of 2.25 or more at a wavelength of 450 nm.

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