Novel compound for capping layer and organic light-emitting element comprising same

Abstract

The present invention provides a compound for a capping layer represented by the following Chemical Formula 1 and an organic light-emitting element comprising the same. Lt; chemical formula 1gt; # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a compound for a cover layer and an organic light-emitting element comprising the same. 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 luminescent material 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 a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer and a cathode are sequentially formed on the anode, wherein 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 the cathode, holes injected from the anode move to the light-emitting layer via the hole transport layer, and electrons injected from the cathode move to the light-emitting layer via the electron transport layer. The holes and 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 an organic layer such as a hole transport layer, a light-emitting layer, and an electron transport layer between the first electrode and the second electrode. The internal luminescence efficiency of fluorescence is theoretically 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 light extraction rate, various organic compounds with a refractive index of 1.7 or more for preventing the light irradiated to the outside from being lost due to total reflection are applied to the covering layer, and in order to improve the performance of the organic light-emitting element and increase the external luminous efficiency, efforts are being made to develop organic compounds with a high refractive index and thin film stability. Summary of the invention

[0009] The object of the present invention is to provide a compound for a covering layer and an organic light-emitting element containing the same. The compound for the covering layer has an aromatic amine structure with an electron-withdrawing connecting group such as a (pseudo) carbonyl group, thereby having a wide band gap with low light absorption in the visible light region, maintaining a high refractive index, and at the same time increasing the absorption wavelength in the ultraviolet region. Therefore, when the covering layer is introduced, an organic light-emitting element with high color purity, high efficiency and long life can be formed.

[0010] Another object of the present invention is to provide a covering layer compound having excellent intermolecular thin film alignment and capable of ensuring a higher refractive index by containing a (pseudo) carbonyl group having a lone pair of electrons, and an organic light-emitting element including the same.

[0011] In addition, the object of the present invention is to provide a compound for a covering layer and an organic light-emitting element containing the same, wherein the compound for the covering layer can not only improve the stability to external air and moisture, but also effectively prevent intermolecular recrystallization by having high Tg and high Td, and can maintain a stable thin film without being affected by the heat generated when the organic light-emitting element is driven, thereby being more effective in increasing the external quantum efficiency and improving the lifespan.

[0012] Next, the above-mentioned subjects and additional subjects will be described in detail.

[0013] In order to solve the above-mentioned problems, in one embodiment of the present invention,

[0014] Provided is a compound for a covering layer represented by the following chemical formula 1:

[0015] <Chemical Formula 1>

[0016]

[0017] In the chemical formula 1,

[0018] Ar1 and Ar2 are each independently a substituted or unsubstituted C5-C50 aryl group, a substituted or unsubstituted C2-C50 heteroaryl group, or RC(=X)-*,

[0019] X is each independently O, S, Se, Te or NR,

[0020] L is a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof,

[0021] L1 and L2 are each independently a direct bond, a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof,

[0022] 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 C0-C30 silyl, substituted or unsubstituted C2-C30 dialkylamino, substituted or unsubstituted C3-C50 cycloalkyl, substituted or unsubstituted C1-C50 heterocycloalkyl, substituted or unsubstituted C3-C50 cycloalkenyl, substituted or unsubstituted C2-C50 heterocycloalkenyl, substituted or unsubstituted C5-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl,

[0023] “*” represents the binding position.

[0024] Furthermore, in one embodiment of the present invention,

[0025] Provided is an organic light-emitting element containing the compound for a covering layer as described above.

[0026] The compound for the covering layer according to one embodiment of the present invention is a compound having an aromatic amine structure with an electron-withdrawing connecting group such as a (pseudo) carbonyl group, having a wide bandgap with low light absorption in the visible light region, and increasing the absorption wavelength in the ultraviolet region while maintaining a high refractive index. Therefore, when used in a covering layer, an organic light-emitting element with high color purity, high efficiency and long life can be realized.

[0027] Furthermore, the compound for a covering layer according to an embodiment of the present invention has excellent intermolecular thin film alignment and a higher refractive index by including a (pseudo) carbonyl group having a lone pair of electrons.

[0028] In addition, the compound for the covering layer according to one embodiment of the present invention can not only improve the stability to external air and moisture, but also effectively prevent intermolecular recrystallization by having high Tg and high Td, and maintain a stable film from being affected by the heat generated when driving the organic light-emitting element. Therefore, it can be more effective in increasing the external quantum efficiency and improving the lifespan.

[0029] Next, the effects described above and additional effects will be described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0031] Figure 2 FIG. 4 is a graph showing the measured absorption intensity of a compound according to an example of the present invention and a comparative compound in the wavelength range of 360 nm to 500 nm.

[0032]

Explanation of symbols

[0033] 100: Substrate

[0034] 200: Hole injection layer

[0035] 300: Hole transport layer

[0036] 400: Luminous layer

[0037] 500: Electron transport layer

[0038] 600: Electron injection layer

[0039] 1000: First electrode

[0040] 2000: Second Electrode

[0041] 3000: Overlay DETAILED DESCRIPTION

[0042] 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 clearly stated, the meanings of all technical terms and scientific terms used in this specification are the same as those commonly understood by people with general knowledge.

[0043] Throughout this specification and claims, unless expressly stated otherwise, the terms "comprise", "comprises" and "comprising" merely indicate the inclusion of the stated item, step or series of items and steps, and do not indicate the prior exclusion of any other item, step or series of items or steps.

[0044] Throughout the specification and claims, the term "aryl" refers to phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorenyl, phenanthrenyl, triphenylene, phenylene, Benzotriphenylene, fluoranthene, benzofluorenyl, benzotriphenylene, benzo The term "heteroaryl" refers to a C5-C50 aromatic hydrocarbon ring containing an aromatic ring such as a pyrrolyl, pyrazinyl, pyridyl, indolyl, isoindolyl, furyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophenyl, dibenzothiophenyl, quinolyl, isoquinolyl, quinoxalinyl, carbazolyl, phenanthridinyl, acridinyl, phenanthrolinyl, thienyl, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, indole ring, quinoline ring, acridinium ring, pyrrolidine ring, dibenzothiophenyl ring, Alkane ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, Azole ring, The heterocyclic group composed of a oxadiazole ring, a benzofuran ring, a thiazole ring, a thiadiazole ring, a benzothiophene ring, a benzotriazole ring, an imidazole ring, a benzimidazole ring, a pyran ring, a dibenzofuran ring or the like is a C2-C50 aromatic ring containing at least one heteroelement.

[0045] In addition, the term "arylene" means that the hydrogen in the above aryl group is replaced by a direct bond to become a divalent substituent, and the specific examples are not limited as long as the above aryl structure becomes a divalent substituent. Similarly, the term "heteroarylene" means that the hydrogen in the above heteroaryl group is replaced by a direct bond to become a divalent substituent, and the specific examples are not limited as long as the above heteroaryl structure becomes a divalent substituent.

[0046] 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.

[0047] Throughout the specification and claims, the term "substituted or unsubstituted" may refer to a group consisting of deuterium, halogen, amino, cyano, nitrile, nitro, nitroso, sulfamoyl, isothiocyanate, thiocyanate, carboxyl, carbonyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylsulfanyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, The alkyl group may be substituted or unsubstituted with one or more groups selected from the group consisting of C1-C12 N-alkylamino, C2-C20 N,N-dialkylamino, substituted or unsubstituted C1-C30 thiol, C1-C6 N-alkylsulfamoyl, C2-C12 N,N-dialkylsulfamoyl, C0-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C3-C50 heteroaryl. In addition, throughout the specification of the present application, unless otherwise explicitly stated, the same symbols may have the same meaning.

[0048] On the other hand, in the present specification, matters described with the above-defined terms such as "aryl", "heteroaryl", "arylene", "heteroarylene" and "substituent" include the above-listed examples and combinations thereof, and therefore, these terms may be replaced by the above-listed examples and combinations thereof or be subsequently modified.

[0049] In addition, when a range such as "C2 to C50" or "0 to 7" is described in this specification, even if there is no special description, it can be reduced to various ranges within the described range and is deemed to be described in this specification. As an example, C2 to C50 is deemed to be described together with C2 to C50, and various reduced ranges such as C5 to C50, C6 to C30, C6 to C20, C6 to C15, C6 to C10, and C12 to C30. Therefore, the description of the numerical range in this specification may be reduced and revised in the future.

[0050] On the other hand, unless otherwise explicitly stated to the contrary, the 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.

[0051] 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, the organic light-emitting element according to one embodiment of the present invention 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 disposed outside one or more electrodes of the first electrode and the second electrode and containing the compound for the covering layer of the present invention.

[0052] As a specific example of the compound for a covering layer of the present invention, a compound for a covering layer represented by the following Chemical Formula 1 may be included.

[0053] <Chemical Formula 1>

[0054]

[0055] In the chemical formula 1,

[0056] Ar1 and Ar2 are each independently a substituted or unsubstituted C5-C50 aryl group, a substituted or unsubstituted C2-C50 heteroaryl group, or RC(=X)-*,

[0057] X is each independently O, S, Se, Te or NR,

[0058] L is a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof,

[0059] L1 and L2 are each independently a direct bond, a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof,

[0060] 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 C0-C30 silyl, substituted or unsubstituted C2-C30 dialkylamino, substituted or unsubstituted C3-C50 cycloalkyl, substituted or unsubstituted C1-C50 heterocycloalkyl, substituted or unsubstituted C3-C50 cycloalkenyl, substituted or unsubstituted C2-C50 heterocycloalkenyl, substituted or unsubstituted C5-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl,

[0061] “*” represents the binding position.

[0062] On the other hand, when at least one of Ar1 and Ar2 is an aryl group, each of them independently can be a substituted or unsubstituted C6 to C22 aryl group. Specifically, it can be a substituted or unsubstituted C10 to C22 aryl group. In addition, when at least one of Ar1 and Ar2 is a heteroaryl group, each of them independently can be a substituted or unsubstituted C2 to C22 heteroaryl group.

[0063] On the other hand, when at least one of L, L1 and L2 is an arylene group, each independently may be a substituted or unsubstituted C6 to C18 arylene group. In addition, when at least one of L, L1 and L2 is a heteroarylene group, each independently may be a substituted or unsubstituted C2 to C22 heteroarylene group.

[0064] On the other hand, if Ar1 is a phenyl group, L1 may not be a direct bond. In addition, if Ar2 is a phenyl group, L2 may not be a direct bond. If both Ar1 and Ar2 are phenyl groups, both L1 and L2 may not be a direct bond. Thus, the refractive index can be further increased.

[0065] On the other hand, in the chemical formula 1, the substituents when substituted include deuterium, halogen, amino, cyano, nitrile, nitro, nitroso, sulfamoyl, isothiocyanate, thiocyanate, carboxyl, carbonyl, C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylsulfanyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 The substituents include alkyl, C1-C12 N-alkylamino, C2-C20 N,N-dialkylamino, substituted or unsubstituted C1-C30 mercapto, C1-C6 N-alkylsulfamoyl, C2-C12 N,N-dialkylsulfamoyl, C0-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl and C3-C50 heteroaryl, etc. More specific substituents include deuterium, halogen, nitrile, C1-C10 alkyl, C1-C10 alkoxy, C1-C10 alkylthio, C1-C10 fluoroalkyl in which hydrogen is replaced by fluorine, C6-C20 aryl and C3-C20 heteroaryl.

[0066] As a specific example compound of the compound for a covering layer of the present invention, the chemical formula 1 may include a compound for a covering layer represented by the following chemical formula 2.

[0067] <Chemical Formula 2>

[0068]

[0069] In the chemical formula 2,

[0070] The definitions of the same symbols as those in Chemical Formula 1 are the same as those in Chemical Formula 1.

[0071] R1 is independently the same as defined above for R,

[0072] l is an integer from 1 to 4.

[0073] The compound for a covering layer of the present invention represented by the chemical formula 2 has a linear bonding structure of a core, and thus has excellent thin film alignment, and is effective in improving the refractive index.

[0074] As a specific example compound of the compound for a covering layer of the present invention, the chemical formula 1 may include a compound for a covering layer represented by the following chemical formula 3 or chemical formula 4.

[0075] <Chemical formula 3>

[0076]

[0077] <Chemical Formula 4>

[0078]

[0079] In the chemical formula 3 and the chemical formula 4,

[0080] The definitions of the same symbols as those in Chemical Formula 1 are the same as those in Chemical Formula 1.

[0081] R1 to R3 are each independently the same as defined above for R,

[0082] l, m and n are each independently an integer of 1 to 4.

[0083] Specifically, l, m and n may be 1 to 2 each independently.

[0084] The compound for a covering layer of the present invention represented by Chemical Formula 3 or Chemical Formula 4 has two or more (pseudo) carbonyl groups, thereby having a higher refractive index and improving the absorption wavelength intensity in the ultraviolet region.

[0085] As a specific example compound of the compound for a covering layer of the present invention, the chemical formula 1 may include a compound for a covering layer represented by the following chemical formula 5.

[0086] <Chemical Formula 5>

[0087]

[0088] In the chemical formula 5,

[0089] Definitions of the same symbols as those in Chemical Formula 1 are the same as those in Chemical Formula 1.

[0090] The compound for a capping layer of the present invention represented by Chemical Formula 5 can minimize the bulky characteristics of the carbonyl core and control the π conjugation of the amine bonding site, thereby minimizing the absorption wavelength in the blue region while improving the refractive index.

[0091] In addition, in the chemical formula 1 to the chemical formula 5,

[0092] Specifically, the R can be independently selected from the group consisting of substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C5-C18 aryl, or a combination thereof. Therefore, the film arrangement of molecules becomes excellent, the refractive index is improved, and the absorption in the blue region can be minimized.

[0093] Specifically, the R can be independently selected from the group consisting of a methyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a combination thereof. Therefore, the bulky property can be minimized to maintain a high refractive index, and the deposition temperature can be further reduced by reducing the molecular weight. When the phenyl and naphthyl groups are substituted, the substituents can be independently selected from deuterium, a nitrile group, a C1-C10 alkyl group, and a phenyl group.

[0094] In addition, in the chemical formula 1 to the chemical formula 5,

[0095] One or more of Ar1 and Ar2 can be independently selected from the group consisting of a substituted or unsubstituted fused aryl group having four or fewer rings and a substituted or unsubstituted fused heteroaryl group having four or fewer rings. By using a fused ring group having the property of minimizing bulkiness as a substituent, the intermolecular film arrangement is excellent, the refractive index is high, and the absorption intensity in the ultraviolet region can be increased.

[0096] In addition, in the chemical formulas 1 to 5, when one or more of Ar1 and Ar2 are substituted or unsubstituted C2-C50 heteroaryl groups, each independently may have 1 to 3 of O, S and N as hetero elements. Therefore, it can have a high refractive index while minimizing absorption in the blue region.

[0097] Meanwhile, one or more of Ar1 and Ar2 may be independently a substituted or unsubstituted C10-C50 aryl group, thereby further improving the refractive index.

[0098] In the chemical formulae 1 to 5, Ar1 to Ar2 can be independently selected from phenyl, naphthyl, quinolyl, isoquinolyl, benzofuranyl, benzothiophene, benzo In addition, Ar1 to Ar2 are each independently phenanthryl, triphenylene, indolyl, indenyl, benzimidazolyl, phenyl-substituted furanyl, phenyl-substituted thienyl, phenyl-substituted pyrrolyl, oxadiazolyl, triazolyl, fluorenyl, carbazolyl, benzocarbazolyl, benzofluorenyl, dibenzofuranyl, dibenzothiophenyl and the like.

[0099] In addition, in the chemical formula 1, the L may be a phenylene group, a biphenylene group, a pyridylene group, or a combination thereof, and in the chemical formulas 1 to 3 and 5, the L1 and L2 may each independently be a direct bond, a phenylene group, a biphenylene group, a pyridylene group, or a combination thereof. In this case, the refractive index may be further increased and the deposition temperature may be reduced, which has a favorable effect in the manufacturing process.

[0100] In addition, in the chemical formula 1 to the chemical formula 5,

[0101] Specifically, one or more of -L1-Ar1 and -L2-Ar2 can be independently any one of the following chemical structural formulas A-1 to A-37, or can include any one of the following chemical structural formulas A-1 to A-37:

[0102]

[0103]

[0104]

[0105] In the chemical structural formulas A-1 to A-37,

[0106] q and w are each independently an integer from 0 to 3,

[0107] R4 is each independently deuterium, halogen, nitrile, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, or C1-C3 fluoroalkyl in which hydrogen is replaced by fluorine, and "*" represents a bonding position.

[0108] As described above, the cover compound of the present invention has any one or more of the chemical structural formulas A-1 to A-37, thereby excellently achieving high refractive index, stability of intermolecular thin film arrangement, increased absorption intensity in the ultraviolet region, and minimal absorption in the blue region.

[0109] Furthermore, the compound for a capping layer represented by Chemical Formula 1 may have a high refractive index of 2.30 or more, specifically 2.40 or more, when the refractive index at a wavelength of 450 nm is measured after the deposited film is deposited at a thickness of 30 nm to 120 nm.

[0110] In addition, the compound of the chemical formula 1 may be a compound for a covering layer represented by any one of the following compounds: The following compounds are merely examples for explaining the present invention, and the present invention is not limited thereby.

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[0194] One example of the compound of the present invention can be synthesized by the following schematic reaction formula.

[0195] <Reaction formula 1>

[0196]

[0197] In another embodiment of the present invention, a covering layer for an organic light-emitting element is provided, comprising the above-mentioned compound for a covering layer.

[0198] 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.

[0199] Next, an organic light emitting element according to an embodiment of the present invention will be described in detail.

[0200] 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.

[0201] Specifically, the side of the first electrode or the second electrode 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.

[0202] In addition, in an implementation example of the present invention, one or more organic layers may be interposed between the inner sides of 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 outer sides of the first electrode and the second electrode at the same time, or may be formed only on the outer sides of the first electrode or the second electrode.

[0203] In this case, the coating layer may contain the coating compound according to the present invention, and may contain the coating compound according to the present invention alone or in combination of two or more thereof, or may contain known compounds simultaneously.

[0204] The thickness of the covering layer can be to

[0205] On the other hand, the covering layer may adopt a composite covering layer structure formed by stacking a first covering layer with a relatively low refractive index and a second covering layer with a higher refractive index than the first covering layer. In the case as described above, the compound for the covering layer according to the present invention may be contained in the second covering layer. The stacking order of the first covering layer and the second covering layer is not subject to special restrictions. The first covering layer may be arranged on the outside of the second covering layer, and conversely, the second covering layer may be arranged on the outside of the first covering layer. As a specific example, the second covering layer may be between the first covering layer and the first electrode or the second electrode. Specifically, the second covering layer may be a structure in contact with the first covering layer and the first electrode or the first covering layer and the second electrode.

[0206] In addition, a multilayer structure formed by stacking a plurality of first covering layers and a plurality of second covering layers may also be adopted. In the above case, the first covering layers and the second covering layers may be stacked alternately, and the stacking order is not limited to the above order. The first covering layer may be arranged on the outside of the second covering layer, and conversely, the second covering layer may be arranged on the outside of the first covering layer.

[0207] In addition, to In any thickness range of , the refractive index of the first covering layer at a wavelength of 450 nm may be 1.55 or less, specifically, 1.53 or less, and more specifically, 1.51 or less. to In any thickness within the thickness range of , the refractive index of the second covering layer at a wavelength of 450 nm may be greater than 2.30, specifically, greater than 2.40.

[0208] The total thickness of the first covering layer may be to The total thickness of the second covering layer may be within the range of to within the range.

[0209] On the other hand, the refractive index of the cover layer may also be in a gradient form. Regarding the refractive index gradient, the refractive index may gradually decrease as it approaches the outer side, or the refractive index may gradually increase as it approaches the outer side. To this end, the cover layer may be formed by gradually changing the concentration of the cover layer compound according to the present invention, thereby realizing a refractive index gradient in the cover layer.

[0210] On the other hand, 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 the present invention is not limited thereto.

[0211] 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). Optionally, a hole blocking layer (HBL, not shown) or an electron transport auxiliary layer may be included between the light-emitting layer (EML) and the electron transport layer (ETL), and an electron blocking layer (EBL, not shown) or a light-emitting auxiliary layer may be included between the hole transport layer (HTL) and the light-emitting layer (EML).

[0212] 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.

[0213] like Figure 1 As shown, the organic light-emitting element can be a structure in which a substrate 100, a first electrode 1000, a hole injection layer 200, a hole transport layer 300, a light-emitting layer 400, an electron transport layer 500, an electron injection layer 600, a second electrode 2000 and a covering layer 3000 are stacked in sequence from bottom to top. Among them, although not shown in the figure, the covering layer 3000 can be a covering layer as described above or a structure in which a first covering layer and a second covering layer are stacked. In addition, it can also be a structure in which a third covering layer having a refractive index different from that of the first covering layer and the second covering layer is additionally stacked, and is not subject to special limitations. In addition, the refractive index of the covering layer can also be in a gradient form. Regarding the gradient of the refractive index, the refractive index can gradually decrease when approaching the outside, or the refractive index can gradually increase when approaching the outside.

[0214] The substrate 100 may be a substrate commonly used in organic light-emitting elements, and in particular, may be a transparent glass substrate or a flexible plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, handling convenience, and waterproofness.

[0215] In addition, 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 using transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO) and graphene.

[0216] 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 by a method such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, etc. When the hole injection layer 200 is formed by vacuum deposition, the deposition conditions will vary depending on the compound used as the material of the hole injection layer 200, the required 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 is 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.

[0217] In addition, 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-Brødt (LB) method, etc. When the hole transport layer 300 is formed by the vacuum deposition method, its 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 a known compound. 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 .

[0218] At the same time, the light-emitting layer 400 can be formed by depositing the light-emitting layer material on the upper part of the hole transport layer 300 or the light-emitting auxiliary layer by using methods such as vacuum deposition, spin coating, casting, Langmuir-Brockett (LB) method, etc. When the light-emitting layer 400 is formed by the vacuum deposition method, its deposition conditions will vary depending on the compound used, but it is usually appropriate to select it within a range of conditions that are almost the same as those for the formation of the hole injection layer 200. As the light-emitting layer material, well-known compounds can be used as a main agent or a dopant. The dopant is not limited, and phosphorescent or fluorescent dopants can be used simultaneously to form the light-emitting layer. As an example, BD142 (N6, N12-bis (3, 4-dimethylphenyl) -N6, N12-dipodyl) can be used as a fluorescent dopant. -6,12-diamine), and as the phosphorescent dopant, a green phosphorescent dopant, namely Ir(ppy)3 (tri(2-phenylpyridine)iridium), a blue fluorescent dopant, namely F2Irpic (bis[4,6-difluorophenyl)-pyridyl-N,C2']picolinic acid iridium (III)), and a red phosphorescent dopant, namely RD61 of UDC, etc., can be used for vacuum deposition (doping) together. The doping concentration of the dopant is not particularly limited, and it is appropriate to dope 0.01 to 15 parts by weight of the dopant relative to 100 parts by weight of the main agent. When the content of the dopant is less than 0.01 parts by weight, the color may not be displayed smoothly due to insufficient doping, and when it exceeds 15 parts by weight, the efficiency may drop sharply due to concentration extinction.

[0219] When a phosphorescent dopant is used 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) may be added to the upper portion of the light-emitting layer 400 by vacuum deposition or spin coating. The hole blocking material that can be used is not particularly limited, and any known material can be selected and used. For example, Oxadiazole derivatives or benzotriazole derivatives, o-phenanthroline derivatives or hole blocking materials described in Japanese Patent Application Laid-Open No. 11-329734 (A1), among which the most representative ones include bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (Balq) and phenanthroline compounds (for example, BCP (bathocuproine) of UDC), etc. As described above, the light-emitting layer 400 of the present invention may include one or more or two or more blue light-emitting layers.

[0220] In addition, 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 appropriate to select conditions within a range that is almost the same as the conditions for forming the hole injection layer 200. As a generally known substance, a quinoline derivative can be used, and in particular, tris(8-hydroxyquinoline)aluminum (Alq3) or ET4 (6,6'-(3,4-dipodyl-1,1-dimethyl-1H-silanol-2,5-diyl)di-2,2'-bipyridine) can be used.

[0221] Furthermore, 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 methods such as vacuum deposition, spin coating, casting, etc. As the electron injection layer material, known materials such as LiF, NaCl, CsF, Li2O, and BaO can be used.

[0222] At the same time, 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 a vacuum deposition method or a sputtering method. As the material of the second electrode 2000, a variety of metals can be used. As a specific example, materials such as lithium (Li), aluminum (Al), gold (Au), silver (Ag), magnesium (Mg), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) can be used, but are not limited thereto. In addition, in order to obtain a front light-emitting element, a permeable electron injection electrode using ITO or IZO can be used.

[0223] The organic light-emitting element of the present invention can not only use the organic light-emitting element as described above including 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.

[0224] In addition, the thickness of each organic layer formed by the present invention can be adjusted according to the required degree, specifically, it can be 1 to More specifically, it can be 50 to

[0225] The covering layer 3000 is as follows Figure 1As shown, 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 invention is not limited thereto. The cover layer 3000 as described above 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 the transmittance of the cover layer 3000 can be prevented.

[0226] In addition, although Figure 1 Although not shown in the figure, in 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 multiple functions may be additionally formed on the upper part (outer surface) of the cover layer 3000, and more than one single functional layer may be inserted in the middle of the cover layer 3000, but the present invention is not limited thereto.

[0227] Next, the present invention will be described in more detail through a synthesis example of a compound according to an embodiment of the present invention and an example of an organic light-emitting device. The following synthesis example and examples are only used to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

[0228] Synthesis Example 1: Synthesis of Compound 87

[0229]

[0230] In a round-bottom flask, 6.9 g of 1-(4'-bromo-[1,1'-biphenyl]-4-yl)ethanone, 10.0 g of bis(4-(naphthalen-2-yl)phenyl)amine, 3.4 g of sodium tert-butoxide (t-BuONa), 0.2 g of tri(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 0.2 ml of tri-tert-butylphosphine ((t-Bu)3P) were added to 150 ml of toluene and stirred under reflux. The reaction was confirmed by thin layer chromatography (TLC) and terminated by adding water. The organic layer was extracted with dichloromethane (Methylenechloride), filtered under reduced pressure, and then column purified and recrystallized to obtain 9.9 g of compound 87 (yield: 68%).

[0231] m / z:615.26(100.0%), 616.26(50.2%), 617.26(12.5%), 618.27(2.0%)

[0232] Synthesis Example 2: Synthesis of Compound 97

[0233]

[0234] The same method as in Synthesis Example 1 was used, wherein 4',4"'-azanediylbis(([1,1'-biphenyl]-4'-carbonitrile)) was used instead of bis(4-(naphthalen-2-yl)phenyl)amine to synthesize compound 97. (The yield was 61%)

[0235] m / z:565.22(100.0%), 566.22(43.6%), 567.22(9.8%), 568.23(1.3%), 566.21(1.1%)

[0236] Synthesis Example 3: Synthesis of Compound 102

[0237]

[0238] Compound 102 was synthesized by the same method as in Synthesis Example 1, except that bis(4-(quinolin-3-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 65%)

[0239] m / z: 617.25 (100.0%), 618.25 (48.0%), 619.25 (11.8%), 620.26 (1.7%), 618.24 (1.1%)

[0240] Synthesis Example 4: Synthesis of Compound 108

[0241]

[0242] Compound 108 was synthesized by the same method as in Synthesis Example 1 except that bis(4-(benzofuran-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 66%)

[0243] m / z:595.21(100.0%), 596.22(45.9%), 597.22(11.1%), 598.22(1.8%)

[0244] Synthesis Example 5: Synthesis of Compound 109

[0245]

[0246] Compound 109 was synthesized by the same method as in Synthesis Example 1, except that bis(4-(benzo[b]thiophen-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine. (The yield was 70%)

[0247] m / z: 627.17 (100.0%), 628.17 (47.4%), 629.18 (10.2%), 629.16 (9.0%), 630.17 (4.2%), 630.18 (1.7%), 629.17 (1.1%)

[0248] Synthesis Example 6: Synthesis of Compound 112

[0249]

[0250] The same method as in Synthesis Example 1 was used to prepare bis(4-(benzo[d] Compound 112 was synthesized by replacing bis(4-(naphthalen-2-yl)phenyl)amine with bis(4-(benzo[d]oxazol-2-yl)phenyl)amine. (Yield: 67%)

[0251] m / z:597.21(100.0%), 598.21(43.7%), 599.21(10.4%), 600.22(1.3%), 598.20(1.1%)

[0252] Synthesis Example 7: Synthesis of Compound 113

[0253]

[0254] Compound 113 was synthesized by the same method as in Synthesis Example 1 except that bis(4-(benzo[d]thiazol-2-yl)phenyl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 64%)

[0255] m / z: 629.16 (100.0%), 630.16 (46.0%), 631.16 (10.4%), 631.17 (9.3%), 632.16 (4.1%), 632.17 (1.5%)

[0256] Synthesis Example 8: Synthesis of Compound 116

[0257]

[0258] Compound 116 was synthesized by the same method as in Synthesis Example 1 except that bis(4-(2H-benzo[d][1,2,3]triazol-2-yl)phenyl)amine was substituted with bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 59%)

[0259] m / z:597.23(100.0%), 598.23(41.4%), 599.23(9.5%), 598.22(2.6%), 600.24(1.2%)

[0260] Synthesis Example 9: Synthesis of Compound 118

[0261]

[0262] Compound 118 was synthesized by the same method as in Synthesis Example 1, except that bis(4-(imidazo[1,2-a]pyridin-2-yl)phenyl)amine was substituted with bis(4-(naphthalen-2-yl)phenyl)amine. (Yield: 62%)

[0263] m / z:595.24(100.0%), 596.24(43.6%), 597.24(10.2%), 596.23(1.8%), 598.25(1.3%)

[0264] Synthesis Example 10: Synthesis of Compound 131

[0265]

[0266] Compound 131 was synthesized by the same method as in Synthesis Example 1, except that bis(naphtho[2,3-b]benzofuran-3-yl)amine was used instead of bis(4-(naphthalen-2-yl)phenyl)amine. (The yield was 70%)

[0267] m / z:643.21(100.0%), 644.22(50.2%), 645.22(13.1%), 646.22(2.3%)

[0268] Synthesis Example 11 to Synthesis Example 30

[0269] The same method as in Synthesis Example 1 was followed, except that starting material 1 and starting material 2 in Table 1 below were used instead of bis(4-(naphthalen-2-yl)phenyl)amine and 1-(4'-bromo-[1,1'-biphenyl]-4-yl)ethanone to synthesize a compound.

[0270]

Table 1

[0271]

[0272]

[0273]

[0274] Manufacturing of organic light-emitting devices

[0275] Figure 1 Schematic diagram illustrating the structure of a general organic light-emitting element. As an example of the present invention, the present invention has Figure 1The structure of the organic light-emitting element shown in FIG. 1 is shown in FIG. 2 , but an electron injection layer (not shown) is additionally introduced between the electron transport layer (500) and the cathode (2000). Specifically, the organic light-emitting element manufactured is stacked in the order of 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 / covering layer 3000 from bottom to top.

[0276] When manufacturing an organic light emitting element, the substrate 10 may be a transparent glass substrate or a flexible plastic substrate.

[0277] The hole injection electrode 1000 is used as an anode for injecting holes into the organic light emitting element. In order to achieve hole injection, a material with the lowest possible work function is used, and it can be formed using transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO) and graphene.

[0278] The materials shown in Table 2 below were used in the hole injection layer 200 , the hole transport layer 300 , the light emitting layer 400 , the electron transport layer 500 , and the electron injection layer 600 .

[0279] Furthermore, a cathode 2000 for injecting electrons is formed above the electron injection layer 600. As the cathode, various metals can be used, such as aluminum, gold, silver, magnesium, magnesium-silver alloy, and the like.

[0280]

Table 2

[0281]

[0282] Example 1

[0283] The indium tin oxide (ITO) substrate formed with a silver (Ag) reflective layer was washed with distilled water ultrasonic waves. After the distilled water washing was completed, ultrasonic washing was performed using solvents such as isopropyl alcohol, acetone, and methanol, and then dried. Next, NDP9 was doped at 3 wt % in HT01 as a hole injection layer on the top of the indium tin oxide (ITO) substrate and at 4 wt %. The thickness of the deposited layer is 1000 mm, and HT01 is used as a hole transport layer. After being deposited with a thickness of 1000 nm, the dopant BD01 was doped at 3 wt % in the main BH01 as the light-emitting layer. Next, a mixture of ET01 and Liq (1:1, wt. / wt.) was used as an electron transport layer. The thickness is deposited, and then LiF is deposited The electron injection layer was formed by depositing MgAg with a thickness of 15 nm. The compound prepared in Synthesis Example 1 was deposited on The organic light emitting element was manufactured by encapsulating the element in a glove box.

[0284] Example 2 to Example 30

[0285] The same method as in Example 1 was used to produce an organic light-emitting element, wherein a film was formed using the compounds produced in Synthesis Examples 2 to 30 to form a cover layer.

[0286] Comparative Examples 1 to 6

[0287] An organic light emitting element was manufactured in the same manner as in Example 1 except that a film of a cover layer was formed using Comparative Compounds 1 to 6 shown in Table 3 below.

[0288]

Table 3

[0289]

[0290] <Test Example 1> Performance Evaluation of Organic Light Emitting Element

[0291] By applying voltage to a Kiethley 2400 source measurement unit to inject electrons and holes and measuring the brightness of the emitted light using a Konica Minolta spectroradiometer (CS-2000), the performance of the organic light-emitting element was evaluated by measuring the current density and brightness relative to the applied voltage in Example 1, Example 11 to Example 14, Example 20 to Example 27, and Comparative Examples 1 to Comparative Examples 6 under atmospheric pressure conditions. The results are shown in Table 4 below.

[0292]

Table 4

[0293] Classification Op.V mA / cm2 Cd / A QE(%) CIEx CIE LT95 Example 1 3.50 10 7.2 6.0 0.139 0.046 148 Embodiment 11 3.50 10 7.7 6.5 0.140 0.045 152 Example 12 3.51 10 7.8 6.5 0.140 0.045 155 Embodiment 13 3.50 10 8.0 7.0 0.142 0.045 160 Embodiment 14 3.50 10 8.0 7.1 0.140 0.044 161 Embodiment 20 3.50 10 8.6 7.5 0.140 0.045 165 Embodiment 21 3.50 10 8.8 7.7 0.140 0.044 163 Embodiment 22 3.50 10 9.0 8.0 0.140 0.043 167 Embodiment 23 3.50 10 8.5 7.5 0.139 0.045 162 Embodiment 24 3.51 10 8.5 7.6 0.140 0.045 163 Embodiment 25 3.51 10 8.4 7.4 0.140 0.046 163 Embodiment 26 3.51 10 8.7 7.7 0.140 0.046 163 Embodiment 27 3.50 10 9.2 8.1 0.140 0.045 170 Comparative Example 1 3.51 10 6.0 5.1 0.141 0.050 130 Comparative Example 2 3.51 10 6.4 5.2 0.142 0.048 135 Comparative Example 3 3.50 10 6.7 5.6 0.142 0.049 140 Comparative Example 4 3.51 10 6.4 5.5 0.142 0.047 145 Comparative Example 5 3.51 10 5.6 4.7 0.138 0.055 122 Comparative Example 6 3.51 10 5.1 4.3 0.134 0.061 101

[0294] Compared with Comparative Examples 1 to 5, the compound for the cover layer used in the embodiment of the present invention has a high refractive index due to the arylamine structure containing a carbonyl group, and the refractive index can be effectively improved even if the molecular weight is small. In addition, compared with Comparative Example 6, by increasing the π conjugation between the carbonyl group and the amine, by increasing the absorption wavelength in the ultraviolet region and excellent molecular arrangement, a stable thin film can be formed, thereby ensuring thermal stability, and realizing a high-efficiency, long-life organic light-emitting element.

[0295] <Test Example 2> Evaluation of Refractive Index

[0296] Compound 573, Compound 627, Compound 631, and Comparative Compounds 1 to 3 were used to form a 30 nm thick deposited film on a silicon substrate using a vacuum deposition device, and then the refractive index at a wavelength of 450 nm was measured using an ellipsometer (JA Woollam Co. Inc, M-2000X). The results are shown in Table 5 below.

[0297]

Table 5

[0298] @450nm Comparative Compound 1 Comparative Compound 2 Comparative Compound 3 Compound 573 Compound 627 Compound 631 Refractive index, n 2.10 2.17 2.11 2.35 2.48 2.45

[0299] As described in Table 5, it was confirmed that Compound 573, Compound 627, and Compound 631 exhibited high refractive indices of 2.30 or more, more specifically, 2.35 or more. In particular, it was confirmed that Compound 627 and Compound 631 exhibited high refractive indices of 2.40 or more, more specifically, 2.45 or more.

[0300] <Test Example 3> Evaluation of absorption intensity in the ultraviolet region

[0301] In the ultraviolet region, a 30 nm thick deposition film was prepared on a silicon substrate using a vacuum deposition device using compound 573, comparative compound 1, and comparative compound 5, and then the absorption intensity in the range of 360 nm to 500 nm was measured using an ellipsometer device (JA Woollam Co. Inc, M-2000X). The results are shown in Table 2 below.

[0302] The absorption intensity of Compound 573 is 0.7 or more, more specifically 0.8 or more based on a wavelength of 380 nm in the ultraviolet absorption region, and it can be seen that the absorption intensity is increased by more than 30% compared with Comparative Compound 1 and Comparative Compound 5.

Claims

1. A compound for a covering layer represented by the following chemical formula 1, characterized in that: <Chemical Formula 1> In the chemical formula 1, Ar1 and Ar2 are each independently a substituted or unsubstituted C5-C50 aryl group, a substituted or unsubstituted C2-C50 heteroaryl group, or RC(=X)-*, X is each independently O, S, Se, Te or NR, L is a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof, L1 and L2 are each independently a direct bond, a substituted or unsubstituted C5-C50 arylene group, a substituted or unsubstituted C2-C50 heteroarylene group, or a combination thereof, 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 C0-C30 silyl, substituted or unsubstituted C2-C30 dialkylamino, substituted or unsubstituted C3-C50 cycloalkyl, substituted or unsubstituted C1-C50 heterocycloalkyl, substituted or unsubstituted C3-C50 cycloalkenyl, substituted or unsubstituted C2-C50 heterocycloalkenyl, substituted or unsubstituted C5-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, "*" represents the binding position.

2. The compound for covering layer according to claim 1, characterized in that The chemical formula 1 is represented by the following chemical formula 2: <Chemical Formula 2> In the chemical formula 2, The definitions of the same symbols as those in Chemical Formula 1 are the same as those in Chemical Formula 1. R 1 is independently the same as defined above for R, l is an integer from 1 to 4.

3. The compound for covering layer according to claim 1, characterized in that The chemical formula 1 is represented by the following chemical formula 3 or chemical formula 4: <Chemical formula 3> <Chemical Formula 4> In the chemical formula 3 and the chemical formula 4, The same symbols as those in Chemical Formula 1 have the same definitions as in Chemical Formula 1; R1 to R3 are each independently the same as defined above for R; and l, m and n are each independently an integer of 1 to 4.

4. The compound for covering layer according to claim 1, characterized in that The chemical formula 1 is represented by the following chemical formula 5: <Chemical Formula 5> In the chemical formula 5, Definitions of the same symbols as those in Chemical Formula 1 are the same as those in Chemical Formula 1.

5. The compound for covering layer according to claim 1, characterized in that The R is independently selected from the group consisting of a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C5-C18 aryl group, or a combination thereof.

6. The compound for covering layer according to claim 1, characterized in that The R groups are each independently selected from the group consisting of a methyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a combination thereof.

7. The compound for a covering layer according to claim 1, characterized in that One or more of Ar1 and Ar2 are each independently selected from the group consisting of a substituted or unsubstituted fused aryl group having four or less rings and a substituted or unsubstituted fused heteroaryl group having four or less rings.

8. The compound for covering layer according to claim 1, characterized in that One or more of Ar1 and Ar2 are each independently a substituted or unsubstituted C10-C50 aryl group.

9. The compound for covering layer according to claim 1, characterized in that When one or more of Ar1 and Ar2 is a substituted or unsubstituted C2-C50 heteroaryl group, each independently has 1 to 3 of O, S and N as a hetero element.

10. The compound for covering layer according to claim 1, characterized in that The Ar1 to Ar2 are each independently selected from phenyl, naphthyl, quinolyl, isoquinolyl, benzofuranyl, benzothiophenyl, benzo The present invention can be selected from the group consisting of oxazolyl, benzothiazolyl, benzotriazolyl, imidazopyridyl, naphthobenzofuranyl and naphthobenzothiophenyl.

11. The compound for a covering layer according to claim 1, characterized in that: The L is phenylene, biphenylene, pyridylene or a combination thereof, The L1 and L2 are each independently a direct bond, a phenylene group, a biphenylene group, a pyridylene group or a combination thereof.

12. The compound for a covering layer according to claim 1, characterized in that One or more of -L1-Ar1 and -L2-Ar2 are each independently any one of the following chemical structural formulas A-1 to A-37, or include any one of the following chemical structural formulas A-1 to A-37: In the chemical structural formulas A-1 to A-37, q and w are each independently an integer from 0 to 3, R4 is independently deuterium, halogen, nitrile, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, or C1-C3 fluoroalkyl in which hydrogen is replaced by fluorine, and "*" represents a bonding position.

13. The compound for a covering layer according to claim 1, characterized in that: The compound for the covering layer is any one of the following compounds:

14. The compound for a covering layer according to claim 1, characterized in that When a deposited film is produced by deposition to a thickness of 30 nm to 120 nm and then the refractive index at a wavelength of 450 nm is measured, the refractive index of the compound for the capping layer is 2.30 or more.

15. A covering layer for an organic light emitting element, characterized in that: Contains the compound according to any one of claims 1 to 14.

16. An organic light emitting element, characterized in that: A covering layer comprising the compound for a covering layer according to any one of claims 1 to 14.

17. The organic light emitting element according to claim 16, characterized in that: The organic light emitting element comprises: a first electrode; a second electrode; and One or more organic layers are located 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.

18. The organic light emitting element according to claim 16, characterized in that: The thickness of the covering layer is to within the range.

19. The organic light emitting element according to claim 16, characterized in that: exist to At any thickness within the thickness range, the cover layer has a refractive index of 2.30 or more at a wavelength of 450 nm.

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