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

Abstract

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

Description

Technical Field

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

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

[0003] Furthermore, the luminescent materials can be classified according to their luminescence mechanism into fluorescent materials originating from the singlet excited state of electrons, phosphorescent materials originating from the triplet excited state of electrons, and delayed fluorescent materials originating from the electron movement from the triplet excited state to the singlet excited state. They can also be classified according to their luminescence color into blue, green, red, and yellow and vermilion luminescent materials required to achieve a more superior natural color.

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

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

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

[0007] During the transition of the exciton from the excited state to the ground state, light will be generated.

[0008] Furthermore, the efficiency of organic light-emitting elements can generally be divided into internal luminous efficiency and external luminous efficiency. Internal luminous efficiency is related to the efficiency of generating excitons and achieving light conversion in the organic layers between the first and second electrodes, such as hole transport layers, light-emitting layers, and electron transport layers. Theoretically, the internal luminous efficiency of fluorescence is 25%, while that of phosphorescence is 100%.

[0009] Furthermore, external luminous efficiency refers to the efficiency with which light generated in the organic layer is extracted to the outside of the organic light-emitting element. It is known that approximately 20% of the internal luminous efficiency can typically be extracted to the outside. As a method to improve the light extraction efficiency, to prevent the loss of light illuminating the outside due to total internal reflection, various organic compounds with a refractive index of 1.7 or higher are commonly used as a capping layer. Moreover, in order to improve the performance of organic light-emitting elements, efforts have been made to develop organic compounds with high refractive index and thin film stability that can improve external luminous efficiency. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide a compound for a capping layer of an organic light-emitting element that can improve the absorption wavelength in the ultraviolet region while having a wide band gap and high refractive index in the region where visible light is difficult to absorb, thereby achieving high color purity, high efficiency and long service life, and an organic light-emitting element containing the capping layer compound.

[0011] Furthermore, the present invention aims to provide a capping compound and an organic light-emitting element comprising the capping compound, which can improve the thin film arrangement between molecules by increasing the polarizability of the molecules and thereby improve the refractive index, improve the stability to external air and / or moisture, prevent recrystallization between molecules by a higher glass transition temperature (Tg) and decomposition temperature (Td), and maintain the stability of the thin film when heat is generated during the device driving process.

[0012] Next, we will provide a detailed explanation of the topics mentioned above, as well as any additional topics.

[0013] As a means of solving the problems mentioned above,

[0014] As an embodiment of the present invention, a compound for a coating layer represented by the following chemical formula 1 is provided:

[0015] <Chemical Formula 1>

[0016]

[0017] In the chemical formula 1,

[0018] Y is O, S, Se, or Te.

[0019] Ring A and ring B are each independently composed of a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C2-C30 heteroaryl group; one or more of ring A and ring B are substituted or unsubstituted C9 or more fused aryl groups or substituted or unsubstituted C7 or more fused heteroaryl groups.

[0020] X can be CR or N independently.

[0021] R is hydrogen, or a substituted or unsubstituted C1 to C10 alkyl group.

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

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

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

[0026] The coating compound according to the present invention is an aryl or heteroaryl compound containing fused heteroaryl groups with four or more rings as the parent core, which can achieve high color purity by maintaining a wide band gap in the region where visible light is difficult to absorb.

[0027] Furthermore, the coating compound according to the present invention has a structure in which more than four fused heteroaryl groups are incorporated into aryl or heteroaryl groups of C3 to C6, thereby improving the absorption wavelength in the ultraviolet region while maintaining a high refractive index. Therefore, it can improve the external quantum efficiency of organic light-emitting elements and has an excellent effect on improving ultraviolet stability.

[0028] In particular, the coating compound according to the invention ensures excellent intermolecular film alignment by minimizing the volume characteristics of the terminal portion while having an aryl (e.g., phenyl) or heteroaryl (e.g., pyridyl, pyrimidinyl, triazine) core with minimized volume characteristics. Therefore, it can not only achieve refractive index improvement but also significantly improve stability to external air and / or moisture.

[0029] Furthermore, when the capping compound according to the present invention contains fused heteroaryl groups with more than four specific rings, such as benzonaphthiofuran or benzonaphthiophene, it has a higher glass transition temperature (Tg) and decomposition temperature (Td), thus preventing intermolecular recrystallization and maintaining the stability of the film when heat is generated during the device driving process.

[0030] Next, we will explain in detail the effects described above and the additional effects. Attached Figure Description

[0031] Figure 1This is a schematic cross-sectional view illustrating the structure of an organic light-emitting element according to an embodiment of the present invention.

[0032] Figure 2 This is a graph showing the absorption intensity of compounds 45 and 67 used in the capping layer according to an embodiment of the present invention, compared with comparative compound 1 (Ref. 1), in the range of 320 nm to 460 nm.

[0033] [Symbol Explanation]

[0034] 100: Substrate

[0035] 200: Hole injection layer

[0036] 300: Hole Transport Layer

[0037] 400: Emissive layer

[0038] 500: Electron transport layer

[0039] 600: Electron Injection Layer

[0040] 1000: Electrode 1 (Anode)

[0041] 2000: Second electrode (cathode)

[0042] 3000: Overlay Detailed Implementation

[0043] Before providing a detailed description of the invention, it should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the scope of the invention, which should be defined only by the scope of the appended claims. Unless otherwise expressly stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0044] Throughout this specification and the claims, unless otherwise expressly stated, the terms "comprise," "comprises," or "comprising" are used only to indicate that the mentioned object, step, or series of objects and steps are included, and do not preclude any other object, step, or series of objects or steps.

[0045] Throughout this specification and the claims, the term "aryl" may refer to substances including phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrene, triphenylene, phenylene, etc. Benzyl, fluoranyl, benzo[a]fluorene, benzo[a]triphenylene, benzo[a] "Hyperaryl" refers to aromatic rings with C5-50 groups, including pyrrole, anthracene, piracene, and pyrene rings. "Heteroaryl" refers to groups containing pyrrole, pyrazinyl, pyridinyl, indole, isoindole, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, quinolinyl, isoquinolinyl, quinoxalinyl, carbazolyl, phenanthridine, acridine, phenanthridine, thiophene, and those composed of pyridine, pyrazine, pyrimidine, pyridazine, triazine, indole, quinoline, acridine, pyrrolidine, and diphenyl rings. Alkyl ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, azole ring, A C2-50 aromatic ring containing one or more heterocyclic elements, formed by heterocyclic groups such as diazole ring, benzofuran ring, thiazole ring, thiadiazole ring, benzothiophene ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, and dibenzofuran ring.

[0046] In addition, Ar in the chemical formula x (where x is an integer) unless otherwise explicitly defined, L represents a substituted or substituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, L x (where x is an integer) unless otherwise explicitly defined, R represents a directly bonded, substituted or unsubstituted C6–C50 arylene, or a substituted or unsubstituted C2–C50 heteroarylene, R x (where x is an integer) Unless otherwise explicitly defined, it means hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 thioether, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0047] Throughout this specification and the claims, the term "substituted or unsubstituted" means derived from deuterium, halogen, amino, cyano, nitrile, nitro, nitrosyl, aminosulfonyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylthioalkyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1-C12 N The device may have one or more groups selected from the group consisting of alkylamino, C2-C20 N,N-dialkylamino, substituted or unsubstituted C1-C30 thioether, C1-C6 N-alkylaminosulfonyl, C2-C12 N,N-dialkylaminosulfonyl, C3-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C2-C50 heteroaryl, but is not particularly limited thereto. Furthermore, throughout this specification, unless otherwise expressly stated, the same symbols have the same meaning. Additionally, * represents a bonding position.

[0048] Furthermore, unless otherwise expressly stated to the contrary, various embodiments of the present invention may be combined with certain other embodiments. The embodiments of the present invention and their effects will now be described.

[0049] The present invention will now be described in detail.

[0050] The compounds according to the present invention can be represented by the following chemical formula 1:

[0051] <Chemical Formula 1>

[0052]

[0053] In the chemical formula 1,

[0054] Y is O, S, Se, or Te.

[0055] Ring A and ring B are each independently composed of a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C2-C30 heteroaryl group; one or more of ring A and ring B are substituted or unsubstituted C9 or more fused aryl groups or substituted or unsubstituted C7 or more fused heteroaryl groups.

[0056] X can be CR or N independently.

[0057] R is hydrogen, or a substituted or unsubstituted C1 to C10 alkyl group.

[0058] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0059] L, L1, and L2 are each independently a directly bonded, substituted, or unsubstituted C6-C50 arylene, or a substituted or unsubstituted C2-C50 heteroarylene.

[0060] In the aforementioned content, the substituents used during substitution may include deuterium, halogen, cyano, 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 thioether, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0061] The capping layer compound represented by Chemical Formula 1 is an aryl (e.g., phenyl) or heteroaryl (e.g., pyridyl, pyrimidinyl, triazineyl) compound whose core contains fused heteroaryl groups of four or more specific rings, such as benzo[a]naphthofuranyl or benzo[a]naphthothiopheneyl. It can achieve high color purity by maintaining a wide band gap in the region where visible light is difficult to absorb, and can also increase the absorption wavelength in the ultraviolet region while maintaining a high refractive index. Therefore, using the compound represented by Chemical Formula 1 as a capping layer in an organic light-emitting element can improve external quantum efficiency and achieve excellent stability against ultraviolet light. Furthermore, because the capping layer compound according to the present invention has a high glass transition temperature (Tg) and decomposition temperature (Td), it can prevent intermolecular recrystallization during lamination as a capping layer and maintain the stability of the film when heat is generated during the driving process of the organic light-emitting element.

[0062] Specifically, chemical formula 1 can be represented by the following chemical formula 2:

[0063] <Chemical Formula 2>

[0064]

[0065] In the chemical formula 2,

[0066] The definitions of X, Y, ring A, ring B, Ar1, and Ar2 are the same as those in chemical formula 1.

[0067] l, m, and n can each be an integer from 0 to 5, specifically, an integer from 0 to 2.

[0068] R1 to R3 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 thioether, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0069] p can be an integer from 0 to 4, each independently.

[0070] When the coating compound represented by the aforementioned chemical formula 2 is L, L1, and L2, each of which is directly bonded or consists of one or more phenylene groups, the refractive index can be effectively improved while minimizing the absorption wavelength in the blue region, as described above.

[0071] Specifically, chemical formula 2 can be represented by the following chemical formula 2-1:

[0072] <Chemical Formula 2-1>

[0073]

[0074] In the chemical formula 2-1,

[0075] The definitions of X, Y, ring A, ring B, Ar1, Ar2, R1 to R3, l, m, n, and p are the same as those in chemical formula 2.

[0076] When the coating compound represented by the chemical formula 2-1 is L, L1, and L2, each of which is directly bonded or has one or more para-bonded 1,4-phenylene compounds, the refractive index can be improved more effectively as described above.

[0077] Furthermore, the chemical formula 1 can be represented by the following chemical formula 3 or chemical formula 4:

[0078] <Chemical Formula 3>

[0079]

[0080] <Chemical Formula 4>

[0081]

[0082] In chemical formulas 3 and 4,

[0083] The definitions of X, Y, ring A, ring B, L, L1, L2, and Ar2 are the same as those in the chemical formula 1. Multiple rings of Y, A, and B may be the same or different from each other.

[0084] The capping compound represented by the chemical formula 3 or chemical formula 4 has a structure in which one or more fused heteroaryl groups with four or more rings are contained in an aryl or heteroaryl core of C3 to C6.

[0085] The capping compound represented by the chemical formula 3 has a structure in which two or more fused heteroaryl groups of four rings are directly or through a linker bonded to a C3 to C6 aryl or C3 to C6 heteroaryl core, thereby achieving a high refractive index even with a low molecular weight.

[0086] Furthermore, the coating compound represented by the aforementioned chemical formula 4 is a compound having a structure in which three or more fused heteroaryl groups are directly or through a linker bonded to a C3 to C6 aryl or C3 to C6 heteroaryl core, thereby more effectively improving the refractive index.

[0087] Specifically, the compound of chemical formula 1 can be represented by chemical formula 5 or chemical formula 6 as follows:

[0088] <Chemical Formula 5>

[0089]

[0090] <Chemical Formula 6>

[0091]

[0092] In chemical formulas 5 and 6,

[0093] The definitions of X, Y, Ar1, and Ar2 are the same as those in Chemical Formula 1.

[0094] Ring A and ring B are either fused aryl groups with substituted or unsubstituted C9 or more substituted groups, or fused heteroaryl groups with substituted or unsubstituted C7 or more substituted groups.

[0095] l, m, and n can each be an integer from 0 to 5, specifically, an integer from 0 to 2.

[0096] R1 to R3 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 thioether, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0097] p can be an integer from 0 to 4, each independently.

[0098] When the coating compound represented by the aforementioned chemical formula 5 or chemical formula 6 is a phenyl ring with ring A or ring B being a phenyl group and L, L1, and L2 are each directly bonded or one or more phenylene groups, the refractive index can be effectively improved while minimizing the absorption wavelength in the blue region, as described above.

[0099] Specifically, chemical formula 5 and chemical formula 6 can be represented by the following chemical formulas 5-1 and 6-1, respectively:

[0100] <Chemical Formula 5-1>

[0101]

[0102] <Chemical Formula 6-1>

[0103]

[0104] In the aforementioned chemical formulas 5-1 and 6-1,

[0105] The definitions of X, Y, Ar1 and Ar2, ring A, ring B, l, m, n, R1 to R3 and p are the same as those in chemical formulas 5 and 6.

[0106] When the capping compound represented by the aforementioned chemical formula 5-1 or chemical formula 6-1 is L, L1, and L2, each of which is directly bonded or has one or more para-bonded 1,4-phenylene compounds, the refractive index can be improved more effectively in the case described above.

[0107] Specifically, chemical formula 5 and chemical formula 6 can be represented by the following chemical formulas 5-2 and 6-2, respectively:

[0108] <Chemical Formula 5-2>

[0109]

[0110] <Chemical Formula 6-2>

[0111]

[0112] In chemical formulas 5-2 and 6-2,

[0113] The definitions of X, Y, Ar1, Ar2, l, m, n, R1 to R3, and p are the same as those in chemical formulas 5 and 6.

[0114] The capping layer compound represented by chemical formula 5-2 or chemical formula 6-2 has an A ring or B ring that is phenyl or naphthyl. The structure is formed by direct or linear binding of 1,4-phenylene groups with one or more para-links to C3- to C6 aryl or C3- to C6 heteroaryl groups.

[0115] At this point, the capping compound represented by the chemical formula 5-2 has a naphthyl ring A and a phenyl ring B. The structure linearly bonded to C3 to C6 aryl or C3 to C6 heteroaryl groups can achieve a high refractive index due to the excellent thin film arrangement, and can also significantly improve the absorption wavelength intensity in the ultraviolet region.

[0116] Furthermore, the capping compound represented by the aforementioned chemical formula 6-2 has a phenyl A ring and a naphthyl B ring. The structure of linearly binding to aryl or heteroaryl groups of C3 to C6 can significantly increase the refractive index and improve stability when exposed to external ultraviolet light.

[0117] Furthermore, in any one of chemical formulas 1 to 6 according to the present invention, the Y may be O or S.

[0118] As an example, Y can be O, which, as described above, allows for a high refractive index and also effectively reduces the deposition temperature during deposition by decreasing the molecular weight of the compound.

[0119] As another example, Y can be S, which, as described above, not only increases the refractive index but also achieves a higher glass transition temperature (Tg), thus facilitating the formation of stable thin films.

[0120] Furthermore, in any one of chemical formulas 1 to 6 according to the present invention, one or more of rings A and B may contain fused aryl groups of C10 to C20, specifically, naphthyl groups. In the case described above, not only can the refractive index of the compound be effectively increased, but the deposition temperature can also be significantly reduced, thereby forming a stable thin film by improving the thermal stability of the compound.

[0121] More specifically, in any one of chemical formulas 1 to 4 according to the present invention,

[0122] The It can be any one of the structures represented by structures A-1 to A-21 below, or include any one of the structures represented by structures A-1 to A-21 below:

[0123]

[0124]

[0125] In structures A-1 to A-21, W is O or S.

[0126] In the With the structure described above, the refractive index of the compound can be increased and the absorption wavelength in the blue region can be minimized, and a stable thin film can be effectively formed by improving thermal stability.

[0127] Furthermore, in any one of the chemical formulas 1 to 3, 5, and 6,

[0128] Ar1 and Ar2 can each independently be any one of the structures represented by structures B-1 to B-26 below, or include any one of the structures represented by structures B-1 to B-26 below:

[0129]

[0130]

[0131] In structures B-1 to B-26,

[0132] Z can be CR'R", NR', O, or S.

[0133] Z1 is either CR' or N.

[0134] R' and R" can each independently be hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C10 alkyl, or substituted or unsubstituted C6-C20 aryl. Specifically, they can be hydrogen, methyl, ethyl, or phenyl. Although not specifically limited, R' and R" can also independently be at the *- binding position.

[0135] When Ar1 and Ar2 have the structures described above, the substituent volume characteristics of chemical formulas 1 to 3, 5 and 6 can be minimized, thus ensuring excellent intermolecular film arrangement, achieving high refractive index and enhancing absorption in the ultraviolet region.

[0136] In particular, Ar1 and Ar2 each independently comprise any one of the structures represented by structure B-1, structure B-3, structure B-5, and structures B-6 to B-12, specifically, they can be phenyl, pyridinyl, pyrimidinyl, benzonitrile, bipyridinyl, quinolinyl, quinazolinyl, phenylquinazolinyl, naphthyl, phenanthrene, triphenylene, benzofuranyl, benzothiophene, dibenzofuranyl, dibenzothiophene, benzo[] The azolium or benzothiazolium group, more specifically, can be naphthyl, benzofuran, and / or benzo[a] group. Azolium group. In the case described above, not only can the refractive index be increased, but light absorption in the blue region can also be minimized, and the deposition temperature can be lowered. Therefore, it is beneficial to form a stable film by improving thermal stability.

[0137] Furthermore, in any one of Chemical Formulas 1 to 6, L, L1, and L2 can each be independently a directly bonded, phenylene, biphenylene, or pyridyl group. When L, L1, and L2 have the structures described above, the π-conjugation of the compound can be minimized, thus improving the refractive index while minimizing the absorption wavelength in the visible light region. Moreover, because the substituents are linearly connected via the connecting lines, the ultraviolet absorption intensity can be improved, resulting in a higher refractive index, thereby effectively improving the efficiency and lifespan of the organic light-emitting element.

[0138] The following compounds are specific examples of compounds for use in coatings according to the present invention. These examples are merely illustrative and are not intended to limit the scope of the invention.

[0139]

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[0236] One embodiment of the compound for the capping layer according to the present invention can be synthesized by the Suzuki reaction as shown in the following reaction formula:

[0237]

[0238] In another embodiment of the invention, an organic light-emitting element is provided in which the cover layer contains the cover layer compound according to the invention as described above.

[0239] The organic light-emitting element includes: a first electrode; a second electrode facing the first electrode; and one or more organic layers between the first electrode and the second electrode; the capping layer may be disposed outside any one or more of the first electrode and the second electrode.

[0240] The organic light-emitting element according to the present invention will now be described in more detail.

[0241] In one embodiment of the present invention, the organic light-emitting element may include a first electrode, a second electrode, and one or more organic layers between the first electrode and the second electrode, wherein the covering layer may be disposed outside any one or more of the first electrode and the second electrode.

[0242] Specifically, the side of the first or second electrode adjacent to the organic layer between the first and second electrodes is called the inner side, and the side not adjacent to the organic layer is called the outer side. That is, when the capping layer is disposed on the outer side of the first electrode, the first electrode will be located between the capping layer and the organic layer, and when the capping layer is disposed on the outer side of the second electrode, the second electrode will be located between the capping layer and the organic layer.

[0243] Furthermore, in one embodiment of the present invention, the inner sides of the first electrode and the second electrode of the organic light-emitting element may be interposed with one or more layers of various organic materials, while a capping layer may be formed on the outer side of either the first electrode or the second electrode. That is, the capping layer may be formed simultaneously on the outer side of the first electrode and the outer side of the second electrode, or it may be formed only on the outer side of the first electrode or the outer side of the second electrode.

[0244] At this time, the capping layer may contain a capping compound according to the present invention, may contain only a capping compound according to the present invention, or may contain two or more known compounds simultaneously.

[0245] Furthermore, the refractive index of the coating layer at a wavelength of 450nm can be 2.20 or higher, specifically 2.25 or higher, more specifically 2.30 or higher, and most specifically 2.35 or higher, while the ultraviolet absorption intensity at a wavelength of 350nm can be 0.8 or higher, specifically 1.0 or higher.

[0246] Furthermore, the organic layer may include a hole transport layer, a light-emitting layer, and an electron transport layer that typically constitute the light-emitting part, but is not limited to these.

[0247] Specifically, according to one embodiment of the present invention, the organic light-emitting element may include one or more organic layers constituting light-emitting portions such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) between the first electrode (anode) and the second electrode (cathode).

[0248] Figure 1 This is a cross-sectional view illustrating the structure of an organic light-emitting element according to an embodiment of the present invention. An organic light-emitting element according to one embodiment of the present invention can be configured as follows... Figure 1 The structure shown is manufactured.

[0249] 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 capping layer 3000 are stacked sequentially from bottom to top.

[0250] The substrate 100 can be a substrate commonly used in organic light-emitting elements, especially a transparent glass substrate or a flexible plastic substrate with excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of processing and water resistance.

[0251] Furthermore, the first electrode 1000 is used as a hole injection electrode for injecting holes into an organic light-emitting element. To achieve hole injection, the first electrode 1000 is manufactured using a material with the lowest possible work function, and can be formed using transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene.

[0252] Meanwhile, the hole injection layer 200 can be formed by depositing the hole injection layer material on the upper part of the first electrode 1000 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Blodgett method. When forming the hole injection layer 200 by vacuum deposition, the deposition conditions will vary depending on the compound used as the material of the hole injection layer 200, the desired structure of the hole injection layer 200, and its thermal properties. Typically, deposition temperatures of 50–500°C and 10… -8 Up to 10 -3 The vacuum level of the Torr is 0.01 to... The deposition rate and The layer thickness should be appropriately selected within the range of up to 5 μm. Furthermore, a charge generation layer can be deposited on the surface of the hole injection layer 200 as needed. Common materials can be used as the charge generation layer material, such as hexacyano-hexaazabenzophenanthrene (HATCN).

[0253] Furthermore, the hole transport layer 300 can be formed by depositing hole transport layer material on top of the hole injection layer 200 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the hole transport layer 300 by the vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferable to select conditions within a range almost identical to those for forming the hole injection layer 200. The hole transport layer 300 can be formed using known compounds. The hole transport layer 300 described above can be one or more layers, and although... Figure 1 Although not illustrated, a light-emitting auxiliary layer can be added above the hole transport layer 300.

[0254] Simultaneously, the light-emitting layer 400 can be formed by depositing a light-emitting layer material on top of the hole transport layer 300 or the light-emitting auxiliary layer using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the light-emitting layer 400 by vacuum deposition, the deposition conditions will vary depending on the compound used, but are generally preferably selected within a range of conditions almost identical to those for forming the hole injection layer 200. Known compounds can be used as the light-emitting layer material, either as the main agent or dopant.

[0255] When phosphorescent dopants are used simultaneously in the light-emitting layer material, to prevent triplet excitons or holes from diffusing into the electron transport layer 500, a stacked hole-blocking material (HBL) can be added to the upper part of the light-emitting layer 400 using vacuum deposition or spin coating. The hole-blocking material used is not particularly limited; any known material can be used. For example, it can be... Diazole derivatives or benzotriazole derivatives, o-diazaphenanthroline derivatives, or hole-blocking materials described in Japanese Patent Application Publication No. 11-329734 (A1), among which the most representative include Balq (bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum), phenanthroline compounds (e.g., UDC's BCP), etc. The light-emitting layer 400 of the present invention, as described above, may comprise one or more blue light-emitting layers.

[0256] Furthermore, the electron transport layer 500 is formed on top of the light-emitting layer 400 and can be formed by methods such as vacuum deposition, spin coating, or casting. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally preferably selected within the same range as those for the formation of the hole injection layer 200.

[0257] Furthermore, the electron injection layer 600 can be formed by depositing electron injection layer material on the upper part of the electron transport layer 500, and can be formed by methods such as vacuum deposition, spin coating, casting, etc.

[0258] Meanwhile, the second electrode 2000 serves as an electron injection electrode and can be formed on the upper part of the electron injection layer 600 by methods such as vacuum deposition or spin coating. Various metals can be used as the material for the second electrode 2000. Specific examples include substances such as aluminum, gold, silver, and magnesium, but it is not limited to these.

[0259] The organic light-emitting element of the present invention can not only use the organic light-emitting element containing the capping layer 3000, the first electrode 1000, the hole injection layer 200, the hole transport layer 300, the light-emitting layer 400, the electron transport layer 500, the electron injection layer 600, the second electrode 2000 and the capping layer 3000 as described above, but can also use organic light-emitting elements with various structures, and can also add an intermediate layer containing one or two layers as needed.

[0260] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted according to the desired degree, specifically from 10 to 1000 nm, and more specifically from 20 to 150 nm.

[0261] The covering layer 3000, as Figure 1 As shown, the hole injection layer 200 may be formed on the outer side of the first electrode 1000 where no hole injection layer 200 is formed. Similarly, the electron injection layer 600 may be formed on the outer side of the second electrode 2000 where no electron injection layer 600 is formed, but this is not a limitation. The capping layer 3000 described above can be formed by a deposition process, and the thickness of the capping layer 3000 can be 100 mm to... More specifically, it could be 300 to By adjusting the thickness as described above, the problem of reduced transmittance of the cover layer 3000 can be prevented.

[0262] In addition, although Figure 1 Although not illustrated, according to one embodiment of the present invention, an organic layer for performing various functions may be additionally formed between the cover layer 3000 and the first electrode 1000 or between the cover layer 3000 and the second electrode 2000. Alternatively, an organic layer for performing various functions may also be additionally formed on the upper part (outer surface) of the cover layer 3000, but this is not a limitation.

[0263] Next, the present invention will be described in more detail through examples of the synthesis of compounds according to an embodiment of the present invention and examples of the manufacture of organic light-emitting elements. The following synthesis examples and embodiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following embodiments.

[0264] <Synthetic Example 1> Synthesis of Compound 9

[0265]

[0266] After adding 400 mL of 1,4-dioxane to a round-bottom flask and dissolving 20.0 g of 2,2'-(5'-bromo-[1,1':3',1”-terphenyl]-4,4”-diyl)dinaphthalene and 11.20 g of naphtho[2,3-b]benzofuran-3-ylboronic acid, 54 mL of 2 M K₂CO₃ and 1.23 g of Pd(PPh₃)₄ were added, and the mixture was refluxed with stirring. The extent of the reaction was confirmed by thin-layer chromatography (TLC), and the reaction was terminated after the addition of water. The organic layer was extracted with dichloromethane (MC) and recrystallized after vacuum filtration to obtain 17.67 g of compound 9 (yield 71%).

[0267] m / z: 698.26 (100.0%), 699.26 (58.4%), 700.27 (17.2%), 701.27 (3.3%)

[0268] <Synthetic Example 2> Synthesis of Compound 11

[0269]

[0270] The same procedure as in Synthesis Example 1 was followed, in which 16.53 g of compound 11 (68% yield) was synthesized by substituting 20 g of 2,2'-(5'-bromo-[1,1':3',1”:4”,1”'-quaterphenyl]-4,4”'-diyl)dinaphthalene.

[0271] m / z: 774.29 (100.0%), 775.30 (65.4%), 776.30 (21.2%), 777.30 (4.5%)

[0272] <Synthetic Example 3> Synthesis of Compound 45

[0273]

[0274] After adding 200 mL of 1,4-dioxane to a round-bottom flask and dissolving 10.0 g of 3,5-dibromo-1,1':4',1”:4”,1”'-quaterphenyl and 12.42 g of naphtho[2,3-b]benzofuran-3-ylboronicacid, 54 mL of K₂CO₃ (2 M) and 1.0 g of Pd(PPh₃)₄ were added, and the mixture was refluxed with stirring. The extent of the reaction was confirmed by thin-layer chromatography (TLC), and the reaction was terminated after the addition of water. The organic layer was extracted with dichloromethane (MC) and recrystallized after vacuum filtration to obtain 10.66 g of compound 45 (yield 67%).

[0275] m / z: 738.26 (100.0%), 739.26 (61.0%), 740.26 (18.5%), 741.27 (3.6%)

[0276] <Synthetic Example 4> Synthesis of Compound 47

[0277]

[0278] The same procedure as in Synthesis Example 3 was followed, in which 10.74 g of compound 47 (66% yield) was synthesized by replacing 3,5-dibromo-1,1':4',1”:4”,1”'-quaterphenyl with 10 g of 2-(3',5'-dibromo-[1,1'-biphenyl]-4-yl)naphthalene.

[0279] m / z: 712.24(100.0%), 713.24(58.5%), 714.25(17.0%), 715.25(3.5%)

[0280] <Synthetic Example 5> Synthesis of Compound 67

[0281]

[0282] After adding 200 mL of 1,4-dioxane to a round-bottom flask and dissolving 10.0 g of 1,3,5-tribromobenzene and 27.47 g of naphtho[2,3-b]benzofuran-3-ylboronic acid, 80 mL of K₂CO₃ (2 M) and 1.84 g of Pd(PPh₃)₄ were added and the mixture was refluxed with stirring. The extent of the reaction was confirmed by thin-layer chromatography (TLC), and the reaction was terminated after the addition of water. The organic layer was extracted with dichloromethane (MC), filtered under reduced pressure, and recrystallized to obtain 15.93 g of compound 67 (69% yield).

[0283] m / z: 726.22 (100.0%), 727.22 (58.5%), 728.23 (17.0%), 729.23 (3.6%)

[0284] <Synthetic Example 6> Synthesis of Compound 153

[0285]

[0286] The same procedure as in Synthesis Example 1 was followed, except that 20 g of naphtho[2,1-b]benzofuran-9-ylboronic acid was used instead of naphtho[2,3-b]benzofuran-3-ylboronic acid, thus yielding 16.68 g of compound 153 (yield 67%).

[0287] m / z: 698.26 (100.0%), 699.26 (58.4%), 700.27 (17.2%), 701.27 (3.3%)

[0288] <Synthetic Example 7> Synthesis of Compound 393

[0289]

[0290] The same procedure as in Synthesis Example 1 was followed, except that 11.89 g of benzo[b]naphtho[2,3-d]thiophen-3-yl boronic acid was used instead of naphtho[2,3-b]benzofuran-3-ylboronic acid, to obtain 16.55 g of compound 393 (yield 65%).

[0291] m / z: 714.24 (100.0%), 715.24 (59.6%), 716.24 (17.2%), 716.23 (4.5%), 717.25 (3.2%), 717.24 (2.8%)

[0292] Manufacturing of organic light-emitting elements

[0293] Figure 1 This is a schematic diagram illustrating the structure of a typical organic light-emitting element, used as an example of the present invention. Figure 1 Based on the illustrated organic light-emitting element structure, a charge generation layer (not shown) is added between the hole injection layer 200 and the hole transport layer 300, and an electron injection layer 600 is added between the electron transport layer 500 and the cathode 2000. Specifically, the manufactured organic light-emitting element is formed by stacking the following layers from bottom to top in the following order: substrate 100 / anode (hole injection electrode 1000) / hole injection layer 200 / charge generation layer (not shown) / hole transport layer 300 / light-emitting layer 400 / electron transport layer 500 / electron injection layer 600 / cathode (electron injection electrode 2000) / capping layer 3000.

[0294] 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.

[0295] Table 1

[0296]

[0297] <Example 1>

[0298] An indium tin oxide (ITO) substrate with a silver (Ag) reflective layer was cleaned using ultrasonic waves with distilled water. After washing with distilled water, ultrasonic cleaning was performed using solvents such as isopropanol, acetone, and methanol, followed by drying. Next, a hole injection layer was formed on the ITO substrate using a thermal evaporator. HI, HATCN and its role as a hole transport layer The NPB was then used to form a film by doping the BH substrate with dopant BD at 3% by weight. The light-emitting layer is then formed. Next, a film is deposited to form the electron transport layer. The ET:Liq (1:1) was then deposited using LiF to form... After the electron injection layer, a 15 nm cathode was formed using MgAg deposition, which was then deposited as a capping layer to form... The thickness of the compound was obtained by synthesis example 1. An organic light-emitting element was fabricated by encapsulating the element in a glove box.

[0299] Example 2 to Example 7

[0300] The organic light-emitting element was manufactured using the same method as in Example 1, wherein a capping layer was formed by forming a film of the compound manufactured in Synthesis Examples 2 to 7.

[0301] Comparative Examples 1 to 5

[0302] Organic light-emitting elements were manufactured by forming a capping layer using comparative compounds 1 (Ref. 1) to 5 (Ref. 5) as shown in Table 2 below, respectively, in accordance with the same method as in Example 1.

[0303] Table 2

[0304]

[0305] <Experimental Example 1> Performance Evaluation of Organic Light-Emitting Components

[0306] By injecting electrons and holes by applying a voltage to a Kiethley 2400 source measurement unit and measuring the brightness of the emitted light using a Konica Minolta spectroradiometer (CS-2000), the performance of the organic light-emitting elements of Examples 1 to 7 and Comparative Examples 1 to 5 was evaluated under atmospheric pressure conditions, namely, the current density and brightness relative to the applied voltage. The results are shown in Table 3.

[0307] Table 3

[0308] Classification Op.V <![CDATA[mA / cm 2 ]]> Cd / A CIEx CIEy LT97 Example 1 3.49 10 7.75 0.143 0.044 168 Example 2 3.50 10 7.65 0.142 0.045 158 Example 3 3.50 10 7.84 0.144 0.043 174 Example 4 3.50 10 7.82 0.144 0.043 172 Example 5 3.49 10 7.87 0.142 0.043 178 Example 6 3.50 10 7.60 0.142 0.045 153 Example 7 3.49 10 7.80 0.144 0.043 170 Comparative Example 1 3.51 10 6.02 0.136 0.055 72 Comparative Example 2 3.52 10 6.70 0.138 0.052 86 Comparative Example 3 3.51 10 6.84 0.139 0.050 98 Comparative Example 4 3.51 10 7.03 0.139 0.050 109 Comparative Example 5 3.52 10 6.95 0.138 0.050 116

[0309] By comparing the embodiments of the present invention, it can be found that the organic light-emitting elements of the embodiments can not only achieve a lower driving voltage, but also have a very good effect on improving luminous efficiency.

[0310] Specifically, referring to Table 3, the organic light-emitting element according to the embodiments of the present invention utilizes a compound containing a specific four-ring structure such as benzofuran or benzonaphthiophene group to form a capping layer. Compared with the organic light-emitting elements of Comparative Examples 1 to 5, it can achieve a higher refractive index and significantly increase the absorption wavelength in the ultraviolet region, thereby achieving excellent efficiency and improved lifespan of the organic light-emitting element.

[0311] Furthermore, compared with the organic light-emitting element of the comparative example, the organic light-emitting element of the embodiment can prevent the decrease of refractive index by forming a capping layer using a compound with a benzene ring having minimized volume characteristics and an extended group at the end, and form a stable film through excellent film arrangement. Moreover, even with a smaller molecular weight, excellent refractive index improvement can be achieved, thereby exhibiting high color purity, high efficiency and long service life.

[0312] <Experimental Example 2> Evaluation of the refractive index of the coating compound

[0313] Using the compounds from Synthesis Example 2 (Compound 11), Synthesis Example 3 (Compound 45), Synthesis Example 4 (Compound 47), Synthesis Example 5 (Compound 67), Comparative Example 1 (Comparative Compound 1), and Comparative Example 2 (Comparative Compound 2), 30 nm thick films were deposited on silicon substrates using a vacuum deposition apparatus. The refractive index at 450 nm was then measured using an ellipsometry (JAWoollam Co. Inc., M-2000X). The results are shown in Table 4 below.

[0314] Table 4

[0315]

[0316] As shown in Table 4 above, it can be confirmed that compounds 11, 45, 47, and 67 exhibit high refractive indices of 2.2 or higher, specifically 2.25 or higher, with a maximum of 2.35 or higher. Because the compounds according to the present invention exhibit the high refractive indices described above, organic light-emitting elements with significantly improved external quantum efficiency and lifespan can be achieved when applied to a capping layer.

[0317] <Experimental Example 3> Evaluation of the UV absorption intensity of the compound used in the coating layer

[0318] Using the capping layer compounds from Synthesis Example 3 (Compound 45), Synthesis Example 5 (Compound 67), and Comparative Example 1 (Comparative Compound 1), respectively, 30 nm thick deposition films were fabricated on silicon substrates using a vacuum deposition apparatus. The absorption wavelengths in the range of 320 nm to 460 nm were then measured using an ellipsometer (JAWoollam Co. Inc., M-2000X). The results are as follows: Figure 2 As shown.

[0319] The result is as follows Figure 2 As shown, regarding the absorption intensity in the ultraviolet region of 350 nm, the compound of Synthetic Example 3 has an intensity of 0.8 or higher, and the compound of Synthetic Example 5 has an intensity of 1.0 or higher. It can be confirmed that compared to Comparative Compound 1 used in Comparative Example 1, the absorption intensity is increased by more than 30%, specifically by more than 60%. Furthermore, the absorption intensity in the ultraviolet region, i.e., below 380 nm, is generally improved compared to Comparative Compound 1. The capping layer compound according to the present invention has a high refractive index and high absorption intensity in the ultraviolet region as described above, thus significantly improving the efficiency and lifespan of organic light-emitting elements.

Claims

1. A compound for use as a coating, represented by the following chemical formula 1: Chemical Formula 1 In the chemical formula 1, Y is either O or S. Each of rings, A and B, can be either phenyl or naphthyl. X can be CR or N independently. R is hydrogen, or a substituted or unsubstituted C1 to C10 alkyl group. Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group. L, L1, and L2 are each independently a directly bonded, phenylene, biphenylene, or pyridyl group, and may or may not be deuterated. When the above is substituted, the substituent is deuterium, halogen, cyano, nitro, nitrile, C1~C30 alkyl, C1~C30 alkoxy, C1~C30 thioether, C6~C50 aryl, or C2~C50 heteroaryl.

2. The compound for the coating layer according to claim 1, The chemical formula 1 is represented by the following chemical formula 2: Chemical formula 2 In the chemical formula 2, The definitions of X, Y, ring A, ring B, Ar1, and Ar2 are the same as those in chemical formula 1. l, m, and n are each an independent integer from 0 to 2. R1 to R3 are each independently either hydrogen or deuterium. p can be an integer from 0 to 4, each independently.

3. The compound for the coating layer according to claim 1, The chemical formula 1 is represented by the following chemical formula 3 or chemical formula 4: Chemical formula 3 Chemical Formula 4 In chemical formulas 3 and 4, The definitions of X, Y, ring A, ring B, L, L1, L2, and Ar2 are the same as those in the chemical formula 1. Multiple rings of Y, A, and B may be the same or different from each other.

4. The compound for the coating layer according to claim 1, The chemical formula 1 is represented by the following chemical formula 5 or chemical formula 6: Chemical formula 5 Chemical Formula 6 In chemical formulas 5 and 6, The definitions of X, Y, Ar1, and Ar2 are the same as those in Chemical Formula 1. Rings A and B are naphthyl groups. l, m, and n are each an independent integer from 0 to 2. R1 to R3 are each independently either hydrogen or deuterium. p can be an integer from 0 to 4, each independently.

5. The compound for the coating layer according to claim 1, The It is any one of the structures represented by the following structures A-1 to A-13: In structures A-1 to A-13, W is O or S.

6. The compound for the coating layer according to claim 1, Ar1 and Ar2 are each independently any one of the structures represented by structures B-1 to B-26 below: In structures B-1 to B-26, Z can be CR'R", NR', O, or S. Z1 is either CR' or N. R' and R" are each independently hydrogen, deuterium, halogen group, cyano group, C1-C10 alkyl group, or C6-C20 aryl group.

7. The compound for the coating layer according to claim 6, Ar1 and Ar2 each independently include any one of the structures represented by structure B-1, structure B-3, structure B-5, and structures B-6 to B-12.

8. The compound for the coating layer according to claim 1, The compound of chemical formula 1 is any one of the following compounds represented by chemical formulas: 。 9. An organic light-emitting element comprising a coating compound according to any one of claims 1 to 8.

10. The organic light-emitting element according to claim 9, The organic light-emitting element comprises: Electrode 1; The second electrode faces the first electrode. One or more organic layers are located inside the first electrode and the second electrode; and, A capping layer disposed outside one or more of the first electrode and the second electrode, comprising a capping layer compound as described in any one of claims 1 to 8.

11. The organic light-emitting element according to claim 10, characterized in that: The thickness of the covering layer is 100 to 2000. .

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

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