Organic light emitting element and method for manufacturing the same

Abstract

The present application provides an organic light emitting element having a light emitting layer with excellent orientation. The organic light emitting element of the present application forms a light emitting layer including a host material and a delayed fluorescence material on the surface of a base layer including a compound of the following general formula. X is O, S, N(R 9 ); R 1 ~ R 8 are a hydrogen atom, a deuterium atom, or a substituent; R 9 is a substituent; a benzene ring of the following general formula is fused with a benzofuran structure, a benzothiophene structure, or an indole structure, or R 6 is a carbazole group, a dibenzofuran group, or a dibenzothiophene group.

Description

Technical Field

[0001] This invention relates to an organic light-emitting element using delayed fluorescence material and a method for manufacturing the same. Background Technology

[0002] Research is actively underway to improve the luminous efficiency of organic light-emitting elements (OLEDs) and other organic light-emitting devices. In particular, research is being conducted on various methods to enhance luminous efficiency by developing and combining new electron transport materials, hole transport materials, host materials, and luminescent materials that constitute organic OLEDs. Research has also been found to utilize organic light-emitting elements with delayed fluorescence materials.

[0003] Delayed fluorescence materials are compounds that emit fluorescence upon returning to the ground state after a reverse intersystem crossing from the excited triplet state to the excited singlet state in the excited state. Because the fluorescence generated by this pathway is observed later than the fluorescence from the excited singlet state directly generated from the ground state (normal fluorescence), it is called delayed fluorescence. Here, for example, when a luminescent compound is excited by implantation into a support, since the generation probabilities of the excited singlet state and the excited triplet state are statistically 25%:75%, there is a limit to the improvement in luminescence efficiency if only fluorescence from the directly generated excited singlet state is used. On the other hand, because delayed fluorescence materials can also emit fluorescence from the excited triplet state via the aforementioned reverse intersystem crossing pathway, in addition to the excited singlet state, they can achieve higher luminescence efficiency compared to conventional delayed fluorescence materials.

[0004] As such delayed fluorescence materials, benzene derivatives having carbazole or other heteroaryl groups or diphenylamino and at least two cyano groups have been proposed, and it has been confirmed that high luminous efficiency has been obtained in organic EL elements using their benzene derivatives as the light-emitting layer (see Patent Document 1).

[0005] Furthermore, Non-Patent Document 1 reports that carbazole dibenzonitrile derivative (4CzTPN) is a thermally active delayed fluorescence material, and reports that high internal EL quantum efficiency is achieved by using an organic electroluminescent element based on this carbazole dibenzonitrile derivative.

[0006] On the other hand, it has been proposed that instead of using delayed fluorescence material as the luminescent material, it is used as an auxiliary dopant in the luminescent layer (see Patent Document 2). Here, it is described that luminescence efficiency is improved by adding a delayed fluorescence material having the lowest excitation singlet energy between the host material and the fluorescent luminescent material to the luminescent layer, in addition to the host material and the fluorescent luminescent material.

[0007] Previous technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-43541

[0010] Patent Document 2: Japanese Patent Application Publication No. 2015-179809

[0011] Non-patent literature

[0012] Non-patent literature 1: H. Uoyama, et al., Nature 492, 234 (2012) Summary of the Invention

[0013] The technical problem to be solved by the invention

[0014] As mentioned above, research is actively underway to improve the luminous efficiency of organic electroluminescent devices (OLEDs) by using delayed fluorescence materials in the emitting layer. To further enhance the luminous efficiency of OLEDs, it is desirable to improve the orientation of the luminescent material in the emitting layer. Therefore, it is desirable to improve the orientation in the emitting layer using delayed fluorescence materials, but previous studies on methods for improving orientation have not been extensive.

[0015] In this context, the inventors conducted in-depth research on organic light-emitting elements having a light-emitting layer containing a delayed fluorescence material, with the aim of improving the orientation of the light-emitting layer.

[0016] means for solving technical problems

[0017] As a result of in-depth research conducted to achieve the aforementioned objectives, the inventors discovered that by forming a light-emitting layer containing a delayed-fluorescence material on the surface of a substrate layer containing a compound with a specific structure, the orientation of the light-emitting material in the light-emitting layer can be improved. The present invention is based on this insight and specifically has the following structure.

[0018] [1] An organic light-emitting element comprising: a substrate layer and a light-emitting layer stacked on the surface of the substrate layer, wherein,

[0019] The light-emitting layer comprises a first organic compound and a second organic compound.

[0020] The second organic compound is a delayed fluorescence material having a lower minimum excitation singlet energy than the first organic compound.

[0021] The base layer comprises a compound represented by the following general formula (1).

[0022] General formula (1)

[0023] [Chemical Formula 1]

[0024]

[0025] In general formula (1), X represents O, S, or N(R). 9 ).

[0026] R 1 ~R 8 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent.

[0027] R 9 Indicates a substituent.

[0028] R 1 and R 2 R 2 and R 3 R 3 and R 4 R 5 and R 6 R 6 and R 7 R 7 and R 8 They can bond with each other to form a hydrocarbon ring, and the hydrogen atoms in the hydrocarbon ring can be replaced.

[0029] in,

[0030] R 1 and R 2 R 2 and R 3 or R 3 and R 4 They can bond with each other to form substituted or unsubstituted benzofuran structures, substituted or unsubstituted benzothiophene structures, or substituted or unsubstituted indole structures.

[0031] R 6 It can be a substituted or unsubstituted carbazoyl group, a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted dibenzothiophenyl group.

[0032] [2] According to the organic light-emitting element described in [1], wherein,

[0033] The fused ring structures contained in the compounds all have 5 or fewer rings.

[0034] [3] According to the organic light-emitting element described in [1] or [2], wherein,

[0035] The fused ring structures contained in the compounds all have 3 or fewer rings.

[0036] [4] The organic light-emitting element according to any one of [1] to [3], wherein,

[0037] X is N(R) 9 ), R 9The aryl group can be substituted or not.

[0038] [5] The organic light-emitting element according to any one of [1] to [4], wherein,

[0039] R 1 and R 2 R 2 and R 3 、or R 3 and R 4 They can form substituted or unsubstituted benzofuran structures by bonding with each other.

[0040] [6] The organic light-emitting element according to any one of [1] to [5], wherein,

[0041] When X is N(R) 9 And R 6 When the carbazoyl group is substituted or unsubstituted, the carbazoyl group is either substituted or unsubstituted carbazo-9-yl.

[0042] [7] The organic light-emitting element according to any one of [1] to [6], wherein,

[0043] The first organic compound includes a carbazole structure, a dibenzofuran structure, or a dibenzothiophene structure.

[0044] [8] The organic light-emitting element according to any one of [1] to [7], wherein,

[0045] The first organic compound is a compound represented by general formula (1), and may be the same as or different from the compound contained in the base layer.

[0046] [9] The organic light-emitting element according to any one of [1] to [8], wherein,

[0047] The second organic compound includes a carbazole structure, a dibenzofuran structure, or a dibenzothiophene structure.

[0048]

[10] The organic light-emitting element according to any one of [1] to [9], wherein,

[0049] The energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77 K of the second organic compound. ST It is below 0.3 eV.

[0050]

[11] The organic light-emitting element according to any one of [1] to

[10] , wherein,

[0051] The second organic compound is a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen and sulfur atoms.

[0052]

[12] The organic light-emitting element according to any one of [1] to

[11] , wherein,

[0053] The concentration of the second organic compound in the light-emitting layer is 5-50% by weight.

[0054]

[13] The organic light-emitting element according to any one of [1] to

[12] , wherein,

[0055] The light-emitting layer also includes a third organic compound having a lower minimum excitation singlet energy than the first organic compound and the second organic compound.

[0056]

[14] According to the organic light-emitting element described in

[13] , wherein,

[0057] The concentration of the third organic compound in the light-emitting layer is less than 3% by weight.

[0058]

[15] According to the organic light-emitting element described in

[13] or

[14] , wherein the third organic compound is a compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms, boron atoms, fluorine atoms, oxygen atoms and sulfur atoms.

[0059]

[16] The organic light-emitting element according to any one of [1] to

[15] is an organic electroluminescent element.

[0060]

[17] According to the organic light-emitting element described in

[16] , wherein,

[0061] The substrate layer is an electron blocking layer.

[0062]

[18] A method for manufacturing an organic light-emitting element, comprising a step of forming a light-emitting layer on the surface of a substrate layer, wherein,

[0063] The light-emitting layer comprises a first organic compound and a second organic compound.

[0064] The second organic compound is a delayed fluorescence material having a lower minimum excitation singlet energy than the first organic compound.

[0065] The base layer comprises a compound represented by the following general formula (1).

[0066] Invention Effects

[0067] In the organic light-emitting element of the present invention, the luminescent material comprising the delayed fluorescence material in the luminescent layer has high orientation. Therefore, the organic light-emitting element of the present invention has high luminous efficiency. Furthermore, according to the manufacturing method of the present invention, it is possible to easily manufacture an organic light-emitting element with high orientation of the luminescent material in the luminescent layer. Attached Figure Description

[0068] Figure 1 This is a schematic cross-sectional view showing an example of a layered structure of an organic electroluminescent element. Detailed Implementation

[0069] The present invention will be described in detail below. The descriptions of the constituent elements described below are sometimes based on representative embodiments or specific examples of the invention, but the invention is not limited to such embodiments or specific examples. Furthermore, in this document, the numerical range indicated by “~” means a range including the values ​​described before and after “~” as a lower and upper limit value. Also, in this document, “composed of ~” means only the composition described above “composed of”, excluding anything else. Furthermore, in the compounds used in the present invention, some or all of the hydrogen atoms present within the molecule can be replaced by deuterium atoms (…). 2 (H, Deuterium). In the chemical structural formulas described herein, the hydrogen atom is represented by H or its representation is omitted. For example, when the atom representing the carbon atom bonded to the ring skeleton of the benzene ring is omitted, it is assumed that H forms a carbon atom bond with the ring skeleton at the omitted position. In this document, the term "substituent" means an atom or group of atoms other than hydrogen and deuterium atoms. On the other hand, the term "substituted or unsubstituted" means that the hydrogen atom can be substituted by a deuterium atom or a substituent.

[0070] (Characteristics of organic light-emitting elements)

[0071] The organic light-emitting element of the present invention has a base layer comprising a compound represented by general formula (1) and a light-emitting layer stacked on the surface of the base layer. The light-emitting layer comprises a first organic compound and a second organic compound. Furthermore, the second organic compound is a delayed fluorescence material having a lower minimum excitation singlet energy than the first organic compound.

[0072] The light-emitting layer can be laminated either by directly covering the entire surface of one side of the substrate (one surface of the substrate) or by directly covering a portion thereof. Preferably, the entire light-emitting layer is laminated directly on the surface of the substrate.

[0073] According to the present invention, by forming a light-emitting layer comprising a second organic compound as a delayed fluorescence material on the surface of a substrate layer comprising a compound represented by general formula (1), the orientation of the second organic compound in the light-emitting layer can be improved. For example, compared to the case where no substrate layer is formed and the substrate layer is composed of the first organic compound of the light-emitting layer (which is not the compound represented by general formula (1)), when the substrate layer of the present invention is used, the orientation of the light-emitting layer formed on its surface can be improved. By using a compound represented by general formula (1) as the first organic compound, the orientation of the light-emitting layer can be further improved.

[0074] In addition to the first and second organic compounds, the luminescent layer may contain a third organic compound having a lower minimum excitation singlet energy than these compounds. In this case, according to the present invention, the third organic compound, as the luminescent material, also exhibits high orientation along with the second organic compound. Therefore, the present invention is effectively applicable not only to organic electroluminescent elements having a luminescent layer with a two-component system comprising the first and second organic compounds, but also to organic electroluminescent elements having a luminescent layer with a three-component system comprising the first, second, and third organic compounds. Furthermore, it is also applicable to organic electroluminescent elements having a luminescent layer with a four-component system or more comprising multiple third organic compounds.

[0075] In this paper, orientation can be evaluated by the S-value, which is an orientation parameter. The S-value, also known as the orientation value, is an indicator of the degree of orientation of the luminescent material within the luminescent layer. The larger the negative value (the smaller the numerical value), the higher the orientation. The S-value can be determined using the method described in Scientific Reports 2017, 7, 8405.

[0076] (Basal layer)

[0077] The base layer contains compounds represented by the following general formula (1).

[0078] General formula (1)

[0079] [Chemical Formula 2]

[0080]

[0081] In general formula (1), X represents O, S, or N(R) 9 X can be O. X can be S. S can be N(R) 9 ), R 9 Indicates a substituent. R 9Preferably, it is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group; more preferably, it is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group; and even more preferably, it is a group bonded by a benzene ring. Examples of substituents when aryl, heteroaryl, or alkyl groups are substituted include the following substituent group D. Preferably, R... 9 Examples include phenyl groups substituted with substituent group D and naphthyl groups substituted with substituent group D, as well as unsubstituted phenyl groups and unsubstituted naphthyl groups.

[0082] In general formula (1), R 1 ~R 8 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent. R 1 and R 2 R 2 and R 3 R 3 and R 4 R 5 and R 6 R 6 and R 7 R 7 and R 8 They can bond together to form hydrocarbon rings, and the hydrogen atoms of the hydrocarbon rings can be substituted. The hydrocarbon rings described herein can be aliphatic or aromatic. Other rings may be fused together in these aliphatic and aromatic hydrocarbon rings, or they may not be fused together. Aliphatic hydrocarbon rings are preferably 5- to 7-membered rings, more preferably 5- or 6-membered rings. Aromatic hydrocarbon rings are benzene rings. Preferred substituents for the hydrocarbon rings include the following substituent group D. R is also preferably used. 1 and R 2 R 2 and R 3 R 3 and R 4 R 5 and R 6 R 6 and R 7 R 7 and R 8 Compounds in which none of the compounds are bonded to each other.

[0083] In general formula (1), through R 1 and R 2 R 2 and R 3 、or R 3 and R 4 They bond to each other to form a substituted or unsubstituted benzofuran structure, a substituted or unsubstituted benzothiophene structure, or a substituted or unsubstituted indole structure (condition 1), or R 6The substituted or unsubstituted carbazoyl group, the substituted or unsubstituted dibenzofuranyl group, or the substituted or unsubstituted dibenzothiophenyl group (condition 2) can be satisfied simultaneously with conditions 1 and 2.

[0084] When the first condition is met, X can be 0 or S, but N(R) is preferred. 9 ).

[0085] If through R 1 and R 2 R 2 and R 3 、or R 3 and R 4 When they bond together to form substituted or unsubstituted benzofuran structures, the following skeleton is formed.

[0086] [Chemical Formula 3]

[0087]

[0088] In a preferred aspect of the invention, a compound having any of the following skeletons is selected.

[0089] [Chemical Formula 4]

[0090]

[0091] If through R 1 and R 2 R 2 and R 3 、or R 3 and R 4 When they bond together to form substituted or unsubstituted benzothiophene structures, the following skeleton is formed.

[0092] [Chemical Formula 5]

[0093]

[0094] In a preferred aspect of the invention, a compound having any of the following skeletons is selected.

[0095] [Chemical Formula 6]

[0096]

[0097] If through R 1 and R 2 R 2 and R 3 、or R 3 and R 4When these elements bond together to form substituted or unsubstituted indole structures, the following skeleton is formed. For a description and preferred range of R representing a substituent, please refer to the above description of R. 9 Description and preferred range.

[0098] [Chemical Formula 7]

[0099]

[0100] In a preferred aspect of the invention, a compound having any of the following skeletons is selected.

[0101] [Chemical Formula 8]

[0102]

[0103] The hydrogen atoms bonded in each of the above-mentioned skeletons can be replaced as substituents, preferably the following substituent group D.

[0104] When condition 2 is met, R 6 It can be a substituted or unsubstituted carbazolyl, a substituted or unsubstituted dibenzofuranyl, or a substituted or unsubstituted dibenzothiophenel.

[0105] When R 6 When the carbazol group is substituted or unsubstituted, it is preferably a substituted or unsubstituted carbazol-9-group. It can be a substituted or unsubstituted carbazol-1-group, or a substituted or unsubstituted carbazol-2-group, or a substituted or unsubstituted carbazol-3-group, or a substituted or unsubstituted carbazol-4-group, or a substituted or unsubstituted carbazol-9-group. In a preferred aspect of the invention, it is a substituted or unsubstituted carbazol-9-group. In particular, when X is N(R... 9 When ), it is preferred to use carbazole-9-yl, which may be substituted or unsubstituted.

[0106] When R 6 When the dibenzofuranyl group is substituted or unsubstituted, it can be dibenzofuran-1-yl, dibenzofuran-2-yl, dibenzofuran-3-yl, or dibenzofuran-4-yl. In a preferred aspect of the invention, it is dibenzofuran-3-yl, either substituted or unsubstituted.

[0107] When R 6 When the dibenzothiophene group is substituted or unsubstituted, it can be dibenzothiophene-1-yl, dibenzothiophene-2-yl, dibenzothiophene-3-yl, or dibenzothiophene-4-yl. In a preferred aspect of the invention, it is a substituted or unsubstituted dibenzothiophene-3-yl group.

[0108] Preferred substituents for carbazolyl, dibenzofuranyl, and dibenzothiophenel are the following substituent group D.

[0109] In a preferred aspect of the invention, the compound of general formula (1) that satisfies the second condition is represented by the following general formula (2).

[0110] General formula (2)

[0111] [Chemical Formula 9]

[0112]

[0113] In general formula (2), X represents O, S or N(R) 9 For an explanation of X and its preferred range, please refer to the corresponding description of general formula (1).

[0114] R via (2) 1 ~R 8 and R 10 ~R 16 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent. R 1 and R 2 R 2 and R 3 R 3 and R 4 R 7 and R 8 R 10 and R 11 R 11 and R 12 R 12 and R 13 R 14 and R 15 R 15 and R 16 R 16 and R 17 They can bond together to form a hydrocarbon ring, in which hydrogen atoms can be substituted. For a description of the hydrocarbon ring and preferred range, please refer to the corresponding description of the above general formula (1). R is also preferably used. 1 and R 2 R 2 and R 3 R 3 and R 4 R 7 and R 8 R 10 and R 11 R 11 and R 12 R 12 and R 13 R14 and R 15 R 15 and R 16 R 16 and R 17 Compounds in which none of the compounds are bonded to each other. R 1 ~R 8 and R 10 ~R 16 The substituents that can be used are preferably from the following group of substituents, D. For example, substituted or unsubstituted carbazolyl and substituted or unsubstituted aryl groups can be exemplified. As substituents, the following group of substituents, D, can be cited. In general formula (2), R is preferably selected. 3 R 12 and R 15 One to three of the constituent groups are substituents. In a preferred aspect of the invention, R 1 ~R 8 and R 10 ~R 16 In the middle, only select free R. 3 R 12 and R 15 One to three of the groups are replaced.

[0115] In a preferred aspect of the invention, the compound of general formula (1) that satisfies the second condition is represented by the following general formula (3).

[0116] General formula (3)

[0117] [Chemical Formula 10]

[0118]

[0119] In general formula (3), X and X' independently represent O, S or N(R) respectively. 9 For an explanation of X and X' and their preferred range, please refer to the description of X in general formula (1). When X is N(R) 9 When X' is used, it is preferred to be O or S.

[0120] R in general formula (3) 1 ~R 8 and R 21 ~R 27 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent. R 1 and R 2 R 2 and R 3 R 3 and R 4 R 7 and R 8 R 21 and R 22 R23 and R 24 R 24 and R 25 R 25 and R 26 They can bond together to form a hydrocarbon ring, in which hydrogen atoms can be substituted. For a description of the hydrocarbon ring and preferred range, please refer to the corresponding description of the above general formula (1). R is also preferably used. 1 and R 2 R 2 and R 3 R 3 and R 4 R 7 and R 8 R 21 and R 22 R 23 and R 24 R 24 and R 25 R 25 and R 26 Compounds in which none of the compounds are bonded to each other. R 1 ~R 8 and R 21 ~R 27 The substituents that can be used are preferably from the following group of substituents, D. For example, substituted or unsubstituted carbazolyl and substituted or unsubstituted aryl groups can be exemplified. As substituents, the following group of substituents, D, can be cited. In general formula (3), R is preferably selected. 3 and R 25 One or two of the constituent groups are substituents. In a preferred aspect of the invention, R 1 ~R 8 and R 21 ~R 27 In the middle, only select free R. 3 and R 25 One or two of the elements in the group are replaced.

[0121] The fused ring structures included in the compound represented by general formula (1) are preferably all 5 rings or less. That is, the compound represented by general formula (1) preferably does not include fused ring structures with more than 6 rings. The fused ring structures included in the compound represented by general formula (1) may all be 3 rings or less. Furthermore, the compound represented by general formula (1) may include at least one 5-ring fused ring structure. Furthermore, the compound represented by general formula (1) includes at least one 5-ring fused ring structure and at least one 3-ring fused ring structure, excluding fused ring structures with other numbers of rings. In a preferred aspect of the present invention, the compound represented by general formula (1) includes one 5-ring fused ring structure and one 3-ring fused ring structure, excluding fused ring structures other than those. In a preferred aspect of the present invention, the compound represented by general formula (1) includes two 5-ring fused ring structures and one 3-ring fused ring structure, excluding fused ring structures other than those. In a preferred aspect of the invention, the compound represented by general formula (1) comprises three fused ring structures of three rings, excluding fused ring structures other than those.

[0122] Here are specific examples of compounds represented by general formula (1).

[0123] [Chemical Formula 11]

[0124]

[0125] The base layer is preferably composed only of compounds represented by general formula (1), but may be a layer mainly comprising compounds represented by general formula (1). The concentration of compounds represented by general formula (1) in the base layer is preferably 90% by weight or more, more preferably 99% by weight or more, for example, 99.9% by weight or more, or 99.99% by weight or more. Examples of compounds other than those represented by general formula (1) included in the base layer include the lowest excitation singlet energy (E). S1 ) and the lowest excited triplet energy (E T1 Compounds that are close to those represented by general formula (1). Here, "close to" means an energy difference of less than 0.1 eV, preferably less than 0.05 eV, more preferably less than 0.03 eV, and even more preferably less than 0.01 eV.

[0126] The thickness of the substrate layer is preferably 1 nm or more, more preferably 3 nm or more, for example, it can be set to 5 nm or more or 10 nm or more. The thickness of the substrate layer is preferably less than 30 nm, more preferably less than 20 nm, for example, it can be set to less than 10 nm.

[0127] The thickness of the substrate layer is preferably smaller than the thickness of the light-emitting layer. The thickness of the substrate layer is preferably less than half the thickness of the light-emitting layer, more preferably less than one-third, and for example, less than one-quarter. Furthermore, it is preferably more than one-twentieth, for example, more than one-tenth.

[0128] (Materials constituting the light-emitting layer)

[0129] The luminescent layer comprises a first organic compound and a second organic compound. The second organic compound is a delayed-fluorescence material having a lower minimum excitation singlet energy than the first organic compound. In addition, the luminescent layer may contain a third organic compound having a lower minimum excitation singlet energy than both the first and second organic compounds.

[0130] The difference E between the lowest excited singlet state energies of organic compound 1 and organic compound 2 S1 (1)-E S1 (2) It can be set in a range of 0.3eV or above, 0.5eV or above, or 0.7eV or above, and can also be set in a range of 1.6eV or below, 1.3eV or below, or 0.9eV or below.

[0131] When using the third organic compound, the difference E between the lowest excited singlet state energies of the second and third organic compounds is... S1 (2)-E S1 (3) It can be set in a range of 0.03eV or above or 0.06eV, and can also be set in a range of 0.6eV or below, 0.3eV or below or 0.1eV.

[0132] The first organic compound preferably has a lower minimum excited triplet state energy at 77 K (absolute temperature scale) than the second and third organic compounds. While the lower minimum excited triplet state energy at 77 K (absolute temperature scale) is preferably higher than that of the second and third organic compounds, it can also be lower.

[0133] The concentration of the first organic compound contained in the luminescent layer is preferably higher than or equal to the concentration of the second organic compound. The concentration of the second organic compound in the luminescent layer is preferably 5% to 50% by weight.

[0134] When the light-emitting layer contains a third organic compound, the concentrations of the first, second, and third organic compounds in the light-emitting layer preferably satisfy the following relationship.

[0135] Conc(1)>Conc(2)>Conc(3)

[0136] Conc(1) represents the concentration of the first organic compound in the light-emitting layer, Conc(2) represents the concentration of the second organic compound in the light-emitting layer, and Conc(3) represents the concentration of the third organic compound in the light-emitting layer. In this invention, weight percent is used as the unit.

[0137] In the organic light-emitting element of the present invention, Conc(1) is preferably 30% by weight or more, and can be provided in the range of 50% by weight or more or 65% by weight or more, and can be provided in the range of 99% by weight or less, 85% by weight or less or 75% by weight or less.

[0138] In the organic light-emitting element of the present invention, Conc(2) is preferably 5% by weight or more, and can be provided in the range of 20% by weight or more or 30% by weight or more, and can be provided in the range of 50% by weight or less, 40% by weight or less or 35% by weight or less.

[0139] In the organic light-emitting element of the present invention, Conc(3) is preferably 5% by weight or less, more preferably 3% by weight or less. Conc(3) can be provided in the range of 1% by weight or less or 0.5% by weight or less, and can be provided in the range of 0.01% by weight or more, 0.1% by weight or more, or 0.3% by weight or more. Preferably, the following condition (d) is also satisfied.

[0140] Condition (d)Conc(2) / Conc(3)>5

[0141] Conc(2) / Conc(3) can be set in a range of 10 or more, 30 or more, or 50 or more, and can also be set in a range of 500 or less, 300 or less, or 100 or less.

[0142] (Organic Compound No. 1)

[0143] The first organic compound in the light-emitting layer of the organic light-emitting element used in this invention is selected from compounds having a lower minimum excitation singlet energy than the second organic compound. When the light-emitting layer also contains a third organic compound, the first organic compound is selected from compounds having a lower minimum excitation singlet energy than both the second and third organic compounds. The first organic compound preferably functions as a host material responsible for transport. Furthermore, the first organic compound preferably functions to confine the energy of the primarily luminescent compound within the light-emitting layer. Thus, the luminescent compound can efficiently convert the energy generated by the rebonding of intramolecular holes and electrons, as well as the energy received from the first organic compound, into light emission.

[0144] The first organic compound is preferably an organic compound that has hole transport and electron transport capabilities, prevents the luminescence from becoming too long-wavelength, and has a high glass transition temperature. Furthermore, in a preferred aspect of the invention, the first organic compound is selected from compounds that do not emit delayed fluorescence. The luminescence from the first organic compound is preferably less than 1% of the luminescence from the organic light-emitting element of the invention, more preferably less than 0.1%, for example, less than 0.01% and below the detection limit.

[0145] The first organic compound preferably does not contain metal atoms. For example, the first organic compound can be a compound composed of atoms selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, and sulfur atoms. For example, the first organic compound can be a compound composed of atoms selected from the group consisting of carbon, hydrogen, nitrogen, and oxygen atoms. For example, the first organic compound can be a compound composed of carbon, hydrogen, and nitrogen atoms.

[0146] The first organic compound is preferably a compound comprising a carbazole structure. Furthermore, the first organic compound is preferably a compound comprising a dibenzofuran structure. Additionally, the first organic compound is preferably a compound comprising a dibenzothiophene structure. In a preferred aspect of the invention, the first organic compound comprises two or more structures selected from the group consisting of a carbazole structure, a dibenzofuran structure, and a dibenzothiophene structure; for example, a compound comprising two structures or a compound having three structures can be selected. In a preferred aspect of the invention, the first organic compound is preferably a compound comprising a 1,3-phenylene structure. In a preferred aspect of the invention, the first organic compound is preferably a compound comprising a biphenylene structure. In a preferred aspect of the invention, a compound containing 5 to 8 benzene rings can be selected; for example, a compound with 5 benzene rings, a compound with 6 benzene rings, or a compound with 7 benzene rings can be selected.

[0147] The first organic compound can be a compound represented by general formula (1) or a compound not represented by general formula (1). As long as the first organic compound is a compound represented by general formula (1), the orientation of the luminescent material in the luminescent layer can be further improved. In one aspect of the invention, the first organic compound and the compound contained in the substrate layer have the same structure. In another aspect of the invention, the first organic compound is a compound represented by general formula (1), but has a different structure from the compound contained in the substrate layer. In this case, in one aspect of the invention, the molecular weight of the first organic compound is smaller than that of the compound represented by general formula (1) contained in the substrate layer, for example, less than 50 or more. Alternatively, in one aspect of the invention, the number of dibenzofuran structures contained in the first organic compound is greater than that of the compound represented by general formula (1) contained in the substrate layer. Alternatively, in one aspect of the invention, the number of carbazole structures contained in the first organic compound is less than that of the compound represented by general formula (1) contained in the substrate layer.

[0148] Hereinafter, preferred compounds that can be used as the first organic compound are given.

[0149] [Chemical Formula 12-1]

[0150]

[0151] [Chemical Formula 12-2]

[0152]

[0153] [Chemical Formula 12-3]

[0154]

[0155] (Second organic compound)

[0156] The second organic compound in the luminescent layer of the organic light-emitting element used in this invention is a delayed-fluorescence material having a lower minimum excitation singlet state energy than the first organic compound. When the luminescent layer contains a third organic compound, the second organic compound is a delayed-fluorescence material having a higher minimum excitation singlet state energy than the third organic compound. In this invention, "delayed-fluorescence material" refers to an organic compound that generates reverse intersystem crossing from the excited triplet state to the excited singlet state in the excited state and radiates fluorescence (delayed fluorescence) when returning from its excited singlet state to the ground state. In this invention, when the luminescence lifetime is measured using a fluorescence lifetime measurement system (such as the Hamamatsu Photonics KK stripe camera system), a material with an observed luminescence lifetime of 100 ns (nanoseconds) or more is called a delayed-fluorescence material. The second organic compound is a material capable of radiating delayed fluorescence; however, when used in the organic light-emitting element of this invention, radiating delayed fluorescence from the second organic compound is not necessary. The luminescence from the second organic compound is preferably less than 10% of the luminescence from the organic light-emitting element of the present invention, for example, less than 1%, less than 0.1%, less than 0.01%, and below the detection limit.

[0157] In the organic light-emitting element of the present invention, the second organic compound receives energy from the first organic compound in the excited singlet state and transitions to the excited singlet state. Furthermore, the second organic compound can receive energy from the first organic compound in the excited triplet state and transition to the excited triplet state. The difference (ΔE) between the excited singlet state energy and the excited triplet state energy of the second organic compound... ST The small size of the second organic compound in the excited triplet state allows for easy reverse intersystem crossing to the second organic compound in the excited singlet state. The second organic compound in the excited singlet state generated by these pathways fluoresces upon returning to the ground state. Furthermore, when a third organic compound is present in the luminescent layer, the second organic compound in the excited singlet state imparts energy to the third organic compound, causing the third organic compound to transition to the excited singlet state.

[0158] The difference ΔE between the lowest excited singlet energy and the lowest excited triplet energy at 77 K for the second organic compound. ST Preferably, it is 0.3 eV or less, more preferably 0.25 eV or less, even more preferably 0.2 eV or less, even more preferably 0.15 eV or less, further preferably 0.1 eV or less, even more preferably 0.07 eV or less, even more preferably 0.05 eV or less, even more preferably 0.03 eV or less, and especially preferably 0.01 eV or less.

[0159] If ΔE STBecause of the small size of the excitation triplet, it is easy for the excitation singlet state to transition from the reverse intersystem crossing due to the absorption of thermal energy. Therefore, the second organic compound functions as a thermally activated delayed fluorescence material. The heat emitted by the thermally activated delayed fluorescence material absorption device can relatively easily transition from the excitation triplet state to the excitation singlet state, thereby enabling its excitation triplet state to have good energy efficiency and contribute to luminescence.

[0160] The lowest excited singlet energy (E) of the compound in this invention S1 ) and the lowest excited triplet energy (E T1 ΔE is the value obtained through the following steps. ST To calculate E S1 -E T1 The value obtained is then calculated.

[0161] (1) Lowest excitation singlet energy (E S1 )

[0162] Prepare a thin film or toluene solution (concentration 10) of the compound to be measured. -5 A sample (mol / L) was used. The fluorescence spectrum of this sample was measured at room temperature (300 K). In the fluorescence spectrum, the vertical axis was set to emission, and the horizontal axis to wavelength. A tangent was drawn relative to the rising edge of the shorter wavelength side of the emission spectrum, and the wavelength value λedge [nm] at the intersection of the tangent and the horizontal axis was determined. The value obtained by converting this wavelength value into an energy value using the following conversion formula is set as E. S1 .

[0163] Conversion formula: E S1 [eV] = 1239.85 / λedge

[0164] Regarding the measurement of the emission spectrum in the embodiments described later, an LED light source (Thorlabs, Inc., M300L4) was used as the excitation source, and the measurement was performed using a detector (Hamamatsu Photonics KK, PMA-12 multichannel spectrometer C10027-01).

[0165] (2) Minimum Excitation Triplet Energy (E) T1 )

[0166] Liquid nitrogen will be used to achieve the lowest excitation singlet energy (E). S1The same sample used in the phosphorescence measurement was cooled to 77 K, and excitation light (300 nm) was irradiated onto the sample. Phosphorescence was measured using a detector. The emission 100 ms after excitation was defined as the phosphorescence spectrum. A tangent was drawn relative to the rising short-wavelength side of the phosphorescence spectrum, and the wavelength value λedge [nm] at the intersection of the tangent and the horizontal axis was determined. The value obtained by converting this wavelength value into an energy value using the following conversion formula is defined as E. T1 .

[0167] Conversion formula: E T1 [eV] = 1239.85 / λedge

[0168] The rising tangent on the short-wavelength side of the phosphorescence spectrum is drawn as follows. Consider the tangent lines at various points on the curve towards the long-wavelength side as the spectral curve moves from the short-wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side of the spectrum. The slope of this tangent line increases as the curve rises (i.e., as the vertical axis increases). The tangent line drawn at the point where this slope reaches its maximum value is taken as the rising tangent line for the short-wavelength side of the phosphorescence spectrum.

[0169] In addition, the maximum point of peak intensity with less than 10% of the maximum peak intensity of the spectrum is not included in the maximum value on the shortest wavelength side. The tangent line drawn at the point closest to the maximum value on the shortest wavelength side and where the slope value is the maximum value is set as the rising tangent line for the short wavelength side of the phosphorescence spectrum.

[0170] The second organic compound preferably does not contain metal atoms. For example, the second organic compound can be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, and sulfur atoms. For example, the second organic compound can be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and oxygen atoms. For example, the second organic compound can be a compound composed of carbon, hydrogen, deuterium, and nitrogen atoms. For example, the second organic compound can be a compound composed of carbon, hydrogen, and nitrogen atoms.

[0171] The second organic compound may preferably be a compound comprising a carbazole structure. Furthermore, the second organic compound may also preferably be a compound comprising a dibenzofuran structure. Additionally, the second organic compound may preferably be a compound comprising a dibenzothiophene structure.

[0172] Typical second organic compounds include compounds having a structure in which one or two acceptor groups and at least one donor group are bonded to a benzene ring. Preferably, the acceptor group is a heteroaromatic ring containing a cyano group or a triazine ring, etc., with nitrogen atoms as the ring skeleton. Preferably, the donor group is a substituted or unsubstituted carbazole-9-yl group. Examples include compounds in which three or more substituted or unsubstituted carbazole-9-yl groups are bonded to the benzene ring, or compounds in which the five-membered ring portion of each of a substituted or unsubstituted benzofuran ring, a substituted or unsubstituted benzothiophene ring, a substituted or unsubstituted indole ring, a substituted or unsubstituted indene ring, or a substituted or unsubstituted silynin ring is fused to at least one of the two benzene rings constituting the carbazole-9-yl group.

[0173] In this paper, the acceptor group is a group that has the property of attracting electrons relative to the ring bonded to the acceptor group, and can be selected, for example, from groups with a positive Hammett σp value. In this paper, the donor group is a group that has the property of donating electrons relative to the ring bonded to the donor group, and can be selected, for example, from groups with a negative Hammett σp value.

[0174] Here, "Hammett's σp value" is a value proposed by L.P. Hammett, which quantifies the effect of substituents on the reaction rate or equilibrium of para-substituted benzene derivatives. Specifically, it is the following equation that holds between the substituents in the para-substituted benzene derivative and the reaction rate constant or equilibrium constant:

[0175] log(k / k0)=ρσp

[0176] or

[0177] log(K / K0)=ρσp

[0178] The constant (σp) is specific to the substituents in the formula. In the above formula, k0 represents the rate constant of the benzene derivative without substituents, k represents the rate constant of the benzene derivative substituted with substituents, K0 represents the equilibrium constant of the benzene derivative without substituents, K represents the equilibrium constant of the benzene derivative substituted with substituents, and ρ represents the reaction constant determined by the type and conditions of the reaction. For explanations related to the "Hamette's σp value" in this invention and the values ​​of each substituent, please refer to the records related to the σp values ​​of Hansch, C. et.al., Chem. Rev., 91, 165–195 (1991).

[0179] Specific examples of acceptor groups, besides cyano groups, include the following groups. * indicates a bonding position, and "D" indicates a deuterium atom. In the following specific examples, the hydrogen atom may be substituted with an alkyl group, for example. Furthermore, the substituted or unsubstituted benzene ring may be further fused. Also, some or all of the hydrogen atoms may be substituted with deuterium atoms.

[0180] [Chemical Formula 13-1]

[0181]

[0182] [Chemical Formula 13-2]

[0183]

[0184] Specific examples of donor groups include the following groups. * indicates a bonding position, and "D" indicates a deuterium atom. In the following specific examples, the hydrogen atom may be substituted with an alkyl group, for example. Furthermore, the substituted or unsubstituted benzene ring may be further fused. Also, some or all of the hydrogen atoms may be substituted with deuterium atoms.

[0185] [Chemical Formula 14-1]

[0186]

[0187] [Chemical Formula 14-2]

[0188]

[0189] As the second organic compound, it is particularly preferable to use a compound represented by the following general formula (4) that exhibits delayed fluorescence.

[0190] General formula (4)

[0191] [Chemical Formula 15]

[0192]

[0193] In general formula (4), X 1 ~X 5 Represents N or CR. R represents a hydrogen atom, a deuterium atom, or a substituent. When X 1 ~X 5 When there are two or more CRs in X, these CRs can be the same or different. 1 ~X 5 At least one of them is a CD (where D represents a donor group). When X 1 ~X 5 When both are CR, Z represents the acceptor group.

[0194] Among the compounds represented by general formula (4), the compounds represented by general formula (5) are particularly preferred.

[0195] General formula (5)

[0196] [Chemical Formula 16]

[0197]

[0198] In general formula (5), X 1 ~X 5 Represents N or CR. R represents a hydrogen atom, a deuterium atom, or a substituent. When X 1 ~X 5 When there are two or more CRs in X, these CRs can be the same or different. 1 ~X 5 At least one of them is CD (where D represents the donor group).

[0199] In a preferred aspect of the invention, X 1 ~X 5 None of them are C-CN. That is, they are compounds having a structure with one cyano group and at least one donor group bonded to a benzene ring. In a preferred aspect of the invention, only X 2 Indicates C-CN, X 1 X 3 ~X 5 Not C-CN. That is, a compound having a structure in which at least one donor group is bonded to the benzene ring of isophthalonitrile. In another aspect of the invention, only X 3 Indicates C-CN, X 1 X 2 X 4 X 5 Not C-CN. That is, a compound having a structure in which at least one donor group is bonded to the benzene ring of terephthalonitrile.

[0200] In general formulas (4) and (5), X 1 ~X 5 It represents N or CR, but at least one is CD. X 1 ~X 5 The number of N in the equation is 0 to 4, for example, X can be exemplified. 1 and X 3 and X 5 X 1 and X 3 X 1 and X 4 X 2 and X 3 X 1 and X5 X 2 and X 4 Only X 1 Only X 2 Only X 3 The case where N is the number of elements. X 1 ~X 5 The number of CDs in the CD holder is 1 to 5, preferably 2 to 5. For example, X can be illustrated. 1 and X 2 and X 3 and X 4 and X 5 X 1 and X 2 and X 4 and X 5 X 1 and X 2 and X 3 and X 4 X 1 and X 3 and X 4 and X 5 X 1 and X 3 and X 5 X 1 and X 2 and X 5 X 1 and X 2 and X 4 X 1 and X 3 and X 4 X 1 and X 3 X 1 and X 4 X 2 and X 3 X 1 and X 5 X 2 and X 4 Only X 1 Only X 2 Only X 3 This is the case for CD. X 1 ~X 5 At least one of them can be CA. Here, A represents an acceptor group. X 1 ~X 5 The amount of CA in the formula is preferably 0 to 2, more preferably 0 or 1. As for A in CA, a heterocyclic aromatic group having a cyano group and an unsaturated nitrogen atom is preferably cited. Furthermore, X 1 ~X 5 They can be CD or CA independently.

[0201] When X 1 ~X 5 When two adjacent Rs represent CR, the two Rs can bond together to form a ring structure. The ring structure formed by bonding together can be an aromatic ring or an aliphatic ring, and can also contain heteroatoms. The ring structure can also be a fused ring with two or more rings. The heteroatoms mentioned herein are preferably atoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Examples of the formed ring structures include benzene rings, naphthalene rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, pyrrole rings, imidazole rings, pyrazole rings, imidazoline rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, cyclohexadiene rings, cyclohexene rings, cyclopentadiene rings, cycloheptane rings, cycloheptadiene rings, cycloheptene rings, furan rings, thiophene rings, naphthidine rings, quinoxaline rings, and quinoline rings. For example, rings formed by the fusion of multiple rings, such as phenanthrene rings or ditriphenylene rings, can be formed.

[0202] The donor group D in general formulas (4) and (5) is preferably, for example, the group represented by the following general formula (6).

[0203] General formula (6)

[0204] [Chemical Formula 17]

[0205]

[0206] In general formula (6), R 31 and R 32 Each of these can be independently represented as a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. R 31 and R 32 They can bond together to form a cyclic structure. L represents a single bond, a substituted or unsubstituted arylene, or a substituted or unsubstituted heteroarylene. Substituents that can be introduced into the arylene or heteroarylene of L can be groups including those represented by general formula (4) or general formula (5), or groups represented by general formulas (7) to (9) described later. These groups can be introduced up to the maximum number of substituents that can be introduced into L. Furthermore, when multiple substituents are introduced, these substituents can be the same or different from each other. * indicates the bonding position of the carbon atom (C) in general formula (4) or general formula (5) with the ring skeleton constituting the ring.

[0207] A substituent is a monovalent group that can be replaced by a hydrogen atom. For example, it can be selected from substituent group A, substituent group B, substituent group C, or substituent group D as described below.

[0208] The compound represented by general formula (6) is preferably a compound represented by any one of the following general formulas (7) to (9).

[0209] General formula (7)

[0210] [Chemical Formula 18]

[0211]

[0212] General formula (8)

[0213] [Chemical Formula 19]

[0214]

[0215] General formula (9)

[0216] [Chemical Formula 20]

[0217]

[0218] In general formulas (7) to (9), R 51 ~R 60 R 61 ~R 68 R 71 ~R 78 Each can be represented independently as a hydrogen atom, a deuterium atom, or a substituent. For a description and preferred range of substituents described herein, please refer to the description and preferred range of substituents in general formula (10) described later. R 51 ~R 60 R 61 ~R 68 R 71 ~R 78 It is also preferred that the substituents are each independently represented by any one of the general formulas (7) to (9) above. There is no particular limitation on the number of substituents in general formulas (7) to (9). It is also preferred that all of them are unsubstituted (i.e., hydrogen atoms or deuterium atoms). Furthermore, when there are two or more substituents in each of general formulas (7) to (9), these substituents may be the same or different. When there are substituents in general formulas (7) to (9), if it is general formula (7), then its substituents are preferably R. 52 ~R 59 If any of them is of general formula (8), then its substituent is preferably R. 62 ~R 67 If any of them is of general formula (9), then its substituent is preferably R. 72 ~R 77 Any one of them.

[0219] In general formula (9), X represents a divalent oxygen atom, sulfur atom, substituted or unsubstituted nitrogen atom, substituted or unsubstituted carbon atom, substituted or unsubstituted silicon atom, carbonyl group, or a divalent substituted or unsubstituted ethylene, substituted or unsubstituted vinylene, substituted or unsubstituted ortho-arylene, or substituted or unsubstituted ortho-hetero-arylene with a bonded chain length of 2 atoms. Regarding substituents, they can be selected, for example, from substituent group A, substituent group B, substituent group C, or substituent group D described below.

[0220] In general formulas (7) to (9), L 12 ~L 14 This indicates a single bond, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. Regarding L... 12 ~L 14 The description and preferred scope of the arylene or heteroarylene group represented by L can be found by referring to the description and preferred scope of the arylene or heteroarylene group represented by L. 12 ~L 14 Preferably, it is a single bond, substituted or unsubstituted arylene. The substituents of the arylene or heteroarylene described herein can be groups represented by general formulas (7) to (9). The groups represented by general formulas (7) to (9) can be introduced into L... 11 ~L 14 The maximum number of substituents. Furthermore, when multiple groups represented by general formulas (7) to (9) are introduced, these substituents may be the same as or different from each other. * indicates the bonding position of the carbon atom (C) in general formula (4) or general formula (5) with the carbon atom (C) constituting the ring skeleton.

[0221] In general formulas (7) to (9), R 51 and R 52 R 52 and R 53 R 53 and R 54 R 54 and R 55 R 55 and R 56 R 56 and R 57 R 57 and R 58 R 58 and R 59 R 59 and R 60 R 61 and R 62 R 62 and R 63 R 63 and R 64 R65 and R 66 R 66 and R 67 R 67 and R 68 R 71 and R 72 R 72 and R 73 R 73 and R 74 R 75 and R 76 R 76 and R 77 R 77 and R 78 They can bond together to form a ring structure. For an explanation and preferred examples of the ring structure, please refer to X in general formulas (4) and (5) above. 1 ~X 5 Explanation and preferred examples of the ring structure.

[0222] In the cyclic structure, the preferred structure is a fused structure of a substituted or unsubstituted benzofuran ring, a substituted or unsubstituted benzothiophene ring, a substituted or unsubstituted indole ring, a substituted or unsubstituted indene ring, or a substituted or unsubstituted silane-indene ring with at least one of the benzene rings of general formulas (7) to (9). More preferably, it is a structure represented by the following general formulas (8a) to (8f) fused with general formula (8).

[0223] [Chemical Formula 21]

[0224]

[0225] In general formulas (8a) to (8f), L 11 and L 21 ~L 26 Indicates a single bond or a divalent linker. Regarding L... 11 and L 21 ~L 26 For further explanation and preferred scope, please refer to the above L. 2 Description and preferred range.

[0226] In general formulas (8a) to (8f), R 41 ~R 110 Each can be used independently to represent a hydrogen atom or a substituent. R 41 and R 42 R 42 and R 43 R 43 and R 44 R 44 and R 45 R 45 and R 46R 46 and R 47 R 47 and R 48 R 51 and R 52 R 52 and R 53 R 53 and R 54 R 54 and R 55 R 55 and R 56 R 56 and R 57 R 57 and R 58 R 58 and R 59 R 59 and R 60 R 61 and R 62 R 62 and R 63 R 63 and R 64 R 65 and R 66 R 66 and R 67 R 67 and R 68 R 68 and R 69 R 69 and R 70 R 72 and R 73 R 73 and R 74 R 74 and R 75 R 75 and R 76 R 76 and R 77 R 77 and R 78 R 78 and R 79 R 79 and R 80 R 81 and R 82 R 82 and R 83 R 83 and R 84 R 84 and R 85 R 86 and R 87 R 87 and R 88 R88 and R 89 R 89 and R 90 R 91 and R 92 R 93 and R 94 R 94 and R 95 R 95 and R 96 R 96 and R 97 R 97 and R 98 R 99 and R 100 R 101 and R 102 R 102 and R 103 R 103 and R 104 R 104 and R 105 R 105 and R 106 R 107 and R 108 R 108 and R 109 R 109 and R 110 These rings can bond together to form a cyclic structure. The cyclic structure formed by bonding can be an aromatic ring or an aliphatic ring, and may also contain heteroatoms. The cyclic structure can also be a fused ring with two or more rings. The heteroatoms mentioned herein are preferably atoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Examples of the formed cyclic structures include benzene rings, naphthalene rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, pyrrole rings, imidazole rings, pyrazole rings, imidazole-line rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, cyclohexadiene rings, cyclohexene rings, cyclopentadiene rings, cycloheptane rings, cycloheptadiene rings, cycloheptene rings, furan rings, thiophene rings, naphthidine rings, quinoxaline rings, and quinoline rings. For example, rings formed by the fusion of multiple rings, such as phenanthrene rings or ditriphenylene rings, can be formed. The number of rings contained in the group represented by general formula (9) can be selected from the range of 3 to 5, or from the range of 5 to 7. The number of rings contained in the group represented by general formulas (8a) to (8f) can be selected from the range of 5 to 7, or from the range of five.

[0227] As R 41 ~R 110The substituents that can be used can be selected from groups of substituent group B, groups of substituent group C, or groups of substituent group D. Preferably, they are aryl groups with 6 to 10 carbon atoms substituted with an unsubstituted alkyl group having 1 to 10 carbon atoms or an unsubstituted alkyl group having 1 to 10 carbon atoms. In a preferred aspect of the invention, R... 41 ~R 110 It is an unsubstituted alkyl group having 1 to 10 hydrogen atoms or carbon atoms. In a preferred aspect of the invention, R 41 ~R 110 It is an unsubstituted aryl group having 6 to 10 hydrogen atoms or carbon atoms. In a preferred aspect of the invention, R 41 ~R 110 All are hydrogen atoms.

[0228] R in general formulas (8a) to (8f) 41 ~R 110 The bonded carbon atoms (the carbon atoms forming the ring framework) can be independently substituted with nitrogen atoms. That is, the CR atoms in general formulas (8a) to (8f) can be... 41 ~CR 110 Each nitrogen atom can be independently substituted with N. The number of nitrogen atoms substituted is preferably 0 to 4, more preferably 1 to 2, among the groups represented by general formulas (8a) to (8f). In one aspect of the invention, the number of nitrogen atoms substituted is 0. Furthermore, when two or more nitrogen atoms are substituted, it is preferable that the number of nitrogen atoms substituted in one ring is one.

[0229] In general formulas (8a) to (8f), X 1 ~X 6 This represents an oxygen atom, a sulfur atom, or NR. In one aspect of the invention, X... 1 ~X 6 X is an oxygen atom. In one aspect of the invention, X... 1 ~X 6 X is a sulfur atom. In one aspect of the invention, X... 1 ~X 6 NR. R represents a hydrogen atom or a substituent, preferably a substituent. As a substituent, a group from substituent group A, substituent group B, substituent group C, or substituent group D can be selected. For example, it is preferable to use an unsubstituted phenyl group substituted with a phenyl group substituted with one or more groups selected from the group consisting of alkyl and aryl groups.

[0230] In general formulas (8a) to (8f), * represents the bonding position.

[0231] In this invention, compounds represented by the following general formula (10) and exhibiting delayed fluorescence can be used, particularly preferably, as delayed fluorescence materials. In a preferred embodiment of this invention, the compound represented by general formula (10) can be used as the second organic compound.

[0232] General formula (10)

[0233] [Chemical Formula 22]

[0234]

[0235] In general formula (10), R 1 ~R 5 The 0 to 4 groups in the R group represent cyano groups. 1 ~R 5 At least one of them represents a substituted amino group, and the remaining R 1 ~R 5 It represents a hydrogen atom, a deuterium atom, or a substituent other than a cyano group or a substituted amino group.

[0236] The substituted amino group described herein is preferably a substituted or unsubstituted diarylamino group, wherein the two aryl groups constituting the substituted or unsubstituted diarylamino group can be linked to each other. Linkage can occur via a single bond (in which case a carbazole ring is formed), or via -O-, -S-, or -N(R) bonds. 6 )-、-C(R 7 (R) 8 )-、-Si(R 9 (R) 10 The linkage group is )- etc. Wherein, R 6 ~R 10 R represents a hydrogen atom, a deuterium atom, or a substituent. 7 and R 8 R 9 and R 10 They can be connected to each other to form a ring structure.

[0237] The substituted amino group can be R 1 ~R 5 Any one of them, for example, capable of R 1 and R 2 R 1 and R 3 R 1 and R 4 R 1 and R 5 R 2 and R 3 R 2 and R 4 R 1 and R 2 and R 3 R1 and R 2 and R 4 R 1 and R 2 and R 5 R 1 and R 3 and R 4 R 1 and R 3 and R 5 R 2 and R 3 and R 4 R 1 and R 2 and R 3 and R 4 R 1 and R 2 and R 3 and R 5 R 1 and R 2 and R 4 and R 5 R 1 and R 2 and R 3 and R 4 and R 5 Assuming it's a substituted amino group, etc. The cyano group can also be R. 1 ~R 5 Any one of them, for example, capable of R 1 R 2 R 3 R 1 and R 2 R 1 and R 3 R 1 and R 4 R 1 and R 5 R 2 and R 3 R 2 and R 4 R 1 and R 2 and R 3 R 1 and R 2 and R 4 R 1 and R 2 and R 5 R 1 and R 3 and R 4 R 1 and R 3 and R 5 R 2 and R3 and R 4 Let it be cyano, etc.

[0238] R is neither cyano nor substituted amino 1 ~R 5 This represents a hydrogen atom, a deuterium atom, or a substituent. Examples of substituents described herein include substituent group A. Preferred examples of substituents when the aryl group of the aforementioned diarylamino group is substituted include substituents from substituent group A, with cyano and substituted amino groups being further examples. Substituents selected from substituent group B, substituent group C, or substituent group D may be used instead of substituent group A.

[0239] For specific examples of the groups of compounds and compounds included in general formula (10), reference can be made to paragraphs 0008 to 0048 of WO2013 / 154064, paragraphs 0009 to 0030 of WO2015 / 080183, paragraphs 0006 to 0019 of WO2015 / 129715, paragraphs 0013 to 0025 of Japanese Patent Application Publication No. 2017-119663, and paragraphs 0013 to 0026 of Japanese Patent Application Publication No. 2017-119664, which are incorporated herein by reference as part of this document.

[0240] Furthermore, compounds represented by the following general formula (11) and exhibiting delayed fluorescence can be used, particularly preferably, as the delayed fluorescence material of the present invention. In a preferred embodiment of the present invention, the compound represented by general formula (11) can be used as the second organic compound.

[0241] General formula (11)

[0242] [Chemical Formula 23]

[0243]

[0244] In general formula (11), Y 1 Y 2 and Y 3 Any two atoms in the group represent nitrogen atoms, and the remaining one represents either a methine or a Y atom. 1 Y 2 and Y 3 The entire group represents nitrogen atoms. Z 1 and Z 2 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent. R 11 ~R 18 Preferably, each of the hydrogen atom, deuterium atom, or substituent is represented independently, R 11 ~R 18At least one of them is a substituted or unsubstituted aromatic amino group or a substituted or unsubstituted carbazole group. The benzene ring constituting the aromatic amino group and the benzene ring constituting the carbazole group can be respectively with R 11 ~R 18 Together they form single bonds or linking groups. Furthermore, compounds represented by general formula (11) contain at least two carbazole structures in their molecule. 1 Z 2 The substituents that can be used are, for example, selected from the following substituent group A, selected from the following substituent group B, selected from the following substituent group C, or selected from the following substituent group D. Furthermore, regarding R... 11 ~R 18 Specific examples of substituents that can be used for the aforementioned aromatic amino and carbazole groups include the substituents, cyano groups, substituted aromatic amino groups, and substituted alkyl amino groups in substituent group A below. Additionally, R... 11 and R 12 R 12 and R 13 R 13 and R 14 R 15 and R 16 R 16 and R 17 R 17 and R 18 They can bond together to form a ring structure.

[0245] Of the compounds represented by general formula (11), those represented by general formula (12) are particularly useful.

[0246] General formula (12)

[0247] [Chemical Formula 24]

[0248]

[0249] In general formula (12), Y 1 Y 2 and Y 3 Any two atoms in the group represent nitrogen atoms, and the remaining one represents either a methine or a Y atom. 1 Y 2 and Y 3 The entire group represents nitrogen atoms. Z 2 Represents a hydrogen atom, a deuterium atom, or a substituent. R 11 ~R 18 and R 21 ~R 28 Each can be used independently to represent a hydrogen atom, a deuterium atom, or a substituent. R 11 ~R 18 At least one of them and / or R 21 ~R 28At least one of them preferably represents a substituted or unsubstituted aromatic amino group or a substituted or unsubstituted carbazole group. The benzene ring constituting the aromatic amino group and the benzene ring constituting the carbazole group can be respectively associated with R 11 ~R 18 Or R 21 ~R 28 Together they form single bonds or linking groups. As Z... 2 Examples of substituents that can be used include substituents from substituent group A, substituents from substituent group B, substituents from substituent group C, and substituents from substituent group D. Furthermore, regarding R... 11 ~R 18 R 21 ~R 28 Specific examples of substituents that can be used for the aforementioned aromatic amino and carbazole groups include the substituents, cyano groups, substituted aromatic amino groups, and substituted alkyl amino groups in substituent group A below. Additionally, R... 11 and R 12 R 12 and R 13 R 13 and R 14 R 15 and R 16 R 16 and R 17 R 17 and R 18 R 21 and R 22 R 22 and R 23 R 23 and R 24 R 25 and R 26 R 26 and R 27 R 27 and R 28 They can bond together to form a ring structure.

[0250] For specific examples of the groups of compounds and compounds included in general formula (12), reference can be made to paragraphs 0020 to 0062 of WO2013 / 081088, which are incorporated herein by reference, or to the compounds described in Appl. Phys. Let, 98, 083302 (2011).

[0251] Furthermore, compounds represented by the following general formula (13) and exhibiting delayed fluorescence can be used, particularly preferably, as the delayed fluorescence material of the present invention.

[0252] General formula (13)

[0253] [Chemical Formula 25]

[0254]

[0255] In general formula (13), R 91 ~R 96 Each of the following groups independently represents a hydrogen atom, a deuterium atom, a donor group, or an acceptor group, wherein at least one is the donor group and at least two are the acceptor groups. The substitution positions of the at least two acceptor groups are not particularly limited, but it is preferable that they include two acceptor groups that are meta-relationed to each other. For example, when R... 91 When it is a donor group, at least R can be preferably exemplified. 92 and R 94 The structure of the acceptor group and at least R 92 and R 96 The structure of the acceptor group is as follows. The acceptor groups present in the molecule can be all the same or different from each other, but for example, all the same structure can be selected. The number of acceptor groups is preferably 2 to 3, for example, 2 can be selected. Furthermore, there can be more than two donor groups, and the donor groups can be all the same or different from each other. The number of donor groups is preferably 1 to 3, for example, only one or two. In addition, for the description and preferred range of donor groups and acceptor groups, refer to the corresponding description and preferred range of general formula (4). In particular, in general formula (13), the donor group is preferably represented by general formula (6), and the acceptor group is preferably represented by cyano or the following general formula (14).

[0256] General formula (14)

[0257] [Chemical Formula 26]

[0258]

[0259] In general formula (14), Y 4 ~Y 6 It can represent a nitrogen atom or a methine, but at least one of them is a nitrogen atom, preferably both of which represent nitrogen atoms. R 101 ~R 110 Each can be represented independently as a hydrogen atom, a deuterium atom, or a substituent, but at least one is preferably an alkyl group. For a description and preferred range of substituents described herein, please refer to the description and preferred range of substituents in the general formula (10). 15 The term L represents a single bond or linking group, and can be referred to the description and preferred scope of L in general formula (6). In a preferred aspect of the invention, L in general formula (14) 15 It is a single bond. * indicates the bonding position of the carbon atom (C) in the general formula (13) with the carbon atom (C) that makes up the ring skeleton.

[0260] Hereinafter, preferred compounds that can be used as the second organic compound are given. In the structural formulas of the following exemplary compounds, t-Bu represents tert-butyl.

[0261] [Chemical Formula 27-1]

[0262]

[0263] [Chemical Formula 27-2]

[0264]

[0265] [Chemical Formula 27-3]

[0266]

[0267] [Chemical Formula 27-4]

[0268]

[0269] [Chemical Formula 27-5]

[0270]

[0271] [Chemical Formula 27-6]

[0272]

[0273] [Chemical Formula 27-7]

[0274]

[0275] [Chemical Formula 27-8]

[0276]

[0277] [Chemical Formula 27-9]

[0278]

[0279] [Chemical Formula 27-10]

[0280]

[0281] [Chemical Formula 27-11]

[0282]

[0283] In the second organic compound, in addition to the above, known delayed fluorescence materials can also be appropriately combined and used. Furthermore, even unknown delayed fluorescence materials can be used.

[0284] Preferred delayed fluorescence materials include segments 0008–0048 and 0095–0133 from WO2013 / 154064, segments 0007–0047 and 0073–0085 from WO2013 / 011954, segments 0007–0033 and 0059–0066 from WO2013 / 011955, and segments 0008–0099–0099 from WO2013 / 011954. Paragraphs 071 and 0118–0133, paragraphs 0009–0046 and 0093–0134 of Japanese Patent Application Publication No. 2013-256490, paragraphs 0008–0020 and 0038–0040 of Japanese Patent Application Publication No. 2013-116975, paragraphs 0007–0032 and 0079–0084 of Japanese Patent Application Publication No. WO2013 / 133359, and paragraph 0007–0032 and 0079–0084 of Japanese Patent Application Publication No. WO2013 / 161437. Paragraphs 08 to 0054 and 0101 to 0121, paragraphs 0007 to 0041 and 0060 to 0069 of Japanese Patent Application Publication No. 2014-9352, paragraphs 0008 to 0048 and 0067 to 0076 of Japanese Patent Application Publication No. 2014-9224, paragraphs 0013 to 0025 of Japanese Patent Application Publication No. 2017-119663, and paragraphs 0013 to 0026 of Japanese Patent Application Publication No. 2017-119664. Compounds contained in the general formulas described in paragraphs 0012 to 0025 of Japanese Patent Application Publication No. 2017-222623, paragraphs 0010 to 0050 of Japanese Patent Application Publication No. 2017-226838, paragraphs 0012 to 0043 of Japanese Patent Application Publication No. 2018-100411, and paragraphs 0016 to 0044 of WO2018 / 047853, especially exemplary compounds capable of emitting delayed fluorescence.Furthermore, Japanese Patent Application Publication Nos. 2013-253121, WO2013 / 133359, WO2014 / 034535, WO2014 / 115743, WO2014 / 122895, WO2014 / 126200, WO2014 / 136758, and WO2014 / 133121 may be preferred. Communiqués, WO2014 / 136860, WO2014 / 196585, WO2014 / 189122, WO2014 / 168101, WO2015 / 008580, WO2014 / 203840, WO2015 / 002213, WO2015 / 016200, WO2015 Japanese Publication No. / 019725, WO2015 / 072470, WO2015 / 108049, WO2015 / 080182, WO2015 / 072537, WO2015 / 080183, Japanese Patent Application Publication No. 2015-129240, WO2015 / 129714, WO2015 / 12971 Materials that emit delayed fluorescence as described in Publications No. 5, WO2015 / 133501, WO2015 / 136880, WO2015 / 137244, WO2015 / 137202, WO2015 / 137136, WO2015 / 146541, and WO2015 / 159541. Furthermore, the aforementioned publications described in this paragraph are incorporated herein by reference as part of this document.

[0285] (The third organic compound)

[0286] The light-emitting layer of the organic light-emitting element of the present invention may contain a third organic compound. The third organic compound is a fluorescent material having a lower minimum excitation singlet energy than the first and second organic compounds. In a preferred aspect of the present invention, the third organic compound is a fluorescent material having a lower minimum excitation triplet energy than the first and second organic compounds. The third organic compound may be a delayed fluorescence material or a material that does not emit delayed fluorescence. When it is a delayed fluorescence material, the minimum excitation triplet energy of the third organic compound may be higher than that of the second organic compound. The third organic compound may be a compound with a higher or lower HOMO energy than the second organic compound. Furthermore, the third organic compound may be a compound with a higher or lower LUMO energy than the second organic compound. In a preferred aspect of the present invention, the third organic compound has lower HOMO and LUMO energies than the second organic compound.

[0287] In organic light-emitting elements using a third organic compound, the radiation originates from the fluorescence of the third organic compound. The emission from the third organic compound typically includes delayed fluorescence. The largest component of the emission from the organic light-emitting element of the present invention is the emission from the third organic compound. That is, the amount of emission from the third organic compound is the largest in the emission from the organic light-emitting element of the present invention. More than 70%, more than 90%, and more than 99% of the emission from the organic light-emitting element can be emission from the third organic compound. The third organic compound receives energy from the first organic compound in the excited singlet state, the second organic compound in the excited singlet state, and the second organic compound in the excited triplet state through a reverse intersystem crossing to become the excited singlet state, and transitions to the excited singlet state. Furthermore, in a preferred aspect of the present invention, the third organic compound receives energy from the second organic compound in the excited singlet state and the second organic compound in the excited triplet state through a reverse intersystem crossing to become the excited singlet state, and transitions to the excited singlet state. The excited singlet state of the resulting third organic compound emits fluorescence when it returns to the substrate state.

[0288] As a fluorescent material used as the third organic compound, there are no particular limitations as long as it can emit light by receiving energy from the first and second organic compounds. The emitted light may include any one of fluorescence, delayed fluorescence, and phosphorescence. It is preferable that the emitted light includes fluorescence or delayed fluorescence, and more preferably that the largest component of the emitted light from the third organic compound is fluorescence. In one aspect of the invention, the organic light-emitting element does not radiate phosphorescence or the amount of phosphorescence radiation is less than 1% of the fluorescence.

[0289] If the conditions of this invention are met, two or more third organic compounds can be used. For example, a desired color of emission can be achieved by simultaneously using two or more third organic compounds with different emission colors. Furthermore, monochromatic emission can be achieved using a single third organic compound.

[0290] In this invention, there is no particular limitation on the maximum emission wavelength of the compound that can be used as the third organic compound. Therefore, it is possible to appropriately select luminescent materials having a maximum emission wavelength in the visible region (380–780 nm), luminescent materials having a maximum emission wavelength in the infrared region (780 nm–1 mm), or compounds having a maximum emission wavelength in the ultraviolet region (e.g., 280–380 nm). Fluorescent materials having a maximum emission wavelength in the visible region are preferred. For example, luminescent materials with a maximum emission wavelength in the 380–780 nm region within the range of 380–570 nm can be selected, as can luminescent materials with a maximum emission wavelength in the range of 570–650 nm, luminescent materials with a maximum emission wavelength in the range of 650–700 nm, or luminescent materials with a maximum emission wavelength in the range of 700–780 nm.

[0291] In a preferred aspect of the invention, the compounds are selected and combined such that there is an overlap between the emission wavelength region of the second organic compound and the absorption wavelength region of the third organic compound. In particular, it is preferable that the edge of the short-wavelength side of the emission spectrum of the second organic compound overlaps with the edge of the long-wavelength side of the absorption spectrum of the third organic compound.

[0292] The third organic compound preferably does not contain any metal atoms other than boron atoms. For example, the third organic compound may be a compound that contains both boron and fluorine atoms. It may also be a compound that contains boron atoms but not fluorine atoms. Furthermore, it may not contain any metal atoms at all. For example, the third organic compound may be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, sulfur, fluorine, and boron atoms. For example, the third organic compound may be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, fluorine, and boron atoms. For example, the third organic compound may be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, sulfur, and boron atoms. For example, the third organic compound may be a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and boron atoms. For example, as a third organic compound, a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, and sulfur atoms can be selected. For example, as a third organic compound, a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and oxygen atoms can be selected. For example, as a third organic compound, a compound composed of carbon and hydrogen atoms can be selected.

[0293] As a third type of organic compound, examples include compounds with multiple resonance effects of boron and nitrogen atoms or compounds containing fused aromatic ring structures such as anthracene, pyrene, and perylene.

[0294] In a preferred aspect of the invention, a compound represented by the following general formula (15) is used as the third organic compound.

[0295] General formula (15)

[0296] [Chemical Formula 28]

[0297]

[0298] In the above general formula (15), Ar 1 ~Ar 3 Each ring is independently an aromatic or heteroaromatic ring, in which at least one hydrogen atom can be substituted, and the rings can be fused. When a hydrogen atom is substituted, it is preferably substituted by a group selected from the group consisting of deuterium, aryl, heteroaromatic, and alkyl, or a combination of two or more groups. Furthermore, when the rings are fused, it is preferably a benzene ring or a heteroaromatic ring (e.g., a furan ring, a thiophene ring, a pyrrole ring, etc.). a and R aEach substituent is represented independently, preferably a group selected from the group consisting of deuterium, aryl, heteroaryl, and alkyl, or a combination of two or more groups. R a and Ar 1 Ar 1 and Ar 2 Ar 2 and R a '、R a 'and Ar 3 Ar 3 and R a They can bond together to form a ring structure.

[0299] The compound represented by general formula (15) preferably contains at least one carbazole structure. For example, one of the benzene rings constituting the carbazole structure can be Ar. 1 The ring represented can also be an Ar ring, forming one of the benzene rings in the carbazole structure. 2 The ring represented can also be an Ar ring, forming one of the benzene rings in the carbazole structure. 3 The ring represented. Furthermore, the carbazole group can react with Ar. 1 ~Ar 3 It can be bonded to any one or more of Ar. For example, the substituted or unsubstituted carbazole-9-yl can be bonded to Ar. 3 The ring bond represented.

[0300] Anthracene, pyrene, perylene, and other fused aromatic ring structures can interact with Ar 1 ~Ar 3 Bonding. And, Ar 1 ~Ar 3 The ring represented can be one ring constituting a fused aromatic ring structure. Furthermore, R a and R a At least one of them can be a group having a fused aromatic ring structure.

[0301] Multiple skeletons represented by general formula (15) can exist in a compound. For example, a structure can have skeletons represented by general formula (15) bonded to each other via single bonds or linking groups. Furthermore, in the skeleton represented by general formula (15), a structure can be further added that exhibits multiple resonance effects by connecting benzene rings to each other through boron, nitrogen, oxygen, and sulfur atoms.

[0302] In a preferred aspect of the invention, a compound comprising the structure BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene: 4,4-difluoro-4-boron-3a,4a-diaza-s-indacene) is used as the third organic compound. For example, a compound represented by the following general formula (16) is used.

[0303] General formula (16)

[0304] [Chemical Formula 29]

[0305]

[0306] In general formula (16), R 1 ~R 7 Each can be independently a hydrogen atom, a deuterium atom, or a substituent. R 1 ~R 7 At least one of them is preferably a group represented by the following general formula (17).

[0307] General formula (17)

[0308] [Chemical Formula 30]

[0309]

[0310] In general formula (17), R 11 ~R 15 Each atom, deuterium atom, or substituent is represented independently, and * indicates the bonding position.

[0311] The group represented by general formula (17) can be R of general formula (16). 1 ~R 7 One, two, or three. Furthermore, it can be set to at least four, for example, four or five. In a preferred aspect of the invention, R... 1 ~R 7 One of them is a group represented by general formula (17). In a preferred aspect of the invention, at least R 1 R 3 R 5 R 7 It is a group represented by general formula (17). In a preferred aspect of the invention, only R 1 R 3 R 4 R 5 R 7 It is a group represented by general formula (17). In a preferred aspect of the invention, R 1 R 3 R 4 R 5 R 7 For the group represented by general formula (17), R 2 and R 4 It is a hydrogen atom, a deuterium atom, an unsubstituted alkyl group (e.g., 1 to 10 carbon atoms), or an unsubstituted aryl group (e.g., 6 to 14 carbon atoms). In one aspect of the invention, R 1 ~R7 All of them are groups represented by general formula (17).

[0312] In a preferred aspect of the invention, R 1 and R 7 The same. In a preferred aspect of the invention, R 3 and R 5 The same. In a preferred aspect of the invention, R 2 and R 6 The same. In a preferred aspect of the invention, R 1 and R 7 Same, R 3 and R 5 Same, and R 1 and R 3 They are different from each other. In a preferred aspect of the invention, R 1 R 3 R 5 R 7 The same. In a preferred aspect of the invention, R 1 and R 4 and R 7 Same, R 3 and R 5 Different. In a preferred aspect of the invention, R 3 and R 4 and R 5 Same, R 1 and R 7 Different. In a preferred aspect of the invention, R 1 R 3 R 5 R 7 Both are related to R 4 different.

[0313] R as general formula (17) 11 ~R 15 The substituents that can be used are, for example, selected from the following substituent group A, selected from the following substituent group B, selected from the following substituent group C, or selected from the following substituent group D. When a substituted amino group is selected as the substituent, a disubstituted amino group is preferred. The two substituents relative to the amino group are preferably independently substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted alkyl groups, and are particularly preferred to be substituted or unsubstituted aryl (diarylamino). The substituents that can be used as the two aryl groups of the diarylamino are, for example, selected from the following substituent group A, selected from the following substituent group B, selected from the following substituent group C, or selected from the following substituent group D. The two aryl groups of the diarylamino can be bonded to each other via a single bond or a linking group. For the linking group mentioned herein, please refer to R. 33 and R 34Explanation of the linking group. As a specific example of a diarylamino group, a substituted or unsubstituted carbazole-9-yl group can be used. As a substituted or unsubstituted carbazole-9-yl group, for example, L of the above general formula (9) can be cited. 11 It is a single-bonded group.

[0314] In a preferred aspect of the invention, only R of general formula (17) 13 As a substituent, R 11 R 12 R 14 R 15 It is a hydrogen atom. In a preferred aspect of the invention, only R of general formula (17) is used. 11 As a substituent, R 12 R 13 R 14 R 15 It is a hydrogen atom. In a preferred aspect of the invention, only R of general formula (17) is used. 11 and R 13 As a substituent, R 12 R 14 R 15 It is a hydrogen atom.

[0315] In general formula (16) R 1 ~R 7 In, R can include general formula (17). 11 ~R 15 All are groups consisting of hydrogen atoms (that is, phenyl). For example, R 2 R 4 R 6 It can be phenyl.

[0316] In general formula (16), R 8 and R 9 Preferably, each group is independently selected from one or more groups chosen from the group consisting of hydrogen, deuterium, halogen, alkyl (e.g., 1 to 40 carbon atoms), alkoxy (e.g., 1 to 40 carbon atoms), aryloxy (e.g., 6 to 30 carbon atoms), and cyano. In a preferred embodiment of the invention, R 8 and R 9 Same. In a preferred embodiment of the invention, R 8 and R 9 It is a halogen atom, and is particularly preferably a fluorine atom.

[0317] In one aspect of the invention, R of general formula (16) 1 ~R 9The total number of substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryloxy groups, and substituted or unsubstituted amino groups present in the compound is preferably three or more, for example, a compound with three groups or a compound with four groups can be used. More preferably, R in the general formula (16) 1 ~R 7 The total number of substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryloxy groups, and substituted or unsubstituted amino groups in the compound is preferably three or more, for example, a compound with three or four groups can be used. In this case, in R... 8 and R 9 Alkoxy, aryloxy, and amino groups may be absent. More preferably, R is in the form of general formula (16). 1 R 3 R 4 R 5 R 7 The total number of substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryloxy groups, and substituted or unsubstituted amino groups in the compound is preferably three or more, for example, a compound with three or four groups can be used. In this case, in R... 2 R 6 R 8 R 9 Alkoxy, aryloxy, and amino groups may be absent. In a preferred aspect of the invention, there are three or more substituted or unsubstituted alkoxy groups. In a preferred aspect of the invention, there are four or more substituted or unsubstituted alkoxy groups. In a preferred aspect of the invention, there is one or more substituted or unsubstituted alkoxy groups and two or more substituted or unsubstituted aryloxy groups. In a preferred aspect of the invention, there are two or more substituted or unsubstituted alkoxy groups and one or more substituted or unsubstituted amino groups. In a preferred aspect of the invention, in R... 1 R 4 R 7 The alkoxy group or the aryloxy group or the alkoxy group or the aryloxy group or the alkoxy group or the aryloxy group, respectively, are present. In a preferred aspect of the invention, in R... 1 R 4 R 7 The alkoxy groups are either substituted or unsubstituted.

[0318] In one aspect of the invention, R in general formula (16) 1 ~R 9The total number of substituents with a σp value less than -0.2 in the Hammett is three or more. Examples of substituents with a σp value less than -0.2 in the Hammett include methoxy (-0.27), ethoxy (-0.24), n-propoxy (-0.25), isopropoxy (-0.45), and n-butoxy (-0.32). On the other hand, fluorine (0.06), methyl (-0.17), ethyl (-0.15), tert-butyl (-0.20), n-hexyl (-0.15), and cyclohexyl (-0.15) are not substituents with a σp value less than -0.2 in the Hammett.

[0319] In one aspect of the invention, R is in a position where general formula (16) can be adopted. 1 ~R 9 The number of substituents in the compound having a σp value less than -0.2 is three, or can be four. More preferably, R in general formula (16) 1 ~R 7 The number of substituents in the Hammett compound with a σp value less than -0.2 is preferably three or more; for example, a compound with three or four substituents can be used. In this case, in R... 8 and R 9 The substituents in which the Hammett σp value is less than -0.2 may not exist. More preferably, R in general formula (16) is... 1 R 3 R 4 R 5 R 7 The number of substituents with a σp value less than -0.2 in the Hammett compound is preferably three or more; for example, a compound with three or four substituents can be used. In this case, in R... 2 R 6 R 8 R 9 Substituents with a σp value less than -0.2 for Hammett may not exist. In a preferred aspect of the invention, in R... 1 R 4 R 7 Substituents with σp values ​​less than -0.2 are present in the sample.

[0320] In this invention, the third organic compound may be a compound comprising a carbazole structure. Furthermore, the third organic compound may be a compound excluding any one of the carbazole, dibenzofuran, or dibenzothiophene structures.

[0321] Hereinafter, preferred compounds that can be used as a third organic compound are given. In the structural formulas of the following exemplary compounds, t-Bu represents tert-butyl.

[0322] [Chemical Formula 31-1]

[0323]

[0324] [Chemical Formula 31-2]

[0325]

[0326] [Chemical Formula 31-3]

[0327]

[0328] As derivatives of the above-described exemplary compounds, examples include compounds in which at least one hydrogen atom is replaced by a deuterium atom, alkyl group, aryl group, heteroaryl group, or diarylamino group.

[0329] Furthermore, the compound described in paragraphs 0220 to 0239 of WO2015 / 022974 may be used, in particular, as the third organic compound of the present invention.

[0330] The "alkyl" referred to herein can be any of the following: linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched moieties can be mixed. The number of carbon atoms in the alkyl group can be, for example, 1 or more, 2 or more, or 4 or more. The number of carbon atoms can be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 2-ethylhexyl, n-heptyl, isohexyl, n-octyl, isooctyl, n-nonyl, isonyl, n-decyl, isodexyl, cyclopentyl, cyclohexyl, and cycloheptyl. The alkyl group, as a substituent, can be further substituted with an aryl group.

[0331] The "alkenyl" group can be any of the following: linear, branched, or cyclic. Furthermore, two or more of the linear, cyclic, and branched groups can be mixed. The number of carbon atoms in the alkenyl group can be, for example, 2 or more, or 4 or more. The number of carbon atoms can also be 30 or less, 20 or less, 10 or less, 6 or less, or 4 or less. Specific examples of alkenyl groups include vinyl, propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, isopentenyl, n-hexenyl, isohexenyl, and 2-ethylhexenyl. The alkenyl group, as a substituent, can be further substituted with other substituents.

[0332] "Aryl" and "heteroaryl" can be monocyclic or fused rings composed of two or more rings. When fused rings are used, the number of fused rings is preferably 2 to 6, for example, 2 to 4. Specific examples of rings include benzene rings, pyridine rings, pyrimidine rings, triazine rings, naphthyl rings, anthracene rings, phenanthrene rings, triphenylene rings, quinoline rings, pyrazine rings, quinoxaline rings, and naphthidine rings. Specific examples of aryl or heteroaryl groups include phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 2-pyridyl, 3-pyridyl, and 4-pyridyl. "Arylidene" and "heteroaryl" can be groups in which the valence number in the description of aryl and heteroaryl is replaced from 1 to 2.

[0333] In this document, "substituent group A" means selected from hydroxyl, halogen (e.g., fluorine, chlorine, bromine, iodine), alkyl (e.g., 1-40 carbon atoms), alkoxy (e.g., 1-40 carbon atoms), alkylthio (e.g., 1-40 carbon atoms), aryl (e.g., 6-30 carbon atoms), aryloxy (e.g., 6-30 carbon atoms), arylthio (e.g., 6-30 carbon atoms), heteroaryl (e.g., 5-30 ring skeleton atoms), and heteroaryloxy (e.g., 5-30 ring skeleton atoms). A group consisting of one or more of the following groups: 30, heteroarylthio (e.g., 5 to 30 atoms in the ring skeleton), acyl (e.g., 1 to 40 carbon atoms), alkenyl (e.g., 1 to 40 carbon atoms), alkoxycarbonyl (e.g., 1 to 40 carbon atoms), aryloxycarbonyl (e.g., 1 to 40 carbon atoms), heteroaryloxycarbonyl (e.g., 1 to 40 carbon atoms), silyl (e.g., trialkylsilyl with 1 to 40 carbon atoms), and nitro.

[0334] In this document, "substituent group B" means a group selected from one or more of the group consisting of alkyl (e.g., 1 to 40 carbon atoms), alkoxy (e.g., 1 to 40 carbon atoms), aryl (e.g., 6 to 30 carbon atoms), aryloxy (e.g., 6 to 30 carbon atoms), heteroaryl (e.g., 5 to 30 atoms forming the ring skeleton), heteroaryloxy (e.g., 5 to 30 atoms forming the ring skeleton), and diarylamino (e.g., 0 to 20 carbon atoms).

[0335] In this document, “substituent group C” means a group selected from one or more of the group consisting of alkyl (e.g., 1 to 20 carbon atoms), aryl (e.g., 6 to 22 carbon atoms), heteroaryl (e.g., 5 to 20 cyclic skeleton atoms), and diarylamino (e.g., 12 to 20 carbon atoms).

[0336] In this document, "substituent group D" means a group selected from one or more groups composed of alkyl (e.g., 1 to 20 carbon atoms), aryl (e.g., 6 to 22 carbon atoms), and heteroaryl (e.g., 5 to 20 cyclic skeleton atoms).

[0337] (Emitting layer)

[0338] The light-emitting layer of the organic light-emitting element of the present invention comprises a first organic compound and a second organic compound. In addition to the first and second organic compounds, the light-emitting layer may comprise a third organic compound. The light-emitting layer can be configured such that, apart from these compounds, it does not contain compounds that perform charge or energy transfer or metallic elements other than boron. Furthermore, the light-emitting layer can also be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, boron, fluorine, oxygen, and sulfur atoms. For example, the light-emitting layer can be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, boron, fluorine, and oxygen atoms. For example, the light-emitting layer can be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, boron, fluorine, and sulfur atoms. For example, the luminescent layer can be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, and boron atoms. For example, the luminescent layer can be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, and sulfur atoms. For example, the luminescent layer can be composed solely of a compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, and nitrogen atoms. The luminescent layer may comprise a first organic compound consisting of atoms selected from the group consisting of carbon, hydrogen, nitrogen, and oxygen atoms; a second organic compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen, and sulfur atoms; and a third organic compound consisting of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, boron, oxygen, and sulfur atoms. Furthermore, the light-emitting layer may contain a first organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms and oxygen atoms, a second organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms and nitrogen atoms, and a third organic compound composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, deuterium atoms, nitrogen atoms and boron atoms.

[0339] The light-emitting layer can be formed by co-deposition of a first organic compound, a second organic compound, and any third organic compound, or by coating using a solution obtained by dissolving the first organic compound, the second organic compound, and any third organic compound. When forming the light-emitting layer by co-deposition of the first organic compound, the second organic compound, and the third organic compound, two or more of the first organic compound, the second organic compound, and the third organic compound can be pre-mixed and added to a crucible or the like as a deposition source. Co-deposition is then performed using this deposition source to form the light-emitting layer. For example, the first organic compound and the second organic compound can be pre-mixed to create a deposition source, and co-deposition is performed using this deposition source and a deposition source of the third organic compound to form the light-emitting layer.

[0340] (Layer structure of organic light-emitting elements)

[0341] The organic light-emitting element of the present invention has a base layer and a light-emitting layer stacked on the surface of the base layer.

[0342] The thickness of the light-emitting layer can be set to 5nm or more, 10nm or more, 20nm or more, or 40nm or more, and can be set to 80nm or less or 60nm or less.

[0343] For example, organic photoluminescent elements (organic PL elements) and organic electroluminescent elements (organic EL elements) can be exemplified as organic light-emitting elements of the present invention. Organic photoluminescent elements have a structure comprising at least a substrate layer and a light-emitting layer stacked on the surface of the substrate layer. Organic electroluminescent elements have at least an anode, a cathode, and an organic layer formed between the anode and the cathode. The organic layer comprises at least a substrate layer and a light-emitting layer stacked on the surface of the substrate layer; it may consist only of a substrate layer and an adjacent light-emitting layer, or it may have one or more organic layers in addition to the substrate layer and the adjacent light-emitting layer. Examples of organic layers other than the light-emitting layer include hole transport layers, hole injection layers, electron blocking layers, hole blocking layers, electron injection layers, electron transport layers, and exciton blocking layers. The hole transport layer can be a hole injection transport layer with hole injection function, and the electron transport layer can be an electron injection transport layer with electron injection function. In the present invention, a structure has a light-emitting layer stacked on the cathode-side surface of the substrate layer. The substrate layer may also serve as an electron blocking layer. The structure of a specific organic electroluminescent element is illustrated in... Figure 1 In. Figure 1 In the diagram, 1 represents the glass substrate, 2 represents the anode, 3 represents the hole injection layer, 4 represents the hole transport layer, 5 represents the base layer, 6 represents the light-emitting layer, 7 represents the hole blocking layer, 8 represents the electron transport layer, 9 represents the electron injection layer, and 10 represents the cathode.

[0344] When the organic light-emitting element of the present invention is a multi-wavelength light-emitting organic light-emitting element, the shortest wavelength light emission can be configured to include delayed fluorescence. Furthermore, the shortest wavelength light emission can also be configured to not include delayed fluorescence.

[0345] (Manufacturing method of organic light-emitting elements)

[0346] The organic light-emitting element of the present invention can be manufactured by stacking a light-emitting layer on the surface of a substrate layer. For example, in the case of manufacturing an organic electroluminescent element by stacking an organic layer on an anode, a substrate layer containing a compound represented by general formula (1) is formed on the anode or on an organic layer formed on the anode, and a light-emitting layer containing a first organic compound and a second organic compound is formed by stacking on the substrate layer.

[0347] There are no particular limitations on the method for forming the substrate layer and the light-emitting layer. A preferred method is vapor deposition. Furthermore, a coating method can also be used. The substrate layer and the light-emitting layer, which are adjacent to each other, can be formed continuously or intermittently. Continuous formation is preferred.

[0348] The organic light-emitting element (OLED) of the present invention can be easily manufactured using conventional OLED production lines (manufacturing equipment). In other words, in a conventional production line, the OLED of the present invention can be easily manufactured simply by using a compound represented by general formula (1) as the material for forming the substrate layer and changing the material for forming the light-emitting layer to include the first organic compound and the second organic compound. Therefore, the OLED of the present invention has the advantage of being able to be manufactured without changing or resetting the production line itself. Furthermore, after manufacturing the OLED of the present invention, it is possible to return to a production line for OLEDs other than those of the present invention by changing the materials used. Therefore, it can be implemented or reused economically in a short time, thus the OLED of the present invention has high industrial applicability.

[0349] In the manufacture of the organic light-emitting element of the present invention, the formation methods of other layers and structures are not particularly limited as long as the substrate layer and the light-emitting layer are formed in a manner that satisfies the conditions of the present invention. For example, the method may further include a step of forming electrodes such as an anode or a cathode, and may also further include a step of forming layers other than the substrate layer and the light-emitting layer. When the manufacturing method of the present invention is used, for example, in the manufacture of an organic electroluminescent element, the following steps can be performed: sequentially forming one or more organic layers on the anode, forming a substrate layer thereon, forming a light-emitting layer thereon, forming one or more organic layers thereon, and forming a cathode thereon. Furthermore, obvious modifications or additions can be made by those skilled in the art.

[0350] The following describes the components of an organic electroluminescent element and its layers other than the light-emitting layer.

[0351] Substrate:

[0352] In some embodiments, the organic electroluminescent element of the present invention is supported by a substrate, wherein the substrate is not particularly limited and can be any of those substrates commonly used in organic electroluminescent elements, such as those formed of glass, transparent plastic, quartz and silicon.

[0353] anode:

[0354] In some embodiments, the anode of the organic electroluminescent device is made of a metal, alloy, conductive compound, or a combination thereof. In some embodiments, the metal, alloy, or conductive compound has a high work function (above 4 eV). In some embodiments, the metal is Au. In some embodiments, the conductive transparent material can be selected from CuI, indium tin oxide (ITO), SnO2, and ZnO. In some embodiments, amorphous materials capable of forming transparent conductive films, such as IDIXO (In2O3-ZnO), are used. In some embodiments, the anode is a thin film. In some embodiments, the thin film is fabricated by vapor deposition or sputtering. In some embodiments, the film is patterned by photolithography. In some embodiments, when high precision (e.g., above about 100 μm) may not be required for the pattern, the pattern can be formed using a mask of the desired shape during vapor deposition or sputtering of the electrode material. In some embodiments, when a coating material (such as an organic conductive compound) can be applied, wet film formation methods, such as printing and coating, are used. In some embodiments, the transmittance of the anode is greater than 10% when the radiated light passes through it, and the sheet resistance of the anode is less than several hundred ohms per square meter. In some embodiments, the thickness of the anode is 10–1,000 nm. In some embodiments, the thickness of the anode is 10–200 nm. In some embodiments, the thickness of the anode varies depending on the material used.

[0355] cathode:

[0356] In some embodiments, the cathode is made of a metal (below 4 eV) (referred to as an electron-injecting metal), alloy, conductive compound, or combination thereof, with an electrode material having a low work function. In some embodiments, the electrode material is selected from sodium, sodium-potassium alloys, magnesium, lithium, magnesium-copper mixtures, magnesium-silver mixtures, magnesium-aluminum mixtures, magnesium-indium mixtures, aluminum-alumina (Al₂O₃) mixtures, indium, lithium-aluminum mixtures, and rare earth metals. In some embodiments, a mixture of the electron-injecting metal and a second metal is used, the second metal being a stable metal with a higher work function than the electron-injecting metal. In some embodiments, the mixture is selected from magnesium-silver mixtures, magnesium-aluminum mixtures, magnesium-indium mixtures, aluminum-alumina (Al₂O₃) mixtures, lithium-aluminum mixtures, and aluminum. In some embodiments, the mixture enhances electron-injection characteristics and resistance to oxidation. In some embodiments, the cathode is manufactured by forming the electrode material into a thin film using vapor deposition or sputtering. In some embodiments, the film resistivity of the cathode is below several hundred ohms per square meter. In some embodiments, the thickness of the cathode is in the range of 10 nm to 5 μm. In some embodiments, the thickness of the cathode is in the range of 50 to 200 nm. In some embodiments, either the anode or the cathode of the organic electroluminescent element is transparent or translucent in order to transmit the radiated light. In some embodiments, transparent or translucent electroluminescent elements enhance the luminous brightness.

[0357] In some embodiments, the cathode is formed using a conductive transparent material as described for the anode to form a transparent or translucent cathode. In some embodiments, the element comprises both a transparent or translucent anode and cathode.

[0358] Injection layer:

[0359] The injection layer is a layer located between the electrode and the organic layer. In some embodiments, the injection layer reduces the driving voltage and enhances the luminous intensity. In some embodiments, the injection layer includes a hole injection layer and an electron injection layer. The injection layer may be disposed between the anode and the luminescent layer or hole transport layer, and between the cathode and the luminescent layer or electron transport layer. In some embodiments, an injection layer is present. In some embodiments, an injection layer is not present.

[0360] Here are some examples of preferred compounds that can be used as hole injection materials.

[0361] [Chemical Formula 32]

[0362]

[0363] Next, preferred examples of compounds that can be used as electron injection materials will be given.

[0364] [Chemical Formula 33]

[0365]

[0366] Barrier layer:

[0367] A blocking layer is a layer capable of suppressing the diffusion of charges (electrons or holes) and / or excitons located in the light-emitting layer to the outside of the light-emitting layer. In some embodiments, an electron blocking layer is located between the light-emitting layer and the hole transport layer, and suppresses electrons from passing through the light-emitting layer toward the hole transport layer. In some embodiments, a hole blocking layer is located between the light-emitting layer and the electron transport layer, and suppresses holes from passing through the light-emitting layer toward the electron transport layer. In some embodiments, the blocking layer suppresses exciton diffusion to the outside of the light-emitting layer. In some embodiments, the electron blocking layer and the hole blocking layer constitute an exciton blocking layer. As used herein, the terms "electron blocking layer" or "exciton blocking layer" include layers that function as both electron blocking layers and exciton blocking layers.

[0368] Cavity blocking layer:

[0369] The hole blocking layer functions as an electron transport layer. In some embodiments, the hole blocking layer suppresses holes from reaching the electron transport layer while transporting electrons. In some embodiments, the hole blocking layer enhances the probability of rebonding between electrons and holes in the light-emitting layer. The material used for the hole blocking layer can be the same material described for the electron transport layer.

[0370] Here are some examples of preferred compounds that can be used in hole-blocking layers.

[0371] [Chemical Formula 34]

[0372]

[0373] Electron blocking layer:

[0374] Holes are transported by an electron blocking layer. In some embodiments, the electron blocking layer suppresses electrons from reaching the hole transport layer while transporting holes. In some embodiments, the electron blocking layer enhances the probability of rebonding between electrons and holes in the light-emitting layer. The material used for the electron blocking layer can be the same material described for the hole transport layer.

[0375] Below are specific examples of preferred compounds that can be used as electron blocking materials.

[0376] [Chemical Formula 35-1]

[0377]

[0378] [Chemical Formula 35-2]

[0379]

[0380] Exciton blocking layer:

[0381] An exciton blocking layer suppresses the diffusion of excitons generated via the rebonding of holes and electrons in the light-emitting layer into the electron transport layer. In some embodiments, the exciton blocking layer enables effective confinement of excitons within the light-emitting layer. In some embodiments, it enhances the luminous efficiency of the device. In some embodiments, the exciton blocking layer is adjacent to the light-emitting layer on either the anode side or the cathode side, or on both sides. In some embodiments, when the exciton blocking layer is on the anode side, the layer may be located between and adjacent to the hole transport layer and the light-emitting layer. In some embodiments, when the exciton blocking layer is on the cathode side, the layer may be located between and adjacent to the light-emitting layer and the cathode. In some embodiments, a hole injection layer, an electron blocking layer, or a similar layer is located between the anode and the exciton blocking layer, with the exciton blocking layer adjacent to the light-emitting layer on the anode side. In some embodiments, a hole injection layer, an electron blocking layer, a hole blocking layer, or a similar layer is located between the cathode and the exciton blocking layer, with the exciton blocking layer adjacent to the light-emitting layer on the cathode side. In some embodiments, the exciton blocking layer includes an excitation singlet energy and an excitation triplet energy, at least one of which is higher than the excitation singlet energy and excitation triplet energy of the luminescent material, respectively.

[0382] Hole transport layer:

[0383] The hole transport layer comprises a hole transport material. In some embodiments, the hole transport layer is a single layer. In some embodiments, the hole transport layer has multiple layers.

[0384] In some embodiments, the hole transport material has one of the characteristics of hole injection or transport and electron blocking. In some embodiments, the hole transport material is an organic material. In some embodiments, the hole transport material is an inorganic material. Examples of known hole transport materials that can be used in this invention include (but are not limited to) triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkyl derivatives, pyrazolene derivatives, dihydropyrazolone derivatives, phenylenediamine derivatives, aromatic amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrene-anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers (especially thiophene oligomers) or combinations thereof. In some embodiments, the hole transport material is selected from porphyrin compounds, aromatic tertiary amines, and styrene amine compounds. In some embodiments, the hole transport material is an aromatic tertiary amine compound. Specific examples of preferred compounds that can be used as hole transport materials are given below.

[0385] [Chemical Formula 36]

[0386]

[0387] Electron transport layer:

[0388] The electron transport layer comprises an electron transport material. In some embodiments, the electron transport layer is a single layer. In some embodiments, the electron transport layer has multiple layers.

[0389] In some embodiments, the electron transport material only needs to have the function of transporting electrons injected from the cathode into the light-emitting layer. In some embodiments, the electron transport material also functions as a hole-blocking material. Examples of electron transport layers that can be used in this invention include (but are not limited to) nitro-substituted fluorene derivatives, dibenzoquinone derivatives, thiopiperanoxide derivatives, carbodiimide, fluorenemethane derivatives, anthraquinone dimethane, anthrone derivatives, oxadiazole derivatives, azole derivatives, aziridine derivatives, or combinations thereof, or polymers thereof. In some embodiments, the electron transport material is a thiadiazole derivative or a quinoxaline derivative. In some embodiments, the electron transport material is a polymer material. Specific examples of preferred compounds that can be used as electron transport materials are given below.

[0390] [Chemical Formula 37]

[0391]

[0392] Furthermore, preferred examples of compounds that can be added to the various organic layers include, for instance, compounds that can be added as stabilizing materials.

[0393] [Chemical Formula 38]

[0394]

[0395] Preferred materials for use in organic electroluminescent devices are specifically exemplified, but the materials that can be used in this invention are not limited to the compounds exemplified below. Furthermore, even compounds exemplified as materials with specific functions can be reused as materials with other functions.

[0396] Device:

[0397] In some implementations, the light-emitting layer is incorporated into the device. Examples of devices include, but are not limited to, OLED bulbs, OLED lights, television screens, computer monitors, mobile phones, and tablet computers.

[0398] In some embodiments, the electronic device includes an OLED having an anode, a cathode, and at least one organic layer containing a light-emitting layer between the anode and the cathode.

[0399] In some embodiments, the compositions described herein can be incorporated into various photosensitive or photoactivated devices, such as OLEDs or photovoltaic devices. In some embodiments, the compositions can be suitable for facilitating charge transfer or energy transfer within the device and / or for use as hole transport materials. Examples of such devices include, for instance, organic light-emitting diodes (OLEDs), organic integrated circuits (OICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic photodetectors, organic photosensors, organic field-quench devices (O-FQDs), light-emitting electrochemical cells (LECs), or organic laser diodes (O-lasers).

[0400] Light bulb or lamp:

[0401] In some embodiments, the electronic device includes an OLED, the OLED comprising an anode, a cathode, and at least one organic layer comprising a light-emitting layer located between the anode and the cathode.

[0402] In some embodiments, the device includes OLEDs of different colors. In some embodiments, the device includes an array comprising combinations of OLEDs. In some embodiments, the combination of OLEDs is a combination of three colors (e.g., RGB). In some embodiments, the combination of OLEDs is a combination of colors that are not red, green, or blue (e.g., orange and yellow-green). In some embodiments, the combination of OLEDs is a combination of two, four, or more colors.

[0403] In some embodiments, the device is an OLED lamp, the OLED lamp comprising:

[0404] The circuit board has a first surface having a mounting surface and a second surface opposite thereto, and at least one opening is defined thereon;

[0405] At least one OLED is disposed on the mounting surface and has a structure in which the at least one OLED includes an anode, a cathode and at least one organic layer containing a light-emitting layer between the anode and the cathode and emits light.

[0406] Housing, used for circuit board; and

[0407] At least one connector is disposed at an end of the housing, and the housing and the connector define an encapsulation suitable for mounting to a lighting device.

[0408] In some embodiments, the OLED lamp includes multiple OLEDs mounted on a circuit board to emit light in multiple directions. In some embodiments, a portion of the light emitted in a first direction is deflected to be emitted in a second direction. In some embodiments, a reflector is used to deflect the light emitted in the first direction.

[0409] Monitor or screen:

[0410] In some embodiments, the light-emitting layer of the present invention can be used in a screen or display. In some embodiments, methods including (but not limited to) vacuum evaporation, deposition, vapor deposition, or chemical vapor deposition (CVD) are used to deposit the compounds involved in the present invention onto a substrate. In some embodiments, the substrate is a photographic plate structure suitable for double-sided etching, providing pixels with a unique aspect ratio. The screen (which may also be referred to as a mask) is used in methods for manufacturing OLED displays. The corresponding artwork pattern design promotes extremely steep and narrow tie-bars between pixels in the vertical direction and promotes large swept-bevel openings in the horizontal direction. This allows for tight patterning of pixels required for high-definition displays while optimizing chemical vapor deposition onto the TFT substrate.

[0411] Internal patterning of pixels allows for the construction of three-dimensional pixel openings with varying aspect ratios in both the horizontal and vertical directions. Furthermore, imaging "strips" or halftone circles are used within the pixel region to suppress etching in specific areas until these specific patterns are undercut and leave the substrate. At this point, all pixel regions are processed at the same etching rate, but the depth varies depending on the halftone pattern. Changing the size and spacing of the halftone patterns allows etching to be suppressed at different rates within the pixel, allowing for locally deeper etching required to form steep vertical bevels.

[0412] The preferred material for vapor deposition masks is invar steel. Invar steel is a metal alloy that is cold-rolled into long thin sheets in a steel mill. Invar steel cannot be used as a nickel mask for electrodeposition onto a spin mandrel. A suitable and low-cost method for forming opening regions within a vapor deposition mask is a wet chemical etching method.

[0413] In some embodiments, the screen or display pattern is a pixel matrix on a substrate. In some embodiments, the screen or display pattern is fabricated using lithography (e.g., photolithography and e-beam lithography). In some embodiments, the screen or display pattern is fabricated using wet chemical etching. In other embodiments, the screen or display pattern is fabricated using plasma etching.

[0414] Method for manufacturing the device:

[0415] OLED displays are typically manufactured by forming a large motherboard and then cutting the motherboard into unit panels. Generally, each unit panel on the motherboard is formed by: forming a thin-film transistor (TFT) including an active layer and source / drain electrodes on a substrate, coating a planarization film onto the TFT, and sequentially forming a pixel electrode, a light-emitting layer, a counter electrode, and an encapsulation layer, and then cutting it from the motherboard.

[0416] In another aspect of the present invention, a method for manufacturing an organic light-emitting diode (OLED) display is provided, the method comprising:

[0417] The process of forming a barrier layer on the substrate of the motherboard;

[0418] The process of forming multiple display units from unit board units on the barrier layer;

[0419] The process of forming an encapsulation layer on each of the display units of the unit board; and

[0420] The process of coating an organic film on the interface portion between the unit plates.

[0421] In some embodiments, the barrier layer is an inorganic film formed of, for example, SiNx, and the edge portions of the barrier layer are covered with an organic film formed of polyimide or acrylamide. In some embodiments, the organic film facilitates the gentle cutting of the motherboard into unit panels.

[0422] In some embodiments, the thin-film transistor (TFT) layer has a light-emitting layer, a gate electrode, and a source / drain electrode. Each of the plurality of display units may include a thin-film transistor (TFT), a planarization film formed on the TFT layer, and a light-emitting unit formed on the planarization film, wherein the organic film coated on the interface portion is formed of the same material as the planarization film and is formed at the same time as the planarization film is formed. In some embodiments, the light-emitting unit is connected to the TFT layer, with a passivation layer, a planarization film, and an encapsulation layer therebetween, and the encapsulation layer covers and protects the light-emitting unit. In some embodiments of the manufacturing method, the organic film neither contacts the display unit nor the encapsulation layer.

[0423] Each of the organic film and the planarization film may comprise either polyimide or acryloyl groups. In some embodiments, the barrier layer may be an inorganic film. In some embodiments, the substrate may be formed of polyimide. The method may further include mounting a carrier substrate formed of a glass material onto another surface of the substrate before forming the barrier layer on one surface of the substrate formed of polyimide, and separating the carrier substrate from the substrate before cutting along the interface portion. In some embodiments, the OLED display is a flexible display.

[0424] In some embodiments, the passivation layer is an organic film disposed on the TFT layer to cover the TFT layer. In some embodiments, the planarization film is an organic film formed on the passivation layer. In some embodiments, the planarization film is formed of polyimide or acrylamide, as in the case of an organic film formed on the edge portion of the barrier layer. In some embodiments, the planarization film and the organic film are formed simultaneously when manufacturing an OLED display. In some embodiments, the organic film may be formed on the edge portion of the barrier layer such that a portion of the organic film directly contacts the substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the edge portion of the barrier layer.

[0425] In some embodiments, the light-emitting layer has a pixel electrode, a counter electrode, and an organic light-emitting layer disposed between the pixel electrode and the counter electrode. In some embodiments, the pixel electrode is connected to the source / drain electrode of the TFT layer.

[0426] In some embodiments, when a voltage is applied to the pixel electrode via the TFT layer, an appropriate voltage is formed between the pixel electrode and the opposite electrode, thereby causing the organic light-emitting layer to emit light and forming an image. Hereinafter, the image forming unit having a TFT layer and light-emitting units will be referred to as a display unit.

[0427] In some embodiments, the encapsulation layer covering the display units and preventing external moisture penetration can be formed as a thin-film encapsulation structure having organic and inorganic films alternately stacked. In some embodiments, the encapsulation layer has a thin-film encapsulation structure having multiple thin films stacked. In some embodiments, the organic film coated on the interface portion is spaced apart from each of the plurality of display units. In some embodiments, the organic film is formed such that a portion of the organic film directly contacts the substrate, and the remaining portion of the organic film contacts the barrier layer while surrounding the edge portion of the barrier layer.

[0428] In one embodiment, the OLED display is flexible and uses a soft substrate formed of polyimide. In some embodiments, the substrate is formed on a carrier substrate formed of a glass material, and then the carrier substrate is separated.

[0429] In some embodiments, a barrier layer is formed on the surface of the substrate opposite to the carrier substrate. In one embodiment, the barrier layer is patterned according to the size of each unit plate. For example, while forming the substrate over the entire surface of the motherboard, the barrier layer is formed according to the size of each unit plate, thereby forming a groove at the interface portion between the unit plate barrier layers. Each unit plate can be cut along the groove.

[0430] In some embodiments, the manufacturing method further includes a step of cutting along the interface portion, wherein a groove is formed in the barrier layer, wherein at least a portion of an organic film is formed in the groove, and the groove does not penetrate into the substrate. In some embodiments, a TFT layer is formed for each unit panel, and a passivation layer (i.e., an inorganic film) and a planarization film (i.e., an organic film) are disposed on the TFT layer to cover the TFT layer. The groove at the interface portion is covered with an organic film, such as a polyimide or acrylamide, while a planarization film formed of, for example, polyimide or acrylamide is formed. This is to prevent cracking by allowing the organic film to absorb shocks generated when cutting each unit panel along the groove at the interface portion. That is, if the entire barrier layer is completely exposed without the organic film, the shock generated when cutting each unit panel along the groove at the interface portion is transferred to the barrier layer, thereby increasing the risk of cracking. However, in one embodiment, because the grooves at the interface portions between the barrier layers are covered with an organic film, and this organic film absorbs impacts that would otherwise be transferred to the barrier layers, each unit panel can be cut gently, and cracking in the barrier layers can be prevented. In one embodiment, the organic film covering the grooves at the interface portions is spaced apart from the planarization film. For example, if the organic film and the planarization film are connected as a single layer, the organic film and the planarization film are spaced apart from each other to separate the organic film from the display unit because external moisture may penetrate into the display unit through the planarization film and a portion of the residual organic film.

[0431] In some embodiments, a display unit is formed by forming light-emitting units, and an encapsulation layer is disposed on the display unit to cover it. Thus, after the motherboard is fully manufactured, a carrier substrate supporting the substrate is separated from the substrate. In some embodiments, when a laser beam is radiated toward the carrier substrate, the carrier substrate separates from the substrate due to the difference in thermal expansion coefficients between the carrier substrate and the substrate.

[0432] In some embodiments, the motherboard is cut into unit panels. In some embodiments, the motherboard is cut along the interface portion between the unit panels using a cutting machine. In some embodiments, because the grooves at the interface portion along which the motherboard is cut are covered with an organic film, the organic film absorbs impact during cutting. In some embodiments, cracking in the barrier layer can be prevented during cutting.

[0433] In some implementations, the method reduces the defect rate of the product and stabilizes its quality.

[0434] On the other hand, there is an OLED display having: a barrier layer formed on a substrate; a display unit formed on the barrier layer; an encapsulation layer formed on the display unit; and an organic film coated on the edge portion of the barrier layer.

[0435] Example

[0436] The features of the present invention will be further described in detail below with examples. The materials, processing contents, and processing steps shown below can be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limited by the specific examples shown below. Furthermore, the evaluation of luminescence performance was performed using a source meter (TEKTRONIX, INC.: 2400 series), a semiconductor parameter analyzer (Agilent Technologies Japan, Ltd.: E5273A), an optical power meter measuring device (Newport Corporation: 1930C), an optical spectrometer (Ocean Photonics: USB2000), a spectroradiometer (TOPCON CORPORATION: SR-3), and a streak camera (HamamatsuPhotonics KK: C4334 type).

[0437] (Example 1)

[0438] In Example 1, the variation of the S-value of the luminescent layer with respect to the material of the substrate layer was investigated.

[0439] A 10 nm thick substrate layer was formed by vapor deposition of U1-U5 or a comparative compound (H1) on a glass substrate. H1 and T60 were then co-deposited onto the substrate layer from different vapor deposition sources at a weight ratio of 65:35, resulting in a 40 nm thick emitting layer. The S value of T60 in the formed emitting layer was measured. The results are shown in Table 1.

[0440] The results in Table 1 show that, compared to a comparative example using a substrate layer containing the same material (H1) as 65% by weight of the first organic compound included in the light-emitting layer, the S value of the second organic compound in the light-emitting layer of the present invention, which uses a substrate layer composed of a compound represented by general formula (1), is smaller. This indicates that by using the compound represented by general formula (1) in the substrate layer, the orientation of the second organic compound in the light-emitting layer formed thereon is significantly improved.

[0441] [Table 1]

[0442] Substrate material S value H1 (Comparative Example) -0.18 U1 (This invention) -0.29 U2 (This invention) -0.28 U3 (This invention) -0.25 U4 (This invention) -0.24 U5 (This invention) -0.23

[0443] (Example 2)

[0444] In Example 2, it was investigated how the S value of the light-emitting layer changed by changing the combination of the substrate material and the first organic compound of the light-emitting layer.

[0445] As shown in Table 2, by changing the material of the base layer and the combination of the light-emitting layer and the first organic compound, a base layer and a light-emitting layer were formed on a glass substrate in the same manner as in Example 1. The S value of T60 in the formed light-emitting layer was measured. The results are shown in Table 2.

[0446] The results in Table 2 show that the orientation of the second organic compound in the light-emitting layer is further improved by not only making the base layer composed only of compounds represented by general formula (1), but also setting the first organic compound included in the light-emitting layer to be a compound represented by general formula (1).

[0447] [Table 2]

[0448] Substrate material The first organic compound of the light-emitting layer S value H1 (Comparative Example) H1 -0.18 U4 (This invention) U5 -0.33 U4 (This invention) U2 -0.25 U5 (This invention) U5 -0.28 U2 (This invention) U2 -0.22

[0449] (Example 3)

[0450] In Example 3, the relationship between the material of the substrate and the S-value of the emissive layer was studied when the second organic compound of the emissive layer was changed.

[0451] The second organic compound of the light-emitting layer was changed from T60 to T3, and the combination of the substrate material and the first organic compound of the light-emitting layer was changed as shown in Tables 3 and 4. The substrate and light-emitting layer were formed on a glass substrate in the same manner as in Example 1. However, the weight ratio of the first organic compound to the second organic compound of the light-emitting layer was set to 70:30. The S value of T3 in the formed light-emitting layer was measured. The results are shown in Tables 3 and 4.

[0452] The results in Tables 3 and 4 show that even when the second organic compound of the luminescent layer is changed to a different delayed fluorescence material, the orientation of the second organic compound of the luminescent layer formed thereon can be significantly improved by using the compound represented by general formula (1) in the substrate layer. Furthermore, it is shown that by also setting the first organic compound included in the luminescent layer to the compound represented by general formula (1), the orientation of the second organic compound of the luminescent layer can be further improved.

[0453] [Table 3]

[0454] Substrate material The first organic compound of the light-emitting layer S value H1 (Comparative Example) H1 -0.26 U4 (This invention) H1 -0.34 U5 (This invention) H1 -0.30

[0455] [Table 4]

[0456] Substrate material The first organic compound of the light-emitting layer S value U4 (This invention) U5 -0.39 U4 (This invention) U2 -0.40 U4 (This invention) U3 -0.41 U5 (This invention) U5 -0.39 U2 (This invention) U2 -0.40

[0457] [Chemical Formula 39]

[0458]

[0459] (Example 4)

[0460] In Example 4, organic electroluminescent elements with different substrate layers were fabricated and evaluated.

[0461] Vacuum deposition was performed on a glass substrate with an anode consisting of an indium tin oxide (ITO) film with a thickness of 100 nm, at a vacuum level of 1×10⁻⁶. -6 Pa is used to stack various thin films. First, a 10 nm thick HATCN layer is formed on ITO, and a 35 nm thick NPD layer is formed on it. Next, a 10 nm thick U4 layer is formed on it as a substrate layer, and then H1 and T3 are co-deposited on it from different evaporation sources at a weight ratio of 70:30, thereby forming a 40 nm thick light-emitting layer. In addition, a 10 nm thick HB1 layer is formed on it, and then HB1 and Liq are co-deposited on it from different evaporation sources at a weight ratio of 70:30 to form a 20 nm thick layer. In addition, Liq is formed to a thickness of 2 nm, and then aluminum (Al) is deposited to a thickness of 100 nm, thereby forming a cathode. Through the above steps, the organic electroluminescent device of the present invention is fabricated.

[0462] For comparison, a comparative organic electroluminescent element with a substrate composed of H1 was also fabricated.

[0463] By driving each element, a maximum emission wavelength of 484 nm was observed. The results of measuring the external quantum efficiency (EQE) and initial driving voltage of each element are shown in Table 5. The results in Table 5 show that by using the compound represented by general formula (1) in the base layer to improve the orientation of the second organic compound in the luminescent layer, the luminescence efficiency of the element is improved and the initial driving voltage is suppressed.

[0464] [Table 5]

[0465] Substrate material S value EQE (%) Initial drive voltage (V) H1 (Comparative Example) -O.26 17.0 5.01 U4 (This invention) -0.34 19.3 5.01

[0466] (Example 5)

[0467] In Example 5, an organic electroluminescent element different from the first organic compound of the light-emitting layer was fabricated and evaluated.

[0468] Except for changing the first organic compound, which forms the substrate layer from U4 and the light-emitting layers from H1 and U5 respectively, an organic electroluminescent element was fabricated using the same method as in Example 4. The S-value, external quantum efficiency (EQE), and initial driving voltage of each fabricated element are measured in Table 6, as in Example 4. The results in Table 6 show that by not only constituting the substrate layer solely with compounds represented by general formula (1), but also setting the first organic compound included in the light-emitting layer to a compound represented by general formula (1), the orientation of the second organic compound in the light-emitting layer is further improved, thereby increasing the luminous efficiency of the suppression element and suppressing the initial driving voltage.

[0469] [Table 6]

[0470] Substrate material The first organic compound of the light-emitting layer S value EQE (%) Initial drive voltage (V) U4 (This invention) H1 -0.30 24.1 3.6 U4 (This invention) U5 -0.39 25.2 3.5

[0471] (Example 6)

[0472] In Example 6, an organic electroluminescent element was fabricated in which a third organic compound, whose lowest excitation singlet energy is lower than that of the first organic compound and the second organic compound, was also contained in the light-emitting layer.

[0473] The organic electroluminescent element was fabricated in the same manner as in Example 4, except that 0.5% by weight of F1 was added to the light-emitting layer as a third organic compound and the concentration of the first organic compound was changed to 69.5% by weight.

[0474] The S-values ​​of the fabricated elements were measured in the same manner as in Example 4. The results showed that the element using H1 in the substrate layer had a S-value of -0.293, and the element using U4 in the substrate layer had a S-value of -0.344. Furthermore, the element using U4 as the substrate layer also had a lower initial driving voltage. The results demonstrate that by constructing the substrate layer with the compound represented by general formula (1), the orientation of the second organic compound in the light-emitting layer is improved, and the initial driving voltage is suppressed.

[0475] [Chemical Formula 40]

[0476]

[0477] Industrial availability

[0478] According to the present invention, by using a compound represented by general formula (1) in the substrate layer, the orientation of the luminescent material of the luminescent layer formed thereon can be improved. Therefore, an organic electroluminescent element with high luminous efficiency can be provided. Furthermore, according to the manufacturing method of the present invention, an organic light-emitting element with high orientation of the luminescent material of the luminescent layer can be easily manufactured. Therefore, the present invention has high industrial applicability.

[0479] Symbol Explanation

[0480] 1-Substrate, 2-Anode, 3-Hole injection layer, 4-Hole transport layer, 5-Base layer, 6-Light emission layer, 7-Hole blocking layer, 8-Electron transport layer, 9-Electron injection layer, 10-Cathode.

Claims

1. An organic light-emitting element comprising: a substrate layer and a light-emitting layer stacked on the surface of the substrate layer, wherein, The light-emitting layer comprises a first organic compound and a second organic compound. The second organic compound is a delayed fluorescence material having a lower minimum excitation singlet energy than the first organic compound. The base layer comprises a compound represented by the following general formula (1), General formula (1) [Chemical Formula 1] In general formula (1), X represents N(R) 9 ), R 1 ~R 8 Each of these groups independently represents a hydrogen atom, a deuterium atom, or a group selected from the group consisting of alkyl, aryl, and heteroaryl groups, or a combination of two or more groups. R 9 This indicates a heteroaryl group that has been substituted or not substituted, or a phenyl group that has been substituted with a heteroaryl group. in, R 1 and R 2 R 2 and R 3 Or R 3 and R 4 They can bond with each other to form substituted or unsubstituted benzofuran structures, or substituted or unsubstituted benzothiophene structures.

2. The organic light-emitting element according to claim 1, wherein, The fused ring structures contained in the compounds all have 5 or fewer rings.

3. The organic light-emitting element according to claim 1 or 2, wherein, The fused ring structures contained in the compounds all have 3 or fewer rings.

4. The organic light-emitting element according to claim 1 or 2, wherein, R 1 and R 2 R 2 and R 3 、or R 3 and R 4 They can form substituted or unsubstituted benzofuran structures by bonding with each other.

5. The organic light-emitting element according to claim 1 or 2, wherein, When R 6 When the carbazoyl group is substituted or unsubstituted, the carbazoyl group is either substituted or unsubstituted carbazo-9-yl.

6. The organic light-emitting element according to claim 1 or 2, wherein, The first organic compound includes a carbazole structure, a dibenzofuran structure, or a dibenzothiophene structure.

7. The organic light-emitting element according to claim 1 or 2, wherein, The first organic compound is a compound represented by general formula (1), and may be the same as or different from the compound contained in the base layer.

8. The organic light-emitting element according to claim 1 or 2, wherein, The second organic compound includes a carbazole structure, a dibenzofuran structure, or a dibenzothiophene structure.

9. The organic light-emitting element according to claim 1 or 2, wherein, The energy difference ΔE between the lowest excited singlet state and the lowest excited triplet state at 77 K of the second organic compound. ST It is below 0.3 eV.

10. The organic light-emitting element according to claim 1 or 2, wherein, The second organic compound is a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, oxygen and sulfur atoms.

11. The organic light-emitting element according to claim 1 or 2, wherein, The concentration of the second organic compound in the light-emitting layer is 5 to 50% by weight.

12. The organic light-emitting element according to claim 1 or 2, wherein, The light-emitting layer also includes a third organic compound having a lower minimum excitation singlet energy than the first organic compound and the second organic compound.

13. The organic light-emitting element according to claim 12, wherein, The concentration of the third organic compound in the light-emitting layer is less than 3% by weight.

14. The organic light-emitting element according to claim 12, wherein, The third organic compound is a compound composed of atoms selected from the group consisting of carbon, hydrogen, deuterium, nitrogen, boron, fluorine, oxygen, and sulfur atoms.

15. The organic light-emitting element according to claim 1 or 2, wherein it is an organic electroluminescent element.

16. The organic light-emitting element according to claim 15, wherein, The substrate layer is an electron blocking layer.

17. A method for manufacturing an organic light-emitting element, comprising a step of forming a light-emitting layer on the surface of a substrate layer, wherein, The light-emitting layer comprises a first organic compound and a second organic compound. The second organic compound is a delayed fluorescence material having a lower minimum excitation singlet energy than the first organic compound. The base layer comprises a compound represented by the following general formula (1), General formula (1) [Chemical Formula 2] In general formula (1), X represents N(R) 9 ), R 1 ~R 8 Each of these groups independently represents a hydrogen atom, a deuterium atom, or a group selected from the group consisting of alkyl, aryl, and heteroaryl groups, or a combination of two or more groups. R 9 This indicates a heteroaryl group that has been substituted or not substituted, or a phenyl group that has been substituted with a heteroaryl group. R 1 and R 2 R 2 and R 3 Or R 3 and R 4 They can bond with each other to form substituted or unsubstituted benzofuran structures, or substituted or unsubstituted benzothiophene structures.

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