Organic electroluminescent element

Abstract

An organic EL element using the compound represented by general formula (1) according to the present invention can be an organic EL element having high luminous efficiency and a long life. A compound for an organic electroluminescent element is represented by general formula (1). Here, Ad is an adamantyl group represented by general formula (2). X independently represents N, or CR1, at least one X represents N. R1 independently represents hydrogen or the like; ar1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6-18 carbon atoms, or the like; r independently represents a substituted or unsubstituted aromatic heterocyclic group having 3-17 carbon atoms, or the like; l1 and L2 each independently represent a direct bond or the like; and a represents a substitution number and independently represents an integer of 0-4. And b-f each represents a substitution number and independently represents an integer of 0-4. Wherein b + c + d + e + f is greater than or equal to 1.

Description

Technical Field

[0001] The present invention relates to a compound, a material for an organic electroluminescent device, and an organic electroluminescent device (also referred to as an organic EL device). Background Art

[0002] By applying voltage to an organic electroluminescence (EL) element, holes are injected into the light-emitting layer from the anode and electrons are injected into the light-emitting layer from the cathode. Moreover, in the light-emitting layer, the injected holes recombine with electrons to generate excitons. At this time, according to the statistical law of electron spin, singlet excitons and triplet excitons are generated in a ratio of 1:3. Regarding organic EL elements of the fluorescent type using luminescence generated by singlet excitons, it is believed that the limit of the internal quantum efficiency is 25%. On the other hand, it is known that organic EL elements of the phosphorescent type using luminescence generated by triplet excitons can increase the internal quantum efficiency to 100% when intersystem crossing is efficiently performed from singlet excitons.

[0003] However, for phosphorescent organic EL elements, extending their lifespan has become a technical challenge.

[0004] Furthermore, high-efficiency organic EL devices that utilize delayed fluorescence are currently being developed. For example, Patent Document 1 discloses an organic EL device that utilizes the triplet-triplet fusion (TTF) mechanism, one of the mechanisms of delayed fluorescence. The TTF mechanism utilizes the phenomenon of generating singlet excitons through the collision of two triplet excitons, and is believed to theoretically increase the internal quantum efficiency to 40%. However, compared to phosphorescent organic EL devices, the efficiency is low, and therefore further efficiency improvements are required.

[0005] On the other hand, Patent Document 2 discloses an organic EL element that utilizes the Thermally Activated Delayed Fluorescence (TADF) mechanism. The TADF mechanism utilizes the following phenomenon: in a material with a small energy difference between the singlet and triplet energy levels, reverse intersystem crossing from triplet excitons to singlet excitons occurs; it is believed that the internal quantum efficiency can be increased to 100% in theory. However, as with phosphorescent light-emitting elements, further improvement in lifetime characteristics is required, especially in organic EL elements that emit blue light. More specifically, polycyclic aromatic compounds that emit blue light using the TADF mechanism have low tolerance to holes and electrons. Therefore, it is difficult to ensure a device life that can withstand practical use in organic EL elements used in combination with previously known hosts. Not only is it required to improve the dopant, but also to improve the lifetime characteristics, including the development of host materials with high tolerance to holes and electrons.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: WO2010 / 134350

[0009] Patent Document 2: WO2011 / 070963

[0010] Patent Document 3: WO2015 / 102118

[0011] Patent Document 4: WO2017 / 115833

[0012] Patent Document 5: WO2018 / 212169

[0013] Patent Document 6: WO2018 / 181188

[0014] Patent Document 7: WO2020 / 040298

[0015] Patent Document 8: Japanese Patent Application Laid-Open No. 2020-120096

[0016] Patent Document 9: WO2008 / 117826

[0017] Patent Document 10: CN112778278

[0018] Patent Document 11: WO2022 / 027992

[0019] Patent Document 12: WO2021 / 228111

[0020] Patent Document 4 discloses an organic EL device in which two host materials represented by the following compounds and a TADF material are contained in a light-emitting layer as light-emitting dopants.

[0021] [Chemistry 1]

[0022]

[0023] Patent Documents 3 and 5 disclose an organic EL device using a TADF material containing a polycyclic aromatic compound represented by the following compound as a light-emitting dopant.

[0024] [Chemistry 2]

[0025]

[0026] Patent Documents 6 and 7 disclose an organic EL device in which a boron compound, a TADF material, and the following carbazole compound are mixed and used in a light-emitting layer.

[0027] [Chemistry 3]

[0028]

[0029] Patent Document 8 discloses an organic EL device in which a boron compound a7 described below is mixed with a nitrogen-containing six-membered ring compound a8 and a carbazole compound a9 for use in a light-emitting layer.

[0030] [Chemistry 4]

[0031]

[0032] Patent Document 9 discloses a phosphorescent organic EL device using, as a host material, a compound in which a nitrogen-containing six-membered ring represented by the following compound is linked to carbazole.

[0033] [Chemistry 5]

[0034]

[0035] Patent Document 10 discloses an organic EL device using, as a host material, a compound in which an adamantyl group is further linked to a skeleton composed of a nitrogen-containing six-membered ring linked to carbazole, as typified by the following compound.

[0036] [Chemistry 6]

[0037]

[0038] Patent Document 11 discloses an organic EL device using, as a host material, a compound in which a cyano group and an adamantyl group are linked to a nitrogen-containing six-membered ring, as typified by the following compound.

[0039] [Chemistry 7]

[0040]

[0041] Patent Document 12 discloses an organic EL device using, as a host material, a compound in which dibenzofuran represented by the following compound is linked to an adamantyl group.

[0042] [Chemistry 8]

[0043]

[0044] However, any of the documents still have room for improvement in terms of organic EL devices exhibiting sufficient lifespan characteristics. Summary of the Invention

[0045] Problems to be solved by the invention

[0046] In order to apply organic EL elements to display elements or light sources such as flat panel displays, it is necessary to improve the luminous efficiency of the elements while ensuring sufficient stability during driving. The object of the present invention is to provide a practically useful organic EL element with high efficiency and long life, and a compound suitable for the same.

[0047] Technical means to solve the problem

[0048] The present invention relates to a material for an organic electroluminescent device, comprising a compound represented by the following general formula (1).

[0049] [Chemistry 9]

[0050]

[0051] Here, Ad is an adamantyl group represented by the following general formula (2), and preferably represented by the following general formula (3).

[0052] [Chemistry 10]

[0053]

[0054] Here, * represents a bonding point with the general formula (1).

[0055] X independently represents N, or CR 1 , at least one X represents N, preferably all X represent N.

[0056] R 1independently represents hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups.

[0057] Ar 1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups, Ar 1 Preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 11 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 11 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups. 1 More preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 11 carbon atoms, or a substituted or unsubstituted linked aromatic group composed of two to five of these aromatic groups linked together.

[0058] R independently represents deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0059] L 1 , and L 2 Each independently represents a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups, L 1 and L 2 Preferably, each independently represents a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, and more preferably represents a direct bond.

[0060] a represents the number of substitutions and independently represents an integer from 0 to 4, and preferably all a's are 0. b to f represent the number of substitutions and independently represent an integer from 0 to 4. b+c+d+e+f≧1 is satisfied, preferably b+c+d≧1, and more preferably b+c+d+e+f≧2 is satisfied.

[0061] The glass transition temperature (Tg) of the compound for an organic electroluminescent device represented by the general formula (1) of the present invention is preferably 135° C. or higher, more preferably 140° C. or higher.

[0062] The organic electroluminescent element of the present invention preferably comprises one or more light-emitting layers between opposing anodes and cathodes, wherein at least one light-emitting layer comprises a host selected from the compound represented by the general formula (1) and a light-emitting dopant comprising a boron atom.

[0063] Furthermore, the light-emitting dopant is preferably a light-emitting dopant selected from polycyclic aromatic compounds represented by the following general formula (4a) or (4b).

[0064] [Chemistry 11]

[0065]

[0066] Here, Ring J, Ring K, Ring C, Ring D, Ring E, Ring F, Ring G, and Ring H are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 24 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic ring having 3 to 17 carbon atoms.

[0067] Y 1 are independently B, P, P=O, P=S, Al, Ga, As, Si-R 3 or Ge-R 3 , preferably B, P, P=O or P=S, more preferably B.

[0068] R 3 Each independently represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0069] X 2 O, N-Ar 4 , S or Se, preferably O, N-Ar 4 or S, more preferably O or N-Ar 4 .

[0070] Ar 4 Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to eight of these groups are linked.

[0071] N-Ar 4 It may bond with any of ring J, ring K, ring C, ring D, ring E, ring F, ring G, or ring H to form a heterocyclic ring containing N.

[0072] R 4Each independently represents a cyano group, a deuterium group, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, a diheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0073] g and h represent the number of substitutions and each independently represents an integer of 0 to 4; i and j represent the number of substitutions and each independently represents an integer of 0 to 3; and k represents the number of substitutions and each independently represents an integer of 0 to 2.

[0074] As a preferred form of the polycyclic aromatic compound represented by the general formula (4a), a boron-containing polycyclic aromatic compound represented by the following formula (5a) can be listed. As a preferred form of the polycyclic aromatic compound represented by the general formula (4b), a boron-containing polycyclic aromatic compound represented by the following formula (5b) can be listed.

[0075] [Chemistry 12]

[0076]

[0077] Here, X 3 Each independently represents N-Ar 4 , O, or S, but at least one X 3 N-Ar 4 .Ar 4 、R 4 , g, h, i, j, and k have the same meanings as in the case of the general formula (4a) or (4b).

[0078] In the polycyclic aromatic compounds represented by the general formula (4a), general formula (4b), general formula (5a), and general formula (5b), the difference (ΔEST) between the excited singlet energy (S1) and the excited triplet energy (T1) calculated by measuring the emission spectrum and the phosphorescence spectrum is preferably less than 0.20 eV, more preferably less than 0.18 eV, and even more preferably less than 0.10 eV.

[0079] The organic electroluminescent device of the present invention preferably includes one or more light-emitting layers between opposing anodes and cathodes, and the organic electroluminescent device includes a first host selected from the compound represented by the general formula (1), a second host, and a light-emitting dopant containing a boron atom. More preferably, the organic electroluminescent device includes a compound represented by the following general formula (6) as the second host. In addition, it is preferred that the compound represented by the general formula (1) is an electron-transporting host, and the second host is a hole-transporting host.

[0080] [Chemistry 13]

[0081]

[0082] Here, Z in the general formula (6) is a group containing an indolocarbazole ring represented by the general formula (7), and ** represents a group containing an indolocarbazole ring represented by L. 3 In addition, the ring A in the general formula (7) is a heterocyclic ring represented by the general formula (8), and the ring A is condensed with the adjacent ring at an arbitrary position.

[0083] L 3 and L 4 Each is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0084] Ar 5 and Ar 6 Each of the groups is independently deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to eight of these aromatic groups are linked.

[0085] R 5 are independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0086] v, w, q 1 ,q 2 ,q 3 , and r represent the number of substitutions, v represents an integer from 1 to 3, w represents an integer from 0 to 3, q 1 and q 3 Each independently represents an integer from 0 to 4, q 2 represents an integer from 0 to 2, and r represents an integer from 0 to 3.

[0087] Preferred embodiments of the general formula (6) include the following general formula (6a) and general formula (6b).

[0088] [Chemistry 14]

[0089]

[0090] Z, Ar 5 , v and w have the same meanings as in general formula (6), X 4 Indicates O, or S. R 6 Each of them is independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0091] Effects of the Invention

[0092] An organic EL device using the compound represented by the general formula (1) of the present invention can have high luminous efficiency and a long life. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] [ Figure 1 ] is a schematic cross-sectional view showing an example of an organic EL element. DETAILED DESCRIPTION

[0094] The present invention relates to a material for an organic electroluminescent element (organic EL element) using a compound represented by the general formula (1). In addition, the organic EL element of the present invention has one or more light-emitting layers between opposing anodes and cathodes, and at least one light-emitting layer contains a host selected from the compound represented by the general formula (1) and a light-emitting dopant containing a boron atom, preferably a first host, a second host, and a light-emitting dopant containing a boron atom selected from the compound represented by the general formula (1). More preferably, the material contains a second host selected from the compound represented by the general formula (6), and further contains a polycyclic aromatic compound represented by the general formula (4a) or the general formula (4b), more specifically, a polycyclic aromatic compound represented by the general formula (5a) or the general formula (5b) as a light-emitting dopant.

[0095] The present invention will first be described with respect to the compound for an organic electroluminescent device represented by the general formula (1). In the general formula (1), Ad is an adamantyl group represented by the general formula (2), preferably represented by the general formula (3).

[0096] X independently represents N, or CR 1 , at least one X represents N, preferably all X represent N.

[0097] R 1 independently represents hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups.

[0098] In R 1In the case of an aliphatic hydrocarbon group having 1 to 10 carbon atoms, the group may be any of linear, branched, or cyclic. Specific examples thereof include linear saturated hydrocarbon groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-dodecyl, n-tetradecyl, and n-octadecyl; branched saturated hydrocarbon groups such as isopropyl, isobutyl, tert-butyl, neopentyl, 2-ethylhexyl, and 2-hexyloctyl; and saturated alicyclic hydrocarbon groups such as cyclopentyl, cyclohexyl, cyclooctyl, 4-butylcyclohexyl, and 4-dodecylcyclohexyl. Methyl, ethyl, n-propyl, n-butyl, tert-butyl, neopentyl, or cyclohexyl are preferred.

[0099] As R 1 Specific examples of the unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms include benzene, naphthalene, acenaphthene, acenaphthylene, anthracene, A group produced by extracting one hydrogen from pyrene, phenanthrene, triphenylene, fluorene, or benz[a]anthracene. Preferred examples include those derived from benzene, naphthalene, anthracene, A group derived from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, a phenyl group or a naphthyl group can be mentioned.

[0100] As R 1 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms include nitrogen-containing aromatic compounds having a pyrrole ring such as pyrrole, pyrrolopyrrole, indole, isoindole, pyrroloisoindole, or carboline; and groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, carbazole, pyridine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, or quinoxaline. Preferred groups are those derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole, and more preferred are dibenzothienyl, dibenzofuranyl, or carbazolyl.

[0101] As R 1 Specific examples of the unsubstituted linked aromatic group include groups formed by removing one hydrogen atom from two to eight linked aromatic groups described in the specific examples of the unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms and the unsubstituted heteroaromatic group having 3 to 17 carbon atoms.

[0102] Ar 1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups, Ar 1Preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 11 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 11 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to eight of these aromatic groups are linked.

[0103] As Ar 1 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms. Preferred examples include groups produced by removing b+1 hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene. More preferred examples include phenyl groups.

[0104] As Ar 1 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, furan, benzofuran, or indole by removing b+1 hydrogen atoms. More preferred examples include groups derived from benzothiophene, benzofuran, or indole by removing b+1 hydrogen atoms.

[0105] As Ar 1 Specific example of an unsubstituted linked aromatic group, and R 1 The same applies to the case of an unsubstituted linked aromatic group.

[0106] R independently represents deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

[0107] Specific examples of when R is an aliphatic hydrocarbon group having 1 to 10 carbon atoms are as follows: 1 The same applies to the case of an aliphatic hydrocarbon group having 1 to 10 carbon atoms. Among them, preferred examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a tert-butyl group, a neopentyl group, and a cyclohexyl group.

[0108] As a specific example of when R is an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, 1 The same applies to unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms. Preferred examples include groups derived from aromatic hydrocarbons such as benzene and naphthalene by removing one hydrogen atom. More preferred examples include phenyl groups.

[0109] Specific examples of when R is an unsubstituted heteroaromatic group having 3 to 17 carbon atoms include the following: 1The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuranindole, or carbazole. More preferred are dibenzothiophenyl, dibenzofuranyl, or carbazolyl.

[0110] As a specific example when R is an unsubstituted linked aromatic group, 1 The same applies to the case of an unsubstituted linked aromatic group.

[0111] L 1 , and L 2 Each independently represents a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups, L 1 and L 2 Preferably, each independently represents a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, and more preferably represents a direct bond.

[0112] As L 1 , and L 2 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred are those selected from benzene, naphthalene, anthracene, An aromatic hydrocarbon group derived from the extraction of two hydrogen atoms from an aromatic hydrocarbon such as pyrene, phenanthrene, triphenylene, and fluorene. More preferably, a group derived from the extraction of two hydrogen atoms from benzene or naphthalene can be mentioned.

[0113] As L 1 , and L 2 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms include L 1 For other than divalent 1 The same as described above. Among them, preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole. More preferred examples include groups derived from dibenzothiophene, dibenzofuran, or carbazole.

[0114] As L 1 , and L 2 Specific examples of unsubstituted linked aromatic groups include L 1 , and L 2 For other than divalent radicals and R 1 The same applies to the case of an unsubstituted linked aromatic group.

[0115] a represents the number of substitutions and independently represents an integer from 0 to 4, more preferably aa=0. b to f represent the number of substitutions and independently represent an integer from 0 to 4, and satisfy the condition b+c+d+e+f≧1. Preferably, b+c+d≧1, more preferably b+c+d+e+f≧2.

[0116] The glass transition temperature (Tg) of the compound for the organic electroluminescent device of the present invention is preferably 135° C. or higher, more preferably 140° C. or higher. The compound of the present invention represented by the general formula (1) has a high glass transition temperature due to the adamantyl group, and thus has high resistance to heat generated when the device is driven, which is one of the reasons for the long life of the organic EL device of the present invention.

[0117] The compound of the present invention is excellent as a host material for use in a light-emitting layer of an organic EL device. The organic EL device of the present invention comprises one or more light-emitting layers between opposing anodes and cathodes. In the organic electroluminescent device, at least one light-emitting layer comprises a host selected from the compound represented by the general formula (1) and a light-emitting dopant. The light-emitting dopant is preferably a light-emitting dopant containing a boron atom.

[0118] In the organic EL device of the present invention, the luminescent dopant is preferably a compound represented by the general formula (4a) or (4b). The compound represented by the general formula (4a) or (4b) is described below.

[0119] In the general formula (4a) or (4b), Ring J, Ring K, Ring C, Ring D, Ring E, Ring F, Ring G, and Ring H are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 24 carbon atoms, or a substituted or unsubstituted aromatic heterocycle having 3 to 17 carbon atoms, preferably an aromatic hydrocarbon ring having 6 to 20 carbon atoms, or an aromatic heterocycle having 3 to 15 carbon atoms, and more preferably an aromatic hydrocarbon ring having 6 to 20 carbon atoms. As described above, Rings C to K represent aromatic hydrocarbon rings or aromatic heterocycles, and therefore, in this specification, these are collectively referred to as aromatic rings.

[0120] Specific examples of the aromatic ring include benzene, naphthalene, dihydroacenaphthene, acenaphthene, azulene, anthracene, The ring of pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthrapyridine, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyrone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole. More preferably, it is a benzene ring, naphthalene ring, anthracene ring, triphenylene ring, phenanthrene ring, pyrene ring, pyridine ring, dibenzofuran ring, dibenzothiophene ring, or carbazole ring.

[0121] Y 1 are independently B, P, P=O, P=S, Al, Ga, As, Si-R 3 or Ge-R 3 , preferably B, P, P=O or P=S, more preferably B.

[0122] R 3 Each of the groups is independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, preferably an aliphatic hydrocarbon group having 1 to 8 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms. More preferably, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0123] As R 3 Specific examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are as follows: 1 The same applies to the case of an aliphatic hydrocarbon group having 1 to 10 carbon atoms. Among them, preferred examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a tert-butyl group, a neopentyl group, and a cyclohexyl group.

[0124] As R 3 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred are benzene, naphthalene, anthracene, A group derived from pyrene, phenanthrene, triphenylene, or fluorene by removing one hydrogen atom. More preferably, it is phenyl or naphthyl.

[0125] As R 3 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1The same is true for an unsubstituted heteroaromatic group having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0126] X 2 O, N-Ar 4 , S or Se, preferably O, N-Ar 4 or S, more preferably O or N-Ar 4 .

[0127] N-Ar 4 It may bond with any of ring J, ring K, ring C, ring D, ring E, ring F, ring G, or ring H to form a heterocyclic ring containing N.

[0128] Ar 4 Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic rings. Preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to six linked aromatic rings of these. More preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to four linked aromatic rings of these. Even more preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0129] As Ar 4 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred examples include benzene, naphthalene, anthracene, A group generated by removing one hydrogen from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, phenyl or naphthyl can be mentioned.

[0130] As Ar 4 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1The same explanation as for the specific examples of an unsubstituted heteroaromatic group having 3 to 17 carbon atoms is given. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0131] As Ar 4 In the case of an unsubstituted linked aromatic group, R 1 The same applies to the case of an unsubstituted linked aromatic group.

[0132] R 4 Each independently represents a cyano group, a deuterium group, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. Preferred are diarylamino groups having 12 to 36 carbon atoms, arylheteroarylamino groups having 12 to 36 carbon atoms, diheteroarylamino groups having 12 to 36 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms. More preferred is a diarylamino group having 12 to 24 carbon atoms, an arylheteroarylamino group having 12 to 24 carbon atoms, a diheteroarylamino group having 12 to 24 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0133] As R 4 Specific examples of the diarylamino group having 12 to 44 carbon atoms, the arylheteroarylamino group having 12 to 44 carbon atoms, the diheteroarylamino group having 12 to 44 carbon atoms, and the aliphatic hydrocarbon group having 1 to 10 carbon atoms include diphenylamino, dibiphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenanthrylamino, dipyrenylamino, dibenzofuranylphenylamino, dibenzofuranylbiphenylamino, dibenzofuranylnaphthylamino, dibenzofuranylanthrylamino, dibenzofuranylphenanthrylamino, dibenzofuranylpyrenylamino, bisdibenzofuranylamino, carbazolylphenylamino, carbazolylnaphthylamino, carbazolylanthrylamino, carbazolylphenanthrylamino, carbazolylpyrenylamino, dicarbazolylamino, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and nonyl groups. Preferred are diphenylamino, diphenylamino, phenylbenzylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenanthrylamino, and dipyrenylamino, and more preferred are diphenylamino, diphenylamino, phenylbenzylamino, naphthylphenylamino, dinaphthylamino, dibenzofuranylphenylamino, and carbazolylphenylamino.

[0134] As R 4 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred examples include benzene, naphthalene, anthracene, A group generated by removing one hydrogen from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, phenyl or naphthyl can be mentioned.

[0135] As R 4 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0136] g and h represent the number of substitutions and each independently represents an integer from 0 to 4, preferably an integer from 0 to 2, and more preferably an integer from 0 to 1. i and j represent the number of substitutions and each independently represents an integer from 0 to 3, preferably an integer from 0 to 2, and more preferably an integer from 0 to 1. k represents the number of substitutions and each independently represents an integer from 0 to 2, and preferably 0 to 1.

[0137] As a preferred form of the polycyclic aromatic compound represented by the general formula (4a), a boron-containing polycyclic aromatic compound represented by the following formula (5a) can be listed. As a preferred form of the polycyclic aromatic compound represented by the general formula (4b), a boron-containing polycyclic aromatic compound represented by the following formula (5b) can be listed.

[0138] In the compounds represented by the general formula (5a) and the general formula (5b), X 3 Each independently represents N-Ar 4 , O, or S, but at least one X 3 N-Ar 4 In addition, the symbols common to the general formula (4a) or the general formula (4b) have the same meanings.

[0139] The organic EL device of the present invention includes one or more light-emitting layers between opposing anode and cathode. In the organic electroluminescent device, at least one light-emitting layer contains a first host selected from the compound represented by the general formula (1), a second host, and a light-emitting dopant containing a boron atom. The second host is preferably a compound represented by the general formula (6).

[0140] In the general formula (6), Z is a group containing an indole and carbazole ring represented by the general formula (7), and ** in the formula represents a group containing an indole and carbazole ring represented by the general formula (7). 3The bonding point. In addition, the ring A in the formula is a heterocyclic ring represented by the general formula (8), and the ring A is condensed with the adjacent ring at any position. The Z is preferably a group containing an indolocarbazole ring represented by the following general formula (101).

[0141] [Chemistry 15]

[0142]

[0143] The ** in formula (101) indicates that 3 The bond position.

[0144] L 3 and L 4 Each independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms. More preferably, it represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0145] As L 3 and L 4 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, benzene, naphthalene, anthracene, Pyrene, phenanthrene, triphenylene, or fluorene. More preferably, benzene or naphthalene can be mentioned. In addition, L 3 is a v+w valence basis, L 4 It is a group with a valence of r+1.

[0146] As L 3 and L 4 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted heteroaromatic group having 3 to 17 carbon atoms. Among them, preferably, thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole can be cited. 3 Where is the radical produced by removing v+w hydrogens, L 4 Here, r is a group formed by removing r + 1 hydrogen atoms. More preferably, dibenzothiophenyl, dibenzofuranyl, or carbazolyl can be mentioned.

[0147] Ar 5 and Ar 6Each of the groups is independently deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to eight of these aromatic groups are linked. Preferably, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to four of these are linked. More preferably, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to three of these are linked. Further preferably, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0148] As Ar 5 and Ar 6 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred examples include benzene, naphthalene, anthracene, A group generated by removing one hydrogen from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, phenyl or naphthyl can be mentioned.

[0149] As Ar 5 and Ar 6 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0150] As Ar 5 and Ar 6 In the case of an unsubstituted linked aromatic group, R 1 The same applies to the case of an unsubstituted linked aromatic group.

[0151] R 5The group is independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, preferably deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms. More preferably, the group is deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0152] As R 5 Specific examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are as follows: 1 The same applies to the case of an aliphatic hydrocarbon group having 1 to 10 carbon atoms. Among them, preferred examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a tert-butyl group, a neopentyl group, and a cyclohexyl group.

[0153] As R 5 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred examples include benzene, naphthalene, anthracene, A group generated by removing one hydrogen from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, phenyl or naphthyl can be mentioned.

[0154] As R 5 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0155] v represents the number of substitutions, and is an integer of 1 to 3, preferably 1 or 2. w represents the number of substitutions, and is an integer of 0 to 3, preferably 0 to 2. q 1 and q 3 represents the number of substitutions, and each independently represents an integer of 0 to 4, and is preferably an integer of 0 to 2. 2 represents the number of substitutions, represents an integer of 0 to 2, and is preferably 0 or 1. r represents the number of substitutions, represents an integer of 0 to 3, and is preferably 0 to 2.

[0156] The preferred embodiment of the general formula (6) is the general formula (6a) or the general formula (6b). In the general formula (6a) and the general formula (6b), X 4 represents O or S. In addition, the symbols common to those in the general formula (6) have the same meanings.

[0157] In the general formula (6b), R 6 Each of the above groups is independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, preferably deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 15 carbon atoms. More preferably, it is deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0158] As R 6 Specific examples of aliphatic hydrocarbon groups having 1 to 10 carbon atoms are as follows: 1 The same applies to the case of an aliphatic hydrocarbon group having 1 to 10 carbon atoms. Among them, preferred examples include methyl, ethyl, n-propyl, n-butyl, tert-butyl, neopentyl, and cyclohexyl.

[0159] As R 6 Specific examples of unsubstituted aromatic hydrocarbon groups having 6 to 18 carbon atoms are as follows: 1 The same applies to the case of an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms. Among them, preferred examples include benzene, naphthalene, anthracene, A group generated by removing one hydrogen from pyrene, phenanthrene, triphenylene, or fluorene. More preferably, phenyl or naphthyl can be mentioned.

[0160] As R 6 Specific examples of unsubstituted heteroaromatic groups having 3 to 17 carbon atoms are as follows: 1 The same applies to unsubstituted heteroaromatic groups having 3 to 17 carbon atoms. Preferred examples include groups derived from thiophene, benzothiophene, dibenzothiophene, furan, benzofuran, dibenzofuran, or carbazole by removing one hydrogen atom. More preferred examples include dibenzothiophenyl, dibenzofuranyl, and carbazolyl.

[0161] In this specification, a linked aromatic group refers to a group in which aromatic rings of an aromatic hydrocarbon group or an aromatic heterocyclic group are linked by a single bond. These may be linked in a straight chain or in a branched chain. In addition, the linked aromatic rings may be the same as or different from each other. When it corresponds to a linked aromatic group, it is different from an aromatic hydrocarbon group having a substituent or an aromatic heterocyclic group having a substituent.

[0162] In the general formula (1), the general formula (2), the general formula (3), the general formula (4a), the general formula (4b), the general formula (5a), the general formula (5b), the general formula (6), the general formula (6a), the general formula (6b), the general formula (7), the general formula (8), and the general formula (101), Ar1 ~Ar 5 、R 1 ~R 6 、L 1 ~L 4 In the case of an aromatic hydrocarbon group, an aromatic heterocyclic group, or a linked aromatic group, these may have a substituent. Preferred substituents include deuterium, a triarylsilyl group having 18 to 36 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and a diarylamino group having 12 to 44 carbon atoms. Here, when the substituent is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, it may be linear, branched, or cyclic. Furthermore, the number of substituents may be 0 to 5, preferably 0 to 2. When an aromatic hydrocarbon group or an aromatic heterocyclic group has a substituent, the carbon number of the substituent is not included in the calculation of the carbon number. However, it is preferred that the total carbon number, including the carbon number of the substituent, falls within the above range.

[0163] Specific examples of the substituent include deuterium, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, diphenylamino, naphthylphenylamino, dinaphthylamino, dianthrylamino, diphenanthrylamino, dipyrenylamino, and triphenylsilyl. Preferred examples include deuterium, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, diphenylamino, naphthylphenylamino, dinaphthylamino, and triphenylsilyl.

[0164] In this specification, in general formula (1), general formula (2), general formula (3), general formula (4a), general formula (4b), general formula (5a), general formula (5b), general formula (6), general formula (6a), general formula (6b), general formula (7), general formula (8), and general formula (101), part or all of the hydrogen may be deuterium.

[0165] Specific examples of the compound represented by the general formula (1) are shown below, but the compound is not limited to these exemplified compounds.

[0166] [Chemistry 16]

[0167]

[0168] [Chemistry 17]

[0169]

[0170] [Chemistry 18]

[0171]

[0172] [Chemistry 19]

[0173]

[0174] [Chemistry 20]

[0175]

[0176] Specific examples of compounds represented by the general formula (4a) or (4b), and preferred embodiments of the general formula (4a) or (4b), namely, the general formula (5a) or (5b), are shown below, but the compounds are not limited to these exemplified compounds.

[0177] [Chemistry 21]

[0178]

[0179] [Chemistry 22]

[0180]

[0181] [Chemistry 23]

[0182]

[0183] [Chemistry 24]

[0184]

[0185] [Chemistry 25]

[0186]

[0187] [Chemistry 26]

[0188]

[0189] [Chemistry 27]

[0190]

[0191] [Chemistry 28]

[0192]

[0193] [Chemistry 29]

[0194]

[0195] [Chemistry 30]

[0196]

[0197] [Chemistry 31]

[0198]

[0199] [Chemistry 32]

[0200]

[0201] [Chemistry 33]

[0202]

[0203] [Chemistry 34]

[0204]

[0205] [Chemistry 35]

[0206]

[0207] [Chemistry 36]

[0208]

[0209] [Chemistry 37]

[0210]

[0211] [Chemistry 38]

[0212]

[0213] [Chemistry 39]

[0214]

[0215] [Chemistry 40]

[0216]

[0217] [Chemistry 41]

[0218]

[0219] Specific examples of the compounds represented by the general formula (6) and its preferred embodiment, namely, the general formula (6a) or the general formula (6b) are shown below, but the compounds are not limited to these exemplified compounds.

[0220] [Chemistry 42]

[0221]

[0222] [Chemistry 43]

[0223]

[0224] [Chemistry 44]

[0225]

[0226] [Chemistry 45]

[0227]

[0228] [Chemistry 46]

[0229]

[0230] [Chemistry 47]

[0231]

[0232] [Chemistry 48]

[0233]

[0234] [Chemistry 49]

[0235]

[0236] [Chemistry 50]

[0237]

[0238] [Chemistry 51]

[0239]

[0240] [Chemistry 52]

[0241]

[0242] [Chemistry 53]

[0243]

[0244] [Chemistry 54]

[0245]

[0246] [Chemistry 55]

[0247]

[0248] [Chemistry 56]

[0249]

[0250] [Chemistry 57]

[0251]

[0252] [Chemistry 58]

[0253]

[0254] [Chemistry 59]

[0255]

[0256] [Chemistry 60]

[0257]

[0258] [Chemistry 61]

[0259]

[0260] [Chemistry 62]

[0261]

[0262] [Chemistry 63]

[0263]

[0264] [Chemistry 64]

[0265]

[0266] [Chemistry 65-1]

[0267]

[0268] The polycyclic aromatic compounds represented by the general formula (4a), general formula (4b), general formula (5a), and general formula (5b) used as luminescent dopants in the organic EL device of the present invention preferably have a ΔEST, which is the difference between the excited singlet energy (S1) and the excited triplet energy (T1), of 0.20 eV or less. It is more preferably 0.15 eV or less, and even more preferably 0.10 eV or less. In this case, ΔEST(S1-T1) is a value calculated by measuring the emission spectrum of S1 and the phosphorescence spectrum of T1.

[0269] S1 and T1 can also be calculated using theoretical calculations using the molecular activation program Gaussian 16. The values ​​of the singlet excited state energy [S1(theo)] and triplet excited state energy [T1(theo)] obtained through theoretical calculations are used to calculate ΔEST(theo) [S1 - T1(theo)]. In this case, ΔEST(theo) is preferably 0.60 eV or less, more preferably 0.50 eV or less. A low ΔEST(theo) obtained through theoretical calculations facilitates backexchange crossing, allowing triplet excitons to be efficiently utilized for luminescence, thus contributing to the expectation of high luminescence efficiency.

[0270] Next, the structure of the organic EL element of the present invention will be described with reference to the drawings, but the structure of the organic EL element of the present invention is not limited thereto.

[0271] Figure 11 is a cross-sectional view showing a structural example of a general organic EL element used in the present invention, wherein 1 represents a substrate, 2 represents an anode, 3 represents a hole injection layer, 4 represents a hole transport layer, 5 represents a light-emitting layer, 6 represents an electron transport layer, and 7 represents a cathode. The organic EL element of the present invention may have an exciton blocking layer adjacent to the light-emitting layer, and may also have an electron blocking layer between the light-emitting layer and the hole injection layer. The exciton blocking layer may be inserted into either the anode side or the cathode side of the light-emitting layer, and may also be inserted into both sides at the same time. In the organic EL element of the present invention, an anode, a light-emitting layer, and a cathode are required layers, but in addition to the required layers, a hole injection transport layer and an electron injection transport layer may also be included, and a hole blocking layer may also be included between the light-emitting layer and the electron injection transport layer. In addition, a hole injection transport layer refers to either or both of a hole injection layer and a hole transport layer, and an electron injection transport layer refers to either or both of an electron injection layer and an electron transport layer.

[0272] It can also be used for Figure 1 In the opposite structure, the cathode 7, electron transport layer 6, light emitting layer 5, hole transport layer 4, hole injection layer 3, and anode 2 are sequentially stacked on the substrate 1. In this case, layers can be added or omitted as needed.

[0273] -Substrate- The organic EL element of the present invention is preferably supported on a substrate. The substrate is not particularly limited as long as it is a substrate conventionally used for organic EL elements. For example, substrates made of glass, transparent plastic, quartz, etc. can be used.

[0274] -Anode- As the anode material in the organic EL element, a material containing a metal, alloy, electrically conductive compound, or a mixture thereof with a large work function (4 eV or more) can be preferably used. Specific examples of such electrode materials include: metals such as Au; conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. In addition, amorphous materials such as IDIXO (In2O3-ZnO) that can be made into transparent conductive films can also be used. The anode can be formed into a thin film of these electrode materials by methods such as evaporation or sputtering, and a pattern of the desired shape can be formed by photolithography. Alternatively, when pattern accuracy is not very important (approximately 100 μm or more), a mask of the desired shape can be used to form a pattern during evaporation or sputtering of the electrode material. Alternatively, when using a coatable substance such as an organic conductive compound, a wet film forming method such as printing or coating can be used. When light is extracted from the anode, the transmittance is preferably greater than 10%, and the sheet resistance of the anode is preferably less than several hundred Ω / □. The film thickness also depends on the material, but is generally selected within the range of 10nm to 1000nm, preferably 10nm to 200nm.

[0275] -Cathode- On the other hand, cathode materials can be made from metals with low work functions (less than 4 eV) (called electron-injecting metals), alloys, electrically conductive compounds, or mixtures thereof. Specific examples of such electrode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium / copper mixtures, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, indium, lithium / aluminum mixtures, and rare earth metals. Among these, mixtures of an electron-injecting metal with a second metal that is a stable metal with a larger work function value are suitable in terms of electron injectability and durability against oxidation, such as magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al2O3) mixtures, lithium / aluminum mixtures, and aluminum. The cathode can be fabricated by forming a thin film of these cathode materials using methods such as evaporation or sputtering. Furthermore, the sheet resistance of the cathode is preferably less than several hundred Ω / □, and the film thickness is typically selected within the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. Furthermore, in order to transmit the emitted light, it is preferable that either the anode or cathode of the organic EL element is transparent or semi-transparent, since the emission brightness is improved.

[0276] In addition, after forming the metal with a film thickness of 1nm to 20nm on the cathode, the conductive transparent material listed in the description of the anode is formed thereon, thereby making a transparent or translucent cathode. By applying the method, an element in which both the anode and the cathode are transparent can be made.

[0277] -Light-emitting layer- The light-emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from the anode and the cathode, respectively. The light-emitting layer contains a light-emitting dopant and a host.

[0278] The mixing ratio of the luminescent dopant to the host is preferably 0.10% to 10% luminescent dopant and 99.9% to 90% host, more preferably 1.0% to 5.0% luminescent dopant and 99% to 95% host, and even more preferably 1.0% to 3.0% luminescent dopant and 99% to 97% host. In this specification, unless otherwise specified, % refers to mass %.

[0279] As the host in the light-emitting layer, the compound represented by the general formula (1) of the present invention can be used.

[0280] It is preferred that when the compound represented by the general formula (1) of the present invention is included as the first host material, the compound represented by the general formula (6) is used as the second host. In addition, it is preferred that the compound represented by the general formula (1) is an electron-transporting host, and the compound represented by the general formula (6) is a hole-transporting host. Here, as a mixing ratio of the first host and the second host, it is preferred to use the first host as 10% to 90% and the second host as 90% to 10%. It is more preferred that the first host is 30% to 70% and the second host is 70% to 30%, and it is further preferred that the first host is 30% to 50% and the second host is 70% to 50%.

[0281] In the light-emitting layer, the host represented by the general formula (1) or (6) of the present invention may be used alone or in combination of two or more different compounds. Furthermore, one or more known hosts may be used in combination, but their amount may be set to 50% or less, preferably 25% or less, of the total amount of the host materials.

[0282] Other known hosts that can be used are preferably compounds that have both hole-transporting and electron-transporting capabilities and a high glass transition temperature, and preferably have a T1 greater than that of the luminescent dopant. Specifically, the host's T1 is preferably higher than the T1 of the luminescent dopant by at least 0.010 eV, more preferably by at least 0.030 eV, and even more preferably by at least 0.10 eV. TADF-active compounds can also be used as host materials, preferably with a ΔEST of 0.20 eV or less.

[0283] As the other known subjects, they are known from a large number of patent documents, etc., and can be selected from these. As specific examples of the subject, there is no particular limitation, and examples include: indole derivatives, carbazole derivatives, indolocarbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, phenylenediamine derivatives, arylamine derivatives, styrylanthracene derivatives, fluorenone derivatives, distilbenes derivatives, triphenylene derivatives, carborane derivatives, porphyrin derivatives, phthalocyanine derivatives, various metal complexes represented by metal complexes of 8-hydroxyquinoline derivatives or metal phthalocyanines, benzoxazole or benzothiazole derivatives, poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, polythiophene derivatives, polyphenylene derivatives, polystyrene vinylene derivatives, polyfluorene derivatives and other polymer compounds.

[0284] When using a plurality of types of subjects, each subject may be deposited from a different deposition source, or the subjects may be pre-mixed before deposition to form a premix, thereby allowing the plurality of subjects to be deposited simultaneously from a single deposition source.

[0285] As a method for premixing, a method that can mix as uniformly as possible is desirable, and examples thereof include pulverization mixing, or a method of heating and melting under reduced pressure or in an inert gas environment such as nitrogen, or sublimation, but are not limited to these methods. In addition, the premix can be in the form of a powder, a rod, or granules.

[0286] When the compound represented by the general formula (1) of the present invention is used as a host, the energy level of the highest occupied molecular orbital (HOMO) obtained by structure optimization calculation based on density functional calculation B3LYP / 6-31G(D) is preferably less than -4.7 eV, more preferably in the range of -5.9 eV to -4.7 eV.

[0287] The energy level of the lowest unoccupied molecular orbital (LUMO) obtained by the structural optimization calculation is preferably not less than -2.5 eV, and more preferably in the range of -1.8 eV to -1.2 eV.

[0288] When the compound represented by the general formula (1) of the present invention is used as a host, the difference (absolute value) between the HOMO level and the LUMO level is preferably within the range of 2.5 eV to 5.0 eV, more preferably within the range of 3.0 eV to 4.5 eV.

[0289] As the light-emitting dopant in the light-emitting layer, it is preferable to use a polycyclic aromatic compound material represented by the general formula (4a), the general formula (4b), the general formula (5a), or the general formula (5b).

[0290] The light-emitting layer may contain two or more light-emitting dopants. For example, two or more compounds represented by the general formula (1) or polycyclic aromatic compound materials represented by the general formula (4a), the general formula (4b), the general formula (5a), or the general formula (5b) may be used in combination, or two or more light-emitting dopants may be used in combination with light-emitting dopants containing other compounds. When the light-emitting layer contains the compound represented by the general formula (1) and the polycyclic aromatic compound materials represented by the general formula (4a), the general formula (4b), the general formula (5a), or the general formula (5b), it is preferred that the compound represented by the general formula (1) be used as the host material and the polycyclic aromatic compound materials represented by the general formula (4a), the general formula (4b), the general formula (5a), or the general formula (5b) be used as the light-emitting dopant.

[0291] The polycyclic aromatic compounds represented by the general formula (4a) or (4b), and the general formula (5a) or (5b) can emit blue light efficiently by utilizing the TADF mechanism. However, due to their low tolerance to holes and electrons, it is difficult to ensure a device lifespan sufficient for practical use in organic EL devices when used in combination with conventional host materials. On the other hand, the compound represented by the general formula (1) of the present invention has a higher tolerance to holes and electrons than conventional host compounds. Therefore, when the polycyclic aromatic compounds are used as dopants, the compound of the general formula (1) of the present invention is used as a host, thereby achieving an organic EL device with a longer lifespan.

[0292] When the light-emitting layer contains two or more luminescent dopants, the first dopant may be a compound represented by the general formula (4a), general formula (4b), general formula (5a), or general formula (5b), or a fluorescent dopant, and the second dopant may be a known compound used in combination as another luminescent dopant. The content of the first dopant relative to the host material is preferably 0.050% to 50%, and the content of the second dopant relative to the host material is preferably 0.050% to 50%, and the total content of the first dopant and the second dopant relative to the host material does not exceed 50%.

[0293] As other luminescent dopants, a large number of patent documents and the like are known, and thus they can be selected from these. Specific examples of dopants include, but are not particularly limited to, phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and Condensed ring derivatives, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives or bisstyrylbenzene derivatives such as bisstyrylarylene derivatives, bisstyrylarylene derivatives, diazabenzoindane derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives, dibenzofuran derivatives, coumarin derivatives, dicyanomethylene derivatives Pyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, quinolone derivatives, acridine derivatives, oxazine derivatives, phenyl ether derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, fluoropyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, purple ring derivatives, pyrrolopyrrole derivatives, squarylium derivatives, anthrone violet derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives and benzofluorene derivatives, etc.

[0294] As the other luminescent dopants, phosphorescent dopants can also be used. As phosphorescent dopants, an organometallic complex comprising at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold can be contained. More preferably, the organometallic complex comprising platinum can be suitably used, specifically the iridium complex described in "Journal of the American Chemical Society (J.Am.Chem.Soc.)" 2001,123,4304 or Japanese Patent Publication No. 2013-530515 or the platinum complex described in "Advanced Materials (Adv.Mater.)" 2014,26,7116 or Japanese Patent Publication No. 2018-2722, but is not limited to these.

[0295] The phosphorescent dopant material is not particularly limited, but specific examples include the following.

[0296] [Chemistry 65-2]

[0297]

[0298] [Chemistry 65-3]

[0299]

[0300] The luminescent dopant and the first host or the second host may be deposited from different deposition sources, or pre-mixed before deposition to form a pre-mixture, thereby simultaneously depositing the luminescent dopant and the first host or the second host from a single deposition source.

[0301] -Injection layer-

[0302] An injection layer is a layer placed between an electrode and an organic layer to reduce driving voltage or increase luminance. There are two types: hole injection layer and electron injection layer. These layers can be located between the anode and the light-emitting layer or hole transport layer, and between the cathode and the light-emitting layer or electron transport layer. Injection layers can be added as needed.

[0303] -Hole blocking layer-

[0304] The so-called hole blocking layer, in a broad sense, has the function of an electron transport layer and includes a hole blocking material that has the function of transporting electrons but has a significantly lower ability to transport holes. It can increase the probability of recombination between electrons and holes in the light-emitting layer by transporting electrons and blocking holes. In the hole blocking layer, known hole blocking materials can be used. In order to give full play to the characteristics of the luminescent dopant, the material used as the first host can also be used as the material of the hole blocking layer. In addition, multiple hole blocking materials can also be used in combination.

[0305] -Electron blocking layer-

[0306] The so-called electron blocking layer, in a broad sense, functions as a hole transport layer, increasing the probability of electron-hole recombination in the light-emitting layer by transporting holes and blocking electrons. As the material for the electron blocking layer, known electron blocking layer materials can be used. To maximize the properties of the luminescent dopant, the material used as the second host can also be used as the electron blocking layer material. The film thickness of the electron blocking layer is preferably 3 nm to 100 nm, more preferably 5 nm to 30 nm.

[0307] -Exciton blocking layer-

[0308] An exciton-blocking layer is a layer used to block excitons, generated by the recombination of holes and electrons within the light-emitting layer, from diffusing to the charge transport layer. By inserting this layer, excitons can be efficiently confined within the light-emitting layer, improving the device's luminous efficiency. In devices with two or more adjacent light-emitting layers, the exciton-blocking layer can be inserted between two adjacent light-emitting layers.

[0309] As the material of the exciton-blocking layer, a known exciton-blocking layer material can be used.

[0310] Examples of layers adjacent to the light-emitting layer include a hole-blocking layer, an electron-blocking layer, and an exciton-blocking layer. If these layers are not provided, the hole-transporting layer, the electron-transporting layer, and the like serve as adjacent layers.

[0311] -Hole transport layer-

[0312] The hole transport layer includes a hole transport material having the function of transporting holes, and the hole transport layer may be provided as a single layer or multiple layers.

[0313] As a hole transport material, it is a material having the injection or transport of holes, or the barrier property of electrons, and can be any of organic and inorganic substances. In the hole transport layer, any one can be selected from previously known compounds and used. As the hole transport material, for example, porphyrin derivatives, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, distyrene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers, etc., preferably using porphyrin derivatives, arylamine derivatives and styrylamine derivatives, more preferably using arylamine derivatives.

[0314] -Electron transport layer-

[0315] The electron transport layer includes a material having the function of transporting electrons, and the electron transport layer may be provided as a single layer or multiple layers.

[0316] As an electron transport material (sometimes also serving as a hole blocking material), it is sufficient as long as it has the function of transmitting the electrons injected from the cathode to the light-emitting layer. The electron transport layer can be selected from any of the compounds known in the past and used, for example, polycyclic aromatic derivatives such as naphthalene, anthracene, and phenanthroline, tris (8-hydroxyquinoline) aluminum (III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylmethane derivatives, anthracite dimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole derivatives, benzothiazole derivatives, indole and carbazole derivatives, etc. Furthermore, it is also possible to use polymer materials that introduce these materials into polymer chains or use these materials as the main chain of polymers.

[0317] The film-forming method of each layer when producing the organic EL device of the present invention is not particularly limited, and the device can be produced by either a dry process or a wet process.

[0318] Example

[0319] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these Examples, and can be implemented in various forms without departing from the spirit and scope of the present invention.

[0320] Synthesis example 1

[0321] [Chemistry 66]

[0322]

[0323] Synthesis of 3-Adamantanylcarbazole (1)

[0324] Carbazole (6.02 g, 36.3 mmol) and AlCl₃ (3.12 g, 23.7 mmol) were added to a 500 mL Schlenk tube purged with nitrogen, and dry dichloromethane (250 mL) was added under ice-cooling. After stirring, 1-chloroadamantan (7.44 g, 43.6 mmol) was added, and the mixture was stirred at room temperature for 18 hours. After quenching with ice water, the mixture was extracted with dichloromethane, and the organic layer was dried over Na₂SO₄ and concentrated. The residue was washed with hexane, and the filtrate was concentrated. The crude product was purified by silica gel column chromatography (developing solvent: hexane / ethyl acetate = 7:1, v / v) and further purified by GPC to obtain the target compound 1 [3-adamantylcarbazole (1)]. Yield: 19% (2.07 g)

[0325] 1 H NMR (400MHz, CDCl3): δ8.09-8.05(m,2H),7.95(s,1H),7.48(dd,J=8.4,1.4Hz,1 H),7.42-7.37(m,3H),7.23-7.20(m,1H),2.15(s,3H),2.05(s,6H),1.82(s,6H).

[0326] MS (MALDI-TOF): m / z calculated (calcd) 301.18 [M] + ; Found: 301.28.

[0327] [Chemistry 67]

[0328]

[0329] Synthesis of compound 1-1

[0330] To a nitrogen-purged 300 mL Schlenk tube, compound 1 [3-adamantylcarbazole (2.53 g, 8.38 mmol)] synthesized as described above, 2,4-dichloro-6-phenyl-1,3.5-triazine (663 mg, 2.93 mmol), palladium acetate (69 mg, 0.30 mmol), tri-tert-butylphosphonium tetrafluoroborate (329 mg, 1.13 mmol), t-BuONa (816 mg, 8.49 mmol), and dry toluene (100 mL) were added and stirred at 100°C for 18 hours. After cooling to room temperature, the mixture was separated with ethyl acetate, and the organic layer was dried over Na2SO4 and concentrated. The crude product was purified by silica gel column chromatography (developing solvent: hexane / dichloromethane = 4:1, v / v) to obtain the target compound 1-1. Yield: 57% (1.27 g).

[0331] 1 H NMR (400MHz, CDCl3): δ9.04(d,J=8.3Hz,2H),8.97(d,J=8.8Hz,2H),8.75(d,J=7.5Hz,2H),8.11(d,J=7.5Hz,2H),8.07(s, 2H),7.67(m,3H),7.60(d,J=8.8Hz,2H),7.53-7.49(m,2H),7.43(t,J=7.4Hz,2H),2.19(s,6H),2.10(s,12H),1.85(s,12H)

[0332] MS (MALDI-TOF): m / z calculated (calcd) 755.40 [M] + ; Found: 756.68.

[0333] Synthesis example 2

[0334] [Chemistry 68]

[0335]

[0336] Synthesis of Synthesis Example 1-2

[0337] To a 200 mL Schlenk tube purged with nitrogen was added Compound 1 [3-adamantyl-carbazole (1.37 g, 4.53 mmol)] synthesized as described above, 9-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)carbazole (1.12 g, 3.14 mmol), palladium acetate (107 mg, 0.48 mmol), tri-tert-butylphosphonium tetrafluoroborate (377 mg, 1.3 mmol), t-BuONa (607 mg, 6.3 mmol), and anhydrous toluene (90 mL), and the mixture was stirred at 90°C for 17 hours. After cooling to room temperature, the mixture was separated with ethyl acetate, and the organic layer was dried over Na2SO4 and concentrated. The crude product was purified by silica gel column chromatography (developing solvent: hexane / dichloromethane = 4:1, v / v) to obtain the target compound 1-2. Yield: 62% (1.21 g)

[0338] 1 H NMR (400MHz, CDCl3): δ9.07-9.03(m,3H),8.98(d,J=8.8Hz,1H),8.75(dd,J=7.7,1.9Hz,2H),8.11(d,J=7.5Hz,3H),8.07 (d,J=1.5Hz,1H),7.68(d,J=6.8Hz,3H),7.60-7.49(m,4H),7.44(q,J=7.0Hz,3H),2.18(s,3H),2.10(s,6H),1.85(s,6H)

[0339] MS (MALDI-TOF): m / z calculated (calcd) 621.29 [M] + ; Found: 621.45.

[0340] The compounds used in Examples and Comparative Examples are shown below.

[0341] [Chemistry 69]

[0342]

[0343] [Chemistry 70]

[0344]

[0345] [Chemistry 71]

[0346]

[0347] Calculation Example

[0348] Calculation of HOMO and LUMO values

[0349] HOMO and LUMO were calculated for the compound 1-1, compound 1-2, compound 1-3, compound 1-4, compound 1-5, compound 1-6, compound 1-7, and compound 1-8. In addition, for the calculation, a calculation based on density functional theory (DFT: Density Functional Theory) was used. As a calculation program, Gaussian was used, and the calculation was performed by structural optimization calculation based on density functional theory B3LYP / 6-31G (d). The results are shown in Table 1 below. It can be said that any of the materials of the present invention represented by general formula (1) has HOMO and LUMO values ​​that are preferred as a host material.

[0350] [Table 1]

[0351] Compound HOMO(eV) LUMO(eV) 1-1 -5.6 -1.7 1-2 -5.7 -1.8 1-3 -5.8 -1.8 1-4 -5.8 -1.4 1-5 -5.7 -1.7 1-6 -5.3 -1.8 1-7 -5.2 -1.9 1-8 -5.8 -1.8 H2 -5.6 -1.7 H3 -5.7 -1.8 H4 -5.8 -1.8 H5 -5.5 -1.9 H6 -5.2 -1.9 H7 -5.2 -2.0 H8 -5.6 -1.9 H9 -5.3 -1.9 H10 -6.0 -1.8

[0352] Determination of Tg value

[0353] The glass transition temperature (Tg) of Compound 1-1 and Compound 1-2 was measured. A DSC7020 manufactured by Hitachi High-Tech was used for the measurement. The results are shown in Table 2 below. It can be said that any of the compounds represented by Formula (1) of the present invention have a preferred Tg value.

[0354] [Table 2]

[0355] Compound Tg(℃) 1-1 200℃ 1-2 145℃ H3 111℃ H4 95℃

[0356] The S1 and T1 of compound 2-2 and compound 4-2 were measured using the following method.

[0357] The powder of compound 2-2 or compound 4-2 was dissolved in toluene solvent to a concentration of 10 -5 The solution was adjusted in the manner of M.

[0358] Regarding S1, the emission spectrum of the solution is measured, a tangent line is drawn for the rise on the short-wavelength side of the emission spectrum, and the wavelength value λedge [nm] of the intersection of the tangent line and the horizontal axis is substituted into the following formula (i) to calculate S1.

[0359] S1[eV]=1239.85 / λedge(i)

[0360] T1 is calculated by measuring the phosphorescence spectrum of the solution, drawing a tangent to the short-wavelength rise of the phosphorescence spectrum, and substituting the wavelength λedge [nm] of the intersection of the tangent and the horizontal axis into formula (ii).

[0361] T1[eV]=1239.85 / λedge(ii)

[0362] Table 3 shows the measurement results of S1 and T1, and the value of ΔEST, which is the difference between S1 and T1.

[0363] [Table 3]

[0364] Compound S1(eV) T1(eV) ΔEST (eV) 2-2 2.79 2.61 0.18 4-2 2.71 2.67 0.04

[0365] Compound 2-2 and Compound 4-2 exhibit ΔEST of 0.2 eV or less, which is generally considered suitable as thermally activated delayed fluorescence materials. Therefore, reverse intersystem crossing occurs easily, and triplet excitons can be efficiently used for light emission, so high light emission efficiency can be expected.

[0366] S1 and T1 can be determined by actual measurement as described above, or by theoretical calculation using a molecular orbital method program such as the one described below. While the absolute value of ΔEST(theo) obtained by the calculation method below may differ from the measured ΔEST, generally speaking, a smaller value indicates a higher likelihood of backexchange crossing, allowing efficient utilization of triplet excitons for luminescence, leading to the expectation of higher luminous efficiency. Furthermore, thermally activated delayed fluorescent materials with smaller ΔEST(theo) generally also have smaller measured ΔEST.

[0367] For 2-2, 4-2, 2-86, and 2-87, the light-emitting materials represented by general formula (4a) or general formula (4b), structural optimization calculations were performed using density functional theory (DFT) at the TDA-PBE0 / 6-31G* level using the molecular orbital program Gaussian 16. S1(theo), T1(theo), and ΔEST(theo) were calculated. The results are shown in Table 4.

[0368] [Table 4]

[0369]

[0370] As shown in Table 4, Example Compound 2-2, which exhibited a ΔEST of 0.2 eV or less, which is generally considered suitable in the measured value, exhibited a theoretically calculated ΔEST(theo)[eV] of 0.60 eV or less.

[0371] As shown in Table 4, 4-13, 2-86, and 2-87, which are luminescent materials represented by general formula (4a) or general formula (4b), show ΔEST(theo) as small as the measured ΔEST of 2-2 and 4-2, so reverse intersystem crossing is easily generated, and triplet excitons can be efficiently used for luminescence, so high luminescence efficiency can be expected.

[0372] Example 1

[0373] On a glass substrate on which an anode made of ITO with a thickness of 70 nm was formed, a vacuum deposition method was used at a vacuum degree of 4.0×10 -5 Pa is used to stack each thin film. First, HAT-CN is formed to a thickness of 10 nm on ITO as a hole injection layer, and then HT-1 is formed to a thickness of 25 nm as a hole transport layer. Next, compound EB-1 is formed to a thickness of 5 nm as an electron blocking layer. Next, compound 1-1 as the first host, compound 5-148 as the second host, and compound 4-2 as a luminescent dopant are co-deposited from different evaporation sources to form a light-emitting layer with a thickness of 30 nm. At this time, co-evaporation is performed under evaporation conditions in which the concentration of compound 4-2 becomes 2% and the mixing ratio of the first host to the second host becomes 30:70. Next, compound H1 is formed to a thickness of 5 nm as a hole blocking layer. Next, ET-1 is formed to a thickness of 40 nm as an electron transport layer. Lithium fluoride (LiF) is formed to a thickness of 1 nm as an electron injection layer on the electron transport layer. Finally, aluminum (Al) is formed to a thickness of 70 nm as a cathode on the electron injection layer to produce an organic EL element.

[0374] Examples 2 to 5, Comparative Example 1

[0375] An organic EL device was prepared in the same manner as in Example 1, except that the luminescent dopant, the first host, the second host, and the mixing ratio of the first host to the second host were the compounds or mixing ratios shown in Table 3. Furthermore, the mixing ratio was first host:second host.

[0376] [Table 5]

[0377] Luminescent dopants First subject Second subject Mixing ratio Example 1 4-2 1-1 5-148 50：50 Example 2 4-2 1-2 5-148 50：50 Example 3 4-2 1-2 5-148 40：60 Example 4 4-2 1-2 5-148 30：70 Example 5 4-2 1-2 5-148 20：80 Comparative Example 1 4-2 H2 5-148 50：50

[0378] The maximum emission wavelength, external quantum efficiency, and device life of the emission spectra of the organic EL devices prepared in Examples and Comparative Examples are shown in Table 6. The maximum emission wavelength and external quantum efficiency are obtained at a current density of 2.5 mA / cm 2 The value at the time of the test is the initial characteristic. Regarding the device life, the current density is 2.5mA / cm 2 The time it takes for the brightness to decay to 70% of the initial brightness.

[0379] [Table 6]

[0380]

[0381] The maximum emission wavelengths in Table 6 indicate that the organic EL elements of Examples 1 to 5 and Comparative Example 1 emit blue light. Furthermore, the results in Table 6 indicate that the external quantum efficiency and device lifetime of Examples 1 to 5 are improved compared to the Comparative Examples, demonstrating that the blue-emitting organic EL elements exhibit high efficiency and long lifetimes. This indicates that the compounds represented by general formula (1) of the present application exhibit superior properties compared to the known compounds of the Comparative Examples.

[0382] The compounds used in Example 6 and Comparative Example 2 are shown below.

[0383] [Chemistry 72]

[0384]

[0385] Example 6

[0386] On a glass substrate on which an anode made of ITO with a thickness of 70 nm was formed, a vacuum deposition method was used at a vacuum degree of 4.0×10 -5 Pa is used to stack the thin films shown below. First, the HAT-CN shown previously is formed into a thickness of 10 nm on ITO as a hole injection layer, and then HT-1 is formed into a thickness of 60 nm as a hole transport layer. Next, HT-2 is formed into a thickness of 5 nm as an electron blocking layer. Next, the compound (1-4-p) as the first host, the compound HT-2 as the second host, the phosphorescent dopant as the second dopant, i.e., the compound BD-2, and the compound 2-87 as the first dopant are co-evaporated from different evaporation sources to form a light-emitting layer with a thickness of 40 nm. At this time, co-evaporation is performed under evaporation conditions in which the concentration of BD-2 becomes 13% by mass, the concentration of 2-87 becomes 0.4% by mass, and the mass ratio of the first host to the second host becomes 40:60. Next, ET-2 is formed into a thickness of 5 nm as a hole blocking layer. Next, ET-2 is formed into a thickness of 31 nm as an electron transport layer. Furthermore, lithium fluoride (LiF) was formed to a thickness of 1 nm as an electron injection layer on the electron transport layer, and finally aluminum (Al) was formed to a thickness of 70 nm as a cathode on the electron injection layer to produce the organic EL device of Example 6.

[0387] Comparative Example 2

[0388] An organic EL device was produced in the same manner as in Example 6 except that the compounds shown in Table 7 were used as the first host and the second host.

[0389] [Table 7]

[0390]

[0391] The evaluation results of the prepared organic EL elements are shown in Table 2. When the organic EL elements obtained in Examples and Comparative Examples were connected to an external power supply and a DC voltage was applied, a light emission spectrum with a maximum emission wavelength of 450 nm to 480 nm was observed in all the organic EL elements, indicating that light emission was derived from Compound 2-87.

[0392] The voltage and power efficiency in the table are based on a drive current of 4.0 mA / cm 2 The value is the initial characteristic. In addition, the life is when the driving current is 4.0mA / cm 2 The lifetime characteristics are expressed as the time it takes for the brightness to decay to 95% when the initial brightness is set to 100%. In addition, the luminous color is confirmed using the emission spectrum of the organic EL element.

[0393] The results of Examples and Comparative Examples shown in Table 8 show that the organic EL device using the mixed material for an organic electroluminescent device of the present invention as a main component in the light-emitting layer emits blue light and has a long life.

[0394] [Table 8]

[0395]

[0396] Explanation of Figure Numbers

[0397] 1: Substrate

[0398] 2: Anode

[0399] 3: Hole injection layer

[0400] 4: Hole transport layer

[0401] 5: Luminous layer

[0402] 6: Electron transport layer

[0403] 7: cathode

Claims

1. A compound for an organic electroluminescent device, represented by the following general formula (1): [Chemistry 1] Here, Ad is an adamantyl group represented by the following general formula (2); [Chemistry 2] X independently represents N, or CR 1 , at least one X represents N; R 1 independently represents hydrogen, deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups; Ar 1 represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups; R independently represents deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms; L 1 , and L 2 Each independently represents a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups; a represents the number of substitutions, and independently represents an integer from 0 to 4; b to f represent the number of substitutions, and independently represent an integer from 0 to 4; wherein, Satisfies b+c+d+e+f≧1. 2 . The compound for an organic electroluminescent device according to claim 1 , wherein all X's are represented by N. 3 . The compound for an organic electroluminescent device according to claim 1 , wherein b+c+d≧1 is satisfied. The compound for an organic electroluminescent device according to claim 1 , wherein b+c+d+e+f≧2 is satisfied.

5. The compound for an organic electroluminescent device according to claim 1, wherein Ar 1 It is represented by a substituted or unsubstituted aromatic hydrocarbon group having 6 to 11 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 11 carbon atoms, or a substituted or unsubstituted linked aromatic group consisting of two to eight linked aromatic groups. The compound for an organic electroluminescent device according to claim 1 , wherein all a's are represented by 0.

7. The compound for an organic electroluminescent device according to claim 1, wherein L 1 and L 2 They are independently represented by a direct bond, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

8. The compound for an organic electroluminescent device according to claim 1, wherein Ad is an adamantyl group represented by the following general formula (3): [Chemistry 3] Here, * represents a bonding point with the general formula (1). 9 . The compound for an organic electroluminescent device according to claim 1 , wherein the glass transition temperature (Tg) is 135° C. or higher.

10. An organic electroluminescent element comprising one or more light-emitting layers between an anode and a cathode facing each other, wherein at least one light-emitting layer comprises a host selected from the compound represented by the general formula (1) as claimed in claim 1 and a light-emitting dopant.

11. The organic electroluminescent element according to claim 10, wherein: As the light-emitting dopant, a light-emitting dopant containing a boron atom is contained.

12. The organic electroluminescent element according to claim 10, wherein: The luminescent dopant includes a polycyclic aromatic compound represented by the following general formula (4a) or (4b), [Chemistry 4] Here, Ring J, Ring K, Ring C, Ring D, Ring E, Ring F, Ring G, and Ring H are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 24 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic ring having 3 to 17 carbon atoms, Y 1 are independently B, P, P=O, P=S, Al, Ga, As, Si-R 3 or Ge-R 3 , R 3 are each independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, X 2 O, N-Ar 4 , S or Se, Ar 4 are independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking two to eight of these groups, N-Ar 4 It may be bonded to any of Ring J, Ring K, Ring C, Ring D, Ring E, Ring F, Ring G, or Ring H to form a heterocyclic ring containing N; R 4 each independently represents a cyano group, a deuterium group, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, a diheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms; g and h represent the number of substitutions and each independently represents an integer of 0 to 4; i and j represent the number of substitutions and each independently represents an integer of 0 to 3; and k represents the number of substitutions and each independently represents an integer of 0 to 2.

13. The organic electroluminescent element according to claim 12, wherein: The general formula (4a) or the general formula (4b) is a polycyclic aromatic compound represented by the following general formula (5a) or the general formula (5b), respectively. [Chemistry 5] Here, X 3 Each independently represents N-Ar 4 , O, or S, at least one X 3 N-Ar 4 ;Ar 4 、R 4 , g, h, i, j, and k have the same meanings as in the case of the general formula (4a) or (4b).

14. The organic electroluminescent element according to claim 13, wherein: The difference (ΔEST) between the excited singlet energy (S1) and the excited triplet energy (T1) of the polycyclic aromatic compounds represented by the general formula (4a), general formula (4b), general formula (5a), and general formula (5b) is 0.20 eV or less.

15. The organic electroluminescent element according to claim 10 comprises one or more light-emitting layers between opposing anodes and cathodes, wherein at least one light-emitting layer comprises a first host selected from the compound represented by the general formula (1), a second host, and a light-emitting dopant comprising a boron atom.

16. The organic electroluminescent element according to claim 15, wherein: The second host is selected from the compounds represented by the following general formula (6): [Chemistry 6] In the general formula (6), Z is a group containing an indole and carbazole ring represented by the general formula (7), and ** represents a group containing an indole and carbazole ring represented by the general formula (7). 3 In addition, the ring A in the general formula (7) is a heterocyclic ring represented by the general formula (8), and the ring A is condensed with the adjacent ring at any position; Among them, L 3 and L 4 are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, Ar 5 and Ar 6 Each of the groups is independently deuterium, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group in which two to eight of these aromatic groups are linked together; R 5 are independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms; v represents the number of substitutions, which is an integer from 1 to 3; w represents the number of substitutions, which is an integer from 0 to 3; q 1 and q 3 represents the number of substitutions, each independently represents an integer from 0 to 4, q 2 represents the number of substitutions, which is an integer from 0 to 2, and r represents the number of substitutions, which is an integer from 0 to 3.

17. The organic electroluminescent element according to claim 16, wherein: The general formula (6) is a compound represented by the following general formula (6a) or general formula (6b), [Chemistry 7] Z, Ar 5 , v and w have the same meanings as in general formula (6), X 4 Indicates O, or S; R 6 Each of them is independently deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms.

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