Compound and organic electroluminescent device

Abstract

To provide a novel blue luminescent material which can realize a narrow emission spectrum and high color purity, and may improve the luminescence efficiency and the lifespan of an organic electroluminescent device.SOLUTION: The invention relates to a compound having a structure in which one structure represented by the general formula 2 is added to a ring-forming atom of Ar1 or a ring-forming atom of Ar2 of a structure represented by the following general formula 1, and in which one to four structures represented by the following general formula 3 are added to at least one of ring-forming atoms of Ar5 and ring-forming atoms of Ar6 of the structure represented by the following general formula 2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a compound and an organic electroluminescent device. [Background technology]

[0002] Organic electroluminescent devices are used in displays for smartphones and other devices, and efforts are being made to improve color purity by utilizing the cavity effect of the top emission method to ensure high color purity. However, while the cavity effect of the top emission method improves color purity, it also comes with the problem of reduced luminous efficiency.

[0003] Currently, fluorescent materials and phosphorescent materials are mainly used as light-emitting materials in organic electroluminescence devices. Three light-emitting materials of red, green, and blue are used in organic electroluminescence devices, and further improvement of blue light-emitting materials is required in terms of light-emitting efficiency, device life, color purity, etc.

[0004] Therefore, in order to improve the luminous efficiency of currently employed top-emission type blue organic electroluminescent elements, there is a demand for a luminescent dopant material that provides organic electroluminescent properties with a narrow half-value width and high efficiency.

[0005] In recent years, it has been reported that luminescent materials such as the following compounds a and b, into which boron atoms have been introduced, emit blue light and exhibit narrow half-widths and high luminous efficiencies in organic EL devices (see Non-Patent Documents 1 and 2).

[0006] [ka] [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] “Ultrapure Blue Thermally Activated Delayed Fluorescence Molecules: Efficient HOMO-LUMO Separation by the Multiple Resonance Effect” Takuji Hatakeyama, Kazushi Shiren, Kiichi Nakajima, Shintaro Nomura, Soichiro Nakatsuka, Keisuke Kinoshita, Jingping Ni, Yohei Ono, and Toshiaki Ikuta, Advanced Materials 2016, 28, 2777-2781 [Non-patent document 2] “Narrowband deep-blue organic light-emitting diode featuring an organoboron-based emitter” Yasuhiro Kondo, Kazuki Yoshiura, Sayuri Kitera, Hiroki Nishi, Susumu Oda, Hajime Gotoh, Yasuyuki Sasada, Motoki Yanai and Takuji Hatakeyama, Nature Photonics 2019, 13, 678-682 Summary of the Invention [Problem to be solved by the invention]

[0008] In organic electroluminescence devices, in order to cover a wide color gamut, light-emitting materials with high color purity are required for each of red, green, and blue (R, G, B).

[0009] However, it is difficult to achieve light emission with high color purity, particularly in blue light-emitting materials, and the materials described in Non-Patent Documents 1 and 2 above have the problem of a wide emission spectrum width and insufficient color purity.

[0010] Therefore, an object of the present invention is to provide a novel blue light-emitting material that has a narrow emission spectrum width, can realize high color purity, and can improve the luminous efficiency and life span of an organic electroluminescence device. [Means for solving the problem]

[0011] The above-mentioned problems of the present invention can be solved by the following means.

[0012] That is, the present invention provides an Ar 1 or Ar 2 and wherein one structure represented by the following general formula 2 is added to a ring-forming atom of Ar of the structure represented by the general formula 2 5 and Ar 6 The compound has a structure in which one to four structures represented by the following general formula 3 are added to at least one of the ring-forming atoms of the compound.

[0013] [ka]

[0014] In the general formula 1, the general formula 2 and the general formula 3, Ar 1 ~Ar 8 are each independently a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, In the general formula 2, X is —O—, —S—, —NR 21 -or-CR 22 R 23 - and R 21 , R 22 and R 23 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and X is -NR 21 -If R 21 Via Ar 7and In the general formula 1, Z is carbon or silicon, In the general formula 2, the two bonds *1 are Ar 1 or two bonds *1 are bonded to the two ring-forming atoms of Ar 2 and bonded to the two ring-forming atoms of In the general formula 3, Y is —O—, —S—, or —NR 31 - and R 31 is hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and the two bonds *2 are Ar 5 or two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 2 6 It bonds to two ring-forming atoms. [Effects of the Invention]

[0015] According to the present invention, a novel blue light-emitting material can be provided which has a narrow emission spectrum width, can realize high color purity, and can improve the luminous efficiency and life span of an organic electroluminescence device. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing an organic electroluminescence element according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view illustrating an organic electroluminescence element according to another embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view illustrating an organic electroluminescence element according to another embodiment of the present invention. [Figure 4] FIG. 1 is an explanatory diagram qualitatively explaining the relationship between the energies. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments. Furthermore, unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20°C to 25°C) and a relative humidity of 40% RH to 50% RH.

[0018] In this specification, the phrase "X and Y are each independently" means that X and Y may be the same or different.

[0019] <Compound> One aspect of the present invention is Ar having a structure represented by the following general formula 1 1 or Ar 2 and wherein one structure represented by the following general formula 2 is added to a ring-forming atom of Ar of the structure represented by the general formula 2 5 and Ar 6 The compound has a structure in which one to four structures represented by the following general formula 3 are added to at least one of the ring-forming atoms of the compound.

[0020] [ka]

[0021] In the general formula 1, the general formula 2 and the general formula 3, Ar 1 ~Ar 8 are each independently a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, In the general formula 2, X is —O—, —S—, —NR 21 -or-CR 22 R 23 - and R 21 , R 22 and R 23 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and X is -NR21 -If R 21 Via Ar 7 and In the general formula 1, Z is carbon or silicon, In the general formula 2, the two bonds *1 are Ar 1 or two bonds *1 are bonded to the two ring-forming atoms of Ar 2 and bonded to the two ring-forming atoms of In the general formula 3, Y is —O—, —S—, or —NR 31 - and R 31 is hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and the two bonds *2 are Ar 5 or two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 2 6 It bonds to two ring-forming atoms.

[0022] Hereinafter, the compound according to the present invention will also be referred to simply as a “fused ring compound” or “the fused ring compound of the present invention.” Furthermore, the organic electroluminescence device will also be referred to simply as an “organic EL device.”

[0023] The fused ring compound according to the present invention has a narrow emission spectrum width, can realize high color purity, and can improve the luminous efficiency and life span of an organic EL device.

[0024] The present inventors presume that the mechanism by which the above configuration solves the problem is as follows.

[0025] The fused ring compounds of the present invention have a nitrogen atom (N) with electron-donating properties and a boron atom (B) with electron-accepting properties, and have a structure in which these atoms are bonded to a conjugated system of a specific structure in an appropriate configuration. All of the fused ring compounds of the present invention have a robust fused ring structure. This structural effect suppresses changes in molecular structure (bond length, bond angle, etc.) between the ground state (S0) and the first excited state (S1), which can cause the emission spectrum to broaden, thereby achieving emission of high color purity with a narrow spectral width, particularly blue emission of high purity with a narrow spectral width. Furthermore, the electronic effect of this configuration also contributes to increasing the oscillator strength, thereby achieving highly efficient emission intensity.

[0026] Furthermore, the fused ring compound of the present invention contains a spiro structure represented by general formula 1 in its mother skeleton, which increases the three-dimensional bulkiness of the molecule and makes it possible to suppress Dexter energy transfer between fused ring compounds, thereby realizing a blue electroluminescent device with a long lifetime.

[0027] Due to these effects, in particular, an organic EL device using the fused ring compound of the present invention and a thermally activated delayed fluorescent material as light-emitting materials can suppress Dexter energy transfer from the light-emitting material (particularly, a phosphorescent material), thereby realizing a highly efficient and long-life blue electroluminescent device.

[0028] The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention. Similarly, the correctness of other speculations in this specification does not affect the technical scope of the present invention.

[0029] The structure represented by the general formula 2 has two bonds *1. The two bonds *1 are the Ar 1 The bonding points or two bonds *1 to the two ring-forming atoms of Ar 2 The fused ring compound of the present invention has one structure represented by the above general formula 2.

[0030] The structure represented by the general formula 3 has two bonds *2. The two bonds *2 are the same as those of Ar in the structure represented by the general formula 2. 5 or the two bonds *2 represent the bonding points with the two ring-forming atoms of Ar 6 The fused ring compound of the present invention has one to four structures represented by the above general formula 3.

[0031] In this specification, the number of ring atoms refers to the number of atoms constituting the ring itself of a compound (e.g., a monocyclic compound, a fused ring compound, a bridged compound, a carbocyclic compound, and a heterocyclic compound) having a structure in which atoms are bonded in a ring (e.g., a monocyclic compound, a fused ring compound, and a ring assembly). The number of ring atoms does not include atoms that do not constitute the ring (e.g., a hydrogen atom terminating the bond of an atom constituting the ring) or atoms contained in the substituent when the ring is substituted with a substituent. The number of ring atoms described below is the same unless otherwise specified.

[0032] For example, a benzene ring has 6 ring atoms, a naphthalene ring has 10 ring atoms, a pyridine ring has 6 ring atoms, and a furan ring has 5 ring atoms.

[0033] When a benzene ring is substituted with, for example, an alkyl group as a substituent, the number of carbon atoms of the alkyl group is not included in the number of ring atoms of the benzene ring. Therefore, the number of ring atoms of a benzene ring substituted with an alkyl group is 6. Furthermore, when a naphthalene ring is substituted with, for example, an alkyl group as a substituent, the number of atoms of the alkyl group is not included in the number of ring atoms of the naphthalene ring. Therefore, the number of ring atoms of a naphthalene ring substituted with an alkyl group is 10.

[0034] For example, the number of hydrogen atoms or atoms constituting a substituent bonded to a pyridine ring is not included in the number of ring atoms of the pyridine ring. Therefore, the number of ring atoms of a pyridine ring to which a hydrogen atom or a substituent is bonded is 6.

[0035] In the above general formula 1, the above general formula 2 and the above general formula 3, Ar 1 ~Ar 8 The aromatic hydrocarbon ring constituting the formula (I) may be a single ring or a fused ring. The number of ring-forming atoms in the aromatic hydrocarbon ring is 6 to 30, preferably 6 to 10, and more preferably 6. Specific examples of aromatic hydrocarbon rings having 6 to 30 ring-forming atoms are not particularly limited, and include, for example, a benzene ring, a pentalene ring, an indene ring, a naphthalene ring, an anthracene ring, an azulene ring, a heptalene ring, an acenaphthalene ring, a phenalene ring, a fluorene ring, a phenanthrene ring, a biphenyl ring, a terphenyl ring, a triphenylene ring, a pyrene ring, a chrysene ring, a picene ring, a perylene ring, a pentaphene ring, a pentacene ring, a tetraphene ring, a hexaphene ring, a hexacene ring, a rubicene ring, a trinaphthylene ring, a heptaphene ring, and a pyranthrene ring. Among these, a benzene ring is preferred.

[0036] In the above general formula 1, the above general formula 2 and the above general formula 3, Ar 1 ~Ar 8 The aromatic heterocycle may be a single ring or a condensed ring. The number of ring atoms in the aromatic heterocycle is 5 to 30, preferably 5 to 20, and more preferably 5 to 18.

[0037] An aromatic heterocycle is a ring having one or more heteroatoms (e.g., nitrogen atom (N), oxygen atom (O), phosphorus atom (P), sulfur atom (S), silicon atom (Si)) as ring-forming atoms, with the remaining ring-forming atoms being carbon atoms (C). Specific examples of aromatic heterocycles having 6 to 30 ring-forming atoms include, but are not limited to, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, an acridine ring, a phenazine ring, a benzoquinoline ring, a benzoisoquinoline ring, a phenanthridine ring, a phenanthroline ring, a benzoquinone ring, a coumarin ring, an anthraquinone ring, a fluorenone ring, a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyrrole ring, an indole ring, a carbazole ring, and an indolocarbazole ring. ring, imidazole ring, benzimidazole ring, pyrazole ring, indazole ring, oxazole ring, isoxazole ring, benzoxazole ring, benzisoxazole ring, thiazole ring, isothiazole ring, benzothiazole ring, benzisothiazole ring, imidazolinone ring, benzimidazolinone ring, imidazopyridine ring, imidazopyrimidine ring, imidazophenanthridine ring, benzimidazophenanthridine ring, azadibenzofuran ring, azacarbazole ring, azadibenzothiophene ring, diazadibenzofuran ring, diazacarbazole ring, diazadibenzothiophene ring, xanthone ring, thioxanthone ring, and the like.

[0038] At least one hydrogen atom in the aromatic hydrocarbon ring and the aromatic heterocycle may be substituted.In this case, the type of the substituent is not particularly limited, but is preferably a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted diheteroarylamino group, or a substituted or unsubstituted arylheteroarylamino group.When two or more hydrogen atoms are substituted, the types of the substituents may be the same or different from each other.

[0039] Examples of the halogen atom as a substituent include a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), and an iodine atom (I).

[0040] The alkyl group as a substituent may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably, for example, 1 to 30, and more preferably 1 to 20. Furthermore, the number of carbon atoms in the alkyl group is even more preferably 1 to 10, and particularly preferably 1 to 6.Specific examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an isobutyl group, a 2-ethylbutyl group, a 3,3-dimethylbutyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group (a t-pentyl group), a cyclopentyl group, a 1-methylpentyl group, a 3-methylpentyl group, a 2-ethylpentyl group, a 4-methyl-2-pentyl group, and an n-hexyl group. , 1-methylhexyl group, 2-ethylhexyl group, 2-butylhexyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-tert-butylcyclohexyl group (4-t-butylcyclohexyl group), n-heptyl group, 1-methylheptyl group, 2,2-dimethylheptyl group, 2-ethylheptyl group, 2-butylheptyl group, n-octyl group, tert-octyl group (t-octyl group), 2-ethyloctyl group, 2-butyloctyl group, 2-hexyloctyl group, 3,7 -dimethyloctyl group, cyclooctyl group, n-nonyl group, n-decyl group, adamantyl group, 2-ethyldecyl group, 2-butyldecyl group, 2-hexyldecyl group, 2-octyldecyl group, n-undecyl group, n-dodecyl group, 2-ethyldodecyl group, 2-butyldodecyl group, 2-hexyldodecyl group, 2-octyldecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, 2-ethylhexadecyl group, 2-butylhexadecyl group, 2- Examples thereof include a hexylhexadecyl group, a 2-octylhexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, an n-icosyl group, a 2-ethylicosyl group, a 2-butylicosyl group, a 2-hexylicosyl group, a 2-octylicosyl group, an n-henicosyl group, an n-docosyl group, an n-tricosyl group, an n-tetracosyl group, an n-pentacosyl group, an n-hexacosyl group, an n-heptacosyl group, an n-octacosyl group, an n-nonacosyl group, and an n-triacontyl group.

[0041] The aryl group as a substituent is not particularly limited, but is preferably, for example, a monovalent group derived from a hydrocarbon ring containing one or more aromatic rings. The hydrocarbon ring constituting the aryl group may be a fused ring. When the aryl group contains two or more aromatic rings, the two or more aromatic rings may be bonded to each other via a single bond (a ring-assembly aromatic hydrocarbon ring). The number of ring atoms of the aryl group is not particularly limited, but is preferably 6 to 30. The number of ring atoms of the aryl group is more preferably 6 to 20, and even more preferably 6 to 18. Specific examples of the aryl group include, but are not limited to, a phenyl group, a naphthyl group, a phenanthryl group, a biphenylenyl group, a triphenylene group, an anthryl group, a pyrenyl group, a fluorenyl group, an azulenyl group, an acenaphthenyl group, a fluoranthenyl group, a naphthacenyl group, a perylenyl group, a pentacenyl group, a quaterphenyl group, and a chrysenyl group.

[0042] The heteroaryl group as a substituent is not particularly limited, but is preferably a monovalent group derived from a ring containing one or more aromatic heterocycles, which has one or more heteroatoms (e.g., nitrogen atom (N), oxygen atom (O), phosphorus atom (P), sulfur atom (S), or silicon atom (Si)) as ring-forming atoms, with the remaining ring-forming atoms being carbon atoms (C). When two or more heteroatoms are contained, the heteroatoms may be the same or different. Furthermore, the rings constituting the heteroaryl group may be fused rings. When the heteroaryl group contains two or more aromatic heterocycles, the two or more aromatic heterocycles may be bonded to each other via a single bond.

[0043] Thus, the heteroaryl group may be a monocyclic heteroaryl group or a polycyclic heteroaryl group. The number of ring atoms in the heteroaryl group is not particularly limited, but is preferably 5 to 30. The number of ring atoms in the heteroaryl group is more preferably 5 to 20, and even more preferably 5 to 18. Specific examples of the heteroaryl group include, but are not limited to, a thienyl group, a furanyl group, a pyrrolyl group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazonyl group, a triazolyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazinyl group, a triazolyl group, an acridinyl group, a pyridazinyl group, a pyridinyl group, a quinolinyl group, a quinazolinyl group, a quinoxalinyl group, a phenoxazinyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinolinyl group, an indolyl group, a kaolin ... Examples of such groups include a rubazolyl group, an N-arylcarbazolyl group, an N-heteroarylcarbazolyl group, an N-alkylcarbazolyl group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzocarbazolyl group, a benzothiophenyl group, a dibenzothienyl group, a thienothienyl group, a benzofuranyl group, a phenanthrolinyl group, a thiazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a phenothiazinyl group, a dibenzosilolyl group, a dibenzofuranyl group, and groups formed from combinations thereof.

[0044] The alkoxy group as a substituent may be linear, branched, or cyclic. The alkyl group constituting the alkoxy group is not particularly limited, but examples thereof include those similar to those described above in the description of the alkyl group as a substituent. The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably 1 or more. The number of carbon atoms in the alkoxy group is preferably 20 or less, more preferably 10 or less, and even more preferably 4 or less. Specific examples of the alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, a sec-butyloxy group, a tert-butyloxy group, an isobutyloxy group, a 2-ethylbutyloxy group, a 3,3-dimethylbutyloxy group, an n-pentyloxy group, an isopentyloxy group, a neopentyloxy group, a tert-pentyloxy group, a cyclopentyloxy group, a 1-methylpentyloxy group, a 3-methylpentyloxy group, a 2-ethylpentyloxy group, a 4-methyl-2-pentyloxy group, an n-hexyloxy group, a 1-methylhexyloxy group, a 2-ethylpentyloxy group, a 4-methyl-2-pentyloxy group, a 2-ethyl ... Examples of such groups include an n-hexyloxy group, a 2-butylhexyloxy group, a cyclohexyloxy group, a 4-methylcyclohexyloxy group, a 4-tert-butylcyclohexyloxy group, an n-heptyloxy group, a 1-methylheptyloxy group, a 2,2-dimethylheptyloxy group, a 2-ethylheptyloxy group, a 2-butylheptyloxy group, an n-octyloxy group, a tert-octyloxy group, a 2-ethyloctyloxy group, a 2-butyloctyloxy group, a 2-hexyloctyloxy group, a 3,7-dimethyloctyloxy group, a cyclooctyloxy group, an n-nonyloxy group, an n-decyloxy group, and an adamantyloxy group.

[0045] The aryloxy group as a substituent is not particularly limited. The number of carbon atoms in the aryloxy group is not particularly limited, but is preferably 6 to 30. The number of carbon atoms in the aryloxy group is more preferably 6 to 12, and even more preferably 6. Specific examples of the aryloxy group are not particularly limited, but include phenyloxy, biphenyloxy, terphenyloxy, naphthyloxy, fluorenyloxy, anthracenyloxy, quaterphenyloxy, quinquephenyloxy, triphenylenyloxy, pyrenyloxy, benzofluorenyloxy, chrysenyloxy, and groups formed from combinations thereof.

[0046] The heteroaryloxy group as a substituent is not particularly limited. The heteroaryl group constituting the heteroaryloxy group is not particularly limited, and examples thereof include the same as those described above in the description of the heteroaryl group. The number of ring-forming atoms in the heteroaryloxy group is not particularly limited, but is preferably 5 to 30. The number of ring-forming atoms in the heteroaryloxy group is more preferably 5 to 14, and even more preferably 5 to 13. The number of heteroatoms as ring-forming atoms in the heteroaryloxy group is not particularly limited, but is preferably 1 to 3. The number of heteroatoms as ring-forming atoms in the heteroaryloxy group is more preferably 1 to 2, and even more preferably 1. Specific examples of the heteroaryloxy group include, but are not limited to, a thienyloxy group, a furanyloxy group, a pyrrolyloxy group, an imidazolyloxy group, a thiazolyloxy group, an oxazolyloxy group, an oxadiazolyloxy group, a triazolyloxy group, a pyridyloxy group, a bipyridyloxy group, a pyrimidyloxy group, a triazinyloxy group, a triazolyloxy group, an acridinyloxy group, a pyridazinyloxy group, a pyridinyloxy group, a quinolinyloxy group, a quinazolinyloxy group, a quinoxalinyloxy group, a phenoxazinyloxy group, a phthalazinyloxy group, a pyridopyrimidinyloxy group, a pyridopyrazinyloxy group, a pyraz ... nopyrazinyloxy group, isoquinolinyloxy group, indolyloxy group, carbazolyloxy group, benzoxazolyloxy group, benzimidazolyloxy group, benzothiazolyloxy group, benzocarbazolyloxy group, benzothiophenyloxy group, dibenzothienyloxy group, thienothienyloxy group, benzofuranyloxy group, phenanthrolinyloxy group, thiazolyloxy group, isoxazolyloxy group, oxadiazolyloxy group, thiadiazolyloxy group, phenothiazinyloxy group, dibenzosilolyloxy group, dibenzofuranyloxy group, xanthonyloxy group, and groups formed from combinations thereof.

[0047] The above-mentioned diarylamino group, diheteroarylamino group, and arylheteroarylamino group as substituents are not particularly limited. Examples of the aryl group and heteroaryl group constituting the diarylamino group, diheteroarylamino group, and arylheteroarylamino group include those described above for the aryl group and heteroaryl group, respectively. Specific examples of the diarylamino group include, but are not limited to, a diphenylamino group, a bis(4-tert-butylphenyl)amino group, a phenyl(naphthyl)amino group, a di(biphenyl)amino group, a di(p-terphenyl)amino group, and the like. Specific examples of the arylheteroarylamino group include, but are not limited to, a phenyl(2-pyridyl)amino group. Specific examples of the diheteroarylamino group include, but are not limited to, a di(2-pyridyl)amino group.

[0048] When the above-mentioned substituents are further substituted, the type of the substituent is not particularly limited. When the above-mentioned substituents are further substituted, examples of the substituent include a deuterium atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted aryl group, an unsubstituted heteroaryl group, an unsubstituted alkoxy group, an unsubstituted aryloxy group, an unsubstituted heteroaryloxy group, an unsubstituted diarylamino group, an unsubstituted diheteroarylamino group, and an unsubstituted arylheteroarylamino group. When the above-mentioned substituents are further substituted, and two or more of the substituents are present, the types of the substituents may be the same or different. Note that the above-mentioned substituents do not substitute the same type of group. For example, the substituents substituting an alkyl group do not include alkyl groups.

[0049] Among the substituents explained above, a phenyl group, a tert-butyl group, a pyridyl group, a pyrrolyl group, a 4-tert-butylphenyl group, a 3-tert-butylphenyl group, a 2-tert-butylphenyl group, a 2-phenylphenyl group, a 2,6-di-isopropylphenyl group, a 3,5-di-tert-butylphenyl group, a 2,6-di-tert-butylphenyl group, a 2,6-diphenylphenyl group, a 2,4-diphenylphenyl group, a 2,5-diphenylphenyl group, a 4-(4-tert-butylphenyl)phenyl group, a 2,6-bis(4-tert-butylphenyl)phenyl group, a 2,6-bis(3-tert-butylphenyl)phenyl group, a 4-(3,5-di-tert-butylphenyl)phenyl group, a 2,6-bis(3,5-di-tert-butylphenyl)phenyl group, a 4-tert-butyl-2,6-bis(4-tert-butylphenyl)phenyl group, Preferred are a 2,4,5-triphenylphenyl group, a 2,4,6-triphenylphenyl group, a 2,4,6-tri-tert-butylphenyl group, a 4-(4-tert-butylphenyl)-2,5-diphenylphenyl group, a 4-(3,5-di-tert-butylphenyl)-2,5-diphenylphenyl group, a 5-tert-butyl-2,4-diphenylphenyl group, a 4-phenyl-2,6-di-tert-butylphenyl group, a 4-phenyl-2,5-di-tert-butylphenyl group, a carbazolyl group, a 1,8-dimethylcarbazolyl group, a 1,8-dimethyl-3,6-di-tert-butylcarbazolyl group, a 3,6-di-tert-butylcarbazolyl group, a diphenylamino group, a bis(2,6-dimethylphenyl)amino group, a bis(2,6-dimethyl-4-tert-butylphenyl)amino group, and a bis(4-tert-butylphenyl)amino group.

[0050] In the above general formula 2, X is —O—, —S—, —NR 21 -or-CR 22 R 23 - and R 21 , R 22 and R 23are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and X is -NR 21 -If R 21 Via Ar 7 Specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given above in the description of the substituents.

[0051] In the above general formula 1, Z is carbon or silicon. Z is preferably carbon.

[0052] In the above general formula 3, Y is —O—, —S—, or —NR 31 - and R 31 is hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. Specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given in the description of the substituents above.

[0053] The fused ring compound of the present invention is Ar of the structure represented by the above general formula 1 1 or Ar 2 and wherein one structure represented by the following general formula 4 is added to a ring-forming atom of Ar having a structure represented by the following general formula 4 5’ and Ar 6 Preferably, the compound has a structure in which one to four structures represented by the following general formula 5 are added to at least one of the ring-forming atoms of the above.

[0054] [ka]

[0055] In the above general formula 4, R 41is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; n is 0, 1, 2, or 3, where when n is 2 or more, R 41 may be the same or different, Ar 6 , Ar 7 , X and the bond *1 are defined as in the general formula 2 above, In the above general formula 5, Ar 9 is a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, The two bonds *2 are Ar in the structure represented by the general formula 5. 5’ or two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 5. 6 and bonded to the two ring-forming atoms of Ar 8 has the same meaning as that explained in the above general formula 3.

[0056] R in the above general formula 4 41 In the above, specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given in the description of the substituents.

[0057] Ar in the above general formula 5 9 In the above, specific examples of the aromatic hydrocarbon ring and aromatic heterocycle are the same as the specific examples of the aromatic hydrocarbon ring and aromatic heterocycle in the above general formula 1, the above general formula 2 and the above general formula 3.

[0058] The fused ring compound of the present invention is Ar of the structure represented by the above general formula 1 1 or Ar 2 It is more preferable that the compound has a structure in which one structure represented by the following general formula 6 is added to a ring-forming atom of the above.

[0059] [ka]

[0060] In the above general formula 6, R 61 is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; m is 0 or 1, Ar 6 , Ar 7 , X and the bond *1 are defined as in the general formula 2, and Ar 8 is the same as defined in the general formula 3, and Ar 9 has the same meaning as that explained in the general formula 5 above.

[0061] R in the above general formula 6 61 In the above, specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given in the description of the substituents.

[0062] The fused ring compound of the present invention is Ar of the structure represented by the above general formula 1 1 or Ar 2 It is more preferable that the compound has a structure in which one structure represented by the following general formula 7 is added to a ring-forming atom of the above.

[0063] [ka]

[0064] In the above general formula 7, R 71 is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; o is 0, 1, 2, 3 or 4, where when o is 2 or more, R 71 may be the same or different, X and the bond *1 are defined as in the general formula 2, and Ar 8 is the same as defined in the general formula 3, and Ar 9 is the same as defined in the general formula 5, and R 61 and m have the same meanings as those in the general formula 6.

[0065] R in the above general formula 7 71 In the above, specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given in the description of the substituents.

[0066] In the above general formula 7, R 72 is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; p is 0, 1, 2, or 3, where, when p is 2 or more, R 72 may be the same or different, R in the above general formula 7 72 The introduction of electron donating or withdrawing groups as R affects the spectral shape. 72 In the above, specific examples of the alkyl group, aryl group, and heteroaryl group are the same as the specific examples of the alkyl group, aryl group, and heteroaryl group given in the description of the substituents.

[0067] Compounds 1 to 109, which are fused ring compounds according to one embodiment of the present invention, are specifically exemplified below, although the present invention is not limited to these specific examples.

[0068] [ka]

[0069] [ka]

[0070]

change

[0071]

change

[0072]

change

[0073]

change

[0074]

change

[0075]

change

[0076]

change

[0077] Among these, Compound 1, Compound 2, Compound 3, Compound 4, Compound 5, Compound 6, Compound 7, Compound 8, Compound 9, Compound 10, Compound 11, Compound 12, Compound 13, Compound 14, Compound 18, Compound 20, Compound 26, Compound 27, Compound 28, Compound 31, Compound 32, Compound 33, Compound 34, Compound 36, Compound 37, Compound 38, Compound 39, Compound 42, Compound 43, Compound 44, Compound 45, Compound 46, Compound 48, Compound 49, Compound 50, Compound 51, Compound 52, Compound 53, Compound 54, Compound 55, Compound 56, Compound 57, Compound 58, Compound 59, Compound 60, Compound 61, Compound 62, Compound 63, Compound 64, Compound Compound 65, Compound 66, Compound 67, Compound 68, Compound 69, Compound 70, Compound 71, Compound 72, Compound 73, Compound 74, Compound 75, Compound 76, Compound 77, Compound 78, Compound 79, Compound 80, Compound 81, Compound 82, Compound 86, Compound 87, Compound 88, Compound 89, Compound 90, Compound 91, Compound 92, Compound 93, Compound 94, Compound 95, Compound 99, Compound 101, Compound 102, Compound 103, Compound 104, Compound 105, Compound 106, and Compound 107. At least one selected from the group consisting of Compound 1, Compound 2, Compound 3, and Compound 4 is particularly preferred.

[0078] In the fused ring compound of the present invention, the peak of the fluorescence wavelength obtained by converting the adiabatic first excited singlet state (S1) energy (hereinafter also referred to as "adiabatic S1 excitation energy") (eV) to the light wavelength (nm), the oscillator strength f in the stable structure of the adiabatic first excited singlet state (S1), and the rearrangement energy can be calculated by density functional theory (DFT) using Gaussian 16 (Gaussian Inc.) as calculation software. Details of each calculation method are described in the Examples.

[0079] The peak of the fluorescence wavelength obtained by converting the adiabatic S1 excitation energy (eV) calculated using density functional theory to the light wavelength (nm) is not particularly limited. Here, the peak of the fluorescence wavelength is preferably 360 nm or more and 515 nm or less. Furthermore, the peak of the fluorescence wavelength is more preferably 380 nm or more and 505 nm or less, and even more preferably 400 nm or more and 500 nm or less. Furthermore, the peak of the fluorescence wavelength is even more preferably 420 nm or more and 490 nm or less. And, the peak of the fluorescence wavelength is particularly preferably 430 nm or more and 480 nm or less. Within the above ranges, good light emission, especially good blue light emission, can be obtained.

[0080] The oscillator strength f in the stable structure of the adiabatic first excited singlet state (S1) calculated using density functional theory is not particularly limited, but is preferably 0.22 or more. Furthermore, the oscillator strength f is more preferably 0.30 or more. Furthermore, the oscillator strength f is even more preferably 0.40 or more, and particularly preferably 0.50 or more. It is believed that a higher fluorescence emission intensity can be obtained within the above range. The theoretical upper limit of the oscillator strength f is the number of electrons contained in the molecule. The upper limit of the oscillator strength f may be, for example, 2.00 or 3.00, but is not particularly limited to these values.

[0081] The rearrangement energy calculated using density functional theory is, for example, 0.11 eV or less, preferably 0.10 eV or less. The rearrangement energy is more preferably 0.09 eV or less. The rearrangement energy is further preferably 0.07 eV or less, particularly preferably 0.06 eV or less (lower limit: 0 eV). Within the above range, it is believed that emission with a narrower emission spectrum width and high color purity can be obtained.

[0082] In the fused ring compound of the present invention, the peak of the fluorescence wavelength obtained by converting the adiabatic S1 excitation energy (eV) to the light wavelength (nm) is not particularly limited. Here, the peak of the fluorescence wavelength is preferably 360 nm or more and 515 nm or less. Furthermore, the peak of the fluorescence wavelength is more preferably 380 nm or more and 505 nm or less, and even more preferably 400 nm or more and 500 nm or less. Furthermore, the peak of the fluorescence wavelength is even more preferably 420 nm or more and 490 nm or less. Furthermore, the peak of the fluorescence wavelength is particularly preferably 430 nm or more and 480 nm or less, and most preferably 440 nm or more and 470 nm or less. Within the above ranges, good light emission, particularly good blue light emission, can be obtained.

[0083] Furthermore, the preferred range of the peak wavelength of fluorescent emission in photoluminescence (PL) is the same as the preferred range of the peak fluorescent wavelength obtained by converting the above-mentioned adiabatic S1 excitation energy into light wavelength.

[0084] In the fused ring compound of the present invention, the spectral width of the fluorescent emission in photoluminescence (PL) (full width at half maximum of the peak of the fluorescent emission spectrum, FWHM) is not particularly limited, but the narrower the better. Specifically, the spectral width of the fluorescent emission in PL is preferably 30 nm or less, and more preferably 25 nm or less (the lower limit is greater than 0 nm). Within the above range, light emission with higher color purity can be obtained.

[0085] In the fused ring compound of the present invention, the oscillator strength f in the stable structure of the adiabatic first excited singlet state (S1) is not particularly limited, but is preferably 0.22 or more. Furthermore, the oscillator strength f is more preferably 0.30 or more. Furthermore, the oscillator strength f is further preferably 0.40 or more, and particularly preferably 0.50 or more. It is believed that a higher fluorescence emission intensity can be obtained within the above range. The theoretical upper limit of the oscillator strength f is the number of electrons contained in the molecule. The upper limit of the oscillator strength f may be, for example, 2.0 or 3.0, but is not particularly limited thereto.

[0086] In the fused ring compound of the present invention, the rearrangement energy is preferably 0.1 eV or less. Furthermore, the rearrangement energy is more preferably 0.08 eV or less, and even more preferably 0.07 eV or less. Furthermore, the rearrangement energy is particularly preferably less than 0.065 eV, and extremely preferably 0.06 eV or less (lower limit: 0 eV). It is believed that within the above range, emission with a narrower emission spectrum and high color purity can be obtained.

[0087] The singlet energy S1, triplet energy T1, PL fluorescence emission peak wavelength, and fluorescence emission spectral width (FWHM) can each be actually measured using a spectrofluorometer F-7000 manufactured by Hitachi High-Tech Science Corp. Details of the measurement method are described in the Examples.

[0088] The synthesis method of the fused ring compound according to one embodiment of the present invention is not particularly limited, and the compound can be synthesized based on the knowledge of known synthesis methods. More specifically, the compound can be synthesized by the method described in the Examples or in accordance with the method described in the Examples. For example, the compound can be synthesized by changing the raw materials, reaction conditions, etc., in the method described in the Examples, adding or excluding some steps, or appropriately combining known synthesis methods.

[0089] For example, the above compounds 1 to 4 can be synthesized by the methods described in the Examples.

[0090] The method for confirming the structure of the fused ring compound according to one embodiment of the present invention is not particularly limited, and the structure of the fused ring compound according to one embodiment of the present invention can be confirmed by, for example, a known method (e.g., NMR, LC-MS, etc.).

[0091] [Materials for organic electroluminescence devices] Another embodiment of the present invention relates to a material for an organic electroluminescence device, comprising the fused ring compound of the present invention. The material for an organic electroluminescence device according to one embodiment of the present invention (hereinafter also simply referred to as "material for an organic EL device") preferably comprises the above-mentioned fused ring compound and other materials used in an organic EL device.

[0092] The other materials used in the organic EL device are not particularly limited and include known materials. For example, the other materials used in the organic EL device can be those mentioned as materials constituting each layer in the description of the organic EL device below. Among these, at least one of a dopant material and a host material, which will be mentioned in the description of the light-emitting layer of the organic EL device below, is preferred. Furthermore, at least one selected from the group consisting of a thermally activated delayed fluorescent material (TADF material, TADF compound), a phosphorescent material (phosphorescent compound), and a host material, which will be mentioned in the description of the light-emitting layer of the organic EL device below, is more preferred. Furthermore, a host material, or a TADF material or a phosphorescent material and a host material, is even more preferred. A TADF material or a phosphorescent material and a host material are particularly preferred. Furthermore, a phosphorescent material and a host material are extremely preferred. Here, the phosphorescent material is preferably a phosphorescent complex, which will be mentioned in the description of the light-emitting layer of the organic EL device below. Furthermore, a platinum complex, which will be mentioned in the description of the light-emitting layer of the organic EL device below, is more preferred.

[0093] Thus, a preferred embodiment of the present invention is a material for an organic EL device that further comprises, in addition to the fused ring compound of the present invention, at least one of a TADF material and a phosphorescent material, which will be described later. In this case, the phosphorescent material is preferably a phosphorescent complex, and more preferably a platinum complex, which will be described later. By including, in the material for an organic EL device, particularly the material for the light-emitting layer, at least one of a TADF material and a phosphorescent material, in addition to the fused ring compound of the present invention, the light-emitting efficiency and device life of the organic EL device can be significantly improved. The reason for this is as will be described later in the description of the light-emitting layer of the organic EL device.

[0094] In one embodiment of the present invention, the material for an organic EL device may be a liquid material further containing a solvent. The solvent is not particularly limited, but is preferably a solvent having a boiling point of 100°C or higher and 350°C or lower at atmospheric pressure (101.3 kPa, 1 atm). The boiling point of the solvent at atmospheric pressure is more preferably 150°C or higher and 320°C or lower, and even more preferably 180°C or higher and 300°C or lower. When the boiling point of the solvent at atmospheric pressure is within the above range, film-forming properties and processability in wet film-forming methods, particularly inkjet methods, are improved.

[0095] The solvent having a boiling point of 100° C. or higher and 350° C. or lower at atmospheric pressure is not particularly limited, and known solvents can be appropriately used. Specific examples of solvents having a boiling point of 100° C. or higher and 350° C. or lower at atmospheric pressure are listed below, but the present invention is not limited to these specific examples.

[0096] Examples of hydrocarbon solvents include octane, nonane, decane, undecane, dodecane, etc. Examples of aromatic hydrocarbon solvents include toluene, xylene, ethylbenzene, n-propylbenzene, iso-propylbenzene, mesitylene, n-butylbenzene, sec-butylbenzene, 1-phenylpentane, 2-phenylpentane, 3-phenylpentane, phenylcyclopentane, phenylcyclohexane, 2-ethylbiphenyl, 3-ethylbiphenyl, etc. Examples of ether solvents include 1,4-dioxane, 1,2-diethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, anisole, ethoxybenzene, 3-methylanisole, m-dimethoxybenzene, etc. Examples of ketone solvents include 2-hexanone, 3-hexanone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, cycloheptanone, etc.Examples of ester-based solvents include butyl acetate, butyl propionate, butyl heptylbutyrate, propylene carbonate, methyl benzoate, ethyl benzoate, 1-propyl benzoate, and 1-butyl benzoate. Examples of nitrile-based solvents include benzonitrile and 3-methylbenzonitrile. Examples of amide-based solvents include dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. These solvents may be used alone or in combination of two or more.

[0097] The material for an organic EL device according to one embodiment of the present invention is preferably a material for a light-emitting layer.

[0098] As a preferred embodiment of the material for an organic EL device according to the present invention, for example, the material for an organic EL device described above that is not a liquid composition (that is, that does not substantially contain a solvent) can be mentioned. Even when the material for an organic EL device is not a liquid composition, the material for an organic EL device is preferably a material for an emitting layer.

[0099] Here, "substantially free of solvent" means that the content of solvent in the material is less than 1% by mass relative to the total mass of the composition. When the material for an organic EL device is not a liquid composition, it preferably contains substantially no solvent, and more preferably contains no solvent at all (0% by mass relative to the total mass of the composition).

[0100] The preferred content of the above-mentioned fused ring compound relative to the total mass of the material for an organic EL device (particularly, the material for an emitting layer) (total mass excluding the solvent in the case of a liquid composition) is the same as the preferred content of the above-mentioned fused ring compound relative to the total mass of the emitting layer in the emitting layer of an organic EL device described below.

[0101] Furthermore, the preferred content of the TADF material or phosphorescent material (preferably, phosphorescent material) relative to the total mass of the material for the organic EL device (particularly, the material for the light-emitting layer) (total mass excluding the solvent in the case of a liquid composition) is the same as the preferred content of at least one of the TADF material and the phosphorescent material (preferably, phosphorescent material) relative to the total mass of the light-emitting layer in the light-emitting layer of an organic electroluminescence device described below.

[0102] The preferred content (parts by mass) of the TADF material or phosphorescent material (preferably, phosphorescent material) relative to 100 parts by mass of the fused ring compound of the present invention in the material for an organic EL device (particularly, the material for an emitting layer) is also the same as the preferred content (parts by mass) of the TADF material or phosphorescent material (preferably, phosphorescent material) relative to 100 parts by mass of the fused ring compound of the present invention in the emitting layer of an organic EL device described below.

[0103] The preferred content of the host material relative to the total mass of the materials for the organic EL device (particularly, the materials for the light-emitting layer) (total mass excluding the solvent in the case of a liquid composition) is the same as the preferred content of the host material relative to the total mass of the light-emitting layer in the light-emitting layer of the organic EL device described below.

[0104] The preferred content (parts by mass) of the host material relative to 100 parts by mass of the fused ring compound of the present invention in the material for an organic EL device (particularly, the material for the light-emitting layer) is also the same as the preferred content (parts by mass) of the host material relative to 100 parts by mass of the fused ring compound of the present invention in the light-emitting layer of an organic EL device described below.

[0105] When the amounts of the fused ring compound, the TADF material or the phosphorescent material, and the host material added in the material for an organic electroluminescence device (particularly, the material for an emitting layer) are within the above-mentioned ranges, an organic EL device having superior color purity of emitted light, higher luminous efficiency, and longer life can be obtained.

[0106] <Composition> Another aspect of the present invention relates to a composition comprising the above-described fused ring compound. The composition according to one embodiment of the present invention preferably comprises the above-described fused ring compound and other materials used in organic electroluminescence devices.

[0107] The types of other materials used in the organic electroluminescence device, the preferred contents of other materials in the composition, etc. are the same as those explained in the section [Materials for organic electroluminescence device] above, and therefore will not be explained here.

[0108] According to a preferred embodiment of the present invention, a composition is provided that further comprises, in addition to the above-described fused ring compound, at least one of the above-described TADF material and phosphorescent material. In this case, the phosphorescent compound is preferably a phosphorescent complex, more preferably a platinum complex. By including a TADF material or a phosphorescent material in an organic electroluminescent device material, particularly an emitting layer material, in addition to the above-described fused ring compound, the luminous efficiency and device life of the organic electroluminescent device can be significantly improved. The reason for this is as described below in the description of the emitting layer.

[0109] <Organic electroluminescence element> Another aspect of the present invention relates to an organic electroluminescence device having an organic layer containing the above-mentioned fused ring compound. Such an organic electroluminescence device can achieve light emission with a narrow emission spectrum and high color purity, as well as high luminous efficiency and a long life.

[0110] The organic EL element according to this embodiment will be described in detail below with reference to the drawings. Figures 1 to 3 are schematic diagrams showing the organic electroluminescence element according to this embodiment.

[0111] 1 to 3 are cross-sectional views each showing an organic electroluminescence element according to one embodiment of the present invention, but the structure of the organic electroluminescence element according to the present invention is not limited to the forms shown in FIGS.

[0112] 1 is a cross-sectional view showing an organic electroluminescent device according to one embodiment of the present invention. The organic electroluminescent device 10 according to one embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order.

[0113] Fig. 2 is a cross-sectional view showing an organic electroluminescent element according to another embodiment of the present invention. An organic electroluminescent element 10 according to one embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order. In Fig. 2, the hole transport region 3 includes a hole injection layer 31 and a hole transport layer 32, which are stacked in this order. Also, in Fig. 2, the electron transport region 5 includes an electron transport layer 52 and an electron injection layer 51, which are stacked in this order.

[0114] Fig. 3 is a cross-sectional view showing an organic electroluminescent device according to another embodiment of the present invention. An organic electroluminescent device 10 according to one embodiment of the present invention includes a substrate 1, a first electrode 2, a hole transport region 3, an emitting layer 4, an electron transport region 5, and a second electrode 6, which are stacked in this order. In Fig. 3, the hole transport region 3 includes a hole injection layer 31, a hole transport layer 32, and an electron blocking layer 33, which are stacked in this order. Also, in Fig. 3, the electron transport region 5 includes a hole blocking layer 53, an electron transport layer 52, and an electron injection layer 51, which are stacked in this order.

[0115] The fused ring compound according to the present invention is contained, for example, in any of the organic layers disposed between the first electrode 2 and the second electrode 6. Examples of the organic layer include a hole injection layer 31, a hole transport layer 32, an emissive layer 4, an electron transport layer 52, and an electron injection layer 51. The fused ring compound according to the present invention is more preferably contained in the emissive layer 4.

[0116] An embodiment of the present invention includes, for example, an organic electroluminescent device including a first electrode, a second electrode, and one or more light-emitting layers, the second electrode being preferably disposed on top of the first electrode.

[0117] In this specification, when a layer, film, region, plate, or other portion is described as being "on" or "above" another portion, this includes not only the case where it is "directly above" the other portion, but also the case where there is another portion between them. Conversely, when a layer, film, region, plate, or other portion is described as being "below" or "below" another portion, this includes not only the case where it is "directly below" the other portion, but also the case where there is another portion between them. Furthermore, in this specification, being "located on" includes not only the case where it is located on the top, but also the case where it is located on the bottom or lower surface.

[0118] As described above, the fused ring compound of the present invention is preferably contained in the light-emitting layer. That is, the organic layer is preferably a light-emitting layer. Hereinafter, an embodiment in which the fused ring compound of the present invention is contained in the light-emitting layer will be described. The fused ring compound of the present invention contained in the light-emitting layer may be one type alone or two or more types in combination.

[0119] <Light-emitting layer> The light-emitting layer may be a single layer made of a single material, a single layer made of multiple different materials, or a multilayer structure having multiple layers made of multiple different materials.

[0120] The content of the fused ring compound relative to the total mass of the light-emitting layer is not particularly limited, but is preferably 0.05% by mass or more. Furthermore, this content is more preferably 0.1% by mass or more, and even more preferably 0.2% by mass or more. Furthermore, the content of the fused ring compound relative to the total mass of the light-emitting layer is preferably 50% by mass or less. Furthermore, this content is more preferably 30% by mass or less, and even more preferably 25% by mass or less. Within these ranges, an organic electroluminescence device with superior color purity of light emission, higher luminous efficiency, and longer life can be obtained.

[0121] The light-emitting layer is not particularly limited, and may contain, for example, a host material and a dopant material. The fused ring compound may be used as either the host material or the dopant material, but is preferably used as the dopant material.

[0122] The light-emitting layer is not particularly limited, and may contain, for example, a known light-emitting layer material, such as an anthracene derivative, a pyrene derivative, a fluoranthene derivative, a chrysene derivative, a dihydrobenzoanthracene derivative, or a triphenylene derivative, in addition to the above-mentioned fused ring compound.

[0123] Furthermore, the light-emitting layer preferably contains a known thermally activated delayed fluorescence material (TADF compound) in addition to the above-mentioned fused ring compound. Thermally activated delayed fluorescence refers to a phenomenon in which reverse intersystem crossing from triplet excitons to singlet excitons occurs in a compound with a small energy difference (ΔEst) between the singlet and triplet levels. A TADF material refers to a material in which such a phenomenon occurs.

[0124] Examples of TADF materials include the following compounds:

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] These TADF materials may be used alone or in combination of two or more.

[0129] In addition to the fused ring compound, the light-emitting layer preferably contains a phosphorescent material (phosphorescent compound). The phosphorescent material (phosphorescent compound) is not particularly limited, and any known compound exhibiting phosphorescence can be used. Among these, phosphorescent complexes are preferred, and platinum complexes are more preferred.

[0130] Examples of phosphorescent materials (phosphorescent compounds) include the following compounds.

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] These phosphorescent materials (phosphorescent compounds) may be used singly or in combination of two or more.

[0136] The luminous efficiency and lifetime of an organic EL device can be significantly improved by including at least one of a TADF material and a phosphorescent material in the light-emitting layer in addition to the fused ring compound of the present invention. The reason for this is presumed to be as follows.

[0137] As is well known, in the emissive layer of an organic electroluminescent device, singlet and triplet excitons are generated in a ratio of 1:3 due to the recombination of holes and electrons. In devices containing only fluorescent materials as emissive materials, only singlet excitons are involved in light emission, whereas devices containing TADF or phosphorescent materials as emissive materials can utilize both singlet and triplet excitons for light emission. This significantly improves the luminous efficiency of these devices. Meanwhile, excitons generated in TADF or phosphorescent materials typically have a long lifetime of 1 μs or more. Excitons are highly energetic and unstable. Therefore, their presence can cause material degradation, leading to a shortened device lifetime. When a TADF or phosphorescent material is present in the emissive layer in addition to the fused ring compound, excitons are generated efficiently on the TADF or phosphorescent material. Furthermore, energy is transferred from the exciton to the fused ring compound via the FRET (Foe (lowercase o with an umlaut) First Resonance Energy Transfer) mechanism. As a result, highly efficient fluorescence emission from the fused ring compound is obtained, and the time that the excitons remain on the TADF material or phosphorescent material is shortened. This significantly reduces the possibility of material degradation and significantly improves the device lifespan.

[0138] The content of at least one of the TADF material and the phosphorescent material (preferably the phosphorescent material) relative to the total mass of the light-emitting layer is not particularly limited, but is preferably 0.1% by mass or more. The content is more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. The content is even more preferably 3% by mass or more, and particularly preferably 5% by mass or more. The content of at least one of the TADF material and the phosphorescent material (preferably the phosphorescent material) relative to the total mass of the light-emitting layer is preferably 50% by mass or less. The content is more preferably 40% by mass or less, and even more preferably 30% by mass or less. When the light-emitting layer contains both the TADF material and the phosphorescent material, the total content of these materials is preferably within the above-mentioned range. Within these ranges, an organic EL device with superior color purity of light emission, higher luminous efficiency, and longer life can be obtained.

[0139] When the light-emitting layer contains at least one of a TADF material and a phosphorescent material (preferably a phosphorescent material), the content is not particularly limited, but is preferably 100 parts by mass or more relative to 100 parts by mass of the fused ring compound. The content is more preferably 150 parts by mass or more, and even more preferably 200 parts by mass or more, relative to 100 parts by mass of the fused ring compound. The content of at least one of a TADF material and a phosphorescent material (preferably a phosphorescent material) is preferably 10,000 parts by mass or less relative to 100 parts by mass of the fused ring compound. The content is more preferably 7,500 parts by mass or less, and even more preferably 5,000 parts by mass or less, relative to 100 parts by mass of the fused ring compound. When the light-emitting layer contains both a TADF material and a phosphorescent material, the total content of these materials is preferably within the above-mentioned range. Within these ranges, an organic EL device with superior color purity of emitted light, higher luminous efficiency, and longer life can be obtained.

[0140] The light-emitting layer is not particularly limited, and may contain, for example, a known host material, such as at least one of DPEPO (bis[2-(diphenylphosphino)phenyl]etheroxide), CBP (4,4'-bis(carbazol-9-yl)biphenyl), mCBP (3,3'-bis(carbazol-9-yl)biphenyl), mCP (1,3-bis(carbazol-9-yl)benzene), PPF (2,8-bis(diphenylphosphoryl)dibenzo[b,d]furan), TcTa (4,4',4''-tris(carbazol-9-yl)triphenylamine), and TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene). However, the light-emitting layer is not limited thereto, and examples thereof include Alq3 (tris(8-hydroxyquinolino)aluminum), CBP (4,4'-bis(N-carbazolyl)-1,1'-biphenyl), PVK (poly(n-vinylcarbazole)), ADN (9,10-di(naphthalen-2-yl)anthracene), TCTA (4,4',4"-tris(carbazol-9-yl)-triphenylamine), TPBi (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene), TBADN (3-tert-butyl-9,10-di(naphth-2-yl)anthracene), DSA (distyrylaryl) and the like. The compound may include, for example, 4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl), CDBP (4,4'-bis(9-carbazolyl)-2,2'-dimethyl-biphenyl), MADN (2-methyl-9,10-bis(naphthalen-2-yl)anthracene), DPEPO (bis[2-(diphenylphosphino)phenyl]etheroxide), CP1 (hexaphenylcyclotriphosphazene), UGH2 (1,4-bis(triphenylsilyl)benzene), DPSiO3 (hexaphenylcyclotrisiloxane), DPSiO4 (octaphenylcyclotetrasiloxane), or PPF (2,8-bis(diphenylphosphoryl)dibenzofuran).

[0141] The light-emitting layer preferably contains a host material having a HOMO of -5.2 eV or less. The light-emitting layer preferably contains a host material having a LUMO of -1.4 eV or less. The use of a host material with low HOMO and LUMO and high electron transport properties offers advantages such as improved driving durability in organic electroluminescent devices, particularly blue organic electroluminescent devices. Such a material is not particularly limited, but a preferred example includes a compound represented by the following chemical formula A, which is disclosed in “An Alternative Host Material for Long-Lifespan Blue Organic Light-Emitting Diodes Using Thermally Activated Delayed Fluorescence” by Soo-Ghang Ihn, Namheon Lee, Soon Ok Jeon, Myungsun Sim, Hosuk Kang, Yongsik Jung, Dal Ho Huh, Young Mok Son, Sae Youn Lee, Masaki Numata, Hiroshi Miyazaki, Rafael Gomez-Bombarelli, Jorge Aguilera-Iparraguirre, Timothy Hirzel, Al Aspuru-Guzik, Sunghan Kim, and Sangyoon Lee, Advanced Science News 2017, 4, 1600502. When a light-emitting layer is formed by combining a conventional blue-emitting material with such a host material, it may become a deep hole trap, resulting in undesirable effects such as an increase in driving voltage, etc. On the other hand, the fused ring compound of the present invention has a weak hole trapping property and is expected to act to suppress the occurrence of an increase in driving voltage, etc.

[0142] [ka]

[0143] The light-emitting layer may contain the following compounds as a host material.

[0144] [ka]

[0145] Among these, the light-emitting layer preferably contains at least one of the above compound HT1 and the above compound HT2 as the host material, and more preferably contains both the above compound HT1 and the above compound HT2.

[0146] The content of the host material relative to the total mass of the light-emitting layer is not particularly limited, but is preferably 5% by mass or more. Furthermore, this content is more preferably 10% by mass or more, and even more preferably 20% by mass or more. Furthermore, the content of the host material relative to the total mass of the light-emitting layer is preferably 99% by mass or less. Furthermore, this content is more preferably 95% by mass or less, and even more preferably 90% by mass or less. Within these ranges, an organic EL device with superior color purity of light emission, higher luminous efficiency, and longer life can be obtained.

[0147] When the light-emitting layer contains a host material, its content is not particularly limited, but is preferably 1,000 parts by mass or more per 100 parts by mass of the fused ring compound. Furthermore, the content is more preferably 2,000 parts by mass or more, and even more preferably 3,000 parts by mass or more, per 100 parts by mass of the fused ring compound. Furthermore, the content of the host material is preferably 200,000 parts by mass or less per 100 parts by mass of the fused ring compound. Furthermore, the content is more preferably 150,000 parts by mass or less, and even more preferably 100,000 parts by mass or less, per 100 parts by mass of the fused ring compound. Within these ranges, an organic electroluminescent device with superior color purity of emitted light, higher luminous efficiency, and longer life can be obtained.

[0148] The light-emitting layer is not particularly limited, and may contain, for example, a known dopant material, such as a styryl derivative (e.g., 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB), 4-(di-p-tolylamino)-4'-[(di-p-tolylamino)styryl]stilbene (DPAVB), N-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalen-2-yl)vinyl)phenyl)-N-phenylbenzenamine (N-BDAVBi)), perylene or a derivative thereof (e.g., 2,5,8,11-tetra-tert-butylperylene (TBP)), or pyrene or a derivative thereof (e.g., 1,1-dipyrene, 1,4-dipyrenylbenzene, 1,4-bis(N,N-diphenylamino)pyrene).

[0149] The light-emitting layer may be a single layer made of a single material, a single layer made of multiple different materials, or a multilayer structure having multiple layers made of multiple different materials.

[0150] The thickness of the light-emitting layer is not particularly limited, but is preferably 1 nm or more and 100 nm or less, and more preferably 10 nm or more and 30 nm or less.

[0151] The emission wavelength of the light-emitting layer (i.e., the emission wavelength of an organic electroluminescent device having the light-emitting layer) is not particularly limited. However, it is preferable that the light-emitting layer emits light having a peak in the wavelength range of 360 nm or more and 515 nm or less. It is more preferable that the light-emitting layer emits light having a peak in the wavelength range of 380 nm or more and 505 nm or less. It is even more preferable that the light-emitting layer emits light having a peak in the wavelength range of 400 nm or more and 500 nm or less. It is even more preferable that the light-emitting layer emits light having a peak in the wavelength range of 420 nm or more and 470 nm or less. It is particularly preferable that the light-emitting layer emits light having a peak in the wavelength range of 430 nm or more and 465 nm or less. Within the above ranges, good light emission, particularly good blue light emission, can be obtained.

[0152] The spectral width of the light emitted from the light-emitting layer (full width at half maximum of the peak of the emission spectrum, FWHM) (i.e., the spectral width of the light emitted from an organic electroluminescent device having the light-emitting layer) is not particularly limited, but the narrower the better. Specifically, the spectral width of the light emitted is preferably 30 nm or less, more preferably 25 nm or less, and even more preferably 24 nm or less (lower limit: greater than 0 nm). Within the above range, light emission with higher color purity can be obtained.

[0153] The method for forming the light-emitting layer is not particularly limited, and examples thereof include known film-forming methods such as vacuum deposition, spin coating, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, and laser induced thermal imaging (LITI).

[0154] Next, the substrate, and each region and layer will be described in detail.

[0155] (Substrate 1) The organic EL element 10 may have a substrate 1. A substrate used in a general organic electroluminescent element can be used as the substrate 1. For example, the substrate 1 may be a glass substrate, a semiconductor substrate such as a silicon substrate, or a transparent plastic substrate.

[0156] (1st electrode 2) The first electrode 2 is conductive. In an organic EL device according to one embodiment of the present invention, the first electrode 2 is preferably a positive electrode. The first electrode 2 is preferably a pixel electrode. The first electrode 2 is preferably a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

[0157] The material constituting the first electrode 2 is not particularly limited, and examples thereof include metals, metal alloys, and conductive compounds. If the first electrode 2 is a transmissive electrode, the first electrode 2 preferably contains a transparent metal oxide such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), or ITZO (indium tin zinc oxide). If the first electrode 2 is a semi-transmissive electrode or a reflective electrode, the first electrode 2 preferably contains Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture thereof (e.g., a mixture of Ag and Mg).

[0158] The first electrode 2 may be a single layer made of a single material, a single layer made of multiple different materials, or a multilayer structure having multiple layers made of multiple different materials.

[0159] The thickness of the first electrode 2 is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 100 nm or more and 300 nm or less.

[0160] (Hole transport region 3) The hole transport region 3 is provided on the first electrode 2. The hole transport region 3 includes at least one of a hole injection layer 31, a hole transport layer 32, a hole buffer layer (not shown), and an electron blocking layer 33.

[0161] The hole transport region 3 may be a single layer made of a single material, a single layer made of multiple different materials, or a multi-layer structure having multiple layers made of multiple different materials.

[0162] For example, the hole transport region 3 may have a single layer structure of a hole injection layer 31 or a hole transport layer 32. Alternatively, for example, the hole transport region 3 may have a single layer structure formed of a hole injection material and a hole transport material. Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole transport layer 32, which are stacked in this order from the first electrode 2. Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole transport layer 32 / hole buffer layer (not shown). Alternatively, for example, the hole transport region 3 may have a structure of hole injection layer 31 / hole buffer layer (not shown), which are stacked in this order from the first electrode 2. Alternatively, for example, the hole transport region 3 may have a structure of hole transport layer 32 / hole buffer layer (not shown), which are stacked in this order from the first electrode 2. Furthermore, for example, the hole transport region 3 may have a structure of a hole injection layer 31 / a hole transport layer 32 / an electron blocking layer 33, which are stacked in this order from the first electrode 2. However, the structure of the hole transport region 3 is not limited to this.

[0163] The hole injection layer 31 and other layers constituting the hole transport region 3 are not particularly limited, and may contain, for example, a known hole injection material. Examples of hole injection materials include phthalocyanine compounds such as copper phthalocyanine, DNTPD (N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine), m-MTDATA (4,4',4"-tris(3-methylphenylphenylamino)triphenylamine), TDATA (4,4',4"-tris(N,N-diphenylamino)triphenylamine), 2-TNATA (4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine), PEDOT / PSS (poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate)), and PANI / DBSA (polyaniline). / dodecylbenzenesulfonic acid), PANI / CSA (polyaniline / camphorsulfonic acid), PANI / PSS (polyaniline) / poly(4-styrenesulfonate), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), triphenylamine-containing polyether ketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, HAT-CN (dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile), F6-TCNNQ (1,3,4,5,7,8-hexafluorotetracyano-2,6-naphthoquinodimethane), etc.

[0164] The hole transport layer 32 and other layers constituting the hole transport region 3 are not particularly limited, but may contain, for example, a known hole transport material. Examples of hole transport materials include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine) and TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), NPB (N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine), TAPC (4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine]), HMTPD (4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl), mCP (1,3-bis(N-carbazolyl)benzene), Compound H1 shown below, Compound H2 shown below, and Compound HT3 shown below.

[0165] [ka]

[0166] In addition to the hole injection material and hole transport material described above, the hole transport region 3 may further contain a charge generation material to improve conductivity. The charge generation material is uniformly or non-uniformly dispersed in the hole transport region 3 or in each layer constituting the hole transport region 3. The charge generation material is not particularly limited, and examples thereof include known charge generation materials. Examples of the charge generation material include p-dopants. Examples of p-dopants include quinone derivatives such as TCNQ (tetracyanoquinodimethane) and F4-TCNQ (2,3,5,6-tetrafluorotetracyanoquinodimethane), metal oxides such as tungsten oxide and molybdenum oxide, and cyano group-containing compounds.

[0167] The hole buffer layer (not shown) increases light emission efficiency by compensating for the resonance distance depending on the wavelength of light emitted from the light-emitting layer 4. The material contained in the hole buffer layer (not shown) is not particularly limited, and for example, a material used in a known hole buffer layer (not shown) can be used. In addition, for example, a compound that can be contained in the hole transport region 3 as described above can be used.

[0168] The electron blocking layer 33 is a layer that serves to prevent electrons from being injected from the electron transport region 5 to the hole transport region 3. The material contained in the electron blocking layer 33 is not particularly limited, and any known material used for electron blocking layers 33 can be used. For example, the host material contained in the above-mentioned light-emitting layer can be used, and preferred examples include the above-mentioned compounds H-H1 and HT1, which are host materials.

[0169] The thickness of the hole transport region 3 is not particularly limited, but is preferably 1 nm to 1000 nm, more preferably 10 nm to 500 nm. Regarding the layers constituting the hole transport region 3, the thickness of the hole injection layer 31 is not particularly limited, but is preferably 3 nm to 100 nm. The thickness of the hole transport layer 32 is not particularly limited, but is preferably 3 nm to 200 nm, more preferably 3 nm to 100 nm. The thickness of the electron blocking layer 33 is not particularly limited, but is preferably 1 nm to 100 nm. The thickness of the hole buffer layer (not shown) is not particularly limited, as long as it functions as a hole buffer layer without interfering with the function of the organic electroluminescence device. When the thickness of the hole transport region 3, hole injection layer 31, hole transport layer 32, or electron blocking layer 33 satisfies the above range, better hole transport characteristics can be obtained while suppressing an increase in the actual driving voltage.

[0170] The method for forming the hole transport region 3 and each of the layers that constitute it is not particularly limited, but examples thereof include known film formation methods such as vacuum deposition, spin coating, LB method, inkjet printing, laser printing, and laser thermal transfer.

[0171] (Emitting layer 4) The light-emitting layer 4 is disposed on the hole transport region 3. Details of the light-emitting layer 4 are as described above.

[0172] (Electron transport area 5) The electron transport region 5 is disposed on the light-emitting layer 4. The electron transport region 5 includes at least one of an electron injection layer 51, an electron transport layer 52, and a hole blocking layer 53, although embodiments are not limited thereto.

[0173] The electron transport region 5 may be a single layer made of a single material, or a single layer made of multiple different materials. The electron transport region 5 may also have a multilayer structure having multiple layers made of multiple different materials. For example, the electron transport region 5 may have a single layer structure of an electron injection layer 51 or an electron transport layer 52. Alternatively, the electron transport region 5 may have a single layer structure made of an electron injection material and an electron transport material. Alternatively, the electron transport region 5 may have a structure of an electron transport layer 52 / electron injection layer 51, which are stacked in this order from the light-emitting layer 4. Alternatively, the electron transport region 5 may have a structure of a hole-blocking layer 53 / electron transport layer 52 / electron injection layer 51, which are stacked in this order from the light-emitting layer 4. However, the structure of the electron transport region 5 is not limited to these.

[0174] The electron injection layer 51 and other layers constituting the electron transport region 5 are not particularly limited and may contain, for example, a known electron injection material. Examples of electron injection materials include lanthanum group metals such as LiQ (lithium quinolate), Li2O, BaO, and Yb, and metal halides such as LiF, NaCl, CsF, and RbCl. The electron injection layer 51 is not particularly limited and may contain, for example, an electron transport material described below and an insulating organic metal salt. The organic metal salt is not particularly limited and may, for example, have an energy band gap of 4 eV or more. Examples of organic metal salts include metal acetates, metal benzoates, metal acetoacetates, metal acetylacetonates, and metal stearates.

[0175] The electron transport layer 52 and other layers constituting the electron transport region 5 are not particularly limited, and may contain, for example, a known electron transport material. Examples of electron transport materials include anthracene compounds, Alq3 (tris(8-hydroxyquinolinolato)aluminum), 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, 2-(4-(N-phenylbenzimidazolyl-1-yl)phenyl)-9,10-dinaphthylanthracene, TPBi (1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Bphen (4,7-diphenyl-1,10-phenanthroline), and the like. 0-phenanthroline), TAZ (3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole), NTAZ (4-(naphthalen-1-yl)-3,5-diphenyl-4H-1,2,4-triazole), tBu-PBD (2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole), BAlq (bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato)aluminum), Bebq2 (beryllium bis(benzoquinolin-10-olato)), ADN (9,10-di(naphthalen-2-yl)anthracene), LiQ (lithium quinolate), and the following compounds ET1 and H91.

[0176] [ka]

[0177] The hole-blocking layer 53 serves to prevent holes from being injected from the hole-transporting region 3 to the electron-transporting region 5. The material contained in the hole-blocking layer 53 is not particularly limited, and any known material used for hole-blocking layers 53 can be used. The hole-blocking layer 53 may contain, for example, a known hole-blocking material. Examples of hole-blocking materials include BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and BpHen (4,7-diphenyl-1,10-phenanthroline). Examples of hole-element materials include the host materials contained in the light-emitting layer described above, and preferred examples include the host materials H-E1 and HT2 described above.

[0178] The thickness of the electron transport region 5 is not particularly limited, but is preferably 0.1 nm to 210 nm. The thickness of the electron transport region 5 is more preferably 30 nm to 150 nm, and even more preferably 100 nm to 150 nm. Regarding the layers constituting the electron transport region 5, the thickness of the electron transport layer 52 is not particularly limited, but is preferably 10 nm to 100 nm, and more preferably 15 nm to 50 nm. The thickness of the hole blocking layer 53 is not particularly limited, but is preferably 10 nm to 100 nm, and more preferably 15 nm to 50 nm. The thickness of the electron injection layer 51 is not particularly limited, but is preferably 0.1 nm to 10 nm, and more preferably 0.3 nm to 9 nm. When the thickness of the electron injection layer 51 is within the above range, better electron injection characteristics can be obtained while substantially suppressing an increase in driving voltage. Furthermore, when the thickness of the electron transport region 5, the electron injection layer 51, the electron transport layer 52, or the hole blocking layer 53 is within the above range, a substantial increase in driving voltage can be suppressed while better electron transport properties can be obtained.

[0179] The method for forming the electron transport region 5 and each of the layers that constitute it is not particularly limited, but examples thereof include known film formation methods such as vacuum deposition, spin coating, LB method, inkjet printing, laser printing, and laser thermal transfer.

[0180] The second electrode 6 is disposed on the electron transport region 5. The second electrode 6 is conductive. In an organic EL device according to one embodiment of the present invention, the second electrode 6 is preferably a common electrode or a negative electrode. The second electrode 6 is preferably a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

[0181] The material constituting the second electrode 6 is not particularly limited, and examples thereof include metals, metal alloys, and conductive compounds. If the second electrode 6 is a transmissive electrode, the second electrode 6 preferably contains a transparent metal oxide such as ITO, IZO, ZnO, or ITZO. If the second electrode 6 is a semi-transmissive electrode or a reflective electrode, the second electrode 6 preferably contains Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF / Ca, LiF / Al, Mo, Ti, or a compound or mixture containing any of these (for example, a mixture of Ag and Mg).

[0182] The second electrode 6 may be a single layer made of a single material, a single layer made of multiple different materials, or a multi-layer structure having multiple layers made of multiple different materials.

[0183] The thickness of the second electrode 6 is not particularly limited, but is preferably 10 nm or more and 1000 nm or less.

[0184] The second electrode 6 may be connected to an auxiliary electrode (not shown). By connecting the second electrode 6 to the auxiliary electrode, the resistance of the second electrode 6 can be further reduced.

[0185] Furthermore, a capping layer (not shown) may be further disposed on the second electrode 6. The capping layer (not shown) is not particularly limited, and may be, for example, a layer containing α-NPD, NPB, TPD, m-MTDATA, Alq, CuPc, TPD15 (N,N,N',N'-tetra(biphenyl-4-yl)biphenyl-4,4'-diamine), TCTA (4,4',4"-tri-9-carbazolyltriphenylamine), N,N'-bis(naphthalen-1-yl), or the like.

[0186] The materials constituting the above-mentioned layers and electrodes may be used singly or in combination of two or more.

[0187] 1 to 3, the above-mentioned fused ring compound or the above-mentioned material for an organic electroluminescence device is preferably contained in the light-emitting layer 4, but may be contained in an organic layer other than the light-emitting layer 4. Furthermore, the above-mentioned fused ring compound or the above-mentioned material for an organic electroluminescence device may be contained in the light-emitting layer 4 and an organic layer other than the light-emitting layer 4.

[0188] 1 to 3, when a voltage is applied to each of the first electrode 2 and the second electrode 6, holes injected from the first electrode 2 move to the light-emitting layer 4 via the hole transport region 3, and electrons injected from the second electrode 6 move to the light-emitting layer 4 via the electron transport region 5. The electrons and holes recombine in the light-emitting layer 4 to generate excitons, which emit light as they fall from the excited state to the ground state.

[0189] The present invention encompasses the following aspects and configurations.

[0190] 1. Ar having a structure represented by the following general formula 1 1 or Ar 2 and wherein one structure represented by the following general formula 2 is added to a ring-forming atom of Ar of the structure represented by the general formula 2 5 and Ar6 A compound having a structure in which one to four structures represented by the following general formula 3 are added to at least one of the ring-forming atoms of the compound:

[0191] [ka]

[0192] In the general formula 1, the general formula 2 and the general formula 3, Ar 1 ~Ar 8 are each independently a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, In the general formula 2, X is —O—, —S—, —NR 21 -or-CR 22 R 23 - and R 21 , R 22 and R 23 are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and X is -NR 21 -If R 21 Via Ar 7 and In the general formula 1, Z is carbon or silicon, In the general formula 2, the two bonds *1 are Ar 1 or two bonds *1 are bonded to the two ring-forming atoms of Ar 2 and bonded to the two ring-forming atoms of In the general formula 3, Y is —O—, —S—, or —NR 31 - and R 31 is hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and the two bonds *2 are Ar 5or two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 2 6 It bonds to two ring-forming atoms.

[0193] 2. Ar having the structure represented by the general formula 1 1 or Ar 2 and wherein one structure represented by the following general formula 4 is added to a ring-forming atom of Ar having a structure represented by the following general formula 4 5’ and Ar 6 The compound according to the above item 1, having a structure in which one to four structures represented by the following general formula 5 are added to at least one of the ring-forming atoms:

[0194] [ka]

[0195] In the general formula 4, R 41 is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; n is 0, 1, 2, or 3, where when n is 2 or more, R 41 may be the same or different, Ar 6 , Ar 7 , X and the bond *1 are defined as in the general formula 2 above, In the general formula 5, Ar 9 is a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, The two bonds *2 are Ar in the structure represented by the general formula 5. 5’ or two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 5. 6 and bonded to the two ring-forming atoms of Ar 8has the same meaning as that explained in the general formula 3 above.

[0196] 3. Ar having the structure represented by the general formula 1 1 or Ar 2 The compound according to 1. or 2. above, having a structure in which one structure represented by the following general formula 6 is added to a ring-forming atom of the compound:

[0197] [ka]

[0198] In the general formula 6, R 61 is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; m is 0 or 1, Ar 6 , Ar 7 , X and the bond *1 are defined as in the general formula 2, and Ar 8 is the same as defined in the general formula 3, and Ar 9 has the same meaning as that explained in the general formula 5 above.

[0199] 4. Ar having the structure represented by the general formula 1 1 or Ar 2 The compound according to 1. or 2. above, having a structure in which one structure represented by the following general formula 7 is added to a ring-forming atom of the compound:

[0200] [ka]

[0201] In the general formula 7, R 71 and R 72 are each independently deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; o is 0, 1, 2, 3 or 4, where when o is 2 or more, R 71 may be the same or different, p is 0, 1, 2, or 3, where, when p is 2 or more, R 72 may be the same or different, X and the bond *1 are defined as in the general formula 2, and Ar 8 is the same as defined in the general formula 3, and Ar 9 is the same as defined in the general formula 5, and R 61 and m have the same meanings as those in the general formula 6.

[0202] 5. A composition comprising the compound described in any one of 1. to 4. above.

[0203] 6. The composition according to 5 above, further comprising at least one of a thermally activated delayed fluorescent material and a phosphorescent material.

[0204] 7. The composition according to claim 6, wherein the phosphorescent material is a platinum complex.

[0205] 8. A material for an organic electroluminescence device, comprising the compound according to any one of 1. to 4. above.

[0206] 9. An organic electroluminescence device having an organic layer containing the compound according to any one of 1. to 4. above.

[0207] 10. The organic electroluminescence device according to the above item 9, wherein the organic layer is a light-emitting layer. [Example]

[0208] The present invention will be described in more detail using the following examples and comparative examples, but the technical scope of the present invention is not limited to the following examples.

[0209] [Synthesis of Compound 1]

[0210] [ka]

[0211] <Synthesis of Intermediate 1> A reaction vessel was charged with 3.6 g (10.83 mmol, 1.0 equiv.) of 2-hydroxy-9,9'-spirobi[9H-fluorene], 2.7 g (14.08 mmol, 1.3 equiv.) of 1-bromo-2,6-difluorobenzene, 1.5 g (10.83 mmol, 1.0 equiv.) of potassium carbonate, and 20 ml of 1-methyl-2-pyrrolidone, and the mixture was refluxed under a nitrogen atmosphere for 8 hours with stirring. After the reaction was complete, the mixture was diluted with toluene and filtered through Celite. The filtrate was concentrated and dispersed and washed with methanol to obtain intermediate 1 (3.9 g, 72% yield).

[0212] <Synthesis of intermediate 2> A reaction vessel was charged with 3.94 g (7.79 mmol, 1.05 equivalents) of intermediate 1, 3.3 g (7.42 mmol, 1.0 equivalents) of 12-(3,5-di-tert-butylphenyl)-5,12-dihydroindolo[3,2-a]carbazole, 3.63 g (11.1 mmol, 1.5 equivalents) of cesium carbonate, and 8 ml of dimethyl sulfoxide, and the mixture was heated and stirred at 160°C for 24 hours under a nitrogen atmosphere. After the reaction was complete, the mixture was diluted with toluene and filtered through Celite. Water was added to the filtrate, and the organic layer was dried over magnesium sulfate and concentrated. The mixture was then purified by column chromatography to obtain intermediate 2 (yield 3.0 g, 43%).

[0213] <Synthesis of Compound 1> A reaction vessel was charged with 3.0 g (3.23 mmol, 1.0 equivalent) of intermediate 2 and 16 ml of tert-butylbenzene and stirred. The mixture was cooled to -50°C under a nitrogen atmosphere, and 1.8 ml (4.8 mmol, 1.5 equivalents) of a 2.6 M n-butyllithium hexane solution was added dropwise. The mixture was then stirred for 1 hour. 0.89 g (3.55 mmol, 1.1 equivalents) of boron tribromide was then added and stirred at 0°C for 1 hour. 0.84 g (2.0 equivalents, 6.45 mmol) of N,N-diisopropylethylamine was then added and heated and stirred at 150°C for 12 hours. After completion of the reaction, the reaction solution was cooled to room temperature, and the organic layer was extracted with water and dichloromethane. The organic layer was dried over magnesium sulfate, concentrated, and purified by silica gel column chromatography to obtain compound 1 (yield: 0.77 g, 27%).

[0214] <Confirmation of the structure of compound 1> The structure of Compound 1 was confirmed using liquid chromatography mass spectrometry (LC / MS). Specifically, the sample (obtained Compound 1) was dissolved in tetrahydrofuran at a concentration of 0.1% by mass, and then mass spectrometry was performed using an LC / MS measuring system 1260 Infinity-Quadrupole 6100MS (manufactured by Agilent Technologies). The results obtained are shown below: LC-MS: 859 ([M+H] + ).

[0215] [Synthesis of Compound 2]

[0216] [ka]

[0217] <Synthesis of intermediate 3> Intermediate 3 was synthesized in the same manner as in <Synthesis of Intermediate 1>, except that 1-bromo-2,6-difluorobenzene in <Synthesis of Intermediate 1> was changed to 4'-bromo-3',5'-difluoro-3,5-ditertbutyl-1,1'-biphenyl (yield 10.5 g, 59%).

[0218] <Synthesis of intermediate 4> Intermediate 4 was synthesized in the same manner as in <Synthesis of Intermediate 2> except that Intermediate 1 in <Synthesis of Intermediate 2> was changed to Intermediate 3 (yield: 6.8 g, 42%).

[0219] <Synthesis of Compound 2> Compound 2 was synthesized in the same manner as in the synthesis of compound 1, except that intermediate 2 in <Synthesis of compound 1> was changed to intermediate 4 (yield: 0.8 g, 12%).

[0220] <Confirmation of the structure of compound 2> The structure of Compound 2 was confirmed in the same manner as Compound 1: LC-MS: 1048 ([M+H] + ).

[0221] [Synthesis of Compound 3]

[0222] [ka]

[0223] <Synthesis of intermediate 5> Intermediate 5 was synthesized in the same manner as in <Synthesis of Intermediate 3>, except that 2-hydroxy-9,9'-spirobi[9H-fluorene] in <Synthesis of Intermediate 1> was changed to 1-hydroxy-9,9'-spirobi[9H-fluorene] and 1-bromo-2,6-difluorobenzene was changed to 4'-bromo-3',5'-difluoro-3,5-ditertbutyl-1,1'-biphenyl (yield 9.5 g, 54%).

[0224] <Synthesis of intermediate 6> Intermediate 6 was synthesized in the same manner as in <Synthesis of Intermediate 2> except that Intermediate 1 in <Synthesis of Intermediate 2> was changed to Intermediate 5 (yield: 7.8 g, 50%).

[0225] <Synthesis of Compound 3> Compound 3 was synthesized in the same manner as in <Synthesis of Compound 1> except that intermediate 2 in <Synthesis of Compound 1> was changed to intermediate 6 (yield: 1.0 g, 20%).

[0226] <Confirmation of the structure of compound 3> The structure of compound 3 was confirmed in the same manner as for compound 1: LC-MS: 1048 ([M+H] + ).

[0227] [Synthesis of Compound 4]

[0228] [ka]

[0229] <Synthesis of intermediate 7> A reaction vessel was charged with 15.0 g (29.7 mmol, 1.0 equivalent) of intermediate 1, 9.1 g (35.6 mmol, 1.2 equivalents) of 5,12-dihydroindolo[3,2-a]carbazole, 14.5 g (44.5 mmol, 1.5 equivalents) of cesium carbonate, and 30 ml of dimethyl sulfoxide. The mixture was heated and stirred at 160°C for 30 hours under a nitrogen atmosphere. After the reaction was complete, the mixture was diluted with toluene and filtered through Celite. Water was added to the filtrate to extract the organic layer, which was then dried over magnesium sulfate and concentrated. The mixture was then purified by silica gel column chromatography to obtain intermediate 7 (yield 10.0 g, 45%).

[0230] <Synthesis of intermediate 8> A reaction vessel was charged with 5.0 g (6.7 mmol, 1.0 equiv.) of intermediate 7, 3.4 g (8.8 mmol, 1.3 equiv.) of 3,5-di-tert-butyl-4'-iodo-1,1'-biphenyl, 2.8 g (20.2 mmol, 3.0 equiv.) of potassium carbonate, 0.214 mg (3.37 mmol, 0.5 equiv.) of copper powder, and 7 ml of o-dichlorobenzene, and the mixture was refluxed under a nitrogen atmosphere for 24 hours with stirring. After the reaction was complete, the mixture was diluted with toluene and filtered through Celite. The filtrate was concentrated and purified by silica gel column chromatography to obtain intermediate 8 (6.2 g, 92% yield).

[0231] <Synthesis of Compound 4> 2.0 g (3.28 mmol, 1.0 equivalent) of intermediate 8 and 2.5 ml of tert-butylbenzene were added to a reaction vessel and stirred. Under a nitrogen atmosphere, the reaction solution was cooled to -50°C, and 0.7 ml (1.1 mmol, 2.2 equivalents) of a 1.6 M tert-butyllithium pentane solution was added dropwise. The mixture was stirred at room temperature (25°C) for 1 hour, after which low-boiling components were distilled off. The mixture was then cooled to 0°C, and 0.05 ml (0.6 mmol, 1.1 equivalents) of boron tribromide was added. The mixture was stirred at room temperature (25°C) for 1 hour. 0.17 ml (1.0 mmol, 2.0 equivalents) of N,N-diisopropylethylamine was then added, and the mixture was heated and stirred at 150°C for 20 hours. After the reaction was complete, the reaction solution was cooled to room temperature, and the organic layer was extracted with water and toluene. The organic layer was dried over magnesium sulfate and concentrated. Thereafter, the mixture was purified by silica gel column chromatography to obtain Compound 4 (yield: 0.13 g, 28%).

[0232] <Confirmation of the structure of compound 4> The structure of compound 4 was confirmed in the same manner as for compound 1: LC-MS: 936 ([M+H] + ).

[0233] <Simulation evaluation of fused ring compounds> In “High-Performance Dibenzoheteraborin-Based Thermally Activated Delayed Fluorescence Emitters: Molecular Architectonics for Concurrently Achieving Narrowband Emission and Efficient Triplet-Singlet Spin Conversion” by Seob Park, Kyohei Matsuo, Naoya Aizawa, and Takuma Yasuda, Advanced Functional Materials 2018, 28, 1802031, it was shown that the spectral width of fluorescence emission (full width at half maximum, FWHM) is closely related to the reorganization energy [E(S0@S1)-E(S0@S0)], which is expressed as the difference between the energy of the ground state (S0) in the stable structure of the first excited singlet state (S1) [E(S0@S1)] and the energy of the ground state (S0) in the stable structure of the ground state (S0) [E(S0@S0)].

[0234] [Calculation of oscillator strength (f), rearrangement energy, and fluorescence wavelength of the compound of the present invention and comparative compound R1] The compounds of the present invention and the following known inter-fused compound R1 (comparative compound 1) were subjected to the following calculations by density functional theory (DFT), and the oscillator strength (f), rearrangement energy, and fluorescence wavelength of compounds 1 to 3 of the present invention and comparative compound 1 were calculated.

[0235] [ka]

[0236] The ground state (S0) energy in the stable structure of the first excited singlet state (S1) [E(S0@S1)] and the ground state (S0) energy in the stable structure of the ground state (S0) [E(S0@S0)] were calculated, and the rearrangement energy [E(S0@S1)]-[E(S0@S0)] (eV) was calculated from the difference between these.

[0237] In addition, the energy of the first excited singlet state (S1) in the stable structure of the first excited singlet state (S1) [E(S1@S1)] was calculated, and the adiabatic first excited singlet state (S1) energy [E(S1@S1)]-[E(S0@S0)] (eV) was calculated from the difference between this value and the energy of the ground state (S0) in the stable structure of the ground state (S0) [E(S0@S0)].

[0238] The adiabatic first excited singlet state (S1) energy (eV) was converted into the light wavelength (nm) to calculate the fluorescence wavelength (nm).

[0239] Furthermore, the oscillator strength f in the stable structure of the first excited singlet state (S1) was calculated.

[0240] Here, calculations by density functional theory (DFT) were performed using Gaussian 16 (Gaussian Inc.) as calculation software, using the following calculation methods (I), (II), and (III): (I) S0 calculation method: structural optimization calculation using functional B3LYP, basis set 6-31G(d,p), and DFT including toluene solvent effect (PCM); (II) S1 calculation method: Geometry optimization calculation using functional B3LYP, basis set 6-31G(d,p), and time-dependent DFT (TDDFT) including toluene solvent effect (PCM); (III) S0 calculation method: Calculation using the input structure by DFT including the functional B3LYP, basis set 6-31G(d,p), and toluene solvent effect (PCM).

[0241] More specifically, the calculations for each item were carried out using the following calculation methods: Energy of the ground state (S0) in the stable structure of the ground state (S0) [E(S0@S0)]: calculation method (I) above; Energy of the first excited singlet state (S1) in the stable structure of the first excited singlet state (S1) [E(S1@S1)]: calculation method (II) above; Ground state (S0) energy in the stable structure of the first excited singlet state (S1) [E(S0@S1)]: calculation methods (II) and (III) above; Rearrangement energy [E(S0@S1)]-[E(S0@S0)]: calculation methods (I), (II), and (III); Adiabatic first excited singlet state (S1) energy [E(S1@S1)]-[E(S0@S0)]: calculation methods (I) and (II) above; Fluorescence wavelength (nm): calculation method (I) and (II) above; · Oscillator strength f in the stable structure of the first excited singlet state (S1): Calculation method (II) above.

[0242] FIG. 4 is an explanatory diagram qualitatively explaining the relationship between the energies.

[0243] The results of the above calculations are shown in Table 1.

[0244] [Table 1-1]

[0245] [Table 1-2]

[0246] [Table 1-3]

[0247] As shown in Table 1 above, the fused ring compounds of the present invention have a maximum reorganization energy of 0.11 eV, which is the same value as Comparative Compound 1, and most of the fused ring compounds of the present invention have smaller reorganization energy values than Comparative Compound 1. From this, it is presumed that the FWHM of the fused ring compounds of the present invention will be equal to or smaller than the FWHM of the known Comparative Compound 1, and that the color purity will also be equal to or higher than that of the known Comparative Compound 1.

[0248] Furthermore, it was confirmed that the fused ring compound of the present invention has a sufficiently large oscillator strength f and is excellent in fluorescence emission efficiency.

[0249] From the above results, it was found that the compounds of the present invention have smaller rearrangement energies, larger oscillator strengths f, and suitable blue fluorescence wavelengths compared to the comparative compounds. This confirms that the compounds of the present invention have narrow emission spectrum widths and can achieve high color purity, and are therefore promising as blue-emitting materials that can improve the luminous efficiency of organic EL devices.

[0250] <Compound evaluation> [Method of preparing thin films] On a quartz substrate, Compounds 1 to 3 or Comparative Compound 1 were applied in a weight ratio of 1 mass % relative to the host compound. -5 A 50 nm-thick thin film (hereinafter also referred to as "host-dispersed film") was prepared by co-evaporation at a vacuum of 100 Pa. Here, compound HT1, compound HT2, and phosphorescent complex Pt1 were used as host compounds, and the mass ratio of compound HT1:compound HT2:phosphorescent complex Pt1 was 60:40:13. The structures of HT1, HT2, and phosphorescent complex Pt1 are shown below.

[0251] [ka]

[0252] [Photoluminescence (PL) measurement (FWHM)] The thin film (host-dispersed film) prepared above was cut into 6 mm wide strips and PL measurements were performed at room temperature using a Hitachi High-Technologies F-7000 spectrofluorometer. From the obtained emission spectrum, the peak wavelength (maximum emission wavelength) and the wavelength width at which the emission intensity is reduced to half (FWHM) were calculated. These evaluation results are shown in Table 2 below.

[0253] [PLQY measurement] The PLQY of the thin film (host-dispersed film) prepared above was measured using a Quantaurus-QY absolute PL quantum yield (PLQY) measurement system C11347-01 manufactured by Hamamatsu Photonics K.K. During the measurement, the excitation wavelength was scanned from 280 nm to 350 nm at 10 nm intervals, and the excitation wavelength range in which the compound's absorption value showed an excitation light intensity ratio of 20% or more was used. The PLQY value was taken as the highest value within the excitation wavelength range used. These evaluation results are shown in Table 2 below.

[0254] [Table 2]

[0255] From the results in Table 2 above, it was confirmed that Compounds 1 to 3 of the present invention emit light with a narrow spectral width and a peak wavelength in the blue wavelength range, and that they emit blue light with high color purity. It was also found that Compounds 1 to 3 of the present invention have a higher PLQY than Comparative Compound 1.

[0256] [Fabrication of organic electroluminescence elements (organic electroluminescence elements, organic EL elements)] <Fabrication of organic EL elements> (Element fabrication example 1) The ITO glass substrate with the electrode pattern formed was cut into a size of 50 mm x 50 mm x 0.7 mm, and ultrasonically cleaned in acetone, isopropyl alcohol, and pure water, in that order, for 15 minutes each, followed by UV ozone cleaning for 30 minutes.The following layers were deposited on the ITO electrode (anode) on this glass substrate using a vacuum deposition system.

[0257] First, HAT-CN (see chemical formula below) was vapor-deposited on the ITO electrode to form a hole injection layer with a thickness of 10 nm. Next, compound HT3 (see chemical formula below) was vapor-deposited on the hole injection layer to form a hole transport layer with a thickness of 140 nm. Next, compound HT1 (see chemical formula below) was vapor-deposited on the hole transport layer to form an electron blocking layer with a thickness of 5 nm. In this way, a hole transport region was formed.

[0258] On the hole transport region formed above, compound HT1, compound HT2, phosphorescent complex Pt1 (see chemical formula below), and compound 1 obtained above were co-deposited to form an emitting layer with a thickness of 40 nm. The emitting layer was formed so that the mass ratio of compound HT1, compound HT2, and phosphorescent complex Pt1 in the emitting layer was compound HT1:compound HT2:phosphorescent complex Pt1=60:40:13. The emitting layer was formed so that the concentration of compound 1 in the emitting layer was 1.0 mass% relative to the total mass of compound HT1, compound HT2, phosphorescent complex Pt1, and compound 1 (i.e., the total mass of the emitting layer). Compounds HT1 and HT2 are host materials.

[0259] Compound HT2 was vacuum-deposited on the light-emitting layer obtained above to form a hole-blocking layer with a thickness of 5 nm. Compound H91 and LiQ were then co-deposited on the hole-blocking layer in a mass ratio of Compound H91:LiQ = 5:5 (unit: parts by mass) to form an electron-transporting layer with a thickness of 30 nm. LiQ was then vapor-deposited on the electron-transporting layer to form an electron-injecting layer with a thickness of 1 nm. Thus, an electron-transporting region was formed.

[0260] On the electron injection layer formed above, Al (cathode) was deposited to a thickness of 100 nm by vapor deposition, thereby producing Organic EL Device 1.

[0261] Thereafter, in a nitrogen atmosphere glove box with a moisture concentration of 1 ppm or less and an oxygen concentration of 1 ppm or less, the organic EL element 1 prepared above was sealed using a glass sealing tube with a desiccant and an ultraviolet curable resin (manufactured by MORESCO Corporation, product name WB90US). In this way, the organic EL element 1 was completed.

[0262] [ka]

[0263] (Element fabrication example 2) Organic EL element 2 was produced in the same manner as in element production example 1, except that compound 1 in the light-emitting layer was changed to compound 2 in the film formation of the light-emitting layer, and then sealed to complete organic EL element 2.

[0264] (Element fabrication example 3) Organic EL element 3 was produced in the same manner as in element production example 1, except that compound 1 in the light-emitting layer was changed to compound 3 in the film formation of the light-emitting layer, and then sealed to complete organic EL element 3.

[0265] (Comparative element preparation example 1) Comparative organic EL element 1 was produced in the same manner as in element production example 1, except that in the formation of the light-emitting layer, compound 1 in the light-emitting layer was changed to comparative compound 1, and then sealed to complete comparative organic EL element 1.

[0266] <Evaluation of organic EL elements> [Brightness, external quantum efficiency and device lifespan] According to the following method, brightness is 1,000 cd / m 2 The emission peak wavelength, emission spectrum width, external quantum efficiency, and device lifetime were evaluated.

[0267] Using a DC constant voltage power supply (Keithley Instruments, Source Meter Model 2400), the organic EL element was made to emit light while changing the applied voltage, and the luminance, emission spectrum, and amount of light emitted were measured using a luminance measuring device (Topcon, SR-3).

[0268] The external quantum yield was calculated from the emission spectrum, luminance, and current value at the time of measurement. 2 The external quantum yield at the saturation temperature was defined as EQE [%].

[0269] In addition, the element life (durability) is 1,000 cd / m 2 The device was continuously driven at a current value of 1000 V, and the time it took for the luminance to decay over time to reach 95% of its initial luminance was defined as LT95. In Table 3 below, LT95 is shown as a relative value, with the LT95 (unit: hr) of Comparative Organic EL Device 1 being set to 1.

[0270] [Emission peak wavelength and emission spectral width (FWHM, FWQM)] The emission peak wavelength and emission spectrum width were determined from the emission spectrum measurement results. The wavelength showing the maximum value of the emission spectrum was defined as the emission peak wavelength, the wavelength width corresponding to half of the maximum value as the full width at half maximum (FWHM), and the wavelength width corresponding to one-quarter of the maximum value as the full width at half maximum (FWQM).

[0271] In this evaluation, the peak wavelength of the light emission is not particularly limited, but is preferably within the blue light emission region, more preferably 455 nm or more and 475 nm or less, and even more preferably 455 nm or more and 465 nm or less.

[0272] In this evaluation, the smaller the spectral widths FWHM and FWQM of the light emission, the more preferable it is, and it is judged that the higher the color purity is.

[0273] The evaluation results of the organic EL devices are shown in Table 3 below.

[0274] [Table 3]

[0275] As is clear from the results in Table 3 above, organic EL devices 1 to 3 using compounds 1 to 3 of the present invention have smaller FWHM and FWQM, narrower spectral widths, and emit blue light with high color purity, compared to comparative organic EL device 1 using comparative compound 1. Furthermore, compounds 1 to 3 of the present invention exhibit high external quantum efficiency (EQE), and therefore organic EL devices 1 and 2 using these compounds are superior in luminous efficiency and also in device lifetime. In particular, organic EL device 2 using compound 2 of the present invention exhibited a 1.3-fold improvement in EQE and a 4-fold improvement in lifetime compared to comparative organic EL device 1 using comparative compound 1.

[0276] By using the compound of the present invention as a light-emitting material, it is possible to obtain a blue electroluminescent device with an emission wavelength of 465 nm or less, which has a narrower spectral width, higher efficiency and a longer life than conventional light-emitting materials.

[0277] The present invention has been described above with reference to embodiments and examples, but the present invention is not limited to the specific embodiments and examples, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of symbols]

[0278] 1 board, 2 first electrode, 3 hole transport region, 4 emitting layer, 5 Electron transport area, 6 second electrode, 10 Organic electroluminescent element (organic EL element), 31 hole injection layer, 32 hole transport layer, 33 electron blocking layer, 51 electron injection layer, 52 electron transport layer, 53 Hole blocking layer.

Claims

1. Ar having a structure represented by the following general formula 1 １ or Ar ２ and wherein one structure represented by the following general formula 2 is added to a ring-forming atom of Ar of the structure represented by the general formula 2 ５ and Ar ６ A compound having a structure in which one to four structures represented by the following general formula 3 are added to at least one of the ring-forming atoms of the compound: 【Chemical 1】 In the general formula 1, the general formula 2 and the general formula 3, Ar １ ~Ar ８ are each independently a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, In the general formula 2, X is —O—, —S—, or —NR ２１ -or-CR ２２ R ２３ - and R ２１ , R ２２ and R ２３ are each independently hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and X is —NR ２１ -, then R ２１ via Ar ７ and In the general formula 1, Z is carbon or silicon, In the general formula 2, the two bonds *1 are Ar in the structure represented by the general formula 1. １ or the two bonds *1 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 1. ２ and bonded to two ring-forming atoms of In the general formula 3, Y is —O—, —S—, or —NR ３１ - and R ３１ is hydrogen, deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group, and the two bonds *2 are Ar in the structure represented by the general formula 2. ５ or the two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 2. ６ is bonded to two ring-forming atoms of

2. Ar of the structure represented by the general formula 1 １ or Ar ２ and wherein one structure represented by the following general formula 4 is added to a ring-forming atom of Ar having a structure represented by the following general formula 4 ５’ and Ar ６ The compound according to claim 1, having a structure in which one to four structures represented by the following general formula 5 are added to at least one of the ring-forming atoms of the compound: 【Chemistry 2】 In the general formula 4, R ４１ is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; n is 0, 1, 2, or 3, where when n is 2 or more, R ４１ may be the same or different, Ar ６ , Ar ７ , X and the bond *1 are the same as those described in the general formula 2 above, In the general formula 5, Ar ９ is a substituted or unsubstituted aromatic hydrocarbon ring having from 6 to 30 ring atoms, or a substituted or unsubstituted aromatic heterocycle having from 5 to 30 ring atoms, The two bonds *2 are Ar in the structure represented by the general formula 5. ５’ or the two bonds *2 are bonded to the two ring-forming atoms of Ar in the structure represented by the general formula 5. ６ and bonded to two ring-forming atoms of Ar ８ has the same meaning as that explained in the general formula 3 above.

3. Ar of the structure represented by the general formula 1 １ or Ar ２ The compound according to claim 1 or 2, having a structure in which one structure represented by the following general formula 6 is added to a ring-forming atom of 【Chemistry 3】 In the general formula 6, R ６１ is deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; m is 0 or 1; Ar ６ , Ar ７ , X and the bond *1 are the same as those in the general formula 2, and Ar ８ has the same meaning as in the general formula 3, and Ar ９ has the same meaning as that explained in the general formula 5 above.

4. Ar of the structure represented by the general formula 1 １ or Ar ２ The compound according to claim 1 or 2, having a structure in which one structure represented by the following general formula 7 is added to a ring-forming atom of 【Chemistry 4】 In the general formula 7, R ７１ and R ７２ are each independently deuterium, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group; o is 0, 1, 2, 3, or 4, where when o is 2 or more, R ７１ may be the same or different, p is 0, 1, 2, or 3, where, when p is 2 or more, R ７２ may be the same or different, X and the bond *1 are the same as those in the general formula 2, and Ar ８ has the same meaning as in the general formula 3, and Ar ９ is the same as that described in the general formula 5, and R ６１ and m have the same meanings as those in the general formula 6.

5. A composition comprising a compound according to claim 1 or 2.

6. The composition according to claim 5 , further comprising at least one of a thermally activated delayed fluorescent material and a phosphorescent material.

7. The composition of claim 6 , wherein the phosphorescent material is a platinum complex.

8. A material for an organic electroluminescence device, comprising the compound according to claim 1 or 2.

9. An organic electroluminescence device having an organic layer containing the compound according to claim 1 or 2.

10. The organic electroluminescence device according to claim 9 , wherein the organic layer is a light-emitting layer.

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