Organic electroluminescence device, thin film, compound, delayed fluorescence emitter, and organic semiconductor laser

Abstract

The organic electroluminescence device of the disclosure includes a compound represented by the following general formula

Description

[Technical Field]

[0001] This invention relates to an organic electroluminescent element, a thin film, a compound, a delayed phosphor, and an organic semiconductor laser. [Previous Technology]

[0002] Significant progress has been made in organic light-emitting diodes (OLEDs) in the visible spectrum region. In recent years, there has been increased interest in OLEDs that emit light in the near-infrared (NIR) region (i.e., 700 nm to 2500 nm). The potential applications of these NIR OLEDs are attracting considerable attention in bioimaging, medical cameras, sensors, surveillance cameras, night vision displays, and information protection displays. High-efficiency NIR emitters are required for the use of OLEDs.

[0003] Furthermore, in research related to organic electroluminescent devices, measures are being actively implemented to realize organic semiconductor laser devices. In particular, to realize such organic semiconductor laser devices, it is necessary to develop compounds that emit amplified spontaneous emission (ASE). Therefore, it has been reported that compounds useful as laser materials have been discovered through investigation of the ASE properties of various compounds (see Patent Documents 1-2, Non-Patent Documents 1-4). As a method for obtaining laser materials with a lower ASE threshold in the NIR region, a method using a curcuminoid compound has been reported (Patent Document 3). [Prior Art Documents] [Patent Documents]

[0004] Patent Document 1: Japanese Patent No. 5105820 Patent Document 2: International Publication No. 2020 / 175624 Patent Document 3: International Publication No. 2018 / 155724 Non-Patent Document 1: Kim, J.-H.; Inoue, M.; Zhao, L.; Komino, T.; Seo, S.; Ribierre, J.-C.; Adachi, C. Appl. Phys. Lett. 2015, 106, 053302. Non-Patent Literature 2: Spehr, T.; Siebert, A.; Fuhrmann, T.; Salbeck, J. "Org. Electron" (2003, 4, 61). Non-Patent Literature 3: Varghese, S.; Yoon, S.-J.; Calzado, EM; Casado, S.; Boj, PG; Diaz-Garcia, MA; Resel, R.; Fischer, R.; Milian-Medina, B.; Wannemacher, R.; Park, SY; Gierschner, J. "Advanced Materials" (2012, 24, 6473).Non-Patent Document 4: Sandanayaka, ASD; Matsushima, T.; Bencheikh, F.; Terakawa, S.; Potscavage, JWJ; Qin, C.; Fujihara, T.; Goushi, K.; Ribierre, J.-C.; Adachi, C. Appl. Phys. Express 2019, 12, 061010. [Summary of the Invention]

[0005] [The problem the invention aims to solve]

[0006] However, the compound described in Patent Document 3 cannot adequately satisfy the luminescence characteristics of NIR light emitters used in organic electroluminescent devices, nor can it achieve a low ASE threshold for NIR light emitters used in organic semiconductor lasers. [Means for Solving the Problem]

[0007] The present invention has been made in view of the above circumstances, and provides a compound, thin film, delayed fluorescence emitter, and organic electroluminescent element for an organic semiconductor laser that can achieve excellent light-emitting characteristics and excellent reduction of the ASE threshold of the NIR emitter. That is, the present invention can be as follows.

[0008] [1] An organic electroluminescent element containing a compound represented by general formula (1), [Chemical 1] (in general formula (1), X1 and X2 independently represent halogen atoms, alkyl halides or aryl halides, at least one of X1 and X2 represents alkyl halides or aryl halides; R1 to R6 independently represent hydrogen atoms or substituents, R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6, R6 and R7 can together represent a ring; R7 represents a group represented by general formula (2) or general formula (3) below; [Chemical 2] (in general formula (2), Ar1 represents aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl, R8 represents a substituent; multiple R 8 can be the same or different, at least one R 8 is an electron-donating group; n8 represents an integer from 1 to Ar 1 that can be substituted) [Chemical 3] (In general formula (3), R 9 to R 13 independently represent hydrogen atoms or substituents, and p represents an integer of 0 or 1 to 2)). [2] The organic electroluminescent element as described in [1], wherein the compound represented by the general formula (1) is the compound represented by the following general formula (4), [Chemical 4] (in general formula (4), X1, X2, and R2 to R6 have the same meaning as general formula (1); Ar2 and Ar3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl; R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring; R14 and R15 independently represent substituents, and multiple R14s can be the same or different, at least one R14 is an electron-donating group, and multiple R15s can be the same or different, at least one R15 is an electron-donating group; n14 represents 1 to Ar [2] The integer up to the number that can be substituted in 2, where n15 represents the integer up to the number that can be substituted in 1 to Ar3). [3] An organic electroluminescent element as described in [2], wherein in the general formula (4), at least one of R14 and R15 is a substituted or unsubstituted diarylamine group. [4] An organic electroluminescent element as described in [2] or [3], wherein in the general formula (4), Ar2 and Ar3 independently comprise a benzene structure, a naphthalene structure, an anthracene structure or a fusiform structure.[5] An organic electroluminescent element as described in any one of [1] to [4], wherein the compound represented by the general formula (1) is the compound represented by the following general formula (5), [Chemical 5] (in general formula (5), X1, X2, and R2 to R6 have the same meaning as the general formula (1); Ar4 to Ar7 each independently represent substituted or unsubstituted aryl groups, and each Ar4 and each Ar5 may be the same or different, and each Ar6 and each Ar7 may be the same or different; R16 and R17 each independently represent substituents other than substituted or unsubstituted diarylamine groups, and each R16 and R17 may be the same or different; R16 and R2, R3 and R4, R4 and R5, R6 and R17 may form a ring together; n16 and n18 each independently represent an integer greater than or equal to 0 or 1, n17 and n19 each independently represent an integer greater than or equal to 1, n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5. [6] An organic electroluminescent element as described in any one of [1] to [5], wherein R4 is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryloxycarbonyl group, a halogen atom, or a group containing a boron diketone ring. [7] An organic electroluminescent element as described in any one of [1] to [6], wherein R3 and R4, or R4 and R5 together form a ring.[8] The organic electroluminescent element as described in [1], wherein the compound represented by the general formula (1) is the compound represented by the following general formula (6), [Chemical 6] (in general formula (6), X1, X2, and R2 to R6 have the same meaning as general formula (1); X1' and X2' represent halogen atoms, alkyl halides or aryl halides, at least one of X1' and X2' represents alkyl halides or aryl halides; R2' to R6' each independently represent hydrogen atoms or substituents; R18 and R19 each independently represent one of the following group A, R18 and R2, R3 and R4, R4 and R5, R19 and R2', R3' and R4', and R4' and R5' can form a ring together, R6 can bond with A to form a ring, and R6' can bond with A to form a ring; A represents the linking group represented by the following general formula (7) or general formula (9); [Chemical 7] (in general formula (7), n is an integer from 0 to 1 to 4, m is 0 or 1, A' represents an alkoxy group having 1 to 12 carbon atoms, A'' represents the group represented by the following formula (8); [Chemical 8] (in general formula (8), X 1'' and X 2'' represent a halogen atom, a halogenated alkyl group or a halogenated aryl group, at least one of X 1'' and X 2'' represents a halogenated alkyl group or a halogenated aryl group, R 2'' to R 6'' each independently represent a hydrogen atom or a substituent, and R 20 represents one of the following group A; [Chemical 9] (in the formula, R each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted or unsubstituted heteroaryl group)) [Chemical 10] (In general formula (9), R9 to R12 and p have the same meaning as in general formula (3)). [9] An organic electroluminescent element as described in any one of [1] to [8], wherein it emits delayed fluorescence.

[10] An organic electroluminescent element as described in any one of [1] to [9], wherein it exhibits a maximum emission wavelength in the range of 700 nm to 1,500 nm.

[11] An organic semiconductor laser comprising an organic electroluminescent element as described in any one of [1] to

[10] .

[12] An organic semiconductor laser as described in

[11] , wherein the organic semiconductor laser has an optical resonator structure comprising a secondary Bragg scattering region surrounded by a primary Bragg scattering region.

[13] A thin film having on a substrate a layer containing a compound represented by general formula (1) as described in [1], a compound represented by general formula (4) as described in [2], a compound represented by general formula (5) as described in [5], or a compound represented by general formula (6) as described in [8].

[14] A compound represented by the following general formula (10), [Chemical 11] (in general formula (10), X1, X2, and R2 to R6 have the same meaning as in general formula (1); Ar2 and Ar3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl; R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring; R14 and R15 independently represent substituents containing aryl, and multiple R14s may be the same or different, at least one R14 is an electron-donating group containing aryl, and multiple R15s may be the same or different, at least one R15 is an electron-donating group containing aryl; n14 represents 1 to Ar The integers up to the number that can be substituted in 2, where n15 represents the integers up to the number that can be substituted in 1 to Ar 3).

[15] The compound as described in

[14] , wherein in the general formula (10), at least one of R 14 and R 15 is a substituted or unsubstituted diarylamine group.

[16] A compound represented by the following general formula (11), [Chemical 12] (in general formula (11), X1, X2, and R2 to R6 have the same meaning as in general formula (1); Ar4 to Ar7 each independently represent a substituted or unsubstituted aryl group, and multiple Ar4 and Ar5 may be the same or different, and multiple Ar6 and Ar7 may be the same or different; R16 and R17 each independently represent a substituent other than a substituted or unsubstituted diarylamine group, and multiple R16 and R17 may be the same or different; R16 and R2, R3 and R4, R4 and R5, R6 and R17 may form a ring together; n16 and n18 each independently represent an integer greater than or equal to 0 or 1, n17 and n19 each independently represent an integer greater than or equal to 1, n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5.

[17] A delayed fluorescent emitter comprising a compound as described in any one of

[14] to

[16] .

[18] An organic semiconductor laser comprising a compound as described in any one of

[14] to

[16] .

[19] An organic semiconductor laser as described in

[18] , wherein the organic semiconductor laser has an optical resonator structure comprising a secondary Bragg scattering region surrounded by a primary Bragg scattering region. [Effects of the Invention].

[0009] By means of the present invention, a compound, thin film, delayed phosphor, or organic electroluminescent element of an organic semiconductor laser that can achieve excellent light emission characteristics and excellent reduction of the ASE threshold of the NIR light emitter can be provided.

Implementation Method

[0011] Hereinafter, embodiments of the present invention will be described using drawings. Furthermore, in all drawings, the same symbols are used to mark the same constituent elements, and descriptions may be omitted. In addition, for example, "1 to 10" means "1 or more" to "10 or less" unless otherwise specified.

[0012] In this embodiment, the alkyl group can be any of a straight-chain, branched-chain, or cyclic form, preferably a straight-chain or branched-chain alkyl group. The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, further preferably 1 to 8 carbon atoms, and even more preferably 1 to 6 carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tributyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl). Examples of cyclic alkyl groups include: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclo[2.1.1]hexyl, and bicyclo[2.2.1]heptyl. The alkyl group may be substituted. Examples of substituents at this time include: alkoxy, aryl, aryloxy, acetyl, hydroxyl, halogen atom, nitro, diarylamino (9-carbazolyl, etc.) and cyano, with alkoxy, aryl, and aryloxy being preferred.

[0013] In this embodiment, the alkenyl group can be any of a straight-chain, branched-chain, or cyclic form, preferably a straight-chain or branched-chain alkyl group. The alkenyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, further preferably 2 to 8 carbon atoms, and even more preferably 2 to 6 carbon atoms. Examples of alkenyl groups include: vinyl, butadienyl, hexatrienyl, and 1-cyclohexenyl. The alkenyl group can be substituted. Examples of substituents include: alkoxy, aryl, aryloxy, acetyl, hydroxyl, halogen atom, nitro, diarylamino (9-carbazole, etc.), and cyano.

[0014] In this embodiment, the aryl group may have a structure containing a single aromatic ring or a structure containing two or more aromatic rings condensed together. Preferably, the aryl group has 6 to 22 carbon atoms forming a ring skeleton, more preferably 6 to 18 carbon atoms forming a ring skeleton, even more preferably 6 to 14 carbon atoms forming a ring skeleton, and even more preferably 6 to 10 carbon atoms forming a ring skeleton. Examples of aryl groups include: phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, 9-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 4-phenanthyl, 9-phenanthyl, 1-fused tetraphenyl, 2-fused tetraphenyl, 1-pyrene, and 2-pyrene. The aryl group may be substituted. Examples of substituents at this time include: alkyl, alkoxy, aryl, aryloxy, acetyl, hydroxyl, halogen atom, nitro, diarylamino (9-carbazolyl, etc.), and cyano, with alkyl, alkoxy, aryl, and aryloxy being preferred.

[0015] In this embodiment, the heteroaryl group may have a structure containing a single heteroaryl aromatic ring, or a structure containing two or more heteroaryl aromatic rings condensed together. The heteroaryl group may contain at least one heteroaryl aromatic ring and at least one aromatic ring. The heteroaryl group preferably has 5 to 22 ring skeleton forming atoms, more preferably 5 to 18 ring skeleton forming atoms, even more preferably 5 to 14 ring skeleton forming atoms, and even more preferably 5 to 10 ring skeleton forming atoms.

[0016] Examples of heteroaryl groups include: 2-thienyl, 3-thienyl, 2-furanyl, 3-furanyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl, 2-quinolinyl, 3-quinolinyl, 4-quinolinyl, 1-isoquinolinyl, and 3-isoquinolinyl. Other examples of heteroaryl groups include: benzofuranyl, pyrroleyl, indolyl, isoyindolyl, azaindolyl, benzothienyl, pyridinyl, quinolinyl, isoquinolinyl, imidazolyl, benzimidazolyl, pyrazolyl, oxazolyl, isoxazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, isothiazolyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, terpineyl, phthalazinyl, and quinazolinyl. Heteroaryl groups may be substituted. Examples of substituents at this time include: alkyl, alkoxy, aryl, aryloxy, hydroxyl, halogen atom, nitro, diarylamino (9-carbazolyl, etc.) and cyano, with alkyl, alkoxy, aryl and aryloxy being preferred.

[0017] In this embodiment, the alkyl group of the alkoxy group can be the alkyl group, and the aryl group of the aryloxy group can be the aryl group. In this embodiment, the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0018] [Compounds] The compounds of this embodiment include those represented by the general formula (1).

[0019] [Chemical 13]

[0020] In general formula (1), X1 and X2 independently represent a halogen atom, a halogenated alkyl group, or a halogenated aryl group, respectively, and at least one of X1 and X2 represents a halogenated alkyl group or a halogenated aryl group. Preferably, one of X1 and X2 is a halogenated alkyl group or a halogenated aryl group and the other is a halogen atom, or either X1 or X2 is a halogenated alkyl group or a halogenated aryl group.

[0021] The alkyl halide may have 1 to 3 halogen atoms bonded to the carbon atom at the end of the alkyl group, or 1 to 2 halogen atoms bonded to the carbon atom other than the end of the alkyl group. The halogen atoms are preferably fluorine, chlorine, or bromine, and more preferably fluorine. Examples of alkyl halide include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorodibutyl, perfluoroterbutyl, perfluoropentyl, trichloromethyl, and tribromomethyl, etc., having 1 to 5 carbon atoms; more preferably, trifluoromethyl, perfluoroethyl, perfluoropropyl, and perfluoroisopropyl, etc., having 1 to 3 carbon atoms; and more preferably, trifluoromethyl and perfluoroethyl, etc., having 1 to 2 carbon atoms.

[0022] The aryl halide may have one or more halogen atoms that can be substituted bonded to the carbon of the aryl group. The halogen atoms are preferably fluorine, chlorine, or bromine atoms, and more preferably fluorine atoms. Specific examples of aryl halide include: monofluorophenyl, difluorophenyl, trifluorophenyl, perfluorophenyl, etc. (fluorophenyl groups), perfluoronaphthyl, etc. (fluoronaphthyl groups), pentylchlorophenyl, etc. (chlorophenyl groups), pentylbromophenyl, etc. (bromophenyl groups), etc., with 6 to 18 carbon atoms. Preferred are trifluorophenyl, perfluorophenyl, etc. (fluorophenyl groups), perfluoronaphthyl, etc. (fluoronaphthyl groups), etc., with 6 to 18 carbon atoms. More preferably are trifluorophenyl, perfluorophenyl, etc. (fluorophenyl groups), etc., with 6 to 18 carbon atoms.

[0023] R1 to R6 each independently represent a hydrogen atom or a substituent. Preferably, the substituents of R1 to R6 are substituted or unsubstituted alkyl groups having 1 to 16 carbon atoms, substituted or unsubstituted aryl groups having 6 to 18 carbon atoms, substituted or unsubstituted heteroaryl groups having 6 to 18 carbon atoms, substituted or unsubstituted alkoxycarbonyl groups having 1 to 16 carbon atoms, substituted or unsubstituted aryloxycarbonyl groups having 6 to 20 carbon atoms, and halogen atoms. In a preferred embodiment, R1 is a substituent, R2, R3, R5, and R6 are hydrogen atoms, and R4 is a hydrogen atom or a substituent. In a preferred embodiment, R1 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, R2, R3, R5, and R6 are hydrogen atoms, and R4 is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, a substituted or unsubstituted heteroaryl group having 6 to 18 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 16 carbon atoms, a substituted or unsubstituted aryloxycarbonyl group having 6 to 20 carbon atoms, a halogen atom, or a group containing a boron diketone ring. Furthermore, the carbon number does not include carbon atoms of a carbonyl group.

[0024] R 7 represents the base represented by the following formula (2) or general formula (3).

[0025] [Chemical 14]

[0026] In general formula (2), Ar1 represents aryl, aryl-substituted aryl, heteroaryl-substituted aryl, heteroaryl, aryl-substituted heteroaryl, or heteroaryl-substituted heteroaryl, and R8 represents a substituent. There may be multiple R8s, which may be the same or different, and at least one R8 is an electron-donating group. n8 represents an integer from 1 to the number of Ar1 that can be substituted.

[0027] In general formula (2), Ar 1 represents aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-substituted heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl.

[0028] Examples of aryl groups include: phenyl, 1-naphthyl, 2-naphthyl, 1-anthrayl, 2-anthrayl, and 9-anthrayl, with phenyl, 1-naphthyl, and 2-anthrayl being more preferred. Examples of aryl-substituted aryl groups include: phenyl-substituted phenyl, phenyl-substituted 1-anthrayl, etc. The two or more aromatic rings in the aryl-substituted aryl group can be directly bonded or bonded together via substituted or unsubstituted linking groups such as methylene groups to form further rings.

[0029] Examples of heteroaryl-substituted aryl groups include: thienyl-substituted arylphenyl, thienyl-substituted 1-arylnaphthyl, furanyl-substituted arylphenyl, furanyl-substituted 1-arylnaphthyl, benzothienyl-substituted arylphenyl, benzothienyl-substituted 1-arylnaphthyl, benzofuranyl-substituted arylphenyl, benzofuranyl-substituted 1-arylnaphthyl, etc.

[0030] Examples of aryl groups include: pyrenyl, pyrenofuryl, benzopyrenyl, benzopyrenofuryl, etc.

[0031] Examples of aryl-substituted heteroaryl groups include: phenyl-substituted thiophene group, phenyl-substituted furanyl group, phenyl-substituted benzothiophene group, phenyl-substituted benzofuranyl group, etc.

[0032] Examples of heteroaryl-substituted heteroaryl groups include: thienyl-substituted thienyl, thienyl-substituted furanyl, thienyl-substituted benzo[a]thienyl, thienyl-substituted benzo[a]thienyl, furanyl-substituted thienyl, furanyl-substituted benzo[a]thienyl, furanyl-substituted benzo[a]thienyl, furanyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, benzo[a]thienyl-substituted benzo[a]thienyl, etc.

[0033] R 8 in general formula (2) represents a substituent. Examples of substituents include: halogen atom, alkyl, alkenyl, alkynyl, aryl, heteroaryl, halogen atom, hydroxyl, nitro, carboxyl, cyano, alkoxy, aryloxy, acetyl, acetyloxy, aminomethylacetyloxy (alkoxycarbonyloxy, etc.), primary amino, alkylamino, arylamino, dialkylamino, diarylamino, alkylarylamino, acetylamino, aminocarbonylamino, alkoxycarbonylamino, aryloxycarbonyl Amino, aminesulfonylamino, alkylsulfonylamino, arylsulfonylamino, alkylthio, arylthio, sulfonyl, aminesulfonyl, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aryloxycarbonyl, aminomethyl, amideimino, alkoxysulfonyl, aryloxysulfonyl, trialkylsilyl, trialkylsilyloxy, monovalent groups derived from compounds represented by the general formula (1), etc. These groups may be further substituted.

[0034] In general formula (2), n8 represents an integer from 1 to the number of positions in Ar 1 that can be substituted. n8 is preferably 1 to 3, more preferably 1 or 2. When n8 is 2 or more, each R 8 may be the same or different. At least one R 8 is an electron-donating base. In this embodiment, an electron-donating base refers to a substituent with a Hammett σp value of less than 0. The electron-donating base is preferably a substituent with a Hammett σp value of less than -0.1, more preferably a substituent with a Hammett σp value of less than -0.2. The Hammett σp value is calculated by the following formula (I). Formula (I): σp = logKX - logKH

[0035] In formula (I), KH represents the ionization constant of benzoic acid in water at 25°C, and KX represents the ionization constant of benzoic acid with a substituent at the para position in water at 25°C. Examples of electron-donating groups include: hydroxyl, alkoxy, primary amino, alkylamino, arylamino, dialkylamino, diarylamino, alkylarylamino, aminocarbonylamino, alkoxycarbonylamino, and trialkylsilyl.

[0036] [Chemical 15]

[0037] In general formula (3), R9 to R13 each independently represent a hydrogen atom or a substituent. The substituents of R9 to R13 have the same meaning as the substituent of R8 in general formula (2). Preferred examples of substituents of R9 to R12 include alkyl, aryl, and heteroaryl groups, more preferably alkyl. Preferred examples of substituents of R13 include alkenyl, alkynyl, aryl, heteroaryl, and monovalent groups derived from the compounds represented by the general formula (1), more preferably alkenyl and the monovalent groups. These alkyl, aryl, heteroaryl, alkenyl, and alkynyl groups may be further substituted. In a preferred embodiment of general formula (3), R9 to R12 each independently represent a hydrogen atom or an alkyl group, and R13 is a substituent. In a preferred embodiment of general formula (3), R9 to R12 are independently hydrogen atoms, and R13 is a substituted or unsubstituted alkenyl group. In general formula (3), p represents an integer from 0 to 2.

[0038] R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6, R6 and R7 can together represent a ring.

[0039] R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6, R6 and R7 are preferably substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, or substituted or unsubstituted alkynyl, more preferably substituted or unsubstituted alkyl, or substituted or unsubstituted alkenyl, and even more preferably substituted or unsubstituted alkyl.

[0040] Examples of substituents that can be substituted among alkyl, alkenyl, and alkynyl groups include: alkyl, alkoxy, aryl, and aryloxy groups. R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6, R6 and R7 can together form a ring preferably having 4 to 10 ring skeleton forming atoms, more preferably a ring having 5 to 8 ring skeleton forming atoms, and even more preferably a ring having 5 to 7 ring skeleton forming atoms. Examples of rings include: cyclopentane ring, cyclohexane ring, and cycloheptane ring. It is preferred that R3 and R4, or R4 and R5, form a ring together.

[0041] The compound represented by general formula (1) includes the compound represented by general formula (4) below.

[0042] [Chemical 16]

[0043] In general formula (4), X1, X2, and R2 to R6 have the same meaning as in general formula (1).

[0044] Ar 2 and Ar 3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-substituted heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl. The terms aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-substituted aryl, and heteroaryl-substituted aryl have the same meaning as the examples in general formula (2).

[0045] In this embodiment, Ar2 and Ar3 are preferably independently benzene, naphthalene, anthracene, fumonisin, thiophene, furan, benzothiophene, benzofuran, phenyl-substituted thiophene, phenyl-substituted furan, phenyl-substituted benzothiophene, or phenyl-substituted benzofuran, and more preferably benzene, naphthalene, anthracene, or fumonisin.

[0046] R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring. The formed rings have the same meaning as those in the example of general formula (1).

[0047] R14 and R15 represent substituents independently. There may be multiple R14s, which may be the same or different. At least one R14 is an electron-donating group. There may be multiple R15s, which may be the same or different. At least one R15 is an electron-donating group.

[0048] Regarding the substituents and electron-donating groups in R14 and R15 of general formula (4), refer to the description of the substituents exemplified as R8 in general formula (2) and the electron-donating groups contained therein. The electron-donating groups in R14 and R15 are preferably substituted or unsubstituted diarylamine groups. Examples of diarylamine groups include: diphenylamino, di(1-naphthyl)amino, di(2-naphthyl)amino, and 9-carbazolyl. The diarylamine group may be substituted. Examples of substituents that substitute for the diarylamine group include: alkyl, alkoxy, thioalkoxy, trialkylsilyl, aryl, aryloxy, and diarylamine (9-carbazolyl, etc.). In this embodiment, it is more preferred that at least one of R14 and R15 is a substituted or unsubstituted diarylamine group. Furthermore, R14 and R15 can be bonded to substituents of aryl or heteroaryl groups.

[0049] n14 represents an integer up to the number of substituted positions from 1 to Ar 2. When n14 is 2 or more, each R 14 may be the same or different. At least one R 14 is an electron-donating base. n15 represents an integer up to the number of substituted positions from 1 to Ar 3. When n15 is 2 or more, each R 15 may be the same or different. At least one R 15 is an electron-donating base. n14 and n15 are preferably 1 to 3, more preferably 1 or 2.

[0050] The compound represented by general formula (1) includes the compound represented by general formula (10) below.

[0051] [Chemical 17]

[0052] In general formula (10), X1, X2, and R2~R6 have the same meaning as in general formula (1).

[0053] Ar 2 and Ar 3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl. The terms aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-substituted aryl, and heteroaryl-substituted aryl have the same meaning as the examples in general formula (2).

[0054] In this embodiment, Ar2 and Ar3 are preferably independently benzene, naphthalene, anthracene, fumonisin, thiophene, furan, benzothiophene, benzofuran, phenyl-substituted thiophene, phenyl-substituted furan, phenyl-substituted benzothiophene, or phenyl-substituted benzofuran.

[0055] R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring. The formed rings have the same meaning as those in the example of general formula (1).

[0056] n14 represents an integer up to the number of substituted positions from 1 to Ar 2. When n14 is 2 or more, each R 14 may be the same or different. At least one R 14 is an electron-donating base. n15 represents an integer up to the number of substituted positions from 1 to Ar 3. When n15 is 2 or more, each R 15 may be the same or different. At least one R 15 is an electron-donating base. n14 and n15 are preferably 1 to 3, more preferably 1 or 2.

[0057] R14 and R15 each independently represent substituents containing aryl groups. There may be multiple R14s that are the same or different. At least one R14 is an electron-donating group containing aryl groups. There may be multiple R15s that are the same or different. At least one R15 is an electron-donating group containing aryl groups.

[0058] R14 and R15 in general formula (10) are substituents containing aryl and electron-donating groups containing aryl. Examples of substituents containing aryl include aryl, heteroaryl, aryloxy, arylamine, diarylamine, alkylarylamine, aryloxycarbonylamine, arylsulfonylamine, arylthio, arylsulfinyl, arylsulfonyl, aryloxycarbonyl, and aryloxysulfonyl. Examples of electron-donating groups containing aryl include aryl, heteroaryl, aryloxy, arylamine, diarylamine, alkylarylamine, and arylthio.

[0059] The electron-donating group containing an aryl group in R14 and R15 is preferably a substituted or unsubstituted diarylamine. Examples of diarylamines include diphenylamino, di(1-naphthyl)amino, di(2-naphthyl)amino, and 9-carbazolyl. The diarylamine may be substituted. Examples of substituents for the diarylamine include alkyl, alkoxy, thioalkoxy, trialkylsilyl, aryl, aryloxy, and diarylamines (9-carbazolyl, etc.). In this embodiment, it is more preferred that at least one of R14 and R15 is a substituted or unsubstituted diarylamine. Furthermore, R14 and R15 may be bonded to a substituent of an aryl group or a substituent of a heteroaryl group.

[0060] n14 represents an integer up to the number of substituted positions from 1 to Ar 2. When n14 is 2 or more, each R 14 may be the same or different. At least one R 14 is an electron-donating base. n15 represents an integer up to the number of substituted positions from 1 to Ar 3. When n15 is 2 or more, each R 15 may be the same or different. At least one R 15 is an electron-donating base. n14 and n15 are preferably 1 to 3, more preferably 1 or 2.

[0061] The compound represented by general formula (1) includes the compound represented by general formula (5) below.

[0062] [Chemical 18]

[0063] In general formula (5), X1, X2, and R2 to R6 have the same meaning as in general formula (1).

[0064] Ar 4 to Ar 7 each independently represent a substituted or unsubstituted aryl group. Multiple Ar 6 and Ar 7 groups may be the same or different, and multiple Ar 4 and Ar 5 groups may be the same or different. Ar 4 to Ar 7 are preferably substituted or unsubstituted aryl groups. This allows for the expansion of the overall conjugation system of the compound, achieving longer wavelength absorption or luminescence.

[0065] Ar 4 and Ar 5, or Ar 6 and Ar 7, may be directly bonded or bonded together via substituted or unsubstituted methylene groups to form a ring. Examples of -N(Ar 4)(Ar 5) and -N(Ar 6)(Ar 7) include: substituted or unsubstituted diphenylamino, substituted or unsubstituted di(1-naphthyl)amino, substituted or unsubstituted di(2-naphthyl)amino, and substituted or unsubstituted 9-carbazole.

[0066] R16 and R17 each independently represent a substituent other than a substituted or unsubstituted diarylamine group. Multiple R16 and R17 groups may be the same or different. Examples of substituents for R16 and R17 can be referenced to those for R8 in general formula (2). Preferably, they are substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aryloxy groups, and substituted or unsubstituted heteroaryl groups.

[0067] R16 and R2, R3 and R4, R4 and R5, R6 and R17 can form a ring together. The ring in this case has the same meaning as the ring in the general formula (1).

[0068] n16 and n18 each independently represent integers greater than or equal to 0 or 1, preferably 0 or 1. n17 and n19 each independently represent integers greater than or equal to 1, preferably 1 to 3. n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5.

[0069] The compound represented by general formula (1) includes the compound represented by general formula (11).

[0070] [Chemical 19]

[0071] In general formula (11), X1, X2, and R2 to R6 have the same meaning as in general formula (1).

[0072] Ar 4 to Ar 7 each independently represent a substituted or unsubstituted aryl group. Multiple Ar 6 and Ar 7 groups may be the same or different, and multiple Ar 4 and Ar 5 groups may be the same or different. Ar 4 to Ar 7 are preferably substituted or unsubstituted aryl groups. This allows for the expansion of the overall conjugation system of the compound, achieving longer wavelengths of absorption or luminescence.

[0073] Ar 4 and Ar 5, or Ar 6 and Ar 7, can be directly bonded or bonded together via substituted or unsubstituted methylene groups to form a ring. Examples of -N(Ar 4)(Ar 5) and -N(Ar 6)(Ar 7) include: substituted or unsubstituted diphenylamino, substituted or unsubstituted di(1-naphthyl)amino, substituted or unsubstituted di(2-naphthyl)amino, and substituted or unsubstituted 9-carbazole.

[0074] R16 and R17 each independently represent a substituent other than a substituted or unsubstituted diarylamine group. Multiple R16 and R17 groups may be the same or different. Examples of substituents for R16 and R17 can be referenced to those for R8 in general formula (2). Preferably, they are substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aryloxy groups, and substituted or unsubstituted heteroaryl groups.

[0075] R16 and R2, R3 and R4, R4 and R5, R6 and R17 can form a ring together. The ring in this case has the same meaning as the ring in the general formula (1).

[0076] n16 and n18 each independently represent integers greater than or equal to 0 or 1, preferably 0 or 1. n17 and n19 each independently represent integers greater than or equal to 1, preferably 1 to 3. n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5.

[0077] The compound represented by general formula (1) includes the compound represented by general formula (6) below.

[0078] [Chemical 20]

[0079] In general formula (6), X1, X2, and R2 to R6 have the same meaning as in general formula (1). X1' and X2' have the same meaning as X1 and X2, but may be different from X1 and X2.

[0080] R2'~R6' represent hydrogen atoms or substituents independently. The substituents of R2'~R6' have the same meaning as the substituents of R2~R6 in general formula (1).

[0081] R 18 and R 19 each independently represent one of the following groups A.

[0082] [Chemical 21]

[0083] In the formula, R independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted or unsubstituted heteroaryl group.

[0084] In group A, the substituents of group B are preferred.

[0085] [Chemical 22]

[0086] In group A, it is more preferably a substituent of group C below.

[0087] [Chemical 23]

[0088] R18 and R2, R3 and R4, R4 and R5, R19 and R2', R3' and R4', and R4' and R5' can form a ring together, R6 can form a ring with an A bond, and R6' can form a ring with an A bond. The ring has the same meaning as the ring illustrated in general formula (1).

[0089] A represents the linking base represented by the following general formula (7) or general formula (9).

[0090] [Chemical 24]

[0091] In general formula (7), n is an integer from 0 to 4, m is 0 or 1, A' represents an alkoxy group having 1 to 12 carbon atoms, and A'' represents the group represented by the following formula (8).

[0092] [Chemical 25]

[0093] In general formula (8), X1'' and X2'' have the same meaning as X1 and X2, and may be different from X1 and X2 in general formula (6).

[0094] R 2'' to R 6'' each independently represent a hydrogen atom or a substituent, X 1'' and X 2'' represent a halogen atom, a halogenated alkyl group or a halogenated aryl group, and R 20 represents one of the group A.

[0095] [Chemical 26]

[0096] In general formula (9), R9~R12 and p have the same meaning as in general formula (3).

[0097] In a preferred first embodiment of formula (6), A is an o-phenyl group represented by formula (7). Preferably, R18 and R19 are each independently one of the group B.

[0098] In a preferred second embodiment of formula (6), A is an o-phenyl group represented by formula (7), m is 0, n is 0, and R 18 and R 19 are each independently one of the C groups.

[0099] In a preferred third embodiment of formula (6), A is the meta-phenyl group represented by formula (7). Preferably, R18 and R19 are each independently one of the group B.

[0100] In a preferred fourth embodiment of formula (6), A is the meta-phenyl group represented by formula (7), and R18 and R19 are each independently one of the C groups.

[0101] In a preferred fifth embodiment of formula (6), A is the meta-phenyl group represented by formula (7), m is 0, and R 18 and R 19 are each independently one of the C groups. n is preferably 3.

[0102] In a preferred sixth embodiment of formula (6), A is the p-phenylene represented by formula (7). Preferably, R18 and R19 are each independently one of the group B.

[0103] In a preferred seventh embodiment of formula (6), A is the p-phenylene represented by formula (7), and R18 and R19 are each independently one of the C groups.

[0104] In a preferred eighth embodiment of formula (6), A is p-phenylene as represented by formula (7), m is 0, and R 18 and R 19 are each independently one of the C group. A' is preferably an alkoxy group having 1 to 8 carbon atoms.

[0105] In a preferred ninth embodiment of equation (6), A is the linking base represented by equation (9). Preferably, R 18 and R 19 are each independently one of the group B.

[0106] In a preferred tenth embodiment of equation (6), A is the linking base represented by equation (9), and R 18 and R 19 are each independently one of the C groups.

[0107] In the preferred eleventh embodiment of formula (6), R2 and R2', R3 and R3', R4 and R4', R5 and R5', R6 and R6', and R18 and R19 are the same.

[0108] The following are specific examples of compounds represented by general formula (1) of this embodiment. It is not limited to these specific examples.

[0109] [Chemistry 27]

[0110] [Chemistry 28]

[0111] [Chemistry 29]

[0112] Regarding the molecular weight of the compound represented by general formula (1), for example, when intending to form an organic layer containing the compound represented by general formula (1) into a film by vapor deposition, it is preferably 1,500 or less, more preferably 1,200 or less, even more preferably 1,000 or less, and even more preferably 800 or less. The lower limit of the molecular weight is the molecular weight of the smallest compound represented by general formula (1).

[0113] The compounds represented by general formula (1) can be formed into films by coating, regardless of their molecular weight. Compounds with larger molecular weights can be formed into films by coating.

[0114] As an application of this embodiment, compounds containing multiple structures represented by general formula (1) can be used as luminescent materials.

[0115] For example, it is possible to pre-introduce a polymerizable group into the structure represented by general formula (1), and use the polymer obtained by polymerizing the polymerizable group as a luminescent material. Specifically, it is possible to prepare a monomer having a polymerizable functional group in any of R1 to R7 in general formula (1), and homopolymerize or copolymerize it with other monomers to prepare a polymer containing repeating units, and use the polymer as a luminescent material. Alternatively, it is possible to react a compound containing the structure represented by general formula (1) to form a dimer or trimer, and use the dimer or trimer as a luminescent material.

[0116] As an example of a polymer having repeating units containing the structure represented by the general formula (1), polymers containing the structure represented by the following formula (31) or formula (32) can be listed.

[0117] [Chemistry 30]

[0118] [Chemistry 31]

[0119] In formulas (31) and (32), n is an integer, Q represents a base containing the structure represented by formula (1), and L1 and L2 represent linking groups, respectively. The linking group preferably has 0 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and even more preferably 2 to 10 carbon atoms. The linking group preferably has the structure represented by -X11-L11-, where X11 represents an oxygen atom or a sulfur atom, preferably an oxygen atom, and L11 represents a linking group, preferably a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and more preferably a substituted or unsubstituted alkyl group, or a substituted or unsubstituted phenyl group having 1 to 10 carbon atoms.

[0120] In general formulas (31) and (32), R 101, R 102, R 103 and R 104 each independently represent a substituent, preferably representing a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a halogen atom, more preferably representing an unsubstituted alkyl group having 1 to 3 carbon atoms, an unsubstituted alkoxy group having 1 to 3 carbon atoms, a fluorine atom or a chlorine atom, and even more preferably representing an unsubstituted alkyl group having 1 to 3 carbon atoms or an unsubstituted alkoxy group having 1 to 3 carbon atoms.

[0121] The linking groups represented by L1 and L2 can be bonded to any of R1 to R7 of the structure of formula (1) constituting Q. Two or more linking groups can be bonded to one of the bases represented by Q to form a cross-linked structure or a mesh structure.

[0122] Specific examples of the structure of repeating units can be listed as the structures represented by the following equations (33) to (36).

[0123] [Chemistry 32]

[0124] A polymer having repeating units containing any of the structures represented by formulas (33) to (36), where n is an integer, can be synthesized by introducing hydroxyl groups into any of R1 to R7 of formula (1), and then polymerizing the polymeric group by reacting the hydroxyl group, which is a linker, with the following compound to introduce a polymeric group.

[0125] [Chemistry 33]

[0126] A polymer containing the structure represented by formula (1) may be a polymer containing only repeating units having the structure represented by formula (1), or it may further contain repeating units having other structures. The repeating unit containing the structure represented by formula (1) in the polymer may be only one type, or it may be two or more types. As an example of a repeating unit that does not have the structure represented by formula (1), repeating units derived from monomers used in common copolymerization can be listed. As an example of a repeating unit, repeating units derived from monomers having vinyl unsaturated bonds, such as ethylene and styrene, can be listed.

[0127] (Synthetic method of the compound represented by general formula (1)) The compound represented by general formula (1) can be synthesized by a known reaction. For example, it can be synthesized as shown in reaction formula 1 or reaction formula 2 below.

[0128] [Chemistry 34]

[0129] In reaction formulas 1 and 2, X1, X2, and R1 to R7 are as defined in general formula (1). When R2, R3, R5, and R6 are hydrogen atoms, the aldehyde used in the second step is represented by R1CHO or R7CHO. A mixture of R1CHO and R7CHO can be used. The second step can be carried out after purification following the first step, or it can be carried out without purification following the first step. In reaction formula 1, as reaction conditions, in the first step, the reaction temperature is preferably 0°C to room temperature, and the reaction time is preferably 24 hours to 72 hours; in the second step, the reaction temperature is preferably 60°C to reflux, and the reaction time is preferably 4 hours to 24 hours. In reaction formula 2, in the first step, the reaction temperature is preferably room temperature, and the reaction time is preferably 1 hour. In the second step, the reaction temperature is preferably 60°C to reflux, and the reaction time is preferably 4 to 24 hours. The reaction conditions can be appropriately determined. For details of the reaction, please refer to the synthesis example described later.

[0130] (Organic electroluminescent element) The organic electroluminescent element of this embodiment includes the compound represented by the general formula (1) of this embodiment.

[0131] The compound of this embodiment is effectively used as a luminescent material in an organic electroluminescent element. Therefore, the compound represented by general formula (1) of this embodiment can be effectively used as a luminescent material in the luminescent layer of an organic electroluminescent element. The compound represented by general formula (1) contains a delayed-fluorescent material that emits delayed fluorescence. That is, this embodiment also provides an invention having a delayed-fluorescent body with the structure represented by general formula (1), an invention using the compound represented by general formula (1) as a delayed-fluorescent body, and an invention related to a method of emitting delayed fluorescence using the compound represented by general formula (1). The organic electroluminescent element using the compound as a luminescent material has the characteristics of emitting delayed fluorescence and high luminous efficiency. The principle of this characteristic can be explained below.

[0132] In organic light-emitting diodes (OLEDs), carriers are injected into the light-emitting material from both positive and negative electrodes to generate an excited-state light-emitting material, which then emits light. Typically, in carrier-injection type OLEDs, 25% of the generated excitons are excited to the excited singlet state, while the remaining 75% are excited to the excited triplet state. Therefore, phosphorescence, which utilizes light emitted from the excited triplet state, has high energy utilization efficiency. However, due to the long lifetime of the excited triplet state, energy deactivation can occur due to saturation of the excited state or interaction with the excitons in the excited triplet state, resulting in generally low quantum yield for phosphorescence. On the other hand, delayed phosphors, after energy migration to the excited triplet state via intersystem crossing, undergo reverse intersystem crossing to the excited singlet state and emit fluorescence due to triplet-triplet state extinguishing or thermal absorption. In OLEDs, thermally activated delayed phosphors based on thermal absorption are considered particularly useful. In the case of using delayed phosphors in organic electroluminescent devices, excitons in the excited singlet state still emit fluorescence as usual. On the other hand, excitons in the excited triplet state absorb the heat emitted by the element, undergo intersystem crossing to the excited singlet state, and emit fluorescence. In this case, since the emission originates from the excited singlet state, it is emission with the same wavelength as fluorescence, and because the lifetime of the light produced by the reverse intersystem crossing from the excited triplet state to the excited singlet state is longer than that of ordinary fluorescence or phosphorescence, it is observed as further delayed fluorescence. This can be defined as delayed fluorescence. If this thermally activated exciton transfer mechanism is used, the proportion of compounds that typically generate only 25% of the excited singlet state can be increased to more than 25% by absorbing thermal energy after carrier injection. If a compound that emits strong and delayed fluorescence even at low temperatures below 100°C is used, the heat of the element can fully generate intersystem crossing from the self-excited triplet state to the excited singlet state and emit delayed fluorescence, thus dramatically improving the luminous efficiency.

[0133] By using the compound represented by the general formula (1) of this embodiment as the luminescent material of the luminescent layer, excellent organic luminescent devices such as organic photoluminescence devices (organic PL devices) or organic electroluminescence devices (organic EL devices) can be provided. At this time, the compound represented by the general formula (1) of this embodiment can have the function of assisting the luminescence of other luminescent materials contained in the luminescent layer as a so-called auxiliary dopant. That is, the compound represented by the general formula (1) of this embodiment contained in the luminescent layer can have the lowest excited singlet state energy level between the lowest excited singlet state energy level of the host material contained in the luminescent layer and the lowest excited singlet state energy level of other luminescent materials contained in the luminescent layer.

[0134] Furthermore, the organic electroluminescent element has a structure comprising at least an anode, a cathode, and an organic layer formed between the anode and the cathode. The organic layer includes at least a light-emitting layer, which may be formed solely by the light-emitting layer, or may have one or more organic layers in addition to the light-emitting layer. Examples of such organic layers include: hole transport layer, hole injection layer, electron blocking layer, hole blocking layer, electron injection layer, electron transport layer, exciton blocking layer, etc. The hole transport layer may be a hole injection transport layer with hole injection function, and the electron transport layer may be an electron injection transport layer with electron injection function. A specific structure of an organic electroluminescent element is illustrated in FIG19. In FIG19, 10 represents an organic electroluminescent element, 11 represents a substrate, 12 represents an anode, 13 represents a hole injection layer, 14 represents a hole transport layer, 15 represents a light-emitting layer, 16 represents an electron transport layer, and 17 represents a cathode.

[0135] The components and layers of the organic electroluminescent element will be described below.

[0136] (Substrate) The organic electroluminescent element of this embodiment is preferably supported on a substrate. There are no particular limitations on the substrate, as long as it is a substrate commonly used in organic electroluminescent elements, such as a substrate containing glass, transparent plastic, quartz, silicon, etc.

[0137] (Anode) The anode in an organic electroluminescent element is preferably formed from electrode materials such as metals, alloys, electrically conductive compounds, or mixtures thereof, which have a high work function (4 eV or higher). Specific examples of such electrode materials include: metals such as Au; conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO. Alternatively, amorphous materials such as IDIXO (In2O3-ZnO) that can form transparent conductive films can also be used. The anode can be formed into a thin film using methods such as vapor deposition or sputtering, and a pattern of the desired shape can be formed using photolithography. Alternatively, if pattern precision is not critical (approximately 100 μm or higher), a pattern can be formed by separating the desired shape of the mask during the vapor deposition or sputtering of the electrode material. Alternatively, when using a coatable material such as an organic conductive compound, a wet film formation method such as printing or coating can be used. When light is emitted from the anode, it is ideal to have a transmittance greater than 10%, and the sheet resistance of the anode is preferably less than several hundred Ω / m². Furthermore, the film thickness also depends on the material, and can typically be selected in the range of 10 nm to 1,000 nm, preferably 10 nm to 200 nm.

[0138] (Cathode) On the other hand, the cathode is preferably formed from electrode materials such as a metal with a low work function (below 4 eV) (called an electron-injecting metal), an alloy or electrically conductive compound with a low work function (below 4 eV), and mixtures thereof. Specific examples of such electrode materials include: sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / alumina (Al₂O₃) mixture, indium, lithium / aluminum mixture, rare earth metals, etc. Among these, in terms of electron injection performance and durability against oxidation, a mixture of an electron-injecting metal and a second metal that is a metal with a larger and more stable work function than the electron-injecting metal is suitable, such as magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / alumina (Al₂O₃) mixture, lithium / aluminum mixture, aluminum, etc. The cathode can be manufactured by forming a thin film of these electrode materials using methods such as vapor deposition or sputtering. Furthermore, the sheet resistance of the cathode is preferably below several hundred Ω / m², and the film thickness is typically selected within the range of 10 nm to 5 μm, preferably 50 nm to 200 nm. Moreover, to allow the emitted light to pass through, it is suitable if either the anode or cathode of the organic electroluminescent element is transparent or translucent, thus increasing the luminous brightness.

[0139] In addition, a transparent conductive material listed in the description of the anode is used on the cathode, thereby forming a transparent or translucent cathode. By using it, an element in which both the anode and the cathode are transparent can be made.

[0140] (Emitting Layer) The emitting layer is a layer that emits light after generating excitons by recombination of holes and electrons injected from the anode and cathode, respectively. A luminescent material may be used alone in the emitting layer, but it is preferable to include both a luminescent material and a host material. As the luminescent material, one or more compounds selected from the group of compounds represented by general formula (1) of this embodiment may be used. To enable the organic electroluminescent element of this embodiment to exhibit high luminous efficiency, it is important to encapsulate the singlet and triplet excitons generated in the luminescent material within the luminescent material. Therefore, it is preferable to use a host material in addition to the luminescent material in the emitting layer. As the host material, an organic compound may be used that has at least one higher value for excitation singlet energy or excitation triplet energy than the luminescent material of this embodiment. As a result, the singlet and triplet excitons generated in the luminescent material of this embodiment can be encapsulated within the molecules of the luminescent material of this embodiment, thereby maximizing its luminous efficiency. However, even if singlet and triplet excitons cannot be fully encapsulated, high luminous efficiency can sometimes be achieved. Therefore, if the host material can achieve high luminous efficiency, it can be used in this embodiment without particular limitations. In the organic light-emitting element or organic electroluminescent element of this embodiment, luminescence is generated by the luminescent material of this embodiment contained in the self-emissive layer. This luminescence includes both fluorescence and delayed fluorescence. Part of the luminescence or localized luminescence may originate from the host material.

[0141] When using a host material, the amount of the compound of this embodiment as the luminescent material contained in the luminescent layer is preferably 0.1% by weight or more, more preferably 1% by weight or more, and preferably 50% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less. As the host material in the luminescent layer, it is preferably an organic compound that has hole transport capability, electron transport capability, prevents the long wavelength of luminescence, and thus has a high glass transition temperature.

[0142] (Injection Layer) An injection layer is a layer placed between the electrode and the organic layer to reduce the driving voltage or increase the luminous brightness. There are hole injection layers and electron injection layers, which can exist between the anode and the luminescent layer or hole transport layer, and between the cathode and the luminescent layer or electron transport layer. The injection layer can be set as needed.

[0143] (Blocking Layer) A blocking layer is a layer that blocks the diffusion of charges (electrons or holes) and / or excitons present in the light-emitting layer outwards. An electron blocking layer may be disposed between the light-emitting layer and the hole transport layer to block electrons from passing through the light-emitting layer towards the hole transport layer. Similarly, a hole blocking layer may be disposed between the light-emitting layer and the electron transport layer to block holes from passing through the light-emitting layer towards the electron transport layer. In addition, the blocking layer can also be used to block excitons from diffusing outwards from the light-emitting layer. That is, the electron blocking layer and the hole blocking layer can also function as exciton blocking layers. In this specification, "electron blocking layer" or "exciton blocking layer" is used to mean a layer that is contained in one layer and has the functions of both an electron blocking layer and an exciton blocking layer.

[0144] (Hole Blocking Layer) In a broad sense, a hole blocking layer functions as an electron transport layer. It transports electrons and blocks holes from reaching the electron transport layer, thereby increasing the probability of recombination between electrons and holes in the luminescent layer. The material used for the hole blocking layer can be any of the electron transport layer materials described later, depending on the requirements.

[0145] (Electron blocking layer) In a broad sense, the electron blocking layer has the function of transporting holes. The electron blocking layer has the function of transporting holes and blocking electrons from reaching the hole transport layer, thereby increasing the probability of electrons and holes recombinating in the luminescent layer.

[0146] (Exciton Blocking Layer) An exciton blocking layer is a layer used to block excitons generated by the recombination of holes and electrons in the light-emitting layer from diffusing to the charge transport layer. By inserting this layer, excitons can be efficiently sealed into the light-emitting layer, thereby improving the luminous efficiency of the device. The exciton blocking layer can be inserted adjacent to the light-emitting layer on either the anode side or the cathode side, or simultaneously on both sides. That is, when an exciton blocking layer is present on the anode side, it can be inserted adjacent to the light-emitting layer between the hole transport layer and the light-emitting layer; when inserted on the cathode side, it can be inserted adjacent to the light-emitting layer between the light-emitting layer and the cathode. In addition, a hole injection layer or an electron blocking layer may be present between the anode and the exciton blocking layer adjacent to the anode side of the light-emitting layer, and an electron injection layer, an electron transport layer, or a hole blocking layer may be present between the cathode and the exciton blocking layer adjacent to the cathode side of the light-emitting layer. When a blocking layer is configured, it is preferable that at least one of the excitation singlet state energy and excitation triplet state energy of the material used as the blocking layer is higher than the excitation singlet state energy and excitation triplet state energy of the light-emitting layer, respectively.

[0147] (Hole transport layer) The so-called hole transport layer contains hole transport material with the function of transporting holes. The hole transport layer can be set in a single layer or multiple layers.

[0148] The hole transport material is a material that possesses either hole injection or transport or electron barrier properties, and can be either organic or inorganic. Examples of known hole transport materials that can be used include: triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolineone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrene-anthracene derivatives, fumonisin derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymeric oligomers, particularly thiophene oligomers. Porphyrin compounds, aromatic tertiary amine compounds, and styrene-based amine compounds are preferred, and aromatic tertiary amine compounds are even more preferred.

[0149] (Electron transport layer) The so-called electron transport layer contains materials that have the function of transporting electrons. The electron transport layer can be a single layer or multiple layers.

[0150] As an electron transport material (and sometimes also a hole blocking material), it is sufficient to have the function of transferring electrons injected from the cathode to the light-emitting layer. Examples of usable electron transport layers include: nitro-substituted piracetam derivatives, diphenylquinone derivatives, thiamethane dioxide derivatives, carbodiimide, piracetamethane derivatives, anthraquinone dimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, among the oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is replaced with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group, can also be used as electron transport materials. Furthermore, polymer materials incorporating these materials into polymer chains or using these materials as the backbone of polymers can also be used.

[0151] When fabricating organic electroluminescent devices, compounds represented by general formula (1) can be used not only in the light-emitting layer but also in layers other than the light-emitting layer. In this case, the compound represented by general formula (1) used in the light-emitting layer and the compound represented by general formula (1) used in layers other than the light-emitting layer may be the same or different. For example, compounds represented by general formula (1) can also be used in the injection layer, blocking layer, hole blocking layer, electron blocking layer, exciton blocking layer, hole transport layer, electron transport layer, etc. There are no particular limitations on the film-forming method of these layers, and they can be fabricated by either a dry process or a wet process.

[0152] Hereinafter, preferred materials that can be used in organic electroluminescent devices are specifically illustrated. However, the materials that can be used in this embodiment are not limited to the illustrated compounds described below. Furthermore, even compounds illustrated as materials with specific functions can be used as materials with other functions. In the structural formulas of the illustrated compounds, R, R2 to R7 independently represent hydrogen atoms or substituents, and n represents an integer from 3 to 5.

[0153] The following shows preferred examples of compounds that can be used as the host material of the light-emitting layer.

[0154] [Transformation 35][Transformation 36][Transformation 37][Transformation 38]

[0155] The following are preferred examples of compounds that can be used as hole injection materials.

[0156] [Chemistry 39]

[0157] The following are preferred examples of compounds that can be used as hole transport materials.

[0158] [Transformation 40][Transformation 41][Transformation 42][Transformation 43][Transformation 44]

[0159] The following are preferred examples of compounds that can be used as electron blocking materials.

[0160] [Chemistry 45]

[0161] The following are preferred examples of compounds that can be used as hole-blocking materials.

[0162] [Transformation 46][Transformation 47]

[0163] The following are preferred examples of compounds that can be used as electron transport materials.

[0164] [Transformation 48][Transformation 49][Transformation 50][Transformation 51]

[0165] The following are preferred examples of compounds that can be used as electron injection materials.

[0166] [Chemistry 52]

[0167] The following are examples of compounds that are preferred as additives. For example, the compound can be added as a stabilizing material.

[0168] [Chemistry 53]

[0169] The organic electroluminescent device fabricated by the method emits light by applying an electric field between the anode and cathode of the obtained device. In this case, if the emission is based on the excitation singlet state energy, the light of the wavelength corresponding to that energy level is identified as fluorescence and delayed fluorescence. Furthermore, if the emission is based on the excitation triplet state energy, the light of the wavelength corresponding to that energy level is identified as phosphorescence. Since the fluorescence lifetime of ordinary fluorescence is shorter than that of delayed fluorescence, the emission lifetime can be distinguished according to fluorescence and delayed fluorescence.

[0170] On the other hand, regarding phosphorescence, in ordinary organic compounds like those in this embodiment, the excited triplet energy is unstable and converts to heat, has a short lifetime, and is immediately deactivated, so it is almost unobservable at room temperature. In order to determine the excited triplet energy of ordinary organic compounds, it can be determined by observing the luminescence under extremely low temperature conditions.

[0171] The organic electroluminescent element of this embodiment can also be applied to any of the following: a single element, an element comprising an array-like structure, or an element comprising an anode and a cathode arranged in an XY matrix.

[0172] According to this embodiment, by containing a compound represented by general formula (1) in the light-emitting layer, an organic light-emitting element with significantly improved luminous efficiency in the NIR region can be obtained. The organic light-emitting element of this embodiment, and other organic light-emitting elements, can then be applied to various applications. For example, an organic electroluminescent display device can be manufactured using the organic electroluminescent element of this embodiment; for details, please refer to "Organic EL Display" (Ohmsha) co-authored by Shizuo Tokito, Chinatsuya Adachi, and Hideyuki Murata. In particular, the organic electroluminescent element of this embodiment can also be applied to bioimaging, medical cameras, sensors, surveillance cameras, night vision displays, and information protection displays.

[0173] The compounds represented by general formula (1) exhibit high fluorescence quantum yield and improved NIR luminescence properties. These can be used in solution, particularly in organic solvents, and in the solid state.

[0174] Compounds represented by general formulas (1), (4), (5), and (6) are effective as sensors for volatile acids / bases in bioimaging, particularly cell imaging; as optical sensors for anaerobic environments in photodynamic therapy, the diagnosis of Alzheimer's disease, and therapeutic diagnostics; and as light emitters in organic semiconductor lasers, particularly in solar cells as electron donors, in displays and electrical communication technologies. These compounds can exhibit fluorescence reporting of human β-amyloid peptides produced in nerve tissue and blood during the course of Alzheimer's disease, and therefore can be used for the diagnosis of Alzheimer's disease.

[0175] In addition, this embodiment provides an organic semiconductor laser containing a compound represented by general formula (1). The compound of general formula (1) is effectively used as a material in the light-emitting layer (light amplification layer) of the organic semiconductor laser.

[0176] The luminescent layer may contain two or more compounds of general formula (1), preferably containing only one compound of general formula (1). The luminescent layer may contain a host material. The host material preferably has sufficient spectral overlap between its fluorescence spectrum and the absorption spectrum of the compound of general formula (1) contained in the luminescent layer, resulting in an effective Forster-type energy transfer from the host material to the compound of general formula (1). Examples of preferred host materials are the same as those exemplified by chemical formulas as "preferred examples of compounds that can be used as host materials of the luminescent layer". Regarding the concentration of the compound of general formula (1) in the luminescent layer, it is preferably contained in an amount of 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more in 100% by mass of the luminescent layer. The upper limit of the concentration of the compound of general formula (1) is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 10% by mass or less. The lower and upper limits can be combined arbitrarily.

[0177] The organic semiconductor laser of this embodiment has an optical resonator structure. The optical resonator structure can be a one-dimensional resonator structure or a two-dimensional resonator structure. Examples of two-dimensional resonator structures include: circulator resonator structures, whispering gallery type optical resonator structures, etc. In addition, distributed feedback (DFB) structures and distributed Bragg reflector (DBR) structures can also be used. Regarding DFB, a hybrid-order DFB lattice structure is preferred. That is, a hybrid structure that uses a DFB grating structure that is different in order relative to the laser emission wavelength is preferred.

[0178] As a specific example, an optical resonator structure comprising a secondary Bragg scattering region surrounded by a primary Bragg scattering region, and a hybrid structure in which secondary Bragg scattering regions and primary scattering regions are alternately formed, can be cited. For details regarding preferred optical resonator structures, refer to the specific examples described later. As an optical resonator structure, an organic semiconductor laser may further include an optical resonator structure externally. For example, the optical resonator structure is preferably formed on a glass substrate. As a material constituting the optical resonator structure, insulating materials such as SiO2 can be cited. For example, in the case of forming a grating structure, the depth of the grating is preferably 75 nm or less, and more preferably selected from the range of 10 nm to 75 nm. The depth may be, for example, 40 nm or more, or less than 40 nm. A light-emitting layer (light amplification layer) containing a compound of general formula (1) may be directly formed on the optical resonator structure.

[0179] Organic semiconductor lasers are preferably encapsulated in sapphire or other materials to reduce the oscillation threshold and optimize heat dissipation under strong optical pumping. An interlayer may be formed between the sapphire cap and the light-emitting layer. For example, it is preferable to use an amorphous fluorinated polymer such as CYTOP (registered trademark) as the interlayer.

[0180] The embodiments of the present invention have been described above, but these are merely examples. Various structures other than those described may be used without impairing the effects of the present invention. [Examples]

[0181] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. (Synthesis Example 1) Synthesis of Compound 2 [Chemical 54]

[0182] Tetra(triphenylphosphine)palladium(O) (0.270 g, 0.234 mmol) was added to a mixed solution of 4-[N,N-bis(bromophenyl)amino]benzaldehyde (2.53 g, 5.87 mmol), 4-isopropoxyphenylboronic acid (2.74 g, 15.2 mmol), and potassium carbonate (4.19 g, 30.3 mmol) in toluene (90 mL) and water (30 mL). The mixture was heated under nitrogen and refluxed for 2.5 hours. The reaction solution was then diluted with toluene and washed with saturated brine. The aqueous layer was extracted twice with dichloromethane, and the combined organic layers were dried with magnesium sulfate, filtered, and concentrated. The residue was purified using a silicone column (chloroform-dichloromethane) to obtain intermediate 1 (2.90 g, 91%), a yellow solid represented by the following formula. [Chemical 55]

[0183] mp 60℃; 1H-Nuclear Magnetic Resonance (1H-NMR) (400 MHz, CDCl₃) δ (ppm) 1.36 (s, 6H), 1.38 (s, 6H), 4.55-4.65 (m, 2H), 6.96 (d, 4H, J=8.8Hz), 7.11 (d, 2H, J=8.8Hz), 7.24 (d, 4H, J=8.5Hz), 7.48-7.56 (m, 8H), 7.71 (d, 2H, J=8.8Hz).

[0184] A suspension of potassium trifluoro(trifluoromethyl)borate (0.368 g, 2.09 mmol) in acetonitrile (10 mL) was added dropwise to a solution cooled to 0°C in an ice bath. The mixture was stirred at 0°C under nitrogen for 0.5 hours. Subsequently, 3-phenyl-2,4-pentanedione (0.185 g, 1.05 mmol) was added to the reaction solution, and the mixture was heated to room temperature and stirred under nitrogen for three nights. Then, a solution of 4-[bis(4'-isopropoxy-[1,1'-biphenyl]-4-yl)amino]benzaldehyde (intermediate 1) (1.16 g, 2.14 mmol) and tributyl borate (0.68 mL, 2.54 mmol) in ethyl acetate (30 mL) was added to the reaction solution, and the mixture was stirred at 40°C under nitrogen for 0.5 hours. Morpholine (0.223 mL, 2.56 mmol) was added to the reaction solution, and the mixture was stirred at 70 °C under nitrogen for 7 hours. Morpholine (0.045 mL, 0.52 mmol) was then added to the reaction solution, and the mixture was stirred at 70 °C under nitrogen for 1.5 hours. After the reaction solution was brought to room temperature, it was concentrated, and the residue was purified using a silicone column (dichloromethane-toluene). The obtained solid was then suspended and washed with hexane to obtain a dark blue solid, compound 2 (0.489 g, 35%), represented by the stated formula.

[0185] mp264℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 1.36 (s, 12H), 1.38 (s, 12H), 4.54-4.65 (m, 4H), 6.32 (d, 2H, J=15.1Hz), 6.92-7.00 (m, 12H), 7.18 (d, 8H, J=8.5Hz), 7.27-7.32 (m, 6H), 7.42-7.53 (m, 19H), 7.98 (d, 2H, J=15.1Hz); Low Resolution Mass Spectrometry (LRMS) (FD): m / z calcd for C86H77BF4N2O6+ (calculated value of C86H77BF4N2O6+): 1320.6 [M]+; found (test value) 1320.6.

[0186] (Synthetic Example 2) Synthesis of Compound 1 [Chemical 56]

[0187] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.493 g, 2.80 mmol), trimethylsilyl trifluoromethanesulfonate (0.52 mL, 2.88 mmol), 3-phenyl-2,4-pentanedione (0.269 g, 1.53 mmol), 4-(N,N-diphenylamino)benzaldehyde (0.809 g, 2.96 mmol), tributyl borate (0.94 mL, 3.51 mmol), and morpholine (0.372 mL, 4.26 mmol) were used to obtain compound 1 (0.466 g, 39%), a dark blue solid, by the same method as the synthesis of compound 2 in Synthetic Example 1.

[0188] mp271℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 6.30 (d, 2H, J=15.1Hz), 6.88 (d, 4H, J=8.8Hz), 7.09-7.16 (m, 12H), 7.21-7.25 (m, 4H), 7.27-7.33 (m, 10H), 7.41-7.48 (m, 3H), 7.96 (d, 2H, J=15.4Hz); LRMS (FD): m / z calcd for C50H37BF4N2O2+: 784.3[M]+; found 784.3.

[0189] (Synthetic Example 3) Synthesis of Compound 3 [Chemical 57]

[0190] As raw materials and reaction reagents, potassium trifluoro(pentafluoroethyl)borate (0.470 g, 2.08 mmol), trimethylsilyl trifluoromethanesulfonate (0.38 mL, 2.10 mmol), 3-phenyl-2,4-pentanedione (0.190 g, 1.08 mmol), 4-(N,N-diphenylamino)benzaldehyde (0.593 g, 2.17 mmol), tributyl borate (0.68 mL, 2.54 mmol), and morpholine (0.266 mL, 3.06 mmol) were used to obtain compound 3 (0.693 g, 77%), a dark blue solid, by the same method as the synthesis of compound 2 in Synthetic Example 1.

[0191] mp242℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 6.30 (d, 2H, J=15.1Hz), 6.88 (d, 4H, J=8.8Hz), 7.09-7.16 (m, 12H), 7.23 (d, 4H, J=9.0Hz), 7.26-7.33 (m, 10H), 7.41-7.48 (m, 3H), 7.93 (d, 2H, J=15.1Hz); LRMS (FD): m / z calcd for C51H37BF6N2O2+: 834.3[M]+; found 834.3.

[0192] (Synthetic Example 4) Synthesis of Compound 4 [Chemical 58]

[0193] A solution of 0.2439 g (1.38 mmol) of 3-phenyl-2,4-pentanedione in 10 mL of dichloromethane was added to a fluorobis(pentafluorophenyl)borane diethyl ether complex (2.3356 g, 5.332 mmol), and the mixture was stirred for two nights at room temperature under nitrogen atmosphere. The reaction solution was concentrated and the residue was passed through a silicone column (hexane-ethyl acetate) to obtain intermediate 2 as a crude product, represented by the following formula. [Chem. 59]

[0194] A solution of 4-(N,N-diphenylamino)benzaldehyde (0.692 g, 2.53 mmol) and tributyl borate (0.8 mL, 2.99 mmol) in ethyl acetate (25 mL) was added to an ethyl acetate (4 mL) solution of intermediate 2. Then, morpholine (0.105 mL, 1.2 mmol) was added to the reaction solution, and the mixture was heated under reflux for 4.5 hours under nitrogen. After the reaction solution was brought to room temperature, it was concentrated, and the residue was purified using a silicone column (dichloromethane). The obtained solid was then suspended and washed with methanol to obtain a dark blue solid representing compound 4 (1.08 g, 87%).

[0195] mp277℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 6.36 (d, 2H, J=15.2Hz), 7.10-7.14 (m, 12H), 7.20-7.22 (m, 2H), 7.25-7.31 (m, 10H), 7.41-7.43 (m, 3H), 7.96 (d, 2H, J=15.2Hz); LRMS (FD): m / z calcd for C61H37BF10N2O2+: 1030.3[M]+; found 1030.3.

[0196] (Synthetic Example 5) Synthesis of Compound 5 [Chemical 60]

[0197] Using 4-[N,N-bis(bromophenyl)amino]benzaldehyde (3.06 g, 7.11 mmol), 4-trimethylsilylphenylboronic acid (3.52 g, 18.1 mmol), tetrakis(triphenylphosphine)palladium(O) (0.333 g, 0.288 mmol), and potassium carbonate (5.65 g, 40.9 mmol) as raw materials and reaction reagents, intermediate 3 (3.77 g, 93%), a yellow solid, was obtained by the same method as that used in the synthesis of intermediate 1 in Synthetic Example 1. [Chemical 61]

[0198] mp92℃; 1H-NMR (270 MHz, CDCl 3) δ (ppm) 0.31 (s, 18H), 7.15 (d, 2H, J=8.6Hz), 7.23?7.30 (m, 6H), 7.55?7.64 (m, 12H) 7.73 (d, 2H, J=8.9Hz), 9.84 (s, 1H).

[0199] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.338 g, 1.92 mmol), trimethylsilyl trifluoromethanesulfonate (0.36 mL, 1.99 mmol), 3-phenyl-2,4-pentanedione (0.174 g, 0.987 mmol), intermediate 3 (1.13 g, 1.99 mmol), tributyl borate (0.64 mL, 2.39 mmol), and morpholine (0.21 mL, 2.41 mmol) were used to obtain compound 5 (0.398 g, 29%), a dark blue solid, represented by the formula described above, by the same method as the synthesis of compound 2 in Synthetic Example 1.

[0200] mp207℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 0.30 (s, 36H) 6.34 (d, 2H, J=15.4Hz), 7.01 (d, 4H, J=9.3Hz), 7.22 (dd, 12H, J=4.1, 9.3Hz), 7.28?7.32 (m, 6H), 7.43?7.49 (m, 3H), 7.52?7.62 (m, 3H), 7.99 (d, 2H, J=15.4Hz); LRMS (FD): m / z calcd for C 86H 85BF 4N 2O 2Si 4 +:1377.6[M] +;found 1377.6.

[0201] (Synthetic Example 6) Synthesis of Compound 6 [Chemical 62]

[0202] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.539 g, 3.15 mmol), trimethylsilyl trifluoromethanesulfonate (0.58 mL, 3.20 mmol), 3-phenyl-2,4-pentanedione (0.282 g, 1.60 mmol), 4-[bis(4-(tert-butyl)phenyl)amino]benzaldehyde (1.23 g, 3.19 mmol), tributyl borate (1.03 mL, 3.85 mmol), and morpholine (0.746 mL, 8.55 mmol) were used to obtain compound 6 (0.649 g, 40%), a dark blue solid, by the same method as that used in the synthesis of compound 2 in Synthetic Example 1.

[0203] mp Decomp.; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 1.31 (s, 36H), 6.26 (d, 2H, J=15.4Hz), 6.83 (d, 4H, J=9.0Hz), 7.02?7.07 (m, 8H), 7.21 (d, found 1008.6.

[0204] (Synthetic Example 7) Synthesis of Compound 7 [Chemical 63]

[0205] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.367 g, 2.09 mmol), trimethylsilyl trifluoromethanesulfonate (0.4 mL, 2.21 mmol), methyl-4-(3'-acetylacetone)benzoate (0.261 g, 1.11 mmol), intermediate 1 (1.22 g, 2.25 mmol), tributyl borate (0.72 mL, 2.69 mmol), and morpholine (0.232 mL, 2.67 mmol) were used to obtain compound 7 (0.439 g, 29%), a dark blue solid, by the same method as the synthesis of compound 2 in Synthetic Example 1.

[0206] mp273℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 1.36 (s, 12H), 1.38 (s, 12H), 3.94 (s, 3H), 4.53?4.62 (m, 4H), 6.24 (d, 2H, J=15.1Hz), 6.92?7.00 (m, 12H), 7.19 (d, 8H, J=8.5Hz), 7.23?7.29 (m, 4H), 7.41 (d, 2H, J=8.3Hz), 7.46?7.52 (m, 16H), 8.00 (d, 2H, J=15.1Hz), 8.14 (d, 2H, J=8.3Hz); LRMS (FD): m / z calcd for C 88H 79BF 4N 2O 8 +: 1378.6[M] +; found 1378.6.

[0207] (Synthetic Example 8) Synthesis of Compound 8 [Chemical 64]

[0208] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.522 g, 2.97 mmol), trimethylsilyl trifluoromethanesulfonate (0.54 mL, 2.99 mmol), 3-phenyl-2,4-pentanedione (0.261 g, 1.48 mmol), 5-[4-(bis(4-tert-butylphenyl)amino)phenyl]thiophene-2-carboxaldehyde (1.45 g, 3.10 mmol), tributyl borate (0.99 mL, 3.70 mmol), and morpholine (0.372 mL, 4.28 mmol) were used to obtain compound 8 (0.606 g, 35%), a dark blue solid, by the same method as the synthesis of compound 2 in Synthetic Example 1.

[0209] mp209℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 1.32 (s, 36H), 6.16 (d, 2H, J=14.9Hz), 6.97 (d, 4H, J=8.8Hz), 7.02?7.06 (m, 8H), 7.17 (d, 2H, J=4.1Hz), 7.26?7.33 (m, 12H), 7.39 (dd, 4H, J=4.9, 8.8Hz), 7.48?7.53 (m, 3H), 8.09 (d, 2H, J=15.1Hz); LRMS (FD): m / z calcd for C 74H 73BF 4N 2O 2S 2 +: 1172.5[M] +; found 1172.5.

[0210] (Synthetic Example 9) Synthesis of Compound 9 [Chemical 65]

[0211] As raw materials and reaction reagents, potassium trifluoro(trifluoromethyl)borate (0.600 g, 3.41 mmol), trimethylsilyl trifluoromethanesulfonate (0.62 mL, 3.43 mmol), 3-phenyl-2,4-pentanedione (0.315 g, 1.79 mmol), 5-(diphenylamino)thiophene-2-carboxaldehyde (0.996 g, 3.57 mmol), tributyl borate (1.14 mL, 4.26 mmol), and morpholine (0.43 mL, 4.94 mmol) were used to obtain compound 9 (0.573 g, 40%), a dark blue solid, represented by the formula, by the same method as the synthesis of compound 2 in Synthetic Example 1. mp287℃; 1H-NMR (400 MHz, CDCl 3) δ (ppm) 5.72 (d, 2H, J=14.9Hz), 6.34 (d, 2H, J=4.4Hz), 7.12 (d, 2H, J=4.1Hz), 7.15?7.22 (m, 14H), 7.30?7.39 (m, 11H), 7.41?7.48 (m, 3H), 7.97 (d, 2H, J=14.6Hz); LRMS (FD): m / z calcd for C 46H 33BF 4N 2O 2S 2 +: 796.2[M] +; found 796.2.

[0212] (Synthetic Example 10) Synthesis of Compound 10 [Chemistry 66]

[0213] In a 50 mL flask, a mixture of 228 μL (1.463 mmol, 1 equivalent) of diacetyl ethyl acetate and 199 μL (1.609 mmol, 1.1 equivalent) of BF3·Et2O in 3 mL of ethyl acetate was heated in air at 50°C–60°C for 30 minutes. 4-(N,N-diphenylamino)-benzaldehyde (1 g, 3.658 mmol, 2.5 equivalent) and B(n-OBu)3 (0.987 mL, 3.658 mmol, 2.5 equivalent) were dissolved in 12 mL of ethyl acetate, and the solution was then added to the initial mixture. The reaction was continued at 50°C–60°C for 30 minutes. The first portion of BuNH2 (58 μL, 0.585 mmol, 0.4 equivalent) was added dropwise to the reaction product. After heating for 6 hours, the second portion of BuNH₂ (29 μL, 0.293 mmol, 0.2 equivalents) was added, and the reaction product was heated overnight at 50°C–60°C. All solvent was evaporated. A crude product consisting of trace amounts of the ligand and aldehyde was obtained by flash column chromatography (silicon dioxide, CH₂Cl₂). Further purification was performed by precipitation twice in CH₂Cl₂ / petroleum ether to obtain compound 10 (730 mg, 68% yield) as a dark green powder.

[0214] ¹H-NMR (400 MHz, CDCl₃, ppm): δ 8.10 (d, 1J=15.1Hz, 2H), 7.45 (d, 1J=8.8Hz, 4H), 7.34 (m, 8H), 7.17 (m, 14H), 6.97 (d, 1J=8.7Hz, 4H), 4.40 (m, 2H), 1.42 (t, 1J=7.4Hz, 3H). High Resolution Mass Spectrometry (HRMS) (ESI+) [M+Na]+ calcd for C₄₆H₃₇N₂O₄BF₂Na⁺ m / z=753.2712, found m / z=753.2716.

[0215] (Absorption, luminescence) (Example 1) Solution: A solution was prepared by dissolving compound 1 in the following solvent (concentration: 10⁻⁵ mol / L): Dichloromethane (DCM), Toluene (Tol).

[0216] The solution was irradiated with light at room temperature, and luminescence was observed. Figures 1 and 2 show the normalized electron absorption and luminescence (PL) spectra of the DCM and Tol solutions of compound 1, respectively. The absorption wavelength λabs (nm), luminescence (PL) wavelength λem (nm), Stokes shift ΔνST (cm⁻¹), and quantum yield Φf (%) are shown in Table 1. The absorption spectra were measured using a LAMBMA950 UV-Vis spectrophotometer (manufactured by Perkin Elmer Japan Co., Ltd.), the luminescence (PL) spectra were measured using a FP-8600 spectrophotometer (manufactured by Japan Spectrophotometer Co., Ltd.), and the quantum yield was measured using an absolute PL quantum yield measuring device (manufactured by Hamamatsu Photonics Co., Ltd.).

[0217] [Table 1] Table 1 Compound 1 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 634 767 2735 7 Tol 625 685 1400 50

[0218] Solutions of compounds 2, 3, and 5–9 were prepared in the same manner, and their absorption and luminescence were observed. The absorption wavelength λabs (nm), luminescence (PL) wavelength λem (nm), Stokes shift ΔνST (cm⁻¹), and quantum yield Φf (%) of the solutions of compounds 2, 3, and 5–9 are shown in Tables 2–8, respectively.

[0219] [Table 2] Table 2 Compound 2 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 658 775 2294 0.2 Tol 651 717 1414 45

[0220] [Table 3] Table 3 Compound 3 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 634 754 2510 12 Tol 627 684 1329 77

[0221] [Table 4] Table 4 Compound 5 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 651 802 2892 2 Tol 642 707 1432 71

[0222] [Table 5] Table 5 Compound 6 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 654 788 2600 2 Tol 641 707 1456 71

[0223] [Table 6] Table 6 Compound 7 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 668 ND ND <1 Tol 659 739 1643 60 ND: Not Detected

[0224] [Table 7] Table 7 Compound 8 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 695 ND ND <1 Tol 690 782 1360 70 ND: Not Detected

[0225] [Table 8] Table 8 Compound 9 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 703 782 1437 32 Tol 685 729 881 90

[0226] In the solution spectra of compounds 1-3 and compounds 5-9, a tendency for longer peak wavelengths was observed in DCM, a highly polar solvent, compared to Tol, a low-polarity solvent, and a darkening effect due to the polarity of the solvent was also observed. This result indicates that the curcumin compounds possess charge-transfer properties. This behavior is related to the strong electron-withdrawing properties of the central halogen and alkyl boron halide sites, and the strong electron-donating properties of the triphenylamine sites at both ends.

[0227] (Comparative Example 1) For compound 10, a solution was prepared in the same manner as in Example 1. The normalized electronic absorption and emission (PL) spectra of the DCM solution and the Tol solution are shown in Figures 3 and 4. In addition, the absorption wavelength λabs (nm), emission (PL) wavelength λem (nm), Stokes shift ΔνST (cm⁻¹), and quantum yield Φf (%) are shown in Table 9.

[0228] [Table 9] Table 9 Compound 10 solvent λ abs (nm) λ em (nm) Δ νST (cm) -1 ) Φ f (%) DCM 611 752 3069 6 Tol 591 654 1630 90

[0229] Compound 10, like compounds 1-3 and 5-9, exhibited a dark color effect due to the solvent, indicating charge transfer properties. Compared to compounds 1-3 and 5-9, compound 10 showed shorter absorption and luminescence (PL) wavelengths in toluene or dichloromethane solutions. This is believed to be because the boron-bonded alkyl halides in compounds 1-3 and 5-9 have stronger electron-withdrawing properties than fluorine.

[0230] (Example 2) A thin film was formed by spin-coating a solution of 82 μL of a chloroform solution of 5 mg / mL Compound 1 and 338 μL of a chloroform solution of 35 mg / mL 4,4'-bis(N-carbazolyl)-1,10-biphenyl (CBP)) onto a pre-cleaned quartz substrate to form a thin film with a thickness of 200 nm. The concentration of Compound 1 in the thin film was 3% by weight. The thin film was irradiated with light at room temperature, and luminescence was observed. Figure 5 shows the normalized electron absorption and luminescence (PL) spectra of the thin film of Compound 1. The absorption wavelength λabs (nm), the luminescence (PL) wavelength λem (nm), and the photoluminescence quantum yield PLQY (Φf) (%) are shown in Table 10. Absorption spectra were measured using a UV-Vis spectrophotometer LAMBMA950 (manufactured by Perkin Elmer Japan Co., Ltd.), luminescence (PL) spectra were measured using a spectrofluorescence spectrophotometer FP-8600 (manufactured by Japan Spectrophotometer Co., Ltd.), and quantum yield was measured using an absolute PL quantum yield measuring device (manufactured by Hamamatsu Photonics Co., Ltd.).

[0231] [Table 10] Table 10 Thin Films (3 wt%) Compound 1 λ abs (nm) λ em (nm) Φ f (%) Compound 1 649 713 55

[0232] Similarly, compounds 2 to 9 were determined. The results are summarized in Table 11.

[0233] [Table 11] Table 11 Thin Films (3 wt%) Compounds 2 to 9 λ abs (nm) λ em (nm) Φ f (%) Compound 2 680 748 twenty three Compound 3 658 727 53 Compound 4 640 716 59 Compound 5 666 754 42 Compound 6 664 750 37 Compound 7 690 773 11 Compound 8 717 797 8 Compound 9 715 770 7

[0234] The absorption peak wavelengths of compounds 1 to 9 correspond to the transition of charge from the base state (S0) to the first singlet excited state (S1). When compounds 1 to 9 were excited at 340 nm, the resulting emission (PL) peak wavelengths were 713 nm, 748 nm, 727 nm, 716 nm, 754 nm, 750 nm, 773 nm, 797 nm, and 770 nm, respectively, with PLQY values ​​of 55%, 23%, 53%, 59%, 42%, 37%, 11%, 8%, and 7%, respectively. Compared with compound 10 (Comparative Example 2, described later), compounds 1, 3, and 4 have the same degree of PLQY, and their emission (PL) peak wavelengths are long wavelengths. Compared with compound 10 (described later), compounds 2, 5-9 have lower PLQY, but their luminescence (PL) peak wavelengths are around 30 nm to 90 nm, which are long wavelengths. The longer the luminescence wavelength, the higher the linearity and the lower the invasiveness to organisms. Therefore, compounds 1-9 are superior to compound 10 in this respect.

[0235] (Comparative Example 2) Regarding compound 10, a thin film was prepared in the same manner as in Example 2. The concentration of compound 10 in the thin film was set to 3% by weight, and the results of measuring the normalized electron absorption and emission (PL) spectra of the thin film are shown in Figure 6. In addition, the absorption wavelength λabs (nm), emission (PL) wavelength λem (nm), and photoluminescence quantum yield PLQY (Φf) (%) are shown in Table 12.

[0236] [Table 12] Table 12 Thin Films (3 wt%) Compound 10 λ abs (nm) λ em (nm) Φ f (%) Compound 10 617 703 56

[0237] Compound 10 has an absorption peak wavelength of 617 nm, which corresponds to the migration of charge from the base state (S0) to the first singlet excited state (S1). When compound 10 is excited at 340 nm, the resulting emission (PL) peak wavelength is 703 nm, and the PLQY is 56%. Compared with compounds 1 to 9, compound 10 exhibits shorter absorption and emission (PL) wavelengths in the thin film. Furthermore, the PLQY of compound 10 is similar to that of compounds 1, 3, and 4.

[0238] (Example 3) ASE Properties: Using thin films of compounds 1 to 9 prepared in Example 2, their potential for organic semiconductor lasers was evaluated. The thin films were photoexcited by a 337 nm pulsed nitrogen laser NL100 (Stanford Research Systems), where the CBP host strongly absorbs light. The pump laser pulse width was approximately 3.5 ns, and its repetition frequency was 20 Hz. A set of attenuation filters was used to control the pump intensity. The pump laser beam was focused into 0.5 cm × 0.2 cm stripes. The emission (PL) spectrum from the end of the organic layer was measured using an optical fiber connected to a charge-coupled element spectrometer. The experimental structure is schematically shown in Figure 7. Emission was detected using a PMA-50 multichannel spectrometer (Hamamatsu Photonics, Inc.).

[0239] Figure 8 shows the emission spectra of the CBP:compound 1 (97 wt%: 3 wt%) doped film before and after the ASE threshold. Figure 9 shows the emission spectra of the 3 wt% compound 1 and CBP doped film measured at various pump intensities below and above the threshold. At low excitation intensities, the PL spectrum is broad and independent of the pump intensities. At high excitation intensities, ASE is generated, and a narrowing of the emission band spectrum is observed. Above the ASE threshold, the full width at half maximum (FWHM) of the sample decreases to 35 nm. This ASE effect is caused by naturally emitted photons, which are guided within the film and amplified by induced emission. In Figure 10, the output light intensity (left ordinate) and full width at half maximum (right ordinate) emitted from the end of the doped film are shown as a function of excitation intensity. The sharp change in ramp efficiency is directly related to the ASE threshold. In the case of a CBP:compound 1 (97 wt%: 3 wt%) doped film, the ASE threshold was determined to be approximately 0.3 μJ / cm². The ASE wavelength λASE (nm), full width at half maximum (FWHM) and ASE threshold Eth (μJ / cm²) of compound 1 are summarized in Table 13.

[0240] [Table 13] Table 13 Thin Films (3 wt%) Compound 1 λ ASE (nm) FWHM (nm) E th (μJ / cm) 2 ) Compound 1 782 35 0.3

[0241] This ASE threshold is also extremely low compared to the ASE threshold of compound 10 described later in Comparative Example 3. The wide range of emission (PL) spectra in the NIR region of compound 1, along with the measured ASE threshold, indicate great promise for the future realization of efficient and tunable organic semiconductor lasers. Similarly, the ASE characteristics of compounds 2 to 9 and compound 3 were measured. The results are summarized in Table 14.

[0242] [Table 14] Table 14 Thin Films (3 wt%) Compounds 2 to 9 λ ASE (nm) FWHM (nm) E th (μJ / cm) 2 ) Compound 2 831 35 2.6 Compound 3 778 30 0.6 Compound 4 764 27 1.7 Compound 5 804 17 2.6 Compound 6 803 19 1.7 Compound 7 851 twenty one 2.9 Compound 8 872 13 26.6 Compound 9 849 4 6.9

[0243] Compounds 2 to 9 can oscillate ASE at longer wavelengths than compound 10 (comparative example, described later), with compounds 2, 5 to 9 exhibiting ASE wavelengths exceeding 800 nm. Furthermore, compound 3, like compound 1, exhibits a very low ASE threshold, demonstrating its usefulness.

[0244] (Comparative Example 3) The ASE characteristics were evaluated using the Compound 10 film prepared in Comparative Example 2, in the same manner as in Example 3. Figure 11 shows the emission spectra of the CBP:Compound 10 (97 wt%: 3 wt%) doped film before and after the ASE threshold. Figure 12 shows the emission spectra of the 3 wt% Compound 10 and CBP doped film measured at various pump intensities below and above the threshold. When the ASE threshold is exceeded, the full half-maximum (FWHM) of the sample decreases to 35 m. In Figure 13, the output light intensity (left ordinate) emitted from the end of the doped film and the full half-maximum (right ordinate) are shown as a function of excitation intensity. The sharp change in ramp efficiency is directly related to the ASE threshold. In the case of the CBP:Compound 10 (97 wt%: 3 wt%) doped film, the ASE threshold was determined to be approximately 1.5 μJ / cm². The ASE wavelength λASE (nm), full width at half maximum (FWHM) (nm), and ASE threshold (E th) (μJ / cm 2) of compound 5 are summarized in Table 15.

[0245] [Table 15] Table 15 Thin Films (3 wt%) Compound 10 λ ASE (nm) FWHM (nm) E th (μJ / cm) 2 ) Compound 10 756 35 1.5

[0246] The ASE wavelength of compound 10 is 756 nm, which is shorter than that of compounds 1 to 9. This reflects the difference in emission (PL) wavelength observed in Example 2 and Comparative Example 2.

[0247] (Example 4) Distributed Feedback Laser (DFB Laser) (1) The DFB laser was manufactured by ultrasonic treatment using a neutral detergent, pure water, acetone, and isopropanol, followed by cleaning the glass substrate by UV-ozone treatment. A 100 nm thick SiO2 layer was sputtered onto the glass substrate to form a DFB lattice. The substrate was cleaned by ultrasonic treatment using isopropanol, followed by UV-ozone treatment. The SiO2 surface was treated with hexamethyl disilazane (HMDS) by spin-coating at 4,000 rpm for 15 seconds, and annealed at 120°C for 120 seconds. A resist layer of approximately 70 nm thickness was spin-coated onto the substrate using ZEP520A-7 solution (Zeon Corporation, Japan) at 4,000 rpm for 30 seconds, and baked at 180°C for 240 seconds. A lattice pattern was drawn on the resist layer using electron beam lithography on a JBX-5500SC system (JEOL). After electron beam irradiation, the pattern was developed at room temperature in a developer (ZEDN50, Zeon Corporation, Japan). The patterned resist layer was used as an etching mask, and the substrate was plasma etched using a FA-1EA etching system (SAMCO) and CHF 3. The lattice period (Λ) of the grating was selected based on the following Bragg condition: mλBragg=2neffΛm, where m is the diffraction order, λBragg is the Bragg wavelength, and neff is the effective refractive index of the gain medium. The DFB substrate was cleaned using conventional ultrasonic processing. A chloroform solution (concentration same as in Example 2) of compounds 1, 2, 5, and 4,4'-bis(N-carbazolyl)-1,10-biphenyl (CBP) (weight ratio, 3:97) was spin-coated onto a DFB substrate to form a light-emitting layer. A CYTOP polymer layer was then directly formed on the structure, and a sapphire cap with a thermal conductivity of 25 Wm⁻¹K⁻¹ was used to cover the structure at 300 K, creating a mixed-order DFB laser with a structure of glass / SiO₂ 2 / 3 wt% of compounds 1, 2, and 5: CBP / CYTOP / sapphire cap (Figure 14).

[0248] (2) Performance of DFB Lasers The performance of the manufactured DFB lasers was initially tested using a nitrogen laser with an excitation wavelength of 337 nm and a repetition rate of 20 Hz emitting 3.5 ns pulses in optical pumping. The emission spectrum measured perpendicularly to the surface of the organic DFB laser containing compound 1 is shown in Figure 15. At a grating lattice period (A2) of 550 nm, the emission wavelength of the DFB laser of compound 1 was 851 nm, showing a narrow half-peak full amplitude (FWHM) of about 0.1 nm. The emission intensity (left vertical axis) and the half-peak full amplitude (right vertical axis) as a function of excitation intensity are plotted in Figure 16. It was found that a significant change in the slope was observed as a signal of the laser oscillation threshold of 1.3 μJ / cm². The performance of the DFB lasers of compounds 2 and 5 were also evaluated in the same way. The diffraction lattice period (A2) (nm), DFB laser wavelength λDBB (nm), FWHM (nm), and laser oscillation threshold (E th) (μJ / cm 2) of the gratings used in compounds 1, 2, and 5 are summarized in Table 16. It is found that the wavelength and threshold of the DFB laser change depending on the grating period. The minimum laser oscillation threshold of compounds 1 and 5 is lower than the minimum threshold of compound 10 described later in Comparative Example 4. Furthermore, the wavelength at which the DFB laser reaches its minimum threshold is longer than that of compound 10, enabling oscillation in a longer wavelength NIR region. These DFB characteristics, combined with the ASE characteristics in Example 3, indicate the potential for realizing organic semiconductor lasers.

[0249] [Table 16] Table 16 DFB laser compounds 1, 2, and 5 Λ2 (nm) λ DFB (nm) FWHM (nm) E th (μJ / cm) 2 ) Compound 1 530 823 0.2 1.6 540 839 0.2 2.1 550 851 0.2 1.3 560 865 0.2 7.1 570 878 0.2 1.9 580 894 0.2 5.7 590 907 0.2 6.5 600 918 0.2 21.8 Compound 2 510 791 0.2 77.1 520 806 0.2 39.1 530 819 0.3 18.3 540 833 0.2 10.8 550 844 0.2 9.2 560 859 0.2 6.1 570 873 0.4 23.1 580 887 0.3 16.6 Compound 5 510 791 0.2 1.1 520 807 0.3 1.2 530 820 0.2 0.9 540 833 0.2 1.0 550 848 0.3 11.6 560 862 0.2 0.8

[0250] (Comparative Example 4) Compound 10 was used in the same manner as in Example 4 to prepare a DFB laser, and measurements were performed. Figure 17 shows the emission spectrum measured perpendicularly to the surface of the organic DFB laser containing Compound 10. Figure 18 shows a plot of the emission intensity (left vertical axis) and the full width at half maximum (FWHM) relative to the excitation intensity (right vertical axis). The diffraction lattice period (A2) (nm) of the grating used in Compound 10, the DFB laser wavelength λDFB (nm), the full width at half maximum (FWHM) (nm), and the laser oscillation threshold (E th) (μJ / cm 2) are summarized in Table 17.

[0251] [Table 17] Table 17 DFB Laser Compound 10 Λ2 (nm) λ DFB (nm) FWHM (nm) E th (μJ / cm) 2 ) Compound 10 510 789 0.2 3.1 520 807 0.2 2.1 530 820 0.2 1.5 540 832 0.2 2.0 550 846 0.2 5.9 560 857 0.2 7.7 570 875 0.2 37.3

[0252] The minimum threshold wavelength of compound 10's DFB laser is shorter compared to that of compounds 1, 2, and 5. This reflects the difference in ASE wavelength between the two compounds observed in Example 3 and Comparative Example 3.

[0253] This application claims priority based on Japanese Patent Application No. 2021-209006, filed on December 23, 2021, the entire contents of which are incorporated herein by reference. [Simplified Explanation of the Diagram]

[0010] Figure 1 is the normalized electron absorption and emission (PL) spectrum of compound 1 in dichloromethane (DCM) solution in Example 1. Figure 2 is the normalized electron absorption and emission (PL) spectrum of compound 1 in toluene (Tol) solution in Example 1. Figure 3 is the normalized electron absorption and emission (PL) spectrum of compound 10 in dichloromethane (DCM) solution in Comparative Example 1. Figure 4 is the normalized electron absorption and emission (PL) spectrum of compound 10 in toluene (Tol) solution in Comparative Example 1. Figure 5 is the normalized electron absorption and emission (PL) spectrum of thin film of compound 1 in Example 2. Figure 6 is the normalized electron absorption and emission (PL) spectrum of thin film of compound 10 in Comparative Example 2. Figure 7 is a structural diagram of the ASE characteristic evaluation test of thin films of compounds 1 to 9 in Example 3. Figure 8 is the emission spectrum before and after the ASE threshold of the CBP: compound 1 (97 wt%: 3 wt%) blended film in Example 3. Figure 9 is the emission spectrum of the 3 wt% compound 1 and CBP-doped film measured at various pump intensities below or above the threshold in Example 3. Figure 10 is a graph showing the output light intensity (left ordinate) and full-width at half maximum (HWHM) of the 3 wt% compound 1 and CBP-doped film as a function of excitation intensity in Example 3. Figure 11 is the emission spectrum of the CBP:compound 10 (97 wt%: 3 wt%)-doped film before and after the ASE threshold in Comparative Example 3. Figure 12 is the emission spectrum of the 3 wt% compound 10 and CBP-doped film measured at various pump intensities below or above the threshold in Comparative Example 3. Figure 13 is a graph showing the output light intensity (left ordinate) and full-width at half maximum (HWHM) of the 3 wt% compound 10 and CBP-doped film as a function of excitation intensity in Comparative Example 3. Figure 14 is a schematic cross-sectional view of the mixed-order DFB laser manufactured in Example 4. Figure 15 is the emission spectrum measured perpendicularly to the surface of the organic DFB laser containing compound 1 in Example 4. Figure 16 is a graph in Example 4 showing the emission intensity (left vertical axis) and the full width at half maximum (HWHM) value (right vertical axis) as a function of the excitation intensity of the organic DFB laser containing compound 1. Figure 17 is the emission spectrum measured perpendicularly to the surface of the organic DFB laser containing compound 10 in Comparative Example 4. Figure 18 is a graph in Comparative Example 4 showing the emission intensity (left vertical axis) and the full width at half maximum (HWHM) value (right vertical axis) as a function of the excitation intensity of the organic DFB laser containing compound 10. Figure 19 is a diagram showing a structural example of an organic electroluminescent element.

Claims

1. An organic electroluminescent element comprising a compound represented by general formula (1), wherein in general formula (1), X1 and X2 independently represent halogen atoms, alkyl halides or aryl halides, and at least one of X1 and X2 represents alkyl halides or aryl halides; R1 to R6 independently represent hydrogen atoms or substituents, and R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6, R6 and R7 may together represent a ring; R7 represents a group represented by general formula (2) or general formula (3) below; in general formula (2), Ar1 represents aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl or heteroaryl-substituted aryl, and R8 represents a substituent; multiple R8s may be the same or different, and at least one R8 is an electron-donating group; n8 represents an integer from 1 to Ar 1 that can be substituted. In general formula (3), R 9 to R 13 represent hydrogen atoms or substituents independently, and p represents an integer from 0 to 2.

2. The organic electroluminescent element as claimed in claim 1, wherein the compound represented by the general formula (1) is the compound represented by the following general formula (4), in which X1, X2, and R2 to R6 have the same meaning as in general formula (1); Ar2 and Ar3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl, or heteroaryl-substituted aryl; R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring; R14 and R15 independently represent substituents, and multiple R14s may be the same or different, at least one R14 is an electron-donating group, and multiple R15s may be the same or different, at least one R15 is an electron-donating group; n14 represents 1 to Ar The integers up to the numbers that can be substituted in Ar 2, and n15 represents the integers up to the numbers that can be substituted in Ar 3.

3. The organic electroluminescent element as claimed in claim 2, wherein in the general formula (4), at least one of R14 and R15 is a substituted or unsubstituted diarylamine group.

4. The organic electroluminescent element as claimed in claim 2, wherein in the general formula (4), Ar 2 and Ar 3 independently comprise a benzene structure, a naphthalene structure, an anthracene structure or a fusiform structure, respectively.

5. The organic electroluminescent element as claimed in claim 1, wherein the compound represented by the general formula (1) is the compound represented by the following general formula (5), in which X1, X2, and R2 to R6 have the same meaning as the general formula (1); Ar4 to Ar7 each independently represent a substituted or unsubstituted aryl group, and multiple Ar4 and Ar5 may be the same or different, and multiple Ar6 and Ar7 may be the same or different; R16 and R17 each independently represent a substituent other than a substituted or unsubstituted diarylamine group, and multiple R16 and R17 may be the same or different; R16 and R2, R3 and R4, R4 and R5, R6 and R17 may form a ring together; n16 and n18 each independently represent integers greater than or equal to 0 or 1, n17 and n19 each independently represent integers greater than or equal to 1, n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5.

6. The organic electroluminescent element as claimed in claim 1, wherein R4 is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryloxycarbonyl group, a halogen atom, or a group containing a boron difluoride diketone ring.

7. The organic electroluminescent element as claimed in claim 1, wherein R3 and R4, or R4 and R5 together form a ring.

8. The organic electroluminescent element as claimed in claim 1, wherein the compound represented by the general formula (1) is the compound represented by the following general formula (6), in which X1, X2, and R2 to R6 have the same meaning as in general formula (1); X1' and X2' represent halogen atoms, alkyl halides or aryl halides, and at least one of X1' and X2' represents alkyl halides or aryl halides; R2' to R6' each independently represent hydrogen atoms or substituents; R18 and R19 each independently represent one of the following group A, R18 and R2, R3 and R4, R4 and R5, R19 and R2', R3' and R4', and R4' and R5' can form a ring together, R6 can bond with A to form a ring, and R6' can bond with A to form a ring; A represents the linking group represented by the following general formula (7) or general formula (9); in general formula (7), n is an integer from 0 to 1 to 4, m is 0 or 1, A' represents an alkoxy group having 1 to 12 carbon atoms, and A'' represents the group represented by the following formula (8); in general formula (8), X 1'' and X 2'' represent halogen atoms, alkyl halides or aryl halides, at least one of X 1'' and X 2'' represents alkyl halides or aryl halides, R 2'' to R 6'' each independently represent hydrogen atoms or substituents, and R 20 represents one of the following group A; in the formula, R independently represents hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms, substituted or unsubstituted aryl groups having 6 to 10 carbon atoms, or substituted or unsubstituted heteroaryl groups, and in general formula (9), R 9 to R 12 and p have the same meaning as general formula (3).

9. The organic electroluminescent element as claimed in claim 1, wherein delayed fluorescence is emitted.

10. The organic electroluminescent element as claimed in claim 1, wherein it exhibits a maximum emission wavelength in the range of 700 nm to 1,500 nm.

11. An organic semiconductor laser comprising an organic electroluminescent element as described in any one of claims 1 to 10.

12. The organic semiconductor laser of claim 11, wherein the organic semiconductor laser has an optical resonator structure comprising a secondary Bragg scattering region surrounded by a primary Bragg scattering region.

13. A thin film having on a substrate a layer containing a compound represented by general formula (1) as claimed in claim 1, a compound represented by general formula (4) as claimed in claim 2, a compound represented by general formula (5) as claimed in claim 5, or a compound represented by general formula (6) as claimed in claim 8.

14. A compound represented by the following general formula (10), wherein X1, X2, and R2 to R6 have the same meaning as in general formula (1); Ar2 and Ar3 independently represent aryl, aryl-substituted aryl, heteroaryl-substituted aryl, aryl-heteroaryl, aryl-substituted aryl, or heteroaryl-substituted aryl; R3 and R4, R4 and R5 can form a ring together, R2 can bond with Ar2 to form a ring, and R6 can bond with Ar3 to form a ring; R14 and R15 independently represent substituents containing aryl, and multiple R14s may be the same or different, at least one R14 being an electron-donating group containing aryl, and multiple R15s may be the same or different, at least one R15 being an electron-donating group containing aryl; n14 represents 1 to Ar The integers up to the numbers that can be substituted in Ar 2, and n15 represents the integers up to the numbers that can be substituted in Ar 3.

15. The compound of claim 14, wherein in the general formula (10), at least one of R 14 and R 15 is a substituted or unsubstituted diarylamine group.

16. A compound represented by the following general formula (11), wherein X1, X2, and R2 to R6 have the same meaning as in the general formula (1); Ar4 to Ar7 each independently represent a substituted or unsubstituted aryl group, and multiple Ar6 and Ar7 may be the same or different, and multiple Ar4 and Ar5 may be the same or different; R16 and R17 each independently represent a substituent other than a substituted or unsubstituted diarylamine group, and multiple R16 and R17 may be the same or different; R16 and R2, R3 and R4, R4 and R5, R6 and R17 may form a ring together; n16 and n18 each independently represent integers greater than or equal to 0 or 1, n17 and n19 each independently represent integers greater than or equal to 1, n16+n17 is an integer from 1 to 5, and n18+n19 is an integer from 1 to 5.

17. A delayed phosphor comprising any one of claims 14 to 16.

18. An organic semiconductor laser comprising any one of claims 14 to 16.

19. The organic semiconductor laser of claim 18, wherein the organic semiconductor laser has an optical resonator structure comprising a secondary Bragg scattering region surrounded by a primary Bragg scattering region.

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