Polycyclic aromatic compound

Abstract

To provide a novel compound that is suitable as a material for organic devices including organic EL elements.SOLUTION: A polycyclic aromatic compound is represented by formula (1); wherein rings A, B, C, E, G, I, J, and K are each a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; Z is =C(-H) or the like; X1 and X2 are >N-RNX (where RNX is an aryl), >O, or >S; RNX in X1 may be bonded to ring C or ring d, and RNX in X2 may be bonded to ring h or ring I via a linking group or a single bond; rings A and B, rings B and C, rings E and G, rings I and J, and rings J and K may each be mutually bonded via a single bond or a linking group; and each element in formula (1) may be replaced with a heavy stable isotope.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polycyclic aromatic compound. The present invention also relates to organic devices such as organic electroluminescent elements, organic field-effect transistors, and organic thin-film solar cells, as well as display devices and lighting devices, which use the polycyclic aromatic compound. [Background technology]

[0002] Display devices using electroluminescent light-emitting elements have been the subject of extensive research because of their potential for power saving and thinning, and organic electroluminescent devices made from organic materials have also been actively investigated because they can be easily made lighter and larger. In particular, there has been active research into the development of organic materials that have the luminescence properties of blue and green, which are one of the three primary colors of light, and organic materials that have the ability to transport charges such as holes and electrons (potential to become semiconductors or superconductors), regardless of whether they are polymeric or low-molecular-weight compounds.

[0003] An organic EL device has a structure consisting of a pair of electrodes consisting of an anode and a cathode, and one or more layers containing organic compounds disposed between the pair of electrodes. The layers containing organic compounds include a light-emitting layer and a charge transport / injection layer that transports or injects charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

[0004] Among them, Patent Documents 1 to 3 disclose that boron-containing polycyclic aromatic compounds are useful as materials for organic electroluminescent devices, etc. It has been reported that organic electroluminescent devices containing these polycyclic aromatic compounds have good external quantum efficiency. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 102118 [Patent Document 2] International Publication No. 2018 / 212169 [Patent Document 3] International Publication No. 2022 / 034916 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, various materials have been developed for use in organic EL devices. However, in order to increase the options for materials for organic EL devices, it is desirable to develop materials made of compounds that are different from conventional ones. An object of the present invention is to provide a novel compound useful as a material for organic devices such as organic EL elements. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have discovered new polycyclic aromatic compounds that enable the production of highly efficient, long-life organic EL devices as compounds having a boron-containing structure similar to the compounds described in Patent Documents 1 to 3, thereby completing the present invention. That is, the present invention provides the following polycyclic aromatic compounds, as well as materials for organic devices containing the following polycyclic aromatic compounds.

[0008] <1> A polycyclic aromatic compound represented by formula (1); [ka] In formula (1), ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; Ring A and ring B may be bonded to each other via a single bond or a linking group; Ring B and ring C may be bonded to each other via a single bond or a linking group; ring E and ring G may be bonded to each other via a single bond or a linking group; Ring I and ring J may be bonded to each other via a single bond or a linking group; the ring J and the ring K may be bonded to each other via a single bond or a linking group; Each Z is independently =C(R Z )- or =N-, and R Z is hydrogen or a substituent, X 1 and X 2 are independently >NR NX ,>O,>C(-R CX )2, >Si(-R IX )2, >S, or >Se, and R NX is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; R CX and R IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; CX may be bonded to each other to form a ring, and two R IX may be bonded to each other to form a ring, and X 1 R in NX , R CX and R IX may be bonded to at least one of ring C and ring d via a linking group or a single bond, and X 2 R in NX , R CX and R IX may be bonded to at least one of ring h and ring I via a linking group or a single bond, At least one selected from the group consisting of aryl rings and heteroaryl rings in formula (1) may be fused with at least one cycloalkane, the cycloalkane may be substituted with at least one substituent, and at least one -CH2- in the cycloalkane may be replaced with -O-; At least one hydrogen in formula (1) may be replaced with deuterium, and at least one nitrogen may be replaced with nitrogen-15( 15 N), and at least one sulfur may be replaced by sulfur-33 (33 S), sulfur-34( 34 S) or sulfur-36( 36 S), at least one oxygen is oxygen-17( 17 O) or oxygen-18( 18 O), at least one carbon is carbon-13( 13 C), at least one boron is boron-11( 11 B) may be substituted.

[0009] <2> ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted aryl ring, a substituted or unsubstituted benzofuran ring, or a substituted or unsubstituted benzothiophene ring, and the benzofuran ring and the benzothiophene ring are each bonded to boron via a ring-constituting atom of a 5-membered ring; <1> The polycyclic aromatic compound according to any one of claims 1 to 4. <3> ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted benzene ring; <1> or <2> The polycyclic aromatic compound according to any one of claims 1 to 4. <4> X 1 and X 2 However, each independently >NR NX , >O, or >S, <1> ~ <3> 1. The polycyclic aromatic compound according to any one of claims 1 to 9.

[0010] <5> Satisfy at least one of (B-1) to (B-7), <1> ~ <4> The polycyclic aromatic compound according to any one of the preceding claims: (B-1)X 1 >NR NX and X 1 R in NX is attached to ring C or ring d via a single bond or a linking group; (B-2)X 2 >NR NX and X 2 R in NX is attached to ring I or ring h via a single bond or a linking group; (B-3) Ring A and ring B are bonded to each other via a single bond or a linking group; (B-4) Ring B and ring C are bonded to each other via a single bond or a linking group; (B-5) Ring E and ring G are bonded to each other via a single bond or a linking group; (B-6) Ring I and ring J are bonded to each other via a single bond or a linking group; (B-7) The J ring and the K ring are bonded to each other via a single bond or a linking group. <6> Contains a group represented by formula (1L) as a partial structure. <1> ~ <5> the polycyclic aromatic compound according to any one of the preceding claims; [ka] In formula (1L), * indicates the bond position, Ring L is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; R L is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted arylthio, a substituted or unsubstituted heteroarylthio, a substituted or unsubstituted aryloxy, a substituted or unsubstituted heteroaryloxy, a substituted alkyl, an unsubstituted alkyl having 3 to 24 carbon atoms, or a substituted or unsubstituted cycloalkyl.

[0011] <7> Represented by one of the following formulas <1> The polycyclic aromatic compound according to claim 1. [ka]

[0012] [ka]

[0013] <8> The organic layer is provided between a pair of electrodes consisting of an anode and a cathode, and the organic layer is <1> ~ <7> 10. An organic electroluminescent device comprising the polycyclic aromatic compound according to any one of claims 1 to 9. <9> the organic layer is an emitting layer; <8> The organic electroluminescent device according to claim 1. <10> the light-emitting layer contains a host material, a thermally activated delayed fluorescent material or a phosphorescent material as an assisting dopant, and the polycyclic aromatic compound as an emitting dopant; <9> The organic electroluminescent device according to claim 1. <11> <8> ~ <10> A display device or a lighting device comprising the organic electroluminescent device according to any one of the preceding claims. <12> <1> ~ <7> 1. A wavelength converting material comprising the polycyclic aromatic compound according to any one of claims 1 to 9. <13> <1> ~ <7> 10. An organic photodiode comprising the polycyclic aromatic compound according to any one of claims 1 to 9. [Effects of the Invention]

[0014] The present invention provides a novel polycyclic aromatic compound useful as a material for organic devices such as organic electroluminescent elements. The polycyclic aromatic compound of the present invention can be used in the production of organic devices such as organic electroluminescent elements. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view showing an example of an organic electroluminescent device. [Figure 2] FIG. 10 is a diagram showing the fluorescence spectrum of a thin film formed on a substrate in which compound (1-391) is dispersed in PMMA. [Figure 3] FIG. 1 is a diagram showing the fluorescence spectrum of a thin film formed on a substrate in which a compound (Ir(ppy)3) is dispersed in PMMA. [Figure 4] FIG. 10 is a diagram showing the fluorescence spectrum of a thin film formed on a substrate in which compound (R1-2) is dispersed in PMMA. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. The following explanation of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In addition, in this specification, "hydrogen" in the explanation of structural formulas means "hydrogen atom (H)". Similarly, "carbon atom (C)" may be referred to as "carbon". In this specification, the term "adjacent groups" refers to two groups bonded to two adjacent atoms (two atoms directly bonded by a covalent bond) in a structural formula.

[0017] In this specification, "Me" represents methyl, "Et" represents ethyl, "nBu" represents n-butyl (normal butyl), "tBu" represents t-butyl (tertiary butyl), "iBu" represents isobutyl, "secBu" represents secondary butyl, "nPr" represents n-propyl (normal propyl), "iPr" represents isopropyl, "tAm" represents t-amyl, "2EH" represents 2-ethylhexyl, "tOct" represents t-octyl, "Ph" represents phenyl, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Ad" represents 1-adamantyl, "Tf" represents trifluoromethanesulfonyl, "TMS" represents trimethylsilyl, and "D" represents deuterium. In this specification, the organic electroluminescent device may be referred to as an organic EL device.

[0018] In this specification, chemical structures and substituents are sometimes represented by the number of carbon atoms. However, when a chemical structure is substituted with a substituent or when a substituent is further substituted with a substituent, the number of carbon atoms refers to the number of carbon atoms in each of the chemical structure and the substituent, and does not refer to the total number of carbon atoms in the chemical structure and the substituent, or the total number of carbon atoms in the substituent and the substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent B of carbon number Y" is substituted with "substituent A of carbon number X," and the carbon number Y is not the total number of carbon atoms in substituents A and B. Also, for example, "substituent B of carbon number Y substituted with substituent A" means that "substituent B of carbon number Y" is substituted with "substituent A (with no carbon number restriction)," and the carbon number Y is not the total number of carbon atoms in substituents A and B.

[0019] <Explanation of rings and substituents> First, the rings and substituents used in this specification will be described in detail below. As used herein, the "aryl ring" includes, for example, an aryl ring having 6 to 30 carbon atoms, preferably an aryl ring having 6 to 16 carbon atoms, more preferably an aryl ring having 6 to 12 carbon atoms, and particularly preferably an aryl ring having 6 to 10 carbon atoms.

[0020] Specific examples of the "aryl ring" include a monocyclic benzene ring, a bicyclic bicyclic bicyclic naphthalene ring and an indene ring, a tricyclic terphenyl ring (m-terphenyl, o-terphenyl, p-terphenyl) and a fused tricyclic acenaphthylene ring, a fluorene ring, a phenalene ring, a phenanthrene ring, and an anthracene ring, fused tetracyclic triphenylene ring, a pyrene ring, a naphthacene ring, and a chrysene ring, fused pentacyclic perylene ring and a pentacene ring, etc. Furthermore, the fluorene ring, benzofluorene ring, and indene ring each include a structure in which a fluorene ring, a benzofluorene ring, a cyclopentane ring, etc. are spiro-bonded. The fluorene ring, benzofluorene ring, and indene ring also include rings in which two of the two hydrogen atoms of the methylene in the structure are replaced by alkyl such as methyl as the first substituent described below, resulting in a dimethylfluorene ring, dimethylbenzofluorene ring, dimethylindene ring, etc.

[0021] As used herein, examples of the "heteroaryl ring" include heteroaryl rings having 2 to 30 carbon atoms, preferably heteroaryl rings having 2 to 25 carbon atoms, more preferably heteroaryl rings having 2 to 20 carbon atoms, still more preferably heteroaryl rings having 2 to 15 carbon atoms, and particularly preferably heteroaryl rings having 2 to 10 carbon atoms. Furthermore, examples of the "heteroaryl ring" include heterocyclic rings containing, as ring-constituting atoms other than carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, boron, selenium, phosphorus, and tellurium.

[0022] Specific examples of the "heteroaryl ring" include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring (such as a furazan ring), a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, an isoindole ring, a 1H-indazole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, a 1H-benzotriazole ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinazoline ring, a quinoxaline ring, a phthalazine ring, a naphthyridine ring, a purine ring, a pteridine ring, a carbazole ring, an acridine ring, a phenoxathiin ring, a phenoxazine ring, a phenothiazine ring, a phenazine ring, a phenazasiline ring, an indolizine ring, a furan ring, a benzofuran ring, an isobenzofuran ring, a dibenzofuran ring, and a thiophene ring. , benzothiophene ring, dibenzothiophene ring, thianthrene ring, indolocarbazole ring, benzoindolocarbazole ring, dibenzoindolocarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, dibenzodioxin ring, dioxaboranaphthoanthracene ring (5,9-dioxa-13b-bora-13bH-naphtho[3,2,1-de]anthracene ring, etc.), benzoselenophen Examples of the dihydroacridine ring include a phenylene ring, a dibenzoselenophene ring, an azacarbazole ring, an azadibenzothiophene ring, an azadibenzofuran ring, an azadibenzoselenophene ring, an azatriphenylene ring, an imidazoimidazole ring, an indoloindole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, an indenocarbazole ring, a selenophenocarbazole ring, a spiro[fluorene-9,9'-xanthene] ring, a spirobi[silafluorene] ring, etc. In addition, dihydroacridine rings, xanthene rings, and thioxanthene rings are also preferred in which two of the two hydrogen atoms of the methylenes in the ring structure are each replaced by an alkyl such as methyl as the first substituent described below, thereby forming a dimethyldihydroacridine ring, a dimethylxanthene ring, a dimethylthioxanthene ring, etc.In addition, bicyclic rings such as bipyridine ring, phenylpyridine ring, and pyridylphenyl ring, and tricyclic rings such as terpyridyl ring, bispyridylphenyl ring, and pyridylbiphenyl ring are also included as "heteroaryl rings." Furthermore, "heteroaryl rings" also include pyran rings.

[0023] In this specification, a substituent may be substituted with an additional substituent. For example, a specific substituent may be described as "substituted or unsubstituted." This means that the specific substituent is substituted with at least one additional substituent, or is not substituted. In the same sense, the term "optionally substituted" may also be used. In this specification, the specific substituent may be referred to as a "first substituent," and the additional substituent may be referred to as a "second substituent."

[0024] In this specification, the substituent group Zα consists of the substituents of the substituent group Z and a substituent represented by the formula (A30) described below.

[0025] In the present specification, the substituent group Z is an aryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; heteroaryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; diarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen (two aryls may be bonded to each other via a linking group); diheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen (two heteroaryls may be bonded to each other via a linking group); arylheteroarylamino optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen (the aryl and heteroaryl may be bonded to each other via a linking group); diarylboryl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen (two aryls may be bonded via a single bond or a linking group); an alkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, cycloalkyl, cyano, and halogen; cycloalkyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; alkoxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, cycloalkyl, cyano, and halogen; aryloxy optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; an arylthio optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; alkenyl optionally substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano, and halogen; It consists of substituted silyl, cyano, and halogen. The aryl as the second substituent in each group of the substituent group Z may be further substituted with an aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen. Similarly, the heteroaryl as the second substituent may be substituted with an aryl, heteroaryl, alkyl, cycloalkyl, cyano, or halogen.

[0026] In this specification, when referring to a "substituent," the type of the substituent is not particularly limited, but unless otherwise specified, it may be any group selected from substituent group Z. For example, when a "substituted or unsubstituted" group is substituted, it may be substituted with at least one group selected from substituent group Z.

[0027] In this specification, "aryl" refers to, for example, aryl having 6 to 30 carbon atoms, and preferably aryl having 6 to 20 carbon atoms, aryl having 6 to 16 carbon atoms, aryl having 6 to 12 carbon atoms, or aryl having 6 to 10 carbon atoms.

[0028] Specific examples of "aryl" include monovalent groups obtained by removing one hydrogen atom from the above-mentioned "aryl ring." For example, the monocyclic ring system is phenyl, the bicyclic ring system is biphenylyl (2-biphenylyl, 3-biphenylyl, or 4-biphenylyl), the fused bicyclic ring system is naphthyl (1-naphthyl or 2-naphthyl), the tricyclic ring system is terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, or p-terphenyl-4-yl), the fused tricyclic ring system is acenaphthylene-(1-, 3-, 4-, or 5-), -)yl, fluoren-(1-, 2-, 3-, 4-, or 9-)yl, phenalen-(1- or 2-)yl, phenanthrene-(1-, 2-, 3-, 4-, or 9-)yl, or anthracene-(1-, 2-, or 9-)yl, the tetracyclic ring systems quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl fluorene-4-yl, m-quaterphenyl-4-yl, or m-quaterphenyl), fused tetracyclic ring systems such as triphenylene-(1- or 2-)yl, pyrene-(1-, 2-, or 4-)yl, or naphthacene-(1-, 2-, or 5-)yl, or fused pentacyclic ring systems such as perylene-(1-, 2-, or 3-)yl, or pentacene-(1-, 2-, 5-, or 6-)yl. Other examples include monovalent radicals of spirofluorene.

[0029] The aryl as the second substituent also includes a structure in which the aryl is substituted with at least one group selected from the group consisting of aryl such as phenyl (specific examples are the groups described above), alkyl such as methyl (specific examples are the groups described below), and cycloalkyl such as cyclohexyl or adamantyl (specific examples are the groups described below). An example of such a group is a group in which the 9-position of the fluorenyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl.

[0030] The "arylene" is, for example, an arylene having 6 to 30 carbon atoms, and preferably an arylene having 6 to 20 carbon atoms, an arylene having 6 to 16 carbon atoms, an arylene having 6 to 12 carbon atoms, or an arylene having 6 to 10 carbon atoms. Specific examples of "arylene" include divalent groups obtained by removing one hydrogen atom from the above-mentioned "aryl" (monovalent group).

[0031] The "heteroaryl" is, for example, a heteroaryl having 2 to 30 carbon atoms, and preferably a heteroaryl having 2 to 25 carbon atoms, a heteroaryl having 2 to 20 carbon atoms, a heteroaryl having 2 to 15 carbon atoms, or a heteroaryl having 2 to 10 carbon atoms. The "heteroaryl" contains, in addition to carbon, one or more, preferably 1 to 5, heteroatoms selected from oxygen, sulfur, nitrogen, etc. as ring-constituting atoms.

[0032] Specific examples of the "heteroaryl" include monovalent groups obtained by removing one hydrogen atom from the above-mentioned "heteroaryl ring." For example, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, Examples include acridinyl, phenoxathiinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenazasilinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, a monovalent group of a benzophosphole oxide ring, a monovalent group of a dibenzophosphole oxide ring, furazanyl, thianthrenyl, indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl, and oxazolinyl. Other examples include a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirobi[silafluorene], and a monovalent group of benzoselenophene.

[0033] The heteroaryl as the second substituent also includes a structure in which the heteroaryl is substituted with at least one group selected from the group consisting of aryl such as phenyl (specific examples are the groups described above), alkyl such as methyl (specific examples are the groups described below), and cycloalkyl such as cyclohexyl or adamantyl (specific examples are the groups described below). An example of such a group is a carbazolyl group as the second substituent, where the 9-position is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl. Also included in the heteroaryl group as the second substituent are groups in which a nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl, or carbazolyl is further substituted with phenyl or biphenylyl.

[0034] The "heteroarylene" is, for example, a heteroarylene having 2 to 30 carbon atoms, and preferably a heteroarylene having 2 to 25 carbon atoms, a heteroarylene having 2 to 20 carbon atoms, a heteroarylene having 2 to 15 carbon atoms, or a heteroarylene having 2 to 10 carbon atoms. Furthermore, the "heteroarylene" is, for example, a divalent group such as a heterocycle containing, in addition to carbon, 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms. Specific examples of "heteroarylene" include divalent groups obtained by removing one hydrogen atom from the above-mentioned "heteroaryl" (monovalent group).

[0035] "Diarylamino" is an amino substituted with two aryls, and the details of the aryls can be found in the above explanation of "aryl". "Diheteroarylamino" refers to an amino group substituted with two heteroaryls, and the details of this heteroaryl can be found in the above description of "heteroaryl". "Arylheteroarylamino" refers to an amino group substituted with an aryl and a heteroaryl, and the details of the aryl and heteroaryl can be found in the explanations of "aryl" and "heteroaryl" given above.

[0036] The two aryls in the diarylamino as the first substituent may be bonded to each other via a linking group, the two heteroaryls in the diheteroarylamino as the first substituent may be bonded to each other via a linking group, and the aryl and heteroaryl in the arylheteroarylamino as the first substituent may be bonded to each other via a linking group. Here, the expression "bonded via a linking group" means that, for example, the two phenyls in diphenylamino form a bond via a linking group, as shown below. This explanation also applies to diheteroarylamino and arylheteroarylamino formed by aryls or heteroaryls.

[0037] [ka]

[0038] Specific examples of the linking group include >O and >NR X ,>C(-R X )2, -C(-R X )=C(-R X )-, >Si(-R X )2, >S, >CO, >CS, >SO, >SO2, >SeO, >SeO2, >PO, >B(-R X ), and >Se. R X are each independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl, or heteroaryl. X )2, -C(-R X )=C(-R X )-, >Si(-R X )2,>B(-R X ) two R X is a single bond or a linking group X Y They may be bonded to each other via X to form a ring. Y As >O, >NR Y ,>C(-R Y )2, >Si(-R Y)2, >S, >CO, >CS, >SO, >SO2, and >Se, and R Y are each independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl, or heteroaryl, provided that X Y >C(-R Y )2 and >Si(-R Y )2, two R Y do not bond to form a ring. Further examples of the linking group include alkenylene. Any hydrogen atom in the alkenylene can be independently selected from R 2X and R 2X are each independently alkyl, cycloalkyl, substituted silyl, aryl, or heteroaryl, which may be substituted with alkyl, cycloalkyl, substituted silyl, or aryl. X )=C(-R X )- Two R's X may be bonded to each other to form an aryl ring (such as a benzene ring) or a heteroaryl ring together with the C=C to which they are attached. That is, -C(-R X )=C(-R X )- may be arylene (such as 1,2-phenylene) or heteroarylene.

[0039] In this specification, unless otherwise specified, when "diarylamino," "diheteroarylamino," or "arylheteroarylamino" is simply described, it is assumed that the following explanation is added: "two aryls of the diarylamino may be bonded to each other via a linking group," "two heteroaryls of the diheteroarylamino may be bonded to each other via a linking group," and "aryl and heteroaryls of the arylheteroarylamino may be bonded to each other via a linking group," respectively.

[0040] "Diarylboryl" is a boryl substituted with two aryls, and the details of the aryls can be found in the above description of "aryl." The two aryls may be bonded via a single bond or a linking group (e.g., -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >CO, >C=S, >S=O, >S(=O)2, >Se(=O), >Se(=O)2, >P(=O), >B(-R), >C(-R)2, >Si(-R)2, or >Se). Here, R in -CR=CR-, R in >NR, R in >B(-R), R in >C(-R), and R in >Si(-R) are aryl, heteroaryl, diarylamino, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen atom in the R may be further substituted with an aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. Two adjacent Rs may be bonded to form a ring, forming a cycloalkylene, arylene, or heteroarylene. For details of the substituents listed here, the above-mentioned descriptions of "aryl," "arylene," "heteroaryl," "heteroarylene," and "diarylamino," as well as the below-mentioned descriptions of "alkyl," "alkenyl," "alkynyl," "cycloalkyl," "cycloalkylene," "alkoxy," and "aryloxy" may be cited. Furthermore, when the term "diarylboryl" is used simply in this specification, unless otherwise specified, it is understood to include the explanation that "the two aryls of the diarylboryl may be bonded to each other via a single bond or a linking group."

[0041] The "alkyl" may be either straight-chain or branched-chain, for example, a straight-chain alkyl having 1 to 24 carbon atoms or a branched-chain alkyl having 3 to 24 carbon atoms, and is preferably an alkyl having 1 to 18 carbon atoms (branched-chain alkyl having 3 to 18 carbon atoms), an alkyl having 1 to 12 carbon atoms (branched-chain alkyl having 3 to 12 carbon atoms), an alkyl having 1 to 6 carbon atoms (branched-chain alkyl having 3 to 6 carbon atoms), an alkyl having 1 to 5 carbon atoms (branched-chain alkyl having 3 to 5 carbon atoms), or an alkyl having 1 to 4 carbon atoms (branched-chain alkyl having 3 to 4 carbon atoms).

[0042] Specific examples of "alkyl" include methyl, ethyl, n-propyl, isopropyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1,1,2,2-tetramethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-ethylbutyl, 1,1-dimethylbutyl, 3,3-dimethylbutyl, 1,1-diethylbutyl, 1-ethyl-1-methylbutyl, 1-propyl-1-methylbutyl, 1,1,3-trimethylbutyl, 1-ethyl-1,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, t-pentyl (t-amyl), 1-methylpentyl, 2-propylpentyl, 1,1-dimethylpentyl, 1-ethyl-1-methylpentyl, 1-propyl-1 -methylpentyl, 1-butyl-1-methylpentyl, 1,1,4-trimethylpentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 1,1-dimethylhexyl, 1-ethyl-1-methylhexyl, 1,1,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-heptyl, 1-methylheptyl, 1-hexylheptyl, 1,1-dimethylheptyl, 2,2-dimethylhexyl Examples of the alkyl group include methylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, t-octyl (1,1,3,3-tetramethylbutyl), 1,1-dimethyloctyl, n-nonyl, n-decyl, 1-methyldecyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-eicosyl.

[0043] An "alkylene" is a divalent group obtained by removing any hydrogen from an "alkyl", such as methylene, ethylene, or propylene.

[0044] For "alkenyl," the explanation of "alkyl" above can be referred to. It is a group in which a C═C single bond in the "alkyl" structure is replaced with a C═C double bond, and also includes groups in which not only one but two or more single bonds are replaced with double bonds (also called alkadiene-yl or alkatriene-yl).

[0045] "Alkenylene" is a divalent group obtained by removing any hydrogen from "alkenyl", and examples include vinylene.

[0046] For "alkynyl," the explanation of "alkyl" above can be referred to. It is a group in which a C≡C single bond in the "alkyl" structure is replaced with a C≡C triple bond, and also includes groups in which not only one but two or more single bonds are replaced with triple bonds (also called alkadiyn-yl or alkatolyyn-yl).

[0047] The "cycloalkyl" is, for example, a cycloalkyl having 3 to 24 carbon atoms, and preferably a cycloalkyl having 3 to 20 carbon atoms, a cycloalkyl having 3 to 16 carbon atoms, a cycloalkyl having 3 to 14 carbon atoms, a cycloalkyl having 3 to 12 carbon atoms, a cycloalkyl having 5 to 10 carbon atoms, a cycloalkyl having 5 to 8 carbon atoms, a cycloalkyl having 5 to 6 carbon atoms, or a cycloalkyl having 5 carbon atoms.

[0048] Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyl (particularly methyl) substituted derivatives thereof having 1 to 5 carbon atoms or 1 to 4 carbon atoms, bicyclo[1.1.0]butyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl (norbornyl), bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphthalenyl, and decahydroazulenyl.

[0049] "Cycloalkylene" is, for example, cycloalkylene having 3 to 24 carbon atoms, and preferably cycloalkylene having 3 to 20 carbon atoms, cycloalkylene having 3 to 16 carbon atoms, cycloalkylene having 3 to 14 carbon atoms, cycloalkylene having 3 to 12 carbon atoms, cycloalkylene having 5 to 10 carbon atoms, cycloalkylene having 5 to 8 carbon atoms, cycloalkylene having 5 to 6 carbon atoms, cycloalkylene having 5 carbon atoms, etc. A specific example of "cycloalkylene" is a structure in which one hydrogen atom is removed from the above-mentioned "cycloalkyl" (monovalent group) to form a divalent group.

[0050] "Cycloalkenyl" refers to a group having a structure in which at least one pair of single bonds between two carbon atoms in the above-mentioned "cycloalkyl" has become a double bond (for example, a group in which -CH-CH- is replaced with -CH=CH-), and does not fall under the category of aryl. Specific examples include 1-cyclohexenyl and 1-cyclopentenyl.

[0051] "Alkoxy" is a group represented by "Alk-O- (Alk is alkyl)", and the above explanation of "alkyl" can be cited for details of the alkyl.

[0052] "Aryloxy" is a group represented by "Ar-O-(Ar is aryl)", and the above explanation of "aryl" can be cited for details of the aryl.

[0053] The "substituted silyl" is, for example, a silyl substituted with at least one of aryl, alkyl, and cycloalkyl, and is preferably triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, or alkyldicycloalkylsilyl.

[0054] "Triarylsilyl" is a silyl group substituted with three aryl groups, and the details of the aryl groups can be found in the above description of "aryl." Specific examples of "triarylsilyl" include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl.

[0055] "Trialkylsilyl" is a silyl group substituted with three alkyl groups, and the details of this alkyl can be found in the above explanation of "alkyl". Specific examples of the "trialkylsilyl" include trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-s-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldiethylsilyl, isopropyldiethylsilyl, n-butyldiethylsilyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, s-butyldi-n-propylsilyl, t-butyldi-n-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, and t-butyldiisopropylsilyl.

[0056] "Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyl groups, and the details of this cycloalkyl can be found in the above description of "cycloalkyl". Specific "tricycloalkylsilyl" includes, for example, tricyclopentylsilyl or tricyclohexylsilyl.

[0057] "Dialkylcycloalkylsilyl" is a silyl group substituted with two alkyls and one cycloalkyl, and the details of the alkyl and cycloalkyl can be found in the explanations of "alkyl" and "cycloalkyl" above.

[0058] "Alkyldicycloalkylsilyl" is a silyl group substituted with one alkyl and two cycloalkyl, and the details of the alkyl and cycloalkyl can be found in the explanations of "alkyl" and "cycloalkyl" above.

[0059] "Halogen" is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, and even more preferably fluorine.

[0060] When cyano or halogen is substituted, it is also preferred that all or part of the hydrogen atoms in the aryl or heteroaryl in the structure are replaced with cyano or halogen.

[0061] The substituent represented by formula (A30) has the following structure: [ka]

[0062] In formula (A30), Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted cycloalkenyl, in which at least one -CH2- may be replaced by -O- or -S-; R Ak is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl, or a substituted or unsubstituted cycloalkyl; R Ak may be bonded to Ak via a linking group or a single bond, and * indicates the bonding position.

[0063] In formula (A30), Ak is the above-mentioned substituent, so it does not conjugate with the lone electron pair on N, and therefore the lone electron pair can be conjugated with the π electron to which it is bonded, allowing for a greater wavelength shift than when there is an aryl or the like at the same position. This also has a similar effect on the multiple resonance effect, allowing for a greater improvement in thermally activated delayed fluorescence (TADF) properties.

[0064] R Ak is preferably aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, alkyl or cycloalkyl, more preferably aryl which may be substituted with alkyl, heteroaryl which may be substituted with alkyl, alkyl or cycloalkyl, still more preferably aryl which may be substituted with alkyl, and particularly preferably phenyl which may be substituted with methyl.

[0065] In formula (A30), Ak is preferably alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 14 carbon atoms, more preferably alkyl having 1 to 4 carbon atoms or cycloalkyl having 3 to 8 carbon atoms, more preferably alkyl having 1 to 4 carbon atoms, and even more preferably methyl.

[0066] R Ak and Ak may be the same or different, and are preferably different.

[0067] R Ak may be bonded to Ak via a linking group or a single bond. In this case, examples of the linking group include >O, >S, and >Si(-R)2. R in >Si(-R)2 is hydrogen, an aryl having 6 to 12 carbon atoms, an alkyl having 1 to 6 carbon atoms, or a cycloalkyl having 3 to 14 carbon atoms. R Ak Examples of the structure in which is bonded to Ak via a linking group or a single bond include the following:

[0068] [ka] In the above formulas, * indicates the bonding position.

[0069] <When two groups bonded to the same atom are bonded to each other> In the present specification, when it is stated that two groups bonded to the same atom may be bonded to each other to form a ring, they may be bonded by a single bond or a linking group (collectively also referred to as a linking group), and examples of the linking group include -CH2-CH2-, -CHR-CHR-, -CR2-CR2-, -CH=CH-, -CR=CR-, -C≡C-, -N(-R)-, -O-, -S-, -C(-R)2-, -C(=O)-, -C(=S)-, -S(=O)-, -S(=O)2-, -Se(=O)-, -Se(=O)2-, -P(=O)-, -B(-R)-, -Si(-R)2-, and -Se-, for example, the following structure. R of -CHR-CHR-, R of -CR-CR-, R of -CR=CR-, R of -N(-R)-, R of -C(-R)-, R of -B(-R)-, and R of -Si(-R)- are each independently hydrogen, aryl optionally substituted with alkyl or cycloalkyl, heteroaryl optionally substituted with alkyl or cycloalkyl, alkyl optionally substituted with cycloalkyl, alkenyl optionally substituted with alkyl or cycloalkyl, alkynyl optionally substituted with alkyl or cycloalkyl, or cycloalkyl optionally substituted with alkyl or cycloalkyl. Two adjacent Rs may be bonded to form a ring, forming a cycloalkylene, arylene, or heteroarylene.

[0070] [ka]

[0071] As the linking group, a single bond and -CR=CR-, -N(-R)-, -O-, -S-, -C(-R)2-, -Si(-R)2-, and -Se- are preferred, a single bond and -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R)2- as linking groups are more preferred, a single bond and -CR=CR-, -N(-R)-, -O-, and -S- as linking groups are even more preferred, and a single bond is most preferred.

[0072] The position at which two Rs are bonded by the bonding group is not particularly limited as long as it is a position where bonding is possible, but it is preferable that they are bonded at the most adjacent positions. For example, when the two groups are phenyl, it is preferable that they are bonded at positions ortho (2nd position) relative to the bonding position (1st position) of "C" or "Si" in the phenyl (see the structural formula above).

[0073] <Stereoisomers, etc.> The polycyclic aromatic compounds of the present invention may exist as enantiomers or diastereomers depending on the type of substituents, etc., but regardless of the structural formula shown, any pure stereoisomer, any mixture of stereoisomers, racemate, etc. are all intended to be encompassed within the scope of the present invention.

[0074] 1. Polycyclic aromatic compounds <Explanation of the overall structure of the compound> It has already been found that polycyclic aromatic compounds in which aromatic rings are linked by heteroatoms such as boron, nitrogen, oxygen, and sulfur have large HOMO-LUMO gaps (band gaps in thin films, Eg). This is because the six-membered rings containing heteroatoms have low aromaticity, suppressing the decrease in the HOMO-LUMO gap associated with the expansion of the conjugated system. We have also found that the HOMO-LUMO gap can be arbitrarily changed depending on the type and linking method of the heteroatoms. This is thought to be due to the ability to arbitrarily change the HOMO and LUMO energies depending on the spatial extent and energy of the unoccupied orbitals or lone pairs of the heteroatoms.

[0075] These polycyclic aromatic compounds have narrow half-widths of their fluorescence emission peaks due to the localization of the excited SOMO1 and SOMO2 atoms on each atom caused by electronic perturbation of the heteroatoms, resulting in emission of high color purity when used as dopants in organic electroluminescent devices. For the same reason, ΔE(S1T1) is small, resulting in thermally activated delayed fluorescence, and high efficiency can be achieved when used as an emitting dopant in organic electroluminescent devices. Furthermore, by introducing substituents, the HOMO and LUMO energies can be adjusted arbitrarily, making it possible to optimize the ionization potential and electron affinity depending on the surrounding materials.

[0076] The polycyclic aromatic compound of the present invention corresponds to a polycyclic aromatic compound in which the aromatic rings are linked by hetero elements such as boron, nitrogen, oxygen, and sulfur, and has a structure represented by formula (1). [ka] The symbols in formula (1) will be described in detail later.

[0077] In the present invention, it has been found that an organic EL device using a polycyclic aromatic compound represented by formula (1) has high efficiency and a long life, and also has a large CIEy value and high green color purity.

[0078] <Explanation of ring structure in compounds> In formula (1), ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring. In formula (1), the letters "A," "B," "C," "E," "G," "I," "J," and "K" in the circles indicate the ring structure represented by each circle. The structure represented by formula (1) has at least 11 aromatic rings, namely, ring A, ring B, ring C, ring d, ring E, ring f, ring G, ring h, ring I, ring J, and ring K, connected by boron and heteroatoms such as oxygen, sulfur, or nitrogen to form further ring structures. The formed ring structure is a fused ring structure consisting of at least 21 rings.

[0079] In formula (1), ring A and ring B may be bonded to each other via a single bond or a linking group, ring B and ring C may be bonded to each other via a single bond or a linking group, ring E and ring G may be bonded to each other via a single bond or a linking group, ring I and ring J may be bonded to each other via a single bond or a linking group, and ring J and ring K may be bonded to each other via a single bond or a linking group. Here, when it is said that rings are bonded to each other via a single bond or a linking group, it means that they are bonded via an additional bond not described in formula (1), as schematically shown by the dotted line in formula (1') below. That is, the polycyclic aromatic compound represented by formula (1) may have a bond via an additional single bond or a linking group in at least one selected from the group consisting of between ring A and ring B, between ring B and ring C, between ring E and ring G, between ring I and ring J, and between ring J and ring K. [ka]

[0080] In formula (1), ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K each form a divalent group having bonds to two adjacent atoms (preferably carbon) on the aryl or heteroaryl ring in the structure. Ring A, ring B, ring E, ring G, ring J, and ring K are each bonded to N (nitrogen) and B (boron) via the two bonds, and ring C is bonded to X via the two bonds. 1 and B (boron), and the I ring is connected to X by the above two bonds. 2 and B (boron). When each ring is further bonded to another ring via a single bond or a linking group as described above, it may form a trivalent or tetravalent group. X 1 may be further bonded to ring C at another position to form a trivalent or tetravalent group as described below, and X 2 may be further bonded to ring I at another position as described below, so that ring I forms a trivalent or tetravalent group.

[0081] In each of rings A, B, C, E, G, I, J, and K, the ring having the atoms having the two bonds as ring constituent atoms is preferably a 5- or 6-membered ring, more preferably a 6-membered ring. This ring may be further fused with another ring. Examples of 6-membered rings include a benzene ring, a pyridine ring, a pyrazine ring, and a pyrimidine ring. Examples of 6-membered rings further fused with another ring include a naphthalene ring, a quinoline ring, a benzofuran ring, a benzothiophene ring, an indole ring, a benzoselenophene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, and a dibenzoselenophene ring. Examples of 5-membered rings include a furan ring, a thiophene ring, a pyrrole ring, a thiazole ring, and a selenophene ring. Examples of 5-membered rings further fused with another ring include a benzofuran ring, a benzothiophene ring, an indole ring, an indene ring, and a benzoselenophene ring. The aryl ring or heteroaryl ring in ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K is preferably a benzene ring, a benzofuran ring, a benzothiophene ring, or a benzoselenophene ring, more preferably a benzene ring, a benzofuran ring, or a benzothiophene ring, and even more preferably a benzene ring or a benzothiophene ring.

[0082] Specifically, in formula (1), ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each preferably independently a substituted or unsubstituted aryl ring or a structure represented by formula (1A-L). Here, the aryl ring is preferably a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, or a substituted or unsubstituted pyrene ring, and more preferably a substituted or unsubstituted benzene ring (substituted or unsubstituted 1,2-phenylene). [ka]

[0083] In formula (1A-L), one of the two * represents nitrogen, and X 1 , or X 2The other is the bonding position to B (boron). In formula (1A-L), Z is =C(-R Z )- or =N-, and R Z is hydrogen or a substituent.

[0084] In formula (1A-L), each L is independently >O, >S, >Se, or >NR NL , >Si(-R IL )2, or >C(-R CL )2 and R NL , R IL , and R CL are each independently hydrogen, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl, or optionally substituted cycloalkyl; CL may be bonded to each other to form a ring, and two R IL may be bonded to each other to form a ring. NL R when NL is preferably a substituted or unsubstituted aryl, and more preferably a phenyl which may be substituted with alkyl. CL )2 when R CL is preferably methyl or phenyl. L is preferably >O or >S, more preferably >S.

[0085] It is preferred that rings A, B, C, E, G, I, J, and K are each independently a substituted or unsubstituted benzene ring, a substituted or unsubstituted benzofuran ring, or a substituted or unsubstituted benzothiophene ring. Here, the benzofuran ring and the benzothiophene ring are bonded to boron at a ring-constituting atom of a five-membered ring. It is more preferred that rings A, B, C, E, G, I, J, and K are each independently a substituted or unsubstituted benzene ring.

[0086] In the substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings in the rings A, B, C, E, G, I, J, and K of the compound represented by formula (1), the substituents (R Z The substituent Zα includes at least one substituent selected from the substituent group Zα. The substituent may be a substituted or unsubstituted diarylphosphino such as diphenylphosphino, or a substituted or unsubstituted diarylphosphinyl such as diphenylphosphinyl. When a plurality of substituents are present, the plurality of substituents may be the same or different. The substituent is preferably a substituted or unsubstituted alkyl, a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted diarylamino, a cyano, or a halogen, and more preferably t-butyl, diphenylamino, a substituted or unsubstituted carbazolyl, a cyano, or a halogen. Other preferred substituents include a group represented by formula (1L) described below. The description in the section <Preferred Substituents> described below can also be referred to.

[0087] In the formula (1), Z in the d-ring, f-ring, and h-ring is =C(-R Z )- or =N-, and R Z is hydrogen or a substituent. R in rings d, f, and h Z The substituent as R may be at least one substituent selected from the substituent group Zα, and is preferably unsubstituted alkyl or cyano, more preferably methyl. Z is preferably hydrogen, i.e., Z is preferably =C(-H)-.

[0088] <X 1 and X 2 Description> X 1 and X 2 are independently >NR NX ,>O,>C(-R CX )2, >Si(-R IX)2, >S, or >Se. R NX is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; R CX and R IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; CX may be bonded to each other to form a ring, and two R IX may be bonded to each other to form a ring. 1 R in NX , R CX and R IX may be bonded to at least one of the C ring and the d ring (Z) via a linking group or a single bond, and X 2 R in NX , R CX and R IX may be bonded to at least one of the ring h (Z) and the ring I via a linking group or a single bond.

[0089] R NX R is preferably a substituted or unsubstituted aryl or a substituted or unsubstituted heteroaryl, more preferably a group represented by the formula (1L) described below or a substituted or unsubstituted phenyl, and even more preferably a group represented by the formula (1L), a phenyl substituted with cyano, or an unsubstituted phenyl. CX R is preferably a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, or a substituted or unsubstituted alkyl, and more preferably a substituted or unsubstituted phenyl or methyl. IX is preferably a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, or a substituted or unsubstituted alkyl, and more preferably a substituted or unsubstituted phenyl or methyl.

[0090] In the polycyclic aromatic compound represented by formula (1) used as an emitting dopant in the light-emitting layer of an organic EL device, X 1 and X2 are independently >NR NX , >S, >O, or >Se, and >NR NX , >O, or >S, and more preferably >NR NX or more preferably >S, and more preferably >NR NX It is particularly preferred that:

[0091] <X 1 and X 2 Explanation of the change in ring structure due to bonding with the ring> X 1 R in NX , R CX and R IX may be bonded to at least one of the C ring and the d ring (Z) via a linking group or a single bond, and X 2 R in NX , R CX and R IX may be bonded to at least one of the ring h (Z) and the ring I via a linking group or a single bond. As mentioned above, R NX is bonded to the ring via a single bond or a linking group, which is expected to stabilize the substituent or the molecule itself through bond formation, modify the HOMO and LUMO orbitals, adjust the extent of conjugation, adjust donor or acceptor properties, and provide a heavy atom effect, as well as adjust the lowest excited singlet energy, lowest excited triplet energy, higher excited singlet energy, or higher excited triplet energy. These effects, acting singly or in combination, can result in improved thermal, chemical, or electrical stability, shorter or longer emission wavelength, narrower emission spectrum or lower second peak, increased emission quantum yield, improved TADF properties, and even higher efficiency and longer life when used as a material for constituting devices.

[0092] R NX , R CX and R IXExamples of the linking group when each is bonded to a ring include -CH2-CH2-, -CHR-CHR-, -CR2-CR2-, -CH=CH-, -CR=CR-, -C≡C-, -N(-R)-, -O-, -S-, -C(-R)2-, -C(=O)-, -C(=S)-, -S(=O)-, -S(=O)2-, -Se(=O)-, -Se(=O)2-, -P(=O)-, -B(-R)-, -Si(-R)2-, and -Se-. Of these, -CH=CH-, -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R)2- are preferred, -CH=CH-, -CR=CR-, -N(-R)-, -O-, and -S- are more preferred, and -CR=CR-, -N(-R)-, -O-, and -S- are even more preferred. The R of "-CHR-CHR-", R of "-CR-CR-", R of "-CR=CR-", R of "-N(-R)-", R of "-C(-R)-", R of "-B(-R)-", and R of "-Si(-R)-" are each independently hydrogen, aryl optionally substituted with alkyl or cycloalkyl, heteroaryl optionally substituted with alkyl or cycloalkyl, alkyl optionally substituted with alkyl or cycloalkyl, alkenyl optionally substituted with alkyl or cycloalkyl, alkynyl optionally substituted with alkyl or cycloalkyl, or cycloalkyl optionally substituted with alkyl or cycloalkyl. Two Rs bonded to the same atom may be bonded to each other to form a ring. Two adjacent Rs may be bonded to each other to form a cycloalkylene ring, an arylene ring, or a heteroarylene ring. These rings may also be substituted with alkyl or cycloalkyl.

[0093] >NR NX R in NX Examples of the fused ring formed by bonding with the benzene ring or the d or h ring as the aryl ring in the C or I ring include a carbazole ring (R NX is bonded by a single bond), phenoxazine ring (R is phenyl NX -O- bond), phenothiazine ring (phenyl R NX-S- bonded), or an acridone ring (R is phenyl NX The bond is -C(=O)-. NX Examples of the fused ring formed by bonding with a benzene ring as an aryl ring in ring A, ring B, ring C, ring G, ring H, or ring I are shown below.

[0094] [ka]

[0095] In the above formula, (*B) is the bonding position to boron, and the benzene ring to which (*B) is directly bonded is the benzene ring in ring C or ring I, or the d-ring or h-ring. * is the bonding position to the aryl ring or heteroaryl ring in ring C or ring I, or the bonding position to the d-ring or h-ring. Except when a carbazole ring is formed, * is the bonding position to the d-ring or h-ring (R NX is bonded to ring C or ring I). Any of the above fused rings may have a substituent not shown in the above formula at a carbon atom constituting one of the rings.

[0096] Also, R NX and a ring in ring C or ring I, or ring d or ring h (preferably a ring in ring C or ring I) may be linked to form the following partial structure (A10): [ka]

[0097] In formula (A10), R A1 ~R A4 are each independently hydrogen, optionally substituted alkyl, or optionally substituted cycloalkyl; R A1 ~R A4 Any two to four of these may be bonded to each other via a linking group or a single bond, and X 1 or X 2is bonded to one of the two rings at the position **, and to the other ring at the position **. That is, N in formula (A10) is X 1 or X 2 >NR X >NR when X The atoms on the ring bonded at the two * positions may be adjacent atoms (preferably carbon atoms). The partial structure represented by formula (A10) contains an N-C bond with a weak bond dissociation energy (BDE), but the presence of another bond forming a ring promotes a reverse reaction (recombination reaction) even when the N-C bond is broken, resulting in a more stable structure. Therefore, organic EL devices manufactured using polycyclic aromatic compounds having such structures are expected to have a longer device life. When a polycyclic aromatic compound contains a structure represented by formula (A10), the number of such structures may be one or two (preferably one).

[0098] In formula (A10), R A1 ~R A4 Any two to four of these may be linked to each other via a linking group or a single bond. R A1 ~R A4 is any two (R A1 and R A4 , R A1 and R A4 and R A2 and R A3 , R A1 and R A2 , R A3 and R A4 , R A1 and R A2 and R A3 and R A4 ) are preferably bonded to each other by a linking group or a single bond, and R A1 and R A4are more preferably bonded to each other via a linking group or a single bond. An example of the divalent group formed by bonding to each other is alkylene. At least one hydrogen in the alkylene may be substituted with an alkyl or cycloalkyl, and at least one (preferably one) -CH2- in the alkylene may be substituted with -O- and -S-. The divalent group formed by bonding to each other is preferably a straight-chain alkylene having 2 to 5 carbon atoms, more preferably a straight-chain alkylene having 3 or 4 carbon atoms, and even more preferably a straight-chain alkylene having 4 carbon atoms (-(CH2)4-). It is particularly preferred that the straight-chain alkylene having 4 carbon atoms (-(CH2)4-) is unsubstituted.

[0099] The remaining R that is not involved in the linkage by the linking group A1 ~R A4 are each independently preferably hydrogen or an alkyl which may be substituted, more preferably an alkyl having 1 to 6 carbon atoms which may be substituted, further preferably an unsubstituted alkyl having 1 to 6 carbon atoms, and most preferably methyl. That is, the partial structure represented by formula (A10) is preferably a structure represented by the following formula (A11).

[0100] [ka] In formula (A11), Me is methyl, and is bonded to one of the two rings to which X is bonded at the positions marked with two *, and to the other ring at the position marked with **.

[0101] <Ring connection> In one embodiment of the present invention, the polycyclic aromatic compound represented by formula (1) preferably satisfies at least one of (B-1) to (B-7). (B-1)X 1 >NR NX and X 1 R in NX is attached to ring C or ring d via a single bond or a linking group; (B-2)X 2>NR NX and X 2 R in NX is attached to ring I or ring h via a single bond or a linking group; (B-3) Ring A and ring B are bonded to each other via a single bond or a linking group; (B-4) Ring B and ring C are bonded to each other via a single bond or a linking group; (B-5) Ring E and ring G are bonded to each other via a single bond or a linking group; (B-6) Ring I and ring J are bonded to each other via a single bond or a linking group; (B-7) The J ring and the K ring are bonded to each other via a single bond or a linking group. In particular, one of the following is preferred: X 1 , X 2 are >NR NX and X 1 R in NX is bonded to ring C via a single bond or a linking group, and X 2 R in NX is attached to ring I via a single bond or a linking group; X 1 , X 2 are >NR NX and X 1 R in NX is bonded to the d ring via a single bond or a linking group, and X 2 R in NX is attached to the h ring via a single bond or a linking group; · (B-3) and (B-7) are satisfied simultaneously; · (B-4) and (B-6) are satisfied simultaneously.

[0102] <Formula (1-a)~Formula (1-w)> Examples of the polycyclic aromatic compound represented by formula (1) include polycyclic aromatic compounds represented by the following formulas (1-a) to (1-w).

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] Formulas (1-a) to (1-w) correspond to the rings A, B, C, E, G, I, J, and K in formula (1) in which a specific 6-membered ring or a fused ring of a 5-membered ring and a 6-membered ring is selected. In this sense, A, B, C, E, G, I, J, and K in formula (1) are represented by lowercase letters a, b, c, e, g, i, j, and k in formula (1-a) to formula (1-w), respectively. In addition, the fused rings corresponding to A, B, C, E, G, I, J, and K are represented by lowercase letters a, b, c, e, g, i, j, and k, respectively. 1 , b 1 , c 1 (or c 2 ), e 1 (or e 2 ), g 1 (or g 2 ), i 1 (or i 2 ), j 1 , and k 1 It is expressed as:

[0107] (1-a)~In formula (1-w), X 1 and X 2 is X in equation (1). 1 and X 2 and the preferred ranges are also the same.

[0108] (1-a)~In formula (1-w), L 1 ~L 14 are independently >O, >S, >Se, and >NR NL , >Si(-R IL )2, or >C(-R CL )2 and R NL , R IL, and R CL are each independently hydrogen, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl, or optionally substituted cycloalkyl; CL may be bonded to each other to form a ring, and two R IL may be bonded to each other to form a ring.

[0109] In formulas (1-a) to (1-w), Z has the same meaning as Z in formula (1), and =C(-R Z )- or =N-, and R Z is hydrogen or a substituent. Z is at least one substituent selected from the substituent group Zα, preferably substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino, cyano, or halogen, more preferably t-butyl, substituted or unsubstituted diphenylamino, or substituted or unsubstituted N-carbazolyl, and even more preferably substituted or unsubstituted N-carbazolyl. The substituent in the substituted or unsubstituted N-carbazolyl is at least one substituent selected from the group consisting of substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, and substituted or unsubstituted cycloalkyl. Other preferred substituents include the group represented by formula (1L) described below. The description in the <Preferred Substituents> section below can also be referenced.

[0110] In each of the formulas (1-a) to (1-w), the substituent R Z The preferred positions of are the para positions of the nitrogen atoms in the b and j rings.

[0111] In each of the formulas (1-a) to (1-w), X 1 R in NX , R CX and R IX is a c-ring, c 1 Ring, or c 2may be bonded to at least one of the ring (Z) and the d ring (Z) via a linking group or a single bond, and X 2 R in NX , R CX and R IX is the h-ring (Z) and In each of the formulas (1-a) to (1-w), X 1 R in NX , R CX and R IX is the i-ring, i 1 Ring, or i 2 It may be bonded to at least one of the rings (Z) via a linking group or a single bond.

[0112] In each of the formulas (1-a) to (1-w), L 1 ~L 14 are >NR NL R when NL L is preferably a substituted or unsubstituted aryl, and more preferably a phenyl which may be substituted with alkyl. 1 ~L 14 >C(-R CL )2 when R CL As L, methyl or phenyl is preferred. 1 ~L 14 is preferably >O or >S, more preferably >S.

[0113] <Group represented by formula (1L)> The polycyclic aromatic compound represented by formula (1) preferably contains at least one group represented by the following formula (1L) as a partial structure. [ka]

[0114] In formula (1L), ring L is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, and R Lis a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted arylthio, a substituted or unsubstituted heteroarylthio, a substituted or unsubstituted aryloxy, a substituted or unsubstituted heteroaryloxy, a substituted alkyl, an unsubstituted alkyl having 3 to 24 carbon atoms, or a substituted or unsubstituted cycloalkyl. * indicates the bonding position to another moiety of the polycyclic aromatic compound represented by formula (1). The partial structure represented by formula (1L) may be contained, for example, as any of the following: a substituent of an aryl or heteroaryl ring in at least one selected from the group consisting of ring A, ring B, ring C, ring d, ring E, ring f, ring G, ring h, ring I, ring J, and ring K, preferably a substituent of an aryl or heteroaryl ring in at least one selected from the group consisting of ring A, ring B, ring C, ring E, ring f, ring G, ring h, ring I, ring J, and ring K; X 1 and X 2 R in at least one selected from the group consisting of NX , R CX , or R IX a partial structure in the formula: NX R in NX

[0115] The polycyclic aromatic compound of the present invention has a group represented by formula (1L), and therefore, R NX By having a group represented by formula (1L) as the cation, the green color purity is increased compared to similar compounds that do not have this group. Without being bound by any particular theory, it is believed that the emission spectrum with high color purity is achieved by introducing a group represented by formula (1J) into a highly planar molecular structure, which reduces the proportion of structures that exist on the same plane in the entire molecule, thereby reducing intermolecular stacking.

[0116] In formula (1L), R L In terms of ease of synthesis, R L is preferably unsubstituted phenyl.

[0117] In formula (1L), "L" in a circle is a symbol indicating the ring structure shown by the circle, and ring L is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring. Ring L forms a divalent group having bonds to two adjacent elements (preferably carbon) on the aryl ring or heteroaryl ring in the structure, and the two bonds connect other parts of the polycyclic aromatic compound represented by formula (1) (such as the position of N (nitrogen)) and R L That is, R L is in the ortho position of the bond position (*).

[0118] In the substituted or unsubstituted aryl ring or substituted or unsubstituted heteroaryl ring in ring L, the substituent when referred to as "substituted or unsubstituted (substituted or unsubstituted)" is preferably at least one substituent selected from the substituent group Zα.

[0119] The L ring is preferably a substituted or unsubstituted benzene ring, a substituted or unsubstituted benzothiophene ring, a substituted or unsubstituted benzofuran ring, or a substituted or unsubstituted indole ring, more preferably a substituted or unsubstituted benzene ring, and even more preferably an unsubstituted benzene ring.

[0120] A preferred example of the group represented by formula (1L) is a group represented by formula (1L-a). [ka]

[0121] In formula (1L-a), Z L are each independently -C(-R L )= or -N= and R L and R m are each independently hydrogen or a substituent selected from the substituent group Zα, and R L adjacent groups bond together to form the L' ring, and R mAdjacent groups among these may be bonded to each other to form an aryl ring or a heteroaryl ring together with the ring m, and the formed ring may be substituted with at least one substituent selected from the substituent group Zα. L Adjacent groups of are bonded together to form the L ring, or R m Examples of the ring formed by bonding adjacent groups together with the k ring include a naphthalene ring, a carbazole ring, an indole ring, a dibenzofuran ring, and a dibenzothiophene ring.

[0122] R m are each preferably independently hydrogen, unsubstituted alkyl, unsubstituted cycloalkyl, or cyano, and more preferably hydrogen or unsubstituted alkyl. R m must all be hydrogen or at least two R m is unsubstituted alkyl or unsubstituted cycloalkyl, and other R m is preferably hydrogen, unsubstituted alkyl, or unsubstituted cycloalkyl. Z L are both -C(-R L )=. R L are each preferably independently hydrogen, unsubstituted alkyl, unsubstituted cycloalkyl, or cyano, and more preferably hydrogen or unsubstituted alkyl.

[0123] In formula (1L-a), Z L are both -C(-R L )= and R L and R m is preferably each independently hydrogen or unsubstituted alkyl. In one preferred embodiment of formula (1L-a), R L and R m are preferably all hydrogen, that is, the group represented by formula (1L-a) is 2-biphenylyl. In another preferred embodiment of formula (1L-a), at least two R mis unsubstituted alkyl or unsubstituted cycloalkyl, and other R m is preferably hydrogen.

[0124] Other preferred examples of the group represented by formula (1L) include groups represented by formula (1L-b). [ka]

[0125] In formula (1L-b), R L2 is R in formula (1L) L The meaning and preferred range are also the same. LL is R L The meaning and preferred range are also the same. L is Z in formula (1L-a) L In the group represented by formula (1L-b), Z L are both -CH=, and R L2 , R LL is preferably an unsubstituted phenyl.

[0126] Still another preferred example of the group represented by formula (1L) is a group represented by formula (1L-c). [ka]

[0127] In formula (1L-c), R L is R in formula (1L) L The meaning and preferred range are also the same. L is Z in formula (1L-a) Land the preferred range is also the same. X is >NR, >O, or >S, and R in >NR is hydrogen, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkyl, or optionally substituted cycloalkyl. R in >NR is preferably optionally substituted aryl or optionally substituted heteroaryl, and more preferably unsubstituted aryl (particularly unsubstituted phenyl).

[0128] In formula (1L-c), Z L are both -C(-R L ) =, and two R L Preferably, two R are bonded to each other to form an aryl or heteroaryl ring together with the L ring. L The ring formed by bonding to each other together with ring L is preferably a substituted or unsubstituted benzofuran ring, a substituted or unsubstituted benzothiophene ring, or a substituted or unsubstituted indole ring, more preferably an unsubstituted benzofuran ring, an unsubstituted benzothiophene ring, or an unsubstituted indole ring.

[0129] When the polycyclic aromatic compound of the present invention contains a group represented by formula (1L), the number of groups is not particularly limited, but is preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 to 2. When a plurality of groups represented by formula (1L) are present, they may be the same or different, but are preferably the same. The polycyclic aromatic compound of the present invention has a group represented by formula (1L) that is substituted by >NR NX R NX In formula (1), X 1 and X 2 All are >NR NX and two R NX are particularly preferably groups represented by formula (1L).

[0130] <Preferred Substituents> In polycyclic aromatic compounds used as emitting dopants (and in other compounds used as dopants), a tertiary alkyl represented by the following formula (tR) is particularly preferred as an "alkyl"-containing substituent. This is because such bulky substituents increase the intermolecular distance, thereby improving the luminescence quantum yield (PLQY). Substituents in which the tertiary alkyl represented by formula (tR) is substituted with another substituent as a second substituent are also preferred. Specific examples include diarylamino substituted with a tertiary alkyl represented by formula (tR), carbazolyl (preferably N-carbazolyl) substituted with a tertiary alkyl represented by formula (tR), or benzocarbazolyl (preferably N-benzocarbazolyl) substituted with a tertiary alkyl represented by formula (tR). Substitution of the group of formula (tR) on diarylamino, carbazolyl and benzocarbazolyl includes examples in which some or all of the hydrogen atoms on the aryl ring or benzene ring in these groups are replaced with a group of formula (tR).

[0131] [ka]

[0132] In the formula (tR), R a , R b , and R c are each independently alkyl having 1 to 24 carbon atoms, any —CH2— in the alkyl may be substituted with —O—, and the group represented by formula (tR) is bound to *.

[0133] R a , R b and R cThe "alkyl having 1 to 24 carbon atoms" may be either a straight chain or a branched chain, and examples thereof include a straight chain alkyl having 1 to 24 carbon atoms or a branched chain alkyl having 3 to 24 carbon atoms, an alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms), an alkyl having 1 to 12 carbon atoms (branched chain alkyl having 3 to 12 carbon atoms), an alkyl having 1 to 6 carbon atoms (branched chain alkyl having 3 to 6 carbon atoms), and an alkyl having 1 to 4 carbon atoms (branched chain alkyl having 3 to 4 carbon atoms).

[0134] R in formula (tR) a , R b , and R c The total number of carbon atoms is preferably 3 to 20, and particularly preferably 3 to 10.

[0135] R a , R b , and R c Specific examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2 1-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, 3,5,5-trimethylhexyl, n-decyl, n-undecyl, 1-methyldecyl, n-dodecyl, n-tridecyl, 1-hexylheptyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and n-eicosyl.

[0136] Examples of the group represented by formula (tR) include t-butyl, t-amyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-ethyl-1-methylbutyl, 1,1,3,3-tetramethylbutyl, 1,1,4-trimethylpentyl, 1,1,2-trimethylpropyl, 1,1-dimethyloctyl, 1,1-dimethylpentyl, 1,1-dimethylheptyl, 1,1,5-trimethylhexyl, 1-ethyl- Examples include 1-methylhexyl, 1-ethyl-1,3-dimethylbutyl, 1,1,2,2-tetramethylpropyl, 1-butyl-1-methylpentyl, 1,1-diethylbutyl, 1-ethyl-1-methylpentyl, 1,1,3-trimethylbutyl, 1-propyl-1-methylpentyl, 1,1,2-trimethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, 1-propyl-1-methylbutyl, 1,1-dimethylhexyl, etc. Among these, t-butyl and t-amyl are preferred.

[0137] The substituent is also preferably a substituent represented by formula (A30).

[0138] Cyano is also a preferred substituent. By having a cyano, which has strong electron-withdrawing properties, as a substituent in the polycyclic aromatic skeleton, a large perturbation can be imparted to the HOMO or LUMO energy, and when used as a dopant in an organic EL device, light emission with high color purity can be achieved.

[0139] The emission wavelength can be adjusted by the steric hindrance, electron donating property and electron withdrawing property of the structure of the substituent possessed by the compound used as a dopant (assisting dopant or emitting dopant). Preferred are groups represented by the following structural formulas, and more preferred are methyl, t-butyl, t-amyl, t-octyl, neopentyl, adamantyl, phenyl, o-tolyl, p-tolyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6-dimethylcarbazolyl, 3,6-di-t-butyl Preferred are methyl, t-butyl, t-amyl, t-octyl, neopentyl, adamantyl, phenyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, carbazolyl, 3,6-dimethylcarbazolyl, 3,6-di-t-butylcarbazolyl, and tribenzazepinyl. From the viewpoint of ease of synthesis, a larger steric hindrance is preferred for selective synthesis, and specifically, t-butyl, t-amyl, t-octyl, adamantyl, o-tolyl, p-tolyl, 2,4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, 3,6-dimethylcarbazolyl, and 3,6-di-t-butylcarbazolyl are preferred.

[0140] In the following structural formula, * represents a bond position. [ka]

[0141] [ka]

[0142] [ka]

[0143]

change

[0144]

change

[0145]

change

[0146]

change

[0147]

change

[0148]

change

[0149]

change

[0150]

change

[0151]

change

[0152]

change

[0153]

change

[0154] The polycyclic aromatic compound represented by formula (1) preferably has a structure containing at least one tertiary alkyl (e.g., t-butyl or t-amyl), neopentyl, or adamantyl group represented by the above-mentioned formula (tR), and preferably contains a tertiary alkyl (e.g., t-butyl or t-amyl) group represented by formula (tR). This is because such bulky substituents increase the intermolecular distance, thereby improving the luminescence quantum yield (PLQY). Diarylamino is also preferred as the substituent. Furthermore, diarylamino substituted with a group represented by formula (tR), carbazolyl (preferably N-carbazolyl) substituted with a group represented by formula (tR), or benzocarbazolyl (preferably N-benzocarbazolyl) substituted with a group represented by formula (tR) are also preferred. Examples of the substitution of a group represented by formula (tR) on diarylamino, carbazolyl, and benzocarbazolyl include those in which some or all of the hydrogen atoms on the aryl ring or benzene ring in these groups are substituted with a group represented by formula (tR).

[0155] In particular, when referring to the substituted or unsubstituted aryl rings or substituted or unsubstituted heteroaryl rings in the A, B, C, D, E, F, and G rings of the polycyclic aromatic compound represented by formula (1), the substituents in the term "substituted or unsubstituted" preferably include substituted or unsubstituted N-carbazolyl. It has been discovered that when a compound having N-carbazolyl as a substituent is used as a dopant in the light-emitting layer, organic EL devices with longer lifetimes and lower driving voltages can be obtained. It is believed that the presence of N-carbazolyl as a substituent deepens the HOMO of the compound, reducing hole trapping properties and lowering driving voltages. It is also believed that carrier recombination on the dopant is less likely to occur, making the dopant less likely to enter the T1 state, thereby extending the lifetime. Here, when N-carbazolyl has a substituent, the substituent is preferably selected from the group consisting of substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, and substituted or unsubstituted cycloalkyl. As the substituted or unsubstituted N-carbazolyl, particularly unsubstituted N-carbazolyl or 3,6-di(t-butyl)N-carbazolyl is preferred.

[0156] In the structure represented by formula (1), the substituent on the aryl ring or heteroaryl ring may be a substituent represented by the following formula (A20). [ka]

[0157] The substituent represented by formula (A20) is bonded to two adjacent atoms on the aryl ring or heteroaryl ring at two *'s, respectively. In formula (A20), L is >NR, >O, >Si(-R)2, or >S, R of the >NR is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, R of the >Si(-R)2 is hydrogen, an optionally substituted aryl, an optionally substituted alkyl, or an optionally substituted cycloalkyl, and the two R of the >Si(-R)2 may be bonded to each other to form a ring, and at least one of the R of the >NR and the >Si(-R)2 may be bonded to the aryl ring or heteroaryl ring via a linking group or a single bond. r is an integer from 1 to 4; R A are each independently hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and any R A is any other R A and may be bonded to each other via a linking group or a single bond.

[0158] Examples of the above substituent include any of the following substituents. [ka]

[0159] In each formula, * may be bonded to two or three consecutive (adjacent) atoms on any aryl or heteroaryl ring.

[0160] <Cycloalkane condensation> At least one selected from the group consisting of aryl rings and heteroaryl rings in the polycyclic aromatic compound represented by formula (1) may be condensed with at least one cycloalkane. The same applies to the structures represented by formulas (1-a) to (1-w), and the following explanation also applies to the polycyclic aromatic compounds represented by formulas (1-a) to (1-w).

[0161] The cycloalkane may be a cycloalkane having 3 to 24 carbon atoms. In this case, at least one hydrogen atom in the cycloalkane may be substituted with an aryl having 6 to 30 carbon atoms, a heteroaryl having 2 to 30 carbon atoms, an alkyl having 1 to 24 carbon atoms, or a cycloalkyl having 3 to 24 carbon atoms, and at least one -CH2- group in the cycloalkane may be replaced with -O-.

[0162] The cycloalkane is preferably a cycloalkane having 3 to 20 carbon atoms, in which at least one hydrogen atom may be substituted with an aryl having 6 to 16 carbon atoms, a heteroaryl having 2 to 22 carbon atoms, an alkyl having 1 to 12 carbon atoms, or a cycloalkyl having 3 to 16 carbon atoms.

[0163] Examples of "cycloalkane" include cycloalkanes having 3 to 24 carbon atoms, cycloalkanes having 3 to 20 carbon atoms, cycloalkanes having 3 to 16 carbon atoms, cycloalkanes having 3 to 14 carbon atoms, cycloalkanes having 5 to 10 carbon atoms, cycloalkanes having 5 to 8 carbon atoms, cycloalkanes having 5 to 6 carbon atoms, and cycloalkanes having 5 carbon atoms.

[0164] Specific examples of the cycloalkane include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, norbornane (bicyclo[2.2.1]heptane), bicyclo[1.1.0]butane, bicyclo[1.1.1]pentane, bicyclo[2.1.0]pentane, bicyclo[2.1.1]hexane, bicyclo[3.1.0]hexane, bicyclo[2.2.2]octane, adamantane, diamantane, decahydronaphthalene, and decahydroazulene, as well as alkyl (particularly methyl)-substituted, halogen (particularly fluorine)-substituted, and deuterium-substituted derivatives of these compounds having 1 to 5 carbon atoms.

[0165] Among the above examples, for example, as shown in the structural formula below, a structure having at least one substituent on the α-carbon of the cycloalkane (in a cycloalkane fused to an aryl ring or heteroaryl ring, the carbon adjacent to the carbon at the condensation site) is preferred, a structure having two substituents on the α-carbon is more preferred, and a structure having two substituents on each of the two α-carbons (four substituents in total) is even more preferred. Examples of such substituents include alkyl (particularly methyl) having 1 to 5 carbon atoms, halogen (particularly fluorine), and deuterium. In particular, a structure in which a partial structure represented by the following formula (B11) or (B12) is bonded to adjacent carbon atoms in an aryl ring or heteroaryl ring is preferred, and a structure in which a partial structure represented by the following formula (B11) is bonded is more preferred.

[0166] [ka] In formula (B11) and formula (B12), * indicates the bonding position.

[0167] The number of cycloalkanes fused to one aryl ring or heteroaryl ring is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. For example, an example in which one or more cycloalkanes are fused to one benzene ring (phenyl) is shown below. * indicates the bonding position, and the position may be any carbon that constitutes the benzene ring but not the cycloalkane. Fused cycloalkanes such as those in formula (Cy-1-4) and formula (Cy-2-4) may also be fused together. The same applies when the fused ring (group) is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), or when the fused cycloalkane is a cycloalkane other than cyclopentane or cyclohexane.

[0168] [ka]

[0169] At least one -CH2- in a cycloalkane may be replaced with -O-. For example, an example in which one or more -CH2- in a cycloalkane fused to a benzene ring (phenyl) are replaced with -O- is shown below. The same applies when the fused ring (group) is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), or when the fused cycloalkane is a cycloalkane other than cyclopentane or cyclohexane.

[0170] [ka]

[0171] The cycloalkane may be substituted with at least one substituent, and this substituent may be any substituent selected from the substituent group Z. Among these substituents, alkyl (e.g., alkyl having 1 to 6 carbon atoms) and cycloalkyl (e.g., cycloalkyl having 3 to 14 carbon atoms) are preferred. It is also preferred that any hydrogen atom is replaced with a halogen atom (e.g., fluorine) or deuterium. When substituted with cycloalkyl, the substitution may be in the form of a spiro structure. For example, an example in which a spiro structure is formed in a cycloalkane fused to one benzene ring (phenyl) is shown below. In each structural formula, * means a benzene ring included in the skeletal structure of the compound when it is a benzene ring, and means a bond substituting the skeletal structure of the compound when it is a phenyl.

[0172] [ka]

[0173] Examples of the cycloalkane condensation include a form in which the aryl rings and heteroaryl rings in each of rings A, B, C, E, G, I, J, and K in the polycyclic aromatic compound represented by formula (1) are condensed with a cycloalkane.

[0174] In another form of cycloalkane condensation, the polycyclic aromatic compound represented by formula (1) may be, for example, R NX is an aryl fused with a cycloalkane >NR NX Examples include a cycloalkane-fused diarylamino (fused to the aryl moiety), a cycloalkane-fused carbazolyl (fused to the benzene ring moiety), or a cycloalkane-fused benzocarbazolyl (fused to the benzene ring moiety).

[0175] Furthermore, by introducing a cycloalkane structure into the polycyclic aromatic compound represented by formula (1), further reductions in melting point and sublimation temperature can be expected. This means that sublimation purification, which is almost essential as a method for purifying materials for organic devices such as organic electroluminescence (EL) elements, which require high purity, can be performed at relatively low temperatures, thereby avoiding thermal decomposition of the materials. This also applies to the vacuum deposition process, which is an effective means for producing organic devices such as organic electroluminescence (EL) elements. Since the process can be performed at relatively low temperatures, thermal decomposition of the materials can be avoided, resulting in high-performance organic devices. Furthermore, the introduction of a cycloalkane structure improves solubility in organic solvents, making it possible to apply this to element fabrication using a coating process. However, the present invention is not particularly limited to these principles.

[0176] <Replacement with heavy stable isotopes> Unless otherwise specified, each element in the polycyclic aromatic compound represented by formula (1) contains multiple naturally occurring isotopes in their natural abundance ratios. However, all or some of the elements in each structural formula may contain heavy stable isotopes in excess of their natural abundance ratios (for example, boron-11 (11B) at 90 atom % or more). In this specification, this is simply referred to as "replacement" with a "heavy stable isotope." More specifically, at least one hydrogen can be replaced with deuterium, and at least one nitrogen can be replaced with nitrogen-15 ( 15 N), and at least one sulfur can be replaced by sulfur-33 ( 33 S), sulfur-34(34 S) or sulfur-36( 36 S), and at least one oxygen can be replaced by oxygen-17( 17 O) or oxygen-18( 18 O), and at least one carbon can be replaced by carbon-13 ( 13 C), and at least one boron can be replaced by boron-11 ( 11 B). The same applies to the structures represented by formulas (1-a) to (1-w), and the following explanation also applies to the polycyclic aromatic compounds represented by formulas (1-a) to (1-w). By replacing at least some elements with heavy stable isotopes, in particular, at least one boron can be replaced with boron-11( 11 By replacing with B), it is possible to extend the life of an organic electroluminescent device using the polycyclic aromatic compound represented by formula (1) as a dopant.

[0177] For example, in the polycyclic aromatic compound represented by formula (1), hydrogen atoms in rings A, B, C, D, F, G, H, I, and e, and in the substituents thereof, can be replaced with deuterium atoms, and among these, embodiments in which all or part of the hydrogen atoms in aryls and heteroaryls are replaced with deuterium atoms are exemplified. From the viewpoint of durability, it is also preferable that all or part of the hydrogen atoms in the polycyclic aromatic compound represented by formula (1) are deuterated.

[0178] <Specific examples of polycyclic aromatic compounds> Examples of the polycyclic aromatic compound represented by formula (1) include compounds represented by any of the following structural formulas. [ka]

[0179] [ka]

[0180] [ka]

[0181]

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[0182]

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[0183]

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[0184]

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[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0199]

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[0200]

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[0201]

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[0202] [ka]

[0203] <Method of producing polycyclic aromatic compounds> The polycyclic aromatic compound represented by formula (1) can be synthesized by first synthesizing a starting material having one boron atom (first reaction), then introducing two boron atoms to synthesize an intermediate having three boron atoms (second reaction), and then introducing two more boron atoms to synthesize a compound of formula (1) having five boron atoms (third reaction). The bonding group (nitrogen atom and X) in the synthesis of the starting material for the first reaction 1 and X 2 For example, common reactions such as nucleophilic substitution and the Ullmann reaction can be used for etherification, and common reactions such as the Buchwald-Hartwig reaction, nucleophilic substitution, and the Goldberg amination can be used for amination.

[0204] Furthermore, in the first to third reactions for introducing boron, a tandem hetero-Friedel-Crafts reaction (sequential aromatic electrophilic substitution reaction, the same applies hereinafter) can be used. The following intermediate having three boron atoms in the second reaction can be synthesized, for example, by the method described in JP-A-2023-114978.

[0205] In the third reaction, two more boron atoms are introduced. As shown in the following scheme (1), intermediate-1 is reacted with a boron reagent such as boron tribromide or boron triiodide, followed by the addition of a Brønsted base such as 2,6-tert-butylpyridine to obtain the target compound represented by formula (1). Alternatively, as shown in the following scheme (2), the halogen atoms of intermediate-2 are metallated by reacting with an organometallic reagent such as t-butyllithium, followed by the addition of a boron reagent such as boron trichloride, boron tribromide, or boron triiodide to perform a boron-metal exchange reaction, followed by the addition of a Brønsted base to proceed with a tandem boron-Friedel-Crafts reaction to obtain the target compound represented by formula (1).

[0206] [ka]

[0207] By appropriately selecting the raw materials to be used, it is possible to synthesize a polycyclic aromatic compound having substituents at desired positions.

[0208] In the third reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction. Furthermore, the halogen atom Cl in the formula of intermediate-2 in scheme (2) may be F, Br, or I, and the halogen atom can be appropriately selected taking into consideration the reactivity of the substrate.

[0209] Specific examples of the solvent used in the above reaction include chlorobenzene, o-dichlorobenzene, t-butylbenzene, xylene, and the like.

[0210] Examples of the reagent used in the above scheme (2) include alkyllithiums such as methyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium; organic alkali metal compounds such as lithium diisopropylamide, lithium tetramethylpiperidide, lithium hexamethyldisilazide, and potassium hexamethyldisilazide; and alkali metals such as lithium, sodium, and potassium.

[0211] Examples of the boron reagent used in the above schemes (1) and (2) include boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide, boron alkoxylates, and boron aryloxylates.

[0212] Examples of the Bronsted base used in the above schemes (1) and (2) include 2,6-di-tert-butylpyridine, 2,4,6-tris-tert-butylpyridine, 2,6-lutidine, N,N-diisopropylethylamine, triethylamine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2,6-lutidine, sodium tetraphenylborate, potassium tetraphenylborate, triphenylborane, tetraphenylsilane, ArBNa, ArBK, ArB, and ArSi (wherein Ar is an aryl such as phenyl).

[0213] Examples of Lewis acids used in the above schemes (1) and (2) include AlCl3, AlBr3, AlF3, BF3·OEt2, BCl3, BBr3, BI3, GaCl3, GaBr3, InCl3, InBr3, In(OTf)3, SnCl4, SnBr4, AgOTf, ScCl3, Sc(OTf)3, ZnCl2, ZnBr2, Zn(OTf)2, MgCl2, MgBr2, Mg(OTf)2, LiOTf, NaOTf, KOTf, Me3SiOTf, Cu(OTf)2, CuCl2, YCl3, Y(OTf)3, TiCl4, TiBr4, ZrCl4, ZrBr4, FeCl3, FeBr3, CoCl3, and CoBr3.

[0214] In the above scheme (2), a Brønsted base or Lewis acid may be used to promote the tandem hetero-Friedel-Crafts reaction. However, when using boron halides such as boron trifluoride, boron trichloride, boron tribromide, or boron triiodide, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide are generated as the aromatic electrophilic substitution reaction proceeds, so the use of a Brønsted base to capture the acid is effective. On the other hand, when using boron amination halides or boron alkoxides, amines and alcohols are generated as the aromatic electrophilic substitution reaction proceeds, so the use of a Brønsted base is often unnecessary. However, because the amino and alkoxy groups have low elimination ability, the use of a Lewis acid to promote their elimination is effective.

[0215] The polycyclic aromatic compounds of the present invention also include those in which at least some of the hydrogen atoms are substituted with deuterium or with halogens such as fluorine or chlorine. Such compounds can be synthesized in the same manner as described above by using raw materials in which the desired positions are deuterated, fluorinated, or chlorinated.

[0216] 2. Organic Devices The polycyclic aromatic compound of the present invention can be used as a material for organic devices. Examples of organic devices include organic electroluminescent devices, organic field-effect transistors, and organic thin-film solar cells. The polycyclic aromatic compound of the present invention is preferably used as a material for forming one or more organic layers in the organic electroluminescent devices.

[0217] 2-1. Organic electroluminescent device 2-1-1. Structure of organic electroluminescent device FIG. 1 is a schematic cross-sectional view showing an example of an organic EL element. The organic EL device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, a hole transport layer 104 provided on the hole injection layer 103, an emitting layer 105 provided on the hole transport layer 104, an electron transport layer 106 provided on the emitting layer 105, an electron injection layer 107 provided on the electron transport layer 106, and a cathode 108 provided on the electron injection layer 107.

[0218] The organic EL element 100 may be fabricated in the reverse order, for example, to have a substrate 101, a cathode 108 provided on the substrate 101, an electron injection layer 107 provided on the cathode 108, an electron transport layer 106 provided on the electron injection layer 107, an emitting layer 105 provided on the electron transport layer 106, a hole transport layer 104 provided on the emitting layer 105, a hole injection layer 103 provided on the hole transport layer 104, and an anode 102 provided on the hole injection layer 103.

[0219] Not all of the above layers are essential, and the minimum structural unit is a configuration consisting of an anode 102, an emitting layer 105, and a cathode 108. The hole injection layer 103, the hole transport layer 104, the electron transport layer 106, and the electron injection layer 107 are layers that may be optionally provided. Furthermore, each of the above layers may consist of a single layer or multiple layers.

[0220] The layers constituting the organic EL element may be configured as follows: "substrate / anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode" as described above, as well as "substrate / anode / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode", "substrate / anode / hole injection layer / light-emitting layer / electron transport layer / electron injection layer / cathode", "substrate / anode / hole injection layer / hole transport layer / light-emitting ... transport The configuration may be, for example, "substrate / anode / light-emitting layer / electron transport layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole transport layer / light-emitting layer / electron transport layer / cathode," "substrate / anode / hole injection layer / light-emitting layer / electron injection layer / cathode," "substrate / anode / hole injection layer / light-emitting layer / electron transport layer / cathode," "substrate / anode / light-emitting layer / electron transport layer / cathode," or "substrate / anode / light-emitting layer / electron injection layer / cathode."

[0221] The organic EL device may further include one or both of an electron blocking layer (electron blocking layer) and a hole blocking layer (hole blocking layer). The electron blocking layer has a LUMO shallower than that of the light-emitting layer and a HOMO close to that of the light-emitting layer or the hole transport layer, and is disposed between the light-emitting layer and the hole transport layer. Since electrons remain in the light-emitting layer and do not leak into the hole transport layer, it is possible to prevent a shortened lifetime due to deterioration of the hole transport layer and a decrease in efficiency due to a decrease in recombination efficiency. The hole blocking layer has a HOMO deeper than that of the light-emitting layer and a LUMO close to that of the light-emitting layer or the hole transport layer, and is disposed between the light-emitting layer and the electron transport layer. Since holes remain in the light-emitting layer and do not leak into the electron transport layer, it is possible to prevent a shortened lifetime due to deterioration of the electron transport layer and a decrease in efficiency due to a decrease in recombination efficiency. The hole injection / transport layer may also function as the electron blocking layer. The electron injection / transport layer may also function as the hole blocking layer.

[0222] The organic EL device may further include a high T1 layer. The high T1 layer has a higher T1 than the host compound, assisting dopant compound, or emitting dopant compound used in the emissive layer, and is disposed between the emissive layer and the hole-transporting layer and / or between the emissive layer and the electron-blocking layer. The T1 energy value varies depending on the device's light-emitting mechanism, but it has a higher T1 than the compound used in the host. By having a high T1 layer around the emissive layer, triplet energy can be trapped and converted into singlet energy, which would not normally lead to light emission in fluorescent molecules, resulting in high efficiency. The hole-injection / transporting layer or electron-blocking layer may also function as a high T1 layer. The electron-injection / transporting layer or hole-blocking layer may also function as a high T1 layer.

[0223] The polycyclic aromatic compound of the present invention is preferably used as a material for forming a light-emitting layer or a material for forming an electron transport layer, and more preferably as a material for forming a light-emitting layer. The polycyclic aromatic compound of the present invention is particularly preferably used as a green light-emitting material.

[0224] 2-1-2. Substrate in organic electroluminescent device The substrate 101 is a support for the organic EL device 100 and is typically made of quartz, glass, metal, plastic, or the like. The substrate 101 may be formed into a plate, film, or sheet shape depending on the purpose, and may be, for example, a glass plate, a metal plate, a metal foil, a plastic film, or a plastic sheet. Among these, glass plates and plates made of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. For glass substrates, soda-lime glass or alkali-free glass may be used, and the thickness may be sufficient to maintain mechanical strength. Furthermore, to improve gas barrier properties, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one side. Providing a gas barrier film is particularly preferred when a synthetic resin plate, film, or sheet with poor gas barrier properties is used as the substrate 101.

[0225] 2-1-3. Anode in organic electroluminescent device The anode 102 serves to inject holes into the light-emitting layer 105. When at least one of the hole injection layer 103 and the hole transport layer 104 is provided between the anode 102 and the light-emitting layer 105, holes are injected into the light-emitting layer 105 via these layers.

[0226] Materials for forming the anode 102 include inorganic and organic compounds. Examples of inorganic compounds include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO), etc.), metal halides (copper iodide, etc.), copper sulfide, carbon black, ITO glass, and NESA glass. Examples of organic compounds include polythiophenes such as poly(3-methylthiophene), and conductive polymers such as polypyrrole and polyaniline. In addition, materials can be appropriately selected from those used as anodes in organic EL devices.

[0227] 2-1-4. Hole injection layer and hole transport layer in organic electroluminescent device The hole injection layer 103 serves to efficiently inject holes migrating from the anode 102 into the light-emitting layer 105 or the hole transport layer 104. The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 via the hole injection layer 103 to the light-emitting layer 105. The hole injection layer 103 and the hole transport layer 104 are each formed by laminating or mixing one or more types of hole injection / transport materials. Alternatively, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injection / transport material.

[0228] A hole injection / transport material must be able to efficiently inject and transport holes from the positive electrode between electrodes to which an electric field is applied, and it is desirable for the material to have high hole injection efficiency and efficiently transport the injected holes. To achieve this, it is desirable for the material to have a low ionization potential, high hole mobility, excellent stability, and be less likely to generate impurities that act as traps during production and use.

[0229] As materials for forming the hole injection layer 103 and the hole transport layer 104, any compound can be selected from compounds conventionally used as charge transport materials for holes in photoconductive materials, p-type semiconductors, and known compounds used in hole injection layers and hole transport layers of organic EL devices. Specific examples thereof include carbazole derivatives (N-phenylcarbazole, polyvinylcarbazole, etc.), biscarbazole derivatives such as bis(N-arylcarbazole) or bis(N-alkylcarbazole), triarylamine derivatives (polymers having an aromatic tertiary amino group in the main chain or side chain, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'-diphenyl-1,1'-diamine, N 4 ,N 4’ -diphenyl-N 4 ,N 4’ -bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N 4 ,N 4 ,N 4’ ,N 4’-Triphenylamine derivatives such as tetra([1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives Examples of the material include conductors (for example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. Among polymers, polycarbonates and styrene derivatives having the above-mentioned monomers in their side chains, polyvinylcarbazole, and polysilanes are preferred, but there are no particular limitations on the material as long as it is a compound that can form a thin film required for fabricating a light-emitting device, can inject holes from the anode, and can transport holes.

[0230] It is also known that the conductivity of organic semiconductors is strongly influenced by their doping. Such organic semiconductor matrix materials consist of compounds with good electron-donating or electron-accepting properties. Strong electron acceptors such as tetracyanoquinone dimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinone dimethane (F4TCNQ) are known for doping with electron-donating substances (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes via an electron transfer process in the electron-donating base material (hole-transporting material). The conductivity of the base material varies considerably depending on the number and mobility of holes. Known matrix materials with hole transport properties include benzidine derivatives (such as TPD) or starburst amine derivatives (such as TDATA), as well as certain metal phthalocyanines (e.g., zinc phthalocyanine (ZnPc)) (see JP 2005-167175 A).

[0231] The hole injection layer material and the hole transport layer material described above can also be used as hole layer materials in the form of a polymer compound obtained by polymerizing a reactive compound substituted with a reactive substituent as a monomer, or a crosslinked polymer thereof, or a pendant polymer compound obtained by reacting a main-chain polymer with the reactive compound, or a crosslinked pendant polymer thereof.

[0232] 2-1-5. Emitting layer in organic electroluminescent device The light-emitting layer 105 is a layer that emits light by recombining holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material that forms the light-emitting layer 105 may be a compound that emits light when excited by the recombination of holes and electrons (a light-emitting compound), and a compound that can be formed into a stable thin film and that exhibits strong luminescence (fluorescence) efficiency in a solid state is preferably used.

[0233] The light-emitting layer may be a single layer or multiple layers, each of which is formed from a material for a light-emitting layer. When the light-emitting layer is multiple layers, it is preferable that any one of the layers contains the polycyclic aromatic compound of the present invention. It is preferable that the light-emitting layer is a single layer.

[0234] The light-emitting layer is formed from materials for the light-emitting layer (host material, dopant material). The host material and the dopant material may each be one type or a combination of two or more types. For example, an emitting dopant and an assisting dopant may be used as the dopant material. The light-emitting layer also preferably contains an emitting dopant and at least two materials selected from the group consisting of a hole-transporting host material, an electron-transporting host material, and an assisting dopant material. The dopant material may be contained entirely or partially in the host material. The doping method can be a co-evaporation method with the host material, or the dopant material may be mixed with the host material and then vapor-deposited simultaneously. The light-emitting layer can also be formed by a wet film-forming method using a light-emitting layer-forming composition prepared by dissolving the material in an organic solvent.

[0235] The amount of the host material used varies depending on the type of host material and may be determined according to the properties of the host material. The amount of the host material used is preferably 50 to 99.999% by mass, more preferably 80 to 99.95% by mass, and even more preferably 90 to 99.9% by mass, of the total mass of the materials for the light-emitting layer. When the host material is a combination of a hole-transporting host material and an electron-transporting host material, the amount of the host material used is the combined mass of the hole-transporting host material and the electron-transporting host material. The ratio of the amount of the hole-transporting host material to the amount of the electron-transporting host material used may be 1:9 to 9:1 by mass, preferably 4:6 to 6:4, and more preferably approximately 1:1.

[0236] The amount of the emitting dopant used varies depending on the type of emitting dopant and may be determined according to its properties. The amount of the emitting dopant used is preferably 0.001 to 50% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass, of the total mass of the materials for the light-emitting layer. The above range is preferable in that, for example, concentration quenching can be prevented.

[0237] In organic electroluminescent devices that use an assisting dopant (thermally activated delayed fluorescent material or phosphorescent material) in addition to an emitting dopant, a low concentration of the emitting dopant material is preferred in terms of preventing concentration quenching. A high concentration of the assisting dopant is preferred in terms of energy transfer efficiency. A high concentration of the assisting dopant is preferred in terms of efficiency of the thermally activated delayed fluorescence mechanism. In organic electroluminescent devices that use a thermally activated delayed fluorescent material as the assisting dopant, a low concentration of the emitting dopant is preferred compared to the assisting dopant in terms of efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant.

[0238] When an assisting dopant material is used, the amounts of the host material, assisting dopant material, and emitting dopant material used are approximately 40 to 99% by mass, 59 to 1% by mass, and 20 to 0.001% by mass, respectively, based on the total mass of the materials for the light-emitting layer, preferably 60 to 95% by mass, 39 to 5% by mass, and 10 to 0.01% by mass, respectively, and more preferably 70 to 90% by mass, 29 to 10% by mass, and 5 to 0.05% by mass.

[0239] The polycyclic aromatic compound represented by formula (1) is preferably used as a material for forming a light-emitting layer, more preferably as a dopant, and particularly preferably as an emitting dopant.

[0240] The polycyclic aromatic compound represented by formula (1) can be used as an emitting dopant in a TTF device that utilizes the phenomenon of triplet-triplet fusion (TTF), in which a singlet exciton is generated from multiple triplet excitons.

[0241] Furthermore, the polycyclic aromatic compound represented by formula (1) can be used as an emitting dopant in TADF devices as a "thermally activated delayed fluorescent material." By reducing the energy difference between the lowest excited singlet state and the lowest excited triplet state, a "thermally activated delayed fluorescent material" efficiently induces reverse intersystem crossing from the lowest excited triplet state, which normally has a low transition probability, to the lowest excited singlet state, resulting in emission from the singlet state (thermally activated delayed fluorescent material, TADF). In conventional fluorescent emission, 75% of the triplet excitons generated by current excitation undergo a thermal deactivation pathway and cannot be extracted as fluorescence. In contrast, TADF allows all excitons to be utilized for fluorescent emission, enabling the realization of highly efficient organic electroluminescent devices.

[0242] Generally, a material with a faster delayed fluorescence is considered to have better TADF properties. Specifically, when a light-emitting material with a delayed fluorescence lifetime of 100 μsec or less is used as an emitting dopant in a light-emitting device, it can provide high device efficiency and a long device lifetime. The delayed fluorescence lifetime is preferably 20 μsec or less, more preferably less than 20 μsec, even more preferably 10 μsec or less, and most preferably 5 μsec or less.

[0243] Also, generally, ΔE S1T1 The smaller the value, the better the TADF properties. S1T1 is the lowest excited singlet energy level (E S1 ) and the lowest excited triplet energy level (E T1 ) is the energy difference between the S1T1 The value is preferably 0.20 eV or less, more preferably 0.15 eV or less, and particularly preferably 0.10 eV or less.

[0244] In addition, the polycyclic aromatic compound represented by formula (1) can also be applied to a TPSF (phosphor-assisted thermally activated delayed fluorophore-sensitized fluorescence) element, which uses a "thermally activated delayed fluorescent substance" as a host and a phosphorescent material as an assisting dopant.

[0245] <Host material> Examples of host materials include fused ring derivatives of anthracene, pyrene, and the like, which have long been known as light emitters; bisstyryl derivatives such as bisstyryl anthracene derivatives and distyrylbenzene derivatives; tetraphenylbutadiene derivatives; cyclopentadiene derivatives; fluorene derivatives; benzofluorene derivatives; N-phenylcarbazole derivatives; carbazonitrile derivatives; and dibenzochrysene derivatives. From the viewpoint of durability, it is also preferable that some or all of the hydrogen atoms in the host material are deuterated. Furthermore, it is also preferable to form an emitting layer by combining a host compound in which some or all of the hydrogen atoms are deuterated with a dopant compound in which some or all of the hydrogen atoms are deuterated.

[0246] The host material may be one kind or a combination of two or more kinds. In the case of a combination of two or more kinds, a combination of a hole-transporting host material and an electron-transporting host material is preferred.

[0247] [Anthracene compounds] Examples of the anthracene compound as a host include a compound represented by formula (3-H) and a compound represented by formula (3-H2). [ka]

[0248] In formula (3-H), X and Ar 4 are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino, optionally substituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino, substituted or unsubstituted alkyl, optionally substituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted arylthio, or substituted silyl; and all of X and Ar 4 cannot simultaneously become hydrogen. At least one hydrogen atom in the compound represented by formula (3-H) may be substituted with halogen, cyano, deuterium, or an optionally substituted heteroaryl.

[0249] Furthermore, a multimer (preferably a dimer) may be formed using the structure represented by formula (3-H) as a unit structure. In this case, for example, the unit structures represented by formula (3-H) may be bonded to each other via X, where X may be a single bond, an arylene (such as phenylene, biphenylene, or naphthylene), or a heteroarylene (a divalent group such as a pyridine ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a benzocarbazole ring, or a phenyl-substituted carbazole ring).

[0250] For details of each group in the compound represented by formula (3-H), the explanation for formula (1) above can be cited, and further explanation will be given in the section on preferred embodiments below.

[0251] Preferred embodiments of the above anthracene compounds are described below: The symbols in the following structures are defined as above. [ka]

[0252] In formula (3-H), X's are each independently a group represented by formula (3-X1), formula (3-X2), or formula (3-X3), and the group represented by formula (3-X1), formula (3-X2), or formula (3-X3) is bonded to the anthracene ring of formula (3-H) at *. Preferably, no two X's are simultaneously a group represented by formula (3-X3). More preferably, no two X's are simultaneously a group represented by formula (3-X2).

[0253] Furthermore, a multimer (preferably a dimer) may be formed using the structure represented by formula (3-H) as a unit structure. In this case, for example, the unit structures represented by formula (3-H) may be bonded to each other via X, where X may be a single bond, an arylene (such as phenylene, biphenylene, or naphthylene), or a heteroarylene (a divalent group such as a pyridine ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a benzocarbazole ring, or a phenyl-substituted carbazole ring).

[0254] The naphthylene moieties in formula (3-X1) and formula (3-X2) may be fused with one benzene ring. The fused structures are as follows: [ka]

[0255] Ar 1 and Ar 2 are each independently hydrogen, phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) (including carbazolyl, benzocarbazolyl, and phenyl-substituted carbazolyl). 1 or Ar 2 is a group represented by formula (A), the group represented by formula (A) is bonded to the naphthalene ring in formula (3-X1) or formula (3-X2) at the *.

[0256] Ar 3 is phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) (including carbazolyl, benzocarbazolyl, and phenyl-substituted carbazolyl). 3is a group represented by formula (A), the group represented by formula (A) is bonded to the single bond represented by a straight line in formula (3-X3) at the *. That is, the anthracene ring of formula (3-H) and the group represented by formula (A) are directly bonded.

[0257] Also, Ar 3 may have a substituent, and Ar 3 At least one hydrogen atom in the formula (A) may be further substituted with an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A) (including carbazolyl and phenyl-substituted carbazolyl). 3 When the substituent of is a group represented by formula (A), the group represented by formula (A) is Ar in formula (3-X3) at *. 3 and combine.

[0258] Ar 4 are each independently hydrogen, phenyl, biphenylyl, terphenylyl, naphthyl, or silyl substituted with alkyl having 1 to 4 carbon atoms (such as methyl, ethyl, and t-butyl) and / or cycloalkyl having 5 to 10 carbon atoms.

[0259] Examples of the alkyl having 1 to 4 carbon atoms that substitutes on the silyl include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl, and cyclobutyl, and three hydrogen atoms on the silyl are each independently substituted with these alkyls.

[0260] Specific examples of "silyl substituted with alkyl having 1 to 4 carbon atoms" include trimethylsilyl, triethylsilyl, tripropylsilyl, triisopropylsilyl, tributylsilyl, tri-sec-butylsilyl, tri-t-butylsilyl, ethyldimethylsilyl, propyldimethylsilyl, isopropyldimethylsilyl, butyldimethylsilyl, sec-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, propyldiethylsilyl, isopropyldiethylsilyl, butyldiethylsilyl, sec-butyldiethylsilyl, t-butyldiethylsilyl, methyldipropylsilyl, ethyldipropylsilyl, butyldipropylsilyl, sec-butyldipropylsilyl, t-butyldipropylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, butyldiisopropylsilyl, sec-butyldiisopropylsilyl, t-butyldiisopropylsilyl, and the like.

[0261] Examples of the cycloalkyl having 5 to 10 carbon atoms substituting the silyl include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclo[1.1.1]pentyl, bicyclo[2.1.0]pentyl, bicyclo[2.1.1]hexyl, bicyclo[3.1.0]hexyl, bicyclo[2.2.1]heptyl (norbornyl), bicyclo[2.2.2]octyl, adamantyl, decahydronaphthalenyl, and decahydroazulenyl, and three hydrogen atoms in the silyl are each independently substituted with one of these cycloalkyls.

[0262] Specific examples of "silyl substituted with cycloalkyl having 5 to 10 carbon atoms" include tricyclopentylsilyl and tricyclohexylsilyl.

[0263] Substituted silyls include dialkylcycloalkylsilyls, which are substituted with two alkyls and one cycloalkyl, and alkyldicycloalkylsilyls, which are substituted with one alkyl and two cycloalkyls. Specific examples of the alkyl and cycloalkyl substituents are the groups described above.

[0264] Furthermore, hydrogen atoms in the chemical structure of the anthracene compound represented by formula (3-H) may be substituted with a group represented by formula (A). When substituted with a group represented by formula (A), the group represented by formula (A) replaces at least one hydrogen atom in the compound represented by formula (3-H) at the *.

[0265] The group represented by formula (A) is one of the substituents that the anthracene compound represented by formula (3-H) may have. [ka]

[0266] In formula (A), Y is —O—, —S—, or >NR 29 and R 21 ~R 28 are each independently hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted arylthio, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, optionally substituted amino, halogen, hydroxy or cyano; R 21 ~R 28 adjacent groups among R may be bonded to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring; 29 is hydrogen or optionally substituted aryl. In formula (A), Y is preferably —O—.

[0267] R 21 ~R 28Among these, adjacent groups may be bonded to each other to form a hydrocarbon ring, an aryl ring, or a heteroaryl ring. The group represented by formula (A-1) below does not form a ring, and examples of the group represented by formulas (A-2) to (A-14) below include groups represented by formulas (A-1) to (A-14). At least one hydrogen atom in the group represented by any of formulas (A-1) to (A-14) may be substituted with alkyl, cycloalkyl, aryl, heteroaryl, alkoxy, aryloxy, arylthio, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, alkyldicycloalkylsilyl, diaryl (the two aryls may be bonded to each other via a linking group), substituted amino, diheteroaryl-substituted amino, arylheteroaryl-substituted amino, halogen, hydroxy, or cyano.

[0268] [ka]

[0269] Examples of rings formed by bonding adjacent groups to each other include hydrocarbon rings such as cyclohexane rings, and examples of aryl and heteroaryl rings include the above-mentioned R 21 ~R 28 These rings are formed so as to be fused with one or two benzene rings in formula (A-1).

[0270] The group represented by formula (A) is a group obtained by removing one hydrogen atom from any position of formula (A), and * indicates the position. That is, the group represented by formula (A) may have any position as a bonding position. For example, any carbon atom on the two benzene rings in the structure of formula (A), R 21 ~R 28 An atom on any ring formed by bonding adjacent groups to each other, or ">NR 29 "R" 29 Any position in the 29 " in N(R29 The same applies to the groups represented by any of formulae (A-1) to (A-14).

[0271] Examples of the group represented by formula (A) include groups represented by any of formulas (A-1) to (A-14), preferably groups represented by any of formulas (A-1) to (A-5) and formulas (A-12) to (A-14), more preferably groups represented by any of formulas (A-1) to (A-4), still more preferably groups represented by any of formulas (A-1), (A-3) and (A-4), and particularly preferably groups represented by formula (A-1).

[0272] Examples of the group represented by formula (A) include the following groups: In the formula, Y and * are defined as above. [ka]

[0273] [ka]

[0274] In the compound represented by formula (3-H), the group represented by formula (A) is a naphthalene ring in formula (3-X1) or formula (3-X2), a single bond in formula (3-X3), and Ar in formula (3-X3). 3 The preferred form is a combination of any one of the following:

[0275] All or part of the hydrogen atoms in the chemical structure of the anthracene compound represented by formula (3-H) may be deuterium atoms.

[0276] The anthracene compound as the host may be, for example, a compound represented by the following formula (3-H2). [ka]

[0277] In formula (3-H2), Ar c is an optionally substituted aryl or an optionally substituted heteroaryl, and R c is hydrogen, alkyl, or cycloalkyl, and Ar 11 , Ar 12 , Ar 13 , Ar 14 , Ar 15 , Ar 16 , Ar 17 , and Ar 18 are each independently hydrogen, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted diarylamino, optionally substituted diheteroarylamino, optionally substituted arylheteroarylamino, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted arylthio, or optionally substituted silyl, and at least one hydrogen in the compound represented by formula (3-H2) may be substituted with halogen, cyano, or deuterium.

[0278] In formula (3-H2), the definitions of "optionally substituted aryl," "optionally substituted heteroaryl," "optionally substituted diarylamino," "optionally substituted diheteroarylamino," "optionally substituted arylheteroarylamino," "optionally substituted alkyl," "optionally substituted cycloalkyl," "optionally substituted alkenyl," "optionally substituted alkoxy," "optionally substituted aryloxy," "optionally substituted arylthio," and "optionally substituted silyl" are the same as those shown in formula (3-H) above, and the explanation in formula (3-H) can be cited.

[0279] The "optionally substituted aryl" is also preferably a group represented by any one of the following formulae (3-H2-X1) to (3-H2-X8).

[0280] [ka]

[0281] In formulae (3-H2-X1) to (3-H2-X8), * indicates a bonding position. In formulae (3-H2-X1) to (3-H2-X3), Ar 21 , Ar 22 , and Ar 23 are each independently hydrogen, phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, anthracenyl, or a group represented by formula (A). In the description of formula (3-H2), the group represented by formula (A) is the same as that described in the anthracene compound represented by formula (3-H).

[0282] In the formulas (3-H2-X4) to (3-H2-X8), Ar 24 , Ar 25 , Ar 26 , Ar 27 , Ar 28 , Ar 29 , and Ar 30 are each independently hydrogen, phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A). In addition, any one or more hydrogen atoms in each of the groups represented by formulas (3-H2-X1) to (3-H2-X8) may be substituted with alkyl having 1 to 6 carbon atoms (preferably methyl or t-butyl).

[0283] Furthermore, preferred examples of the "optionally substituted aryl" include terphenylyl (particularly m-terphenyl-5'-yl) optionally substituted with one or more substituents selected from the group consisting of phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, chrysenyl, triphenylenyl, pyrenyl, and groups represented by formula (A).

[0284] The "optionally substituted heteroaryl" also includes a group represented by formula (A). Other specific examples of the "optionally substituted aryl" and "optionally substituted heteroaryl" include dibenzofuryl, naphthobenzofuryl, phenyl-substituted dibenzofuryl, etc.

[0285] At least one hydrogen atom in the compound represented by formula (3-H2) may be substituted with a halogen atom, cyano atom, or deuterium atom. In this case, "halogen" includes fluorine, chlorine, bromine, and iodine. In particular, a compound in which all hydrogen atoms in the compound represented by formula (3-H2) are substituted with deuterium atoms is preferred.

[0286] In formula (3-H2), R c is hydrogen, alkyl, or cycloalkyl, preferably hydrogen, methyl, or t-butyl, and more preferably hydrogen. In formula (3-H2), Ar 11 ~Ar 18 It is preferable that at least two of the substituents be optionally substituted aryl or optionally substituted heteroaryl. That is, the anthracene compound represented by formula (3-H2) preferably has a structure in which at least three substituents selected from the group consisting of optionally substituted aryl and optionally substituted heteroaryl are bonded to the anthracene ring.

[0287] The anthracene compound represented by formula (3-H2) is Ar 11 ~Ar 18It is more preferred that two of the groups are optionally substituted aryl or optionally substituted heteroaryl, and the other six are hydrogen, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, or optionally substituted alkoxy. That is, it is more preferred that the anthracene compound represented by formula (3-H2) has a structure in which three substituents selected from the group consisting of optionally substituted aryl and optionally substituted heteroaryl are bonded to the anthracene ring.

[0288] The anthracene compound represented by formula (3-H2) is Ar 11 ~Ar 18 It is more preferred that any two of are optionally substituted aryl or optionally substituted heteroaryl, and the other six are hydrogen, methyl, or t-butyl.

[0289] Furthermore, in formula (3-H2), R c is hydrogen and Ar 11 ~Ar 18 It is preferred that any six of these are hydrogen.

[0290] The anthracene compound represented by formula (3-H2) is preferably an anthracene compound represented by the following formula (3-H2-A), (3-H2-B), (3-H2-C), (3-H2-D), or (3-H2-E). [ka]

[0291] In formula (3-H2-A), (3-H2-B), (3-H2-C), (3-H2-D) or (3-H2-E), Ar c ', Ar 11 ', Ar 12 ', Ar 13 ', Ar 14 ', Ar 15 ', Ar 17 ', and Ar 18Each of the ' is independently phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A), and at least one hydrogen atom in these groups may be substituted with phenyl, biphenylyl, terphenylyl, quaterphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by formula (A). When both hydrogen atoms of the methylenes in the fluorenyl and benzofluorenyl are substituted with phenyl, these phenyls may be bonded to each other via a single bond. Ar c ', Ar 11 ', Ar 12 ', Ar 13 ', Ar 14 ', Ar 15 ', Ar 17 ', and Ar 18 The carbon atoms of the anthracene ring to which ' is not attached may have methyl or t-butyl attached instead of hydrogen.

[0292] Ar c ', Ar 11 ', Ar 12 ', Ar 13 ', Ar 14 ', Ar 15 ', Ar 17 ', and Ar 18 When each of "3-H2-X1" and "3-H2-X8" is a substituted or unsubstituted phenyl or a substituted or unsubstituted naphthyl, it is preferably a group represented by any one of the above formulae (3-H2-X1) to (3-H2-X8).

[0293] Ar c ', Ar 11 ', Ar 12 ', Ar 13 ', Ar 14 ', Ar 15 ', Ar 17 ', and Ar 18It is more preferable that each of the ' is independently phenyl, biphenylyl (particularly biphenyl-2-yl or biphenyl-4-yl), terphenylyl (particularly m-terphenyl-5'-yl), naphthyl, phenanthryl, fluorenyl, or a group represented by any one of the above formulas (A-1) to (A-4), and in this case, at least one hydrogen atom in these groups may be substituted by phenyl, biphenylyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of the above formulas (A-1) to (A-4).

[0294] In addition, at least one hydrogen atom in the compound represented by formula (3-H2-A), (3-H2-B), (3-H2-C), (3-H2-D), or (3-H2-E) may be replaced with a halogen atom, a cyano atom, or a deuterium atom. Deuterated forms are preferred, and a form in which all anthracene rings are deuterated or a form in which all hydrogen atoms are deuterated is preferred.

[0295] Particularly preferred anthracene compounds represented by formula (3-H2) include anthracene compounds represented by the following formula (3-H2-Aa). [ka]

[0296] In formula (3-H2-Aa), Ar c ', Ar 14 ', and Ar 15Each of the ' is independently phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by any one of the above formulas (A-1) to (A-11), and at least one hydrogen atom in these groups may be substituted with phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, benzofluorenyl, chrysenyl, triphenylenyl, pyrenyl, or a group represented by any one of the formulas (A-1) to (A-11). When both hydrogen atoms of the methylenes in the fluorenyl and benzofluorenyl are substituted with phenyl, these phenyls may be bonded to each other via a single bond. In addition, Ar c ', Ar 14 ', and Ar 15 A carbon atom on the anthracene ring to which "'" is not bonded may be substituted with methyl or t-butyl in place of hydrogen. At least one hydrogen in the compound represented by formula (3-H2-Aa) may be substituted with halogen or cyano, and at least one hydrogen in the compound represented by formula (3-H2-Aa) is substituted with deuterium.

[0297] In formula (3-H2-Aa), Ar c ', Ar 14 ', and Ar 15 It is preferable that each of the ' is independently phenyl, biphenylyl, terphenylyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of the above formulas (A-1) to (A-4), and at least one hydrogen in these groups may be substituted by phenyl, naphthyl, phenanthryl, fluorenyl, or a group represented by any one of the above formulas (A-1) to (A-4).

[0298] In the compound represented by formula (3-H2-Aa), at least the carbon atom at the 10-position of the anthracene ring (Ar cIt is preferable that the hydrogen bonded to the carbon atom (the carbon atom to which Ar′ is bonded is the 9th position) is replaced with deuterium. That is, the compound represented by formula (3-H2-Aa) is preferably a compound represented by the following formula (3-H2-Ab). In formula (3-H2-Ab), D is deuterium, and Ar c ', Ar 14 ', and Ar 15 ' is the same as defined in formula (3-H2-Aa). D in formula (3-H2-Ab) indicates that at least this position is deuterium, and any one or more other hydrogens in formula (3-H2-Ab) may also be deuterium, and it is also preferred that all hydrogens in formula (3-H2-Ab) are deuterium.

[0299] [ka]

[0300] Specific examples of anthracene compounds include compounds represented by formulae (3-131-Y) to (3-182-Y), (3-183-N), (3-184-Y) to (3-284-Y), (3-500) to (3-557), (3-600) to (3-605), and (3-606-Y) to (3-626-Y). The hydrogen atoms in these formulae may be partially or completely substituted with deuterium, and particularly preferred forms of deuterium substitution are listed individually. Y in the formulae is -O-, -S-, >NR 29 (R 29 is defined as above) or >C(-R 30 )2(R 30 may be either an optionally linked aryl or alkyl, and R 29 is, for example, phenyl, R 30 For example, when Y is O, the formula (3-131-Y) becomes the formula (3-131-O), and when Y is -S- or >NR 29 In the case of (3-131-S) or (3-131-N), respectively.

[0301]

change

[0302]

change

[0303]

change

[0304]

change

[0305]

change

[0306]

change

[0307]

change

[0308]

change

[0309]

change

[0310]

change

[0311]

change

[0312] [ka]

[0313] [ka]

[0314] [ka]

[0315] [ka]

[0316] [ka]

[0317] [ka]

[0318] [ka]

[0319] [ka]

[0320] [ka] In the above formula, D is deuterium.

[0321] Among these compounds, the following are also found: (3-131-Y) to (3-134-Y), (3-138-Y), (3-140-Y) to (3-143-Y), (3-150-Y), (3-153-Y) to (3-156-Y), (3-166-Y), (3-168-Y), (3-173-Y), (3-177-Y), (3-180-Y) to (3-183-N), (3-185-Y), (3-190-Y), (3-223-Y), (3-241- Y), formula (3-250-Y), formula (3-252-Y) to formula (3-254-Y), formula (3-270-Y) to formula (3-284-Y), formula (3-501), formula (3-507), formula (3-508), formula (3-509), formula (3-513), formula (3-514), formula (3-519), formula (3-521), formula (3-538) to formula (3-547), or formula (3-600) to formula (3-605), and formula (3-606-Y) to formula (3-626-Y) are preferred. In addition, Y is -O- or >NR 29 is preferred, and -O- is more preferred. Deuterium-substituted forms are also preferred.

[0322] The above anthracene compound is a compound having a reactive group at a desired position of the anthracene skeleton, and an anthracene compound represented by formula (3-H) is a compound having X, Ar 4 The compound can be produced by applying Suzuki coupling, Negishi coupling, or other known coupling reactions using a compound having a reactive group in a partial structure such as the structure of formula (A) as a starting material. Examples of reactive groups in these reactive compounds include halogens and boronic acids. For specific production methods, reference can be made to the synthesis methods described in paragraphs

[0089] to

[0175] of International Publication No. 2014 / 141725.

[0323] [Fluorene compounds] The compound represented by formula (4-H) basically functions as a host. [ka]

[0324] In formula (4-H), R 1 From R 10 are each independently hydrogen, aryl, heteroaryl (the heteroaryl may be bonded to the fluorene skeleton in formula (4-H) via a single bond or a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, in which at least one hydrogen may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl; and R 1 and R 2 , R 2 and R 3 , R 3 and R 4 , R 5 and R 6 , R 6 and R 7 , R 7 and R 8 or R 9 and R 10 may each independently bond to form a fused ring or a spiro ring, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl (the heteroaryl may be bonded to the formed ring via a single bond or a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl. At least one hydrogen atom in the compound represented by formula (4-H) may be substituted with a halogen atom, cyano, or deuterium.

[0325] For details of each group in the definition of formula (4-H), the explanation for formula (1) above can be cited.

[0326] R 1 From R 10Examples of the alkenyl in the formula include alkenyl having 2 to 30 carbon atoms, preferably alkenyl having 2 to 20 carbon atoms, more preferably alkenyl having 2 to 10 carbon atoms, still more preferably alkenyl having 2 to 6 carbon atoms, and particularly preferably alkenyl having 2 to 4 carbon atoms. Preferred alkenyls include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl.

[0327] Specific examples of heteroaryl include monovalent groups represented by removing any one hydrogen atom from a compound of the following formula (4-Ar1), formula (4-Ar2), formula (4-Ar3), formula (4-Ar4), or formula (4-Ar5).

[0328] [ka]

[0329] In formulas (4-Ar1) to (4-Ar5), Y 1 are each independently O, S, or NR, R is phenyl, biphenylyl, naphthyl, anthracenyl, or hydrogen, and at least one hydrogen in the structures of formulae (4-Ar1) to (4-Ar5) may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, phenanthryl, methyl, ethyl, propyl, or butyl.

[0330] These heteroaryls may be bonded to the fluorene skeleton in formula (4-H) via a single bond or a linking group. That is, the fluorene skeleton and the heteroaryl in formula (4-H) may be bonded directly or via a single bond or a linking group. Examples of the linking group include phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, -OCH2CH2-, -CH2CHO-, or -OCH2CHO-.

[0331] Furthermore, R in formula (4-H) 1 and R 2 , R 2 and R 3 , R 3 and R 4 , R 5 and R 6 , R 6 and R 7 or R 7 and R 8 are each independently bonded to form a fused ring, R 9 and R 10 may be bonded to form a spiro ring. 1 From R 8 The fused ring formed by is a ring fused to the benzene ring in formula (4-H), and is an aliphatic ring or an aromatic ring. An aromatic ring is preferable, and examples of the structure containing the benzene ring in formula (4-H) include a naphthalene ring and a phenanthrene ring. 9 and R 10 The spiro ring formed by the formula (4-H) is a ring spiro-bonded to the five-membered ring in formula (4-H), and is an aliphatic ring or an aromatic ring. An aromatic ring, such as a fluorene ring, is preferred.

[0332] The compound represented by formula (4-H) is preferably a compound represented by the following formula (4-H-1), formula (4-H-2), or formula (4-H-3), and in formula (4-H), R 1 and R 2 In formula (4-H), R 3 and R 4 In formula (4-H), R 1 From R 8 is a compound in which none of the above is bound.

[0333] [ka]

[0334] R in formula (4-H-1), formula (4-H-2) and formula (4-H-3) 1From R 10 The definition of R in formula (4-H) corresponds to 1 From R 10 and R in formula (4-H-1) and formula (4-H-2) 11 From R 14 The definition of R in formula (4-H) 1 From R 10 is the same as

[0335] The compound represented by formula (4-H) is more preferably a compound represented by the following formula (4-H-1A), formula (4-H-2A), or formula (4-H-3A), where R 9 and R 10 is a compound in which a spiro-fluorene ring is formed by bonding.

[0336] [ka]

[0337] R in formula (4-H-1A), formula (4-H-2A) and formula (4-H-3A) 2 From R 7 The definition of is the corresponding R in formula (4-H-1), formula (4-H-2) and formula (4-H-3). 2 From R 7 and R in formula (4-H-1A) and formula (4-H-2A) 11 From R 14 The definition of R in formula (4-H-1) and formula (4-H-2) 11 From R 14 is the same as

[0338] In addition, all or part of the hydrogen atoms in the compound represented by formula (4-H) may be substituted with halogen, cyano, or deuterium.

[0339] More specific examples of the fluorene compound as a host include compounds represented by the following structural formulas: [ka]

[0340] [Dibenzochrysene compounds] The dibenzochrysene compound as the host is, for example, a compound represented by the following formula (5-H). [ka]

[0341] In formula (5-H), R 1 From R 16 are each independently hydrogen, aryl, heteroaryl (the heteroaryl may be bonded to the dibenzochrysene skeleton in formula (5-H) via a single bond or a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, in which at least one hydrogen may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl; and R 1 From R 16 Adjacent groups among these may be bonded to each other to form a fused ring, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl (the heteroaryl may be bonded to the formed ring via a single bond or a linking group), diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkenyl, alkoxy, or aryloxy, and at least one hydrogen atom in these may be substituted with an aryl, heteroaryl, alkyl, or cycloalkyl. At least one hydrogen atom in the compound represented by formula (5-H) may be substituted with a halogen atom, cyano, or deuterium.

[0342] For details of each group in the definition of formula (5-H), the explanation for formula (1) above can be cited.

[0343] Examples of alkenyl in the definition of formula (5-H) include alkenyl having 2 to 30 carbon atoms, preferably alkenyl having 2 to 20 carbon atoms, more preferably alkenyl having 2 to 10 carbon atoms, still more preferably alkenyl having 2 to 6 carbon atoms, and particularly preferably alkenyl having 2 to 4 carbon atoms. Preferred alkenyls include vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl.

[0344] Specific examples of heteroaryl include monovalent groups represented by removing any one hydrogen atom from a compound of the following formula (5-Ar1), formula (5-Ar2), formula (5-Ar3), formula (5-Ar4), or formula (5-Ar5).

[0345] [ka]

[0346] In formula (5-Ar1) to formula (5-Ar5), Y 1 are each independently O, S, or NR, R is phenyl, biphenylyl, naphthyl, anthracenyl, or hydrogen, and at least one hydrogen in the structures of formulae (5-Ar1) to (5-Ar5) may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, phenanthryl, methyl, ethyl, propyl, or butyl.

[0347] These heteroaryls may be bonded to the dibenzochrysene skeleton in formula (5-H) via a single bond or a linking group. That is, the dibenzochrysene skeleton and the heteroaryl in formula (5-H) may be bonded directly or via a single bond or a linking group. Examples of the linking group include phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, -OCH2CH2-, -CH2CHO-, and -OCH2CHO-.

[0348] The compound represented by formula (5-H) is preferably R 1 , R 4 , R 5 , R 8 , R 9 , R 12 , R 13 and R 16 is hydrogen. In this case, R in formula (5-H) 2 , R 3 , R 6 , R 7 , R 10 , R 11 , R 14 and R 15 are preferably each independently hydrogen, phenyl, biphenylyl, naphthyl, anthracenyl, phenanthryl, a monovalent group having a structure of formula (5-Ar1), formula (5-Ar2), formula (5-Ar3), formula (5-Ar4), or formula (5-Ar5) (the monovalent group having such a structure may be bonded to the dibenzochrysene skeleton in formula (5-H) via phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, -OCHCH-, -CHCHO-, or -OCHCHO-), methyl, ethyl, propyl, or butyl.

[0349] The compound represented by formula (5-H) is more preferably R 1 , R 2 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , R 12 , R 13 , R 15 and R 16 is hydrogen. In this case, R in formula (5-H) 3 , R 6 , R 11 and R 14at least one (preferably one or two, more preferably one) of the above is a single bond, phenylene, biphenylene, naphthylene, anthracenylene, methylene, ethylene, -OCH2CH2-, -CH2CHO-, or a monovalent group having a structure of formula (5-Ar1), (5-Ar2), (5-Ar3), (5-Ar4), or (5-Ar5) via -OCH2CHO-, and the others (i.e., other than the position where the monovalent group having the above structure is substituted) are hydrogen, phenyl, biphenylyl, naphthyl, anthracenyl, methyl, ethyl, propyl, or butyl, and at least one hydrogen in these may be substituted with phenyl, biphenylyl, naphthyl, anthracenyl, methyl, ethyl, propyl, or butyl.

[0350] Furthermore, R in formula (5-H) 2 , R 3 , R 6 , R 7 , R 10 , R 11 , R 14 and R 15 When a monovalent group having a structure represented by formula (5-Ar1) to formula (5-Ar5) is selected as the group, at least one hydrogen atom in the structure is selected from the group represented by R 1 From R 16 may be bonded to any one of the following to form a single bond.

[0351] More specific examples of the dibenzochrysene compound as a host include compounds represented by the following structural formulas. [ka]

[0352] [ka]

[0353] [Compounds represented by any one of formulas (H1), (H2) and (H3)] As the host material, for example, a compound represented by any one of the following formulas (H1), (H2) and (H3) can be used. [ka]

[0354] In formulas (H1), (H2) and (H3), L 1 is a single bond or a divalent group containing at least an arylene or heteroarylene. 1 L may be a single bond, or a divalent group formed by linking any two of these groups together via -O-, -S-, -CH2-, -Si(-Arx)2- (Arx is aryl), or cycloalkylene. 1 The arylene in the formula (I) is preferably an arylene having 6 to 16 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms, and particularly preferably an arylene having 6 to 10 carbon atoms. Specific examples of the arylene include divalent groups such as a benzene ring, a biphenyl ring, a terphenyl ring, and a fluorene ring. 1The heteroarylene therein is preferably a heteroarylene having 2 to 24 carbon atoms, more preferably a heteroarylene having 2 to 20 carbon atoms, still more preferably a heteroarylene having 2 to 15 carbon atoms, and particularly preferably a heteroarylene having 2 to 10 carbon atoms, and specific examples thereof include a pyrrole ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, an imidazole ring, an oxadiazole ring (such as a furazan ring), a thiadiazole ring, a triazole ring, a tetrazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, an indole ring, and an isoindole ring. , 1H-indazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, 1H-benzotriazole ring, quinoline ring, isoquinoline ring, cinnoline ring, quinazoline ring, quinoxaline ring, phthalazine ring, naphthyridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenoxathiin ring, phenoxazine ring, phenothiazine ring, phenazine ring, indolizine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, and thianthrene ring. At least one hydrogen atom in the compound represented by each of the above formulas may be substituted with at least one group selected from the substituent group Z or deuterium, for example, alkyl having 1 to 6 carbon atoms, cyano, halogen, or deuterium.

[0355] Preferred specific examples include compounds represented by any of the structural formulas listed below. In the structural formulas listed below, at least one hydrogen may be substituted with halogen, cyano, alkyl having 1 to 4 carbon atoms (e.g., methyl or t-butyl), phenyl, naphthyl, or the like.

[0356] [ka]

[0357] [ka]

[0358] [ka]

[0359] [ka]

[0360] [Hole-transporting host material (HH) and electron-transporting host material (EH)] The hole-transporting host material (HH) and the electron-transporting host material (EH) satisfy the following relationship with respect to the HOMO (Highest Occupied Molecular Orbital) and the LUMO (Lowest Unoccupied Molecular Orbital). The HOMO of the hole-transporting host material (HH) is shallower than the HOMO of the electron-transporting host material (EH), and the LUMO of the electron-transporting host material (EH) is deeper than the LUMO of the hole-transporting host material (HH). It is also preferred that the HOMO of the emitting dopant is shallower than the HOMO of the hole-transporting host material (HH), or that the LUMO of the emitting dopant is deeper than the LUMO of the electron-transporting host material (EH).

[0361] In addition, the lowest excited triplet energy level (E T1 ) is the highest E in the emitting layer from the viewpoint of promoting TADF generation without inhibiting it in the emitting layer. T1 E of an emitting dopant or an assisting dopant having T1 It is preferable that the E T1 is the E of the emitting dopant or assisting dopant mentioned above. T1 It is preferable that the E of the host material is higher by 0.01 eV or more, more preferably by 0.03 eV or more, and further preferably by 0.1 eV or more. T1is preferably 2.47 eV or more, more preferably 2.49 eV or more, and even more preferably 2.56 eV or more.

[0362] It is also preferable to use a hole-transporting host material in the hole-transporting layer adjacent to the light-emitting layer and an electron-transporting host material in the electron-transporting layer adjacent to this light-emitting layer. This is because carrier leakage and energy leakage from the light-emitting layer to the adjacent layer are less likely to occur, resulting in a highly efficient organic EL device. The host material (hole-transporting host material) in the light-emitting layer and the material of the hole-transporting layer may be the same or different. Furthermore, the host material (electron-transporting host material) in the light-emitting layer and the material of the electron-transporting layer may be the same or different.

[0363] A preferred example of the hole-transporting host material (HH) is a compound represented by formula (HH-1) or having a partial structure represented by formula (HH-1) and a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings. This compound preferably does not contain any of an imine structure (-N=C-; including a partial structure of a heteroaryl ring), boron (>B-), and cyano (CN).

[0364] [ka]

[0365] In formula (HH-1), Q is >O, >S, or >NA H and In the formula (HH-1), one carbon atom adjacent to the carbon atom to which Q is bonded in each of the two phenyl groups may be bonded to each other via L, L is a single bond, >O, >S, or >C(-A H )2, A H is hydrogen, aryl, or heteroaryl, and >C(-A H )2 in two A H may be bonded to each other.

[0366] When the hole-transporting host material contains a structure represented by formula (HH-1) as a partial structure, it may contain one such partial structure, but it is also preferable to contain two or more such partial structures. When two or more such partial structures are contained, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded so that any rings contained in the partial structures are shared, or may be bonded so that any rings contained in the partial structures are fused to each other. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

[0367] The compound represented by the above formula (HH-1) or having a partial structure represented by formula (HH-1) has a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings. The number of rings contained is preferably 6 or more, more preferably 8 or more. The number is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. The number of rings refers to the number of single rings, and for fused rings, the number is the number of single rings constituting the fused rings.

[0368] The hole-transporting host material is preferably a compound containing one or more partial structures selected from the group consisting of a triarylamine structure, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a fused polycyclic ring containing phenoxazine or phenothiazine. The hole-transporting host material may contain one such partial structure, but preferably contains two or more. When two or more partial structures are contained, the two or more partial structures may be the same or different from each other.

[0369] Specific examples of the hole-transporting host material include the following compounds. [ka]

[0370] [ka]

[0371]

change

[0372]

change

[0373]

change

[0374]

change

[0375]

change

[0376]

change

[0377]

change

[0378]

change

[0379]

change

[0380]

change

[0381] [ka]

[0382] Of the above, HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, HH-1-106 to HH-1-108, and HH-1-109 to HH-1-115 are preferred.

[0383] Examples of the electron-transporting host material (EH) include compounds represented by formulae (EH-1A) to (EH-1D) or compounds having a partial structure represented by formulae (EH-1A) to (EH-1D) and a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings.

[0384] [ka]

[0385] In formulas (EH-1A) to (EH-1D), Ar is a heteroaryl ring containing N=C as a ring-constituting moiety, Z is a single bond, -O-, -S-, or -N(-A E )- and The carbon atom next to the carbon atom to which Z is bonded and the A to which Z is bonded E and may be bonded to each other via L, L is a single bond, >O, >S or >C(-A E )2, A E is aryl, heteroaryl, or triarylsilyl, and >C(-A E )2 in two A E may be bonded to each other, X is C, P or S; When X is C, n=2 and m=1, When X is P, n=3 and m=1, When X is S, n=2 and m=1~2.

[0386] Compounds represented by the above formulae (EH-1A) to (EH-1D) or having a partial structure represented by formulae (EH-1A) to (EH-1D) have a structure containing at least three rings selected from the group consisting of aryl rings and heteroaryl rings. The number of rings contained is preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more. The number is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less. The number of rings refers to the number of monocyclic rings, and for fused rings, the number is the number of monocyclic rings that constitute the fused rings.

[0387] When the electron-transporting host material contains a structure represented by formula (EH-1A) to (EH-1D) as a partial structure, it may contain one of these partial structures, but it is also preferable to contain two or more of these partial structures. When two or more partial structures are contained, the two or more partial structures may be the same or different. The two or more partial structures may be bonded to each other by a single bond, may be bonded so that any rings contained in the partial structures are shared, or may be bonded so that any rings contained in the partial structures are fused to each other. The partial structures may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

[0388] Specific examples of the electron transporting host material include the following compounds. [ka]

[0389] [ka]

[0390] [ka]

[0391] [ka]

[0392] [ka]

[0393] [ka]

[0394] [ka]

[0395] [ka]

[0396] [ka]

[0397] Another preferred example of the electron-transporting host material (a compound having a partial structure represented by formula (EH-1)) is a polycyclic aromatic compound represented by the following formula (EH-1b), or a multimer of a polycyclic aromatic compound having a plurality of structures represented by the following formula (EH-1b). [ka]

[0398] In formula (EH-1b), R 1 , R 2 , R 3 , R 4 and R 5 (Hereinafter referred to as “R 1Each of the groups (also referred to as "groups of groups") independently represents hydrogen or a substituent. The substituent may be a substituent selected from the group Z of substituents. In formula (EH-1b), X 1 and X 2 are each independently >NR (amine nitrogen), >O, >C(-R)2, >S or >Se, and X 1 and X 2 are never both >C(-R)2, R in the >NR and >C(-R)2 each independently represents hydrogen or a substituent selected from the substituent group Z, and may be further substituted with an aryl, heteroaryl, alkyl, or cycloalkyl (all of which are second substituents), and R in the >NR and >C(-R)2 each independently may be bonded to at least one of the ring a, ring b, and ring c via a linking group or a single bond. Y 1 , Y 2 , Y 3 , Y 4 , Y 5 and Y 6 (hereinafter, "Y 1 each independently represents ═C(—R)— or ═N— (pyridinic nitrogen), and at least one represents ═N— (pyridinic nitrogen); Each R in the =C(-R)- is independently hydrogen or a substituent selected from the substituent group Z. R 1 , R 2 , R 3 , R 4 and R 5 , and the Y 1 ~Y 6Adjacent groups among R in =C(-R)- as above may be bonded to each other to form an aryl ring or a heteroaryl ring together with at least one of ring a, ring b, and ring c, and at least one hydrogen atom in the formed ring may be substituted with an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (two aryls may be bonded via a single bond or a linking group), alkyl, cycloalkyl, alkoxy, or aryloxy (all of these, first substituents), and at least one hydrogen atom in these may be further substituted with an aryl, heteroaryl, alkyl, or cycloalkyl (all of these, second substituents). At least one hydrogen atom in the compound and structure represented by formula (EH-1b) may be substituted with cyano, halogen, or deuterium.

[0399] In formula (EH-1b), R 1 , R 2 , R 3 , R 4 and R 5 are all hydrogen atoms, or R 3 and R 4 are both hydrogen and R 1 , R 2 and R 5Preferably, one or more selected from the group consisting of are substituents other than hydrogen, and the rest are hydrogen. The substituents are preferably alkyl, aryl which may be substituted with alkyl or heteroaryl, heteroaryl which may be substituted with alkyl or aryl, or diarylamino which may be substituted with alkyl or aryl. In this case, the alkyl is preferably an alkyl having 1 to 6 carbon atoms (e.g., methyl, t-butyl), the aryl is preferably phenyl or biphenyl, and the heteroaryl is preferably triazinyl, carbazolyl (e.g., 2-carbazolyl, 3-carbazolyl, 9-carbazolyl), pyrimidinyl, pyridinyl, dibenzofuranyl, or dibenzothienyl. Specific examples include phenyl, biphenyl, diphenyltriazinyl, carbazolyltriazinyl, monophenylpyrimidinyl, diphenylpyrimidinyl, carbazolyltriazinyl, pyridinyl, dibenzofuranyl, and dibenzothienyl.

[0400] Y 1 etc. are each independently =C(-R)- or =N-, and at least one is =N-. Y 1 ~Y 6 Any of the groups may be =N-. Preferably, Y 1 and Y 6 =N-(a ring is a pyrimidine ring), Y 1 or Y 6 =N-(a ring is a pyridine ring), Y 2 and Y 5 =N-(ring b and ring c are pyridine rings), Y 3 and Y 4 =N-(ring b and ring c are pyridine rings), Y 2 ~Y 5 is =N-(ring b and ring c are pyrimidine rings), Y 1 , Y 3 , Y 4 and Y 6 is =N-(a ring is a pyrimidine ring, b ring and c ring are pyridine rings), Y 1 , Y 2 , Y 5 and Y 6is =N-(a ring is a pyrimidine ring, b ring and c ring are pyridine rings), Y 1 ~Y 6 is =N-(a ring, b ring and c ring are pyrimidine rings), Y 2 or Y 5 is =N-(ring b or ring c is a pyridine ring).

[0401] In addition to the above =N- arrangement, X 1 and X 2 is preferably >O, and a polycyclic aromatic compound containing a partial structure represented by any of the following formulas is preferred. [ka]

[0402] In particular, polycyclic aromatic compounds containing a partial structure represented by formula (EH-1b-N1) have a higher E S1 , high E T1 , small ΔE S1T1 It has. Specific examples of the polycyclic aromatic compound represented by formula (EH-1b) are shown below.

[0403] [ka]

[0404] [ka]

[0405] [ka]

[0406] [ka]

[0407] [ka]

[0408] [ka]

[0409] Of the above, EH-1-1 to EH-1-4, EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 to EH-1-59, EH-1-61, EH-1-66, EH-1-68, EH-1-71, EH-1-72, EH-1-90, EH-1-94 to EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1-115, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130 are preferred.

[0410] [Combination of hole-transporting host material and electron-transporting host material] The combination of the hole-transporting host material and the electron-transporting host material is such that the HOMO, LUMO, and lowest excited triplet energy levels (E T1 ) is selected. With regard to the HOMO and LUMO, a combination is selected in which the HOMO(HH) of the hole-transporting host material is shallower than the HOMO(EH) of the electron-transporting host material and the LUMO(EH) of the electron-transporting host material is deeper than the LUMO(HH) of the hole-transporting host material. More specifically, a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.10 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.10 eV or more is preferred, a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.20 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.20 eV or more is more preferred, and a combination in which the HOMO(HH) is shallower than the HOMO(EH) by 0.25 eV or more and the LUMO(HH) is deeper than the HOMO(EH) by 0.25 eV or more is even more preferred.

[0411] The hole-transporting host material and the electron-transporting host material may be combined to form an association called an exciplex. It is generally known that exciplexes are easily formed between a material with a relatively deep LUMO level and a material with a shallow HOMO level. The interaction between the hole-transporting host material and the electron-transporting host material, specifically, whether an exciplex is formed, can be determined by forming a single-layer film consisting of only the hole-transporting host material and the electron-transporting host material under the same conditions as for forming the light-emitting layer, measuring the emission spectrum (fluorescence or phosphorescence spectrum), and comparing the obtained emission spectrum with the emission spectrum of each of the hole-transporting host material and the electron-transporting host material alone. This can be determined by the spectrum of a mixed film containing the hole-transporting host material and the electron-transporting host material exhibiting an emission wavelength different from both the spectrum of the film of the hole-transporting host material and the spectrum of the film of the electron-transporting host material. Specifically, a difference of 10 nm or more in the peak wavelength of the spectrum can be used as an indicator.

[0412] Specific examples of the combination of a hole-transporting host material and an electron-transporting host material that do not form an exciplex include the following combinations: T1 In order to satisfy the physical property values ​​of (1), the hole-transporting host material is preferably a compound having carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, more preferably a compound having carbazole, dibenzofuran, or dibenzothiophene as a partial structure, and even more preferably a compound having carbazole as a partial structure. Similarly, the electron-transporting host material is preferably a compound having pyridine, triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, and even more preferably a compound having triazine.

[0413] More specifically, the hole-transporting host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, and HH-1-106 to HH-1-108, and the electron-transporting host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-5, EH-1-6, EH-1-7, EH-1-8, EH-1-9, EH-1-10, EH-1-11, EH-1-12, EH-1-13, EH-1-14, EH-1-15, EH-1-16, EH-1-17, EH-1-18, HH-1-20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, and HH-1-106 to HH-1-108. It is preferable that the polyisoprene is selected from the group consisting of EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 to EH-1-59, EH-1-61, EH-1-71, EH-1-72, EH-1-90, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130. Preferred examples of combinations include Compound HH-1-1 and Compound EH-1-22, Compound HH-1-1 and Compound EH-1-23, Compound HH-1-1 and Compound EH-1-24, Compound HH-1-2 and Compound EH-1-22, Compound HH-1-2 and Compound EH-1-23, Compound HH-1-2 and Compound EH-1-24, or Compound HH-1-1 and Compound EH-1-128.

[0414] Specific examples of the combination of a hole-transporting host material and an electron-transporting host material that form an exciplex include the following combinations: T1In order to satisfy the physical property values ​​of (1), the hole-transporting host material is preferably a compound having carbazole, triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, more preferably a compound having triarylamine, indolocarbazole, or benzoxazinophenoxazine as a partial structure, and even more preferably a compound having triarylamine as a partial structure. Similarly, the electron-transporting host material is preferably a compound having pyridine, triazine, phosphine oxide, or benzofuropyridine as a partial structure, more preferably a compound having triazine, phosphine oxide, benzofuropyridine, or dibenzoxasiline as a partial structure, and even more preferably a compound having phosphine oxide or triazine.

[0415] More specifically, the hole-transporting host material is preferably selected from the group consisting of HH-1-1, HH-1-2, HH-1-11, HH-1-12, HH-1-17, HH-1-18, HH-1-23, HH-1-24, and HH-1-115, and the electron-transporting host material is preferably selected from the group consisting of EH-1-1 to EH-1-4, EH-1-21 to EH-1-25, and EH-1-5. It is preferable that the copolymer is selected from the group consisting of EH-1-1 to EH-1-57, EH-1-59, EH-1-66, EH-1-68, EH-1-90, EH-1-94, EH-1-99, EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130. Preferred examples of combinations include Compound HH-1-1 and Compound EH-1-21, Compound HH-1-2 and Compound EH-1-21, Compound HH-1-12 and Compound EH-1-94, Compound HH-1-12 and Compound EH-1-117, Compound HH-1-1 and Compound EH-1-130, Compound HH-1-33 and Compound EH-1-117, Compound HH-1-48 and Compound EH-1-117, Compound HH-1-49 and Compound EH-1-117, or Compound HH-1-115 and Compound EH-1-99.

[0416] Other specific combinations of hole-transporting host materials and electron-transporting host materials are described in Organic Electronics 66 (2019) 227-24, Advanced Functional Materials 25 (2015) 361-366, Advanced Materials 26 (2014) 4730-4734, ACS Applied Materials and Interfaces 8 (2016) 32984-32991, ACS Applied Materials and Interfaces 2016, 8, 9806-9810, ACS Applied Materials and Interfaces 2016, 8, 32984-32991, Journal of Materials Chemistry C, 2018, 6, 8784-8792, Angewante Chemie International Edition, 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684, Synthetic Metals, 201, 2015, 49, and Nature Photonics, 16, 212-218 (2022) can be referenced.

[0417] <Assisting dopant (thermally activated delayed fluorescent material or phosphorescent material)> The light-emitting layer preferably contains an assisting dopant in addition to the emitting dopant and the host material. The assisting dopant is preferably a thermally activated delayed fluorescent material or a phosphorescent material. As described above, the polycyclic aromatic compound represented by formula (1) has reduced interaction with adjacent molecules and can be preferably used as an emitting dopant in a TAF element or a PSF element.

[0418] In this embodiment, known host compounds can be used, such as compounds having at least one of a carbazole ring and a furan ring. Among these, compounds having at least one of a furanyl group and a carbazolyl group bonded to at least one of an arylene group and a heteroarylene group are preferred. Specific examples include compounds represented by formulas (H1), (H2), and (H3), particularly mCP and mCBP, as well as compounds HH-1-115 and EH-1-99. A TADF-active compound may also be used as the host compound. In this embodiment, it is also preferred to use a combination of a hole-transporting host material and an electron-transporting host material as the host.

[0419] The lowest excited triplet energy level E(1,T,Sh), which is determined from the shoulder on the short-wavelength side of the peak of the phosphorescence spectrum of the host compound, is preferably higher than the lowest excited triplet energy levels E(2,T,Sh) and E(3,T,Sh) of the emitting dopant or assisting dopant having the highest lowest excited triplet energy level in the emitting layer, from the viewpoint of promoting rather than inhibiting the generation of TADF in the emitting layer. Specifically, the lowest excited triplet energy level E(1,T,Sh) of the host compound is preferably higher than E(2,T,Sh) and E(3,T,Sh) by 0.01 eV or more, more preferably by 0.03 eV or more, and even more preferably by 0.1 eV or more.

[0420] [Thermal activated delayed fluorescent substance] "Thermally activated delayed fluorescent material" refers to a compound that absorbs thermal energy, undergoes reverse intersystem crossing from the lowest excited triplet state to the lowest excited singlet state, and then radiatively deactivates from the lowest excited singlet state to emit delayed fluorescence. However, "thermally activated delayed fluorescent material" also includes compounds that undergo higher triplets during the excitation process from the lowest excited triplet state to the lowest excited singlet state. For example, see the paper by Monkman et al. of Durham University (NATURE COMMUNICATIONS, 7:13680, DOI: 10.1038 / ncomms13680), the paper by Hosokai et al. of the National Institute of Advanced Industrial Science and Technology (Hosokai et al., Sci. Adv. 2017;3: e1603282), the paper by Sato et al. of Kyoto University (Scientific Reports, 7:4820, DOI: 10.1038 / s41598-017-05007-7), and the paper by Sato et al. of Kyoto University (Scientific Reports, 7:4820, DOI: 10.1038 / s41598-017-05007-7). (The 98th Annual Meeting of the Chemical Society of Japan, Presentation Number: 2I4-15, "Mechanism of Highly Efficient Emission in Organic Electroluminescence Using DABNA as an Emitting Molecule," Graduate School of Engineering, Kyoto University), a review by Bui et al. (DOI: 10.3762 / bjoc.14.18), a review by Duan et al. (DOI: 10.1063 / 1.5143501), a review by Ding et al. (DOI: 10.1088 / 1674-4926 / 42 / 5 / 050201), and a review by Xie et al. (DOI: 10.1002 / adom.202002204). In the present invention, when a sample containing the target compound is measured for its fluorescence lifetime at 300 K, if a slow fluorescent component is observed, the target compound is determined to be a "thermally activated delayed fluorescent substance." Here, the term "slow fluorescent component" refers to a component whose fluorescent lifetime is 0.1 μsec or longer. The fluorescent lifetime can be measured using, for example, a fluorescent lifetime measuring device (manufactured by Hamamatsu Photonics KK, C11367-01).

[0421] In an emitting layer further containing a "thermally activated delayed phosphor" as an assisting dopant, the polycyclic aromatic compound of the present invention can function as an emitting dopant. That is, the "thermally activated delayed phosphor" can function as an assisting dopant that assists the emission of the polycyclic aromatic compound of the present invention. In this specification, an organic electroluminescent device that uses a thermally activated delayed fluorescent substance as an assisting dopant may be referred to as a "TAF device" (TADF Assisting Fluorescence device). The "host compound" in a TAF element means a compound whose lowest excited singlet energy level, determined from the shoulder on the short-wavelength side of the peak of the fluorescence spectrum, is higher than that of the thermally activated delayed fluorescent substance as an assisting dopant and the emitting dopant.

[0422] The thermally activated delayed phosphor (TADF compound) used in the TAF element is preferably a donor-acceptor type thermally activated delayed phosphor (DA type TADF compound) designed to localize the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) within the molecule using an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor, thereby causing efficient reverse intersystem crossing.

[0423] In this specification, the term "electron-donating substituent" (donor) refers to a substituent and a partial structure in which the HOMO is localized in the thermally activated delayed fluorescent substance molecule, and the term "electron-accepting substituent" (acceptor) refers to a substituent and a partial structure in which the LUMO is localized in the thermally activated delayed fluorescent substance molecule.

[0424] In general, thermally activated delayed fluorescent materials using donors and acceptors have large spin-orbit coupling (SOC) due to their structure, and small exchange interaction between HOMO and LUMO, resulting in a low ΔE S1T1 Since the λ / 2 is small, a very fast reverse intersystem crossing rate can be obtained. By using the polycyclic aromatic compound of the present invention as an emitting dopant and a thermally activated delayed phosphor (TADF material) as an assisting dopant, a device can be obtained that satisfies any one or all of high efficiency, high color purity, and long life. The thermally activated delayed phosphor may be a compound whose emission spectrum at least partially overlaps with the absorption spectrum of the polycyclic aromatic compound of the present invention. The polycyclic aromatic compound of the present invention and the thermally activated delayed phosphor may both be contained in the same layer, an adjacent layer, or another nearby layer.

[0425] As the thermally activated delayed phosphor in the TAF element, for example, a compound in which a donor and an acceptor are bonded directly or via a spacer can be used.As the electron donating group (donor structure) and electron accepting group (acceptor structure) used in the thermally activated delayed phosphor of the present invention, for example, the structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used. Donor structures include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis(tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridinediamine, tetramethyl-dihydro-indenoacridine, and diphenyl-dihydrodibenzazasiline.Acceptor structures include sulfonyldibenzene, benzophenone, phenylenebis(phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthracenone, anthracenedione, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorene dicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthene dioxide, thianthrene tetraoxide, and tris(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence in the TAF element is preferably a compound having at least one partial structure selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole, and benzophenone.

[0426] The compound used as the assisting dopant in the light-emitting layer of the TAF element is preferably a thermally activated delayed phosphor, the emission spectrum of which at least partially overlaps with the absorption peak of the emitting dopant.

[0427] [Phosphorescent materials (assisting dopants)] In the light-emitting layer, a phosphorescent material may be used as an assisting dopant. In this specification, an organic electroluminescent device using a phosphorescent material as an assisting dopant is sometimes referred to as a phosphorescence-assisted device, phosphor-sensitized fluorescent device, or PSF device. Phosphorescent materials utilize the intramolecular spin-orbit interaction (heavy atom effect) of metal atoms to obtain light emission from an excited triplet state. As such phosphorescent materials, for example, luminescent metal complexes can be used. Examples of luminescent metal complexes include compounds represented by the following formulas (B-1) and (B-2).

[0428] [ka]

[0429] In formula (B-1), M is at least one selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu, n is an integer of 1 to 3, and each "XY" is independently a bidentate ligand. In formula (B-2), M is at least one selected from the group consisting of Pt, Re, and Cu, and "WXYZ" is a tetradentate ligand. In the formula (B-1), M is preferably Ir and n is preferably 3 from the viewpoints of efficiency and life. In the formula (B-2), M is preferably Pt from the viewpoint of efficiency and life. The ligand (XY) in formula (B-1) has at least one ligand selected from the group consisting of: The ligand (WXYZ) in formula (B-2) has at least one ligand selected from the group consisting of:

[0430] [ka]

[0431] During the ceremony, --- binds to the central metal M, Y is independently BR e , N.R. e , PR e , O, S, Se, C=O, S=O, SO2, CR e R f , SiR e R f , or GeR e R f and Each aromatic carbon atom CH in the ring may be independently substituted with N; R e and R f may be optionally fused or linked to form a ring, R a , R b , R c , and R d may each independently be unsubstituted or substituted with from 1 to the maximum possible number of substitutions, R a , R b , R c , R d , R e , and R f are each independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, or a combination thereof; However, R a , R b , R c , and R d Any two adjacent substituents in may be fused or linked to form a ring or to form a multidentate ligand.

[0432] Examples of the compound represented by formula (B-1) include Ir(ppy)3, Ir(ppy)2(acac), Ir(mppy)3, Ir(PPy)2(m-bppy), BtpIr(acac), Ir(btp)2(acac), Ir(2-phq)3, Hex-Ir(phq)3, Ir(fbi)2(acac), and fac-Tris(2-(3-p-xylyl)phenyl)pyridine. iridium(III), Eu(dbm)3(Phen), Ir(piq)3, Ir(piq)2(acac), Ir(Fliq)2(acac), Ir(Flq)2(acac), Ru(dtb-bpy)3·2(PF6), Ir(2-phq)3, Ir(BT)2(acac), Ir(DMP)3 , Ir(Mphq)3IR(phq)2tpy, fac-Ir(ppy)2Pc, Ir(dp)PQ2, Ir(Dpm)(Piq)2, Hex-Ir(piq)2(acac), Hex-Ir(piq)3, Ir(dmpq)3, Ir(dmpq)2(acac), FPQIrpic, etc.

[0433] Other examples of the compound represented by formula (B-1) include the following compounds: [ka]

[0434] [ka]

[0435] [ka]

[0436] In addition, iridium complexes described in JP 2006-089398 A, JP 2006-080419 A, JP 2005-298483 A, JP 2005-097263 A, and JP 2004-111379 A, ​​U.S. Patent Application Publication No. 2019 / 0051845, or Advanced Materials, 26: 7116-7121, NPG Asia Materials 13, 53 (2021), Applied Physics Letters, 117, 253301 (2020), Light-Emitting Diode - An Outlook On the Empirical Features and Its Recent Technological Advancements, Chapter 5 Platinum complexes described may also be used.

[0437] <Other dopant materials> The polycyclic aromatic compound represented by formula (1) may be used in combination with other dopant materials. However, the amount of the other dopant materials in one light-emitting layer is preferably less than 100% by mass, more preferably 50% by mass or less, even more preferably 30% by mass or less, and particularly preferably 10% by mass or less, based on the total mass of the polycyclic aromatic compound represented by formula (1). Known compounds can be used as the other dopant materials, and they can be selected from a variety of materials depending on the desired emission color.Specific examples include fused ring derivatives of phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and chrysene, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, and tetraphenylbutadiene. derivatives, cyclopentadiene derivatives, bisstyryl derivatives such as bisstyryl anthracene derivatives and distyrylbenzene derivatives (JP Patent Publication No. 245087 / 1999), bisstyrylarylene derivatives (JP Patent Publication No. 247278 / 1990), diazaindacene derivatives, furan derivatives, benzofuran derivatives, isobenzofuran derivatives such as phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, and phenylisobenzofuran Coumarin derivatives such as dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzimidazolylcoumarin derivatives, and 3-benzoxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzanthracene derivatives, xanthene derivatives, and rhodamine derivatives. conductors, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, violanthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives, and benzofluorene derivatives.

[0438] As other dopant materials, it is also preferable to use polycyclic aromatic compounds containing boron described in WO 2015 / 102118, WO 2020 / 162600, paragraphs 0097 to 0269 of JP 2021-077890, etc.

[0439] 2-1-6. Electron injection layer and electron transport layer in organic electroluminescent devices The electron injection layer 107 plays a role of efficiently injecting electrons moving from the cathode 108 into the light-emitting layer 105 or the electron transport layer 106. The electron transport layer 106 plays a role of efficiently transporting electrons injected from the cathode 108 or electrons injected from the cathode 108 via the electron injection layer 107 to the light-emitting layer 105. The electron transport layer 106 and the electron injection layer 107 are each formed by laminating or mixing one or more electron transport / injection materials, or by a mixture of an electron transport / injection material and a polymer binder.

[0440] The electron injection / transport layer is a layer responsible for injecting electrons from the cathode and transporting them. It is desirable for the layer to have high electron injection efficiency and efficiently transport the injected electrons. To achieve this, it is preferable for the material to have high electron affinity, high electron mobility, excellent stability, and be less likely to generate trapping impurities during manufacture and use. However, considering the balance between hole and electron transport, if a material primarily serves to efficiently block holes from the anode from flowing to the cathode without recombining, it can have the same effect of improving luminous efficiency as a material with high electron transport ability, even if it does not have a particularly high electron transport ability. Therefore, the electron injection / transport layer in this embodiment may also function as a layer that can efficiently block the movement of holes.

[0441] The material (electron transport material) for forming the electron transport layer 106 or the electron injection layer 107 can be arbitrarily selected from compounds conventionally used as electron transport compounds in photoconductive materials and known compounds used in electron injection layers and electron transport layers of organic EL devices.

[0442] Materials used in the electron transport layer or electron injection layer preferably contain at least one selected from the group consisting of aromatic or heteroaromatic ring compounds composed of one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon, and phosphorus; pyrrole derivatives and their fused ring derivatives; and metal complexes containing electron-accepting nitrogen. Specific examples include fused ring aromatic derivatives such as naphthalene and anthracene; styryl aromatic derivatives such as 4,4'-bis(diphenylethenyl)biphenyl; perinone derivatives; coumarin derivatives; naphthalimide derivatives; quinone derivatives such as anthraquinone and diphenoquinone; phosphine oxide derivatives; arylnitrile derivatives; and indole derivatives. Metal complexes containing electron-accepting nitrogen include, for example, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. These materials can be used alone or in combination with other materials.

[0443] Specific examples of other electron transport compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (e.g., 1,3-bis[(4-t-butylphenyl)1,3,4-oxadiazolyl]phenylene), thiophene derivatives, triazole derivatives (e.g., N-naphthyl-2,5-diphenyl-1,3,4-triazole), thiadiazole derivatives, metal complexes of oxine derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, and the like. Examples of the compound include benzoquinolin-2-yl-9,9'-spirobifluorene, benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(2,2':6',2"-terpyridin-4'-yl)benzene, naphthyridine derivatives (bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphine oxide derivatives, and bisstyryl derivatives.

[0444] Furthermore, metal complexes having an electron-accepting nitrogen atom can also be used, and examples thereof include hydroxyazole complexes such as quinolinol metal complexes and hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

[0445] The above-mentioned materials may be used alone or in combination with other materials.

[0446] Among the above-mentioned materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO-based derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metal complexes are preferred.

[0447] The electron transport layer or the electron injection layer may further contain a substance capable of reducing the material forming the electron transport layer or the electron injection layer. Various substances can be used as this reducing substance as long as they have a certain level of reducing ability. For example, at least one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkaline earth metal oxides, alkaline earth metal halides, rare earth metal oxides, rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, and rare earth metal organic complexes can be suitably used.

[0448] Preferred reducing substances include alkali metals such as Na (work function 2.36 eV), K (2.28 eV), Rb (2.16 eV), and Cs (1.95 eV), and alkaline earth metals such as Ca (2.9 eV), Sr (2.0-2.5 eV), and Ba (2.52 eV), with substances with a work function of 2.9 eV or less being particularly preferred. Among these, more preferred reducing substances are alkali metals such as K, Rb, and Cs, with Rb or Cs being even more preferred, and Cs being the most preferred. These alkali metals have particularly high reducing ability, and adding a relatively small amount of these metals to the material forming the electron transport layer or electron injection layer can improve the luminance and extend the life of the organic EL device. Furthermore, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more of these alkali metals is also preferred, and in particular, a combination containing Cs is preferred, such as a combination of Cs and Na, Cs and K, Cs and Rb, or Cs, Na and K. By including Cs, the reducing ability can be efficiently exerted, and by adding Cs to the material forming the electron transport layer or electron injection layer, the luminance of the organic EL device can be improved and the lifetime can be extended.

[0449] 2-1-7. Cathode in organic electroluminescent devices The cathode 108 serves to inject electrons into the light-emitting layer 105 through the electron injection layer 107 and the electron transport layer 106 .

[0450] The material for the cathode 108 is not particularly limited as long as it can efficiently inject electrons into the organic layer, but materials similar to those for the anode 102 can be used. Among these, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium, and magnesium, or alloys thereof (e.g., magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys such as lithium fluoride / aluminum alloys), are preferred. To increase electron injection efficiency and improve device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low-work-function metals are effective. However, these low-work-function metals are generally unstable in air. To address this issue, a method has been proposed in which a trace amount of lithium, cesium, or magnesium is doped into the organic layer to create a highly stable electrode. Other dopants that can be used include inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide, and cesium oxide. However, these are not limited to these.

[0451] Further, for electrode protection, preferred examples include lamination of metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, inorganic materials such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon polymer compounds, etc. The method for producing these electrodes is not particularly limited as long as electrical conduction can be achieved, and may include resistance heating, electron beam evaporation, sputtering, ion plating, and coating.

[0452] 2-1-8. Method for producing organic electroluminescent device Each layer constituting an organic EL device can be formed by forming the material to be formed into a thin film using methods such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, spin coating or casting, and coating. There are no particular limitations on the film thickness of each layer formed in this way, and it can be set appropriately depending on the properties of the material, but it is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a quartz oscillator film thickness measuring device or the like. When forming a thin film using vapor deposition, the vapor deposition conditions vary depending on the type of material, the desired crystal structure and association structure of the film, etc. Vapor deposition conditions are generally a boat heating temperature of +50 to +400°C, a vacuum degree of 10 -6 ~10 -3 It is preferable to appropriately set the pressure, the deposition rate, the substrate temperature, and the film thickness in the range of 0.01 to 50 nm / sec, -150 to +300° C., and 2 nm to 5 μm.

[0453] When applying a DC voltage to the organic EL element obtained in this way, the anode should be set to + and the cathode to -. When a voltage of about 2 to 40 V is applied, light emission can be observed from the transparent or semi-transparent electrode side (anode or cathode, or both). This organic EL element also emits light when a pulse current or an AC current is applied. The waveform of the applied AC current can be any waveform.

[0454] Next, as an example of a method for producing an organic EL element, a method for producing an organic EL element comprising an anode, a hole injection layer, a hole transport layer, an emitting layer composed of a host material and a dopant material, an electron transport layer, an electron injection layer, and a cathode will be described.

[0455] <Vapor deposition method> An anode is prepared by forming a thin film of an anode material on a suitable substrate by vapor deposition or the like, and then forming thin films of a hole injection layer and a hole transport layer on the anode. A host material and a dopant material are co-deposited on the anode to form a thin film to serve as an emissive layer. An electron transport layer and an electron injection layer are then formed on the emissive layer, and a thin film of a cathode material is then formed by vapor deposition or the like to serve as a cathode, thereby obtaining the desired organic EL device. It is also possible to reverse the order of fabrication of the organic EL device described above, by fabricating the layers in the order of cathode, electron injection layer, electron transport layer, emissive layer, hole transport layer, hole injection layer, and anode.

[0456] <Wet film formation method> The wet film formation method is carried out by preparing a liquid organic layer-forming composition from a low molecular weight compound capable of forming each organic layer of an organic EL device, and using this. If there is no suitable organic solvent that can dissolve this low molecular weight compound, the organic layer-forming composition may be prepared from a reactive compound obtained by substituting a reactive substituent on the low molecular weight compound, such as another monomer having a solubility function as a reactive compound, or a polymer compound polymerized together with a main-chain polymer.

[0457] In wet film formation, a coating film is generally formed through a coating step in which an organic layer-forming composition is applied to a substrate and a drying step in which the solvent is removed from the applied organic layer-forming composition. When the polymer compound has a crosslinkable substituent (also called a crosslinkable polymer compound), the drying step further crosslinks the polymer to form a crosslinked polymer. Depending on the coating process, methods using a spin coater are called spin coating methods; methods using a slit coater are called slit coating methods; methods using a printing plate are called gravure, offset, reverse offset, or flexographic printing methods; methods using an inkjet printer are called inkjet methods; and methods spraying the composition in a mist are called spray methods. Drying methods include air drying, heating, and vacuum drying. The drying process may be performed once or multiple times using different methods and conditions. Different methods, such as baking under reduced pressure, may also be used in combination.

[0458] Wet film formation methods are film formation methods that use solutions, such as some printing methods (inkjet methods), spin coating or casting methods, and coating methods. Unlike vacuum deposition methods, wet film formation methods do not require expensive vacuum deposition equipment and can form films under atmospheric pressure. In addition, wet film formation methods allow for large-area and continuous production, which leads to reduced manufacturing costs.

[0459] On the other hand, compared to vacuum deposition, wet deposition can be difficult to layer. When using wet deposition to create layered films, it is necessary to prevent the dissolution of the lower layer by the composition of the upper layer, and methods such as controlled solubility compositions, crosslinking of the lower layer, and orthogonal solvents (solvents that are not soluble in each other) are used. However, even with these techniques, it can be difficult to use wet deposition for all film application.

[0460] Therefore, a common method for fabricating organic EL devices is to use a wet film-forming method for only some layers and a vacuum deposition method for the remaining layers.

[0461] For example, the procedure for producing an organic EL element by partially applying a wet film formation method is shown below. (Step 1) Forming the anode film by vacuum deposition (Step 2) Forming a film by a wet film formation method using a composition for forming a hole injection layer containing a material for the hole injection layer (Step 3) Forming a film by a wet film formation method using a composition for forming a hole transport layer containing a material for the hole transport layer (Step 4) Forming a film by a wet film formation method using a composition for forming an emitting layer containing a host material and a dopant material (Step 5) Formation of the electron transport layer by vacuum deposition (Step 6) Formation of the electron injection layer by vacuum deposition (Step 7) Cathode deposition by vacuum evaporation Through this procedure, an organic EL element consisting of an anode, a hole injection layer, a hole transport layer, a light-emitting layer made of a host material and a dopant material, an electron transport layer, an electron injection layer, and a cathode is obtained. Of course, the electron transport layer and the electron injection layer may also be formed by a wet film formation method using layer-forming compositions containing the electron transport layer material and the electron injection layer material, respectively. In this case, it is preferable to use a method to prevent dissolution of the underlying light-emitting layer or a method to form the layer from the cathode side, in the reverse order of the above procedure.

[0462] <Other film formation methods> The organic layer-forming composition can be formed into a film by laser thermal imaging (LITI), a method in which a compound attached to a substrate is heated and vapor-deposited with a laser, and the organic layer-forming composition can be used as the material applied to the substrate.

[0463] <Optional process> Before and after each film-forming step, appropriate treatment steps, cleaning steps, and drying steps may be added as appropriate. Examples of treatment steps include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent, and heat treatment. Furthermore, a series of steps for preparing a bank may also be included.

[0464] Photolithography can be used to fabricate the banks. Positive and negative resist materials can be used as bank materials for photolithography. Patternable printing methods such as inkjet printing, gravure offset printing, reverse offset printing, and screen printing can also be used. In these cases, permanent resist materials can also be used.

[0465] <Composition for forming organic layer used in wet film formation method> The organic layer-forming composition is obtained by dissolving a low-molecular-weight compound capable of forming each organic layer of an organic EL device, or a polymer compound obtained by polymerizing such a low-molecular-weight compound, in an organic solvent. For example, the light-emitting layer-forming composition contains at least one polycyclic aromatic compound (or a polymer compound thereof) as a dopant material as a first component, at least one host material as a second component, and at least one organic solvent as a third component. The first component functions as a dopant component for the light-emitting layer obtained from the composition, and the second component functions as a host component for the light-emitting layer. The third component functions as a solvent that dissolves the first and second components in the composition, and upon application, the controlled evaporation rate of the third component itself provides a smooth and uniform surface profile.

[0466] <Organic solvents> The organic layer-forming composition contains at least one organic solvent. By controlling the evaporation rate of the organic solvent during film formation, it is possible to control and improve film-forming properties, the presence or absence of defects in the coating film, surface roughness, and smoothness. Furthermore, when forming a film using an inkjet method, it is possible to control meniscus stability at the pinhole of the inkjet head and control and improve ejection properties. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, it is possible to improve the electrical properties, luminescence properties, efficiency, and lifespan of an organic EL device having an organic layer obtained from the organic layer-forming composition.

[0467] After film formation, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, or heating. When heating is performed, from the viewpoint of improving coating film-forming properties, it is preferable to perform the heating at a temperature not higher than 30°C above the glass transition temperature (Tg) of at least one of the solutes. Furthermore, from the viewpoint of reducing residual solvent, it is preferable to perform the heating at a temperature not lower than 30°C below the glass transition temperature (Tg) of at least one of the solutes. Even if the heating temperature is lower than the boiling point of the organic solvent, the organic solvent can be sufficiently removed because the film is thin. Furthermore, drying may be performed multiple times at different temperatures, or multiple drying methods may be used in combination.

[0468] Examples of organic solvents used in the organic layer-forming composition include, but are not limited to, alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, monocyclic ketone solvents, solvents having a diester skeleton, and fluorine-containing solvents. The solvents may be used alone or in combination.

[0469] <Optional ingredients> The composition for forming the organic layer may contain optional components, such as a binder and a surfactant, to the extent that the properties of the composition are not impaired.

[0470] <Composition and Properties of the Organic Layer-Forming Composition> The content of each component in the composition for forming an organic layer is determined taking into consideration the good solubility, storage stability, and film-forming properties of each component in the composition for forming an organic layer, as well as the good film quality of the coating film obtained from the composition for forming an organic layer, good ejection properties when an inkjet method is used, and good electrical properties, light-emitting properties, efficiency, and lifespan of an organic EL element having an organic layer produced using the composition.

[0471] The composition for forming an organic layer can be produced by appropriately selecting the above-mentioned components by a known method, such as stirring, mixing, heating, cooling, dissolving, dispersing, etc. After preparation, the composition may be appropriately subjected to filtration, degassing (also called degassing), ion exchange treatment, inert gas substitution / filling treatment, etc.

[0472] 2-1-9.Application examples of organic electroluminescent devices The present invention can also be applied to a display device having an organic EL element or a lighting device having an organic EL element. A display device or lighting device including an organic EL element can be manufactured by a known method, for example, by connecting the organic EL element according to this embodiment to a known driving device, and can be driven appropriately using a known driving method such as DC driving, pulse driving, or AC driving.

[0473] Examples of display devices include panel displays such as color flat panel displays, and flexible displays such as flexible color organic electroluminescent (EL) displays (see, for example, JP-A-10-335066, JP-A-2003-321546, and JP-A-2004-281086). Examples of display methods include matrix and segment methods. Note that matrix display and segment display may coexist on the same panel.

[0474] In a matrix display, pixels are arranged two-dimensionally, such as in a grid or mosaic pattern, and a collection of pixels displays characters and images. The shape and size of the pixels are determined by the application. For example, images and text displayed on computers, monitors, and televisions typically use square pixels with sides of 300 μm or less. Large displays such as display panels use pixels on the order of millimeters. For monochrome displays, pixels of the same color are simply arranged, while for color displays, red, green, and blue pixels are displayed side by side. These types are typically known as delta and stripe types. The matrix can be driven by either line-sequential or active matrix methods. While line-sequential driving has the advantage of being simpler, active matrix methods can sometimes be superior in terms of operating characteristics, so the choice must be made based on the application.

[0475] In the segment type, a pattern is formed to display predetermined information, and a predetermined area is illuminated. Examples include the time and temperature displays on digital clocks and thermometers, the operating status displays on audio equipment and induction cookers, and panel displays on automobiles.

[0476] Examples of lighting devices include lighting devices for indoor lighting and backlights for liquid crystal display devices (see, for example, JP 2003-257621 A, JP 2003-277741 A, JP 2004-119211 A, etc.). Backlights are primarily used to improve the visibility of non-self-luminous display devices, and are used in liquid crystal display devices, clocks, audio devices, automobile panels, display boards, signs, etc. In particular, for backlights for liquid crystal display devices, particularly for personal computers where thinning is an issue, considering that conventional systems use fluorescent lamps and light guide plates and therefore make thinning difficult, backlights using the light-emitting elements according to this embodiment are characterized by their thinness and light weight.

[0477] 2-2. Other organic devices The polycyclic aromatic compound according to the present invention can be used to produce not only the above-mentioned organic electroluminescent device but also an organic field effect transistor, an organic thin-film solar cell, or an organic photodiode (organic photodetector).

[0478] An organic field-effect transistor is a transistor that controls current by an electric field generated by voltage input, and has a gate electrode in addition to a source electrode and a drain electrode. When a voltage is applied to the gate electrode, an electric field is generated, and the transistor can control the current by arbitrarily blocking the flow of electrons (or holes) flowing between the source and drain electrodes. Field-effect transistors are easier to miniaturize than simple transistors (bipolar transistors), and are often used as elements that make up integrated circuits.

[0479] The structure of an organic field effect transistor is usually such that a source electrode and a drain electrode are provided in contact with an organic semiconductor active layer formed using the polycyclic aromatic compound according to the present invention, and a gate electrode is provided sandwiching an insulating layer (dielectric layer) in contact with the organic semiconductor active layer. Examples of the device structure include the following structure. (1) Substrate / gate electrode / insulating layer / source and drain electrodes / organic semiconductor active layer (2) Substrate / gate electrode / insulating layer / organic semiconductor active layer / source electrode / drain electrode (3) Substrate / organic semiconductor active layer / source electrode / drain electrode / insulator layer / gate electrode (4) Substrate / source electrode / drain electrode / organic semiconductor active layer / insulator layer / gate electrode The organic field effect transistor configured in this manner can be used as a pixel driving switching element for an active matrix driving liquid crystal display or an organic electroluminescence display.

[0480] An organic thin-film solar cell has a structure in which an anode such as ITO, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a cathode are laminated on a transparent substrate such as glass. The photoelectric conversion layer has a p-type semiconductor layer on the anode side and an n-type semiconductor layer on the cathode side. The polycyclic aromatic compound according to the present invention can be used as a material for the hole transport layer, p-type semiconductor layer, n-type semiconductor layer, or electron transport layer depending on its physical properties. The polycyclic aromatic compound according to the present invention can function as a hole transport material or electron transport material in an organic thin-film solar cell. In addition to the above, the organic thin-film solar cell may also include a hole blocking layer, electron blocking layer, electron injection layer, hole injection layer, smoothing layer, etc. as appropriate. Known materials used in organic thin-film solar cells can be appropriately selected and combined for use in the organic thin-film solar cell.

[0481] Organic photodiodes convert light into an electrical signal using organic materials and are used, for example, as organic light-receiving elements or organic photodetectors. For example, in organic photodetector applications, the polycyclic aromatic compound of the present invention can be used as a donor (or acceptor) in combination with a compound having acceptor (or donor) properties. After light is absorbed by these compounds, an excited state is transferred to the interface between the donor and acceptor compounds, inducing charge separation. The generated holes and electrons are then collected by the respective electrodes, generating a current that is detected as a signal. Furthermore, by utilizing the multiple resonance effect, the polycyclic aromatic compound of the present invention can also be applied to an organic photodiode containing the compound as a single component as a light absorber. For organic photodiodes, see, for example, Adv. Mater. 2024, 2414465, Adv. Mater. 2016, 28, 4766, Adv. Opt. Mater. 2024, 12, 2303216, Adv. Mater. 2016, 28, 2043, Nat.Commun. 2020, 11, 2871, Nano Lett. 2017, 17, 1995, Adv. Mater. 2017, 29, 1702184, Chem. Mater. 2021, 33, 5147, etc.

[0482] 3. Wavelength conversion materials The polycyclic aromatic compound of the present invention can be used as a wavelength converting material. Currently, the application of color conversion technology to multicolor displays, organic light-emitting diode (OLED) displays, and lighting is being actively investigated. Color conversion refers to the wavelength conversion of light emitted from a light emitter to light of a longer wavelength, such as converting ultraviolet or blue light to green or red light. By fabricating a film of wavelength conversion materials with this color conversion function and combining it with a blue light source, for example, it is possible to extract the three primary colors of blue, green, and red from the blue light source, i.e., white light. A white light source combining such a blue light source with a wavelength conversion film with color conversion functionality can be used as a light source unit, and combined with a liquid crystal driver and color filters, it is possible to create a full-color display. Furthermore, if the liquid crystal driver is not required, the white light source can be used as is, for example, in LED lighting. Furthermore, by combining a blue organic light-emitting diode (OLED) element as a light source with a wavelength conversion film that converts blue light to green and red, it is possible to fabricate a full-color OLED display without using a metal mask. Furthermore, by using blue microLEDs as a light source in combination with wavelength conversion films that convert blue light into green and red light, it becomes possible to create low-cost full-color microLED displays.

[0483] The polycyclic aromatic compound of the present invention can be used as this wavelength converting material. Using a wavelength converting material containing the polycyclic aromatic compound of the present invention, light from a light source or light-emitting device that generates ultraviolet light or blue light can be converted into green light with a color purity suitable for use in a display device (a display device using an organic EL device or a liquid crystal display device). The converted color can be adjusted by appropriately selecting the substituent of the polycyclic aromatic compound of the present invention, the binder resin used in the wavelength converting composition described below, etc. The wavelength converting material can be prepared as a wavelength converting composition containing the polycyclic aromatic compound of the present invention. Furthermore, this wavelength converting composition may be used to form a wavelength conversion film.

[0484] The wavelength-converting composition may contain, in addition to the polycyclic aromatic compound of the present invention, a binder resin, other additives, and a solvent. Examples of binder resins that can be used include those described in paragraphs

[0173] to

[0176] of WO 2016 / 190283. Examples of other additives that can be used include compounds described in paragraphs

[0177] to

[0181] of WO 2016 / 190283. For the solvent, the description of the solvent contained in the composition for forming an emitting layer can be referenced.

[0485] The wavelength conversion film includes a wavelength converting layer formed by curing a wavelength converting composition. Known film formation methods can be referred to as a method for producing a wavelength converting layer from a wavelength converting composition. The wavelength conversion film may consist solely of a wavelength converting layer formed from a composition containing the polycyclic aromatic compound of the present invention, or may also include other wavelength converting layers (e.g., a wavelength converting layer that converts blue light to green light or red light, or a wavelength converting layer that converts blue light or green light to red light). The wavelength conversion film may further include a substrate layer and a barrier layer to prevent deterioration of the color converting layer due to oxygen, moisture, or heat. [Example]

[0486] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0487] <<Synthesis Example>> Synthesis Example (1): Synthesis of Compound (1-391) First step [ka]

[0488] Under a nitrogen atmosphere, compound (S-1) (5.25 g, 4.0 mmol), 2,6-di-tert-butylpyridine (5.20 mL, 24.0 mmol), and chlorobenzene (40.0 mL) were placed in a Schlenk tube, and boron triiodide (12.6 g, 32.0 mmol) was added at 0°C. The reaction mixture was stirred at 50°C for 24 hours. Phosphate buffer solution (pH 6.8, 80 mL) was then added to the reaction mixture at 0°C. The aqueous layer was separated and extracted with dichloromethane (150 mL, 3 times). The combined organic layers were concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent: hexane / toluene = 1 / 1, ethyl acetate) and washed with hexane (30 mL) to obtain compound (S-2) (0.415 g, 0.31 mmol) as a yellow solid.

[0489] Second process [ka]

[0490] Under a nitrogen atmosphere, compound (S-2) (0.398 g, 0.3 mmol) obtained in the first step, 2,6-di-tert-butylpyridine (0.78 ml, 3.6 mmol), and o-dichlorobenzene (3.0 ml) were placed in a Schlenk tube, and boron tribromide (0.46 ml, 4.8 mmol) was added. The reaction mixture was stirred at 80°C for 1 hour, and then dichloromethane (10 ml) was added at 0°C. The reaction was quenched with phosphate buffer solution (pH = 6.8, 100 ml). The aqueous layer was separated and extracted with dichloromethane (30 ml, 3 times). The combined organic layers were concentrated under reduced pressure to obtain the crude product (0.483 g). Under a nitrogen atmosphere, the crude product (0.200 g) obtained above and aluminum chloride (0.149 g, 1.2 mmol) were placed in a Schlenk tube and dissolved in o-dichlorobenzene (1.5 mL) at 0 °C. The reaction mixture was stirred at 180 °C for 13 hours. The reaction was then terminated by adding phosphate buffer solution (pH = 6.8, 50 mL) at 0 °C, followed by extraction with toluene (30 mL, 3 times). The combined organic layer was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (eluent: hexane / dichloromethane = 3 / 2) to obtain the desired compound (1-391) as an orange solid (18.9 mg, 0.015 mmol).

[0491] The structure of the compound obtained was confirmed by NMR spectroscopy. 1 HNMR(CDCl3,500MHz):δ2.35(s,6H),2.38(s,6H), 2.41(s,12H),5.64(m,2H),6.68(s,4H),7.01-7.05(m,8H),7.11(d,J=7.9Hz,2H),7.19(d,J=7.7Hz, 2H),7.29(d,J=7.7Hz,4H),7.41(s,4H),7.99(t,J =7.1Hz,2H),8.77(d,J=7.9Hz,2H),8.83(d,J = 7.9Hz,2H),9.21(dd,J=7.2,1.6Hz,2H),9.33(dd,J=7.2,1.6Hz,2H),10.9(s,1H).

[0492] Synthesis Example (2): Synthesis of Compound (1-1) First step [ka]

[0493] Under a nitrogen atmosphere, compound (S-3) (1.20 g, 1.0 mmol), 2,6-di-tert-butylpyridine (1.30 mL, 6.0 mmol), and chlorobenzene (10.0 mL) were placed in a Schlenk tube, and boron triiodide (3.15 g, 8.0 mmol) was added at 0 °C. The reaction mixture was stirred at 50 °C for 24 hours. Phosphate buffer solution (pH = 6.8, 20 mL) was then added to the reaction mixture at 0 °C. The aqueous layer was separated and extracted with dichloromethane (100 mL, 3 times). The combined organic layers were concentrated under reduced pressure to give a residue, which was purified by silica gel column chromatography (eluent: hexane / toluene = 1 / 1, ethyl acetate) and washed with hexane (20 mL) to give compound (S-4) (159 mg, 0.13 mmol) as a yellow solid.

[0494] Second process [ka]

[0495] Under a nitrogen atmosphere, compound (S-4) (0.122 g, 0.10 mmol) obtained in the first step and o-dichlorobenzene (1.0 mL) were placed in a Schlenk tube, and boron triiodide (0.315 g, 0.80 mmol) was added at 0 °C. The reaction mixture was stirred at 140 °C for 14 hours. Phosphate buffer solution (pH = 6.8, 10 mL) was then added to the reaction mixture at 0 °C. The aqueous layer was separated and extracted with dichloromethane (20 mL, 3 times). The combined organic layers were concentrated under reduced pressure to give a residue, which was purified by silica gel column chromatography (eluent: hexane / toluene = 1 / 1, ethyl acetate) and then washed with hexane (10 mL) to give compound (1-1) (11 mg, 0.0089 mmol) as a yellow solid.

[0496] Synthesis Example (3): Synthesis of Compound (1-395) [ka]

[0497] Under a nitrogen atmosphere, compound (S-5) (0.134 g, 0.1 mmol), 2,6-di-tert-butylpyridine (0.259 ml, 1.2 mmol), and o-dichlorobenzene (2.5 ml) were placed in a Schlenk tube, and boron triiodide (0.626 g, 1.6 mmol) was added at 0 °C. The reaction mixture was stirred at 160 °C for 12 hours. The reaction mixture was then cooled to room temperature and diluted with dichloromethane. Phosphate buffer solution (pH = 6.8, 100 ml) was added at 0 °C. The aqueous layer was separated and extracted with dichloromethane (30 ml, 3 times). The combined organic layers were concentrated under reduced pressure, and the resulting residue was washed with acetonitrile, toluene, and dichloromethane to obtain compound (1-395) (35 mg, 0.025 mmol).

[0498] Compounds (1-2) to (1-15) were synthesized according to methods similar to Synthesis Example (1), Synthesis Example (2), and Synthesis Example (3). Comparative compound (R1-1) to compound (R1-6) were synthesized according to the method described in Synthesis Example (1) or WO 2018212169.

[0499] [ka]

[0500] [ka]

[0501] The formation of the target substance was confirmed by MALDI-TOF-MS (matrix-assisted laser desorption / ionization time-of-flight mass spectrometry).

[0502] [Table 1]

[0503] <<Production and Evaluation of Vapor-Deposited Organic EL Devices>> Using each of the synthesized compounds of the present invention and comparative compounds, organic EL devices of TADF, TAF, PSF, and TPSF were manufactured.

[0504] <TADF Configuration: Examples 1-1-1 to 1-1-17 and Comparative Examples 1-R1-1 to 1-R1-6> ITO (50 nm) / NPD (40 nm) / TcTa (15 nm) / mCP (15 nm) / DOBNA-Ph: Each compound described in Table 2 (99:1) (20 nm) / 3,4-2CzBN (10 nm) / BPy-TP2 (30 nm) / LiF (1 nm) / Al (100 nm) A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Opto Science Co., Ltd.) with ITO film formed to a thickness of 200 nm by sputtering and polished to 50 nm was used as the transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Vacuum Co., Ltd.), and molybdenum vapor deposition boats containing NPD, TcTa, mCP, DOBNA-Ph, 3,4-2CzBN, BPy-TP2, and each compound described in Table 2, and tungsten vapor deposition boats containing LiF and aluminum were mounted.

[0505] The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was 5×10 -4The pressure was reduced to Pa. First, NPD was heated and evaporated to a thickness of 40 nm to form a hole injection layer. Next, TcTa was heated and evaporated to a thickness of 15 nm to form a hole transport layer 1, and further, mCP was heated and evaporated to a thickness of 15 nm to form a hole transport layer 2. Next, DOBNA-mP and each compound described in Table 2 were heated simultaneously and evaporated to a thickness of 20 nm to form a light-emitting layer. The deposition rate was adjusted so that the mass ratio of DOBNA-Ph to each compound described in Table 2 was approximately 99 to 1. Next, 3,4-2CzBN was heated and evaporated to a thickness of 10 nm to form an electron transport layer 1, and further, BPy-TP2 was heated and evaporated to a thickness of 30 nm to form an electron transport layer 2. The deposition rate of each layer was 0.01 - 1 nm / second. Thereafter, LiF was heated and evaporated at a deposition rate of 0.01 - 0.1 nm / second to a thickness of 1 nm, and then, aluminum was heated and evaporated to a thickness of 100 nm to form a cathode, obtaining an organic EL device. At this time, the deposition rate of aluminum was adjusted to be 1 - 10 nm / second.

[0506] <TAF Configuration: Examples 2-1-1 to 2-1-17 and Comparative Examples 2-R1-1 to 2-R1-6> ITO(50 nm) / NPD(40 nm) / TcTa(15 nm) / mCP(15 nm) / mCBP:4CzIPN: Each compound described in Table 3 (79:20:1)(20 nm) / 3,4-2CzBN(10 nm) / BPy-TP2(30 nm) / LiF(1 nm) / Al(100 nm) Except for the light-emitting layer, it was fabricated in the same manner as the TADF configuration. In the light-emitting layer, mCBP, 4CzIPN, and each compound described in Table 3 were heated simultaneously and evaporated to a thickness of 20 nm. The deposition rate was adjusted so that the mass ratio of mCBP, 4CzIPN, and each compound described in Table 3 was approximately 79 to 20 to 1.

[0507] The chemical structures of the compounds used in the manufacture of the TADF device and the TAF device are shown below.

Chemical formula

[0508] <PSF structure: Examples 3-1-1 to 3-1-17 and Comparative Examples 3-R1-1 to 3-R1-6> ITO (50 nm) / HAT-CN (5 nm) / NPD (30 nm) / TcTa (10 nm) / CBP:Ir(ppy)2acac: each compound described in Table 4 (69:30:1) (30 nm) / 9Cz46m (10 nm) / p-bpphen (30 nm) / LiF (1 nm) / Al (100 nm) A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Opto Science Co., Ltd.) with ITO film formed to a thickness of 200 nm by sputtering and polished to 50 nm was used as the transparent support substrate. This transparent support substrate was fixed to the substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Vacuum Co., Ltd.), and molybdenum vapor deposition boats containing HAT-CN, NPD, TcTa, CBP, Ir(ppy)2acac, 9Cz46m, p-bpphen, and each compound described in Table 4, and tungsten vapor deposition boats containing LiF and aluminum were mounted respectively.

[0509] The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was 5×10 -4The pressure was reduced to Pa. First, HAT-CN was heated and evaporated to a thickness of 5 nm to form a hole injection layer. Next, NPD was heated and evaporated to a thickness of 30 nm to form a hole transport layer 1, and further TcTa was heated and evaporated to a thickness of 10 nm to form a hole transport layer 2. Next, CBP, Ir(ppy)2acac, and each compound described in Table 4 were simultaneously heated and evaporated to a thickness of 30 nm to form a light-emitting layer. The deposition rate was adjusted so that the mass ratio of CBP, Ir(ppy)2acac, and each compound described in Table 4 was approximately 69:30:1. Next, 9C46m was heated and evaporated to a thickness of 10 nm to form an electron transport layer 1, and further p-bpphen was heated and evaporated to a thickness of 30 nm to form an electron transport layer 2. The deposition rate of each layer was 0.01 - 1 nm / second. Thereafter, LiF was heated and evaporated at a deposition rate of 0.01 - 0.1 nm / second to a thickness of 1 nm, and then aluminum was heated and evaporated to a thickness of 100 nm to form a cathode, obtaining an organic EL device. At this time, the deposition rate of aluminum was adjusted to be 1 - 10 nm / second.

[0510] <TPSF configuration: Examples 4-1-1 to 4-1-17 and Comparative Examples 4-R1-1 to 4-R1-6> ITO(50 nm) / HAT-CN(5 nm) / NPD(30 nm) / TcTa(10 nm) / PCTF:Ir(ppy)2acac: each compound described in Table 5 (69:30:1)(30 nm) / 9Cz46m(10 nm) / p-bpphen(30 nm) / LiF(1 nm) / Al(100 nm) Except for the light-emitting layer, it was fabricated in the same manner as the PSF configuration. In the light-emitting layer, PCTF, Ir(ppy)2acac, and each compound described in Table 5 were simultaneously heated and evaporated to a thickness of 30 nm. The deposition rate was adjusted so that the mass ratio of PCTF, Ir(ppy)2acac, and each compound described in Table 5 was approximately 69:30:1.

[0511] The chemical structures of the compounds used in the manufacture of the above devices are shown below.

Chemical formula

[0512] [evaluation] The evaluation items include the driving voltage (V), emission wavelength (nm), CIE chromaticity (x, y), external quantum efficiency (%), maximum wavelength (nm) and half-width (nm) of the emission spectrum. 2 When illuminated or 10000cd / m 2 The value at the time of light emission can be used.

[0513] The quantum efficiency of a light-emitting element can be classified into internal quantum efficiency and external quantum efficiency, and the internal quantum efficiency indicates the rate at which external energy injected as electrons (or holes) into the light-emitting layer of the light-emitting element is converted purely into photons. On the other hand, the external quantum efficiency is calculated based on the amount of these photons that are emitted to the outside of the light-emitting element, and since some of the photons generated in the light-emitting layer are absorbed or continue to be reflected inside the light-emitting element and are not emitted to the outside of the light-emitting element, the external quantum efficiency is lower than the internal quantum efficiency.

[0514] The spectral radiance (emission spectrum) and external quantum efficiency were measured as follows: Using an Advantest voltage / current generator R6144, the device luminance was measured at 1000 cd / m 2 The device emits light by applying a voltage equal to the wavelength of the light emitted. Using a TOPCON SR-3AR spectroradiometer, the spectral radiance in the visible light region is measured perpendicular to the light-emitting surface. Assuming the light-emitting surface is a perfectly diffusing surface, the measured spectral radiance value for each wavelength component is divided by the wavelength energy and multiplied by π to obtain the number of photons at each wavelength. The number of photons is then integrated over the entire wavelength range observed to obtain the total number of photons emitted from the device. The applied current value divided by the elementary charge is the number of carriers injected into the device, and the total number of photons emitted from the device divided by the number of carriers injected into the device is the external quantum efficiency. The half-width of the emission spectrum is calculated as the width between the wavelengths above and below the maximum emission wavelength at which the intensity is 50%.

[0515] A DC voltage of 1000 cd / m was applied to the ITO electrode as the anode and the LiF / aluminum electrode as the cathode. 2 The characteristics of light emission were measured. In addition, the initial luminance was 1000 cd / m for the elements with the TADF configuration, TAF configuration, PSF configuration, and TPSF configuration. 2 The time (lifetime) during which the luminance is maintained at 50% or more of the luminance at the measured value was measured. The color (CIEy) can be calculated from the product of the spectral spectrum and the color-matching function, but in this example, it was output from an IVL (current-voltage-luminance characteristics evaluation device) for measuring current density, voltage, and luminance characteristics. The results are shown in Tables 2 to 5.

[0516] [Table 2]

[0517] [Table 3]

[0518] [Table 4]

[0519] [Table 5]

[0520] The results show that the devices of the examples have higher efficiency and / or longer life than the comparative examples, which use compounds with skeletons corresponding to the compounds of the examples. They also have larger CIEy values ​​and higher green color purity.

[0521] <<Evaluation of wavelength conversion characteristics>> <Sample preparation> The properties as wavelength conversion materials were evaluated by evaluating the emission spectrum shape and fluorescence quantum yield upon short wavelength excitation when dispersed in an optically inactive matrix.

[0522] Examples of matrix materials that can be used include commercially available acrylic resins such as PMMA (polymethyl methacrylate), cycloolefin polymers (COP), and polycarbonate (PC). For example, a thin film sample dispersed in PMMA can be prepared by dissolving commercially available PMMA powder and the target compound in toluene, spin-coating the sample onto a transparent support substrate (10 mm x 10 mm or 24 mm x 26 mm) made of quartz or non-alkali glass for optical analysis (OA-11, manufactured by Nippon Electric Glass Co., Ltd.), and drying at 100 °C for 10 minutes. Any size substrate can be used as long as the surface irradiated with the excitation light is uniform. For example, when spin-coating a non-alkali glass for optical analysis (OA-11, 26 mm x 24 mm) under the above conditions, the film thickness is 3–5 μm.

[0523] <Evaluation> The fluorescence spectrum of the sample was measured at room temperature under atmospheric pressure using a spectrofluorometer (Hitachi High-Tech Corporation, F-7000). The fluorescence quantum yield was also measured at room temperature under a nitrogen atmosphere using an absolute PL quantum yield measurement system (Hamamatsu Photonics K.K., C9920-02G).

[0524] <Example E-1-1: Compound (1-391)> A thin film substrate (made of quartz) was prepared by dispersing compound (1-391) in PMMA at a concentration of 1% by mass. The emission spectrum (Figure 2) and fluorescence quantum yield were then measured using 450 nm (blue) as excitation light. The maximum emission wavelength (peak wavelength) of the fluorescence spectrum was 509 nm (green), the half-width was 29 nm, and the fluorescence quantum yield was 88%. Compound (1-391) was able to efficiently convert blue excitation light into green emission with a narrow half-width.

[0525] <Example E-1-2: Compound (1-395)> A thin film substrate (made of quartz) was prepared by dispersing compound (1-395) in PMMA at a concentration of 1% by mass, and then the emission spectrum and fluorescence quantum yield were measured using 450 nm (blue) as excitation light. The maximum emission wavelength (peak wavelength) of the fluorescence spectrum was 522 nm (green), the half-width was 31 nm, and the fluorescence quantum yield was 90%. Compound (1-395) was able to efficiently convert blue excitation light into green emission with a narrow half-width.

[0526] <Comparative example C-1-1> A thin film substrate (made of quartz) was prepared by dispersing the compound (Ir(ppy)3) in PMMA at a concentration of 1% by mass. The emission spectrum (Figure 3) and fluorescence quantum yield were then measured using 450 nm (blue) excitation light. [ka] The maximum emission wavelength (peak wavelength) of the fluorescence spectrum was 507 nm (green), the half-width was 74 nm, and the fluorescence quantum yield was 88%. The compound (Ir(ppy)3) was able to efficiently convert blue excitation light into green emission with a wide half-width.

[0527] <Comparative example C-1-2> A thin film substrate (made of quartz) was prepared by dispersing compound (R1-2) in PMMA at a concentration of 1% by mass. The emission spectrum (Figure 4) and fluorescence quantum yield were then measured using 450 nm (blue) excitation light. The maximum emission wavelength (peak wavelength) of the fluorescence spectrum was 455 nm (blue), the half-width was 27 nm, and the fluorescence quantum yield was 60%. Compound (R1-2) was able to convert blue excitation light into blue emission with a narrow half-width, but was unable to convert it into green emission. The excitation light and emission peaks were very close, making it impossible to measure the fluorescence quantum yield correctly.

[0528] Table 6 shows the evaluation results of the wavelength conversion characteristics. [Table 6]

[0529] These results demonstrate that compounds (1-391) and (1-395) can more efficiently convert blue excitation light into green emission with a narrow half-width than compounds (Ir(ppy)3) and (R1-2). Green emission with a narrow half-width leads to high color purity and a wide color gamut coverage. [Industrial Applicability]

[0530] The polycyclic aromatic compound of the present invention can be used in the production of organic devices such as organic electroluminescent elements. In particular, the polycyclic aromatic compound of the present invention is useful as a green light-emitting material, and can be used in organic electroluminescent elements that form green pixels in a display device that has organic electroluminescent elements as red, green, and blue pixels. [Explanation of symbols]

[0531] 100 Organic electroluminescent device 101 Substrate 102 Anode 103 Hole injection layer 104 Hole transport layer 105 Light-emitting layer 106 Electron transport layer 107 Electron injection layer 108 Cathode

Claims

1. A polycyclic aromatic compound represented by formula (1); 【Chemical 1】 In formula (1), ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K each independently represent a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; Ring A and ring B may be bonded to each other via a single bond or a linking group; Ring B and ring C may be bonded to each other via a single bond or a linking group; ring E and ring G may be bonded to each other via a single bond or a linking group; Ring I and ring J may be bonded to each other via a single bond or a linking group; The ring J and the ring K may be bonded to each other via a single bond or a linking group; Each Z is independently ═C(R Ｚ )- or ═N-, and R Ｚ is hydrogen or a substituent, X １ and X ２ are each independently >N-R ＮＸ , >O, >C(-R ＣＸ ) ２ , >Si(-R ＩＸ ) ２ , >S, or >Se, and R ＮＸ is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; R ＣＸ and R ＩＸ are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl; ＣＸ may be bonded to each other to form a ring, and two R ＩＸ may be bonded to each other to form a ring, and X １ R in ＮＸ , R ＣＸ and R ＩＸ may be bonded to at least one of ring C and ring d via a linking group or a single bond, and X ２ R in ＮＸ , R ＣＸ and R ＩＸ may be bonded to at least one of ring h and ring I via a linking group or a single bond, At least one selected from the group consisting of an aryl ring and a heteroaryl ring in formula (1) may be condensed with at least one cycloalkane, and the cycloalkane may be substituted with at least one substituent, and at least one -CH ２ - may be replaced by -O-, At least one hydrogen atom in formula (1) may be replaced by a deuterium atom, and at least one nitrogen atom may be replaced by a nitrogen-15 atom ( １５ N), and at least one sulfur may be replaced by sulfur-33 ( ３３ S), sulfur-34 ( ３４ S) or sulfur-36 ( ３６ S), at least one oxygen is oxygen-17 ( １７ O) or oxygen-18 ( １８ O), at least one carbon is carbon-13 ( １３ C), at least one boron is boron-11 ( １１ B) may be substituted.

2. 2. The polycyclic aromatic compound according to claim 1, wherein ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted aryl ring, a substituted or unsubstituted benzofuran ring, or a substituted or unsubstituted benzothiophene ring, and the benzofuran ring and the benzothiophene ring are each bonded to boron at a ring-constituting atom of a five-membered ring.

3. 2. The polycyclic aromatic compound according to claim 1, wherein ring A, ring B, ring C, ring E, ring G, ring I, ring J, and ring K are each independently a substituted or unsubstituted benzene ring.

4. X １ and X ２ However, each independently >N-R ＮＸ , >O, or >S.

5. The polycyclic aromatic compound according to claim 1, which satisfies at least one of (B-1) to (B-7): (B-1)X １ But > N-R ＮＸ and X １ R in ＮＸ is bonded to ring C or ring d via a single bond or a linking group; (B-2) X ２ But > N-R ＮＸ and X ２ R in ＮＸ is bonded to ring I or ring h via a single bond or a linking group; (B-3) Ring A and ring B are bonded to each other via a single bond or a linking group; (B-4) Ring B and ring C are bonded to each other via a single bond or a linking group; (B-5) Ring E and ring G are bonded to each other via a single bond or a linking group; (B-6) Ring I and ring J are bonded to each other via a single bond or a linking group; (B-7) The J ring and the K ring are bonded to each other via a single bond or a linking group.

6. The polycyclic aromatic compound according to claim 1, which contains a group represented by formula (1L) as a partial structure. 【Chemistry 2】 In formula (1L), * indicates the bond position, Ring L is a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; R L is a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted arylthio, a substituted or unsubstituted heteroarylthio, a substituted or unsubstituted aryloxy, a substituted or unsubstituted heteroaryloxy, a substituted alkyl, an unsubstituted alkyl having 3 to 24 carbon atoms, or a substituted or unsubstituted cycloalkyl.

7. The polycyclic aromatic compound according to claim 1, represented by any one of the following formulas: 【Chemistry 3】 【Chemistry 4】

8. An organic electroluminescence device comprising a pair of electrodes consisting of an anode and a cathode and an organic layer disposed between the pair of electrodes, wherein the organic layer contains the polycyclic aromatic compound according to any one of claims 1 to 7.

9. The organic electroluminescent device according to claim 8 , wherein the organic layer is a light-emitting layer.

10. 10. The organic electroluminescent device according to claim 9, wherein the light-emitting layer comprises a host material, a thermally activated delayed fluorescent material or a phosphorescent material as an assisting dopant, and the polycyclic aromatic compound as an emitting dopant.

11. A display device or a lighting device comprising the organic electroluminescent device according to claim 8.

12. A wavelength converting material comprising the polycyclic aromatic compound according to any one of claims 1 to 7.

13. An organic photodiode comprising the polycyclic aromatic compound according to any one of claims 1 to 7.

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