Polycyclic aromatic compound, material for organic device, organic electroluminescent element, display device, and lighting device

Abstract

Provided are: a polycyclic aromatic compound; a novel compound which is effectively used as a material for an organic device such as an organic EL element; an organic electroluminescent element; a display device; a polycyclic aromatic compound represented by formula (1); at least one of rings A to C is a ring represented by formula (G), the others are aryl rings, Y1 is > B-, X1 and X2 are > O, > S, or > Se, at least one hydrogen atom in formula (1) may be substituted by deuterium, in formula (G), any two or three consecutive Zg are carbons bonded to Y1 and X1 and X2, and the others Zg are-N = or-C (-Rg) =, Rg is hydrogen or a substituent, L1 and L2 are both hydrogen, and X is a hydrogen atom or a substituent. Or two L1 and two L2 are respectively bonded with each other to form a single bond or > O, and W is C or Si. The polycyclic aromatic compound can be used for manufacturing a display device and a lighting device. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a polycyclic aromatic compound. In addition, the present invention relates to an organic device such as an organic electroluminescent element, an organic field effect transistor, and an organic thin film solar cell using the polycyclic aromatic compound, as well as a display device and a lighting device. The present invention also relates to a polycyclic aromatic compound, a material for an organic device, an organic electroluminescent element, a display device, and a lighting device. Background Art

[0002] In the past, display devices using light-emitting elements that perform electroluminescence have been studied in various ways because they can achieve power saving or thinning, and organic electroluminescent elements containing organic materials have been actively studied because they can be easily lightweight or large-scaled. In particular, the development of organic materials having light-emitting properties such as blue or green, which are one of the three primary colors of light, and the development of organic materials having charge transport capabilities including holes, electrons, etc. (having the possibility of becoming semiconductors or superconductors) have been actively studied so far, regardless of whether they are polymer compounds or low molecular weight compounds.

[0003] An organic electroluminescence (EL) element has a structure including a pair of electrodes including an anode and a cathode, and one or more layers disposed between the pair of electrodes and including an organic compound. The layers including the organic compound include a light-emitting layer, a charge transport / injection layer for transporting or injecting charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

[0004] As a light-emitting material for a light-emitting layer, for example, a material obtained by improving an azaborine derivative has been reported (Patent Document 1).

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] International Publication No. 2015 / 102118 Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] As described above, various materials have been developed as materials used in organic EL elements, but in order to increase the selection of materials for organic EL elements, it is desired to develop a material containing a compound different from the previous ones. In particular, a material that can further improve the performance of organic devices such as organic EL elements or a material that improves the manufacturing process is required.

[0010] An object of the present invention is to provide a novel compound which can be effectively used as a material for an organic device such as an organic EL element.

[0011] [Technical means to solve the problem]

[0012] The inventors have made great efforts to solve the above problems and found that polycyclic aromatic compounds with novel boron-containing skeletons have favorable properties as materials for organic devices. Based on this insight, multiple studies were further conducted to complete the present invention. That is, the present invention provides the following polycyclic aromatic compounds, and further provides materials for organic devices containing the following polycyclic aromatic compounds.

[0013] <1> A polycyclic aromatic compound represented by formula (1);

[0014] [Chemistry 1]

[0015]

[0016] In formula (1),

[0017] Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, wherein at least one of Ring A, Ring B and Ring C is a ring represented by Formula (G);

[0018] Y 1 For >B-, >P-, >P(=O)-, >P(=S)-, >Al-, >Ga-, >As-, >Si(-R IY )-, or>Ge(-R GY )-,

[0019] R IY and R GY are each independently a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl, or a substituted or unsubstituted cycloalkyl;

[0020] X 1 and X 2 Each independently is >NR NX 、>O、>S、>C(-R CX )2、>Si(-R IX )2, or>Se, R NX , 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, and the two R CX Can bond to each other to form a ring, two R IXCan bond to each other to form a ring,

[0021] R NX , R CX and R IX may be independently bonded to at least one of the A ring, the B ring, and the C ring via a linking group or a single bond;

[0022] In formula (G),

[0023] Any two or three consecutive Z g For Y 1 and X 1 and X 2 or X 1 or X 2 Bonded carbon,

[0024] Other Z g are independently -N= or -C(-R g )=,R g are each independently hydrogen or a substituent,

[0025] Two adjacent R g may be bonded to each other and, together with the carbon atoms to which they are bonded, form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring;

[0026] L 1 Both are hydrogen, or two L 1 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2、>S or >Se, L 2 Both are hydrogen, or two L 2 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2. >S or >Se,

[0027] R NL and R IL are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IL Can bond to each other to form a ring,

[0028] W is C or Si;

[0029] In formula (1), at least one hydrogen may be substituted with deuterium, and at least one nitrogen may be substituted with nitrogen-15( 15 N) substituted, at least one sulfur may be replaced by sulfur-33( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36S), at least one oxygen may be replaced by oxygen-17( 17 O) or oxygen-18 ( 18 O) substituted, at least one carbon may be substituted by carbon-13 ( 13 C) substituted, at least one boron may be substituted by boron-11( 11 B) Replacement.

[0030] <2> The polycyclic aromatic compound according to <1>, wherein Y 1 is>B-.

[0031] <3> The polycyclic aromatic compound according to <1> or <2>, wherein X 1 and X 2 are respectively independently >O, >S or >Se.

[0032] <4> The polycyclic aromatic compound according to any one of <1> to <3>, wherein other Z g All are -C(-R g )=, and R g are hydrogen, or

[0033] Other Z g All are -C(-R g )=, any adjacent set of two R g are bonded to each other and together with the carbon atoms to which they are bonded form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, except that R g All are hydrogen.

[0034] <5> The polycyclic aromatic compound according to any one of <1> to <4>, wherein two L 2 They bond to each other to form single bonds, >O or >S.

[0035] <6> The polycyclic aromatic compound according to any one of <1> to <5>, wherein the ring B is a ring represented by formula (G).

[0036] <7> The polycyclic aromatic compound according to <6>, which is represented by any of the following formulas.

[0037] [Chemistry 2]

[0038]

[0039] <8> The polycyclic aromatic compound according to any one of <1> to <5>, wherein the ring A is a ring represented by formula (G).

[0040] <9> The polycyclic aromatic compound according to <8>, which is represented by the following formula.

[0041] [Chemistry 3]

[0042]

[0043] <10> A material for an organic device, comprising the polycyclic aromatic compound according to any one of <1> to <9>.

[0044] <11> An organic electroluminescent element comprising: a pair of electrodes including an anode and a cathode; and an organic layer disposed between the pair of electrodes, the organic layer containing the polycyclic aromatic compound according to any one of <1> to <9>.

[0045] <12> The organic electroluminescent element according to <11>, wherein the organic layer is an electron transport layer.

[0046] <13> A display device or a lighting device, comprising the organic electroluminescent element according to <11> or <12>.

[0047] [Effects of the Invention]

[0048] According to the present invention, there is provided a novel polycyclic aromatic compound which is effectively used as a material for an organic device such as an organic electroluminescent element. The polycyclic aromatic compound of the present invention can be used to produce an organic device such as an organic electroluminescent element. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic cross-sectional view showing an example of an organic electroluminescent element.

[0050] [Explanation of Symbols]

[0051] 100: Organic electroluminescent element

[0052] 101: Substrate

[0053] 102: Anode

[0054] 103: Hole injection layer

[0055] 104: Hole transport layer

[0056] 105: Luminous layer

[0057] 106: Electron transport layer

[0058] 107: Electron injection layer

[0059] 108: Cathode DETAILED DESCRIPTION

[0060] Hereinafter, the present invention will be described in detail. The description of the constituent elements described below is sometimes based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range represented by "~" refers to the range including the numerical values ​​described before and after "~" as the lower limit and the upper limit. In addition, in this specification, the "hydrogen" in the description of the structural formula refers to "hydrogen atom (H)". Similarly, "carbon atom (C)" is sometimes referred to as "carbon".

[0061] In the present specification, "adjacent groups" refer to two groups respectively bonded to two adjacent atoms (two atoms directly bonded by a covalent bond) in a structural formula.

[0062] In the present specification, "Me" represents a methyl group, "Et" represents an ethyl group, "nBu" represents a normal butyl group, "tBu" represents a tertiary butyl group, "iBu" represents an isobutyl group, "secBu" represents a secondary butyl group, "nPr" represents a normal propyl group, "iPr" represents an isopropyl group, "tAm" represents a tert-amyl group, "2EH" represents a 2-ethylhexyl group, "tOct" represents a tert-octyl group, "Ph" represents a phenyl group, "Mes" represents mesityl (2,4,6-trimethylphenyl), "Ad" represents a 1-adamantyl group, "Tf" represents a trifluoromethanesulfonyl group, "TMS" represents a trimethylsilyl group, and "D" represents a deuterium group.

[0063] In this specification, an organic electroluminescent element may be referred to as an organic EL element.

[0064] In this specification, the chemical structure or substituent is sometimes represented by the carbon number, but the carbon number when the chemical structure is substituted with a substituent, or when the substituent is further substituted with a substituent, etc., refers to the carbon number of the chemical structure or the substituent, and does not refer to the total carbon number of the chemical structure and the substituent, or the total carbon number of the substituent and the substituent. For example, the so-called "substituent B with carbon number Y substituted by substituent A with carbon number X" means that "substituent A with carbon number X" is substituted on "substituent B with carbon number Y", and the carbon number Y is not the total carbon number of substituent A and substituent B. In addition, for example, the so-called "substituent B with carbon number Y substituted by substituent A" means that "substituent A (without carbon number limitation)" is substituted on "substituent B with carbon number Y", and the carbon number Y is not the total carbon number of substituent A and substituent B.

[0065] <Description of Ring and Substituent>

[0066] First, the details of the rings and substituents used in the present specification are described below.

[0067] Examples of the “aryl ring” in the present specification include 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.

[0068] Specific examples of the "aryl ring" include a benzene ring that is a monocyclic ring system, a biphenyl ring that is a bicyclic ring system, a naphthalene ring and an indene ring that are a condensed bicyclic ring system, a terphenyl ring (meta-terphenyl, o-terphenyl, p-terphenyl) that is a tricyclic ring system, an acenaphthene ring, fluorene ring, phenanthren ring, anthracene ring that are a condensed tricyclic ring system, a triphenylene ring, a pyrene ring, a tetracene ring, The ring is a perylene ring, a pentacene ring, etc. of a condensed five-ring system. In addition, the fluorene ring, the benzofluorene ring, and the indene ring also include structures in which the fluorene ring, the benzofluorene ring, the cyclopentane ring, etc. are spiro-bonded. In addition, the fluorene ring, the benzofluorene ring, and the indene ring also include rings in which two of the two hydrogen atoms of the methylene group in the structure are replaced by alkyl groups such as methyl groups described later as the first substituent to form dimethylfluorene rings, dimethylbenzofluorene rings, dimethylindene rings, etc.

[0069] As the "heteroaryl ring" in the present specification, for example, a heteroaryl ring having 2 to 30 carbon atoms can be mentioned, preferably a heteroaryl ring having 2 to 25 carbon atoms, more preferably a heteroaryl ring having 2 to 20 carbon atoms, further preferably a heteroaryl ring having 2 to 15 carbon atoms, and particularly preferably a heteroaryl ring having 2 to 10 carbon atoms. In addition, as the "heteroaryl ring", for example, a heterocyclic ring containing 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, selenium, phosphorus, and tellurium as ring-constituting atoms other than carbon can be mentioned.

[0070] 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 phenoxathiol 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, Thiophene ring, benzothiophene ring, dibenzothiophene ring, thianthrene ring, indolecarbazole ring, benzindolecarbazole ring, dibenzoindolecarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, dibenzodioxin ring, dioxaborinaphthoanthracene ring (5,9-dioxa-13b-bora-13bH-naphtho[3,2,1-de]anthracene) ring, etc.), benzoselenophene ring, dibenzoselenophene ring, azacarbazole ring, azadibenzothiophene ring, azadibenzofuran ring, azadibenzoselenophene ring, azatriphenylene ring, imidazoimidazole ring, indoloindole ring, benzofuranocarbazole ring, benzothiophenocarbazole ring, indenocarbazole ring and selenophenecarbazole ring, spiro[fluorene-9,9'-xanthene] ring, spirobis[siliconfluorene] ring, etc. In addition, among the dihydroacridine ring, xanthene ring and thioxanthene ring, two of the two hydrogen atoms of the methylene group in the structure are preferably substituted with an alkyl group such as a methyl group as described later as the first substituent to form a dimethyldihydroacridine ring, a dimethylxanthene ring, a dimethylthioxanthene ring, etc. In addition, bipyridine ring, phenylpyridine ring, pyridylphenyl ring as a bicyclic ring system, terpyridine ring, bipyridylphenyl ring, pyridylbiphenyl ring as a tricyclic ring system can also be listed as a "heteroaryl ring". In addition, the "heteroaryl ring" also includes a pyran ring.

[0071] In this specification, a substituent may be substituted with a further 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 further substituent or is unsubstituted. In the same sense, it is sometimes referred to as "substitutable". In this specification, the specific substituent at this time may be referred to as a "first substituent" and the further substituent may be referred to as a "second substituent".

[0072] In the present specification, the substituent group Z includes:

[0073] The aryl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group,

[0074] The heteroaryl group may be substituted by at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen.

[0075] The diarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two aryl groups in the diarylamino group may be bonded to each other via a linking group.

[0076] The diheteroarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two heteroaryl groups in the diheteroarylamino group may be bonded to each other via a linking group.

[0077] The arylheteroarylamino group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the aryl group and the heteroaryl group in the arylheteroarylamino group may be bonded to each other via a linking group.

[0078] The diarylboryl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group, and the two aryl groups in the diarylboryl group may be bonded via a single bond or a linking group.

[0079] The alkyl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, a cycloalkyl group, a cyano group and a halogen group,

[0080] The cycloalkyl group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group and a halogen group,

[0081] The alkoxy group may be substituted by at least one group selected from the group consisting of an aryl group, a heteroaryl group, a cycloalkyl group, a cyano group and a halogen group,

[0082] The aryloxy group may be substituted by at least one group selected from the group consisting of aryl, heteroaryl, alkyl, cycloalkyl, cyano and halogen.

[0083] Substituted silyl, cyano and halogen.

[0084] The aryl group as the second substituent in each group of the substituent group Z may be further substituted by an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group or a halogen. Similarly, the heteroaryl group as the second substituent may be substituted by an aryl group, a heteroaryl group, an alkyl group, a cycloalkyl group, a cyano group or a halogen.

[0085] In the present specification, when a "substituent" is referred to, unless otherwise specified, it may be any group selected from the substituent group Z. For example, when a "substituted or unsubstituted" group is substituted, the group may be substituted with at least one group selected from the substituent group Z.

[0086] In the present specification, the "aryl group" is, for example, an aryl group having 6 to 30 carbon atoms, and preferably an aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aryl group having 6 to 10 carbon atoms.

[0087] Specific examples of the "aryl group" include a monovalent group obtained by removing one hydrogen atom from the above-mentioned "aryl ring". For example, it is a phenyl group which is a monocyclic ring, a biphenyl group (2-biphenyl, 3-biphenyl, or 4-biphenyl) which is a bicyclic ring, a naphthyl group (1-naphthyl or 2-naphthyl) which is a condensed bicyclic ring, a terphenyl group (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) which is a tricyclic ring, a condensed tricyclic acenaphthene group (1-, 3-, 4-, or 5- The invention also includes the following: a 1-, 2-, 3-, 4-, or 9-) group, a phenanthren-(1-, 2-, 3-, 4-, or 9-) group, a tetraphenyl group (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, or m-quaterphenyl group) having a tetracyclic ring system, a triphenylene-(1-, 2-, or 4-) group, a pyrene-(1-, 2-, or 4-) group, or a tetracene-(1-, 2-, or 5-) group having a condensed tetracyclic ring system, or a perylene-(1-, 2-, or 3-) group, or a pentacene-(1-, 2-, 5-, or 6-) group having a condensed pentacyclic ring system. In addition, a monovalent group of spirofluorene and the like can be mentioned.

[0088] In addition, the aryl group serving as the second substituent also includes a structure in which the aryl group is substituted by at least one group selected from the group consisting of aryl groups such as phenyl (specific examples are the groups described above), alkyl groups such as methyl (specific examples are the groups described later), and cycloalkyl groups such as cyclohexyl or adamantyl (specific examples are the groups described later).

[0089] As an example thereof, there can be mentioned a group in which the 9-position of the fluorenyl group as the second substituent is substituted with an aryl group such as a phenyl group, an alkyl group such as a methyl group, or a cycloalkyl group such as a cyclohexyl group or an adamantyl group.

[0090] The “arylene group” is, for example, an arylene group having 6 to 30 carbon atoms, and preferably an arylene group having 6 to 20 carbon atoms, an arylene group having 6 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, or an arylene group having 6 to 10 carbon atoms.

[0091] Specific examples of the "arylene group" include a divalent group obtained by removing one hydrogen atom from the above-mentioned "aryl group" (monovalent group).

[0092] The “heteroaryl group” is, for example, a heteroaryl group having 2 to 30 carbon atoms, preferably a heteroaryl group having 2 to 25 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, a heteroaryl group having 2 to 15 carbon atoms, or a heteroaryl group having 2 to 10 carbon atoms. The “heteroaryl group” contains, in addition to carbon atoms, one or more, preferably one to five heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms.

[0093] Specific examples of "heteroaryl" include monovalent groups formed by removing one hydrogen from the "heteroaryl ring". Examples include 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, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathiol, phenoxazinyl, phenanthrolinyl, phenanthroline ... Thiazinyl, phenazinyl, phenazasilinyl, indolizinyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, naphthobenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, naphthobenzothienyl, a monovalent group of a benzophospholine oxide ring, a monovalent group of a dibenzophospholine oxide ring, furazanyl, thianthrenyl, indolecarbazolyl, benzindolecarbazolyl, dibenzoindolecarbazolyl, imidazolinyl, or oxazolinyl, etc. In addition, a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirobis[silafluorene], and a monovalent group of benzoselenophene can be mentioned.

[0094] In addition, the heteroaryl group as the second substituent also includes a structure in which the heteroaryl group is substituted by at least one group selected from the group consisting of aryl groups such as phenyl (specific examples are the groups described above), alkyl groups such as methyl (specific examples are the groups described later), and cycloalkyl groups such as cyclohexyl or adamantyl (specific examples are the groups described later).

[0095] As an example, the 9-position of the carbazolyl group as the second substituent is substituted by an aryl group such as a phenyl group, an alkyl group such as a methyl group, or a cycloalkyl group such as a cyclohexyl group or an adamantyl group. In addition, a nitrogen-containing heteroaryl group such as a pyridyl group, a pyrimidyl group, a triazine group, a carbazolyl group, etc., which is further substituted by a phenyl group or a biphenyl group, is also included in the heteroaryl group as the second substituent.

[0096] The “heteroarylene group” is, for example, a heteroarylene group having 2 to 30 carbon atoms, preferably a heteroarylene group having 2 to 25 carbon atoms, a heteroarylene group having 2 to 20 carbon atoms, a heteroarylene group having 2 to 15 carbon atoms, or a heteroarylene group having 2 to 10 carbon atoms. In addition, the “heteroarylene group” is, for example, a divalent group such as a heterocycle containing 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen as ring-constituting atoms in addition to carbon.

[0097] Specific examples of the "heteroarylene group" include a divalent group obtained by removing one hydrogen atom from the above-mentioned "heteroaryl group" (monovalent group).

[0098] The "diarylamino group" is an amino group substituted with two aryl groups, and the description of the above-mentioned "aryl group" can be referred to for details of the aryl group.

[0099] The "diheteroarylamino group" is an amino group substituted with two heteroaryl groups, and the description of the "heteroaryl group" can be referred to for details of the heteroaryl group.

[0100] The "arylheteroarylamino group" is an amino group substituted with an aryl group or a heteroaryl group, and the description of the above-mentioned "aryl group" and "heteroaryl group" can be cited for the details of the above-mentioned aryl group and heteroaryl group.

[0101] The two aryl groups in the diarylamino group as the first substituent may be bonded to each other via a linking group, the two heteroaryl groups in the diheteroarylamino group as the first substituent may be bonded to each other via a linking group, and the aryl and heteroaryl groups in the arylheteroarylamino group as the first substituent may be bonded to each other via a linking group. Here, the description of "bonding via a linking group" is as shown below, for example, it means that the two phenyl groups of the diphenylamino group form a bond through a linking group. In addition, the description is also applicable to the diheteroarylamino group and the arylheteroarylamino group formed by aryl or heteroaryl groups.

[0102] [Chemistry 4]

[0103] (* indicates the bond position)

[0104] Specific examples of the linking group include: >O, >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 independently alkyl, cycloalkyl, aryl, or heteroaryl, which may be substituted by alkyl, cycloalkyl, aryl, or heteroaryl. X)2. -C(-R X )=C(-R X )-、>Si(-R X )2 Each of the two R X Can be linked to the group X via a single bond or Y bond to each other to form a ring. Y , can be listed as >O, >NR Y 、>C(-R Y )2、>Si(-R Y )2, >S, >CO, >CS, >SO, >SO2, and >Se, R Y are independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted by alkyl, cycloalkyl, aryl or heteroaryl. Y is>C(-R Y )2 and>Si(-R Y )2, the two R Y The alkylene group may be substituted with an alkylene group. 2X Replacement, R 2X are independently alkyl, cycloalkyl, substituted silyl, aryl and heteroaryl, which may be substituted by alkyl, cycloalkyl, substituted silyl or aryl. X )=C(-R X )-The two Rs in X They may be bonded to each other and form an aryl ring (such as a benzene ring) or a heteroaryl ring together with these bonded C=C. X )=C(-R X )- can be an arylene group (such as 1,2-phenylene) or a heteroarylene group.

[0105] In addition, when simply describing “diarylamino”, “diheteroarylamino” or “arylheteroarylamino” in the present specification, unless otherwise specified, descriptions such as “two aryl groups in the diarylamino group may be bonded to each other via a linking group”, “two heteroaryl groups in the diheteroarylamino group may be bonded to each other via a linking group” and “the aryl and heteroaryl groups in the arylheteroarylamino group may be bonded to each other via a linking group” are respectively added.

[0106] "Diarylboryl" is a boron group substituted with two aryl groups, and the details of the aryl group can be referred to the description of the "aryl group". In addition, the two aryl groups may be bonded via a single bond or a linking group (for example, -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 of -CR=CR-, R of >NR, R of >B(-R), R of >C(-R)2, and R of >Si(-R) are aryl, heteroaryl, diarylamino, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen in the R may be further substituted by an aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. In addition, two adjacent Rs may be bonded to each other to form a ring, thereby forming a cycloalkylene, arylene, and heteroarylene. For details of the substituents listed here, the descriptions of "aryl", "arylene", "heteroaryl", "heteroarylene", and "diarylamino" described above, as well as the descriptions of "alkyl", "alkenyl", "alkynyl", "cycloalkyl", "cycloalkylene", "alkoxy", and "aryloxy" described later may be cited. In the present specification, when simply describing a "diarylboryl group", unless otherwise specified, it is assumed that "two aryl groups in the diarylboryl group may be bonded to each other via a single bond or a linking group" is included.

[0107] "Alkyl" can be any of straight chain and branched chain, for example, a straight chain alkyl group with 1 to 24 carbon atoms or a branched chain alkyl group with 3 to 24 carbon atoms, preferably an alkyl group with 1 to 18 carbon atoms (branched chain alkyl group with 3 to 18 carbon atoms), an alkyl group with 1 to 12 carbon atoms (branched chain alkyl group with 3 to 12 carbon atoms), an alkyl group with 1 to 6 carbon atoms (branched chain alkyl group with 3 to 6 carbon atoms), an alkyl group with 1 to 5 carbon atoms (branched chain alkyl group with 3 to 5 carbon atoms), an alkyl group with 1 to 4 carbon atoms (branched chain alkyl group with 3 to 4 carbon atoms), etc.

[0108] 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, sec-butyl, tert-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-dimethylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, tert-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, or n-icosyl.

[0109] The "alkylene group" is a divalent group obtained by removing any hydrogen atom from an "alkyl group", and examples thereof include a methylene group, an ethylene group, and a propylene group.

[0110] Regarding the "alkenyl group", please refer to the description of the "alkyl group". It is a group in which the CC single bond in the structure of the "alkyl group" is replaced by a C=C double bond, and also includes a group in which not only one but more than two single bonds are replaced by double bonds (also called a diene group or a triene group).

[0111] The "alkenylene group" is a divalent group obtained by removing any hydrogen atom of an "alkenyl group", and examples thereof include a vinylene group.

[0112] Regarding the “alkynyl group”, reference may be made to the description of the “alkyl group”, which is a group in which the C-C single bond in the structure of the “alkyl group” is replaced by a C≡C triple bond, and also includes a group in which not only one but two or more single bonds are replaced by triple bonds (also called a di-alkynyl group or a tri-alkynyl group).

[0113] The “cycloalkyl group” is, for example, a cycloalkyl group having 3 to 24 carbon atoms, preferably a cycloalkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 16 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, a cycloalkyl group having 5 to 6 carbon atoms, or a cycloalkyl group having 5 carbon atoms.

[0114] Specific examples of "cycloalkyl" include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyl (especially methyl) substituents 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, diadamantyl, decahydronaphthyl, or decahydroazulyl.

[0115] The “cycloalkylene group” is, for example, a cycloalkylene group having 3 to 24 carbon atoms, preferably a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkylene group having 3 to 16 carbon atoms, a cycloalkylene group having 3 to 14 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a cycloalkylene group having 5 to 10 carbon atoms, a cycloalkylene group having 5 to 8 carbon atoms, a cycloalkylene group having 5 to 6 carbon atoms, or a cycloalkylene group having 5 carbon atoms.

[0116] Specific examples of the "cycloalkylene group" include a structure in which one hydrogen atom is removed from the above-mentioned "cycloalkyl group" (monovalent group) to give a divalent group.

[0117] The "cycloalkenyl group" includes a group having a structure in which at least one set of single bonds between two carbon atoms in the "cycloalkyl group" becomes a double bond (for example, a group in which -CH2-CH2- is substituted with -CH=CH-), and a group that is not equivalent to an aryl group. Specifically, 1-cyclohexenyl, 1-cyclopentenyl, etc. can be mentioned.

[0118] The "alkoxy group" is a group represented by "Alk-O-(Alk is an alkyl group)", and the description of the "alkyl group" can be cited for details of the alkyl group.

[0119] The "aryloxy group" is a group represented by "Ar-O-(Ar is an aryl group)", and the description of the "aryl group" can be cited for details of the aryl group.

[0120] The “substituted silyl group” is, for example, a silyl group substituted with at least one of an aryl group, an alkyl group, and a cycloalkyl group, and is preferably a triarylsilyl group, a trialkylsilyl group, a tricycloalkylsilyl group, a dialkylcycloalkylsilyl group, or an alkyldicycloalkylsilyl group.

[0121] The "triarylsilyl group" is a silyl group substituted with three aryl groups, and the description of the "aryl group" can be cited for details of the aryl groups.

[0122] Specific examples of the “triarylsilyl group” include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl groups.

[0123] The “trialkylsilyl group” is a silyl group substituted with three alkyl groups, and the description of the “alkyl group” mentioned above can be referred to for details of the alkyl groups.

[0124] Specific examples of “trialkylsilyl” include trimethylsilyl, triethylsilyl, tri-n-propylsilyl, triisopropylsilyl, tri-n-butylsilyl, triisobutylsilyl, tri-sec-butylsilyl, tri-tert-butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, sec-butyldimethylsilyl, tert-butyldimethylsilyl, methyldiethylsilyl, n-propyldimethylsilyl, tert-butyldiethylsilyl, methyldi-n-propylsilyl, ethyldi-n-propylsilyl, n-butyldi-n-propylsilyl, sec-butyldi-n-propylsilyl, tert-butyldi-n-propylsilyl, methyldiisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, sec-butyldiisopropylsilyl, or tert-butyldiisopropylsilyl.

[0125] The "tricycloalkylsilyl group" is a silyl group substituted with three cycloalkyl groups, and the description of the "cycloalkyl group" mentioned above can be cited for the details of the cycloalkyl group.

[0126] Specific examples of the “tricycloalkylsilyl group” include tricyclopentylsilyl and tricyclohexylsilyl groups.

[0127] The "dialkylcycloalkylsilyl group" is a silyl group substituted with two alkyl groups and one cycloalkyl group, and the description of the "alkyl group" and the "cycloalkyl group" can be cited for details of the alkyl group and the cycloalkyl group.

[0128] The "alkyldicycloalkylsilyl group" is a silyl group substituted with one alkyl group and two cycloalkyl groups, and the description of the "alkyl group" and the "cycloalkyl group" can be cited for details of the alkyl group and the cycloalkyl group.

[0129] The "halogen" is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, further preferably fluorine.

[0130] <When two groups bonded to the same atom are bonded to each other>

[0131] In the present specification, when it is mentioned that two groups bonded to the same atom can be bonded to each other to form a ring, they can be bonded via a single bond or a linking group (these are also collectively referred to as a bonding group). 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- or -Se-. For example, the following structures can be mentioned. In addition, the R of -CHR-CHR-, the R of -CR2-CR2-, the R of -CR=CR-, the R of -N(-R)-, the R of -C(-R)2-, the R of -B(-R)-, and the R of -Si(-R)2- are independently hydrogen, aryl which may be substituted by alkyl or cycloalkyl, heteroaryl which may be substituted by alkyl or cycloalkyl, alkyl which may be substituted by cycloalkyl, alkenyl which may be substituted by alkyl or cycloalkyl, alkynyl which may be substituted by alkyl or cycloalkyl, or cycloalkyl which may be substituted by alkyl or cycloalkyl. In addition, two adjacent Rs may be bonded to each other to form a ring, and may form a cycloalkylene group, an arylene group, or a heteroarylene group.

[0132] [Chemistry 5]

[0133]

[0134] As the bonding group, a single bond, -CR=CR-, -N(-R)-, -O-, -S-, -C(-R)2-, -Si(-R)2-, and -Se- are preferred as the linking group; a single bond, -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R)2- are more preferred as the linking group; a single bond, -CR=CR-, -N(-R)-, -O-, and -S- are further preferred as the linking group; and a single bond is most preferred.

[0135] The position at which the two Rs are bonded via a bonding group is not particularly limited as long as it is a position at which bonding is possible, but it is preferred that the two Rs are bonded at the most adjacent position. For example, when the two groups are phenyl groups, it is preferred that the two Rs are bonded to each other at the ortho position (position 2) based on the bonding position (position 1) of "C" or "Si" in the phenyl group (refer to the structural formula).

[0136] <Stereoisomers, etc.>

[0137] The polycyclic aromatic compound of the present invention may exist as enantiomers or diastereomers depending on the type of substituents, but any stereoisomer in any pure form, any mixture of stereoisomers, racemates, etc. are all included in the scope of the present invention regardless of the structural formula described.

[0138] 1. Polycyclic aromatic compounds

[0139] <Description of the overall structure of polycyclic aromatic compounds>

[0140] The polycyclic aromatic compound of the present invention is represented by formula (1).

[0141] [Chemistry 6]

[0142]

[0143] In formula (1),

[0144] Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, wherein at least one of Ring A, Ring B and Ring C is a ring represented by Formula (G).

[0145] Regarding polycyclic aromatic compounds formed by linking aromatic rings using heteroelements such as boron, nitrogen, oxygen, and sulfur, it has been found that they have a large highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap (band gap Eg in the film). The polycyclic aromatic compounds represented by formula (1) also have large Eg and electron mobility, and are therefore suitable for materials for electron transport layers. In addition, the polycyclic aromatic compounds represented by formula (1) have a higher Tg (glass transition temperature) than previously known polycyclic aromatic compounds by introducing a ring represented by formula (G), and the properties are not easily reduced when the film is formed at a practical temperature.

[0146] <Description of Ring Structure in Polycyclic Aromatic Compounds>

[0147] In formula (1), "A", "B", and "C" in the circles are symbols indicating the ring structures represented by the circles. The structure represented by formula (1) has a structure using Y 1 , X 1 and X 2 A structure in which at least three aromatic rings among the A ring, the B ring, and the C ring are linked to form a ring structure. The formed ring structure is a condensed ring structure composed of at least five rings.

[0148] Ring A forms a trivalent group having bonds on three consecutive elements (preferably carbon) on the aryl ring or heteroaryl ring in its structure. 1 , X 1 and X 2 In addition, the B ring and the C ring each form a divalent group having a bond on two adjacent elements (preferably carbon) on the aryl ring or heteroaryl ring in the structure. 1 , and X 1 or X 2 Bond.

[0149] In formula (1), at least one ring selected from the group consisting of ring A, ring B, and ring C is a ring represented by formula (G).

[0150] [Chemistry 7]

[0151]

[0152] In formula (G), any two or three consecutive Z g For Y 1 and X 1 and X 2 or X 1 or X 2 That is, when ring A is a ring represented by formula (G), any three consecutive Z g For X 1 , Y 1 and X 2 When the B ring is a ring represented by formula (G), any two consecutive Z g For Y 1 and X 1 When the C ring is a ring represented by formula (G), any two consecutive Z g For Y 1 and X 2 Bonded carbon.

[0153] With Y 1 , X 1 and X 2 Bonded Z g For example, when ring A is a ring represented by formula (G), Z at positions 1 to 3, 2 to 4, 5 to 7, or 6 to 8 below is g Become with X 1 , Y 1 and X 2 When the B ring is a ring represented by formula (G), Z at the 1-2, 2-3, 3-4, 5-6, 6-7 or 7-8 position below is g Become with Y1 and X 1 When the C ring is a ring represented by formula (G), Z at positions 1 to 2, 2 to 3, 3 to 4, 5 to 6, 6 to 7, or 7 to 8 below is g Become with Y 1 and X 2 In addition, depending on the structure of formula (G), 1 and 8, 2 and 7, 3 and 6, and 4 and 5 may be equivalent to each other.

[0154] [Chemistry 8]

[0155]

[0156] In formula (G), other Z than the above g are independently -N= or -C(-R g )=. Z for -N= g In each monocyclic ring in formula (G), the number of Z is preferably 0 to 2, more preferably 0 to 1, and even more preferably 0. g Preferably, both are -C(-R g )=.

[0157] R g are independently hydrogen or a substituent, and two adjacent R g They may be bonded to each other and together with the carbon atoms to which they are bonded to form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring.

[0158] As R g The substituents of include substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, substituted or unsubstituted diarylamino, substituted or unsubstituted diheteroarylamino, substituted or unsubstituted arylheteroarylamino, substituted or unsubstituted diarylboryl, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, substituted or unsubstituted arylthio, substituted silyl, cyano, and halogen. As the substituent, preferably substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, more preferably phenyl.

[0159] R g It is preferably hydrogen, or as described below, it is connected to an adjacent R g Bond.

[0160] Two adjacent R gThe two R bonded to each other may form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring together with the carbon atoms to which they are bonded. Examples of the aryl ring or heteroaryl ring formed include a benzene ring. g Together with the bonded ring, a naphthalene ring is formed. The formed benzene ring is preferably unsubstituted.

[0161] In formula (G), L 1 Both are hydrogen, or two L 1 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2, >S or >Se. In addition, L 2 Both are hydrogen, or two L 2 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2.>S or>Se.

[0162] R NL and R IL are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IL They can bond with each other to form a ring. NL It is preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and more preferably a substituted or unsubstituted phenyl group. IL Preferred is a substituted or unsubstituted aryl group or a substituted or unsubstituted alkyl group, and more preferred is a phenyl group or a methyl group.

[0163] In formula (G), preferably two L 2 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2, >S or >Se. In this case, it is more preferred that two L 2 Forming a single bond, >O or >S. Also preferably two L 2 When the two L 1 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2, >S or >Se. In this case, it is more preferred that two L 1 A single bond, >O or >S is formed.

[0164] In formula (G), W is C or Si, preferably C.

[0165] Specific examples of the ring represented by formula (G) are shown below.

[0166] [Chemistry 9]

[0167]

[0168] In formula (1), it is preferred that any one ring selected from the group consisting of ring A, ring B, and ring C is a ring represented by formula (G). Any one of ring A, ring B, and ring C may be a ring represented by formula (G). For example, ring A may be a ring represented by formula (G), and ring B may also be a ring represented by formula (G).

[0169] When ring A is not a ring represented by formula (G), the ring in which the element having the three bonding bonds is set as a ring constituent element in ring A is preferably a 5-membered ring or a 6-membered ring. The ring may further condense with other rings. As an example of a 6-membered ring, a benzene ring may be cited. As an example of a 6-membered ring further condensed with other rings, naphthalene ring, anthracene ring, quinoline ring, isoquinoline ring, quinazoline ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, etc. may be cited. As an example of a 5-membered ring, furan ring, thiophene ring, pyrrole ring, thiazole ring, etc. may be cited. As an example of a 5-membered ring further condensed with other rings, benzofuran ring, benzothiophene ring, indole ring, etc. may be cited.

[0170] The aryl ring or heteroaryl ring in the A ring is preferably a benzene ring.

[0171] When each ring of the B ring and the C ring is not a ring represented by formula (G), the ring in which the element having the two bonding bonds is set as a ring constituent element in each ring of the B ring and the C ring is preferably a 5-membered ring or a 6-membered ring. The ring can be further condensed with other rings. As examples of 6-membered rings, benzene rings, pyridine rings, etc. can be listed. As examples of 6-membered rings and other ring condensation, can be listed: naphthalene ring, quinoline ring, benzofuran ring, benzothiophene ring, indole ring, indene ring, benzoselenophene ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, dibenzoselenophene ring, etc. As examples of 5-membered rings, can be listed: furan ring, thiophene ring, pyrrole ring, thiazole ring, selenophene ring, etc. As examples of 5-membered rings and other ring condensation, can be listed: benzofuran ring, benzothiophene ring, indole ring, benzoselenophene ring, etc.

[0172] The aryl ring or heteroaryl ring in the B ring and the C ring is preferably a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, a thiazole ring, a benzofuran ring, a benzothiophene ring, a benzoselenophene ring or an indole ring, and more preferably a benzene ring.

[0173] In formula (1), in the substituted or unsubstituted aryl ring or substituted or unsubstituted heteroaryl ring in the A ring, the B ring and the C ring, as the substituent mentioned in "substituted or unsubstituted (substituted or unsubstituted)", in addition to the substituent selected from the substituent group Z, there can be substituted or unsubstituted alkenyl, substituted or unsubstituted arylthio, preferably substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, triarylsilyl or cyano. As the second substituent, methyl, trifluoromethyl, halogen, cyano and the like are also preferred.

[0174] From the viewpoint of synthesis and sublimation properties, it is preferred that the aryl ring or heteroaryl ring in the A ring, the B ring, and the C ring have no substituent.

[0175] <Y 1 >

[0176] In formula (1), Y 1 For >B-, >P-, >P(=O)-, >P(=S)-, >Al-, >Ga-, >As-, >Si(-R IY )-or>Ge(-R GY )-. R IY and R GY are each independently a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl, or a substituted or unsubstituted cycloalkyl. IY and R GY , particularly preferably an aryl group having 6 to 10 carbon atoms (e.g., phenyl, naphthyl, etc.), an alkyl group having 1 to 5 carbon atoms (e.g., methyl, ethyl, etc.), or a cycloalkyl group having 5 to 10 carbon atoms (preferably cyclohexyl or adamantyl).

[0177] Y 1 It is preferably >B-, >P(=O)- or >P(=S)-, and more preferably >B-.

[0178] <X 1 and X 2 >

[0179] X in formula (1) 1 and X 2 Each independently is >NR NX 、>O、>S、>C(-R CX )2、>Si(-R IX )2 or>Se.

[0180] R CX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two RCX They can bond with each other to form a ring. CX Preferably it is methyl or phenyl. IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IX They may bond with each other to form a ring.

[0181] R NX is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, preferably substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl.

[0182] X 1 and X 2 They are each independently preferably >O, >S or >Se, and are all more preferably >O.

[0183] <By X 1 or X 2 Explanation of changes in ring structure caused by bonding with the ring>

[0184] X 1 and X 2 R NX , at least one R CX , and at least one R IX The ring may be bonded to at least one of the A ring or the B ring or at least one of the A ring or the C ring via a single bond or a linking group.

[0185] As R NX , R CX and R IXExamples of the linking group when bonding to each 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- or -Se-. Among 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 still more preferred. R of "-CHR-CHR-", R of "-CR2-CR2-", R of "-CR=CR-", R of "-N(-R)-", R of "-C(-R)2-", and R of "-Si(-R)2-" are each independently hydrogen, aryl which may be substituted by alkyl or cycloalkyl, heteroaryl which may be substituted by alkyl or cycloalkyl, alkyl which may be substituted by alkyl or cycloalkyl, alkenyl which may be substituted by alkyl or cycloalkyl, alkynyl which may be substituted by alkyl or cycloalkyl, or cycloalkyl which may be substituted by alkyl or cycloalkyl. In addition, two Rs bonded to the same element may bond to each other to form a ring. Furthermore, two adjacent Rs may bond to each other to form a cycloalkylene ring, an arylene ring, and a heteroarylene ring. In addition, these rings may also be substituted by an alkyl group or a cycloalkyl group.

[0186] As >NR NX R NX Examples of the condensed ring formed by bonding with the benzene ring as an aryl ring in the A ring, the B ring or the C ring include: a carbazole ring (where R is a phenyl group); NX through a single bond), a phenoxazine ring (a phenyl group R NX through -O-bonding), phenothiazine ring (phenyl R NX through -S-bonding) or acridone ring (phenyl R NX through a -C(=O)- bond).

[0187] In addition, the following partial structure (A10) may be formed by the connection as described above.

[0188] [Chemistry 10]

[0189]

[0190] In formula (A10), R A1 ~R A4 are independently hydrogen, alkyl or cycloalkyl, R A1~R A4 Any two to four of the above may be bonded to each other via a linking group or a single bond, and may be bonded to X at the two * positions. 1 or X 2 One of the two rings bonded is bonded to the other ring at the ** position. That is, N in formula (A10) is X 1 or X 2 NR NX When>NR NX The atoms on the ring that are bonded at the two * positions only need to be adjacent atoms (preferably carbon atoms). When the polycyclic aromatic compound contains the structure represented by formula (A10), the number of the structures can be one or two (preferably one).

[0191] In formula (A10), R A1 ~R A4 Any two to four of may be linked to each other via a linking group or a single bond.

[0192] R A1 ~R A4 Preferably, 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 bonded to each other through a linking group or a single bond, and more preferably R A1 and R A4 They are bonded to each other through a linking group or a single bond. As divalent groups formed by mutual bonding, alkylene, cycloalkylene, etc. can be listed. At least one hydrogen in the alkylene can be substituted by an alkyl or cycloalkyl group, and at least one (preferably one) -CH2- in the alkylene can be substituted by -O- and -S-. As divalent groups formed by mutual bonding, preferably a straight-chain alkylene having 2 to 5 carbon atoms, more preferably a straight-chain alkylene having 3 or 4 carbon atoms, and further preferably a straight-chain alkylene having 4 carbon atoms (-(CH2)4-). The straight-chain alkylene having 4 carbon atoms (-(CH2)4-) is particularly preferably unsubstituted.

[0193] The remaining R not involved in the linking group or single bond A1 ~R A4Preferably, they are each independently hydrogen or an optionally substituted alkyl group, more preferably an optionally substituted alkyl group having 1 to 6 carbon atoms, further preferably an unsubstituted alkyl group having 1 to 6 carbon atoms, and most preferably, they are all methyl groups.

[0194] That is, the partial structure represented by formula (A10) is preferably a structure represented by the following formula (A11).

[0195] [Chemistry 11]

[0196]

[0197] In formula (A11), Me is a methyl group, and the two * positions are connected to X 1 or X 2 One of the two rings bonded is bonded to the other ring at the ** position.

[0198] <Substitution with heavy stable isotopes>

[0199] Each element in the polycyclic aromatic compound represented by formula (1) is an element containing multiple naturally occurring isotopes in a natural abundance ratio unless otherwise specified. Among them, all or part of the elements in each structural formula may contain heavy stable isotopes exceeding the natural abundance ratio (for example, 90 atomic % or more in the case of boron-11 (11B)). In this specification, it is abbreviated as "substituted" as "heavy stable isotope". More specifically, at least one hydrogen can be substituted with deuterium, and at least one nitrogen can be substituted with nitrogen-15 ( 15 N), at least one sulfur may be substituted with sulfur-33 ( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36 S), at least one oxygen may be substituted with oxygen-17 ( 17 O) or oxygen-18 ( 18 O), at least one carbon may be substituted with carbon-13 ( 13 C), at least one boron may be formed from boron-11 ( 11 B) substitution. By replacing at least a portion of the elements with heavy stable isotopes, in particular by replacing at least one boron with boron-11 ( 11 B) substitution can extend the life of an organic electroluminescent device using the polycyclic aromatic compound represented by the formula (1).

[0200] <Substitution using deuterium>

[0201] All or part of the hydrogen in the structure represented by formula (1) may be deuterated. For example, in the compound represented by formula (1), the hydrogen in the ring represented by formula (G), the aryl ring or heteroaryl ring in other A rings, B rings, and C rings, and the substituents thereof may be substituted with deuterium, and among these, the form in which all or part of the hydrogen in the aryl or heteroaryl group is substituted with deuterium can be cited. In addition, from the viewpoint of durability, it is also preferred that all or part of the hydrogen in the compound represented by formula (1) is deuterated.

[0202] <Specific examples of polycyclic aromatic compounds>

[0203] Examples of the polycyclic aromatic compound of the present invention include compounds represented by any of the following structural formulae.

[0204] [Chemistry 12]

[0205]

[0206] [Chemistry 13]

[0207]

[0208] [Chemistry 14]

[0209]

[0210] <Method for producing polycyclic aromatic compounds>

[0211] The polycyclic aromatic compound represented by formula (1) can be produced according to the method described in known documents such as International Publication No. 2015 / 102118.

[0212] Basically, in the case of formula (1), as shown in the following scheme (1), a bonding group (including X 1 or X 2 The ring compound A, the ring compound B and the ring compound C are bonded to produce an intermediate (first reaction), and then the bonding group (Y 1 (e.g. boron atom): containing Y 1 The final product can be produced by bonding the A ring, the B ring and the C ring (the second reaction). In addition, the definitions of the symbols in the structural formula of the following process are the same as those described above. Hal is H, Cl or Br.

[0213] [Chemistry 15]

[0214]

[0215] In the first reaction, for example, in the case of etherification, general reactions such as nucleophilic substitution reaction and Ullmann reaction can be utilized, and in the case of amination, general reactions such as Buchwald-Hartwig reaction, nucleophilic substitution reaction and Goldberg amination can be utilized.

[0216] In the second reaction, a tandem hetero-Friedel-Crafts reaction (a continuous aromatic electrophilic substitution reaction, the same below) can be used. As shown in process (1), the second reaction first uses n-butyl lithium, sec-butyl lithium or tert-butyl lithium to react X 1 With X 2 Hal (Hal is H, Cl or Br) between them is ortho-metallated. Then, boron trichloride or boron tribromide is added to carry out lithium-boron metal exchange, and then a Brünster base such as N,N-diisopropylethylamine (DIPEA) is added to carry out a tandem Bora-Friedel-Crafts reaction, thereby obtaining the target product. In the second reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction.

[0217] When Hal of the intermediate obtained in the first reaction is hydrogen, Y can be directly introduced using BBr3 or BI3 without ortho-metallation. 1 (e.g. a boron atom).

[0218] In the second reaction, as shown in the following process (2), first, n-butyl lithium, sec-butyl lithium or tert-butyl lithium is used to react X 1 With X 2 The Hal (Hal is H, Cl or Br) between the two is ortho-metallated, and the obtained lithiate is reacted with a borate esterification reagent such as 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane to produce a pinacol ester intermediate of boronic acid, and then the obtained borate ester intermediate is reacted with a Lewis acid such as aluminum trichloride to obtain the target product.

[0219] [Chemistry 16]

[0220]

[0221] In process (2), a method using 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborane is shown, but in addition, trimethoxyborane or triisopropoxyborane may be used. In addition, the method described in International Publication No. 2013 / 016185 may be applied and 4,4,5,5-tetramethyl-1,3,2-dioxaborane may be used in the same manner. In addition, in the cyclization reaction of process (2), a Brünster base such as N,N-diisopropylethylamine (DIPEA) may be added to promote the reaction.

[0222] In the above-mentioned processes (1) to (2), the metal is introduced into the desired position by ortho-metallation, but by introducing a halogen such as a bromine atom into the position where the metal is to be introduced, the metal can also be introduced into the desired position by halogen-metal exchange. The above-mentioned method is useful because it can synthesize the target product even when ortho-metallation cannot be performed due to the influence of the substituent.

[0223] In addition, examples of the ortho-metallating reagent used in the above-mentioned processes (1) to (2) include alkyl lithiums such as methyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, isopropyl magnesium chloride, isopropyl magnesium bromide, phenyl magnesium chloride, phenyl magnesium bromide, and a lithium chloride complex of isopropyl magnesium chloride known as Turbo Grignard reagent.

[0224] In addition, as the metallating reagent used in the ortho-metal exchange reaction in the process described so far, in addition to the above reagents, organic base compounds such as lithium diisopropylamide, lithium tetramethylpiperidinide, lithium hexamethyldisilazide, potassium hexamethyldisilazide, lithium chloride tetramethylpiperidinyl magnesium-lithium chloride complex, and tri-n-butyl lithium magnesiumate can also be listed.

[0225] Furthermore, examples of additives that promote the reaction when using alkyl lithium as the metallizing agent include N,N,N',N'-tetramethylethylenediamine, 1,4-diazabicyclo[2.2.2]octane, and N,N-dimethylpropyleneurea.

[0226] Examples of the metal-B (boron) metal exchange reagent used in the above-mentioned processes (1) to (2) include: B trifluoride, B trichloride, B tribromide, B triiodide and other halides of B, CIPN(NEt2)2 and other amide halides of B, B alkoxides, B aryloxides and the like.

[0227] Examples of the Brunst base used in the above-mentioned processes (1) to (2) include: 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, Ar4BNa, Ar4BK, Ar3B, Ar4Si (in addition, Ar is an aromatic group such as phenyl), etc.

[0228] Examples of the Lewis acid used in the above-mentioned processes (1) to (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, CoBr3, etc. In addition, substances obtained by supporting these Lewis acids on solids can also be used in the same manner.

[0229] In the above-described processes (1) to (2), in order to promote the tandem hetero Friedel-Crafts reaction, a Brünster base or a Lewis acid may also be used. Among them, when a halide of B such as trifluoride, trichloride, tribromide, or triiodide is used, as the aromatic electrophilic substitution reaction proceeds, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, or hydrogen iodide are generated, so it is effective to use a Brünster base that captures the acid. On the other hand, when an amination halide of B or an alkoxylate of B is used, as the aromatic electrophilic substitution reaction proceeds, amines and alcohols are generated, so in most cases, there is no need to use a Brünster base, but since the detachment ability of the amino group or the alkoxy group is low, it is effective to use a Lewis acid that promotes the detachment thereof.

[0230] In addition, the polycyclic aromatic compounds of the present invention also include compounds in which at least a portion of the hydrogen atoms are substituted by halogen such as cyano, fluorine or chlorine, or deuterium. Such compounds can be synthesized in the same manner as described above by using raw materials that are halogenated or deuterated by cyanation, fluorination or chlorination at the desired position.

[0231] 2. Organic devices

[0232] The polycyclic aromatic compound of the present invention can be used as a material for organic devices. Examples of organic devices include organic electroluminescent elements, 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 any one or more organic layers in an organic electroluminescent element.

[0233] <2-1. Organic electroluminescent element>

[0234] 2-1-1. Structure of organic electroluminescent element

[0235] Figure 1 This is a schematic cross-sectional view showing an example of an organic EL element.

[0236] Figure 1 The organic EL element 100 shown includes: a substrate 101, an anode 102 arranged on the substrate 101, a hole injection layer 103 arranged on the anode 102, a hole transport layer 104 arranged on the hole injection layer 103, a light-emitting layer 105 arranged on the hole transport layer 104, an electron transport layer 106 arranged on the light-emitting layer 105, an electron injection layer 107 arranged on the electron transport layer 106, and a cathode 108 arranged on the electron injection layer 107.

[0237] In addition, the organic EL element 100 can also reverse the production order to form a structure such as the following, which includes: a substrate 101, a cathode 108 disposed on the substrate 101, an electron injection layer 107 disposed on the cathode 108, an electron transport layer 106 disposed on the electron injection layer 107, a light-emitting layer 105 disposed on the electron transport layer 106, a hole transport layer 104 disposed on the light-emitting layer 105, a hole injection layer 103 disposed on the hole transport layer 104, and an anode 102 disposed on the hole injection layer 103.

[0238] The above-mentioned layers are not all indispensable layers, and the minimum structural unit is set to a structure including an anode 102, a light-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 can be set arbitrarily. In addition, the above-mentioned layers may each include a single layer or a plurality of layers.

[0239] The morphology of the layers constituting the organic EL element may be, in addition to the structural morphology of “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / luminescent layer / electron transport layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”, “substrate / anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / cathode”. The structural morphology of the 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 injection 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", and "substrate / anode / light-emitting layer / electron injection layer / cathode".

[0240] The organic EL element may further have any one or both selected from an electron blocking layer (electron blocking layer) and a hole blocking layer (hole blocking layer). The electron blocking layer has a LUMO that is shallower than the light-emitting layer and a HOMO that is close to the light-emitting layer or the hole transport layer, and is arranged between the light-emitting layer and the hole transport layer. Since the electrons are retained in the light-emitting layer and do not leak out to the hole transport layer, the shortening of the life caused by the degradation of the hole transport layer and the reduction in efficiency caused by the reduction in recombination efficiency can be prevented. The hole blocking layer has a HOMO that is deeper than the light-emitting layer and a LUMO that is close to the light-emitting layer or the hole transport layer, and is arranged between the light-emitting layer and the electron transport layer. Since the holes are retained in the light-emitting layer and do not leak out to the electron transport layer, the shortening of the life caused by the degradation of the electron transport layer and the reduction in efficiency caused by the reduction in recombination efficiency can be prevented. The hole injection / transport layer may also serve as an electron blocking layer. The electron injection / transport layer may also serve as a hole blocking layer.

[0241] The organic EL element may further have a high T1 layer. The high T1 layer has a higher T1 than the main compound, auxiliary dopant compound or emission dopant compound used in the light-emitting layer, and is arranged between the light-emitting layer and the hole transport layer and / or between the light-emitting layer and the electron blocking layer. The value of T1 energy varies depending on the light-emitting mechanism of the element, but has a higher T1 than the compound used in the main body. By having a high T1 layer around the light-emitting layer, triplet energy can be enclosed, and the triplet energy that is usually unrelated to light emission in the fluorescent molecules can be converted into singlet energy, thereby obtaining high efficiency. The hole injection / transport layer or the electron blocking layer can also serve as the high T1 layer. The electron injection / transport layer or the hole blocking layer can also serve as the high T1 layer.

[0242] The polycyclic aromatic compound of the present invention is preferably used as a material for forming an electron transport layer or a material for forming a hole blocking layer, and is more preferably used as a material for forming an electron transport layer.

[0243] 2-1-2. Substrate in organic electroluminescent element

[0244] The substrate 101 is a support of the organic EL element 100, and quartz, glass, metal, plastic, etc. can be generally used. The substrate 101 is formed into a plate, film or sheet according to the purpose, for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, etc. can be used. Among them, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, polysulfone, etc. are preferably used. If it is a glass substrate, soda-lime glass or alkali-free glass, etc. can be used. In addition, the thickness can be sufficient to maintain the mechanical strength. In addition, in order to improve the gas barrier property, a gas barrier film such as a fine silicon oxide film can also be provided on at least one side of the substrate 101. When a plate, film or sheet made of a synthetic resin with low gas barrier property is used as the substrate 101, it is particularly preferred to provide a gas barrier film.

[0245] 2-1-3. Anode in organic electroluminescent element

[0246] The anode 102 plays a role of injecting 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 through these layers.

[0247] As materials for forming the anode 102, inorganic compounds and organic compounds can be cited. As inorganic compounds, for example, metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (Indium Tin Oxide, ITO), indium-zinc oxide (Indium Zinc Oxide, IZO), etc.), metal halides (copper iodide, etc.), copper sulfide, carbon black, ITO glass or Nesa glass, etc. As organic compounds, for example, polythiophenes such as poly(3-methylthiophene), conductive polymers such as polypyrrole and polyaniline, etc. can be cited. In addition, it can be appropriately selected from the substances used as the anode of the organic EL element for use.

[0248] 2-1-4. Hole injection layer and hole transport layer in organic electroluminescent element

[0249] The hole injection layer 103 plays a role of efficiently injecting holes migrated from the anode 102 into the light-emitting layer 105 or the hole transport layer 104. The hole transport layer 104 plays a role of efficiently transporting 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 formed by stacking or mixing one or more hole injection / transport materials. In addition, an inorganic salt such as iron (III) chloride can be added to the hole injection / transport material to form a layer.

[0250] As a hole injection / transport material, it is necessary to efficiently inject / transmit holes from the positive electrode between electrodes to which an electric field is applied, and it is ideal that the hole injection efficiency is high and the injected holes are efficiently transmitted. Therefore, it is preferred that the material has a small ionization potential, a large hole mobility, and excellent stability, and is not prone to produce impurities that become traps during manufacture and use.

[0251] 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, and known compounds used in hole injection layers and hole transport layers of p-type semiconductors and organic EL elements. 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-carbazole-3-yl)-[1,1'-biphenyl]-4,4'-diamine, N 4 ,N 4 ,N 4 ',N 4'-tetrakis[1,1'-biphenyl]-4-yl-[1,1'-biphenyl]-4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine and other triphenylamine derivatives, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives or thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (for example, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilane, etc. Among polymer systems, polycarbonate or styrene derivatives, polyvinylcarbazole and polysilane having the above monomers on the side chain are preferred, but there is no particular limitation as long as it is a compound that can form a thin film required for the production of a light-emitting element and can inject holes from the anode and then transport holes.

[0252] In addition, it is also known that the conductivity of organic semiconductors is strongly affected by their doping. Such organic semiconductor matrix materials contain compounds with good electron donating properties or compounds with good electron accepting properties. In order to dope electron donating materials, strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are known (for example, refer to the literature "M. Pfeiffer, A. Bayer, T. Fritz, K. Leo (M. Pfeiffer , A. Beyer, T. Fritz, K. Leo), "Applied Physics Letters (Appl. Phys. Lett.)", 73(22), 3202-3204 (1998)" and the reference "J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo (J. Blochwitz, M. Pfeiffer, T. Fritz, K. Leo), "Applied Physics Letters (Appl. Phys. Lett.)", 73(6), 729-731 (1998)"). These so-called holes are generated through the electron migration process of the electron-donating basic material (hole transport material). The conductivity of the basic material varies greatly depending on the number and mobility of the holes. As a host material having hole transport properties, for example, benzidine derivatives (N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine (N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)benzidine, TPD), starburst amine derivatives (4,4',4"-tris(N,N-diphenylamino)triphenylamine (4,4',4"-tris(N,N-diphenylamino)triphenylamine, TDATA), or specific metal phthalocyanines (especially zinc phthalocyanine (ZnPc), etc.) are known (Japanese Patent Publication No. 2005-167175).

[0253] The hole injection layer material and the hole transport layer material can also be used in the hole layer material as the following polymer compound or its polymer cross-linked product, or the following pendant polymer compound or its pendant polymer cross-linked product, wherein the polymer compound is obtained by polymerizing a reactive compound substituted with a reactive substituent in the hole injection layer material and the hole transport layer material as a monomer, and the pendant polymer compound is obtained by reacting a main chain polymer with the reactive compound.

[0254] 2-1-5. Light-emitting layer in organic electroluminescent element

[0255] The light-emitting layer 105 is a layer that emits light by allowing holes injected from the anode 102 to recombine with electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material forming the light-emitting layer 105 may be any compound (luminescent compound) that emits light by being excited by the recombination of holes and electrons, and preferably a compound that can form a stable thin film shape and exhibits strong luminescence (fluorescence) efficiency in a solid state.

[0256] The light-emitting layer may be a single layer or may include multiple layers, either of which is acceptable, and is formed of materials for the light-emitting layer (host material, dopant material). The host material and the dopant material may be one type or a combination of multiple types, either of which is acceptable. The dopant material may be contained in the entire host material or in part of the host material, either of which is acceptable. As a doping method, it can be formed by co-evaporation with the host material, but it can also be pre-mixed with the host material and evaporated simultaneously.

[0257] The amount of the host material used varies depending on the type of the host material, and can be determined by matching the characteristics of the host material. The basis for the amount of the host material used is preferably 50% to 99.999% by mass of the total mass of the material for the light-emitting layer, more preferably 80% to 99.95% by mass, and further preferably 90% to 99.9% by mass. In the case where 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 mass of the hole-transporting host material and the electron-transporting host material added together. The ratio of the amount of the hole-transporting host material to the electron-transporting host material used can be 1:9 to 9:1 in terms of mass ratio, preferably 4:6 to 6:4, and more preferably approximately 1:1.

[0258] The amount of the dopant material used varies depending on the type of the dopant material, and can be determined by matching the characteristics of the dopant material. The basis for the amount of the dopant material used is preferably 0.001% to 50% by mass of the total mass of the material for the light-emitting layer, more preferably 0.05% to 20% by mass, and further preferably 0.1% to 10% by mass. If it is within the above range, it is preferred, for example, in terms of preventing concentration quenching.

[0259] As dopant materials, emission dopants and auxiliary dopants can be used. As auxiliary dopant materials, thermally active delayed fluorescence materials can be preferably used. In an organic electroluminescent element using auxiliary dopant materials, it is preferred that the emission dopant material be used in a low concentration in order to prevent concentration quenching. In terms of the efficiency of the thermally active delayed fluorescence mechanism, it is preferred that the auxiliary dopant material be used in a high concentration. Furthermore, in an organic electroluminescent element using a thermally active delayed fluorescence auxiliary dopant material, it is preferred that the emission dopant material be used in a low concentration compared to the auxiliary dopant material in terms of the efficiency of the thermally active delayed fluorescence mechanism of the auxiliary dopant material.

[0260] When using auxiliary dopant materials, the base usage amounts of the main material, auxiliary dopant material and emission dopant material are 40% to 99% by mass, 59% to 1% by mass and 20% to 0.001% by mass, respectively, relative to 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, respectively.

[0261] <Dopant materials>

[0262] As the dopant material, known compounds can be used, and it can be selected from various materials according to the desired luminescent color. Specifically, for example, phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene, and Condensed ring derivatives such as benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, benzotriazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, imidazole derivatives, thiadiazole derivatives, triazole derivatives, pyrazoline derivatives, stilbene derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives or stilbenebenzene derivatives such as bisstyrylanthracene derivatives (Japanese Patent Laid-Open No. 1-245087), bisstyrylarylene derivatives (Japanese Patent Laid-Open No. 2-247278), diazabenzodiindene derivatives, furan derivatives, benzofuran derivatives, phenylisobenzofuran, dimesitylisobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)isobenzofuran, isobenzofuran derivatives such as phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7- Coumarin derivatives such as piperidinyl coumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7-acetoxycoumarin derivatives, 3-benzothiazolyl coumarin derivatives, 3-benzimidazolyl coumarin derivatives, 3-benzoxazolyl coumarin derivatives, dicyanomethylene pyran derivatives, dicyanomethylene thiopyran derivatives, polymethine derivatives, cyanine derivatives, oxybenzanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein Derivatives, pyrylium derivatives, quinolone derivatives, acridine derivatives, oxazine derivatives, phenyl ether derivatives, quinacridone derivatives, quinazoline derivatives, pyrrolopyridine derivatives, furanopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyrromethene derivatives, purple ring ketone derivatives, pyrrolopyrrole derivatives, squarylium salt derivatives, purple anthrone derivatives, phenazine derivatives, acridone derivatives, deazotflavin derivatives, fluorene derivatives and benzofluorene derivatives, etc.

[0263] As the dopant material, it is also preferable to use a polycyclic aromatic compound containing boron described in International Publication No. 2015 / 102118, International Publication No. 2020 / 162600, paragraphs 0097 to 0269 of Japanese Patent Application Laid-Open No. 2021-077890, and the like.

[0264] As a dopant material, a thermally active delayed phosphor can be used. The so-called "thermally active delayed phosphor" refers to a compound that absorbs thermal energy to undergo reverse intersystem crossing from the lowest excited triplet state to the lowest excited singlet state, and is radiatively deactivated from the lowest excited singlet state, thereby emitting delayed fluorescence.

[0265] In the light-emitting layer, a phosphorescent material may also be used as a dopant. For example, iridium complexes described in Japanese Patent Laid-Open No. 2006-089398, Japanese Patent Laid-Open No. 2006-080419, Japanese Patent Laid-Open No. 2005-298483, Japanese Patent Laid-Open No. 2005-097263, Japanese Patent Laid-Open No. 2004-111379, U.S. Patent Application Publication No. 2019 / 0051845, or Japanese Patent Laid-Open No. 2014-239225, Advanced Materials (26: 7116-7121), Nature Asia Materials (NPG Asia Materials) (13, 53 (2021)), Applied Physics Letters (Applied Physics Letters) (117, 253301 (2020)), Light-Emitting Diode-An Empirical Characteristics Outlook and Its Latest Technology Progress Outlook (Light-Emitting Diode-An The platinum complex described in "Outlook On the Empirical Features and Its Recent Technological Advancements" (Chapter 5).

[0266] <Main material>

[0267] Examples of the host material include condensed ring derivatives of anthracene, pyrene and the like which have been known as light emitters in the past, bistyryl derivatives such as bistyrylanthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, fluorene derivatives, benzofluorene derivatives, N-phenylcarbazole derivatives, and carbazolenitrile derivatives.

[0268] From the viewpoint of promoting rather than inhibiting the generation of TADF in the light-emitting layer, the lowest excited triplet energy level (E T1 ) is higher than the highest E T1 E of dopant or auxiliary dopant T1 Specifically, the E of the main material T1 Preferably, the E of the dopant or auxiliary dopant is T1 It is higher by 0.01 eV or more, more preferably higher by 0.03 eV or more, and even more preferably higher by 0.1 eV or more. T1 It is preferably 2.70 eV or more, more preferably 2.73 eV or more, and further preferably 2.80 eV or more.

[0269] TADF-active compounds can also be used in the host material.

[0270] 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.

[0271] 2-1-6. Electron injection layer and electron transport layer in organic electroluminescent element

[0272] The electron injection layer 107 plays a role of efficiently injecting electrons migrated 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 respectively formed by stacking or mixing one or more electron transport / injection materials, or are formed by a mixture of an electron transport / injection material and a polymer binder.

[0273] The so-called electron injection / transport layer is a layer responsible for injecting electrons from the cathode and then transmitting electrons, and it is desirable that the electron injection efficiency is high and the injected electrons are transmitted efficiently. Therefore, it is preferably a material with large electron affinity, large electron mobility, excellent stability, and impurities that are not easy to produce when manufacturing and using it. However, considering the transmission balance of holes and electrons, in the case of mainly playing the role of efficiently preventing the holes from the anode from being recombined and flowing to the cathode side, even if the electron transmission ability is not so high, it has the effect of improving luminous efficiency equally with the material with high electron transmission ability. Therefore, the electron injection / transport layer in the present embodiment may also include the function of the layer that can efficiently prevent the migration of holes.

[0274] As a material (electron transport material) forming the electron transport layer 106 or the electron injection layer 107, it can be arbitrarily selected from compounds conventionally used as electron transfer compounds in photoconductive materials, electron injection layers of organic EL elements, and known compounds used in electron transport layers. The polycyclic aromatic compound of the present invention can be preferably used as a material for forming an electron transport layer. The polycyclic aromatic compound of the present invention can be used in combination with other materials described below as a material for forming an electron transport layer, and in addition to using an electron transport layer containing the polycyclic aromatic compound of the present invention, an electron injection layer formed of other materials or an additional electron transport layer formed of other materials can also be used. In the case of using an additional electron transport layer, the stacking order of multiple electron transport layers is not particularly limited.

[0275] In addition to the polycyclic aromatic compounds of the present invention, as the material used in the electron transport layer or the electron injection layer, it is preferably selected from at least one of the following compounds: a compound containing an aromatic ring or a heteroaromatic ring containing one or more atoms selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus; a pyrrole derivative and its condensed ring derivative; and a metal complex with electron-accepting nitrogen. Specifically, it can be listed: condensed ring aromatic ring derivatives such as naphthalene and anthracene, styrene aromatic ring derivatives represented by 4,4'-bis(diphenylvinyl)biphenyl, purple ring ketone derivatives, coumarin derivatives, naphthalene dicarboximide derivatives, quinone derivatives such as anthraquinone or diphenoquinone, phosphine oxide derivatives, aryl nitrile derivatives and indole derivatives. As a metal complex with electron-accepting nitrogen, for example, hydroxyl oxazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes and benzoquinoline metal complexes can be listed. These materials can be used alone or mixed with different materials.

[0276] In addition, specific examples of other electron transfer compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perirone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, oxadiazole derivatives (1,3-bis[(4-tert-butylphenyl)1,3,4-oxadiazolyl]phenylene, etc.), thiophene derivatives, triazole derivatives (N-naphthyl-2,5-diphenyl-1,3,4-triazole, etc.), thiadiazole derivatives, metal complexes of 8-hydroxyquinoline derivatives, hydroxyquinoline metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzoazole compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, Biologicals, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9'-spirobifluorene, etc.), imidazopyridine derivatives, borane derivatives, benzimidazole derivatives (tris(N-phenylbenzimidazol-2-yl)benzene, etc.), benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis(2,2':6',2"-terpyridine-4'-yl)benzene, etc.), naphthyridine derivatives (bis(1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenylphosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphine oxide derivatives, bisphenylvinyl derivatives, etc.

[0277] In addition, metal complexes having electron-accepting nitrogen can also be used, examples of which include hydroxyquinoline metal complexes, hydroxyoxazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes.

[0278] The materials can be used alone or in combination with different materials.

[0279] Among the above materials, preferred are borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, aromatic nitrile derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and hydroxyquinoline metal complexes.

[0280] In the case where the polycyclic aromatic compound of the present invention is combined with other materials to form an electron transport layer, the other materials preferably include hydroxyquinoline metal complexes or triazine derivatives. The polycyclic aromatic compound of the present invention can be mixed with hydroxyquinoline metal complexes or triazine derivatives to form an electron transport layer or electron injection layer, and the polycyclic aromatic compound of the present invention and hydroxyquinoline metal complexes or triazine derivatives can be used in adjacent layers. In the case where the polycyclic aromatic compound of the present invention is combined with other materials and used in the same layer, it is preferably combined with hydroxyquinoline metal complexes. The injection of electrons into the light-emitting layer can be further promoted, thereby improving electron transportability.

[0281] [Triazine derivatives]

[0282] The triazine derivative is, for example, a compound represented by the following formula (ETM-10), preferably a compound represented by the following formula (ETM-10-1). Details are described in US Patent Application Publication No. 2011 / 0156013.

[0283] [Chemistry 17]

[0284]

[0285] Ar is independently a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. n is an integer of 1 to 3, and is preferably 2 or 3.

[0286] Specific examples of "aryl" include: phenyl which is a monocyclic aromatic group; (2-, 3-, 4-)biphenyl which is a bicyclic aromatic group; (1-, 2-)naphthyl which is a condensed bicyclic aromatic group; terphenyl (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, p-terphenyl-4-yl); condensed tricyclic aromatic groups include: Acenaphthene-(1-, 3-, 4-, 5-)yl, fluorene-(1-, 2-, 3-, 4-, 9-)yl, phenanthren-(1-, 2-)yl, (1-, 2-, 3-, 4-, 9-)phenanthrenyl; tetraphenyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterphenyl) as a tetracyclic aromatic group; triphenylene-(1-, 2-)yl, pyrene-(1-, 2-, 4-)yl, tetracene-(1-, 2-, 5-)yl as a condensed tetracyclic aromatic group; perylene-(1-, 2-, 3-)yl, pentacene-(1-, 2-, 5-, 6-)yl as a condensed pentacyclic aromatic group, etc.

[0287] Specific examples of the heteroaryl group include furanyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanyl, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, isobenzofuranyl, benzo[b]thienyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenazinyl, phenoxathiol, thianthrenyl, and indolizinyl.

[0288] In addition, the aryl group and the heteroaryl group may be substituted, and may be substituted with, for example, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cyano group, or a halogen group, respectively.

[0289] Specific examples of the triazine derivatives include the following.

[0290] [Chemistry 18]

[0291]

[0292] [Hydroxyquinoline metal complexes]

[0293] Examples of the hydroxyquinoline metal complex include compounds represented by the formula (ETM-13).

[0294] [Chemistry 19]

[0295]

[0296] In formula (ETM-13), R 1 ~R 6 Each independently represents hydrogen or a substituent, M represents Li, Al, Ga, Be or Zn, and n represents an integer of 1 to 3.

[0297] Specific examples of the hydroxyquinoline metal complex include 8-hydroxyquinoline lithium (Liq), tris(8-hydroxyquinoline)aluminum, tris(4-methyl-8-hydroxyquinoline)aluminum, tris(5-methyl-8-hydroxyquinoline)aluminum, tris(3,4-dimethyl-8-hydroxyquinoline)aluminum, tris(4,5-dimethyl-8-hydroxyquinoline)aluminum, tris(4,6-dimethyl-8-hydroxyquinoline)aluminum, bis(2-methyl-8-hydroxyquinoline)(phenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(2-methylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(3-methylphenol)aluminum, and bis(2-methyl-8-hydroxyquinoline)(phenol)aluminum. Aluminum, bis(2-methyl-8-hydroxyquinoline)(4-methylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(2-phenylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(3-phenylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(2,3-dimethylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(2,6-dimethylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(3,4-dimethylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)(3,5-dimethylphenol)aluminum phenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(3,5-di-tert-butylphenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(2,6-diphenylphenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(2,4,6-triphenylphenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(2,4,6-trimethylphenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(2,4,5,6-tetramethylphenol) aluminum, bis(2-methyl-8-hydroxyquinoline)(1-naphthol) aluminum, bis(2-methyl-8-hydroxyquinoline)(2-naphthol) aluminum, bis(2,4-di 8-hydroxyquinoline)(2-phenylphenol)aluminum, bis(2,4-dimethyl-8-hydroxyquinoline)(3-phenylphenol)aluminum, bis(2,4-dimethyl-8-hydroxyquinoline)(4-phenylphenol)aluminum, bis(2,4-dimethyl-8-hydroxyquinoline)(3,5-dimethylphenol)aluminum, bis(2,4-dimethyl-8-hydroxyquinoline)(3,5-di-tert-butylphenol)aluminum, bis(2-methyl-8-hydroxyquinoline)aluminum-μ-oxo-bis(2-methyl-8-hydroxyquinoline)aluminum, bis(2,4-dimethyl-8-hydroxyquinoline)aluminum-μ-oxo-bis(2,4-dimethyl-8-hydroxyquinoline) aluminum, bis(2-methyl-4-ethyl-8-hydroxyquinoline) aluminum-μ-oxo-bis(2-methyl-4-ethyl-8-hydroxyquinoline) aluminum, bis(2-methyl-4-methoxy-8-hydroxyquinoline) aluminum-μ-oxo-bis(2-methyl-4-methoxy-8-hydroxyquinoline) aluminum, bis(2-methyl-5-cyano-8-hydroxyquinoline) aluminum-μ-oxo-bis(2-methyl-5-cyano-8-hydroxyquinoline) aluminum, bis(2-methyl-5-trifluoromethyl-8-hydroxyquinoline) aluminum-μ-oxo-bis(2-methyl-5-trifluoromethyl-8-hydroxyquinoline) aluminum, bis(10-hydroxybenzo[h]quinoline) beryllium, etc.

[0298] <Reducing substances>

[0299] The electron transport layer or the electron injection layer may also contain a substance that can reduce the material forming the electron transport layer or the electron injection layer. As long as the reducing substance has a certain reducing property, various substances can be used, 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 preferably used.

[0300] As preferred reducing substances, alkali metals such as Na (work function 2.36eV), K (work function 2.28eV), Rb (work function 2.16eV) or Cs (work function 1.95eV) or alkaline earth metals such as Ca (work function 2.9eV), Sr (work function 2.0eV~2.5eV) or Ba (work function 2.52eV) can be listed, and substances with a work function of 2.9eV or less are particularly preferred. Among these, the more preferred reducing substances are alkali metals of K, Rb or Cs, and more preferably Rb or Cs, and most preferably Cs. The reducing ability of these alkali metals is particularly high. By adding a relatively small amount of the alkali metal to the material forming the electron transport layer or the electron injection layer, the luminous brightness in the organic EL element can be improved or the life can be prolonged. In addition, as the 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 a combination containing Cs is particularly preferred, such as a combination of Cs and Na, Cs and K, Cs and Rb, or Cs and Na and K. By including Cs, the reducing ability can be efficiently exerted, and by adding it to the material forming the electron transport layer or the electron injection layer, the luminance of the light emission in the organic EL element can be improved or the life can be prolonged.

[0301] 2-1-7. Cathode in organic electroluminescent element

[0302] The cathode 108 plays a role of injecting electrons into the light-emitting layer 105 via the electron injection layer 107 and the electron transport layer 106 .

[0303] As the material forming the cathode 108, if it is a substance that can efficiently inject electrons into the organic layer, it is not particularly limited, and the same material as the material forming the anode 102 can be used. Among them, preferably metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium and magnesium or their alloys (magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy such as lithium fluoride / aluminum, etc.) and the like. In order to improve the efficiency of electron injection to improve the characteristics of the element, lithium, sodium, potassium, cesium, calcium, magnesium or alloys containing these low work function metals are effective. However, generally speaking, these low work function metals are unstable in the atmosphere in most cases. In order to improve this point, it is known that there is a method of doping a trace amount of lithium, cesium or magnesium into the organic layer and using an electrode with high stability. As other dopants, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. Among them, it is not limited to these.

[0304] Furthermore, the following are preferred examples: for protecting the electrodes, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys of these metals, inorganic substances such as silicon dioxide, titanium dioxide and silicon nitride, polyvinyl alcohol, vinyl chloride, hydrocarbon polymer compounds, etc. are stacked. The method for making these electrodes is not particularly limited as long as it is a method that can achieve conduction such as resistance heating, electron beam evaporation, sputtering, ion plating and coating.

[0305] 2-1-8. Method for producing organic electroluminescent element

[0306] Each layer constituting the organic EL element can be formed by making the material to constitute each layer into a thin film using a method such as vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular stacking, printing, spin coating, casting, coating, etc. The film thickness of each layer formed in the above manner is not particularly limited and can be appropriately set according to the properties of the material, but is generally in the range of 2nm to 5000nm. The film thickness can generally be measured using a quartz oscillation film thickness measuring device or the like. When using the vapor deposition method for thin film formation, the vapor deposition conditions vary depending on the type of material, the target crystal structure and association structure of the film, etc. The vapor deposition conditions are generally preferably a boat heating temperature of +50°C to +400°C and a vacuum degree of 10 -6 Pa~10 -3 Pa, the vapor deposition rate is 0.01 nm / sec to 50 nm / sec, the substrate temperature is -150°C to +300°C, and the film thickness is appropriately set within the range of 2 nm to 5 μm.

[0307] When a direct current voltage is applied to the organic EL element obtained in the above manner, it can be applied with the anode as + polarity and the cathode as - polarity. If a voltage of about 2V to 40V is applied, light emission can be observed from the transparent or translucent electrode side (anode or cathode, or both). In addition, the organic EL element also emits light when a pulse current or an alternating current is applied. In addition, the waveform of the applied alternating current can be arbitrary.

[0308] Next, as an example of a method for producing an organic EL element, a method for producing an organic EL element including anode / hole injection layer / hole transport layer / light-emitting layer including a host material and a dopant material / electron transport layer / electron injection layer / cathode is described.

[0309] <Evaporation method>

[0310] On a suitable substrate, a thin film of an anode material is formed by a vapor deposition method to make an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. The main material and the dopant material are co-evaporated on the thin film to form a thin film as a light-emitting layer, and an electron transport layer and an electron injection layer are formed on the light-emitting layer, and then a thin film containing a cathode material is formed by a vapor deposition method as a cathode, thereby obtaining a target organic EL element. In addition, in the production of the organic EL element, the production order can also be reversed, and the cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, anode are produced in the order of cathode, electron injection layer, electron transport layer, light-emitting layer, hole transport layer, hole injection layer, anode.

[0311] <Wet film forming method>

[0312] A low molecular weight compound capable of forming each organic layer of an organic EL element is prepared as a liquid organic layer-forming composition, and the composition is used to perform a wet film-forming method. In the absence of an appropriate organic solvent for dissolving the low molecular weight compound, the organic layer-forming composition may be prepared from a high molecular weight compound or the like, wherein the high molecular weight compound is polymerized together with other monomers or main chain polymers having a solubility function as a reactive compound substituted with a reactive substituent in the low molecular weight compound.

[0313] The wet film forming method generally forms a coating film by passing through the following process, wherein the process is a coating process of applying an organic layer forming composition on a substrate and a drying process of removing a solvent from the coated organic layer forming composition. In the case where the polymer compound has a cross-linking substituent (also referred to as a cross-linking polymer compound), the drying process is further cross-linked to form a polymer cross-linked body. Depending on the coating process, the method using a spin coater is called a spin coating method, the method using a slit coater is called a slit coating method, the method using a plate is called a gravure, lithography, reverse lithography, flexographic printing method, the method using an inkjet printer is called an inkjet method, and the method of blowing with a mist is called a spray method. There are methods such as air drying, heating, and reduced pressure drying in the drying process. The drying process can be performed only once, or it can be performed multiple times using different methods or conditions. In addition, for example, different methods can also be used, such as calcination under reduced pressure.

[0314] The wet film forming method refers to a film forming method using a solution, such as a partial printing method (inkjet method), a spin coating method or a casting method, a coating method, etc. The wet film forming method is different from the vacuum evaporation method in that it does not require the use of an expensive vacuum evaporation device and can be formed under atmospheric pressure. In addition, the wet film forming method can be large-scale or continuously produced, thereby reducing manufacturing costs.

[0315] On the other hand, compared with the vacuum evaporation method, the wet film forming method is sometimes difficult to laminate. When using the wet film forming method to make a laminated film, it is necessary to prevent the dissolution of the lower layer caused by the composition of the upper layer, and use a composition with controlled solubility, crosslinking of the lower layer, and an orthogonal solvent (orthogonal solvent, mutually insoluble solvent) etc. However, there are cases where it is difficult to use the wet film forming method for coating all films even if these technologies are used.

[0316] Therefore, a method is generally adopted in which only some layers are formed by a wet film-forming method and the remaining layers are formed by a vacuum deposition method to produce an organic EL element.

[0317] For example, the following shows a part of the procedure for manufacturing an organic EL element by applying the wet film formation method.

[0318] (Procedure 1) Anode film formation by vacuum deposition method

[0319] (Procedure 2) Film formation of a hole injection layer-forming composition containing a hole injection layer material by a wet film formation method

[0320] (Procedure 3) Film formation of a hole transport layer-forming composition containing a hole transport layer material by a wet film formation method

[0321] (Procedure 4) Film formation of a composition for forming a light-emitting layer containing a host material and a dopant material by a wet film formation method

[0322] (Procedure 5) Film formation of electron transport layer by vacuum deposition method

[0323] (Procedure 6) Film formation of electron injection layer by vacuum deposition method

[0324] (Procedure 7) Cathode film formation by vacuum deposition method

[0325] By going through the above process, an organic EL element including anode / hole injection layer / hole transport layer / light-emitting layer including a host material and a dopant material / electron transport layer / electron injection layer / cathode can be obtained.

[0326] Of course, for the electron transport layer and the electron injection layer, a layer-forming composition containing an electron transport layer material and an electron injection layer material can also be used, respectively, to form a film by a wet film-forming method. In this case, it is preferred to use a method of preventing the lower light-emitting layer from dissolving, or a method of forming a film from the cathode side in the opposite manner to the above procedure.

[0327] <Other film forming methods>

[0328] Laser heating drawing method (Laser Induced Thermal Imaging (LITI)) can be used for film formation of the organic layer-forming composition. LITI refers to a method of heating and evaporating a compound attached to a substrate using a laser, and the organic layer-forming composition can be used in the material coated on the substrate.

[0329] <Optional process>

[0330] Before and after each film forming step, appropriate treatment steps, cleaning steps and drying steps may be appropriately added. Examples of treatment steps include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, cleaning treatment using an appropriate solvent and heating treatment. Furthermore, a series of steps for making a bank may be mentioned.

[0331] Photolithography can be used in the production of the bank. As the bank material that can be photolithographically processed, positive resist materials and negative resist materials can be used. In addition, printing methods that can be patterned, such as inkjet printing, gravure lithography, reverse lithography, and screen printing, can also be used. At this time, a permanent resist material can also be used.

[0332] <Organic layer forming composition used in wet film forming method>

[0333] The composition for forming an organic layer is obtained by dissolving a low molecular compound that can form each organic layer of an organic EL element, or a high molecular compound obtained by polymerizing the low molecular compound, in an organic solvent. For example, the composition for forming a luminescent layer contains a polycyclic aromatic compound (or its high molecular compound) as at least one dopant material as a first component, at least one main material as a second component, and at least one organic solvent as a third component. The first component functions as a dopant component of the luminescent layer obtained from the composition, and the second component functions as a main component of the luminescent layer. The third component functions as a solvent that dissolves the first component and the second component in the composition, and provides a smooth and uniform surface shape by using the controlled evaporation rate of the third component itself during coating.

[0334] <Organic solvent>

[0335] The organic layer forming composition comprises at least one organic solvent. By controlling the evaporation rate of the organic solvent during film formation, the film forming property and the presence or absence of defects, surface roughness, and smoothness of the coating film can be controlled and improved. In addition, when using the inkjet method for film formation, the stability of the meniscus at the pinhole of the inkjet head can be controlled, and the ejection property can be controlled / improved. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, the electrical properties, luminescent properties, efficiency, and life of the organic EL element having the organic layer obtained by the organic layer forming composition can be improved.

[0336] The organic solvent is removed from the coating by drying processes such as vacuum, decompression, heating, etc. after film formation. When heating, from the perspective of improving the coating film-forming property, it is preferably carried out below the glass transition temperature (Tg) of at least one of the solutes + 30 ° C. In addition, from the perspective of reducing the residual solvent, it is preferably heated above the glass transition temperature (Tg) of at least one of the solutes -30 ° C. Even if the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is also fully removed because the film is thin. In addition, it can be dried multiple times at different temperatures, and a variety of drying methods can also be used in combination.

[0337] (2) Specific examples of organic solvents

[0338] As the organic solvent used in the composition for forming the organic layer, 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 can be cited, but are not limited thereto. In addition, the solvents can be used alone or in combination.

[0339] <Optional ingredients>

[0340] The composition for forming an organic layer may contain an optional component within a range that does not impair its properties. Examples of the optional component include a binder and a surfactant.

[0341] <Composition and physical properties of the organic layer-forming composition>

[0342] The content of each component in the organic layer forming composition is determined from the viewpoints of good solubility, storage stability and film-forming properties of each component in the organic layer forming composition, high-quality film quality of the coating obtained from the organic layer forming composition, good ejection properties when using an inkjet method, and good electrical properties, luminescent properties, efficiency and life of an organic EL element having an organic layer made using the composition.

[0343] The composition for forming an organic layer can be prepared by appropriately selecting the components and stirring, mixing, heating, cooling, dissolving, dispersing, etc. by known methods. In addition, filtering, degassing (also called degassing), ion exchange treatment, and inert gas replacement / sealing treatment can also be appropriately selected after preparation.

[0344] 2-1-9. Application examples of organic electroluminescent elements

[0345] The present invention can also be applied to a display device including an organic EL element, a lighting device including an organic EL element, or the like.

[0346] A display device or lighting device including an organic EL element can be manufactured by a known method such as connecting the organic EL element of this embodiment to a known driving device, and can be driven using a known driving method such as DC driving, pulse driving, AC driving, etc. as appropriate.

[0347] As display devices, for example, panel displays such as color flat panel displays, flexible displays such as flexible color organic electroluminescent (EL) displays, etc. (for example, refer to Japanese Patent Laid-Open No. 10-335066, Japanese Patent Laid-Open No. 2003-321546, Japanese Patent Laid-Open No. 2004-281086, etc.). In addition, as display modes of displays, for example, matrix modes and segment modes can be listed. In addition, matrix display and segment display can coexist in the same panel.

[0348] In a matrix, pixels for display are arranged two-dimensionally in a grid or mosaic shape, etc., so that text or images are displayed by a collection of pixels. The shape or size of a pixel is determined according to the purpose. For example, in the image and text display of personal computers, monitors, and televisions, quadrilateral pixels with a side of less than 300 μm are usually used. In addition, in the case of large displays such as display screens, pixels with a side of mm are used. In the case of monochrome display, it is sufficient to arrange pixels of the same color. In the case of color display, red, green, and blue pixels are displayed in parallel. In the case, typical ones are triangular and stripe types. Moreover, as a driving method of the matrix, it can be either a line-sequential driving method or an active matrix. Line-sequential driving has the advantage of simple structure, but in the case of considering the operating characteristics, active matrix is ​​sometimes more excellent, so the driving method also needs to be used according to the purpose.

[0349] In the segmented method (type), a pattern is formed in a manner to display predetermined information, and the determined area is illuminated. Examples include: time or temperature display in a digital clock or thermometer, operating status display of audio equipment or induction cookers, and panel display of a car.

[0350] As lighting devices, for example, lighting devices such as indoor lighting, backlight sources of liquid crystal display devices, etc. can be listed (for example, refer to Japanese Patent Publication No. 2003-257621, Japanese Patent Publication No. 2003-277741, Japanese Patent Publication No. 2004-119211, etc.). Backlight sources are mainly used to improve the visibility of display devices that do not emit light by themselves, and are used for liquid crystal display devices, clocks, audio devices, automobile panels, display boards, and logos. In particular, as a backlight source for personal computers where thinning is becoming a problem in liquid crystal display devices, if it is considered that the existing methods are difficult to be thinned due to the inclusion of fluorescent lamps or light guide plates, the backlight source using the light-emitting element of this embodiment has the characteristics of being thin and lightweight.

[0351] <2-2. Other organic devices>

[0352] The polycyclic aromatic compound of the present invention can be used not only in the organic electroluminescent element, but also in the preparation of organic field effect transistors or organic thin film solar cells.

[0353] An organic field effect transistor is a transistor that uses an electric field generated by voltage input to control current. In addition to a source electrode and a drain electrode, a gate electrode is also provided. An organic field effect transistor is a transistor in which an electric field is generated when a voltage is applied to the gate electrode, and the flow of electrons (or holes) flowing between the source electrode and the drain electrode can be arbitrarily blocked to control the current. Compared with a single transistor (bipolar transistor), a field effect transistor is easy to miniaturize and is often used as a component constituting an integrated circuit, etc.

[0354] Regarding the structure of an organic field effect transistor, generally, a source electrode and a drain electrode are provided in contact with an organic semiconductor active layer formed using the polycyclic aromatic compound of the present invention, and a gate electrode is provided via an insulating layer (dielectric layer) in contact with the organic semiconductor active layer. As an example of its element structure, the following structure can be cited.

[0355] (1) Substrate / gate electrode / insulator layer / source electrode, drain electrode / organic semiconductor active layer

[0356] (2) Substrate / gate electrode / insulator layer / organic semiconductor active layer / source electrode, drain electrode

[0357] (3) Substrate / organic semiconductor active layer / source electrode, drain electrode / insulator layer / gate electrode

[0358] (4) Substrate / source electrode, drain electrode / organic semiconductor active layer / insulator layer / gate electrode

[0359] The organic field effect transistor configured in this way can be used as a pixel driving switch element of an active matrix driving liquid crystal display or an organic electroluminescent display, etc.

[0360] Organic thin film solar cells have a structure in which an anode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a cathode of ITO or the like are stacked 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 compounds of the present invention can be used as materials for hole transport layers, p-type semiconductor layers, n-type semiconductor layers, and electron transport layers according to their physical properties. In organic thin film solar cells, the polycyclic aromatic compounds of the present invention can function as hole transport materials or electron transport materials. In addition to the above layers, organic thin film solar cells may also appropriately include a hole blocking layer, an electron blocking layer, an electron injection layer, a hole injection layer, a smoothing layer, and the like. In organic thin film solar cells, known materials used for organic thin film solar cells can be appropriately selected for use in combination.

[0361] <3. Wavelength conversion materials>

[0362] Currently, the application of multicolor technology based on color conversion to liquid crystal displays or organic EL displays, lighting, etc. is being actively studied. The so-called color conversion is to convert the light emitted from the light source into light with a longer wavelength, for example, it means converting ultraviolet light or blue light into green light or red light. The wavelength conversion material with the color conversion function is filmed, for example, combined with a blue light source, so that the three primary colors of blue, green and red can be extracted from the blue light source, that is, white light can be extracted. This white light source composed of a combination of a blue light source and a wavelength conversion film with a color conversion function is used as a light source unit, and combined with a liquid crystal drive part and a color filter, so that a full-color display can be made. In addition, if there is no liquid crystal drive part, it can be directly used as a white light source, for example, it can be used as a white light source for light-emitting diode (LED) lighting, etc. In addition, a blue organic EL element is used as a light source and combined with a wavelength conversion film that converts blue light into green light and red light, so that a full-color organic EL display without using a metal mask can be made. Furthermore, by using a blue micro LED as a light source and combining it with a wavelength conversion film that converts blue light into green light and red light, a low-cost full-color micro LED display can be produced.

[0363] The polycyclic aromatic compound of the present invention can be used as the wavelength conversion material. The wavelength conversion material containing the polycyclic aromatic compound of the present invention can be used to convert ultraviolet light or light from a light source or light-emitting element that generates blue light with a shorter wavelength into blue light or green light with high color purity suitable for use in a display device (a display device or a liquid crystal display device using an organic EL element). The adjustment of the converted color can be carried out by appropriately selecting the substituent of the polycyclic aromatic compound of the present invention, the binder resin used in the wavelength conversion composition described later, etc. The wavelength conversion material is prepared as a wavelength conversion composition containing the polycyclic aromatic compound of the present invention. In addition, the wavelength conversion composition can also be used to form a wavelength conversion film.

[0364] The wavelength conversion composition may contain a binder resin, other additives, and a solvent in addition to the polycyclic aromatic compound of the present invention. As the binder resin, for example, the resins described in paragraphs 0173 to 0176 of International Publication No. 2016 / 190283 may be used. As other additives, the compounds described in paragraphs 0177 to 0181 of International Publication No. 2016 / 190283 may be used. As the solvent, the description of the solvent contained in the light-emitting layer forming composition may be referred to.

[0365] The wavelength conversion film includes a wavelength conversion layer formed by curing the wavelength conversion composition. As a method for making a wavelength conversion layer from a wavelength conversion composition, reference can be made to a known film formation method. The wavelength conversion film may include only a wavelength conversion layer formed by a composition comprising a polycyclic aromatic compound of the present invention, or may include other wavelength conversion layers (for example, a wavelength conversion layer that converts blue light into green light or red light, a wavelength conversion layer that converts blue light or green light into red light). Furthermore, the wavelength conversion film may also include a substrate layer, or a barrier layer for preventing the color conversion layer from deteriorating due to oxygen, moisture, or heat.

[0366] [Example]

[0367] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0368] <Synthesis of Compounds>

[0369] Synthesis example(1)

[0370] Synthesis of compound (1a-1)

[0371] [Chemistry 20]

[0372]

[0373] Under nitrogen atmosphere, 3-(2-bromo-3-fluorophenoxy)-1,1'-biphenyl (29.2 g), 9,9'-spirobi[fluorene]-2-ol (24.9 g), potassium carbonate (23.5 g) and N-methylpyrrolidone (NMP) (145 ml) were placed in a flask, stirred at 175°C for 27 hours, and then water was added to stop the reaction. Toluene was added for separation, and then purified by silica gel chromatography (eluent: toluene), and concentrated to obtain 2-(3-([1,1'-biphenyl]-3-yloxy)-2-bromophenoxy)-9,9'-spirobi[fluorene] (34 g).

[0374] [Chemistry 21]

[0375]

[0376] Under a nitrogen atmosphere, 2-(3-([1,1'-biphenyl]-3-yloxy)-2-bromophenoxy)-9,9'-spirobi[fluorene] (27 g) and xylene (270 ml) were placed in a flask, cooled to -5°C, and then a 2.70 M n-butyllithium hexane solution (15.7 ml) was added dropwise. After the addition was completed, the mixture was stirred for 10 minutes, cooled to -60°C, and then boron tribromide was added dropwise. After the temperature was raised to -6°C, N,N-diisopropylethylamine (DIPEA) (13.0 g) was added, and the mixture was stirred for 5 hours under heating and reflux. After the heating was completed, the reaction solution was cooled in an ice bath, and an aqueous sodium acetate solution (100 ml) was added dropwise. Then, heptane (160 ml) was added and the precipitated solid was separated by filtration. After dissolving it in chlorobenzene, it was purified by silica gel chromatography (eluent: chlorobenzene) to obtain a crude product of compound (1a-1). The product was recrystallized from ethyl acetate and then purified by sublimation to obtain compound (1a-1) (6.3 g).

[0377] [Chemistry 22]

[0378]

[0379] The structure of the compound was confirmed by mass spectrometry (MS) and nuclear magnetic resonance (NMR) measurements.

[0380] <Compound (1a-1)>

[0381] 1 H-NMR (CDCl3): δ = 9.11 (s, 1H), 8.92 (d, 1H), 8.08 (d, 1H), 7.89 (d, 2H), 7.79-7.81 (m, 3H), 7.74 (d, 1H), 7.70 (d, 1H) ), 7.54(t,2H), 7.45(td,2H), 7.40(t,2H), 7.20(d,1H), 7.10~7.18(m,3H), 7.02(d,1H), 6.93(s,1H), 6.81(t,3H).

[0382] Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) + )=584.19

[0383] Synthesis example (2):

[0384] Synthesis of compound (1a-2)

[0385] [Chemistry 23]

[0386]

[0387] The synthesis was carried out by the same method as in Synthesis Example (1).

[0388] 1 H-NMR (CDCl3): δ = 9.10 (s, 1H), 8.88 (dd, 1H), 8.07 (d, 1H), 7.88 (d, 2H), 7.76 (td, 1H), 7.71 (t, 1H), 7.57 (d, 1H), 7.49(td,1H), 7.45(t,1H), 7.39(td,2H), 7.19(d,1H), 7.05~7.16(m,3H), 7.02(d,1H), 6.92(s,1H), 6.80(t,3H).

[0389] MALDI-TOF-MS (M + )=508.16

[0390] Synthesis example (3):

[0391] Synthesis of Compound (1a-6)

[0392] [Chemistry 24]

[0393]

[0394] The synthesis was carried out by the same method as in Synthesis Example (1). MALDI-TOF-MS (M + )=524.16

[0395] Synthesis example (4):

[0396] Synthesis of Compound (1a-13)

[0397] [Chemistry 25]

[0398]

[0399] The synthesis was carried out by the same method as in Synthesis Example (1). MALDI-TOF-MS (M + )=510.18

[0400] Synthesis example (5):

[0401] Synthesis of Compound (1a-18)

[0402] [Chemistry 26]

[0403]

[0404] The synthesis was carried out by the same method as in Synthesis Example (1). MALDI-TOF-MS (M + )=510.18

[0405] Synthesis example (6):

[0406] Synthesis of Compound (1a-20)

[0407] [Chemistry 27]

[0408]

[0409] The synthesis was carried out by the same method as in Synthesis Example (1).

[0410] MALDI-TOF-MS (M + )=540.14

[0411] Synthesis example (7):

[0412] Synthesis of Compound (1a-21)

[0413] [Chemistry 28]

[0414]

[0415] The synthesis was carried out by the same method as in Synthesis Example (1).

[0416] MALDI-TOF-MS (M + )=508.16

[0417] <Fabrication and evaluation of organic EL elements>

[0418] Next, the preparation and evaluation of an organic EL device using the compound of the present invention are described. However, the application of the compound of the present invention is not limited to the examples shown below, and the film thickness or constituent material of each layer can be appropriately changed according to the basic physical properties of the compound of the present invention.

[0419] [Production of organic EL elements]

[0420] The material composition of each layer in the organic EL devices of Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-8 and EL characteristic data are shown in Tables 1 and 2. The electron transport layer 2 was formed by co-evaporation of the compound described in the table and Liq in a mass ratio of 1 / 1.

[0421] [Table 1]

[0422]

[0423] [Table 2]

[0424]

[0425] The chemical structures of "HI", "IL", "HT-1", "HT-2", "BH-1", "BD-1", "ET-1", "ET-2", "Liq", comparative compound (1), comparative compound (2), comparative compound (3), and comparative compound (4) in the above-mentioned tables are shown below.

[0426] [Chemistry 29]

[0427]

[0428] [Chemistry 30]

[0429]

[0430] Comparative compounds (1) and (2) were synthesized according to the method described in the specification of Chinese Patent Application Publication No. 113773339. Comparative compounds (3) and (4) were synthesized from intermediates (A-11) and (A-22) and intermediates (A-1) and (A-23), respectively, in the same manner as in Synthesis Example (1).

[0431] [Chemistry 31]

[0432]

[0433] [Chemistry 32]

[0434]

[0435] (Example 1-1)

[0436] A glass substrate of 26 mm×28 mm×0.7 mm (manufactured by Nippon Electric Glass Co., Ltd.) on which a 120 nm thick ITO film was formed by sputtering was used as a transparent supporting substrate. The transparent supporting substrate was fixed on a substrate holder of a commercially available vapor deposition apparatus (manufactured by Choshu Industry Co., Ltd.), and a molybdenum vapor deposition boat containing HI, IL, HT-1, HT-2, BH-1, BD-1, compound (1a-1), ET-2 and Liq, and an aluminum nitride vapor deposition boat containing Mg and Ag, respectively, were installed.

[0437] The following layers were formed in order on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 5×10 -4Pa, first, HI is heated and evaporated in a manner to make the film thickness 40nm, then IL is heated and evaporated in a manner to make the film thickness 5nm, then HT-1 is heated and evaporated in a manner to make the film thickness 45nm, then HT-2 is heated and evaporated in a manner to make the film thickness 10nm, to form a hole layer comprising four layers. Next, BH-1 and BD-1 are heated at the same time and evaporated in a manner to make the film thickness 25nm to form a light-emitting layer. The evaporation rate is adjusted in a manner such that the mass ratio of BH-1 to BD-1 is about 98 to 2. Then, compound (1a-1) is heated and evaporated in a manner to make the film thickness 5nm to form an electron transport layer 1. Furthermore, ET-2 and Liq are heated at the same time and evaporated in a manner to make the film thickness 25nm to form an electron transport layer 2. The evaporation rate is adjusted in a manner such that the mass ratio of ET-2 to Liq is about 50 to 50. The deposition rate of each layer is 0.01nm / sec to 1nm / sec. Thereafter, Liq is heated and vapor-deposited at a deposition rate of 0.01nm / sec to 0.1nm / sec so that the film thickness becomes 1nm, and then magnesium and silver are heated at the same time and vapor-deposited so that the film thickness becomes 100nm to form a cathode, thereby obtaining an organic EL element. At this time, the deposition rate is adjusted between 0.1nm / sec and 10nm / sec so that the atomic ratio of magnesium to silver becomes 10 to 1.

[0438] (Example 1-2 to Example 1-14, Comparative Example 1-1 to Comparative Example 1-8)

[0439] Organic EL devices of Examples 1-2 to 1-14 and Comparative Examples 1-1 to 1-8 were obtained by the method according to Example 1-1 except that the materials of the electron transport layer 1 and the electron transport layer 2 were replaced with the materials described in the above tables.

[0440] [Evaluation of vapor deposition type organic EL device]

[0441] The quantum efficiency of a light-emitting element includes internal quantum efficiency and external quantum efficiency. The internal quantum efficiency indicates the proportion of external energy injected into the light-emitting layer of the light-emitting element as electrons (or holes) that is purely converted into photons. On the other hand, the external quantum efficiency is calculated based on the amount of photons released to the outside of the light-emitting element. A portion of the photons generated in the light-emitting layer are absorbed by the inside of the light-emitting element or continuously reflected without being released to the outside of the light-emitting element, so the external quantum efficiency is lower than the internal quantum efficiency.

[0442] The external quantum efficiency was measured as follows: Using a voltage / current generator R6144 manufactured by Advantest, a current was applied so that the device brightness reached 10 mA / cm 2 The element emits light by applying a voltage of . Using a spectroradiometer SR-3AR manufactured by TOPCON, the spectral radiance brightness in the visible light region is measured from a direction perpendicular to the light-emitting surface. Assuming that the light-emitting surface is a completely diffuse surface, the value of the spectral radiance brightness of each wavelength component measured is divided by the wavelength energy and multiplied by π to obtain the number of photons at each wavelength. Then, the number of photons is accumulated in the observed full wavelength region and set as the total number of photons released from the element. The value obtained by dividing the applied current value by the elementary charge is set as the number of carriers injected into the element, and the value obtained by dividing the total number of photons released from the element by the number of carriers injected into the element is the external quantum efficiency.

[0443] The organic EL elements of Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-8 were prepared, and the EL characteristics were measured by applying a direct current voltage with an ITO electrode as an anode and a magnesium / silver electrode as a cathode. 2 The characteristic driving voltage (V) and external quantum efficiency (%) of the light emission were then measured at 20 mA / cm 2 The results are shown in Tables 3 and 4.

[0444] [Table 3]

[0445]

[0446] [Table 4]

[0447]

[0448] As mentioned above, a part of the compounds of the present invention have been evaluated as materials for organic EL devices and shown to be excellent materials, but other compounds that have not been evaluated also have the same basic skeleton and are compounds with similar structures as a whole, and those skilled in the art can understand that they are also excellent materials for organic EL devices.

[0449] [Industrial Applicability]

[0450] According to a preferred embodiment of the present invention, an organic EL element is produced by using an electron transport material containing a polycyclic aromatic compound represented by formula (1), so that an organic EL element having excellent driving voltage and luminous efficiency can be provided.

Claims

1. A polycyclic aromatic compound represented by formula (1); [Chemistry 1] In formula (1), Ring A, Ring B and Ring C are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, wherein, At least one of the rings A, B and C is a ring represented by formula (G); Y 1 For >B-, >P-, >P(=O)-, >P(=S)-, >Al-, >Ga-, >As-, >Si(-R IY )-, or>Ge(-R GY )-, R IY and R GY are each independently a substituted or unsubstituted aryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted alkyl, or a substituted or unsubstituted cycloalkyl; X 1 and X 2 Each independently is >NR NX 、>O、>S、>C(-R CX )2、>Si(-R IX )2, or>Se, R NX , 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, and the two R CX Bonded to each other to form a ring, two R IX Bonded to each other to form a ring, R NX , R CX and R IX Each independently bonds to at least one of the A ring, the B ring, and the C ring via a linking group or a single bond; In formula (G), Any two or three consecutive Z g For Y 1 and X 1 and X 2 or X 1 or X 2 Bonded carbon, Other Z g are independently -N= or -C(-R g )=,R g are independently hydrogen or a substituent, Two adjacent R g bonded to each other and to the carbon atoms to which they are bonded to form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring; L 1 Both are hydrogen, or two L 1 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2. >S or >Se, L 2 Both are hydrogen, or two L 2 Bond to each other to form single bonds, >O, >NR NL 、>Si(-R IL )2. >S or >Se, R NL and R IL are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and the two R IL Bonded to each other to form a ring, W is C or Si; In formula (1), at least one hydrogen is replaced by deuterium, and at least one nitrogen is replaced by nitrogen-15( 15 N) substituted, at least one sulfur is replaced by sulfur-33 ( 33 S), sulfur-34 ( 34 S) or sulfur-36( 36 S), at least one oxygen is replaced by oxygen-17 ( 17 O) or oxygen-18 ( 18 O) substituted, at least one carbon is replaced by carbon-13 ( 13 C) substituted, at least one boron is replaced by boron-11 ( 11 B) Replacement.

2. The polycyclic aromatic compound according to claim 1, wherein Y 1 is>B-.

3. The polycyclic aromatic compound according to claim 1, wherein X 1 and X 2 are respectively independently >O, >S or >Se.

4. The polycyclic aromatic compound according to claim 1, wherein Other Z g All are -C(-R g )=, and R g are hydrogen, or Other Z g All are -C(-R g )=, any adjacent set of two R g are bonded to each other and together with the carbon atoms to which they are bonded form a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring, except that R g All are hydrogen.

5. The polycyclic aromatic compound according to any one of claims 1 to 4, wherein Two L 2 They bond to each other to form single bonds, >O or >S.

6. The polycyclic aromatic compound according to any one of claims 1 to 4, wherein Ring B is a ring represented by formula (G).

7. The polycyclic aromatic compound according to claim 6, which is represented by any of the following formulas: [Chemistry 2] 8. The polycyclic aromatic compound according to any one of claims 1 to 4, wherein Ring A is a ring represented by formula (G).

9. The polycyclic aromatic compound according to claim 8, which is represented by the following formula: [Chemistry 3] 10. A material for an organic device, comprising the polycyclic aromatic compound according to any one of claims 1 to 4. 11 . An organic electroluminescent element comprising: a pair of electrodes including 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 claim 1 .

12. The organic electroluminescent element according to claim 11, wherein The organic layer is an electron transport layer.

13. A display device or a lighting device, comprising the organic electroluminescent element according to claim 11.

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