KR20230119604A - Organic Electroluminescent Device - Google Patents

Abstract

The present invention is to provide an organic electroluminescent device having a high external quantum efficiency, the organic electroluminescent device of the present invention, a polycyclic aromatic compound represented by formula (1) as an emitter dopant, a hole-transporting host material, electron It has a light emitting layer containing at least two selected from the group consisting of a transport host material and an assisting dopant (A ring, B ring, D ring, E ring, F ring, and G ring are substituted or unsubstituted aryl rings, etc., Z is -C(-H)=, Y is B, etc., X is >NR ^NX , >O, or >S, etc., R ^NX is substituted or unsubstituted aryl, etc., the structure represented by formula (1) At least one selected from the group consisting of an aryl ring and a heteroaryl ring in may be condensed with at least one cycloalkane, and at least one hydrogen in the structure represented by formula (1) is cyano; may be substituted with halogen or deuterium).

Description

Organic electroluminescent device {Organic Electroluminescent Device}

The present invention relates to an organic electroluminescent device, a display device and a lighting device using the same.

Conventionally, display devices using electroluminescent light emitting elements can be reduced in power and reduced in thickness, so various researches have been conducted, and organic electroluminescent elements made of organic materials have been actively studied because they are easy to reduce in weight and increase in size. In particular, for the development of organic materials having luminescent properties such as blue, which is one of the three primary colors of light, and the development of organic materials equipped with charge transport capabilities (possibly becoming semiconductors or superconductors) such as holes and electrons, polymer compounds , regardless of low molecular weight compounds, have been actively studied so far.

An organic electroluminescent element has a structure composed of a pair of electrodes composed of an anode and a cathode, and one layer or a plurality of layers disposed between the pair of electrodes and containing an organic compound. Layers containing organic compounds include a light emitting layer and a charge transport/injection layer that transports or injects charges such as holes and electrons, and various organic materials suitable for these layers have been developed.

Patent Literature 1 discloses that a polycyclic aromatic compound containing boron is useful as a material for an organic electroluminescent device or the like. In Patent Literature 1, a new structure for dramatically improving the color purity of a TADF material, which is generally considered to have high luminous efficiency but low color purity, is proposed.

As a host material for TADF materials, use of a combination of an electron-transporting host material and a hole-transporting host material has been studied (Non-Patent Documents 1 to 3).

International Publication No. 2015/102118

Advanced Functional Materials, 24, 2014, 3970 Advanced Materials, 26, 2014, 5684 Synthetic Metals, 201, 2015, 49

As described above, although various materials have been developed as materials used for organic EL devices, development of materials composed of compounds different from conventional ones is expected in order to increase the choice of materials for organic EL devices. An object of the present invention is to provide an organic EL device using a novel material combination. An object of the present invention is to provide an organic EL device having high external quantum efficiency.

In order to solve the above problem, the inventors of the present invention intensively examine and use a plurality of host materials and assisting dopants together with a polyaromatic compound in which a plurality of aromatic rings are condensed to form a light emitting layer, thereby obtaining an excellent organic EL element. found, and completed the present invention. That is, the present invention provides the following organic electroluminescent device.

<1> An organic electroluminescent device having a pair of electrodes composed of an anode and a cathode, and a light emitting layer disposed between the pair of electrodes,

The light emitting layer includes at least two selected from the group consisting of an emitting dopant, a hole transporting host material, an electron transporting host material, and an assisting dopant,

The polycyclic aromatic compound represented by formula (1), a polymer compound obtained by polymerizing the polycyclic aromatic compound as a monomer, a polymer crosslinked product obtained by further crosslinking the polymer compound, and the polycyclic aromatic compound having a main chain shape An organic electroluminescent device comprising at least one selected from the group consisting of a pendant-type polymer compound reacted with a polymer and a pendant-type polymer crosslinked product obtained by further crosslinking the pendant-type polymer compound;

In formula (1),

A ring, B ring, D ring, E ring, F ring, and G ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,

Z is -C(-R ^Z )= or -N=;

R ^Z is each independently hydrogen or a substituent,

Y is each independently B, P, P=O, or P=S;

X is each independently >NR ^NX , >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S, or >Se, and R ^NX is hydrogen, substituted or unsubstituted aryl , substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^CX and R ^IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted hetero Aryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, two R ^CX may be bonded to each other to form a ring, and two R ^IX may be bonded to each other to form a ring, R ^NX , R ^CX , and R ^IX may each be bonded to one or two rings to which X containing itself bonds through a single bond or a linking group;

At least one selected from the group consisting of an aryl ring and a heteroaryl ring in the structure represented by formula (1) may be condensed with at least one cycloalkane, and the cycloalkane is substituted with at least one substituent may be present, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;

An organic electroluminescent element in which at least one hydrogen in the structure represented by formula (1) may be substituted with cyano, halogen, or deuterium.

<2> The organic electroluminescent element according to <1>, in which formula (1) is represented by formula (1B);

In formula (1B),

Y and X have the same meaning as Y and X in formula (1),

Z has the same meaning as Z in formula (1), provided that when Z in Z = Z is -C (-R ^Z ) =, two R ^Z are bonded to each other to form an aryl ring or a heteroaryl ring The aryl ring or heteroaryl ring formed may each have a substituent, and each of Z=Z is independently >NR, >O, >C(-R) ₂ , >Si(-R) ₂ , It may be >S or >Se, and R in >NR, >C(-R) ₂ , and >Si(-R) ₂ is each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted of heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, wherein the >C(-R) ₂ and the >Si(-R) ₂ of 2 R are bonded to each other to form a ring, may be,

In the structure represented by formula (1B), at least one of the aryl ring or heteroaryl ring may be condensed with at least one cycloalkane, and the cycloalkane may be substituted with at least one substituent. At least one -CH ₂ - in the alkane may be substituted with -O-;

At least one hydrogen in the structure represented by formula (1B) may be substituted with cyano, halogen or deuterium.

<3> The organic electroluminescent device according to <2>, wherein all of Z are -C(-R ^Z )=.

<4> R ^Z is each independently hydrogen, alkyl, phenyl which may be substituted with alkyl, diphenylamino which may be substituted with alkyl, or carbazolyl which may be substituted with alkyl, <2> or <3 The organic electroluminescent device described in >.

<5> The organic electroluminescent device according to any one of <1> to <4>, wherein X is >O, >NR ^NX , or >S.

<6> The organic electroluminescent device according to <1>, wherein the polyaromatic compound represented by formula (1) is represented by any of the following formulas;

In the formula, Me is methyl and tBu is t-butyl.

<7> The organic electroluminescent device according to any one of <1> to <6>, wherein the emitting dopant contains a polyaromatic compound represented by formula (1).

<8> The emitting dopant is a polymer compound obtained by polymerizing the polycyclic aromatic compound represented by formula (1) as a monomer, a polymer crosslinked product obtained by further crosslinking the polymer compound, and a polymer compound obtained by further crosslinking the polycyclic aromatic compound with a main chain polymer. The organic electroluminescent device according to any one of <1> to <6>, comprising at least one member selected from the group consisting of a pendant polymer compound reacted with and a pendant polymer crosslinked product obtained by further crosslinking the pendant polymer compound. .

<9> The organic electroluminescent device according to any one of <1> to <8>, wherein the light-emitting layer contains both the hole-transporting host material and the electron-transporting host material.

<10> The hole-transporting host material is represented by formula (HH-1) or has a partial structure represented by formula (HH-1) and has at least three selected from the group consisting of aryl rings and heteroaryl rings A compound having a structure containing a ring,

The electron-transporting host material has a partial structure represented by any one of formulas (EH-1A) to (EH-1D), or any of formulas (EH-1A) to (EH-1D), and an aryl ring And a compound having a structure containing at least three rings selected from the group consisting of heteroaryl rings, or a polyaromatic compound represented by formula (EH-1b), or having a plurality of structures represented by formula (EH-1b) below. an organic electroluminescent device according to any one of <1> to <9>, which is a polyaromatic compound;

In formula (HH-1),

Q is >O, >S, or >NA ^H ;

One carbon atom next to the carbon atom to which Q is bonded in each of the two phenyls in the formula (HH-1) may be bonded to each other by L,

L is a single bond, >O, >S, or >C(-A ^H ) ₂ ,

A ^H is hydrogen, aryl, or heteroaryl, and two A ^Hs in >C(-A ^H ) ₂ may be bonded to each other;

In the formulas (EH-1A) to (EH-1D),

Ar is a heteroaryl ring containing N = C as a partial structure constituting the ring,

Z is a single bond, -O-, -S-, or -N(-A ^E )-;

The carbon atom adjacent to the carbon atom to which Z is bonded and A ^E to which Z is bonded may be bonded to each other by L,

L is a single bond, >O, >S, or >C(-A ^E ) ₂ ,

A ^E is aryl, heteroaryl, or triarylsilyl, and two A ^E in >C(-A ^E ) ₂ may be bonded to each other;

X is C, P, or S;

When X is C, n = 2, m = 1,

When X is P, n = 3 and m = 1,

When X is S, n=2 and m=1-2;

In formula (EH-1b),

R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each independently hydrogen or a substituent;

X ¹ and X ² are each independently >NR ^NX2 , >O, >C(-R ^CX2 ) ₂ , >S, or >Se, and X ¹ and X ² are both >C(-R ^CX2 ) ₂ There is no case where this

R ^NX2 and R ^CX2 are each independently hydrogen or a substituent, and R ^NX2 and R ^CX2 each independently may be bonded to at least one of the a, b and c rings via a linking group or a single bond,

Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , and Y ⁶ are each independently =C(-R ^Y )- or =N-, and at least one is =N-;

R ^Y is each independently hydrogen or a substituent;

Adjacent groups of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ , and R ^Y are bonded to each other to form an aryl ring or a heteroaryl ring together with at least one ring of ring a, ring b, and ring c; It may be present, and at least one hydrogen in the formed ring is aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (even if two aryls are bonded through a single bond or a linking group) ), may be substituted with alkyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen in these may be further substituted with aryl, heteroaryl, alkyl or cycloalkyl,

At least one hydrogen in the compound and structure represented by formula (EH-1b) may be substituted with cyano, halogen or deuterium.

<11> The organic electroluminescent device according to <10>, wherein the hole-transporting host material is HH-1-12 and the electron-transporting host material is EH-1-94.

<12> The organic electroluminescent device according to any one of <1> to <11>, wherein the light emitting layer contains a compound capable of emitting thermally activated delayed fluorescence as the assisting dopant.

<13> The organic electroluminescent device according to any one of <1> to <11>, wherein the light-emitting layer contains a compound capable of emitting phosphorescence as the assisting dopant.

<14> A display device or lighting device provided with the organic electroluminescent element according to any one of <1> to <13>.

According to the present invention, an organic EL device using a novel material combination is provided. The organic EL device of the present invention has a high external quantum efficiency and a long life.

1 is a schematic cross-sectional view showing an example of an organic electroluminescent device.
2 is an energy level diagram showing energy relationships among a host, an assisting dopant, and an emitting dopant of a TAF device using a typical fluorescent dopant.
3 is an energy level diagram showing an example of an energy relationship among a host, an assisting dopant, and an emitting dopant in an organic electroluminescent device according to one embodiment of the present invention.

In the following, the present invention will be described in detail. The description of the constitutional requirements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit. In addition, in this specification, "hydrogen" in description of structural formula means "hydrogen atom (H)." Similarly, "carbon atom (C)" may be referred to as "carbon".

In this specification, "adjacent groups" means two groups respectively bonded to two adjacent atoms (two atoms directly bonded by covalent bonds) in the structural formula.

In the present specification, "Me" is methyl, "Et" is ethyl, "nBu" is n-butyl (normal butyl), "tBu" is t-butyl (tertiary butyl), "iBu" is isobutyl, "secBu" ” is secondary butyl, “nPr” is n-propyl (normal propyl), “iPr” is isopropyl, “tAm” is t-amyl, “2EH” is 2-ethylhexyl, “tOct” is t-octyl, “ Ph" is phenyl, "Mes" is mesityl (2,4,6-trimethylphenyl), "Ad" is 1-adamantyl, "Tf" is trifluoromethanesulfonyl, "TMS" is trimethylsilyl, "D" represents deuterium.

In this specification, an organic electroluminescent element is sometimes referred to as an organic EL element.

In the present specification, chemical structures and substituents are expressed in terms of carbon number, but the number of carbon atoms in the case where a substituent is substituted in a chemical structure or a substituent is further substituted in a substituent means the number of carbon atoms in each chemical structure or substituent, It does not mean the total carbon number of a chemical structure and a substituent, or the total number of carbon atoms of a substituent and a substituent. For example, "substituent B of carbon number Y substituted with substituent A of carbon number X" means that "substituent A of carbon number X" is substituted for "substituent B of carbon number Y", and carbon number Y is substituent A and substituent It is not the carbon number of the sum of B. Further, for example, "substituent B of carbon number Y substituted with substituent A" means that "substituent A (with no carbon number limitation)" is substituted for "substituent B of carbon number Y", and carbon number Y is substituted by substituent A and It is not the carbon number of the sum of the substituents B.

0. Description of rings and substituents

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

Examples of the "aryl ring" in the present specification include aryl rings having 6 to 30 carbon atoms, preferably aryl rings having 6 to 16 carbon atoms, more preferably aryl rings having 6 to 12 carbon atoms, and 6 to 12 carbon atoms. An aryl ring of ~10 is particularly preferred.

Specific examples of the "aryl ring" include a monocyclic benzene ring, a bicyclic biphenyl ring, a condensed bicyclic naphthalene ring, an indene ring, and a tricyclic terphenyl ring (m-terphenyl, o-terphenyl, p-terphenyl). ), a condensed tricyclic ring, acenaphthylene ring, a fluorene ring, a phenalene ring, a phenanthrene ring, anthracene ring, a condensed tetracyclic triphenylene ring, a pyrene ring, a naphthacene ring, a chrysene ring, a condensed five ring perylene ring, A pentacene ring etc. are mentioned. The fluorene ring, benzofluorene ring, and indene ring also include structures in which fluorene rings, benzofluorene rings, cyclopentane rings, and the like are spiro bonded, respectively. Further, in the fluorene ring, benzofluorene ring and indene ring, two of the two hydrogens of methylene in the structure are substituted with an alkyl such as methyl as a first substituent described below, respectively, and a dimethylfluorene ring, dimethylbenzofluorene Rings, dimethylindene rings, and the like are also included.

Examples of the "heteroaryl ring" in the present specification include a heteroaryl ring having 2 to 30 carbon atoms, a heteroaryl ring having 2 to 25 carbon atoms is preferable, and a heteroaryl ring having 2 to 20 carbon atoms is more preferable. A heteroaryl ring having 2 to 15 carbon atoms is more preferred, and a heteroaryl ring having 2 to 10 carbon atoms is particularly preferred. Examples of the "heteroaryl ring" include heterocycles containing 1 to 5 heteroatoms selected from oxygen, sulfur, nitrogen, selenium, phosphorus, and tellurium in addition to carbon as ring-constituting atoms.

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 furazane ring), a thiadiazole ring, a triazole ring, and a tetracyclic ring. sol ring, pyrazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring, indole ring, isoindole ring, 1H-indazole ring, benzoimidazole ring, benzooxazole ring, benzothiazole ring, 1H-benzo Triazole ring, quinoline ring, isoquinoline ring, cinnoline ring, quinazoline ring, quinoxaline ring, phthalazine ring, naphthyridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenoxathiine ring, Phenoxazine ring, phenothiazine ring, phenazine ring, phenazacillin ring, indolizine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, thianthrene ring, indolocarbazole ring, benzoindolocarbazole ring, dibenzoindolocarbazole ring, naphthobenzofuran ring, dioxin ring, dihydroacridine ring, xanthene ring, thioxanthene ring, di A benzodioxin ring, a benzoselenophene ring, etc. are mentioned. In addition, in the dihydroacridine ring, xanthene ring, and thioxanthene ring, two of the two hydrogens of methylene in the structure are substituted with an alkyl such as methyl as the first substituent described below, respectively, and a dimethyldihydroacridine ring, a dimethylxanthene ring, It is also preferable to be a dimethylthioxanthene ring or the like. Examples of the "heteroaryl ring" include a bipyridine ring, phenylpyridine ring, and pyridylphenyl ring, which are bicyclic rings, and terpyridine rings, bispyridylphenyl rings, and pyridylbiphenyl rings, which are tricyclic rings. In addition, a "heteroaryl ring" shall also include a pyran ring.

In this specification, a substituent may be substituted with another 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 other substituent or is not substituted. In some cases, "may be substituted" with the same meaning. In this specification, the specific substituent at this time may be referred to as a "first substituent" and the other substituent described above as a "second substituent".

In the present specification, the substituent group Z is,

aryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

heteroaryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

diarylamino which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two aryls may be bonded to each other via a linking group);

diheteroarylamino which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two heteroaryls may be bonded to each other via a linking group);

Arylheteroarylamino which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (aryl and heteroaryl may be bonded to each other through a linking group);

diarylboryl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl (two aryls may be bonded via a single bond or a linking group);

Alkyl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;

cycloalkyl which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl;

alkoxy which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl and cycloalkyl;

aryloxy which may be substituted with at least one group selected from the group consisting of aryl, heteroaryl, alkyl and cycloalkyl, and

made from substituted silyl.

The aryl as the second substituent in each group of the substituent group Z may be further substituted with aryl, heteroaryl, alkyl, or cycloalkyl, and similarly, the heteroaryl as the second substituent is aryl, heteroaryl, alkyl, or cycloalkyl. It may be substituted by alkyl.

In the present specification, when referring to a "substituent", any one selected from the substituent group Z when there is no separate explanation (for example, a separate description of substituents such as aryl rings in the A ring, etc., and R ^Z ) It should be the spirit of For example, when a group regarded as "substituted or unsubstituted" is substituted, the group should just be substituted with at least one group selected from the substituent group Z.

In the present specification, “aryl” refers to, for example, aryl having 6 to 30 carbon atoms, and preferably includes aryl having 6 to 20 carbon atoms, aryl having 6 to 16 carbon atoms, aryl having 6 to 12 carbon atoms, or aryl having 6 to 12 carbon atoms. aryl of 10, etc.

The specific "aryl" is. For example, monocyclic phenyl, bicyclic biphenylyl (2-biphenylyl, 3-biphenylyl, or 4-biphenylyl), condensed bicyclic naphthyl (1-naphthyl or 2-naphthyl) ethyl), tricyclic terphenylyl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, o-ter Phenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, or p-terphenyl-4- 1), condensed tricyclic, acenaphthylene-(1-, 3-, 4-, or 5-)yl, fluorene-(1-, 2-, 3-, 4-, or 9-)yl, phenalen-(1- or 2-)yl, phenanthrene-(1-, 2-, 3-, 4-, or 9-)yl, or anthracene-(1-, 2-, or 9-)yl, Quaternary phenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-yl, 5'-phenyl-m-terphenyl-4-yl, or m-quaterphenyl), condensed tetracyclic, triphenylene-(1- or 2-)yl, pyrene-(1-, 2-, or 4-)yl, or naphthacene-(1-, 2-, or 5-)yl, or condensed pentacyclic, perylene-(1-, 2-, or 3-)yl, or pentacene-(1-, 2-, 5-, or 6-)yl, and the like. . In addition, the monovalent group of spirofluorene, etc. are mentioned.

In the aryl as the second substituent, the aryl is aryl such as phenyl (specific examples are groups described above), alkyls such as methyl (specific examples are groups described later), and cycloalkyls such as cyclohexyl or adamantyl. (Specific examples are groups described later) and structures substituted with at least one group selected from the group consisting of are also included.

One example thereof is a group in which the ninth position of fluorenyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl.

"Arylene" is, for example, arylene having 6 to 30 carbon atoms, and preferably includes arylene having 6 to 20 carbon atoms, arylene having 6 to 16 carbon atoms, arylene having 6 to 12 carbon atoms, or arylene having 6 to 12 carbon atoms. Arylene of 10, etc.

A specific "arylene" includes, for example, a divalent group obtained by removing one hydrogen from the aforementioned "aryl" (monovalent group).

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

Specific "heteroaryls" include, for example, pyrroleyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyri Dill, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindoleyl, 1H-indazolyl, benzoimidazolyl, benzooxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl , isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl, purinyl, pteridinyl, carbazolyl, acridinyl, phenoxathinyl, phenoxazinil, phenothiazinil, phenazinyl, phenazacillinyl, indolizinyl, furanil, benzofuranil, isobenzofuranil, dibenzofuranil, naphthobenzofuranil, thienyl, benzothienyl, Isobenzothienyl, dibenzothienyl, naphthobenzothienyl, benzophosphoryl, dibenzophosphoryl, monovalent group of benzophosphole oxide ring, monovalent group of dibenzophosphole oxide ring, furazanyl, thianthrenyl , indolocarbazolyl, benzoindolocarbazolyl, dibenzoindolocarbazolyl, imidazolinyl, or oxazolinyl, and the like. In addition, a monovalent group of spiro[fluorene-9,9'-xanthene], a monovalent group of spirobi[silafluorene], and a monovalent group of benzoselenophene are exemplified.

In the heteroaryl as the second substituent, the heteroaryl is aryl such as phenyl (specific examples are groups described above), alkyls such as methyl (specific examples are groups described later), and cyclohexyl or adamantyl such as cyclohexyl. Structures substituted with at least one group selected from the group consisting of alkyl (specific examples of which will be described later) are also included.

One example thereof is a group in which the ninth position of carbazolyl as the second substituent is substituted with an aryl such as phenyl, an alkyl such as methyl, or a cycloalkyl such as cyclohexyl or adamantyl. In addition, groups in which nitrogen-containing heteroaryl such as pyridyl, pyrimidinyl, triazinyl, and carbazolyl is further substituted with phenyl or biphenylyl are also included in heteroaryl as the second substituent.

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

Specific examples of the "heteroarylene" include a divalent group obtained by removing one hydrogen from the aforementioned "heteroaryl" (monovalent group).

"Diarylamino" is amino in which two aryls are substituted, and the description of "aryl" described above can be cited for details of this aryl.

"Diheteroarylamino" is an amino group in which two heteroaryls are substituted, and the description of "heteroaryl" described above can be cited for details of this heteroaryl.

"Arylheteroarylamino" is an amino group in which aryl and heteroaryl are substituted, and the description of "aryl" and "heteroaryl" described above can be cited for details of the aryl and heteroaryl.

The two aryls in diarylamino as the first substituent may be bonded to each other via a linking group, and the two heteroaryls in diheteroarylamino as the first substituent may be bonded to each other via a linking group. The aryl and heteroaryl of arylheteroarylamino as a substituent may be bonded to each other through a linking group. Here, the description of "bonding via a linking group" indicates that, for example, two phenyls of diphenylamino form a bond with a linking group, as shown below. This statement also applies to diheteroarylamino and arylheteroarylamino, formed from aryls or heteroaryls.

(* indicates a binding position)

Specifically as a linking group, >O, >NR ^X , >C(-R ^X ) ₂ , -C(-R ^X )=C(-R ^X )-, >Si(-R ^X ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se. R ^X is each independently an alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. In addition, >C(-R ^X ) ₂ , -C(-R ^X )=C(-R ^X )-, and >Si(-R ^X ) ₂ Two R ^X in each are a single bond or a linking group X They may be bonded to each other via ^Y to form a ring. Examples of X ^Y include >O, >NR ^Y , >C(-R ^Y ) ₂ , >Si(-R ^Y ) ₂ , >S, >CO, >CS, >SO, >SO ₂ , and >Se. and R ^Y are each independently alkyl, cycloalkyl, aryl or heteroaryl, which may be substituted with alkyl, cycloalkyl, aryl or heteroaryl. However, when ^XY is >C(-R ^Y ) ₂ and >Si(-R ^Y ) ₂ , two R ^Y are bonded together to form no further ring. Furthermore, alkenylene is also mentioned as a linking group. Any hydrogen of the alkenylene may be each independently substituted with R ^2X , and each R ^2X is independently alkyl, cycloalkyl, substituted silyl, aryl, and heteroaryl, which are alkyl, cycloalkyl, substituted silyl, or aryl. may be substituted. Two R ^{X '} s in -C(-R ^X )=C(-R ^X )- may be bonded to each other to form an aryl (benzene ring, etc.) or heteroaryl ring together with C=C to which they are bonded. . That is, -C(-R ^X )=C(-R ^X )- may be arylene (1,2-phenylene, etc.) or heteroarylene.

In addition, in the present specification, when simply described as “diarylamino,” “diheteroarylamino,” or “arylheteroarylamino,” unless otherwise specified, each “two aryls of diarylamino are a linking group may be bonded through", "the two heteroaryls of the diheteroarylamino may be bonded to each other through a linking group", and "the aryl and heteroaryl of the arylheteroarylamino may be bonded to each other through a linking group" It is said that the explanation is added.

"Diarylboryl" is a boryl in which two aryls are substituted, and the description of "aryl" described above can be cited for details of this aryl. In addition, these two aryls are single bonds or linking groups (for example, -CH=CH-, -CR=CR-, -C≡C-, >NR, >O, >S, >C(-R) ₂ , >Si(-R) ₂ , or >Se). Here, the R of -CR=CR-, R of >NR, 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 R may be further substituted with aryl, heteroaryl, alkyl, alkenyl, alkynyl, or cycloalkyl. Further, two adjacent Rs may be bonded to form a ring to form cycloalkylene, arylene, and heteroarylene. For the details of the substituents listed here, the description of "aryl", "arylene", "heteroaryl", "heteroarylene", and "diarylamino" described above, and "alkyl" and "alkyl" described later Descriptions of "kenyl", "alkynyl", "cycloalkyl", "cycloalkylene", "alkoxy", and "aryloxy" can be cited. In addition, when it is simply described as "diaryl boryl" in this specification, unless otherwise limited, "two aryls of diaryl boryl may be bonded to each other through a single bond or a linking group". It is said that there is

"Alkyl" may be either straight-chain or branched chain, and is, for example, straight-chain alkyl having 1 to 24 carbon atoms or branched-chain alkyl having 3 to 24 carbon atoms, preferably, alkyl having 1 to 18 carbon atoms (carbon atoms 3 to 24). branched chain alkyl of 18), alkyl of 1 to 12 carbon atoms (branched chain alkyl of 3 to 12 carbon atoms), alkyl of 1 to 6 carbon atoms (branched chain alkyl of 3 to 6 carbon atoms), alkyl of 1 to 5 carbon atoms (3 carbon atoms) ~5 branched chain alkyl), C1-4 alkyl (C3-4 branched chain alkyl), and the like.

Specific "alkyl" includes, for example, methyl, ethyl, n-propyl, isopropyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1,1 ,2,2-tetramethylpropyl, 1-ethyl-1,2,2-trimethylpropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-ethylbutyl, 1,1-dimethylbutyl, 3 ,3-dimethylbutyl, 1,1-diethylbutyl, 1-ethyl-1-methylbutyl, 1-propyl-1-methylbutyl, 1,1,3-trimethylbutyl, 1-ethyl-1,3-dimethyl Butyl, 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-methyl heptyl, 1-hexylheptyl, 1,1-dimethylheptyl, 2,2-dimethylheptyl, 2,6-dimethyl-4-heptyl, n-octyl, t-octyl (1,1,3,3-tetramethylbutyl), 1,1-dimethyloctyl, n-nonyl, n-decyl, 1-methyldecyl , n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, or n-eicosyl.

"Alkylene" is a divalent group obtained by removing any one of the "alkyl" hydrogens, and is, for example, methylene, ethylene, or propylene.

Regarding "alkenyl", the description of "alkyl" described above can be referred to, and it is a group in which the C-C single bond in the structure of "alkyl" is substituted with a C=C double bond, and not only one but two or more groups Also included are groups in which a bond is substituted with a double bond (also called alkadien-yl or alkathien-yl).

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

Regarding "alkynyl", the description of "alkyl" described above can be referred to, and it is a group in which the C-C single bond in the structure of "alkyl" is substituted with a C≡C triple bond, and not only one but two or more groups Also included are groups in which a bond is replaced by a triple bond (also called alkadiyn-yl or alkathien-yl).

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

Specific "cycloalkyl" includes, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, or alkyls having 1 to 5 carbon atoms or 1 to 4 carbon atoms (especially methyl) substituents, 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, bi cyclo[2.2.1]heptyl (norbornyl), bicyclo[2.2.2]octyl, adamantyl, diamantyl, decahydronaphtharenyl, or decahydroazulenyl, and the like.

"Cycloalkylene" is, for example, a cycloalkylene having 3 to 24 carbon atoms, preferably a cycloalkylene having 3 to 20 carbon atoms, a cycloalkylene having 3 to 16 carbon atoms, or a cycloalkylene having 3 to 14 carbon atoms. , C3-C12 cycloalkylene, C5-10 cycloalkylene, C5-8 cycloalkylene, C5-6 cycloalkylene, or C5 cycloalkylene.

Specific examples of "cycloalkylene" include a structure made into a divalent group by removing one hydrogen from the aforementioned "cycloalkyl" (monovalent group).

"Cycloalkenyl" is a group having a structure in which a single bond between two carbon atoms in at least one set of the above-mentioned "cycloalkyl" is a double bond (eg, -CH ₂ -CH ₂ - is - a group substituted with CH=CH-), and groups not corresponding to aryl are exemplified. Specifically, 1-cyclohexenyl, 1-cyclopentenyl, etc. are mentioned.

"Alkoxy" is a group represented by "Alk-O- (Alk is alkyl)", and the description of "alkyl" described above can be cited for details of this alkyl.

"Aryloxy" is a group represented by "Ar-O- (Ar is aryl)", and the description of "aryl" described above can be cited for details of this aryl.

"Substituted silyl" is, for example, silyl substituted with at least one of aryl, alkyl, and cycloalkyl, preferably triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, or alkyl dicycloalkylsilyl.

"Triarylsilyl" is a silyl group substituted with three aryls, and the description of "aryl" described above can be cited for details of this aryl.

Specific examples of "triarylsilyl" include triphenylsilyl, diphenylmononaphthylsilyl, monophenyldinaphthylsilyl, and trinaphthylsilyl.

"Trialkylsilyl" is a silyl group substituted with three alkyls, and the description of "alkyl" described above can be cited for details of this alkyl.

Specific "trialkylsilyl" includes, for example, trimethylsilyl, triethylsilyl, trin-propylsilyl, triisopropylsilyl, trin-butylsilyl, triisobutylsilyl, tris-butylsilyl, trit- Butylsilyl, ethyldimethylsilyl, n-propyldimethylsilyl, isopropyldimethylsilyl, n-butyldimethylsilyl, isobutyldimethylsilyl, s-butyldimethylsilyl, t-butyldimethylsilyl, methyldiethylsilyl, n-propyldi Ethylsilyl, isopropyldiethylsilyl, n-butyldiethylsilyl, s-butyldiethylsilyl, t-butyldiethylsilyl, methyl di-n-propylsilyl, ethyl di-n-propylsilyl, n-butyldi n- propylsilyl, s-butyldin-propylsilyl, t-butyldin-propylsilyl, methylisopropylsilyl, ethyldiisopropylsilyl, n-butyldiisopropylsilyl, s-butyldiisopropylsilyl, or t -Butyldiisopropylsilyl, etc.

"Tricycloalkylsilyl" is a silyl group substituted with three cycloalkyls, and the description of "cycloalkyl" described above can be cited for details of this cycloalkyl.

Specific "tricycloalkylsilyl" is, for example, tricyclopentylsilyl or tricyclohexylsilyl.

"Dialkylcycloalkylsilyl" is a silyl group substituted with two alkyls and one cycloalkyl, and the descriptions of "alkyl" and "cycloalkyl" described above can be cited for details of these alkyls and cycloalkyls. .

"Alkyldicycloalkylsilyl" is a silyl group substituted with one alkyl and two cycloalkyls, and for details of these alkyls and cycloalkyls, the descriptions of "alkyl" and "cycloalkyl" described above can be cited. .

<When two groups bonded to the same atom bond to each other>

In the present specification, when it is said that two groups bonded to the same atom may be bonded to each other to form a ring, they may be bonded by a single bond or a linking group (these are collectively referred to as a linking group), and as the linking group, -CH ₂ -CH ₂ -, -CHR-CHR-, -CR ₂ -CR ₂ -, -CH=CH-, -CR=CR-, -C≡C-, -N(-R)-, -O-, - S-, -C(-R) ₂ -, -Si(-R) ₂ -, or -Se-, and examples thereof include the following structures. In addition, R of -CHR-CHR-, R of -CR ₂ -CR ₂ -, R of -CR=CR-, R of -N(-R)-, R of -C(-R) ₂ -, and R in -Si(-R) ₂ - are each independently hydrogen, aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, alkyl which may be substituted with cycloalkyl , alkenyl which may be substituted with alkyl or cycloalkyl, alkynyl which may be substituted with alkyl or cycloalkyl, or cycloalkyl which may be substituted with alkyl or cycloalkyl. Further, two adjacent Rs may be bonded to form a ring to form cycloalkylene, arylene, or heteroarylene.

As a bonding group, -CR=CR-, -N(-R)-, -O-, -S-, -C(-R) ₂ -, -Si(-R) ₂ -, and - as a single bond or a linking group. Se- is preferable, and -CR=CR-, -N(-R)-, -O-, -S-, and -C(-R) ₂ - as a single bond or linking group are more preferable, and a single bond, -CR=CR-, -N(-R)-, -O-, and -S- as linking groups are more preferred, and a single bond is most preferred.

The position at which two R are bonded by a bonding group is not particularly limited as long as it can be bonded, but it is preferable to bond at the most adjacent position, for example, when the two groups are phenyl, "C" in phenyl or It is preferable to bond to each other at ortho (second position) positions with the bonding position (first position) of "Si" as a reference (see the above structural formula).

1. organic electric field of light emitting element of the light emitting layer material of construction

The organic electroluminescent device of the present invention has a pair of electrodes composed of an anode and a cathode, and a light emitting layer disposed between the pair of electrodes. At least one light emitting layer included in the organic electroluminescent device of the present invention includes at least two selected from the group consisting of an emitting dopant, a hole transporting host material, an electron transporting host material, and an assisting dopant material.

Each of these materials is described below.

1-1. Emitting dopant

In the organic electroluminescent device of the present invention, the emitting dopant is a polyaromatic compound represented by formula (1), a polymer compound obtained by polymerizing the polycyclic aromatic compound as a monomer, a polymer crosslinked product obtained by further crosslinking the polymer compound, and at least one selected from the group consisting of a pendant-type polymer compound obtained by reacting the polycyclic aromatic compound with a main chain-type polymer, and a pendant-type polymer crosslinked product obtained by further crosslinking the pendant-type polymer compound. In this specification, these may be collectively referred to as "a polycyclic aromatic compound represented by formula (1), etc."

The polyaromatic compound or the like represented by Formula (1) is a "thermally activated delayed fluorescent substance" and can exhibit thermally activated delayed fluorescence (TADF). In the "thermally activated delayed phosphor", by reducing the energy difference between the lowest singlet excited state and the lowest triplet excited state, inverse intersystem crossing from the lowest triplet excited state to the lowest singlet excited state, which usually has a low transition probability. Migration is produced with high efficiency, and light emission from singlets (thermally activated delayed fluorescence, TADF) is expressed. In normal fluorescence emission, 75% of triplet excitons generated by current excitation pass through the thermal deactivation pathway, so they cannot be extracted as fluorescence. On the other hand, in TADF, all excitons can be used for fluorescence, and a highly efficient organic EL device is realized. In the present invention, high device efficiency and long device lifetime are realized by using such a "heat-activated delayed phosphor" together with the host material and assisting dopant.

Generally, it is considered that the faster the delayed fluorescence, the better the TADF property. Specifically, when a light emitting material having a delayed fluorescence lifetime of 20 μsec or less is used as an emitting dopant in a light emitting device, high device efficiency and long device life can be obtained. The delayed fluorescence lifetime is preferably less than 20 μsec, more preferably 10 μsec or less, and most preferably 5 μsec or less.

Also, in general, the smaller the value of ΔES1T1 is, the better the TADF performance is. Meanwhile, ΔES1T1 is an energy difference between the lowest singlet excitation energy level (ES1) and the lowest triplet excitation energy level (ET1). Specifically, the value of ΔES1T1 is preferably 0.20 eV or less, more preferably 0.15 eV or less, and particularly preferably 0.10 eV or less.

The polyaromatic compound or the like represented by Formula (1) is, in the organic electroluminescent device of the present invention, an emission dopant of a TADF device using a hole-transporting host material and an electron-transporting host material, and another thermally activated delayed phosphor. organic electroluminescent device (TADF-assisted fluorescent device, TAF device) using as an assisting dopant, an organic electroluminescent device using a phosphorescent material as an assisting dopant (phosphor-assisted fluorescent device) -sensitized fluorescent device, PSF device) is used as an emitting dopant. The present inventors use a polyaromatic compound or the like represented by formula (1) together with at least two selected from the group consisting of a hole-transporting host material, an electron-transporting host material, and an assisting dopant material to form a light emitting layer. , it was found that a long-life organic EL device giving high efficiency green light emission can be manufactured.

1-1-1. expressed by equation (1) polycyclic aromatic compound

<Description of the overall structure of the compound>

The polyaromatic compound represented by formula (1) is preferably represented by formula (1B). Formula (1B) corresponds to a structure in which specific rings are selected as the A ring, B ring, D ring, E ring, F ring, and G ring in formula (1). In that sense, each ring in each formula is represented by lowercase letters "a", "b", "d", "e", "f" and "g".

The polyaromatic compound represented by Formula (1) has a structure in which aromatic rings are connected with hetero elements such as boron, nitrogen, oxygen, and sulfur, and has a large HOMO-LUMO gap (band gap Eg in the thin film). This is because the 6-membered ring containing a hetero element has low aromaticity, and the reduction of the HOMO-LUMO gap due to the expansion of the conjugated system is suppressed. In the polyaromatic compound represented by formula (1), the HOMO-LUMO gap can be arbitrarily changed depending on the type of hetero element and the connection method. This is considered to be caused by the fact that the energies of HOMO and LUMO can be moved arbitrarily according to the spatial spread and energy of vacant orbits or lone pairs of hetero elements. For example, as a polyaromatic compound represented by formula (1), a compound in which Y is B (boron) has a deeper LUMO or a narrower band gap Eg compared to a polyaromatic compound having a smaller B (Y), giving a green color. indicates luminescence.

In this polyaromatic compound, SOMO1 and SOMO2 in an excited state are localized on each atom by electronic perturbation of a hetero element, so the half-width of the fluorescence emission peak is narrow, and when used as a dopant in an organic EL device, emission of high color purity occurs. is obtained For the same reason, ΔE _S1T1 is reduced to show thermally activated delayed fluorescence, and high efficiency can be obtained when used as an emitting dopant for an organic EL device.

Moreover, since the energies of HOMO and LUMO can be arbitrarily moved by introducing a substituent, it is possible to optimize the ionization potential or electron affinity according to the surrounding materials. However, the present invention is not particularly limited to this principle.

Hereinafter, the structure represented by Formula (1) is demonstrated.

<Description of Ring Structure in Compound>

In formula (1), "A", "B", "D", "E", "F", and "G" in circles are symbols representing ring structures represented by respective circles. The structure represented by formula (1) and formula (1B) is composed of boron, oxygen, nitrogen, and sulfur in at least seven aromatic rings as ring A, ring B, ring c, D ring, E ring, F ring, and G ring. It has a structure in which a ring structure is further formed by connecting with a hetero element such as. The ring structure formed is a condensed ring structure composed of at least 13 rings.

In Formula (1), A ring, B ring, D ring, E ring, F ring, and G ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring. In the substituted or unsubstituted aryl ring or substituted or unsubstituted heteroaryl ring in the A ring, B ring, D ring, E ring, F ring, and G ring of the structure represented by formula (1), " As the substituent in the case of “substituted or unsubstituted (substituted or unsubstituted)”, at least one substituent selected from the group obtained by adding a substituent represented by the formula (A30) described later to the substituent group Z is exemplified. For the preferable range of the substituent, the preferable range of ^RZ in formula (1B) described later can be referred.

Each of the A ring and the D ring forms a trivalent group having bonds at three consecutive carbon atoms of the aryl ring or heteroaryl ring in the structure. Each of these three bonds binds to N, X, and Y. When ring A or ring D is bonded to R ^NX , R ^CX or R ^IX , it may be a tetravalent or pentavalent group. Among the A and D rings, the ring containing carbon having the above three bonds as a ring constituent element is preferably a 5-membered ring or a 6-membered ring, and more preferably a 6-membered ring. This ring may further condense with another ring. A benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring etc. are mentioned as an example of a 6-membered ring. Examples of condensation of a 6-membered ring with another ring include a naphthalene ring, a quinoline ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring. Examples of the 5-membered ring include a furan ring, a thiophene ring, a pyrrole ring, and a thiazole ring. Examples of further condensation of a 5-membered ring with another ring include a benzofuran ring, a benzothiophene ring, and an indole ring.

Ring B, E ring, F ring, and G ring all form a divalent group having a bond at two carbon atoms adjacent to each other in the ring of the aryl ring or heteroaryl ring in the structure. Ring B and E are bonded to X and Y at the above two bonds, respectively, and ring F and G are bonded to Y and N at the above two bonds, respectively. When the B ring and the E ring are further bonded to R ^NX , R ^CX or R ^IX , they may be trivalent or tetravalent groups. Among the B rings and the C rings, the ring containing carbon having the above two bonds as a ring constituent element is preferably a 5-membered ring or a 6-membered ring, and more preferably a 6-membered ring. This ring may further condense with another ring. A benzene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring etc. are mentioned as an example of a 6-membered ring. Examples of further condensation of a 6-membered ring with another ring include a naphthalene ring, a quinoline ring, a dibenzofuran ring, a dibenzothiophene ring, and a carbazole ring. Examples of the 5-membered ring include a furan ring, a thiophene ring, a pyrrole ring, and a thiazole ring. Examples of further condensation of a 5-membered ring with another ring include a benzofuran ring, a benzothiophene ring, and an indole ring.

Preferred ring structures of A ring, B ring, D ring, E ring, F ring, and G ring in formula (1) are the a ring, b ring, d ring, e ring in formula (1B), respectively; It is represented as ring f and ring G.

<Description of Z>

Z in c-ring of formula (1) is -C(-R ^Z )= or -N=. R ^Z is each independently hydrogen or a substituent. As the substituent, at least one substituent selected from the group obtained by adding a substituent represented by the formula (A30) described below to the substituent group Z, unsubstituted alkyl is preferable, and methyl is more preferable. R ^Z is preferably hydrogen. As Z in the c ring, -C(-H)= is preferable.

Z in the c ring of formula (1B) has the same meaning as Z in the c ring in formula (1), and the preferred range is also the same. The other Z in formula (1B) has the same meaning as Z in formula (1), but adjacent Z's may have the following structures together.

First, when all Z's in Z=Z are -C(-R ^Z )=, two R ^Z 's may be bonded to each other to form an aryl ring or a heteroaryl ring. The formed aryl ring or heteroaryl ring may each have a substituent. Examples of the substituent at this time include at least one substituent selected from the group obtained by adding a substituent represented by the formula (A30) described later to the substituent group Z. The preferred range is the same as the preferred range of R ^Z . Further, Z=Z may each independently be >NR, >O, >C(-R) ₂ , >Si(-R) ₂ , >S, or >Se. In this case, R in >NR, >C(-R) ₂ and >Si(-R) ₂ is each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted alkyl. , or a substituted or unsubstituted cycloalkyl. Two R of >C(-R) ₂ may be bonded to each other to form a ring, and two R of >Si(-R) ₂ may be bonded to each other to form a ring.

A structural example of a ring containing Z in formula (1B) is shown below as an example of a structure containing four Z and bonded to X and Y. Meanwhile, in the following formula, R has the same meaning as R ^Z , but does not mean hydrogen and does not mean that R bonds with each other. n is an integer from 0 to 4, and R ^N and R ^c are hydrogen, aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, or cycloalkyl which may be substituted. It is alkyl or cycloalkyl which may be substituted by alkyl, and two ^Rc 's may combine with each other to form a ring.

In each of the above partial structures, R is preferably alkyl, phenyl which may be substituted with alkyl, or a substituent represented by formula (A30). 0 or 1 is preferable, and, as for n, it is more preferable that it is 0.

Similar structural examples can be given for structures bonded to N and Y or structures containing three Zs.

In each of the rings a to g in formula (1B), it is preferable that 0 to 2 of Z are -N= and the remainder is -C(-R ^Z )=, and 0 to 1 are -N= and the remainder is - It is more preferable that C(-R ^Z )=, and it is even more preferable that all of them are -C(-R ^Z )=. In formula (1B), it is preferable that 0 to 8 Z are -N= and the remainder is -C(-R ^Z )=, and 0 to 3 Z are -N= and the remainder is -C(-R ^Z )= It is more preferable that 0 to 1 is -N= and the rest is more preferably -C(-R ^Z )=, and it is particularly preferable that all are -C(-R ^Z )=. As any one substituent selected from substituent group Z which is R ^Z , alkyl, phenyl which may be substituted with alkyl, biphenylyl which may be substituted with alkyl, terphenylyl which may be substituted with alkyl, substituted with alkyl or phenyl It is preferable that it is diphenylamino which may be, and carbazolyl which may be substituted by alkyl or phenyl. As the substituent R ^Z , the description of a preferred substituent described later can also be referred to. In each formula, 0 to 3 of R ^Z are substituents, and it is preferable that others are hydrogen. In particular, it is preferable that R ^Z which is a substituent exists at the para-position of Y. It is also preferable that R ^Z which is hydrogen at this position is substituted with halogen or cyano.

<Description of Y>

In Formula (1), Y is each independently B, P, P=O, or P=S, and it is preferable that it is B.

<Description of X>

In Formula (1), X is each independently >NR ^NX , >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S, or >Se. R ^NX is hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and 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 two R ^CX may be bonded to each other to form a ring, and 2 Two R ^IX 's may be bonded to each other to form a ring, and each of R ^NX , R ^CX , and R ^IX may be bonded to one or two rings to which X containing itself is bonded.

As X, >O, >NR ^NX , or >S are each independently preferable. R ^NX in >NR ^NX is preferably substituted or unsubstituted phenyl, substituted or unsubstituted biphenylyl, or substituted or unsubstituted triphenylyl, optionally substituted with alkyl, substituted with alkyl, Biphenylyl which may be present or triphenylyl which may be substituted with alkyl is more preferred, and phenyl which may be substituted with alkyl is still more preferred. In a structure in which Y is B, in order to obtain green light emission, it is preferable that at least one of X's is >NR ^NX , and it is more preferable that all X's are >NR ^NX . From the viewpoint of TADF properties, it is preferable that at least one is S.

<Explanation of the change in the ring structure due to the combination of X and the ring>

Each of R ^NX , R ^CX , and R ^IX in X may be bonded to one or two rings to which X containing itself is bonded through a single bond or a linking group. Specifically, in formula (1), R ^NX , R ^CX , and R ^IX in X bonded to ring A and ring B may be bonded to at least one of ring A or ring B through a single bond or a linking group; R ^NX , R ^CX and R ^IX in X bonded to the D and E rings may be bonded to at least one of the D and E rings through a single bond or a linking group. In formula (1B), R ^NX , R ^CX and R ^IX in X bonded to the a ring and the b ring are single bonds or linking groups, and Z in at least one of the a ring or the b ring (the carbon to which X is bonded may be bonded to Z adjacent to , and R ^NX , R ^CX , and R ^IX in X bonded to the d ring and the e ring are, by a single bond or a linking group, Z in at least one of the d ring or e ring (X may be bonded to Z) adjacent to the carbon to which is bonded.

Examples of linking groups when R ^NX , R ^CX and R ^IX are each bonded to a ring are -CH ₂ -CH ₂ -, -CHR-CHR-, -CR ₂ -CR ₂ -, -CH=CH-, -CR=CR -, -C≡C-, -N(-R)-, -O-, -S-, -C(-R) ₂ -, -Si(-R) ₂ -, or -Se-. there is. 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 preferable, and -CR=CR-, -N(-R)-, -O-, and -S- are more preferable R of “-CHR-CHR-”, R of “-CR ₂ -CR ₂ -”, R of “-CR=CR-”, R of “-N(-R)-”, R of “-C(- R of _2- ” and R of “-Si(-R) _2- ” are each independently hydrogen, aryl which may be substituted with alkyl or cycloalkyl, hetero which may be substituted with alkyl or cycloalkyl aryl, alkyl which may be substituted with cycloalkyl, alkenyl which may be substituted with alkyl or cycloalkyl, alkynyl which may be substituted with alkyl or cycloalkyl, or cycloalkyl which may be substituted with alkyl or cycloalkyl . In addition, two R's bonded to the same element may be bonded to form a ring. Furthermore, two adjacent Rs may be bonded to each other to form a cycloalkylene ring, an arylene ring, and a heteroarylene ring. This ring may also be substituted with alkyl or cycloalkyl.

Examples of structures in which R ^NX , R ^CX and R ^IX are each bonded to a ring are compounds having a ring structure in which X is included in condensed ring B', represented by the following formula (1"-A3), and the following formula (1 Compounds having a ring structure in which X is included in condensed ring A', represented by "-A4), are exemplified. Examples of the condensed ring formed include a carbazole ring, a phenoxazine ring, and a phenothiazine ring.

At least one of X connecting the ring structure and the ring structure is >NR ^NX , this R ^NX is optionally substituted alkyl or optionally substituted cycloalkyl, and by a linking group or single bond, ring A, ring B, You may have the structure connected with the aryl ring or heteroaryl ring in D ring or E ring.

For example, the following partial structure A10 may be formed by the above connection.

In formula (A10), R ^A1 to R ^A4 are each independently hydrogen, optionally substituted alkyl or optionally substituted cycloalkyl, and any 2 to 4 of R ^A1 to R ^A4 are linked to a linking group or a single bond may be bonded to each other, and is bonded to one ring of the two rings to which X is bonded at the position of two * and to the other ring at the position of **. That is, N in equation (A10) is N of >NR ^NX when X is >NR ^NX . The cyclic atoms bonded at the position of two * may be atoms adjacent to each other (preferably a carbon atom). The partial structure represented by formula (A10) includes NC bonds with weak bond dissociation energy (BDE), but because there is another bond forming a ring, the reverse reaction (recombination reaction) is promoted even when the NC bonds are cleaved. , resulting in a more stable structure. Therefore, in the organic EL device manufactured using the polyaromatic compound having such a structure, long device life is expected. When the structure represented by formula (A10) is included in the polycyclic aromatic compound, the number may be one or two.

In formula (A10), any two to four of R ^A1 to R ^A4 may be connected to each other by a linking group.

R ^A1 to R ^A4 are 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 It is preferable that ^A3 and R ^A4 ) are bonded to each other via a linking group or a single bond, and it is more preferable that R ^A1 and R ^A4 are bonded to each other via a linking group or single bond. Examples of the divalent group formed by bonding to each other include alkylene. At least one hydrogen in the alkylene may be substituted with alkyl or cycloalkyl, and at least one (preferably one) -CH ₂ - in the alkylene is -O- and -S- may be substituted with As the divalent group formed by bonding with each other, a straight-chain alkylene having 2 to 5 carbon atoms is preferable, a straight-chain alkylene having 3 or 4 carbon atoms is more preferable, and a straight-chain alkylene having 4 carbon atoms (-(CH ₂ ) ₄ -) more preferable It is particularly preferred that the straight-chain alkylene having 4 carbon atoms (-(CH ₂ ) ₄ -) be unsubstituted.

The remaining R ^A1 to R ^A4 not involved in the connection by the linking group are each independently preferably hydrogen or optionally substituted alkyl, more preferably optionally substituted alkyl having 1 to 6 carbon atoms, It is more preferable that it is unsubstituted C1-C6 alkyl, and it is most preferable that all are methyl.

That is, as the partial structure represented by formula (A10), a structure represented by the following formula (A11) is preferable.

In formula (A11), Me is methyl, and is bonded to one ring of the two rings to which X is bonded at two * positions and to the other ring at ** positions.

<Preferred substituents>

In the polyaromatic compound used as an emitter dopant (in other compounds used as a dopant), tertiary alkyl represented by the following formula (tR) as a substituent containing "alkyl" is ring A, ring B, As a substituent of the aryl ring or heteroaryl ring in the C ring and the D ring, it is one of particularly preferable ones. This is because the luminescence quantum yield (PLQY) is improved because the intermolecular distance is increased by such a bulky substituent. Further, a substituent in which the tertiary alkyl represented by the formula (tR) is substituted with another substituent as the second substituent is also preferable. Specifically, diarylamino substituted with tertiary alkyl represented by formula (tR), carbazolyl (preferably N-carbazolyl) substituted with tertiary alkyl represented by formula (tR), or formula (tR) and benzocarbazolyl (preferably N-benzocarbazolyl) substituted with tertiaryalkyl represented by (tR). Examples of substitution forms of groups represented by the formula (tR) in diarylamino, carbazolyl and benzocarbazolyl include examples in which some or all hydrogens of the aryl ring or benzene ring in these groups are substituted with groups represented by the formula (tR) can

In formula (tR), R ^a , R ^b , and R ^c are each independently an alkyl having 1 to 24 carbon atoms, and any -CH ₂ - in the alkyl may be substituted with -O-, and the formula ( The group represented by tR) has * as a binding position.

As "alkyl having 1 to 24 carbon atoms" for R ^a , R ^b and R ^c , either straight chain or branched chain may be used, and examples thereof include straight chain alkyl having 1 to 24 carbon atoms or branched chain alkyl having 3 to 24 carbon atoms; Alkyl of 1 to 18 carbon atoms (branched chain alkyl of 3 to 18 carbon atoms), alkyl of 1 to 12 carbon atoms (branched chain alkyl of 3 to 12 carbon atoms), alkyl of 1 to 6 carbon atoms (branched chain alkyl of 3 to 6 carbon atoms) , C1-C4 alkyl (C3-C4 branched chain alkyl).

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

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

Examples of the group represented by formula (tR) include t-butyl, t-amyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1-dimethylbutyl, 1-ethyl-1 -methylbutyl, 1,1,3,3-tetramethylbutyl, 1,1,4-trimethylpentyl, 1,1,2-trimethylpropyl, 1,1-dimethyl octyl, 1,1-dimethylpentyl, 1, 1-Dimethylheptyl, 1,1,5-trimethylhexyl, 1-ethyl-1-methylhexyl, 1-ethyl-1,3-dimethylbutyl, 1,1,2,2-tetramethylpropyl, 1-butyl- 1-methylpentyl, 1,1-diethylbutyl, 1-ethyl-1-methylpentyl, 1,1,3-trimethylbutyl, 1-propyl-1-methylpentyl, 1,1,2-trimethylpropyl, 1 -Ethyl-1,2,2-trimethylpropyl, 1-propyl-1-methylbutyl, 1,1-dimethylhexyl, etc. are mentioned. Of these, t-butyl and t-amyl are preferred.

As the substituent, a substituent represented by formula (A30) is also preferable.

In formula (A30),

Ak is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkyl, or substituted or unsubstituted cycloalkenyl, wherein at least One -CH ₂ - may be substituted with -O- or -S-;

R ^Ak is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl or substituted or unsubstituted cycloalkyl, and R ^Ak may be bonded to Ak by a linking group or a single bond. , * is a binding position.

In formula (A30), because Ak is the substituent described above, since it does not conjugate with the unshared electron pair on N, the unshared electron pair can be conjugated with the π electron of the bonding site, and compared to the case where aryl etc. are present at the same position, more Large wavelength changes are possible. In addition, the same applies to the effect on the multiple resonance effect, and a greater improvement in thermally activated delayed fluorescence (TADF) properties is possible.

R ^Ak is aryl which may be substituted with alkyl or cycloalkyl, heteroaryl which may be substituted with alkyl or cycloalkyl, preferably alkyl or cycloalkyl, aryl which may be substituted with alkyl, hetero which may be substituted with alkyl It is more preferably aryl, alkyl or cycloalkyl, further preferably aryl which may be substituted with alkyl, and particularly preferably phenyl which may be substituted with methyl.

In formula (A30), Ak is preferably an alkyl having 1 to 6 carbon atoms or a cycloalkyl having 3 to 14 carbon atoms, preferably an alkyl having 1 to 4 carbon atoms or a cycloalkyl having 3 to 8 carbon atoms, and having 1 to 4 carbon atoms. It is more preferably an alkyl of , and more preferably a methyl.

R ^Ak and Ak may be the same or different, and different ones are preferred.

R ^Ak may be bonded to Ak by a linking group or a single bond. Examples of the linking group at this time include >O, >S, and >Si(-R) ₂ . R in >Si(-R) ₂ is hydrogen, aryl having 6 to 12 carbon atoms, alkyl having 1 to 6 carbon atoms, or cycloalkyl having 3 to 14 carbon atoms. Examples of structures in which R ^Ak is bonded to Ak via a linking group or single bond include the following.

In each of the above formulas, * is a binding position.

The emission wavelength can be adjusted by the structural steric hindrance property, electron donating property, and electron withdrawing property of the substituent of the compound used as the dopant (assisting dopant or emitting dopant). It is preferably a group represented by the following structural formula, more preferably methyl, t-butyl, t-amyl, t-octyl, neopentyl, adamantyl, phenyl, o-tolyl, p-tolyl, 2, 4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl)phenyl) amino, carbazolyl, 3,6-dimethylcarbazolyl, 3,6-di-t-butylcarbazolyl and phenoxy, even more preferably methyl, t-butyl, t-amyl, t- Octyl, neopentyl, adamantyl, phenyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, diphenylamino, di-p-tolylamino, bis(p-(t-butyl ) phenyl) amino, carbazolyl, 3,6-dimethylcarbazolyl and 3,6-di-t-butylcarbazolyl. From the viewpoint of ease of synthesis, a higher steric hindrance is preferred for selective synthesis. Specifically, t-butyl, t-amyl, t-octyl, adamantyl, o-tolyl, p-tolyl, 2, 4-xylyl, 2,5-xylyl, 2,6-xylyl, 2,4,6-mesityl, di-p-tolylamino, bis(p-(t-butyl)phenyl)amino, 3, 6-dimethylcarbazolyl and 3,6-di-t-butylcarbazolyl are preferred.

In the following structural formula, * represents a binding position.

The polycyclic aromatic compound preferably has a structure containing at least one of tertiary alkyl (t-butyl or t-amyl, etc.), neopentyl or adamantyl represented by the above formula (tR), and is represented by the formula (tR) It is preferable to include the indicated tertiary alkyl (t-butyl or t-amyl, etc.). This is because the luminescence quantum yield (PLQY) is improved because the intermolecular distance is increased by such a bulky substituent. Moreover, as a substituent, diarylamino is also preferable. Furthermore, diarylamino substituted with a group of formula (tR), carbazolyl (preferably N-carbazolyl) substituted with a group of formula (tR), or benzocarbazolyl substituted with a group of formula (tR) ( preferably, N-benzocarbazolyl) is also preferred. Examples of the substitution form of the group of formula (tR) in diarylamino, carbazolyl and benzocarbazolyl include examples in which part or all of the hydrogen of the aryl ring or benzene ring in this group is substituted with the group of formula (tR) can

In Formula (1), the substituent represented by the following formula (A20) may be sufficient as the substituent of the aryl ring or heteroaryl ring in A ring, B ring, D ring, E ring, F ring, and G ring.

The substituent represented by formula (A20) is bonded to two atoms adjacent to each other on the ring of the aryl ring or heteroaryl ring at two * points,

In formula (A20), L is >NR, >O, >Si(-R) ₂ or >S, wherein R of >NR is substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or Unsubstituted alkyl or substituted or unsubstituted cycloalkyl, wherein R in >Si(-R) ₂ is hydrogen, optionally substituted aryl, optionally substituted alkyl or optionally substituted cycloalkyl, and a linking group In addition, at least one of R in the >NR and >Si(-R) ₂ is a linking group or a single bond in the group consisting of the A ring, the B ring, R ^XC and R ^A may be bonded to at least one selected

r is an integer from 1 to 4;

Each R ^A is independently hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and any R ^A may be bonded to another arbitrary R ^A through a linking group or a single bond.

As an example of said substituent, the substituent represented by any one of the following is mentioned.

In each formula, what is necessary is just to couple|bond with two or three consecutive (adjacent) atoms in the ring of any one of the aryl ring or heteroaryl ring in *.

<Cycloalkane Condensation>

At least one selected from the group consisting of an aryl ring and a heteroaryl ring in the polyaromatic compound represented by Formula (1) may be condensed with at least one cycloalkane. The polyaromatic compound represented by formula (1B) is also the same, and the following description applies similarly to the polyaromatic compound represented by any one of these formulas.

As the cycloalkane, a cycloalkane having 3 to 24 carbon atoms may be used. At least one hydrogen in the cycloalkane at this time may be substituted with an aryl of 6 to 30 carbon atoms, a heteroaryl of 2 to 30 carbon atoms, an alkyl of 1 to 24 carbon atoms, or a cycloalkyl of 3 to 24 carbon atoms, and At least one -CH ₂ - in the cycloalkane may be substituted with -O-.

Cycloalkane is a cycloalkane having 3 to 20 carbon atoms, and at least one hydrogen in the cycloalkane is aryl having 6 to 16 carbon atoms, heteroaryl having 2 to 22 carbon atoms, alkyl having 1 to 12 carbon atoms, or carbon atoms 3 to 16. It is preferable that it is a cycloalkane which may be substituted by 16-cycloalkyl.

Examples of "cycloalkanes" include cycloalkanes having 3 to 24 carbon atoms, cycloalkanes having 3 to 20 carbon atoms, cycloalkanes having 3 to 16 carbon atoms, cycloalkanes having 3 to 14 carbon atoms, cycloalkanes having 5 to 10 carbon atoms, and cycloalkanes having 5 to 8 carbon atoms. cycloalkanes, cycloalkanes having 5 to 6 carbon atoms, cycloalkanes having 5 carbon atoms, and the like.

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

Among the above examples, at least one carbon at the α position of a cycloalkane (the carbon at a position adjacent to the carbon at the condensation site in a cycloalkyl condensed to an aryl ring or a heteroaryl ring) as shown in the following structural formula, for example. A structure having a substituent of is preferable, a structure having two substituents on the α-position carbon is more preferable, and a structure in which both of the two α-position carbons have two substituents (having a total of four substituents) more preferable than As this substituent, C1-C5 alkyl (especially methyl), halogen (especially fluorine), heavy hydrogen, etc. are mentioned. In particular, it is preferable to have a structure in which a partial structure represented by the following formula (B) is bonded to an adjacent carbon atom in an aryl ring or heteroaryl ring.

In Formula (B), * represents a bonding position.

The number of cycloalkanes condensed to one aryl ring or heteroaryl ring is preferably 1 to 3, more preferably 1 or 2, still more preferably 1. Examples of condensation of one benzene ring (phenyl) with one or more cycloalkanes are shown below. * represents a bonding position, and the position may be any of carbons constituting a benzene ring and not constituting a cycloalkane. Condensed cycloalkanes may condense as shown in formulas (Cy-1-4) and (Cy-2-4). The same applies even when the ring (group) to be condensed is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), and even when the cycloalkane to be condensed is a cycloalkane other than cyclopentane or cyclohexane.

At least one -CH ₂ - in the cycloalkane may be substituted with -O-. For example, an example in which one or a plurality of -CH ₂ - in a cycloalkane condensed to one benzene ring (phenyl) is substituted with -O- is shown below. The same applies even when the ring (group) to be condensed is an aryl ring or heteroaryl ring other than a benzene ring (phenyl), and even when the cycloalkane to be condensed is a cycloalkane other than cyclopentane or cyclohexane.

Cycloalkane may be substituted with at least one substituent, and any substituent selected from the substituent group Z can be mentioned as this substituent. Among these substituents, alkyl (eg, alkyl having 1 to 6 carbon atoms) and cycloalkyl (eg, cycloalkyl having 3 to 14 carbon atoms) are preferable. It is also preferable that either hydrogen is substituted with halogen (for example, fluorine) or heavy hydrogen. In addition, when cycloalkyl is substituted, the substitution form which forms a spiro structure may be sufficient, For example, the example in which the spiro structure was formed in the cycloalkane condensed to one benzene ring (phenyl) is shown below. * in each structural formula means a benzene ring contained in the skeleton structure of a compound in the case of a benzene ring, and means a bond substituted in the skeleton structure of a compound in the case of phenyl.

As a form of cycloalkane condensation, first, the aryl ring and heteroaryl ring in each of the A ring, B ring, D ring, E ring, F ring and G ring in the polycyclic aromatic compound represented by formula (1) are cyclo A form condensed with an alkane may be mentioned.

As another form of cycloalkane condensation, the polyaromatic compound represented by formula (1) is, for example, >NR ^NX , where R ^NX is an aryl condensed with a cycloalkane, and diarylamino condensed with a cycloalkane (this aryl moiety condensed with), carbazolyl condensed with cycloalkane (condensed with this benzene ring moiety), or benzocarbazolyl condensed with cycloalkane (condensed with this benzene ring moiety).

In addition, by introducing a cycloalkane structure into the polyaromatic compound represented by formula (1), further lowering of the melting point and sublimation temperature can be expected. This means that thermal decomposition of the material can be avoided because it can be purified at a relatively low temperature in sublimation purification, which is almost indispensable as a method for purifying materials for organic devices such as organic EL elements requiring high purity. In addition, this also applies to the vacuum deposition process, which is an effective means for manufacturing organic devices such as organic EL elements, and since the process can be carried out at a relatively low temperature, thermal decomposition of materials can be avoided and, as a result, high-performance organic devices can be obtained. can In addition, since the introduction of the cycloalkane structure improves the solubility in organic solvents, it becomes possible to apply it to device fabrication using a coating process. However, the present invention is not particularly limited to this principle.

<Substitution with heavy hydrogen, cyano or halogen>

Deuterium, cyano, or halogen may be sufficient as all or part of hydrogen in the structure represented by Formula (1). The same applies to the structure represented by formula (1B), so the following description applies to the polyaromatic compound represented by formula (1B) as well.

For example, in the structure represented by formula (1), the aryl ring or heteroaryl ring in the A ring, B ring, D ring, E ring, F ring and G ring, and the aryl in the A to G ring A ring or a substituent of a heteroaryl ring, and when X is >NR ^NX , >C(-R ^CX ) ₂ , or >Si(-R ^IX ) ₂ , R ^NX , R ^CX or R ^IX (=alkyl, cycloalkyl , aryl, or heteroaryl) may be substituted with deuterium, cyano or halogen, among which all or part of the hydrogen in aryl or heteroaryl is substituted with deuterium, cyano or halogen. can be heard Halogen is fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine, more preferably fluorine or chlorine, and still more preferably fluorine. Moreover, it is also preferable that all or part of the hydrogen in the structure represented by Formula (1) is deuterated from a durable viewpoint.

<Specific examples of polyaromatic compounds represented by formula (1)>

Examples of polyaromatic compounds represented by formula (1) include compounds represented by any one of the following structural formulas.

1-1-2. high molecular weight polycyclic aromatic compound

The emitting dopant included in the light emitting layer of the organic electroluminescent device of the present invention is a polymer compound obtained by polymerizing a reactive compound having a reactive substituent substituted thereon in addition to the polycyclic aromatic compound represented by Formula (1) as a monomer (this polymer compound The monomer for obtaining has a polymerizable substituent), or a polymer crosslinked product obtained by further crosslinking the polymer compound (the polymer compound for obtaining the polymer crosslinked product has a crosslinkable substituent), or a main chain polymer and A pendant-type polymer compound obtained by reacting the above-mentioned reactive compound (the reactive compound for obtaining the pendant-type polymer compound has a reactive substituent), or a pendant-type polymer crosslinked product obtained by further crosslinking the pendant-type polymer compound (this pendant-type polymer cross-linked compound) The pendant type high molecular compound for obtaining the sieve may have a crosslinkable substituent).

On the other hand, in the present specification, a "polymer compound" means a polymer having a molecular weight distribution and having a number average molecular weight in terms of polystyrene of 1x10 ³ to 1x10 ⁸ (1x10^3 to 1x10^8). The number average molecular weight (Mn) of the polymer compound in terms of polystyrene can be obtained by size exclusion chromatography (SEC) using tetrahydrofuran as a mobile phase. Specifically, the polymer compound to be measured is dissolved in tetrahydrofuran at a concentration of about 0.05% by mass, and 10 µL is injected into SEC. The flow rate of the mobile phase was 1.0 mL/min, and PLgelMIXED_B (manufactured by Polymer Laboratories) was used as the column. As the detector, a UV_VIS detector (Toso, trade name: UV-8320GPC) can be used.

The polymer compound preferably has a number average molecular weight of 2000 to 1x10 ⁸ , more preferably 5000 to 1x10 ⁸ .

As the above-mentioned reactive substituent (including the polymerizable substituent, the crosslinkable substituent, and a reactive substituent for obtaining a pendant-type polymer, hereinafter also simply referred to as "reactive substituent"), the polycyclic aromatic compound can be made high in molecular weight. It is not particularly limited as long as it has a substituent, a substituent capable of further crosslinking the polymer compound thus obtained, and a substituent capable of pendant reaction with the main chain polymer, but a substituent having the following structure is preferable. * in each structural formula represents a bonding position.

L is, each independently, a single bond, -O-, -S-, >C=O, -O-C(=O)-, C1-C12 alkylene, C1-C12 oxyalkylene, and C1 It is a polyoxyalkylene of ~12. Among the above substituents, a group represented by formula (XLS-1), formula (XLS-2), formula (XLS-3), formula (XLS-9), formula (XLS-10) or formula (XLS-17) is preferable. and a group represented by formula (XLS-1), formula (XLS-3) or formula (XLS-17) is more preferred.

These high molecular compounds, crosslinked polymers, pendant type high molecular compounds, and crosslinked pendant type polymers, in addition to repeating units of polycyclic aromatic compounds represented by formula (1), substituted or unsubstituted triarylamines, substituted or unsubstituted Fluorene, substituted or unsubstituted anthracene, substituted or unsubstituted tetracene, substituted or unsubstituted triazine, substituted or unsubstituted carbazole, substituted or unsubstituted tetraphenylsilane, substituted or unsubstituted spiro flu At least one selected from the group consisting of orene, substituted or unsubstituted triphenylphosphine, substituted or unsubstituted dibenzothiophene, and substituted or unsubstituted dibenzofuran may be included as a repeating unit.

As a substituent in these repeating units, for example, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (two aryls may be bonded through a single bond or a linking group ), alkyl, cycloalkyl, alkoxy, aryloxy, triarylsilyl, trialkylsilyl, tricycloalkylsilyl, dialkylcycloalkylsilyl, or alkyldicycloalkylsilyl. The "aryl" of triarylamine and the details of these substituents can be cited from the description of the polycyclic aromatic compound represented by Formula (1).

The details of the uses of these polymer compounds, crosslinked polymers, pendant type polymer compounds and pendant type polymer compounds (hereinafter, simply referred to as "polymer compounds and crosslinked polymers") will be described later.

1-1-3. polycyclic aromatic Method for preparing the compound

The polyaromatic compound represented by formula (1) is basically a condensed ring containing c ring, F ring (f ring) and G ring (g ring), A ring (a ring), and B ring (b ring). ), by combining D ring (d ring) and E ring (e ring) with a linking group (group containing X) and a single bond to prepare an intermediate (first reaction), then A ring (a ring), A final product can be produced by bonding condensed rings including B ring (b ring), c ring, D ring (d ring) and E ring (e ring) with boron (second reaction). In the first reaction, for example, in the case of an etherification reaction, a general reaction such as a nucleophilic substitution reaction or a Ullman reaction can be used, and in the case of an amination reaction, a general reaction such as a Birchwald-Hartwig reaction, a nucleophilic substitution reaction, or a Goldberg amination is available. In addition, in the second reaction, a tandem hetero Friedel Crafts reaction (continuous aromatic electron transfer reaction, hereinafter the same) can be used.

As shown in the following schemes (1) and (2), the second reaction is the A ring (a ring), B ring (b ring), c ring, D ring (d ring) and E ring (e ring). It is a reaction that introduces boron that binds condensed rings containing First, a halogen atom between X and a nitrogen atom is halogen-metal exchanged with n-butyllithium, sec-butyllithium or t-butyllithium. Then, boron trichloride, boron tribromide, etc. are added to perform metal exchange of lithium-boron, and then a Bronsted base such as N,N-diisopropylethylamine is added to carry out a tandem Bora Friedel Crafts reaction. , the target can be obtained. In the second reaction, a Lewis acid such as aluminum trichloride may be added to promote the reaction. On the other hand, the halogen atom represented by Cl in the formula may be any of Cl, Br, and I, and can be appropriately selected in consideration of the reactivity of the substrate.

A polyaromatic compound having a substituent at a desired position can be synthesized by appropriately selecting the raw material to be used.

Specific examples of the solvent used in the above reaction are t-butyl benzene, xylene, and the like.

In addition, in the above scheme, before adding boron trichloride, boron tribromide, etc., halogen atoms between X and nitrogen atoms are exchanged for halogen-metals with butyl lithium or the like, An example of a synthesis method in which a tandem hetero Friedel Crafts reaction is performed has been presented. , The reaction can also proceed by adding boron trichloride or boron tribromide as a precursor in which halogen is hydrogen.

On the other hand, as the orthometallization reagent used in the above schemes (1) and (2), alkyl lithium such as methyl lithium, n-butyl lithium, sec-butyl lithium and t-butyl lithium, lithium diisopropylamide, lithium tetra and organic alkali metal compounds such as methylpiperidide, lithium hexamethyldisilazide, and potassium hexamethyldisilazide.

On the other hand, as the metal-boron metal exchange reagent used in the above schemes (1) and (2), boron halides such as boron trifluoride, boron trichloride, boron tribromide and boron triiodide, alkoxides of boron, and boron aryl oxides of , and the like.

Examples of the Bronsted base used in the schemes (1) and (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 , Ar ₄ BNa, Ar ₄ BK, Ar ₃ B, Ar ₄ Si (where Ar is aryl such as phenyl), and the like.

Examples of Lewis acids used in schemes (1) and (2) include AlCl ₃ , AlBr ₃ , AlF ₃ , BF ₃ OEt ₂ , BCl ₃ , BBr ₃ , BI ₃ , GaCl ₃ , GaBr ₃ , InCl ₃ , InBr ₃ , In(OTf) ₃ , SnCl ₄ , SnBr ₄ , AgOTf, ScCl ₃ , Sc(OTf) ₃ , ZnCl ₂ , ZnBr ₂ , Zn(OTf) ₂ , MgCl ₂ , MgBr ₂ , Mg(OTf) ₂ , LiOTf , NaOTf, KOTf, Me ₃ SiOTf, Cu(OTf) ₂ , CuCl ₂ , YCl ₃ , Y(OTf) ₃ , TiCl ₄ , TiBr ₄ , ZrCl ₄ , ZrBr ₄ , FeCl ₃ , FeBr ₃ , CoCl ₃ , CoBr ₃ etc. can be mentioned.

In the above schemes (1) and (2), a Bronsted base or a Lewis acid may be used to promote the tandem hetero Friedel Crafts reaction. However, when boron halides such as boron trifluoride, boron trichloride, boron tribromide, and boron triiodide are used, along with the progress of the aromatic electron transfer reaction, acids such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide The use of Bronsted bases to capture acids is effective. On the other hand, when an aminated halide of boron or an alkoxide of boron is used, amines and alcohols are formed as the aromatic electron transfer reaction progresses, so in most cases it is not necessary to use a Bronsted base, Since the ability of amino or alkoxy to leave is low, it is effective to use a Lewis acid that promotes the detachment.

Further, polycyclic aromatic compounds represented by formula (1) include those in which at least part of the hydrogen atoms are substituted with deuterium and those in which halogens such as fluorine and chlorine are substituted. In these compounds, the desired position is deuterated or fluorinated. Alternatively, it can be synthesized in the same manner as above by using a chlorinated raw material.

1-2. host material ( hole transport host material and electron transport host material)

The light emitting layer of the organic electroluminescent device of the present invention includes an emitting dopant, and at least two materials selected from the group consisting of a hole transporting host material, an electron transporting host material, and an assisting dopant material. That is, the light emitting layer contains at least one of a hole-transporting host material and an electron-transporting host material. The light emitting layer preferably contains both a hole-transporting host material and an electron-transporting host material.

The hole-transporting host material (HH) and the electron-transporting host material (EH) satisfy the following relationship with respect to HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital).

The HOMO of the hole-transporting host material (HH) is shallower than the HOMO of the electron-transporting host material (EH), and the LUMO of the electron-transporting host material (EH) is deeper than the LUMO of the hole-transporting host material (HH).

In addition, it is preferable that the HOMO of the emitting dopant is shallower than the HOMO of the hole transporting host material (HH), or the LUMO of the emitting dopant is deeper than the LUMO of the electron transporting host material (EH).

In addition, the lowest excitation triplet energy level (ET1) of the hole-transporting host material (HH) and the electron-transporting host material (EH) is the highest in the light-emitting layer from the viewpoint of promoting, without hindering, the generation of TADF in the light-emitting layer. It is preferable that the E _T1 of the emitting dopant or the assisting dopant having E _T1 be higher than that of the E T1 , and specifically, the E _T1 of the host material is 0.01eV or more higher than the E _T1 of the emitting dopant or the assisting dopant. It is preferably, more preferably higher than 0.03 eV, more preferably higher than 0.1 eV. Further, E _T1 of the host material is preferably 2.47 eV or higher, more preferably 2.49 eV or higher, and still more preferably 2.56 eV or higher.

It is also preferable to use a hole-transporting host material for the hole-transporting layer adjacent to the light-emitting layer, and to use an electron-transporting host material for the electron-transporting layer adjacent to the light-emitting layer. This is because carrier leakage and energy leakage from the light emitting layer to the adjacent layer are less likely to occur, and a highly efficient organic EL element can be obtained. The host material (hole-transporting host material) in the light-emitting layer and the hole-transporting layer material may be the same or different. In addition, the host material (electron-transporting host material) in the light-emitting layer and the material of the electron-transporting layer may be the same or different.

[Hole-transporting host material (HH)]

As an example of a preferable hole-transporting host material (HH), it is represented by the formula (HH-1) or has a partial structure represented by the formula (HH-1) and is selected from the group consisting of an aryl ring and a heteroaryl ring, at least Compounds having a structure containing three rings are exemplified. It is preferable that this compound contains neither an imine structure (-N=C-; partial structure of a heteroaryl ring), boron (>B-), nor cyano (CN).

In formula (HH-1),

Q is >O, >S, or >NA ^H ;

One carbon atom next to the carbon atom to which Q is bonded in each of the two phenyls in the formula (HH-1) may be bonded to each other by L,

L is a single bond, >O, >S, or >C(-A ^H ) ₂ ,

A ^H is hydrogen, aryl, or heteroaryl, and two A ^Hs in >C(-A ^H ) ₂ may be bonded to each other.

When the hole-transporting host material contains the structure represented by formula (HH-1) as a partial structure, it may contain one partial structure, but it is also preferable to include two or more of these partial structures. When two or more are included, the two or more partial structures may be the same as or different from each other. Two or more partial structures may be bonded to each other by a single bond, may be bonded by sharing an arbitrary ring included in the partial structure, or may be bonded by condensing arbitrary rings included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

The compound represented by the formula (HH-1) or having a partial structure represented by the formula (HH-1) has a structure containing at least three rings selected from the group consisting of an aryl ring and a heteroaryl ring. have It is preferable that it is 6 or more, and, as for the number of rings contained, it is more preferable that it is 8 or more. Moreover, it is preferable that it is 20 or less, it is more preferable that it is 15 or less, and it is still more preferable that it is 10 or less. The number of rings means the number as a single ring, and about a condensed ring, let it be the number which counted the single rings which comprise a condensed ring.

The hole-transporting host material contains at least one partial structure selected from the group consisting of a triarylamine structure, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a condensed polycyclic ring including phenoxazine or phenothiazine. It is preferable that it is a compound which does. The hole-transporting host material may contain one such partial structure, but it is also preferable to include two or more. When two or more are included, the two or more partial structures may be the same as or different from each other.

Specific examples of the hole-transporting host material include the following compounds.

Among the above, HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1-20 to HH-1-24 , HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, HH-1-106 to HH-1-108 and HH-1-109 to HH -1-113 is preferred.

[Electron transport host material (EH)]

As an example of the electron transporting host material (EH),

At least one selected from the group consisting of an aryl ring and a heteroaryl ring having a partial structure represented by formulas (EH-1A) to (EH-1D) or formulas (EH-1A) to (EH-1D); Compounds having a structure containing three rings are exemplified.

In the formulas (EH-1A) to (EH-1D),

Ar is a heteroaryl ring containing N = C as a partial structure constituting the ring,

Z is a single bond, -O-, -S-, or -N(-A ^E )-;

The carbon atom adjacent to the carbon atom to which Z is bonded and A ^E to which Z is bonded may be bonded to each other by L,

L is a single bond, >O, >S or >C(-A ^E ) ₂ ;

A ^E is aryl, heteroaryl, or triarylsilyl, and two A ^E in >C(-A ^E ) ₂ may be bonded to each other;

X is C, P or S;

When X is C, n = 2, m = 1,

When X is P, n = 3, m = 1,

When X is S, n = 2 and m = 1 to 2.

Compounds represented by the formulas (EH-1A) to (EH-1D) or having partial structures represented by formulas (EH-1A) to (EH-1D) are selected from the group consisting of aryl rings and heteroaryl rings It has a structure containing at least three rings. The number of rings contained is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more. Moreover, it is preferable that it is 20 or less, it is more preferable that it is 15 or less, and it is still more preferable that it is 10 or less. The number of rings means the number as a single ring, and about a condensed ring, let it be the number which counted the single rings which comprise a condensed ring.

When the electron-transporting host material contains structures represented by formulas (EH-1A) to (EH-1D) as partial structures, it may contain one partial structure, but it is also preferable to include two or more of these partial structures. When two or more are included, the two or more partial structures may be the same as or different from each other. Two or more partial structures may be bonded to each other by a single bond, may be bonded by sharing an arbitrary ring included in the partial structure, or may be bonded by condensing arbitrary rings included in the partial structure. The partial structure may further have a substituent selected from aryl, heteroaryl, diarylamino, or aryloxy.

Specific examples of the electron-transporting host material include the following compounds.

As another preferable example of the electron-transporting host material (a compound having a partial structure represented by formula (EH-1)), a polycyclic aromatic compound represented by the following formula (EH-1b) or a compound represented by the following formula (EH-1b) Polymers of polycyclic aromatic compounds having a plurality of supporting structures are exemplified.

In formula (EH-1b),

R ¹ , R ² , R ³ , R ⁴ and R ⁵ (hereinafter also referred to as “R ¹ etc.”) are each independently hydrogen or a substituent. This substituent may be selected from the substituent group Z.

In Formula (EH-1b), X ¹ and X ² are each independently >NR (amine nitrogen), >O, >C(-R) ₂ , >S or >Se, and X ¹ and X ² together does not result in >C(-R) ₂ ,

R in >NR and >C(-R) ₂ is each independently hydrogen or a substituent selected from substituent group Z, and further selected from aryl, heteroaryl, alkyl or cycloalkyl (above, second substituent) It may be substituted, and each R in >NR and >C(-R) ₂ may be independently bonded to at least one of the a, b, and c rings via a linking group or a single bond.

Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ (hereinafter also referred to as “Y ¹ etc.”) are each independently =C(-R)- or =N- (pyridinous nitrogen) , and at least one is =N-(pyridinic nitrogen).

R in =C(-R)- above is each independently hydrogen or a substituent selected from substituent group Z.

Adjacent groups among R ¹ , R ² , R ³ , R ⁴ and R ⁵ , and R in =C(-R)- as Y ¹ to Y ⁶ are bonded to each other to form ring a, ring b and ring c may form an aryl ring or heteroaryl ring together with at least one of the rings, and at least one hydrogen in the formed ring is aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diaryl It may be substituted with boryl (two aryls may be bonded through a single bond or a linking group), alkyl, cycloalkyl, alkoxy, or aryloxy (above, first substituent), and at least one hydrogen in these may be aryl , heteroaryl, alkyl or cycloalkyl (above, the second substituent) may be further substituted.

At least one hydrogen in the compound and structure represented by formula (EH-1b) may be substituted with cyano, halogen or deuterium.

In the formula (EH-1b), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are all hydrogen, or both R ³ and R ⁴ are hydrogen, and R ¹ , R ² and R ⁵ are also It is preferable that at least one selected from the group consisting of substituents other than hydrogen, and the other being hydrogen. As the substituent, aryl which may be substituted with alkyl, alkyl or heteroaryl, heteroaryl which may be substituted with alkyl or aryl, or diarylamino which may be substituted with alkyl or aryl is preferable. At this time, the alkyl is preferably an alkyl having 1 to 6 carbon atoms (methyl, t-butyl, etc.), the aryl is preferably phenyl or biphenyl, and the heteroaryl is triazinyl, carbazolyl (2-carbazolyl , 3-carbazolyl, 9-carbazolyl, etc.), pyrimidinyl, pyridinyl, dibenzofuranyl or dibenzothienyl are preferred. Specific examples include phenyl, biphenyl, diphenyltriazinyl, carbazolyltriazinyl, monophenylpyrimidinyl, diphenylpyrimidinyl, carbazolyltriazinyl, pyridinyl, dibenzofuranyl and dibenzothienyl. can be heard

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

Further, in addition to the arrangement relationship of =N- above, it is preferable that X ¹ and X ² are >0, and a polycyclic aromatic compound containing a partial structure represented by any one of the following formulas is preferable.

In particular, a polycyclic aromatic compound having a partial structure represented by formula (EH-1b-N1) has higher E _S1 , higher E _T1 , and smaller ΔE _S1T1 than a structure without N.

Specific examples of the polycyclic aromatic compound represented by formula (EH-1b) are shown below.

Among the above, EH-1-1 to EH-1-4, EH-1-10, EH-1-21 to EH-1-25, EH-1-32, EH-1-33, EH-1-51 ~EH-1-59, EH-1-61, EH-1-66, EH-1-68, EH-1-71, EH-1-72, EH-1-90, EH-1-94~EH -1-98, EH-1-100, EH-1-101, EH-1-104, EH-1-115, EH-1-117, EH-1-120, EH-1-122, EH-1 -123, EH-1-127 to EH-1-130 are preferable.

[Combination of hole-transporting host material and electron-transporting host material]

A combination of the hole-transporting host material and the electron-transporting host material is selected according to the HOMO, LUMO, and lowest excitation triplet energy level (E _T1 ) of the hole-transporting host material, the electron-transporting host material, and the dopant material.

Regarding HOMO and LUMO, the HOMO (HH) of the hole-transporting host material is shallower than the HOMO (EH) of the electron-transporting host material, and the LUMO (EH) of the electron-transporting host material is deeper than the LUMO (HH) of the hole-transporting host material. Select a combination, more specifically, a combination in which HOMO(HH) is 0.10 eV or more shallower than HOMO(EH), LUMO(HH) is 0.10 eV or more deeper than HOMO(EH), and HOMO(HH) is HOMO A combination in which 0.20eV or more shallow than (EH), LUMO(HH) is 0.20eV or more deeper than HOMO(EH) is more preferable, HOMO(HH) is 0.25eV or more shallower than HOMO(EH), and LUMO(HH) is HOMO A combination at least 0.25 eV deeper than (EH) is more preferable.

The hole-transporting host material and the electron-transporting host material may be a combination that forms an association called an exciplex. It is generally known that exciplex is easy to form between a material having a relatively deep LUMO level and a material having a shallow HOMO level. The interaction of the hole-transporting host material and the electron-transporting host material, specifically, whether or not an exciplex is formed is determined by forming a monolayer film composed of the hole-transporting host material and the electron-transporting host material under the same conditions as the formation conditions of the light emitting layer, and emitting light. It can be judged by measuring the spectrum (fluorescence and phosphorescence spectrum) and comparing the obtained emission spectrum with the emission spectrum exhibited by each of the hole-transporting host material and the electron-transporting host material alone. It can be judged that the spectrum of the mixed film containing the hole-transporting host material and the electron-transporting host material exhibits an emission wavelength different from both the film spectrum of the hole-transporting host material and the film spectrum of the electron-transporting host material. Specifically, the index may be that the peak wavelengths of the spectra differ by 10 nm or more.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material that do not form an exciplex include the following combinations. In order to satisfy the above physical property values of HOMO, LUMO and E _T1 , in the hole transporting host material, carbazole, dibenzofuran, dibenzothiophene, triarylamine, indolocarbazole and benzoxazinophenoxazine are partially used. A compound having as a structure is preferable, a compound having carbazole, dibenzofuran and dibenzothiophene as a partial structure is more preferable, and a compound having carbazole as a partial structure is even more preferable. Similarly, for the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide, benzofuropyridine and dibenzoxacillin as partial structures are preferred, and triazine, phosphine oxide, benzofuropyridine and dibenzooxa A compound having silin as a partial structure is more preferred, and a compound having triazine is even more preferred.

More specifically, the hole transporting host material is HH-1-1, HH-1-2, HH-1-4 to HH-1-12, HH-1-17, HH-1-18, HH-1 -20 to HH-1-24, HH-1-82, HH-1-84 to HH-1-89, HH-1-91, HH-1-92, and HH-1-106 to HH-1- It is preferably selected from the group consisting of 108, and the electron transporting host material is EH-1-1 to EH-1-4, EH-1-10, EH-1-21 to EH-1-25, EH-1 -32, EH-1-33, EH-1-51~EH-1-59, EH-1-61, EH-1-71, EH-1-72, EH-1-90, EH-1-94 , EH-1-100, EH-1-101, EH-1-104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127~ It is preferably selected from the group consisting of EH-1-130. Preferable examples of combinations include compound HH-1-1 and compound EH-1-22, compound HH-1-1 and compound EH-1-23, compound HH-1-1 and compound EH-1-24, compound HH- 1-2 and compound EH-1-22, compound HH-1-2 and compound EH-1-23, compound HH-1-2 and compound EH-1-24, or compound HH-1-1 and compound EH- 1-128 may be cited.

Specific examples of combinations of a hole-transporting host material and an electron-transporting host material forming an exciplex include the following combinations. In order to satisfy the above physical property values of HOMO, LUMO and E _T1 , compounds having carbazole, triarylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are preferred for the hole-transporting host material. Compounds having arylamine, indolocarbazole and benzoxazinophenoxazine as partial structures are more preferred, and compounds having triarylamine as partial structures are even more preferred. Similarly, in the electron-transporting host material, compounds having pyridine, triazine, phosphine oxide, and benzofuropyridine as partial structures are preferred, and triazine, phosphine oxide, benzofuropyridine, and dibenzoxacillin as partial structures. Compounds having phosphine oxide and triazine are more preferred.

More specifically, the hole transporting host material is HH-1-1, HH-1-2, HH-1-11, HH-1-12, HH-1-17, HH-1-18, HH-1 It is preferably selected from the group consisting of -23 and HH-1-24, and the electron transporting host material is EH-1-1 to EH-1-4, EH-1-21 to EH-1-25, EH- 1-51 to EH-1-57, EH-1-59, EH-1-66, EH-1-68, EH-1-90, EH-1-100, EH-1-101, EH-1- 104, EH-1-117, EH-1-120, EH-1-122, EH-1-123, and EH-1-127 to EH-1-130.

Preferable examples of combinations include compound HH-1-1 and compound EH-1-21, compound HH-1-2 and compound EH-1-21, compound HH-1-12 and compound EH-1-94, compound HH- 1-12 and compound EH-1-117, compound HH-1-1 and compound EH-1-130, compound HH-1-33 and compound EH-1-117, compound HH-1-48 and compound EH-1 -117 or compound HH-1-49 and compound EH-1-117.

In addition, for specific combinations of hole-transporting host materials and electron-transporting host materials, Organic Electronics 66 (2019) 227-24, Advanced.Functional Materals 25 (2015) 361-366., Advanced Materials 26 (2014) 4730- 4734., ACS Applied Materials and Interfaces 8 (2016) 32984-32991., ACS Applied Materials and Interfaces 2016, 8, 9806-9810, ACS Applied Materials and Interfaces 2016, 8, 32984-32991, Journal of Materials Chemisty C, 2018 , 6, 8784-8792, Angewante Chemie International Edition. 2018, 57, 12380-12384, Advanced Functional Materials, 24, 2014, 3970, Advanced Materials, 26, 2014, 5684, and Synthetic Metals, 201, 2015, 49 may be referred to.

1-3. assisting dopant ( heat activated delayed phosphor or phosphorescent material)

The light emitting layer preferably contains an assisting dopant together with an emitting dopant and a host material. As the assisting dopant, a thermally activated delayed phosphor or phosphorescent material is preferable.

[Heat activated delayed phosphor]

"Thermally activated delayed phosphor" is a phosphor capable of absorbing thermal energy to cause inverse intersystem crossing from the lowest triplet excited state to the lowest singlet excited state, and radiatively deactivated from the lowest singlet excited state to emit delayed fluorescence. means compound. However, "heat-activated delayed fluorescence" includes those that pass through higher-order triplet in the excitation process from the lowest triplet excited state to the lowest singlet excited state. For example, a paper by Monkmans, Durham University (NATURE COMMUNICATIONS, 7:13680, DOI:10.1038/ncomms 13680), a paper by Hosokai et al. :e1603282), a paper by Kyoto University scholars (Scientific Reports, 7:4820, DOI:10.1038/s41598-017-05007-7), as well as a conference presentation by Kyoto University scholars (Japan Chemical Society 98th Spring Banquet, Publication No.: 2I4-15, Mechanism of Highly Efficient Luminescence in Organic Electroluminescence Using DABNA as Light-Emitting Molecule, Graduate School of Engineering, Kyoto University), Review by Bui et al. (DOI: 10.3762/bjoc.14.18), by Duan et al. review (DOI:10.1063/1.5143501), review by Dings (DOI:10.1088/1674-4926/42/5/050201), and review by Xies (DOI:10.1002/adom.202002204). In the present invention, when the fluorescence lifetime of a sample containing the target compound is measured at 300 K, a slow fluorescence component is observed, and the target compound is determined to be a "heat-activated delayed phosphor". Here, the slow fluorescence component refers to a fluorescence lifetime of 0.1 μsec or more. The fluorescence lifetime can be measured using, for example, a fluorescence lifetime measuring device (C11367-01 manufactured by Hamamatsu Photonics Co., Ltd.).

In the light emitting layer further containing a "heat-activated delayed phosphor" as an assisting dopant, the polycyclic aromatic compound of the present invention can function as an emitting dopant. That is, the "heat-activated delayed phosphor" can function as an assisting dopant that assists light emission of the polycyclic aromatic compound of the present invention.

In this specification, an organic electroluminescent device using a thermally activated delayed phosphor as an assisting dopant is sometimes referred to as a "TAF device" (TADF Assisting Fluorescence device).

The term "host compound" in a TAF element means a compound whose lowest excitation singlet energy level obtained from the shoulder of the short wavelength side of the peak of the fluorescence spectrum is higher than that of the thermally activated delayed phosphor as an assisting dopant and the emitting dopant. do.

FIG. 2 shows an energy level diagram of a light emitting layer of a TAF device using a general fluorescent dopant as an emitting dopant (ED). In the figure, the energy level of the ground state of the host is E(1, G), the lowest excitation singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the host is E(1, S, Sh), and the short wavelength of the phosphorescence spectrum of the host is The lowest excitation triplet energy level obtained from the side shoulder is E(1, T, Sh), the assisting dopant's ground state energy level is E(2, G), and the assisting dopant's fluorescence spectrum is obtained from the short wavelength side's shoulder E(2, S, Sh) for the lowest excitation singlet energy level, E(2, T, Sh) for the lowest excitation triplet energy level obtained from the shoulder on the short wavelength side of the phosphorescence spectrum of the assisting dopant, The ground state energy level is E(3, G), the lowest excitation singlet energy level obtained from the shoulder on the short wavelength side of the fluorescence spectrum of the emitting dopant is E(3, S, Sh), and the phosphorescence spectrum of the emitting dopant is on the short wavelength side The lowest excitation triplet energy level obtained from the shoulder is E(3, T, Sh), the hole is h+, the electron is e-, and the fluorescence resonance energy transfer is FRET (Fluorescence Resonance Energy Transfer). In the TAF device, when a general fluorescent dopant is used as the emitting dopant (ED), energy upconverted from the assisting dopant moves to the lowest excitation singlet energy level E(3, S, Sh) of the assisting dopant and emits light. do. However, some lowest excitation triplet energy level E(2, T, Sh) on the assisting dopant moves to the lowest excitation triplet energy level E(3, T, Sh) of the emitting dopant, or Intersystem crossing occurs from the excitation singlet energy level E(3, S, Sh) to the lowest excitation triplet energy level E(3, T, Sh), and continues to the ground state E(3, G) deactivate with A part of the energy is not used for light emission through this path, and energy is wasted.

In contrast, in the organic EL device of the present embodiment, energy transferred from the assisting dopant to the emitting dopant can be efficiently used for light emission, and thus high light emission efficiency can be realized. This is estimated to be based on the following light emission mechanism.

A preferable energy relationship in the organic electroluminescent device of the present embodiment is shown in FIG. 3 . In the organic electroluminescent device of this embodiment, a compound having a boron atom as an emitter dopant has a high lowest triplet excitation energy level E(3, T, Sh). Because of this, even when the lowest excitation singlet energy upconverted in the assisting dopant crosses intersystem to, for example, the lowest excitation triplet energy level E(3, T, Sh) in the emitting dopant, on the emitting dopant Upconverted or recovered to the lowest excitation triplet energy level E(2, T, Sh) on the assisting dopant (thermally activated delayed phosphor). Therefore, the generated excitation energy can be used for light emission without waste. In addition, by dividing into two types of molecules capable of improving the function of upconversion and light emission, respectively, it is expected that the residence time of high energy is reduced and the burden on the compound is reduced.

In this embodiment, known host compounds can be used, and examples thereof include compounds having at least one of a carbazole ring and a furan ring, and among them, at least one of furanyl and carbazolyl, and an aryl It is preferable to use a compound in which at least one of ene and heteroarylene is bonded. As a specific example, mCP, mCBP, etc. are mentioned. Further, a compound having TADF activity may be used as the host compound.

The lowest excitation triplet energy level E(1,T,Sh) found from the shoulder of the short wavelength side of the peak of the phosphorescence spectrum of the host compound is the highest in the light emitting layer from the viewpoint of promoting the generation of TADF in the light emitting layer without hindering it. It is preferably higher than the lowest triplet excitation energy levels E(2,T,Sh) and E(3,T,Sh) of an emitting dopant or an assisting dopant having a high lowest excitation triplet energy level, specifically, , The lowest excitation triplet energy level E(1,T,Sh) of the host compound is preferably 0.01 eV or more higher than E(2,T,Sh) and E(3,T,Sh), and is 0.03 eV or more Higher is more preferable, and higher than 0.1eV is still more preferable.

The thermally activated delayed phosphor (TADF compound) used in the TAF element uses an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to achieve HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied It is preferable to be a donor-acceptor type thermally activated delayed phosphor (D-A type TADF compound) designed to localize molecular orbitals and cause efficient reverse intersystem crossing.

Here, in the present specification, "electron-donating substituent" (donor) means a substituent and partial structure in which HOMO is localized in a heat-activated delayed phosphor molecule, and "electron-accepting substituent" (acceptor) means a heat It shall mean the substituent and partial structure in which LUMO is localized in active type delayed phosphor molecule.

In general, a thermally activated delayed phosphor using a donor or acceptor has a large spin-orbit coupling (SOC) due to its structure, and at the same time, the exchange interaction between HOMO and LUMO is small and ΔE _S1T1 is small, so, Very fast inverse interphase crossing velocities are obtained. On the other hand, thermally activated delayed phosphors using a donor or acceptor have a large structural relaxation in the excited state (since the stable structure is different between the ground state and the excited state in some molecules, it is changed from the ground state to the excited state by external stimulation). When conversion occurs, the structure is then changed to a stable structure in an excited state), providing a wide luminescence spectrum, so there is a possibility of reducing color purity when used as a luminescent material.

However, by simultaneously using the polycyclic aromatic compound of the present invention, the polycyclic aromatic compound of the present invention functions as an emitting dopant and the TADF compound functions as an assisting dopant, and high color purity can be obtained. The TADF compound may be any compound whose emission spectrum overlaps at least partially with the absorption spectrum of the polycyclic aromatic compound of the present invention. Both the polycyclic aromatic compound and the TADF material of the present invention may be included in the same layer, or may be included in an adjacent layer or other adjacent layer.

As the thermally activated delayed phosphor in the TAF element, for example, a compound in which a donor and an acceptor are bonded directly or through a spacer can be used. As the electron-donating group (donor structure) and electron-accepting group (acceptor structure) used in the thermally activated delayed phosphor of the present invention, for example, the structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used As the donor structure, carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, Phenylbicarbazole, bicarbazole, tercarbazole, diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis (tert-butylphenyl)amine, N1-(4-(diphenylamino)phenyl)-N4,N4-diphenylbenzene-1,4-diamine, dimethyltetraphenyldihydroacridinediamine, tetramethyl-dihydroinde Noacridine, diphenyldihydrodibenzoazacillin, etc. are mentioned. As the acceptor structure, sulfonyldibenzene, benzophenone, phenylenebis (phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole , oxazole, thiadiazole, benzothiazole, benzobis(thiazole), benzoxazole, benzobis(oxazole), quinoline, benzoimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide , dimethylanthracenone, anthracenedione, 5H-cyclopenta[1,2-b:5,4-b']dipyridine, fluorenedicarbonitrile, triphenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyridine midine, methylpyrimidine, pyridinedicarbonitrile, dibenzoquinoxalinedicarbonitrile, bis(phenylsulfonyl)benzene, dimethylthioxanthenedioxide, thianthrenetetraoxide and tris(dimethylphenyl)borane. In particular, the compound having thermally activated delayed fluorescence in the TAF element has, as a partial structure, carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isop It is preferably a compound having at least one selected from talonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole and benzophenone.

The compound used as the assisting dopant of the light emitting layer in the TAF element is a thermally activated delayed phosphor, and it is preferable that the emission spectrum overlaps at least partially with the absorption peak of the emitting dopant.

[Phosphorescent material (assisting dopant)]

In the light emitting layer, you may use a phosphorescent material as an assisting dopant. Phosphorescent materials utilize intramolecular spin-orbit interactions (heavy atom effect) by metal atoms to obtain light emission from excited triplet states. As such a phosphorescent material, a luminescent metal complex can be used, for example. Examples of the luminescent metal complex include compounds represented by the following formula (B-1) and the following formula (B-2).

In formula (B-1), M is at least one selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu, n is an integer of 1 to 3, and "X-Y" are each independently a bidentate ligand.

In formula (B-2), M is at least one selected from the group consisting of Pt, Re and Cu, and "W-X-Y-Z" is a tetradentate ligand.

In the formula (B-1), from the viewpoint of efficiency and lifetime, M is preferably Ir, and n is preferably 3.

In Formula (B-2), M is preferably Pt from the viewpoint of efficiency and lifetime.

The ligand (X-Y) in the formula (B-1) has at least one ligand selected from the group consisting of the following. The ligand (W-X-Y-Z) in the formula (B-2) has at least one ligand selected from the group consisting of the following as a part.

during the ceremony,

--- in combination with the central metal M,

Y is, each independently, BR _e , NR _e , PR _e , O, S, Se, C=O, S=O, SO2, CR _e R _f , SiR _e R _f , or GeR _e R _f ;

Aromatic carbons C-H in the ring may each independently be substituted with N,

R _e and R _f may be optionally condensed or bonded to form a ring,

R _a , R _b , R _c , and R _d may each independently be unsubstituted or substituted by 1 to the maximum number of substitutions;

R _a , R _b , R _c , R _d , R _e , and R _f are each, independently, hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, alkoxy, aryloxy, amino, silyl, alkenyl , cycloalkenyl, heteroalkenyl, aryl, heteroaryl, nitrile, isonitrile, sulfanyl, or a combination thereof,

However, arbitrary two adjacent substituents in R _a , R _b , R _c , and R _d may form a ring by condensation or bonding, or may form a multidentate ligand.

Examples of the compound represented by formula (B-1) include Ir(ppy) ₃ , Ir(ppy) ₂ (acac), Ir(mppy) ₃ , Ir(PPy) ₂ (m-bppy), BtpIr( acac), Ir(btp) ₂ (acac), Ir(2-phq) ₃ , Hex-Ir(phq) ₃ , Ir(fbi) ₂ (acac), fac-Tris(2-(3-p-xylyl) phenyl)pyridine iridium(III), Eu(dbm) ₃ (Phen), Ir(piq) ₃ , Ir(piq) ₂ (acac), Ir(Fliq) ₂ (acac), Ir(Flq) ₂ (acac), Ru(dtb-bpy) ₃ 2(PF ₆ ), Ir(2-phq) ₃ , Ir(BT) ₂ (acac), Ir(DMP) ₃ , Ir(Mphq) ₃ IR(phq) ₂ tpy, fac -Ir(ppy) ₂ Pc, Ir(dp)PQ ₂ , Ir(Dpm)(Piq) ₂ , Hex-Ir(piq) ₂ (acac), Hex-Ir(piq) ₃ , Ir(dmpq) ₃ , Ir (dmpq) ₂ (acac), FPQIrpic, and the like.

As a compound represented by Formula (B-1), the following compounds are mentioned, for example other than that.

Further, Japanese Unexamined Patent Publication No. 2006-089398, Japanese Unexamined Patent Publication No. 2006-080419, Japanese Unexamined Patent Publication No. 2005-298483, Japanese Unexamined Patent Publication No. 2005-097263, and Japanese Unexamined Patent Publication No. 2004-111379, US Patent Iridium complexes described in the specification of Patent Application Publication No. 2019/0051845, etc., or Advanced Materials, 26:7116-7121, NPG Asia Materials 13, 53 (2021), Applied Physics Letters, 117, 253301 (2020), Light-Emitting Diode- The platinum complex described in An Outlook On the Empirical Features and Its Recent Technological Advancements, Chapter 5 may be used.

1-4. other dopant ingredient

The above-mentioned emitting dopants may be used in combination with other dopant materials. However, the other dopant material is preferably less than 100% by mass, more preferably 50% by mass or less, still more preferably 30% by mass or less, and 10% by mass relative to the total mass of the above-mentioned emitting dopant in one light emitting layer. % or less is particularly preferred. As other dopant materials, known compounds can be used, and various materials can be selected depending on the desired emission color. Specifically, for example, condensed ring derivatives such as phenanthrene, anthracene, pyrene, tetracene, pentacene, perylene, naphthopyrene, dibenzopyrene, rubrene and chrysene, benzoxazole derivatives, and benzothiazole derivatives, benzoimidazole 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, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives (Japanese Patent Laid-Open No. 1-245087), bisstyrylarylene derivatives (Japanese Patent Laid-Open No. 2 -247278), diazaindacene derivatives, furan derivatives, benzofuran derivatives, phenyl isobenzofuran, dimethyl isobenzofuran, di(2-methylphenyl)isobenzofuran, di(2-trifluoromethylphenyl)iso Isobenzofuran derivatives such as benzofuran and phenylisobenzofuran, dibenzofuran derivatives, 7-dialkylaminocoumarin derivatives, 7-piperidinocoumarin derivatives, 7-hydroxycoumarin derivatives, 7-methoxycoumarin derivatives, 7 -Coumarin derivatives such as acetoxycoumarin derivatives, 3-benzothiazolylcoumarin derivatives, 3-benzoimidazolylcoumarin derivatives, and 3-benzooxazolylcoumarin derivatives, dicyanomethylenepyran derivatives, dicyanomethylenethiopyran derivatives, polymethine derivatives, cyanine derivatives, oxobenzoanthracene derivatives, xanthene derivatives, rhodamine derivatives, fluorescein derivatives, pyrylium derivatives, carbostyril derivatives, acridine derivatives, oxazine derivatives, phenylene oxide derivatives, quinacridone derivatives, Quinazoline derivatives, pyrrolopyridine derivatives, furopyridine derivatives, 1,2,5-thiadiazolopyrene derivatives, pyromethene derivatives, perinone derivatives, pyrrolopyrrole derivatives, squarylium derivatives, bioranthrone derivatives, phenazine derivatives, acridone derivatives, deazaflavin derivatives, fluorene derivatives and benzofluorene derivatives, and the like.

As a 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, and Paragraphs 0097 to 0269 of Japanese Patent Application Publication No. 2021-077890 and the like.

2. Organic electric field light emitting element

The organic electroluminescent device of the present invention has a pair of electrodes composed of an anode and a cathode, and a light emitting layer disposed between the pair of electrodes. The organic electroluminescent element may further have another organic layer.

2-1. abandonment electric field Structure of Light-Emitting Device

1 is a schematic cross-sectional view showing an example of an organic EL element.

An organic EL device 100 shown in FIG. 1 includes a substrate 101, an anode 102 provided on the substrate 101, a hole injection layer 103 provided on the anode 102, and a hole injection layer. The hole transport layer 104 provided on 103, the light emitting layer 105 provided on the hole transport layer 104, the electron transport layer 106 provided on the light emitting layer 105, and the electrons provided on the electron transport layer 106 It has an injection layer (107) and a cathode (108) provided on the electron injection layer (107).

In addition, the organic EL element 100 is manufactured by reversing the manufacturing order, for example, the substrate 101, the cathode 108 provided on the substrate 101, and the electron injection layer provided on the cathode 108 ( 107), an electron transport layer 106 provided on the electron injection layer 107, a light emitting layer 105 provided on the electron transport layer 106, a hole transport layer 104 provided on the light emitting layer 105, and a hole transport layer It is good also as a structure which has the hole injection layer 103 provided on (104), and the anode 102 provided on the hole injection layer 103.

It is not necessary to have all of the above layers, and the minimum structural unit is composed of an anode 102, a light emitting layer 105, and a cathode 108, and a hole injection layer 103, a hole transport layer 104, and an electron transport layer 106 ), the electron injection layer 107 is an arbitrarily provided layer. In addition, each said layer may consist of a single layer, respectively, and may consist of multiple layers.

As an aspect of the layer constituting the organic EL element, in addition to the constitutional aspect of the above-described "substrate/anode/hole injection layer/hole transport layer/light emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole transport layer/ Emitting layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/emission layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole injection layer/hole transport layer/emission layer/electron injection layer" / cathode", "substrate/anode/hole injection layer/hole transport layer/emission layer/electron transport layer/cathode", "substrate/anode/emission layer/electron transport layer/electron injection layer/cathode", "substrate/anode/hole transport layer/emission layer" /electron injection layer/cathode", "substrate/anode/hole transport layer/light emitting layer/electron transport layer/cathode", "substrate/anode/hole injection layer/light emitting layer/electron injection layer/cathode", "substrate/anode/hole injection layer" /Light emitting layer/electron transport layer/cathode”, “substrate/anode/light emitting layer/electron transport layer/cathode”, or “substrate/anode/light emitting layer/electron injection layer/cathode” may be used.

The organic EL element may 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 shallower than that of the light emitting layer and a HOMO closer to that of the light emitting layer or the hole transport layer, and is disposed between the light emitting layer and the hole transport layer. Since electrons stay in the light emitting layer and do not leak out to the hole transport layer, shortening of the life due to deterioration of the hole transport layer and decrease in efficiency due to reduction in recombination efficiency can be prevented. The hole blocking layer has a HOMO deeper than that of the light emitting layer and a LUMO close to that of the light emitting layer or the hole transport layer, and is disposed between the light emitting layer and the electron transport layer. Since the holes stay in the light emitting layer and do not leak out to the electron transport layer, shortening of life due to deterioration of the electron transport layer and decrease in efficiency due to 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.

The organic EL element may further have a high T1 layer. The high T1 layer has a higher T1 than the host compound, assisting dopant compound, or emitting dopant compound used in the light emitting layer, and is disposed 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 device, but has a higher T1 than the compound used for the host. By having a high T1 layer around the light emitting layer, the triplet energy is confined and the triplet energy, which normally does not lead to light emission in fluorescent molecules, is converted into singlet energy, so that high efficiency can be obtained. The hole injection/transport layer or the electron blocking layer may serve as the high T1 layer. The electron injection/transport layer or the hole blocking layer may serve as the high T1 layer.

2-2. abandonment electric field radiation in small Board

The substrate 101 is a support for the organic EL element 100, and usually quartz, glass, metal, plastic or the like is used. The substrate 101 is formed in the shape of a plate, film, or sheet depending on the purpose, and for example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like is used. Especially, a glass plate and a board made of transparent synthetic resins, such as polyester, polymethacrylate, polycarbonate, and polysulfone, are preferable. In the case of a glass substrate, soda-lime glass, non-alkali glass, etc. are used, and thickness should just have enough thickness to maintain mechanical strength. In addition, a gas barrier film such as a dense silicon oxide film may be formed on at least one side of the substrate 101 to improve gas barrier properties, and in particular, a plate, film or sheet made of synthetic resin having low gas barrier properties is used as the substrate. When using in (101), it is preferable to form a gas barrier film.

2-3. abandonment electric field radiation in small anode

The anode 102 serves to inject holes into the light emitting layer 105 . Meanwhile, 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 them. do.

Materials forming the anode 102 include inorganic compounds and organic compounds. Examples of the inorganic compound include metals (aluminum, gold, silver, nickel, palladium, chromium, etc.), metal oxides (indium oxide, tin oxide, indium-tin oxide (ITO), indium-zinc oxide (IZO)) etc.), metal halides (such as copper iodide), copper sulfide, carbon black, ITO glass and Nessa glass. As an organic compound, conductive polymers, such as polythiophene, such as poly(3-methylthiophene), polypyrrole, and polyaniline, etc. are mentioned, for example. In addition, it can be used suitably selected from materials used as anodes of organic EL elements.

2-4. abandonment electric field radiation in small hole injection layer , hole transport layer

The hole injection layer 103 serves to efficiently inject holes moving from the anode 102 into the light emitting layer 105 or into the hole transport layer 104 . The hole transport layer 104 serves to efficiently transport holes injected from the anode 102 or holes injected from the anode 102 through 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 laminating or mixing one type or two or more types of hole injection/transport materials, respectively. Alternatively, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injection/transport material.

As the hole injection/transport material, it is necessary to efficiently inject/transport holes from the positive electrode between electrodes to which an electric field is applied, and it is preferable to have high hole injection efficiency and efficiently transport the injected holes. For this purpose, it is preferable to use a material that has a small ionization potential, a high hole mobility, excellent stability, and is difficult to generate trap impurities during production and use.

As the material forming the hole injection layer 103 and the hole transport layer 104, in the photoconductive material, a compound conventionally used as a hole charge transport material, a p-type semiconductor, a hole injection layer of an organic EL device, and a hole Any compound may be selected and used from known compounds used in the transport layer. 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 aromatic tertiary aminos in the main or side chains, 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane, N,N'-diphenyl-N,N'-di (3-methylphenyl)-4,4'-diaminobiphenyl, N,N'-diphenyl-N,N'-dinaphthyl-4,4'-diaminobiphenyl, N,N'-diphenyl -N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine, N,N'-dinaphthyl-N,N'-diphenyl-4,4'- Diphenyl-1,1'-diamine, N ⁴ ,N ^{4 '} -diphenyl-N ⁴ ,N ^{4 '} -bis(9-phenyl-9H-carbazol-3-yl)-[1,1'-bi phenyl] -4,4'-diamine, N ⁴ ,N ⁴ ,N ^{4 '} ,N ^4' -tetra[1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]- Triphenylamine derivatives such as 4,4'-diamine, 4,4',4"-tris(3-methylphenyl(phenyl)amino)triphenylamine, starburstamine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (no metals, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone-based compounds, benzofuran derivatives or thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (e.g., 1,4,5,8,9,12-hexaaza triphenylene-2,3,6,7,10,11-hexacarbonitrile, etc.), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. In the polymer system, polycarbonates or styrene derivatives having the above monomers in their side chains , polyvinylcarbazole, polysilane, etc. are preferable, but it is not particularly limited as long as it is a compound capable of forming a thin film necessary for manufacturing a light emitting device, injecting holes from an anode, and transporting holes.

It is also known that the conductivity of an organic semiconductor is strongly influenced by its doping. Such an organic semiconductor matrix material is composed of a compound having good electron donating property or a compound having good electron accepting property. For doping of electron-donating materials, strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are used. known (see, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(22), 3202-3204 (1998) and J. Blochwitz , M. Pfeiffer, T. Fritz, K. Leo, Appl. Phys. Lett., 73(6), 729-731 (1998)). These generate so-called holes by an electron transfer process in an electron donating base material (hole transport material). Depending on the number and mobility of holes, the conductivity of the base material varies considerably. As matrix materials having hole transport properties, for example, benzidine derivatives (TPD, etc.) or starburstamine derivatives (TDATA, etc.), or specific metal phthalocyanines (particularly, zinc phthalocyanine (ZnPc), etc.) are known (Japanese Patent Publication) Publication No. 2005-167175).

The material for the hole injection layer and the material for the hole transport layer described above are a polymer compound obtained by polymerizing a reactive compound substituted with a reactive substituent as a monomer, or a crosslinked polymer thereof, or a main chain polymer and the reactive compound reacted A pendant-type polymer compound or a pendant-type polymer crosslinked product thereof can also be used for the hole layer material.

2-5. Light emitting layer in an organic electroluminescent device

The light-emitting layer 105 is a layer that emits light by recombination of holes injected from the anode 102 and electrons injected from the cathode 108 between electrodes to which an electric field is applied. The material for forming the light-emitting layer 105 may be a compound that is excited by recombination of holes and electrons and emits light (luminescent compound), which can form a stable thin film and has strong light emission (fluorescence) efficiency in a solid state. A compound showing is preferred and used.

The light emitting layer included in the organic electroluminescent device of the present invention includes at least two materials selected from the group consisting of an emitting dopant, a hole transporting host material, an electron transporting host material, and an assisting dopant material. The light emitting layer may be a single layer or a plurality of layers, and each is formed of a material for the light emitting layer. When the light emitting layer is composed of a plurality of layers, any one layer in the organic electroluminescent device of the present invention may contain the above constituent material. The light emitting layer is preferably a single layer. The emitting dopant may be entirely or partially contained in the host material, or may be either. As a doping method, although it can form by the vapor-codepositing method with a host material, you may vapor-deposit simultaneously after mixing with a host material beforehand.

The amount of host material used varies depending on the type of host material, and may be determined according to the characteristics of the host material. The reference amount of the host material used is preferably 50 to 99.999% by mass, more preferably 80 to 99.95% by mass, still more preferably 90 to 99.9% by mass of the total mass of the material for the light emitting layer. When the host material is a combination of a hole-transporting host material and an electron-transporting host material, the amount of the host material used is the sum of the amount of the hole-transporting host material and the electron-transporting host material. The ratio of the amount of the hole-transporting host material and the electron-transporting host material used may be 1:9 to 9:1 in terms of mass ratio, preferably 4:6 to 6:4, and more preferably approximately 1:1.

The amount of the emitting dopant used varies depending on the type of the emitting dopant, and may be determined according to its characteristics. The amount of the emitting dopant used is preferably 0.001 to 50% by mass, more preferably 0.05 to 20% by mass, still more preferably 0.1 to 10% by mass of the total mass of the material for the light emitting layer. The above range is preferable from the viewpoint that, for example, the concentration quenching phenomenon can be prevented.

In an organic electroluminescent device using an assisting dopant (heat-activated delayed phosphor or phosphorescent material) in addition to an emitting dopant, the use of the emitting dopant material is low in concentration to prevent concentration quenching. desirable. A higher concentration of the assisting dopant is preferable from the viewpoint of energy transfer efficiency. A higher concentration of the assisting dopant is preferable from the viewpoint of the efficiency of the thermally activated delayed fluorescence device. In an organic electroluminescent device using a thermally activated delayed phosphor as an assisting dopant, in terms of the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant, the amount of the emission dopant is lower than the amount of the assisting dopant. desirable.

In the case where an assisting dopant material is used, the amount of host material, assisting dopant material, and emitting dopant material used is 40 to 99% by mass and 59 to 1% by mass, respectively, based on the total mass of the material for the light emitting layer. and 20 to 0.001% by mass, preferably 60 to 95% by mass, 39 to 5% by mass, and 10 to 0.01% by mass, more preferably 70 to 90% by mass, 29 to 10% by mass, and It is 5-0.05 mass %.

2-6. abandonment electric field radiation in small electron injection layer , electron transport layer

The electron injection layer 107 serves to efficiently inject electrons moving from the cathode 108 into the light emitting layer 105 or into the electron transport layer 106 . The electron transport layer 106 serves to efficiently transport electrons injected from the cathode 108 or electrons injected from the cathode 108 through the electron injection layer 107 to the light emitting layer 105 . The electron transport layer 106 and the electron injection layer 107 are formed by laminating or mixing one or more electron transport/injection materials, or a mixture of an electron transport/injection material and a polymeric binder.

The electron injection/transport layer is a layer responsible for injecting electrons from the cathode and transporting the electrons, and preferably has high electron injection efficiency and efficiently transports the injected electrons. For this purpose, it is preferable to use a material that has high electron affinity, high electron mobility, and excellent stability, and is unlikely to generate trap impurities during production and use. However, in the case of considering the transport balance of holes and electrons, in the case where the role of efficiently preventing the flow of holes to the anode without recombination to the cathode side is mainly performed, even if the electron transport capacity is not so high, the luminous efficiency is improved. The effect is equivalent to that of a material having a high electron transport ability. Therefore, the electron injection/transport layer in the present embodiment may also include a function of a layer capable of effectively blocking the movement of holes.

As the material (electron transport material) forming the electron transport layer 106 or the electron injection layer 107, a compound conventionally used as an electron transport compound in photoconductive materials, an electron injection layer and an electron transport layer of an organic EL device. It can be used by selecting it arbitrarily from known compounds in use.

As the material used for the electron transport layer or the electron injection layer, compounds comprising an aromatic ring or heteroaromatic ring composed of at least one atom selected from carbon, hydrogen, oxygen, sulfur, silicon and phosphorus, pyrrole derivatives and condensed ring derivatives thereof; It is preferable to contain at least 1 sort(s) selected from metal complexes which have electron-accepting nitrogen. Specifically, condensed ring aromatic ring derivatives such as naphthalene and anthracene, styryl aromatic ring derivatives represented by 4,4'-bis(diphenylethenyl)biphenyl, perinone derivatives, coumarin derivatives, and naphthalimide derivatives , quinone derivatives such as anthraquinone and diphenoquinone, phosphine oxide derivatives, arylnitrile derivatives, and indole derivatives. Examples of the metal complex having electron-accepting nitrogen include hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and benzoquinoline metal complexes. Although these materials are used alone, you may mix and use them with other materials.

In addition, as specific examples of other electron transfer compounds, pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone Derivatives, perylene derivatives, oxadiazole derivatives (1,3-bis[(4-t-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 auxin derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazoles compounds, gallium complexes, pyrazole derivatives, perfluorinated phenylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (2,2'-bis(benzo[h]quinolin-2-yl)-9,9' -spirofluorene, etc.), imidazopyridine derivatives, borane derivatives, benzoimidazole derivatives (tris(N-phenylbenzoimidazol-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"-terpyridin-4'-yl) benzene, etc.), naphthyridine derivatives (bis (1-naphthyl)-4-(1,8-naphthyridin-2-yl)phenyl phosphine oxide, etc.), aldazine derivatives, carbazole derivatives, indole derivatives, phosphine oxide derivatives, bisstyryl derivatives, etc. can be heard

In addition, metal complexes having electron-accepting nitrogen can also be used, for example, quinolinol-based metal complexes, hydroxyazole complexes such as hydroxyphenyloxazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes. and benzoquinoline metal complexes.

The above materials are used alone, but may be used in combination with other materials.

Among the above materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, arylnitrile derivatives, triazine derivatives, benzoimidazole derivatives, Phenanthroline derivatives, and quinolinol-based metal complexes are preferred.

<Reducible substance>

The electron transport layer or electron injection layer may further contain a substance capable of reducing a material forming the electron transport layer or electron injection layer. As long as this reducing substance has a certain reducing property, various substances are used, for example, alkali metals, alkaline earth metals, rare earth metals, oxides of alkali metals, halides of alkali metals, oxides of alkaline earth metals, and alkaline earths. At least one selected from the group consisting of 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.

Preferred reducing substances include alkali metals such as Na (work function: 2.36 eV), K (work function: 2.28 eV), Rb (work function: 2.16 eV), or Cs (work function: 1.95 eV); Ca (work function: 2.9 eV); Alkaline-earth metals, such as Sr (work function: 2.0-2.5 eV) or Ba (work function: 2.52 eV), are particularly preferred. Among these, a more preferable reducing substance is an alkali metal of K, Rb or Cs, even more preferably Rb or Cs, and most preferably Cs. These alkali metals have particularly high reducing ability, and the addition of a relatively small amount to the material forming the electron transport layer or the electron injection layer can improve the light emission luminance and lengthen the lifetime of the organic EL device. In addition, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more alkali metals is also preferable, and in particular, a combination containing Cs, for example, Cs and Na, Cs and K, Cs and Rb, or Cs and a combination of Na and K is preferred. By including Cs, reducing ability can be exhibited efficiently, and addition to the material forming the electron transport layer or electron injection layer can improve the luminescence brightness and lengthen the lifetime of the organic EL device.

2-7. abandonment electric field radiation in small cathode

The cathode 108 serves to inject electrons into the light emitting layer 105 through the electron injection layer 107 and the electron transport layer 106 .

The material forming the cathode 108 is not particularly limited as long as it is a material capable of efficiently injecting electrons into the organic layer, but the same material as the material forming the anode 102 can be used. Among them, metals or alloys thereof (magnesium-silver alloy, magnesium- aluminum-lithium alloys such as indium alloys and lithium fluoride/aluminum), etc. are preferable. In order to improve device characteristics by increasing electron injection efficiency, lithium, sodium, potassium, cesium, calcium, magnesium, or alloys containing these low work function metals are effective. However, these low work function metals are generally unstable in air in many cases. In order to improve this point, a method is known in which, for example, an organic layer is doped with a small amount of lithium, cesium or magnesium to use an electrode having high stability. As other dopants, inorganic salts such as lithium fluoride, cesium fluoride, lithium oxide and cesium oxide can also be used. However, it is not limited to these.

Furthermore, metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys using these metals, and inorganic substances such as silica, titania, and silicon nitride, polyvinyl alcohol, vinyl chloride, and hydrocarbons for electrode protection Preferred examples include laminating a polymeric compound or the like. Methods for producing these electrodes are not particularly limited as long as conduction can be achieved, such as resistance heating, electron beam evaporation, sputtering, ion plating and coating.

3. organic electric field Manufacturing method of light emitting element

For each layer constituting the organic EL device, the material constituting each layer is formed into a thin film by a method such as evaporation, resistance heating evaporation, electron beam evaporation, sputtering, molecular lamination method, printing method, spin coating method, casting method, or coating method. By doing so, it can be formed. The film thickness of each layer formed in this way is not particularly limited and can be appropriately set depending on the nature of the material, but is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a crystal oscillation type film thickness measuring device or the like. In the case of thinning using a vapor deposition method, the deposition conditions differ depending on the type of material, the target crystal structure and association structure of the film, and the like. Deposition conditions are generally: boat heating temperature +50 to +400 ° C, vacuum degree 10 ^-6 to 10 ^-3 Pa, deposition rate 0.01 to 50 nm / sec, substrate temperature -150 to +300 ° C film thickness in the range of 2 nm to 5 μm It is desirable to set appropriately in .

In the case of applying a direct current voltage to the organic EL element obtained in this way, the anode may be applied with + and the cathode as the polarity, and when a voltage of about 2 to 40 V is applied, the transparent or translucent electrode side (anode or cathode) , and both) can observe luminescence. In addition, this organic EL element emits light even when a pulse current or an alternating current is applied. In addition, the waveform of the alternating current to apply may be arbitrary.

Next, as an example of a method for manufacturing an organic EL device, a method for manufacturing an organic EL device composed of an anode/a hole injection layer/a hole transport layer/a light emitting layer composed of a host material and a dopant material/an electron transport layer/an electron injection layer/cathode Explain.

<Deposition method>

After fabricating an anode by forming a thin film of anode material on a suitable substrate by vapor deposition or the like, thin films of a hole injection layer and a hole transport layer are formed on the anode. A host material and a dopant material are co-evaporated on this to form a thin film to form a light emitting layer, an electron transport layer and an electron injection layer are formed on the light emitting layer, and a thin film made of a material for the cathode is formed by a vapor deposition method or the like to form a cathode, thereby forming a desired organic material. An EL element is obtained. In addition, in fabricating the organic EL device described above, it is also possible to reverse the fabrication order and fabricate the cathode, electron injection layer, electron transport layer, light emitting layer, hole transport layer, hole injection layer and anode in this order.

<Wet film forming method>

The wet film forming method is performed by preparing a low-molecular compound capable of forming each organic layer of an organic EL element as a liquid composition for forming an organic layer, and using the same. When there is no suitable organic solvent for dissolving the low molecular weight compound, a reactive compound obtained by substituting a reactive substituent in the low molecular weight compound and a composition for forming an organic layer from a high molecular compound polymerized together with other monomers having a soluble function or a main chain polymer, etc. you can prepare

In the wet film forming method, generally, a coating film is formed by passing through an application step of applying a composition for forming an organic layer to a substrate and a drying step of removing a solvent from the applied composition for forming an organic layer. When the polymer compound has a cross-linkable substituent (also referred to as a cross-linkable polymer compound), it is further cross-linked in this drying step to form a polymer cross-linked body. Depending on the difference in the coating process, the spin coat method uses a spin coater, the slit coat method uses a slit coater, and the gravure offset, reverse offset, flexographic printing, and inkjet printers are used for the plate method. The method of doing this is called the inkjet method, and the method of spraying in the form of mist is called the spray method. The drying process includes methods such as air drying, heating, and drying under reduced pressure. The drying step may be performed only once, or may be performed a plurality of times using different methods and conditions. In addition, you may use other methods together, such as baking under reduced pressure, for example.

The wet film forming method is a film forming method using a solution, and includes, for example, some printing methods (inkjet method), a spin coat method, a cast method, a coating method, and the like. Unlike the vacuum deposition method, the wet film formation method does not require the use of an expensive vacuum deposition apparatus and can form a film under atmospheric pressure. In addition, the wet film forming method enables large-area and continuous production, leading to reduction in manufacturing cost.

On the other hand, when compared with the vacuum evaporation method, the wet film formation method may be difficult to laminate. When a multilayer film is produced using a wet film forming method, it is necessary to prevent dissolution of the lower layer by the composition of the upper layer, so a composition with controlled solubility, cross-linking of the lower layer and orthogonal solvent (solvent that does not dissolve in each other), etc. this is spoken However, even if these techniques are used, there are cases where it is difficult to use the wet film formation method for coating all films.

Therefore, generally, a method of fabricating an organic EL device by using a wet film forming method for only a few layers and vacuum evaporation is employed for the rest.

For example, a procedure for fabricating an organic EL device by partially applying a wet film forming method is shown below.

(Procedure 1) Film formation by vacuum evaporation of the anode

(Procedure 2) Formation of a composition for forming a hole injection layer containing a material for a hole injection layer by a wet film forming method

(Procedure 3) Formation of a composition for forming a hole transport layer containing a material for a hole transport layer by a wet film forming method

(Procedure 4) Formation of a composition for forming a light emitting layer containing a host material and a dopant material by a wet film forming method

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

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

(Procedure 7) Film formation by vacuum evaporation of cathode

By passing through this sequence, an organic EL device composed of anode/hole injection layer/hole transport layer/light emitting layer composed of host material and dopant material/electron transport layer/electron injection layer/cathode is obtained.

Of course, the electron transport layer and the electron injection layer may also be formed by a wet film forming method using a composition for layer formation containing a material for an electron transport layer and a material for an electron injection layer, respectively. At this time, it is preferable to use a means for preventing dissolution of the lower light emitting layer or a means for forming a film from the cathode side in the opposite order to the above procedure.

<Other Tabernacling Methods>

A laser heating drawing method (LITI) can be used for film formation of the composition for forming an organic layer. LITI is a method of heating and depositing a compound attached to a substrate with a laser, and a composition for forming an organic layer can be used for a material applied to the substrate.

<Random process>

Appropriate treatment steps, washing steps, and drying steps may be suitably incorporated before and after each step of film formation. Examples of the treatment step include exposure treatment, plasma surface treatment, ultrasonic treatment, ozone treatment, washing treatment using an appropriate solvent, heat treatment, and the like. In addition, a series of steps for producing a bank are also mentioned.

A photolithography technique can be used for fabrication of the bank. As a bank material for which photolithography can be used, a positive type resist material and a negative type resist material can be used. In addition, patternable printing methods such as inkjet printing, gravure offset printing, reverse offset printing, and screen printing can also be used. In this case, a permanent resist material may be used.

Materials used for the bank include polysaccharides and their derivatives, homopolymers and copolymers of hydroxyl-containing ethylenic monomers, biomolecular compounds, polyacryloyl compounds, polyesters, polystyrenes, polyimides, polyamideimides, and polyethers. Mead, polysulfide, polysulfone, polyphenylene, polyphenylether, polyurethane, epoxy (meth)acrylate, melamine (meth)acrylate, polyolefin, cyclic polyolefin, acrylonitrile-butadiene-styrene copolymer (ABS ), silicone resin, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, polyacetate, polynorbornene, synthetic rubber, polyfluorovinylidene, polytetrafluoroethylene, fluorinated polymers such as polyhexafluoropropylene, fluoropolymers Although a copolymer polymer of olefin-hydrocarbon olefin and a fluorocarbon polymer are mentioned, it is not limited only to them.

<Composition for Forming Organic Layer Used in Wet Film Formation>

A composition for forming an organic layer is obtained by dissolving a low-molecular compound capable of forming each organic layer of an organic EL device or a high-molecular compound obtained by polymerizing the low-molecular compound in an organic solvent. For example, a composition for forming a light emitting layer includes at least one polycyclic aromatic compound (or a polymer compound thereof) as a dopant material as a first component, at least one host material as a second component, and at least one as a third component. Contains a species of organic solvent. The first component functions as a dopant component of the light emitting layer obtained from the composition, and the second component functions as a host component of the light emitting layer. The third component functions as a solvent that dissolves the first and second components in the composition, and upon application, imparts a smooth and uniform surface shape by the controlled evaporation rate of the third component itself.

<Organic Solvent>

The composition for forming an organic layer contains at least one organic solvent. By controlling the evaporation rate of the organic solvent at the time of film formation, film formability, the presence or absence of defects in the coating film, surface roughness, and smoothness can be controlled and improved. Further, in the case of film formation using the inkjet method, the meniscus stability in the pinhole of the inkjet head can be controlled to control and improve ejection properties. In addition, by controlling the drying speed of the film and the orientation of the derivative molecules, it is possible to improve the electrical characteristics, light-emitting characteristics, efficiency, and lifetime of an organic EL device having an organic layer obtained from the composition for forming an organic layer.

(1) physical properties of organic solvents

The boiling point of the at least one organic solvent is 130°C to 300°C, more preferably 140°C to 270°C, still more preferably 150°C to 250°C. When the boiling point is higher than 130°C, it is preferable from the viewpoint of inkjet ejection properties. In addition, when the boiling point is lower than 300 ° C., it is preferable from the viewpoint of defects, surface roughness, residual solvent and smoothness of the coating film. The organic solvent is more preferably composed of two or more organic solvents from the viewpoints of good inkjet ejection properties, film formability, smoothness, and low residual solvent. On the other hand, in some cases, a composition made into a solid state by removing the solvent from the composition for forming an organic layer may be used in consideration of transportability and the like.

Furthermore, the organic solvent contains a good solvent (GS) and a poor solvent (PS) for at least one solute, and the boiling point of the good solvent (GS) (BP _GS ) is the boiling point of the poor solvent (PS) (BP _PS ) A lower, configuration is particularly preferred.

By adding a poor solvent with a high boiling point, the good solvent with a low boiling point first volatilizes during film formation, and the concentrations of the content and the poor solvent in the composition increase, thereby promoting rapid film formation. Thereby, a coating film with few defects, small surface roughness, and high smoothness is obtained.

The difference in solubility (S _GS -S _PS ) is preferably 1% or more, more preferably 3% or more, and still more preferably 5% or more. The difference in boiling point (BP _PS -BP _GS ) is preferably 10°C or higher, more preferably 30°C or higher, and still more preferably 50°C or higher.

After film formation, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, or heating. In the case of heating, from the viewpoint of improving coating film formability, it is preferable to perform heating at a glass transition temperature (Tg) of at least one of the solutes +30°C or lower. Further, from the viewpoint of reducing the residual solvent, it is preferable to heat the glass transition point (Tg) of at least one of the solutes to -30°C or higher. Since the film is thin even when the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is sufficiently removed. Moreover, drying may be performed multiple times at different temperatures, or a plurality of drying methods may be used in combination.

(2) Specific examples of organic solvents

Examples of organic solvents used in the composition for forming an organic layer include alkylbenzene solvents, phenyl ether solvents, alkyl ether solvents, cyclic ketone solvents, aliphatic ketone solvents, monocyclic ketone solvents, solvents having a diester skeleton, and fluorine-based solvents and the like, and specific examples include pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, hexan-2-ol, heptan-2- Ol, octan-2-ol, decan-2-ol, dodecan-2-ol, cyclohexanol, α-terpineol, β-terpineol, γ-terpineol, δ-terpineol, ter Pineol (mixture), ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, dipropylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol monobutyl ether, ethylene glycol monophenyl ether, Triethylene glycol monomethyl ether, diethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, polyethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, p-xylene, m-xylene, o-xylene, 2,6-lutidine , 2-fluoro-m-xylene, 3-fluoro-o-xylene, 2-chlorobenzotrifluoride, cumene, toluene, 2-chloro-6-fluorotoluene, 2-fluoroanisole, anisole, 2,3-dimethylpyrazine, bromobenzene, 4-fluoroanisole, 3-fluoroanisole, 3-trifluoromethylanisole, mesitylene, 1,2,4-trimethylbenzene, t-butylbenzene , 2-methylanisole, phenetole, benzodioxole, 4-methylanisole, s-butylbenzene, 3-methylanisole, 4-fluoro-3-methylanisole, cymene, 1,2,3- Trimethylbenzene, 1,2-dichlorobenzene, 2-fluorobenzonitrile, 4-fluoroveratrol, 2,6-dimethylanisole, n-butylbenzene, 3-fluorobenzonitrile, decalin (decahydronaphthalene) , neopentylbenzene, 2,5-dimethylanisole, 2,4-dimethylanisole, benzonitrile, 3,5-dimethylanisole, diphenyl ether, 1-fluoro-3,5-dimethoxybenzene, benzoic acid Methyl, isopentylbenzene, 3,4-dimethylanisole, o-tolnitrile, n-amylbenzene, veratrol, 1,2,3,4-tetrahydronaphthalene, ethyl benzoate, n-hexylbenzene, propyl benzoate, Cyclohexylbenzene, 1-methylnaphthalene, butyl benzoate, 2-methylbiphenyl, 3-phenoxytoluene, 2,2'-bitolyl, dodecylbenzene, dipentylbenzene, tetramethylbenzene, trimethoxybenzene, tri Methoxytoluene, 2,3-dihydrobenzofuran, 1-methyl-4-(propoxymethyl)benzene, 1-methyl-4-(butyloxymethyl)benzene, 1-methyl-4-(pentyloxymethyl) benzene, 1-methyl-4-(hexyloxymethyl)benzene, 1-methyl-4-(heptyloxymethyl)benzene, benzylbutyl ether, benzylpentyl ether, benzylhexyl ether, benzylheptyl ether, benzyloctyl ether, etc. can, but is not limited to that. In addition, a solvent may be used singly or may be mixed.

<Optional ingredients>

The composition for forming an organic layer may contain arbitrary components within a range that does not impair its properties. As an arbitrary component, a binder, surfactant, etc. are mentioned.

(1) Binder

The composition for forming an organic layer may contain a binder. The binder forms a film at the time of film formation and bonds the obtained film to the substrate. In addition, it serves to dissolve, disperse, and bind other components in the composition for forming the organic layer.

Examples of the binder used in the organic layer-forming composition include acrylic resin, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylonitrile-ethylene-styrene copolymer (AES) resin, and Ionomer, chlorinated polyether, diallylphthalate resin, unsaturated polyester resin, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, Teflon, acrylonitrile-butadiene-styrene copolymer (ABS) resins, acrylonitrile-styrene copolymer (AS) resins, phenolic resins, epoxy resins, melamine resins, urea resins, alkyd resins, polyurethanes, and copolymers of the above resins and polymers, but are not limited thereto. don't

The binder used in the composition for forming an organic layer may be used alone or in combination of multiple types.

(2) Surfactant

The composition for forming an organic layer may contain, for example, a surfactant for controlling the uniformity of the film surface and the solvent affinity and liquid repellency of the film surface of the composition for forming an organic layer. Surfactants are classified into ionic and nonionic based on the structure of the hydrophilic group, and further classified into alkyl, silicon and fluorine based based on the structure of the hydrophobic group. In addition, from the structure of the molecule, it is classified into a monomolecular system having a relatively small molecular weight and a simple structure, and a macromolecular system having a large molecular weight and having side chains or branches. Also, from the composition, it is classified into a single system and a mixed system in which two or more types of surfactants and a substrate are mixed. As the surfactant that can be used in the composition for forming the organic layer, all kinds of surfactants can be used.

As surfactant, for example, Polyflow No.45, Polyflow KL-245, Polyflow No.75, Polyflow No.90, Polyflow No.95 (trade name, manufactured by Kyoeisha Chemical Industry Co., Ltd.) , Disperbyk 161, Disperbake 162, Disperbake 163, Disperbake 164, Disperbake 166, Disperbake 170, Disperbake 180, Disperbake 181, Disperbake 182, BYK300 , BYK306, BYK310, BYK320, BYK330, BYK342, BYK344, BYK346 (trade name, manufactured by Big Chemie Japan Co., Ltd.), KP-341, KP-358, KP-368, KF-96-50CS, KF-50-100CS (brand name, manufactured by Shin-Etsu Chemical Co., Ltd.), Suplon SC-101, Suplon KH-40 (brand name, manufactured by Seimi Chemical Co., Ltd.), Phtagent 222F, Phtagent 251, FTX-218 (brand name, ( Neos Co., Ltd.), EFTOP EF-351, EFTOP EF-352, EFTOP EF-601, EFTOP EF-801, EFTOP EF-802 (trade name, manufactured by Mitsubishi Materials Co., Ltd.), Megafac F-470, Megafac F-471, Megafac F-475, Megafac R-08, Megafac F-477, Megafac F-479, Megafac F-553, Megafac F-554 (trade name, manufactured by DIC Co., Ltd.), Fluo Alkylbenzene sulfonate, fluoroalkyl carboxylate, fluoroalkyl polyoxyethylene ether, fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl sulfonate, diglycerin tetrakis (fluoroalkyl poly oxyethylene ether), fluoroalkyltrimethylammonium salt, fluoroalkylaminosulfonic acid salt, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene laurate, polyoxyethylene oleate, Polyoxyethylene stearate, polyoxyethylene laurylamine, sorbitan laurate, sorbitan palmitate, sorbitan stearate, sorbitan oleate, sorbitan fatty acid ester, polyoxyethylene sorbitan laurate, polyoxyethylene sorbate bitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitanolate, polyoxyethylene naphthyl ether, alkylbenzene sulfonate and alkyl diphenyl ether disulfonate.

In addition, surfactant may be used by 1 type, and may use 2 or more types together.

<Composition and physical properties of composition for forming organic layer>

The content of each component in the composition for forming an organic layer depends on the good solubility, storage stability and film formability of each component in the composition for forming an organic layer, the quality of a coating film obtained from the composition for forming an organic layer, and the inkjet method. It is determined in consideration of the good ejection properties in the case of use, and the good electrical characteristics, light emitting characteristics, efficiency, and lifetime of an organic EL device having an organic layer produced using the composition. For example, in the case of the composition for forming a light emitting layer, the first component is 0.0001% by mass to 2.0% by mass with respect to the total mass of the composition for forming a light emitting layer, and the second component is 0.0999 mass% with respect to the total mass of the composition for forming a light emitting layer. % to 8.0% by mass, and the third component is preferably 90.0% to 99.9% by mass with respect to the total mass of the composition for forming a light emitting layer.

More preferably, the first component is 0.005% by mass to 1.0% by mass, the second component is 0.095% to 4.0% by mass, based on the total mass of the composition for forming a light emitting layer, based on the total mass of the composition for forming a light emitting layer. The three components are 95.0% by mass to 99.9% by mass with respect to the total mass of the composition for forming a light emitting layer. More preferably, the first component is 0.05% by mass to 0.5% by mass, the second component is 0.25% to 2.5% by mass, based on the total mass of the composition for forming a light emitting layer, based on the total mass of the composition for forming a light emitting layer, The 3rd component is 97.0 mass % - 99.7 mass % with respect to the total mass of the composition for light emitting layer formation.

The composition for forming an organic layer can be prepared by appropriately selecting and performing stirring, mixing, heating, cooling, dissolution, dispersion, etc. of the above-mentioned components by a known method. After preparation, filtration, degassing (also referred to as degassing), ion exchange treatment, and inert gas substitution/encapsulation treatment may be appropriately selected and performed.

As for the viscosity of the composition for forming an organic layer, those with high viscosity give good film formability and good ejection properties in the case of using the inkjet method. On the other hand, it is easy to make a thin film of low viscosity. From this, it is preferable that the viscosity in 25 degreeC of the viscosity of this composition for organic layer formation is 0.3-3 mPa*s, and it is more preferable that it is 1-3 mPa*s. In the present invention, the viscosity is a value measured using a conical plate type rotational viscometer (conical plate type).

As for the surface tension of the composition for forming an organic layer, the lower the surface tension, the better film formability and defect-free coating can be obtained. On the other hand, a higher one obtains good inkjet ejection properties. From this, it is preferable that the surface tension in 25 degreeC of this composition for organic layer formation is 20-40 mN/m, and it is more preferable that it is 20-30 mN/m. In the present invention, the surface tension is a value measured using the hanging drop method.

<Crosslinkable High Polymer Compound: Compound Represented by Formula (XLP-1)>

Next, the case where the above-mentioned high molecular compound has a crosslinkable substituent is demonstrated. Such a crosslinkable high molecular compound is, for example, a compound represented by the following formula (XLP-1).

In formula (XLP-1),

MUx is a divalent group each independently represented by removing any two hydrogen atoms from an aromatic compound, ECx is a monovalent group each independently represented by removing any one hydrogen atom from an aromatic compound, and 2 in MUx Two hydrogens are substituted with ECx or MUx, and k is an integer from 2 to 50000. However, the compound represented by formula (XLP-1) has at least one crosslinkable substituent (XLS), and the content of the monovalent or divalent aromatic compound preferably having a crosslinkable substituent is 0.1 to 80 mass in the molecule. %am.

More specifically,

MUx is each independently arylene, heteroarylene, diarylene arylamino, diarylene arylboryl, oxaborine-diyl, azaborin-diyl,

ECx is, each independently, hydrogen, aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino or aryloxy;

At least one hydrogen in MUx and ECx may be further substituted with aryl, heteroaryl, diarylamino, alkyl and cycloalkyl;

k is an integer from 2 to 50000;

It is preferable that k is an integer of 20-50000, and it is more preferable that it is an integer of 100-50000.

At least one hydrogen in MUx and ECx in formula (XLP-1) may be substituted with C1-C24 alkyl, C3-C24 cycloalkyl, halogen or deuterium, and furthermore, in the alkyl Optional -CH ₂ - may be substituted with -O- or -Si(CH ₃ ) ₂ -, and in the above alkyl, any of -CH ₂ - except for -CH 2 - directly linked to ECx in formula (XLP-1) -CH ₂ - may be substituted with arylene having 6 to 24 carbon atoms, and any hydrogen in the alkyl may be substituted with fluorine.

Examples of MUx include divalent groups represented by removing two arbitrary hydrogen atoms from any one of the compounds below.

More specifically, a divalent group represented by any one of the following structures is exemplified. In these, MUx is combined with another MUx or ECx in *.

Moreover, as ECx, the monovalent group represented by any one of the following structures is mentioned, for example. In these, ECx binds MUx at *.

In the compound represented by formula (XLP-1), from the viewpoint of solubility and coating film forming property, 10 to 100% of the MU of the total number (k) of MU in the molecule preferably has an alkyl having 1 to 24 carbon atoms, and the MU in the molecule It is more preferable that 30 to 100% of the total number (k) of MU has an alkyl having 1 to 18 carbon atoms (branched chain alkyl having 3 to 18 carbon atoms), and 50 to 100% of the total number of MUs (k) in the molecule is It is more preferable to have an alkyl of 1 to 12 carbon atoms (branched chain alkyl of 3 to 12 carbon atoms). On the other hand, from the viewpoint of in-plane orientation and charge transport, it is preferable that 10 to 100% of the MUs of the total number of MUs (k) in the molecule have an alkyl having 7 to 24 carbon atoms, and 30 to 100% of the total number of MUs (k) in the molecule It is more preferable that MU of has C7-C24 alkyl (C7-C24 branched chain alkyl).

0.5-50 mass % is preferable, and, as for content of the monovalent or divalent aromatic compound which has a crosslinkable substituent, 1-20 mass % is more preferable.

The crosslinkable substituent (XLS) is not particularly limited as long as it is a group capable of further crosslinking the polymer compound described above, but a substituent having the following structure is preferable. * in each structural formula represents a bonding position.

L is, each independently, a single bond, -O-, -S-, >C=O, -O-C(=O)-, C1-C12 alkylene, C1-C12 oxyalkylene, and C1 It is a polyoxyalkylene of ~12. Among the above substituents, a group represented by formula (XLS-1), formula (XLS-2), formula (XLS-3), formula (XLS-9), formula (XLS-10) or formula (XLS-17) is preferable. and a group represented by formula (XLS-1), formula (XLS-3) or formula (XLS-17) is more preferred.

As a divalent aromatic compound which has a crosslinkable substituent, the compound which has the following partial structure is mentioned, for example. * in the following structural formula represents a bonding position.

<Method for producing high molecular compound and crosslinkable high molecular compound>

The method for producing the high molecular compound and the crosslinkable high molecular compound will be described by taking the compound represented by the above formula (XLP-1) as an example. These compounds can be synthesized by appropriately combining known production methods.

Examples of the solvent used in the reaction include aromatic solvents, saturated/unsaturated hydrocarbon solvents, alcohol solvents, and ether solvents, and examples thereof include dimethoxyethane, 2-(2-methoxyethoxy)ethane, 2- (2-ethoxyethoxy) ethane etc. are mentioned.

Also, the reaction may be performed in a two-phase system. In the case of reacting in a two-phase system, a phase transfer catalyst such as a quaternary ammonium salt may be added as needed.

When producing the compound of Formula (XLP-1), it may be produced in one step or may be produced through multiple steps. In addition, it may be carried out by a batch polymerization method in which the reaction is started after all the raw materials are put into the reaction vessel, or may be carried out by a drop polymerization method in which the raw materials are added dropwise to the reaction vessel, or the product precipitates as the reaction proceeds. You may carry out by polymerization method, and it is compoundable by combining these suitably. For example, when synthesizing the compound represented by formula (XLP-1) in one step, a monomer having a polymerizable group bonded to the monomer unit (MU) and a monomer having a polymerizable group bonded to the end cap unit (EC) are placed in a reaction vessel. A target object is obtained by reacting in the added state. In addition, when synthesizing the compound represented by Formula (XLP-1) in multiple steps, after polymerizing the monomer having a polymerizable group bonded to the monomer unit (MU) to a desired molecular weight, the monomer having a polymerizable group bonded to the end cap unit (EC) The target product is obtained by adding and reacting. When a monomer having a polymerizable group bonded to different types of monomer units (MU) is added and reacted in multiple stages, a polymer having a concentration gradient with respect to the structure of the monomer units can be produced. In addition, after preparing the precursor polymer, the target polymer can be obtained by post-reaction.

In addition, the primary structure of the polymer can be controlled by selecting the polymerizable group of the monomer unit (MU). For example, as shown in synthesis schemes 1 to 3, a polymer having a random primary structure (synthesis scheme 1), a polymer having a regular primary structure (synthesis scheme 2 and 3), etc. are synthesized. It is possible, and it can be used in appropriate combination according to the target object. Furthermore, if a monomer having three or more polymerizable groups is used, a hyperbranched polymer or a dendrimer can be synthesized.

Monomers that can be used in the present invention are Japanese Patent Application Publication No. 2010-189630, International Publication No. 2012/086671, International Publication No. 2013/191088, International Publication No. 2002/045184, International Publication No. 2011/049241, International Publication No. 2013/146806, International Publication No. 2005/049546, International Publication No. 2015/145871, Japanese Patent Application Publication No. 2010-215886, Japanese Patent Application Publication No. 2008-106241, International Publication No. 2016/031639, Japan It is compoundable according to the method described in Unexamined-Japanese-Patent No. 2011-174062.

In addition, regarding the specific polymer synthesis procedure, Japanese Patent Laid-Open No. 2012-036388, International Publication No. 2015/008851, Japanese Patent Laid-Open No. 2012-36381, Japanese Patent Laid-Open No. 2012-144722, International Publication No. 2015/194448 International Publication No. 2013/146806, International Publication No. 2015/145871, International Publication No. 2016/031639, International Publication No. 2016/125560, and International Publication No. 2011/049241 may be referred to.

4. Application Examples of Organic Electroluminescent Devices

INDUSTRIAL APPLICABILITY The present invention can also be applied to a display device including an organic EL element or a lighting device including an organic EL element.

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 according to the present embodiment to a known drive device, and known DC drive, pulse drive, AC drive, etc. It can be driven by appropriately using the driving method of .

Examples of the display device include a panel display such as a color flat panel display, a flexible display such as a flexible color organic electroluminescent (EL) display, and the like (eg, Japanese Patent Laid-Open No. 10-335066, Japanese Unexamined Patent Publication No. 2003-321546, Japanese Unexamined Patent Publication No. 2004-281086, etc.). In addition, as a display method of a display, a matrix method, a segment method, etc. are mentioned, for example. Also, the matrix display and the segment display may coexist in the same panel.

In the matrix, pixels for display are two-dimensionally arranged in a lattice or mosaic form, and characters or images are displayed by a set of pixels. The shape or size of the pixel is determined according to the purpose. For example, for displaying images and characters on computers, monitors, and televisions, square pixels with sides of 300 μm or less are usually used, and in the case of large displays such as display panels, pixels on the order of mm are used. will do In the case of monochrome display, pixels of the same color may be arranged, but in the case of color display, red, green, and blue pixels are arranged and displayed. In this case, there are typically a delta type and a stripe type. Incidentally, as a driving method for this matrix, either a line-sequential driving method or an active matrix may be used. Line-sequential driving has the advantage of having a simple structure, but when operating characteristics are taken into consideration, the active matrix method may be superior, so it is necessary to use this also according to the purpose.

In the segment method (type), a pattern is formed to display predetermined information, and a predetermined area is illuminated. For example, the time or temperature display in a digital watch or thermometer, the operation state display of an audio device or electric cooker, and the panel display of a car etc. are mentioned.

Examples of the lighting device include lighting devices such as indoor lighting, backlights of liquid crystal display devices, and the like (for example, Japanese Patent Laid-Open No. 2003-257621, Japanese Patent Laid-Open No. 2003-277741, Japanese Patent). Publication No. 2004-119211, etc.). Backlights are mainly used for the purpose of improving the visibility of display devices that do not emit self-luminescence, and are used for liquid crystal display devices, clocks, audio devices, automobile panels, display panels, and signs. In particular, considering that it is difficult to reduce the thickness of a liquid crystal display device, especially a backlight for a computer where thinning is a problem, because the conventional method consists of a fluorescent lamp or a light guide plate, the backlight using the light emitting element according to the present embodiment is thin. and is characterized by being lightweight.

[Example]

Hereinafter, the present invention will be described more specifically by means of examples, but the present invention is not limited thereto. On the other hand, in the examples, "NMR" means nuclear magnetic resonance, and "MALDI-TOF-MS" means "matrix-assisted laser-assisted ionization time-of-flight mass spectrometry."

<<synthesis example>>

Synthesis Example (1): Synthesis of Compound (1-1)

Under nitrogen atmosphere, compound (I-1) (0.120 g, 0.10 mmol), boron triiodide (0.315 g, 0.80 mmol), 2,6-di-tert-butyl pyridine (0.130 ml, 0.60 mmol) and 1,2 - Schlenk containing dichlorobenzene (1.0 ml) was stirred at room temperature for 4 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 10ml) was added to the reaction mixture at 0°C, the water layer was separated, and extracted with dichloromethane (20ml, 3 times). Thereafter, the obtained crude product was subjected to silica gel chromatography (eluent: hexane/ethyl acetate = 5/1), washed with hexane (20 ml) and acetonitrile (5.0 ml), and silica gel chromatography (eluent: hexane/toluene = 1/1), compound (1-1) (20.5 mg, yield 17%) could be obtained as a yellow solid.

The structure of compound (1-1) was confirmed by NMR and MALDI-TOF/MS measurements.

¹ H-NMR (500 MHz, CDCl ₃ ): δ=1.28 (s, 18H), 5.97 (s, 2H), 6.82 (d, J = 8.6 Hz, 2H), 6.95 (t, J = 7.4 Hz, 4H) , 6.99(d, J = 7.4 Hz, 8H), 7.14 (t, J = 7.2 Hz, 8H), 7.23 (t, J = 7.2 Hz, 2H), 7.26(s, 2H) 7.38-7.47 (m, 10H) ), 7.53 (t, J = 8.0 Hz, 4H), 8.35 (s, 2H), 8.51 (d, J = 8.0 Hz, 2H), 8.78 (d, J = 8.0 Hz, 2H), 10.17 (s, 1H) ).

HRMS (MALDI-TOF/MS): m/z [M]+ calcd for C86H67B3N61216.573, observed 1216.572.

Synthesis Example (2): Synthesis of Compound (1-2)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1240.57

Synthesis Example (3): Synthesis of Compound (1-3)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1294.65

Synthesis Example (4): Synthesis of Compound (1-4)

To a flask containing compound (I-4) (1.2 g) and tert-butyl benzene (7.0 ml), a 1.6 M tert-butyllithium pentane solution (3.2 ml) was added at -30°C under a nitrogen atmosphere. After completion of the dropwise addition, the temperature was raised to 60°C and stirred for 2 hours, and then components having a lower boiling point than tert-butylbenzene were distilled off under reduced pressure. It cooled to -30 degreeC, added boron tribromide (1.3g), heated up to room temperature, and stirred for 0.5 hour. After that, it was cooled to 0°C again, N,N-diisopropylethylamine (0.86 ml) was added, and the mixture was stirred at room temperature until the heat generation subsided, then the temperature was raised to 120°C and the mixture was heated and stirred for 3 hours. The reaction solution was cooled to room temperature, and an aqueous solution of sodium acetate cooled in an ice bath was added followed by heptane to separate the solutions. Then, after purification with a silica gel short pass column (eluent: toluene), the solvent was distilled off under reduced pressure, the obtained solid was dissolved in toluene, and heptane was added to precipitate again to obtain compound (1-4) (0.21 g). .

MALDI-TOF-MS(M+)=1078.64

Synthesis Example (5): Synthesis of Compound (1-5)

Under a nitrogen atmosphere, compound (I-5) (0.131 g, 0.10 mmol), boron triiodide (0.317 g, 0.81 mmol), 2,6-di-tert-butyl pyridine (0.130 ml, 0.60 mmol) and chlorobenzene ( 1.0 ml) was stirred at 50 ° C. for 24 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 10 ml) was added to the reaction mixture at 0°C, the water layer was separated, and extracted with dichloromethane (20 ml, 3 times). Thereafter, the obtained crude product was subjected to silica gel chromatography (eluent: hexane/toluene = 1/1, ethyl acetate), and washed with hexane (10 ml) to obtain compound (1-5) (27.1 mg, yield 20%). Obtained as a yellow solid.

The structure of compound (1-5) was confirmed by NMR and MALDI-TOF/MS measurements.

¹ H-NMR (400 MHz, CDCl ₃ ): δ = 1.28 (s, 18H), 2.26 (s, 12H), 2.41 (s, 6H), 2.43 (s, 6H), 5.85 (s, 2H), 6.77 ( d, J = 8.7 Hz, 2H), 6.87 (d, J = 8.7 Hz, 8H), 6.94 (d, J = 8.2 Hz, 8H), 7.26-7.30 (m, 12H), 7.37 (d, J = 7.8 Hz, 2H), 8.32(s, 2H), 8.49(d, J = 7.8 Hz, 2H), 8.68(s, 2H), 10.34(s, 1H).

HRMS (MALDI-TOF/MS): m/z [M]+ calcd for C94H83B3N61328.699, observed 1328.700.

Synthesis Example (6): Synthesis of Compound (1-6)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1368.63

Synthesis Example (7): Synthesis of Compound (1-7)

Under a nitrogen atmosphere, compound (I-7) (0.124 g, 0.10 mmol), boron triiodide (0.315 g, 0.80 mmol), 2,6-di-tert-butyl pyridine (0.130 ml, 0.60 mmol) and chlorobenzene ( 1.0 ml) was stirred at 0°C for 2 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 10ml) was added to the reaction mixture at 0°C, the water layer was separated, and extracted with dichloromethane (20ml, 3 times). Then, the obtained crude product was subjected to silica gel chromatography (eluent: hexane/toluene = 3/2, 1/1, 1/2, hexane/ethyl acetate = 2/1, 3/2, ethyl acetate, dichloromethane/methanol = 4/1) was performed to obtain 162 mg of low-polar component and 26 mg of high-polar component. Acetic acid (1.0 ml) and toluene (1.0 ml) were added to the highly polar component, and the mixture was stirred at 110°C for 24 hours. Thereafter, saturated aqueous sodium hydrogen chloride solution (15 ml) was added, the water layer was separated, and extracted with dichloromethane (5.0 ml, 3 times). Thereafter, the obtained reaction mixture and the low-polar component were washed with acetonitrile (100 ml), acetonitrile (80 ml), hexane (70 ml), hexane (250 ml), hexane (300 ml), and octane (300 ml), followed by silica gel chromatography. The compound (1-7) (17 mg, yield 13%) was obtained as a yellow solid by carrying out graphography (eluent: hexane/toluene = 1/1).

The structures of compounds (1-7) were confirmed by NMR and MALDI-TOF/MS measurements.

¹ H-NMR (500 MHz, C ₂ D ₂ Cl ₄ ): δ=5.78 (s, 2H), 6.75-6.87 (m, 22H), 7.26 (t, J = 7.8 Hz, 2H), 7.29 (s, 2H) ), 7.39-7.55 (m, 18H) 7.65 (d, J = 7.5 Hz, 2H), 7.70 (d, J = 7.5 Hz, 4H), 8.48 (s, 2H), 8.64 (d, J = 8.0 Hz, 2H), 8.77 (d, J = 8.0 Hz, 2H), 10.21 (s, 1H).

HRMS (MALDI-TOF/MS): m/z [M]+ calcd for C90H59B3N61256.511, observed 1256.510.

Synthesis Example (8): Synthesis of Compound (1-8)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1408.57

Synthesis Example (9): Synthesis of Compound (1-9)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1560.63

Synthesis Example (10): Synthesis of Compound (1-10)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1212.54

Synthesis Example (11): Synthesis of Compound (1-11)

It was synthesized by a method according to Synthesis Example (4).

MALDI-TOF-MS(M+)=1034.49

Synthesis Example (12): Synthesis of Compound (1-12)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1157.50

Synthesis Example (13): Synthesis of Compound (1-13)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1141.52

Synthesis Example (14): Synthesis of Compound (1-14)

It was synthesized by a method according to Synthesis Example (4).

MALDI-TOF-MS(M+)=1102.45

Synthesis Example (15): Synthesis of Compound (1-15)

It was synthesized by a method according to Synthesis Example (4).

MALDI-TOF-MS(M+)=956.44

Synthesis Example (16): Synthesis of Compound (1-16)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1216.39

Synthesis Example (17): Synthesis of Compound (1-17)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1216.39

Synthesis Example (18): Synthesis of Compound (1-18)

It was synthesized by a method according to Synthesis Example (1).

MALDI-TOF-MS(M+)=1408.57

Synthesis Example (19): Synthesis of Compound (1-19)

Under a nitrogen atmosphere, Schlenk containing compound (I-19) (99.1 mg), boron triiodide (0.157 g) and chlorobenzene (1.0 ml) was stirred at 90°C for 16 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 10ml) was added to the reaction mixture at 0°C, the water layer was separated, extracted with dichloromethane (20ml, 3 times), and the solvent was distilled off under reduced pressure. Thereafter, the obtained crude product was subjected to silica gel chromatography (eluent: hexane/toluene = 4/1, 3/1) and washed with acetonitrile (20 ml) to obtain compound (1-19) (21.2 mg) as a yellow solid. got as

The structure was confirmed by NMR measurement.

¹ H-NMR (500 MHz, CDCl ₃ ): δ = 1.39 (s, 18H), 2.44 (s, 6H), 2.58 (s, 6H), 6.42 (s, 2H), 6.80 (d, 2H), 7.25 ( d, 2H), 7.34(d, 2H), 7.43(d, 2H), 7.52(d, 2H), 7.56-7.57 (m, 4H), 7.70(s, 2H), 8.40(s, 2H), 8.65 (d, 2H), 8.72 (s, 2H), 10.45 (s, 1H).

Synthesis Example (20): Synthesis of Compound (1-20)

Under nitrogen atmosphere, compound (1-19) (50.4mg), potassium hexacyanoferrous (II) acid (36.8mg), dichlorobis[di-t-butyl(4-dimethylaminophenyl)phosphino]palladium (II )((amphos) ₂ PdCl ₂ ) (9.7 mg), sodium carbonate (8.5 mg), and N,N-dimethylacetamide (DMAc) (DMAc) (1.0 mL) was stirred at 160°C for 16 hours in a flask. After cooling the reaction solution to room temperature, it was poured into water, and the aqueous layer was extracted with toluene. The resulting organic layer was concentrated under reduced pressure, and the residue was subjected to silica gel chromatography (eluent: hexane/toluene = 1/1, 1/2, 1/3, toluene) to obtain compound (1-20) (7.40 mg). Obtained as an orange solid.

The structure was confirmed by NMR measurement.

¹ H-NMR (500 MHz, CDCl ₃ ): δ = 1.39 (s, 18H), 2.45 (s, 6H), 2.61 (s, 6H), 6.70 (s, 2H), 6.87 (d, 2H), 7.25 ( d, 2H), 7.40(d, 2H), 7.43(d, 2H), 7.55(d, 2H), 7.59-7.63 (m, 4H), 7.93(s, 2H), 8.30(s, 2H), 8.68 (d, 2H), 8.71 (s, 2H), 10.45 (s, 1H).

Synthesis Example (21): Synthesis of Compound (1-21)

Under nitrogen atmosphere, compound (1-19) (50.6mg), 4-tert-butylphenylboronic acid (53.4mg), dichlorobis[di-t-butyl(4-dimethylaminophenyl)phosphino]palladium(II) A flask containing ((amphos) ₂ PdCl ₂ ) (8.2 mg), tripotassium phosphate (65.1 mg), and N,N-dimethylacetamide (DMAc) (1.0 mL) was stirred at 100°C for 1 hour. . After cooling the reaction solution to room temperature, it was poured into water, and the aqueous layer was extracted with toluene. The resulting organic layer was concentrated under reduced pressure, and the residue was subjected to silica gel chromatography (eluent: hexane/toluene = 3/1, 5/2, toluene) to obtain compound (1-21) (16.3 mg) as an orange solid. .

The structure was confirmed by NMR measurement.

¹ H-NMR (500 MHz, CDCl ₃ ): δ = 1.31 (s, 18H), 1.38 (s, 18H), 2.46 (s, 6H), 2.57 (s, 6H), 6.69 (s, 2H), 6.82 ( d, 2H), 7.32-7.36 (m, 8H), 7.41(d, 4H), 7.48(d, 2H), 7.53(d, 4H), 7.56(d, 2H), 7.92(s, 2H), 8.52 (s, 2H), 8.66 (d, 2H), 8.75 (s, 2H), 10.45 (s, 1H).

Synthesis Example (22): Synthesis of Compound (1-22)

It was synthesized by a method according to Synthesis Example (21).

MALDI-TOF-MS(M+)=1394.67

Synthesis Example (23): Synthesis of Compound (1-23)

Under a nitrogen atmosphere, Schlenk containing compound (I-23) (0.131 g), boron tribromide (0.154 ml), 2,6-di-tert-butyl pyridine (0.130 ml) and chlorobenzene (1.0 ml) was added to 140 ml. It was stirred at °C for 14 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 20ml) was added to the reaction mixture at 0°C, the water layer was separated, and extracted with dichloromethane (20ml, 3 times). After distilling off the solvent under reduced pressure, acetic acid (2.0 ml) and a mixed solvent (2.0 ml) of toluene/ethyl acetate = 1/1 were added to the obtained crude product, and the mixture was stirred at 80°C for 16 hours. Thereafter, a saturated aqueous solution of sodium hydrogen chloride (30 ml) was added, the water layer was separated, and extracted with dichloromethane (20 ml, 3 times). After distilling off the solvent under reduced pressure, the resulting reaction mixture was subjected to silica gel chromatography (eluent: hexane/toluene = 2/1, 3/2), and washed with hexane (10 ml) to obtain compound (1-23) (12.1 mg). was obtained as a yellow solid.

The structure was confirmed by NMR measurement.

^1H -NMR (500MHz, CDCl ₃ ): δ=1.32(s, 18H), 2.35(s, 12H), 2.56(s, 6H), 2.78(s, 6H), 7.26-7.30 (m, 18H), 7.42(d, 2H), 7.52(s, 2H), 7.65(d, 2H), 7.84(s, 2H), 8.00(s, 2H), 8.19(s, 2H), 8.34(s, 2H), 8.53 (d, 2H), 8.78 (s, 2H), 10.51 (s, 1H).

Synthesis Example (24): Synthesis of Compound (1-24)

Under nitrogen atmosphere, compound (I-24) (0.132g), boron triiodide (0.312g), 2,6-di-tert-butyl pyridine (0.130ml) and 1,2-dichlorobenzene (1.0ml) were added. The Schlenk was stirred at 90°C for 14 hours. Thereafter, a phosphate buffer solution (pH = 6.8, 10ml) was added to the reaction mixture at 0°C, the water layer was separated, and extracted with dichloromethane (20ml, 3 times). After distilling off the solvent under reduced pressure, the obtained crude product was subjected to silica gel chromatography (eluent: hexane/toluene = 5/2, 2/1), washed with octane (10 ml), and the solvent was distilled off under reduced pressure to obtain compound (1) -24) (11.4 mg) was obtained as a yellow solid.

The structure was confirmed by NMR measurement.

¹ H-NMR (500 MHz, CDCl ₃ ): δ = 1.21 (s, 9H), 1.36 (s, 9H), 2.30 (s, 6H), 2.36 (s, 3H), 2.57 (s, 3H), 6.45 ( d, 1H), 6.82(d, 1H), 6.93-6.99 (m, 5H), 7.04-7.05 (m, 5H), 7.17(s, 1H), 7.24-7.27 (m, 2H), 7.31(d, 1H), 7.35-7.39 (m, 2H), 7.43-7.55 (m, 8H), 7.65(d, 1H), 8.11(s, 1H), 8.31(d, 1H), 8.39(s, 1H), 8.57 (d, 1H), 8.60–8.62 (m, 2H), 10.08 (s, 1H).

<<Production and evaluation of vapor deposition type organic EL devices>>

Fabrication of organic EL device

The following organic EL device was manufactured using the polycyclic aromatic compound manufactured in Synthesis Example.

<Examples 1-1 to 23, Comparative Examples 1-1, Examples 2-1 to 23, Comparative Examples 2-1, Examples 3-1 to 23, Comparative Examples 3-1>

[Comparative Example 1-1]

A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by Opto Science Co., Ltd.) obtained by polishing ITO film formed to a thickness of 200 nm by sputtering to 120 nm was used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available evaporation device (manufactured by Showa Vacuum Co., Ltd.), and HAT-CN, HTL-1, TcTa, ETL-1, new-DABNA, and ET7 were respectively inserted. An evaporation boat, a tungsten evaporation boat each containing LiF and aluminum was installed.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The vacuum chamber was depressurized to 5×10 ^-4 Pa, and first, HAT-CN was heated and deposited to a film thickness of 5 nm to form a hole injection layer. Next, HTL-1 was heated and deposited to a film thickness of 90 nm to form a hole transport layer 1, and TcTa was heated and deposited to a film thickness of 10 nm to form a hole transport layer 2. Next, TcTa, ETL-1, and new-DABNA were simultaneously heated and deposited to a film thickness of 20 nm to form a light emitting layer. The deposition rate was adjusted so that the mass ratio of TcTa, ETL-1, and new-DABNA was about 49.5:49.5:1. Next, ETL-1 was heated and deposited to a film thickness of 20 nm to form an electron transport layer 1, and ET7 was heated and deposited to a film thickness of 10 nm to form an electron transport layer 2. The deposition rate of each layer was 0.01 to 1 nm/sec. After that, LiF was heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec to a film thickness of 1 nm, followed by heating and depositing aluminum to a film thickness of 100 nm to form a cathode, thereby obtaining an organic EL device. At this time, the deposition rate of aluminum was adjusted to be 1 to 10 nm/sec.

[Examples 1-1 to 23, Examples 2-1 to 23, Comparative Examples 2-1, Examples 3-1 to 23 and Comparative Examples 3-1]

ETL-1 (Host) of Comparative Example 1-1 was TcTa and ETL-1 (Host 1 and Host 2) listed in Table 1, and new-DABNA was added to the emitting dopant, or assisting dopant and Examples 1-1 to 23, Examples 2-1 to 23, Comparative Example 2-1, Examples 3-1 to 23 and Comparative Examples in the same order as Comparative Example 1-1 except for changing to the ting dopant. The organic EL element of 3-1 was obtained.

On the other hand, in Table 1, "Host 1" corresponds to a hole-transporting host material, and "Host 2" corresponds to an electron-transporting host material.

The chemical structures of the compounds used in the manufacture of the above elements are shown below.

Evaluation items and evaluation method

Evaluation items include driving voltage (V), emission wavelength (nm), CIE chromaticity (x, y), external quantum efficiency (%), maximum wavelength of emission spectrum (nm) and full width at half maximum (nm). For this evaluation item, for example, a value at the time of 1000 cd/m ² light emission can be used.

The quantum efficiency of a light emitting device includes internal quantum efficiency and external quantum efficiency. The internal quantum efficiency represents the rate at which external energy injected as electrons (or holes) into the light emitting layer of the light emitting device is purely converted into photons. On the other hand, the external quantum efficiency is calculated based on the amount of these photons emitted to the outside of the light emitting element, and photons generated in the light emitting layer are partially absorbed or continuously reflected inside the light emitting element, so that the light emitting element Since it is not emitted to the outside, the external quantum efficiency is lower than the internal quantum efficiency.

The method for measuring spectral radiance (emission spectrum) and external quantum efficiency is as follows. Using a voltage/current generator R6144 manufactured by Advantist, a voltage such that the luminance of the element is 1000 cd/m ² is applied to cause the element to emit light. The spectral emission luminance in the visible region was measured in a direction perpendicular to the light emitting surface using a spectroscopic emission luminance meter SR-3AR manufactured by TOPCON. Assuming that the light emitting surface is a completely diffusive surface, the measured spectral radiance value of each wavelength component divided by the wavelength energy and multiplied by π is the number of photons at each wavelength. Next, the number of photons in the observed full-wave field region is integrated, and the total number of photons emitted from the device is taken. The value obtained by dividing the applied current value by the fundamental charge is the number of carriers injected into the device, and the value obtained by dividing the total number of photons emitted from the device by the number of carriers injected into the device is the external quantum efficiency. In addition, the half width of the emission spectrum is obtained as the width between the upper and lower wavelengths at which the intensity is 50% with the maximum emission wavelength as the center.

For the organic EL devices of Examples 1-1 to 23, Examples 2-1 to 23, Examples 3-1 to 23, Comparative Example 1-1, Comparative Example 2-1, and Comparative Example 3-1, ITO Direct current voltage was applied as ^the electrode as the anode and the LiF/aluminum electrode as the cathode, and the maximum emission wavelength (EL), external quantum efficiency (EQE) and LT80 (at the initial luminance of 1000 cd/m ^{2 )} The time until it reached 800 cd/m ² when continuously driven at a current density of ) was measured.

Table 2 shows the evaluation results of each element.

From the comparison with Comparative Examples, it can be seen that the organic EL element using the polycyclic aromatic compound having the structure represented by formula (1) provides high-efficiency green light emission and at the same time has a long lifespan.

<<Production and evaluation of coating type organic EL device>>

Next, an organic EL element obtained by applying and forming an organic layer will be described.

<Polymer Host Compound: Synthesis of SPH-101>

SPH-101 was synthesized according to the method described in International Publication No. 2015/008851. A copolymer in which M2 or M3 is bonded to the side of M1 is obtained, and it is estimated from the preparation ratio that each unit is 50:26:24 (molar ratio). In the following structural formula, Bpin is pinacolatboril, * is the connection position of each unit.

<Polymer Hole Transport Compound: Synthesis of XLP-101>

XLP-101 was synthesized according to the method described in Japanese Unexamined Patent Publication No. 2018-61028. A copolymer in which M5 or M6 is bonded next to M4 is obtained, and it is estimated from the preparation ratio that each unit is 40:10:50 (molar ratio). Bpin is pinacolatboril, * is the connection position of each unit.

<Preparation of XLP-101 solution>

XLP-101 was dissolved in xylene at a concentration of 0.6% by mass to prepare a 0.6% by mass XLP-101 solution.

<Production of organic EL devices of Examples 4-1 to 4-3>

Table 3 shows the material composition of each layer in the organic EL device.

<Preparation of Compositions (1) to (3) for Forming Light Emitting Layer>

The composition for forming a light emitting layer (1) is prepared by stirring the following components until they become a uniform solution.

Compound (A) 0.02% by mass

2PXZ-TAZ 0.18% by mass

mCBP 1.80% by mass

Toluene 98.00% by mass

A composition for forming a light emitting layer (2) is prepared by stirring the following components until they become a uniform solution.

Compound (A) 0.02% by mass

2PXZ-TAZ 0.18% by mass

SPH-1011.80% by mass

Xylene 98.00% by mass

The composition for forming a light emitting layer (3) is prepared by stirring the following components until they become a uniform solution.

Compound (A) 0.02% by mass

2PXZ-TAZ 0.18% by mass

DOBNA 1.80% by mass

Toluene 98.00% by mass

In Table 3, compound (A) is a polyaromatic compound represented by formula (1) (for example, compound (1-1)), and the polyaromatic compound is a monomer (that is, the monomer has a reactive substituent). It is a polymer compound obtained by polymerizing the polymer compound or a polymer cross-linked product obtained by further cross-linking the polymer compound. A polymer compound for obtaining a polymer crosslinked product has a crosslinkable substituent.

"mCBP" is 3,3'-bis(N-carbazolyl)-1,1'-biphenyl, and "DOBNA" is 3,11-di-o-tolyl-5,9-dioxa-13b- Boranaphtho[3,2,1-di]anthracene, "TSPO1" is diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide, "2PXZ-TAZ" is 10,10'-((4 -phenyl-4H-1,2,4-triazole-3,5-diyl)bis(4,1-phenylene))bis(10H-phenoxazine). The chemical structure is shown below.

<Example 4-1>

After spin-coating a solution of ND-3202 (manufactured by Nissan Chemical Industries, Ltd.) on a glass substrate on which ITO was formed to a thickness of 45 nm, heating at 50 ° C. for 3 minutes in an atmospheric atmosphere, and further heating at 230 ° C. for 15 minutes, An ND-3202 film with a film thickness of 50 nm is formed (hole injection layer). Next, the XLP-101 solution is spin-coated and heated on a hot plate at 200 DEG C for 30 minutes in a nitrogen gas atmosphere to form an XLP-101 film with a thickness of 20 nm (hole transport layer). Then, the composition for forming a light-emitting layer (1) is spin-coated and heated at 130 DEG C for 10 minutes in a nitrogen gas atmosphere to form a 20 nm light-emitting layer.

The produced multilayer film is fixed to a substrate holder of a commercially available evaporation device (manufactured by Showa Vacuum Co., Ltd.), and a molybdenum evaporation boat containing TSPO1, a molybdenum evaporation boat containing LiF, and a tungsten evaporation boat containing aluminum mount the boat After depressurizing the vacuum chamber to 5×10 ^-4 Pa, TSPO1 is heated and evaporated to a film thickness of 30 nm to form an electron transport layer. The deposition rate at the time of forming the electron transport layer is set to 1 nm/sec. After that, LiF is heated and deposited at a deposition rate of 0.01 to 0.1 nm/sec so that the film thickness is 1 nm. Next, aluminum is heated and deposited to a film thickness of 100 nm to form a cathode. In this way, an organic EL element is obtained.

<Example 4-2>

Each, using the composition for forming a light emitting layer (2), an organic EL element is obtained in the same manner as in Example 4-1.

<Example 4-3>

Each, using the composition for forming a light emitting layer (3), an organic EL element is obtained in the same manner as in Example 4-1.

<Evaluation of organic EL devices of Examples 4-1 to 4-3>

The coating type organic EL device obtained as described above can be expected to have excellent driving voltage and external quantum efficiency similarly to the vapor deposition type organic EL device.

100 organic electroluminescent device
101 substrate
102 anode
103 hole injection layer
104 hole transport layer
105 light emitting layer
106 electron transport layer
107 electron injection layer
108 Cathode

Claims (14)

An organic electroluminescent device having a pair of electrodes composed of an anode and a cathode, and a light emitting layer disposed between the pair of electrodes,
The light emitting layer includes at least two selected from the group consisting of an emitting dopant, a hole transporting host material, an electron transporting host material, and an assisting dopant,
The polycyclic aromatic compound represented by formula (1), a polymer compound obtained by polymerizing the polycyclic aromatic compound as a monomer, a polymer crosslinked product obtained by further crosslinking the polymer compound, and the polycyclic aromatic compound having a main chain shape An organic electroluminescent device comprising at least one selected from the group consisting of a pendant-type polymer compound reacted with a polymer and a pendant-type polymer crosslinked product obtained by further crosslinking the pendant-type polymer compound;

In formula (1),
A ring, B ring, D ring, E ring, F ring, and G ring are each independently a substituted or unsubstituted aryl ring or a substituted or unsubstituted heteroaryl ring,
Z is -C(-R ^Z )= or -N=;
R ^Z is each independently hydrogen or a substituent,
Y is each independently B, P, P=O, or P=S;
X is each independently >NR ^NX , >O, >C(-R ^CX ) ₂ , >Si(-R ^IX ) ₂ , >S, or >Se, and R ^NX is hydrogen, substituted or unsubstituted aryl , substituted or unsubstituted heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, and R ^CX and R ^IX are each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted hetero Aryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, two R ^CX may be bonded to each other to form a ring, and two R ^IX may be bonded to each other to form a ring, R ^NX , R ^CX , and R ^IX may each be bonded to one or two rings to which X containing itself bonds through a single bond or a linking group;
At least one selected from the group consisting of an aryl ring and a heteroaryl ring in the structure represented by formula (1) may be condensed with at least one cycloalkane, and the cycloalkane is substituted with at least one substituent may be present, and at least one -CH ₂ - in the cycloalkane may be substituted with -O-;
An organic electroluminescent element in which at least one hydrogen in the structure represented by formula (1) may be substituted with cyano, halogen, or deuterium. According to claim 1,
an organic electroluminescent element in which formula (1) is represented by formula (1B);

In formula (1B),
Y and X have the same meaning as Y and X in formula (1),
Z has the same meaning as Z in formula (1), provided that when Z in Z = Z is -C (-R ^Z ) =, two R ^Z are bonded to each other to form an aryl ring or a heteroaryl ring The aryl ring or heteroaryl ring formed may each have a substituent, and each of Z=Z is independently >NR, >O, >C(-R) ₂ , >Si(-R) ₂ , It may be >S or >Se, and R in >NR, >C(-R) ₂ , and >Si(-R) ₂ is each independently hydrogen, substituted or unsubstituted aryl, substituted or unsubstituted of heteroaryl, substituted or unsubstituted alkyl, or substituted or unsubstituted cycloalkyl, wherein the >C(-R) ₂ and the >Si(-R) ₂ of 2 R are bonded to each other to form a ring, may be,
In the structure represented by formula (1B), at least one of the aryl ring or heteroaryl ring may be condensed with at least one cycloalkane, and the cycloalkane may be substituted with at least one substituent. At least one -CH ₂ - in the alkane may be substituted with -O-;
At least one hydrogen in the structure represented by formula (1B) may be substituted with cyano, halogen or deuterium. According to claim 2,
An organic electroluminescent device in which all Z's are -C(-R ^Z )=. According to claim 2 or 3,
An organic electroluminescent device in which each R ^Z is independently hydrogen, alkyl, phenyl which may be substituted with alkyl, diphenylamino which may be substituted with alkyl, or carbazolyl which may be substituted with alkyl. According to any one of claims 1 to 4,
An organic electroluminescent device in which X is >O, >NR ^NX , or >S. According to claim 1,
An organic electroluminescent device in which the polyaromatic compound represented by Formula (1) is represented by any one of the following formulas;



In the formula, Me is methyl and tBu is t-butyl. According to any one of claims 1 to 6,
An organic electroluminescent device comprising a polycyclic aromatic compound represented by formula (1) as the emitting dopant. According to any one of claims 1 to 6,
A polymer compound obtained by polymerizing the polyaromatic compound represented by formula (1) as a monomer, a polymer crosslinked product obtained by further crosslinking the polymer compound, and a pendant obtained by reacting the polycyclic aromatic compound with a main chain polymer. An organic electroluminescent device comprising at least one selected from the group consisting of a type polymer compound and a pendant type polymer crosslinked product obtained by further crosslinking the pendant type polymer compound. According to any one of claims 1 to 8,
The organic electroluminescent element in which the light-emitting layer contains both the hole-transporting host material and the electron-transporting host material. According to any one of claims 1 to 9,
The hole-transporting host material is represented by formula (HH-1) or has a partial structure represented by formula (HH-1) and contains at least three rings selected from the group consisting of aryl rings and heteroaryl rings It is a compound having a structure,
The electron-transporting host material has a partial structure represented by any one of formulas (EH-1A) to (EH-1D) or formulas (EH-1A) to (EH-1D), and an aryl ring And a compound having a structure containing at least three rings selected from the group consisting of heteroaryl rings, or a polyaromatic compound represented by formula (EH-1b), or having a plurality of structures represented by formula (EH-1b) below. Polycyclic aromatic compounds, organic electroluminescent elements;

In formula (HH-1),
Q is >O, >S, or >NA ^H ;
One carbon atom next to the carbon atom to which Q is bonded in each of the two phenyls in the formula (HH-1) may be bonded to each other by L,
L is a single bond, >O, >S, or >C(-A ^H ) ₂ ,
A ^H is hydrogen, aryl, or heteroaryl, and two A ^Hs in >C(-A ^H ) ₂ may be bonded to each other;

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

In Formula (EH-1b),
R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each independently hydrogen or a substituent;
X ¹ and X ² are each independently >NR ^NX2 , >O, >C(-R ^CX2 ) ₂ , >S, or >Se, and X ¹ and X ² are both >C(-R ^CX2 ) ₂ There is no case where this
R ^NX2 and R ^CX2 are each independently hydrogen or a substituent, and R ^NX2 and R ^CX2 each independently may be bonded to at least one of the a, b and c rings via a linking group or a single bond,
Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , and Y ⁶ are each independently =C(-R ^Y )- or =N-, and at least one is =N-;
R ^Y is each independently hydrogen or a substituent;
Adjacent groups among R ¹ , R ² , R ³ , R ⁴ , and R ⁵ , and R ^Y are bonded to each other to form an aryl ring or a heteroaryl ring together with at least one ring of ring a, ring b, and ring c; It may be present, and at least one hydrogen in the formed ring is aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, diarylboryl (even if two aryls are bonded through a single bond or a linking group) ), may be substituted with alkyl, cycloalkyl, alkoxy, or aryloxy, and at least one hydrogen in these may be further substituted with aryl, heteroaryl, alkyl or cycloalkyl,
At least one hydrogen in the compound and structure represented by formula (EH-1b) may be substituted with cyano, halogen or deuterium. According to claim 10,
The organic electroluminescent device, wherein the hole-transporting host material is HH-1-12 and the electron-transporting host material is EH-1-94.
According to any one of claims 1 to 11,
The organic electroluminescent device, wherein the light emitting layer includes a compound capable of emitting thermally activated delayed fluorescence as the assisting dopant. According to any one of claims 1 to 11,
The organic electroluminescent device, wherein the light emitting layer contains a compound capable of emitting phosphorescence as the assisting dopant. A display device or lighting device comprising the organic electroluminescent device according to any one of claims 1 to 13.