WO2020040298A1

WO2020040298A1 - Organic electroluminescent element, display device, illumination device, luminescent layer forming composition, and compound

Info

Publication number: WO2020040298A1
Application number: PCT/JP2019/033069
Authority: WO
Inventors: 琢次畠山; 靖宏近藤; 笹田　康幸; 梁井　元樹
Original assignee: 学校法人関西学院; Jnc株式会社
Priority date: 2018-08-23
Filing date: 2019-08-23
Publication date: 2020-02-27
Also published as: CN113169285A; JPWO2020040298A1; KR20210050537A; JP7388658B2

Abstract

Disclosed is an organic electroluminescent element having a luminescent layer that comprises a host compound as a first component, a thermally-activated delayed fluorescence substance as a second component, and a boron-atom-containing compound as a third component, wherein the following relational formula is satisfied: (Excited singlet energy level determined from shoulder on peak short wavelength side of fluorescence spectrum of first component)≥(Excited singlet energy level determined from shoulder on peak short wavelength side of fluorescence spectrum of second component)≥(Excited singlet energy level determined from shoulder on peak short wavelength side of fluorescence spectrum of third component).

Description

Organic electroluminescent device, display device, lighting device, composition for forming light emitting layer, and compound

The present invention relates to an organic electroluminescent device including a host compound, a thermally activated delayed phosphor and a compound having a boron atom, and a display device and a lighting device including the organic electroluminescent device. The present invention also relates to a composition and a compound for forming a light emitting layer of an organic electroluminescent device.

2. Description of the Related Art Conventionally, a display device using a light emitting element that emits electroluminescence has been studied variously because power saving and thinning are possible. Further, an organic electroluminescence element (organic EL element) made of an organic material has been reduced in weight and It has been actively studied because it is easy to increase the size. In particular, regarding the development of organic materials having light-emitting properties such as blue, which is one of the three primary colors of light, and the development of organic materials having charge-transporting capabilities such as holes and electrons, high-molecular compounds and low-molecular compounds were developed. Regardless, it has been actively researched so far.

The organic electroluminescent element has a structure including a pair of electrodes including an anode and a cathode, and one or more layers including an organic compound disposed between the pair of electrodes. Examples of the layer containing an organic compound include a light-emitting layer and a charge transport / injection layer that transports or injects charges such as holes and electrons. Various organic materials suitable for these layers have been developed.

発光 There are mainly two light emission mechanisms of the organic electroluminescent element: fluorescence emission using light emission from an excited singlet state and phosphorescence emission using light emission from an excited triplet state. Common fluorescent light emitting materials have low exciton utilization efficiency, about 25%, and have triplet-triplet fusion (TTF: Triplet-Triplet @ Fusion or triplet-triplet annihilation, TTA: Triplet-Triplet @ Annihilation). ), The exciton utilization efficiency is 62.5%. On the other hand, phosphorescent materials may have an exciton utilization efficiency of 100% in some cases, but have difficulty in achieving deep blue light emission, and have a problem that the color purity is low due to the wide emission spectrum.

To address this, Professor Chihaya Adachi of Kyushu University proposed a thermally activated delayed fluorescent (TADF) mechanism (see Non-Patent Document 1), and the use of a thermally activated delayed fluorescent substance to emit light. The exciton utilization efficiency has reached 100%. Although the heat-activated delayed fluorescent substance gives a broad emission spectrum with low color purity due to its structure, the speed of inverse intersystem crossing is extremely high.

In addition, Adachi and colleagues take advantage of this advantage, using thermally activated delayed phosphors as assisting dopants (Assisting Dopant: AD), and using narrow half bandwidth dopants as emitting dopants (Emitting Dopant: ED). Hyper Fluorescence ^™ (TADF Assisting Fluorescence: also called TAF) has been proposed, and a high-efficiency, high-color-purity, and long-life element has been developed as a red- and green-emitting organic electroluminescent element (see Non-Patent Document 2). However, deep blue emission has problems in any of efficiency, color purity, and lifetime because both the emitting dopant and the assisting dopant require high energy.

Therefore, a new molecular design that dramatically improves the color purity of TADF materials has been proposed by Professor Kwansei Gakuin University Hatakeyama (see Non-Patent Document 3). In Patent Document 1, for example, the compound (1-401) disclosed has a robust planar structure utilizing the multiple resonance effect of boron (electron donating) and nitrogen (electron withdrawing), resulting in absorption and emission. Successfully obtained an emission spectrum having a small Stokes shift and a high color purity. In the dimer compound represented by the formula (1-422), two borons and two nitrogens are bonded to the central benzene ring, so that the multiple resonance effect is further enhanced in the central benzene ring. As a result, it is possible to emit light having an extremely narrow emission peak width.

International Publication No.2015 / 102118

As described above, various materials have been developed as materials used for the organic electroluminescent element. However, organic electroluminescent properties such as luminescent properties are further enhanced, and options of organic electroluminescent materials such as a material for a light emitting layer are increased. In order to increase the number, combinations of compounds that have not been specifically known hitherto are desired.

The present inventors have conducted intensive studies to solve the above problems, and as a result, using a host compound, a thermally activated delayed fluorescent substance, and a light emitting layer containing a compound having a boron atom in a molecule, their excited singlet energy levels It has been found that by defining the positional relationship, an excellent organic electroluminescent device can be obtained, and the present invention has been completed. Specifically, the present invention has the following configuration.

[1]
An organic electroluminescent device having a light emitting layer, wherein the light emitting layer is
As a first component, at least one host compound;
As a second component, at least one heat-activated delayed phosphor;
A compound having at least one type of boron atom as the third component,
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the first component is E (1, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component. The excited singlet energy level is E (2, S, Sh), and the excited singlet energy level determined from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the third component is E (3, S, Sh). When the following relational expression (1) is satisfied,
The first component may be included as a polymer compound having a structure in which two hydrogen atoms of the host compound are eliminated as a repeating unit,
The second component may be included as a polymer compound having a structure in which two hydrogen atoms of the thermally activated delayed fluorescent substance are eliminated as a repeating unit,
The third component may be included as a polymer compound having a structure in which two hydrogen atoms of the compound having a boron atom are eliminated as a repeating unit,
Organic electroluminescent device.
Relational expression (1): E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh)
[2]
As the third component, at least one of a compound represented by any of the following formulas (i), (ii) and (iii) and a multimeric compound having a plurality of structures represented by the following formula (i): The organic electroluminescent device according to [1].

(In the above formula (i),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y ¹ Is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X ¹ And X ² Is independently O, NR,> CR ₂ , S or Se, R of the NR and> CR ₂ R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted cycloalkyl or alkyl, and R of the above NR is a linking group or a single bond. , B and C may be bonded to at least one selected from the group consisting of
At least one hydrogen in the compound or structure represented by formula (i) may be replaced with cyano, halogen, or deuterium. )

(In the above formula (ii),
A ring, B ring, C ring and D ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y is B (boron),
X ¹ , X ² , X ³ And X ⁴ Are independently>O,>NR,> CR ₂ ,> S or> Se, and the R of> NR and> CR ₂ R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted cycloalkyl or an optionally substituted alkyl; May be bonded to at least one selected from the A ring, B ring, C ring and D ring by a group or a single bond,
R ¹ And R ² Is independently hydrogen, alkyl having 1 to 6 carbons, cycloalkyl having 3 to 12 carbons, aryl having 6 to 12 carbons, heteroaryl having 2 to 15 carbons or diarylamino (where aryl is carbon Aryl of formulas 6 to 12)
At least one hydrogen in the compound represented by the formula (ii) may be substituted with cyano, halogen, or deuterium. )

(In the above formula (iii),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y ¹ Is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X ¹ , X ² And X ³ Is independently O, NR,> CR ₂ , S or Se, R of the NR and> CR ₂ R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted cycloalkyl or alkyl, and R of the above NR is a linking group or a single bond. , B and C may be bonded to at least one selected from the group consisting of
At least one hydrogen in the compound or structure represented by formula (iii) may be substituted with cyano, halogen, or deuterium. )
[3]
The organic electroluminescence according to [1] or [2], wherein the third component contains at least one compound represented by any of the following formulas (1), (2), (3) and (4). element.

(In the above formula (1),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ And R ¹¹ Is each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy, which may be further substituted with aryl, heteroaryl or alkyl; , R ¹ ~ R ³ , R ⁴ ~ R ⁷ And R ⁸ ~ R ¹¹ May be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring is aryl, heteroaryl, diarylamino, alkyl, cyclo May be substituted with at least one selected from alkyl, alkoxy and aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl;
X ¹ And X ² Is independently>O,> NR or> CR ₂ R of the above-mentioned —N—R and> CR ₂ R is aryl, heteroaryl, cycloalkyl or alkyl, which may be substituted with at least one selected from aryl, heteroaryl, cycloalkyl and alkyl;
Where X ¹ And X ² Is simultaneously> CR ₂ Will not be
And
At least one hydrogen in the compounds and structures represented by formula (1) may be substituted with cyano, halogen or deuterium. )

(In the above formula (2),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ And R ¹⁴ Is each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio or An alkyl-substituted silyl wherein at least one hydrogen is optionally substituted with aryl, heteroaryl or alkyl; ⁵ ~ R ⁷ And R ¹⁰ ~ R ¹² And adjacent groups may form an aryl ring or a heteroaryl ring together with the b-ring or the d-ring, and at least one hydrogen in the formed ring is aryl, heteroaryl, diarylamino, Diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio or alkyl-substituted silyls, wherein at least one hydrogen is aryl May be substituted with heteroaryl or alkyl;
Y is B (boron),
X ¹ , X ² , X ³ And X ⁴ Is independently>O,> NR or> CR ₂ R of the above-mentioned —N—R and> CR ₂ Is an aryl having 6 to 12 carbons, a heteroaryl having 2 to 15 carbons, a cycloalkyl having 3 to 12 carbons or an alkyl having 1 to 6 carbons. > CR ₂ R is -O-, -S-, -C (-R) ₂ -Or a single bond may be bonded to at least one selected from the a ring, the b ring, the c ring and the d ring; ₂ R in-is hydrogen or alkyl having 1 to 6 carbons,
Where X ¹ , X ² , X ³ , And X ⁴ Is simultaneously> CR ₂ Will not be
And
At least one hydrogen in the compound represented by the formula (2) may be substituted with cyano, halogen, or deuterium. )

(In the above formula (3),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁹ , R ¹⁰ And R ¹¹ Is each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy, which are further substituted with at least one selected from aryl, heteroaryl and alkyl And R ¹ ~ R ³ , R ⁴ ~ R ⁶ And R ⁹ ~ R ¹¹ May be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring is aryl, heteroaryl, diarylamino, alkyl, cyclo May be substituted with at least one selected from alkyl, alkoxy and aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl, cycloalkyl and alkyl;
X ¹ , X ² And X ³ Independently represent>O,> NR, or> CR ₂ R of the above-mentioned —N—R and> CR ₂ R is aryl, heteroaryl, cycloalkyl or alkyl, which may be substituted with at least one selected from aryl, heteroaryl and alkyl;
Where X ¹ , X ² , And X ³ Is simultaneously> CR ₂ Will not be
And
At least one hydrogen in the compounds and structures represented by formula (3) may be substituted with cyano, halogen or deuterium. )

(In the above formula (4),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ And R ¹⁴ Is each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy, which are further substituted with at least one selected from aryl, heteroaryl and alkyl And R ¹ ~ R ³ , R ⁴ ~ R ⁷ , R ⁸ ~ R ¹⁰ And R ¹¹ ~ R ¹⁴ Among adjacent groups may be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, the b ring, the c ring or the d ring, and the formed ring is aryl, heteroaryl, diarylamino, Optionally substituted with at least one selected from alkyl, cycloalkyl, alkoxy and aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl;
X is>O,> NR or> CR ₂ R of the above-mentioned —N—R and> CR ₂ R is aryl, heteroaryl or alkyl, which may be substituted with at least one selected from aryl, heteroaryl and alkyl;
L is a single bond,> CR ₂ ,>O,> S or> NR, and the above> CR ₂ And R in> NR is each independently hydrogen, aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy, which are at least one further selected from aryl, heteroaryl and alkyl. May be substituted,
However, X and L are simultaneously> CR ₂ Will not be
And
At least one hydrogen in the compounds and structures represented by formula (4) may be substituted with cyano, halogen or deuterium. )
[4]
As the third component, at least one compound represented by any of the formulas (1), (2) and (4) is included,
In the above formula (1), X ¹ And X ² Are each independently> O or> NR,
In the above formula (2), X ¹ , X ² , X ³ And X ⁴ Are each independently> O or> NR,
In the above formula (4), X is> O and> NR, and L is a single bond.
The organic electroluminescent device according to [3].
[5]
As the third component, at least one compound represented by any of the formulas (1), (2), (3), and (4) is included, and an atom constituting a ring present in the compound includes: At least one selected from aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl The organic electroluminescent device according to [3] or [4], wherein the organic electroluminescent device is substituted by one.
[6]
As the third component, at least one compound represented by the formula (2) is included, and the atoms constituting the ring present in the compound are aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino , Arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl, which are further substituted with aryl, heteroaryl, cycloalkyl And the organic electroluminescent device according to [5], which may be substituted with at least one selected from alkyl and alkyl.
[7]
The organic electroluminescent device according to any one of [1] to [6], wherein the third component includes a partial structure represented by the following formula. However, each hydrogen in the partial structure may be independently substituted with aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy or aryloxy, and these are further substituted with aryl, heteroaryl, cycloalkyl and alkyl. And may be substituted with at least one selected from

[8]
The organic electroluminescent device according to any one of [3] to [6], wherein the compound represented by any one of the formulas (1) to (4) includes any of the following partial structures. .

(In the above partial structural formula,
Me represents methyl, tBu represents t-butyl, and a wavy line represents a bonding position.
However, hydrogen in the above partial structural formula is
Each independently may be substituted with aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy; the hydrogen in said aryl may be further substituted with aryl, heteroaryl or alkyl; May be further substituted with aryl, heteroaryl or alkyl, and the hydrogen in the diarylamino may be further substituted with aryl, heteroaryl or alkyl. )
[9]
The compound represented by any of the above formulas (1) to (4) is ³ Sp bonded to m or p position with respect to carbon or boron atom ² The organic electroluminescent device according to any one of [3] to [8], which has one of a carbon atom and a nitrogen atom substituted at the p-position with respect to boron.
[10]
The organic electroluminescent device according to [3], wherein the compound represented by the formula (2) is the following compound.

[11]
The organic electroluminescent device according to [4], wherein the compound represented by the formula (2) is the following compound.

[12]
The organic electroluminescent device according to any one of [1] to [11], wherein the first component is a compound having, as a partial structure, at least one selected from carbazole and furan.
[13]
The organic material according to any one of [1] to [12], wherein the first component contains at least one compound represented by any of the following formulas (H1), (H2) and (H3). Electroluminescent device.

(In the above formulas (H1), (H2) and (H3), L ¹ Is arylene, heteroarylene, heteroarylenearylene or aryleneheteroarylenearylene having 6 to 24 carbon atoms;
At least one hydrogen in the compounds represented by each of the above formulas may be substituted with alkyl having 1 to 6 carbon atoms, cyano, halogen or deuterium. )
[14]
The second component is selected from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole, oxadiazole, thiadiazole and benzophenone as a partial structure. The organic electroluminescent device according to any one of [1] to [13], comprising at least one of the following:
[15]
The organic compound according to any one of [1] to [14], wherein the second component contains at least one compound represented by any of the following formulas (AD1), (AD2) and (AD3). Electroluminescent device.

(In the above formulas (AD1), (AD2) and (AD3),
M is each independently a single bond, —O—,> N—Ar or> CAr ₂ And
J is each independently an arylene having 6 to 18 carbon atoms, and the arylene is substituted with at least one selected from phenyl, alkyl having 1 to 6 carbons, and cycloalkyl having 3 to 12 carbons. May be
Q is each independently = C (-H)-or = N-;
Ar is each independently hydrogen, aryl having 6 to 18 carbons, heteroaryl having 6 to 18 carbons, alkyl having 1 to 6 carbons or cycloalkyl having 3 to 12 carbons, At least one hydrogen in the arylene may be substituted with phenyl, alkyl having 1 to 6 carbons or cycloalkyl having 3 to 12 carbons,
m is 1 or 2,
n is an integer of 2 to (6-m);
At least one hydrogen in the compounds represented by the above formulas may be substituted with halogen or deuterium. )
[16]
The organic electroluminescent device according to any one of [1] to [14], wherein the second component contains at least one compound represented by the following formula (DAD1).
(D ¹ -L ¹ ) NA ¹ (DAD1)
(In the above formula (DAD1), D ¹ Is a donor group, L ¹ Is a single bond or a conjugated linking group; ¹ Is an acceptor group, n is 2 or more and A ¹ Is an integer less than or equal to the maximum number that can be substituted. )
[17]
The organic electroluminescent device according to [16], wherein the second component contains at least one compound represented by the following formula (DAD2).
D ² -L ² -A ² -L ³ -D ³ (DAD2)
(In the above formula (DAD2), D ² And D ³ Are each independently a donor group, and L ² And L ³ Are each independently a single bond or a conjugated linking group; ² Is an acceptor group. )
[18]
In the above formulas (AD1), (AD2) and (AD3),
M is each independently a single bond, —O— or>N—Ar;
J is each independently phenylene, and the phenylene may be substituted with alkyl having 1 to 4 carbon atoms;
Q is each independently = N-,
Ar is each independently hydrogen or phenyl, and the phenyl may be substituted with phenyl or alkyl having 1 to 4 carbons;
m is 1 or 2,
n is an integer of 4 to (6-m);
The organic electroluminescent device according to [17].
[19]
When the inverse intersystem crossing speed of the second component is 10 ⁵ s ^-1 The organic electroluminescent device according to any one of [1] to [18], which is as described above.
[20]
The organic electroluminescent device according to any one of [1] to [19], wherein the delayed fluorescence lifetime of the third component is 0.05 μsec to 40 μsec.
[21]
The organic electroluminescent device according to any one of [1] to [19], wherein the delayed fluorescence lifetime of the third component is 0.05 μsec to 20 μsec.
[22]
The organic electroluminescent device according to any one of [1] to [21], wherein a Stokes shift obtained from a difference between a peak top of a fluorescence spectrum and a peak top of an absorption spectrum of the third component is 14 nm or less.
[23]
The organic electroluminescent device according to any one of [1] to [21], wherein the Stokes shift obtained from the difference between the peak top of the fluorescence spectrum and the peak top of the absorption spectrum of the third component is 10 nm or less.
[24]
The excitation singlet energy level obtained from the shoulder on the peak short wavelength side of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the peak short wavelength side of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). Assuming that the excited triplet energy level determined from the shoulder on the peak short wavelength side of the phosphorescence spectrum of the third component is E (3, T, Sh), the singlet triplet energy difference (ΔE (2, The organic electroluminescent device according to any one of [1] to [23], wherein ST, Sh) and ΔE (3, ST, Sh)) have the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.50 eV
ΔE (3, ST, Sh) = E (3, S, Sh) −E (3, T, Sh) ≦ 0.20 eV
[25]
The excitation singlet energy level obtained from the shoulder on the peak short wavelength side of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the peak short wavelength side of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), and the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). When the excited triplet energy level obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the third component is E (3, T, Sh), the singlet triplet energy difference (ΔE (2, The organic electroluminescent device according to any one of [1] to [24], wherein ST, Sh) and ΔE (3, ST, Sh)) have the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh)
ΔE (3, ST, Sh) = E (3, S, Sh) -E (3, T, Sh)
ΔE (2, ST, Sh) ≧ ΔE (3, ST, Sh)
[26]
The organic electroluminescent device according to any one of [1] to [25], wherein a singlet / triplet energy difference (ΔE (2, ST, Sh)) of the second component has the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.30 eV
[27]
The organic electroluminescent device according to any one of [1] to [26], wherein a singlet / triplet energy difference (ΔE (2, ST, Sh)) of the second component has the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.15 eV
[28]
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). When the excited triplet energy level obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the third component is E (3, T, Sh), these have the following relationships, [1] to [27]. The organic electroluminescent device according to any one of the above.
E (2, S, Sh) ≧ E (3, S, Sh)
E (2, T, Sh) ≦ E (3, T, Sh)
[29]
The organic electroluminescent device according to any one of [1] to [28], wherein a Stokes shift obtained from a difference between a peak top of a fluorescence spectrum and a peak top of an absorption spectrum of the third component is 10 nm or less.
[30]
The device according to any one of [1] to [29], wherein the third component is contained as a polymer compound having a repeating unit of a group having two hydrogen atoms eliminated from the compound having a boron atom. Organic electroluminescent device.
[31]
The polymer according to [30], wherein the polymer compound having a group from which two hydrogen atoms have been eliminated in the compound having a boron atom as a repeating unit also has a group in which two hydrogen atoms have been eliminated from the host compound as a repeating unit. Organic electroluminescent device.
[32]
The polymer compound having a group in which two hydrogen atoms have been eliminated from the compound having a boron atom as a repeating unit, the polymer compound having a group in which two hydrogen atoms have been eliminated from the delayed fluorescent substance also has a repeating unit, [30] or The organic electroluminescent device according to [31].
[33]
A display device comprising the organic electroluminescent device according to any one of [1] to [32].
[34]
A lighting device comprising the organic electroluminescent element according to any one of [1] to [32].
[35]
A composition for forming a light-emitting layer for coating and forming a light-emitting layer of an organic electroluminescent device,
A composition for forming a light emitting layer, comprising at least one organic solvent as a fourth component in addition to the first component, the second component, and the third component according to any one of [1] to [32]. (However, the third component is not the following compound.)

[36]
The composition for forming a light emitting layer according to [35], wherein a boiling point of at least one organic solvent in the fourth component is from 130 ° C. to 350 ° C.
[37]
The fourth component includes a good solvent (GS) and a poor solvent (PS) for at least one of the first component, the second component, and the compound that is the third component, and the good solvent (GS) Boiling point (BP _GS ) Is the boiling point (BP) of the poor solvent (PS) _PS The composition for forming a light-emitting layer according to [35] or [36], wherein the composition is lower than (3).
[38]
The first component is 0.0998% by mass to 4.0% by mass with respect to the total mass of the composition for forming a light emitting layer;
0.0001% by mass to 2.0% by mass of the second component based on the total mass of the composition for forming a light emitting layer;
The third component is 0.0001% by mass to 2.0% by mass based on the total mass of the composition for forming a light emitting layer;
90.0% by mass to 99.9% by mass of the fourth component, based on the total mass of the composition for forming a light emitting layer;
The composition for forming a light emitting layer according to any one of [35] to [37].
[39]
[35] An organic electroluminescent device having a light emitting layer formed using the composition for forming a light emitting layer according to any one of [38] to [38].
[40]
A compound in which at least one hydrogen of the compound represented by the formula (ii) according to [2] is substituted by the following partial structure (B), chlorine, bromine, or iodine.

(In the above partial structure (B), R ⁴⁰ And R ⁴¹ Is an alkyl having 2 to 10 carbon atoms which may be bonded, and the wavy line is a bonding site to another structure. )
[41]
A repeating unit containing a structure in which two hydrogen atoms are eliminated from a compound having a boron atom, a repeating unit containing a structure in which two hydrogen atoms are eliminated from a thermally activated delayed fluorescent substance, and two hydrogen atoms from a host compound A polymer compound comprising at least two kinds of repeating units selected from repeating units having a structure from which is eliminated.
[42]
At least one kind of repeating unit containing a structure in which two hydrogen atoms are eliminated from a compound having a boron atom, at least one kind of repeating unit containing a structure in which two hydrogen atoms are eliminated from a thermally activated delayed fluorescent substance, And a polymer compound containing at least one repeating unit having a structure in which two hydrogen atoms are eliminated from a host compound.

The organic electroluminescent device of the present invention includes, in the light-emitting layer, a host compound, a heat-activated delayed fluorescent substance, and a compound having a boron atom in a molecule, and their excited singlet energy levels satisfy a predetermined condition. Thereby, the organic electroluminescence characteristics can be further enhanced.

FIG. 2 is an energy level diagram showing an example of an energy relationship between a host, an assisting dopant, and an emitting dopant of the organic electroluminescent device to which the present invention is applied. FIG. 4 is an energy level diagram showing another example of the energy relationship between the host, the assisting dopant, and the emitting dopant of the organic electroluminescent device to which the present invention is applied. FIG. 9 is an energy level diagram showing still another example of the energy relationship between the host, the assisting dopant, and the emitting dopant of the organic electroluminescent device to which the present invention is applied. FIG. 1 is a schematic cross-sectional view illustrating an organic electroluminescent device according to an embodiment. FIG. 4 is an energy level diagram showing an energy relationship among a host, an assisting dopant, and an emitting dopant of a TAF element using a general fluorescent dopant. FIG. 3 is a diagram illustrating a method for manufacturing an organic electroluminescent element on a substrate having a bank by using an inkjet method. FIG. 2 is a view showing the relationship between the basic skeleton of a compound and Tau (Delay) and Stokes shift. FIG. 3 is a diagram showing the relationship between the basic skeleton of a compound and the half-value width, external quantum efficiency, and device lifetime. FIG. 3 is a view showing the relationship between substituents of a compound and Tau (Delay) and Stokes shift. FIG. 3 is a diagram showing the relationship among substituents of a compound and half-value width, external quantum efficiency, and device lifetime. FIG. 3 is a diagram showing the relationship between the substituents of a compound and Stokes shift and half width.

本 Hereinafter, the present invention will be described in detail. The description of the components described below may be made based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In addition, in this specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit. Room temperature means 20 ° C.

1. Explanation of Terms and Mechanism of the Present Invention The organic electroluminescent device of the present invention utilizes a host compound, a thermally activated delayed fluorescent substance, and a compound having a boron atom in a molecule.
The “host compound” in the present invention means that the excited singlet energy level determined from the shoulder on the short wavelength side of the peak of the fluorescence spectrum is a thermally activated delayed phosphor as the second component, and It means a compound higher than a compound having a boron atom.
The term "thermally activated delayed phosphor" refers to the absorption of thermal energy, which causes an inverse intersystem crossing from an excited triplet state to an excited singlet state, and radiation inactivation from the excited singlet state to cause delayed fluorescence. It means a compound that can emit. However, the term “thermally activated delayed fluorescence” includes those that undergo higher-order triplets in the process of excitation from the excited triplet state to the excited singlet state. For example, a paper by Durk University Monkman et al. (NATURE COMMUNICATIONS, 7: 13680, DOI: 10.1038 / ncomms13680), a paper by Hosogai et al. Sato et al. (Scientific Reports, 7: 4820, DOI: 10.1038 / s41598-017-05007-7) and Sato et al. At Kyoto University (The 98th Annual Meeting of the Chemical Society of Japan, publication number: 2I4- 15. Highly efficient light emission mechanism in organic electroluminescence using DABNA as a light-emitting molecule, Kyoto University Graduate School of Engineering). In the present invention, when the fluorescence lifetime of a sample containing a target compound is measured at 300 K, it is determined that the target compound is a “heat-activated delayed fluorescent substance” when a slow fluorescent component is observed. . Here, the slow fluorescent component refers to a component having a fluorescence lifetime of 0.1 μsec or more. The measurement of the fluorescence lifetime can be performed using, for example, a fluorescence lifetime measuring device (C11367-01, manufactured by Hamamatsu Photonics KK).
The `` compound having a boron atom in the molecule '' can function as an emitting dopant, and the `` thermally-activated delayed fluorescent substance '' can be used as an assisting dopant to assist the emission of a compound having a boron atom in the molecule. Can work.
In the following description, an organic electroluminescent device using a thermally activated delayed phosphor as an assisting dopant may be referred to as a “TAF device” (TADF Assisting Fluorescence device).

FIG. 5 shows an energy level diagram of a light emitting layer of a TAF element 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 excited singlet energy level determined from the shoulder on the short wavelength side of the fluorescence spectrum of the host is E (1, S, Sh), The excited triplet energy level determined from the shoulder on the short wavelength side of the phosphorescence spectrum is E (1, T, Sh), and the ground state energy level of the assisting dopant as the second component is E (2, G). , The excitation singlet energy level determined from the short wavelength shoulder of the fluorescence spectrum of the assisting dopant as the second component is E (2, S, Sh), and the phosphorescent spectrum of the assisting dopant as the second component is E (2, S, Sh). The excited triplet energy level determined from the shoulder on the short wavelength side is E (2, T, Sh), the ground state energy level of the emitting dopant as the third component is E (3, G), The excitation singlet energy level determined from the shoulder on the short wavelength side of the fluorescence spectrum of the three-component emitting dopant is E (3, S, Sh), and the short-wavelength of the phosphorescent spectrum of the third component is the dopant. The excited triplet energy level determined from the shoulder on the side is E (3, T, Sh). In a TAF element, when a general fluorescent dopant is used as an emitting dopant (ED), the energy up-converted by the assisting dopant is changed to the excited singlet energy level E (3, S, Sh) of the emitting dopant. The light is shifted. However, some of the excited triplet energy E (2, T, Sh) on the assisting dopant moves to the excited triplet energy level E (3, T, Sh) of the emitting dopant, , An intersystem crossing from the excited singlet energy level E (3, S, Sh) to the excited triplet energy level E (3, T, Sh) occurs, and then heat is transferred to the ground state E (3, G). Deactivate. Some energy is not used for light emission by this route, and energy is wasted.

On the other hand, in the organic electroluminescent device of the present invention, the energy transferred from the assisting dopant to the emitting dopant can be efficiently used for light emission, thereby realizing high luminous efficiency. This is presumed to be due to the following light emission mechanism.
That is, a preferable energy relationship in the organic electroluminescent device of the present invention is shown in FIG. In the organic electroluminescent device of the present invention, the compound having a boron atom as the emitting dopant has a high excited triplet energy level E (3, T, Sh). Therefore, even if the excited singlet energy up-converted by the assisting dopant intersects with the excited triplet energy level E (3, T, Sh) by the emitting dopant, the excited singlet energy remains on the emitting dopant. It is up-converted or recovered to the excited 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 the functions of up-conversion and luminescence into two types of molecules, each of which is excellent, it is expected that the residence time of high energy is reduced and the burden on the compound is reduced.

On the other hand, for the compound containing a boron atom, which is the third component of the present invention, the excited triplet energy involved in the forward and reverse intersystem crossing from the excited triplet state to the excited singlet state is calculated by molecular orbital calculation. Has been pointed out that it may not be the excited triplet energy observed by the phosphorescence spectrum but a higher-order excited triplet energy (The 98th Annual Meeting of the Chemical Society of Japan, Presentation No .: 2I4-15, Mechanism of high-efficiency light emission in organic electroluminescence using DABNA as a light-emitting molecule, presented by Professor Toru Sato of the Graduate School of Engineering, Kyoto University). According to the presentation, the inverse intersystem crossing in DABNA2 having a boron atom in the molecule is an FvHT (Fluorescence via Higher Triplet) mechanism using higher-order triplet orbitals, and the transition from higher-order triplet orbitals to the ground state is performed. It is suggested that the transition from higher-order triplet orbit to excited singlet orbit occurs because of the suppression.

In consideration of the higher-order triplet energy level, the energy relation in the light-emitting layer of the organic electroluminescent device of the present invention is such that the higher-order excited triplet energy level E (3, Tn) is the excited singlet energy level. If it is slightly lower (in the case of the TADF mechanism), it can be represented by the energy level diagram of FIG. 2, and if the higher-order excited triplet energy level is slightly higher than the excited singlet energy level (FvHT function). 3) can be represented by the energy level diagram of FIG. In any case, since deactivation from the lowest triplet orbit is suppressed, it is expected that good device characteristics will be provided similarly to the energy relationship in FIG. However, higher-order triplet orbits suggested by molecular orbital calculations have not been revealed spectroscopically at present. In the present specification, the excited triplet energy level is determined from the phosphorescence spectrum because it can be measured spectroscopically. However, the organic electroluminescent device of the present invention is not limited to those shown in FIGS. It does not exclude having the energy relationship shown by.

From the viewpoint of a TADF-active compound, a DA-type thermally activated delayed phosphor (D represents an electron-donating atomic group and A represents an electron-accepting atomic group) has a high up-conversion rate. , The half-width of light emission is wide, and the color purity is low. On the other hand, a thermally activated delayed phosphor of the multiple resonance effect (MRE) type has a slow up-conversion speed, a narrow emission half width, a high color purity, a high fluorescence quantum yield (PLQY), and It is characterized by a high light emission speed. The organic electroluminescent device of the present invention is designed to take advantage of these molecules. As a result, it is possible to realize a spectrum with a good halftone width and a good color, high external quantum efficiency, improved roll-off, and long life.

From the conditions of the TAF device shown in the paper and the above description, the host compound (first component), the thermally activated delayed phosphor (assisting dopant, second component), and the boron atom in the organic electroluminescent device of the present invention were used. The relationship between the energies of the compounds (emission dopant, third component) is summarized below.

The excitation singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the first component is E (1, S, Sh), and the excitation singlet determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the second component. When the term energy level is E (2, S, Sh) and the excited singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the third component is E (3, S, Sh), Satisfies the relational expression (1).
Relational expression (1): E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh)
That is, confinement and / or transmission of energy is carried out by the host compound as the first component, and light emission is carried by the emitting dopant as the third component.
Here, E (1, S, Sh) -E (2, S, Sh) is preferably from 0 to 1.0 eV, and E (2, S, Sh) -E (3, S, Sh) is It is preferably 0 to 0.20 eV.

The excitation singlet energy level obtained from the short wavelength side peak top of the fluorescence spectrum of the first component is E (1, S, PT), and the excitation singlet energy obtained from the short wavelength side peak top of the second component fluorescence spectrum is obtained. When the term energy level is E (2, S, PT) and the excited singlet energy level obtained from the peak top on the short wavelength side of the fluorescence spectrum of the third component is E (3, S, PT), It is preferable to satisfy the following two relational expressions.
E (1, S, PT)> E (2, S, PT)
E (1, S, PT)> E (3, S, PT)
The present invention can be applied to E (2, S, PT) and E (3, S, PT) whichever is larger, but E (3, S, PT)> E (2, S, PT) It is preferable that

The excitation singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation triplet determined from the shoulder on the peak short wavelength side of the phosphorescence spectrum of the second component. The term energy level is E (2, T, Sh), the excited singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the third component is E (3, S, Sh), and the energy of the third component is Assuming that the excited triplet energy level obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum is E (3, T, Sh), the singlet triplet energy difference (ΔE (2, ST, Sh)) obtained from these is determined. And ΔE (3, ST, Sh)) preferably have the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.50 eV
ΔE (3, ST, Sh) = E (3, S, Sh) −E (3, T, Sh) ≦ 0.20 eV
That is, in the second component, the magnitude of ΔE (ST) is used as an index of TADF activity. The smaller ΔE (ST) is, the more advantageous it is for showing TADF activity.
Here, ΔE (2, ST, Sh) is more preferably 0.30 eV or less, further preferably 0.15 eV or less, and even more preferably 0.10 eV or less. ΔE (3, ST, Sh) is more preferably 0.15 eV or less, and even more preferably 0.10 eV or less.
ΔE (2, ST, Sh) and ΔE (3, ST, Sh) preferably have the following relationship.
ΔE (2, ST, Sh) ≧ ΔE (3, ST, Sh)

It is also preferable that the following relationship be satisfied.
E (2, S, Sh) ≧ E (3, S, Sh)
E (2, T, Sh) ≦ E (3, T, Sh)
Here, E (2, S, Sh) -E (3, S, Sh) is preferably 0 to 0.20 eV, and E (3, T, Sh) -E (2, T, Sh) is It is preferably 0 to 0.20 eV.
These show the design of the TAF element of the present invention shown in FIG.

Also, the inverse intersecting speed of the second component is k (2, RISC), the inverse intersecting speed of the third component is k (3, RISC), the emission speed of the second component is k (2, Prompt) and When the light emission speed of the third component is k (3, Prompt), it is preferable that the following relationship be satisfied.
k (2, RISC)> k (3, RISC)
k (2, Prompt) <k (3, Prompt)

Further, in the present specification, for the host compound, the excitation singlet energy level determined from the shoulder on the short wavelength side of the fluorescence spectrum is E (1, S, Sh), and the peak top on the short wavelength side of the fluorescence spectrum is defined as E (1, S, Sh). The excitation singlet energy level determined from the above is defined as E (1, S, PT), and the excitation triplet energy level determined from the shoulder on the short wavelength side of the phosphorescence spectrum is defined as E (1, T, Sh). The excited triplet energy level determined from the peak top on the short wavelength side of the spectrum is E (1, T, PT). The above E (1, S, Sh), E (2, S, Sh) and E (3, S, Sh) are collectively called E (S, Sh), and E (1, S, PT) ), E (2, S, PT) and E (3, S, PT) are collectively called E (S, PT), E (1, T, Sh), E (2, T, Sh), E (3, T, Sh) is generically called E (T, Sh) and E (1, T, PT), E (2, T, PT), E (3, T, PT) E (T, PT), and ΔE (2, ST, PT) and ΔE (3, ST, PT) are collectively referred to as ΔE (ST).

In the present invention, the excitation singlet energy level E (S, Sh) obtained from the shoulder on the short wavelength side of the fluorescence spectrum, and the excitation singlet energy level E (S) obtained from the peak top on the short wavelength side of the fluorescence spectrum. , PT), the excited triplet energy level E (T, Sh) determined from the shoulder on the short wavelength side of the phosphorescence spectrum, and the excited triplet energy level E (T) determined from the peak top on the short wavelength side of the phosphorescence spectrum. , PT), the inverse intersystem crossing speed, and the light emission speed are calculated as follows.
Here, "the shoulder on the peak short wavelength side" means an inflection point on the short wavelength side of the emission peak, and "the peak top on the short wavelength side" is the emission maximum value of the emission peak, It means the position on the peak corresponding to the emission maximum value on the shortest wavelength side.
When the target compound is a host compound or an assisting dopant as a measurement sample for measuring each energy level, a single film (Neat film, thickness: 50 nm) of the target compound formed on a glass substrate When the target compound is an emitting dopant, a polymethyl methacrylate film (thickness:
10 μm, the concentration of the target compound: 1% by mass). The thickness of the polymethyl methacrylate film in which the target compound is dispersed may be any thickness that can provide sufficient intensity for the measurement of the absorption spectrum, the fluorescence spectrum, and the phosphorescence spectrum. If it is strong, it may be thick. For the excitation light, the wavelength of the absorption peak obtained in the absorption spectrum is used. Of the emission peaks appearing in the fluorescence spectrum or the phosphorescence spectrum, blue emission is in the range of 400 to 500 nm, and green emission is Is determined in the range of 480 to 600 nm, and in the case of red, the respective energy levels are obtained using data obtained from the emission peaks appearing in the range of 580 to 700 nm. When the absorption peak and the emission peak are close to each other and the excitation light is mixed in the emission peak, an absorption peak or absorption shoulder on a shorter wavelength side may be used.
[1] Excited singlet energy level E (S, Sh) obtained from the shoulder on the peak short wavelength side of the fluorescence spectrum
The measurement sample containing the target compound is irradiated with excitation light at 77 K, and the fluorescence spectrum is observed. A tangent line passing through the inflection point (shoulder) on the shorter wavelength side is drawn to the emission peak appearing in the fluorescence spectrum, and the following equation is obtained from the wavelength (B _Sh ) [nm] at the intersection of the tangent line and the baseline. Is used to calculate the excited singlet energy level E (S, Sh).
E (S, Sh) [eV] = 1240 / B _Sh
[2] Excited singlet energy level E (S, PT) obtained from the peak top on the short wavelength side of the fluorescence spectrum
The measurement sample containing the target compound is irradiated with excitation light at 77 K, and the fluorescence spectrum is observed. From the wavelength (emission maximum wavelength, B _PT ) [nm] corresponding to the peak top on the shortest wavelength side of the emission peak appearing in the fluorescence spectrum, the excited singlet energy level E (S, PT) is obtained using the following equation. Is calculated.
E (S, PT) [eV] = 1240 / B _PT
[3] Excited triplet energy level E (T, Sh) obtained from the shoulder on the peak short wavelength side of the phosphorescence spectrum
The measurement sample containing the target compound is irradiated with excitation light at 77 K, and the phosphorescence spectrum is observed. A tangent line passing through the inflection point (shoulder) on the shorter wavelength side is drawn with respect to the emission peak appearing in the phosphorescence spectrum, and from the wavelength (C _Sh ) [nm] at the intersection of the tangent line and the base line, the following equation is obtained. Is used to calculate the excited triplet energy level E (T, Sh).
E (T, Sh) [eV] = 1240 / C _Sh
[4] Excited triplet energy level E (T, PT) obtained from the peak top on the short wavelength side of the phosphorescence spectrum
The measurement sample containing the target compound is irradiated with excitation light at 77 K, and the phosphorescence spectrum is observed. From the wavelength (maximum emission wavelength, C _PT ) [nm] corresponding to the peak top on the shortest wavelength side of the emission peak appearing in the phosphorescence spectrum, the excited triplet energy level E (T, PT) is calculated using the following equation. Is calculated.
E (T, PT) [eV] = 1240 / C _PT

Here, the DA (donor-acceptor) type TADF material and the MRE (Multi Resonance Effect, multiple resonance) type compound have different emission widths of the fluorescence and phosphorescence spectra due to the robustness of the molecule. Even in the same case, it is considered that the DA type thermally activated delayed fluorescent substance has a wider range of energy than the MRE type compound molecule. In the TAF element, it is necessary to accurately estimate the energy transfer between the components and design the configuration. Therefore, the excited singlet energy level and the excited triplet energy level are estimated from the shoulder on the short wavelength side of the spectrum. In general, the intersection of the tangent and the baseline passing through the inflection point on the short wavelength side of the spectrum is the energy determined from the shoulder on the short wavelength side.
The excited singlet energy level E (S, Sh) and the excited triplet energy level E (T, Sh) obtained from the shoulder on the short wavelength side are used for calculation and discussion of ΔE (ST), and the first component It is also used to discuss the confinement and transfer of energy between the host compound and the assisting dopant, and the confinement and transfer of energy between the assisting dopant and the emitting dopant.

[5] Reverse intersystem crossing speed The inverse intersystem crossing speed indicates the speed of the inverse intersystem crossing from the excited triplet to the excited singlet. The inverse intersystem crossing rate of the assisting dopant and the emitting dopant is calculated by transient fluorescence spectrometry using the method described in Nat. Commun. 2015, 6, 8476. or Organic Electronics 2013, 14, 2721-2726. Specifically, the assisting dopant has an inverse intersystem crossing speed of 10 ⁵ s ⁻¹ , and more preferably 10 ⁶ s ⁻¹ .

[6] Light Emission Rate The light emission rate indicates a rate at which a transition from an excited singlet to a ground state occurs via fluorescence emission without going through a TADF process. The emission velocities of the assisting dopant and the emitting dopant are calculated using the method described in Nat. Commun. 2015, 6, 8476. Specifically, the inverse intersystem crossing speed of the emitting dopant is 10 ⁷ s ⁻¹ , and more preferably 10 ⁸ s ⁻¹ .

2. Organic Electroluminescent Element Hereinafter, each layer constituting the organic electroluminescent element of the present invention will be described.
2-1. The light emitting layer in the organic electroluminescent device includes at least a host compound as a first component, a thermally activated delayed phosphor as a second component, and a compound having a boron atom as a third component.
In the present specification, the thermally activated delayed fluorescent substance as the second component is referred to as “assisting dopant” (compound), and the compound having a boron atom as the third component is referred to as “emitting dopant” (compound). There is that.
The light emitting layer may be a single layer or a plurality of layers. Further, the host compound, the thermally activated delayed fluorescent substance, and the compound having a boron atom may be contained in the same layer, or at least one component may be contained in a plurality of layers. The host compound, the thermally activated delayed fluorescent substance, and the compound having a boron atom contained in the light emitting layer may be of one type or a combination of a plurality of types. The assisting dopant and the emitting dopant may be entirely or partially contained in the host compound as the matrix. The emitting layer doped with the assisting dopant and the emitting dopant is formed by depositing the host compound, the assisting dopant, and the emitting dopant by a ternary co-evaporation method, and the host compound, the assisting dopant, and the emitting dopant are mixed in advance. And then simultaneously vapor deposition, applying a composition (paint) for forming a light-emitting layer prepared by dissolving a host compound, an assisting dopant and an emitting dopant in an organic solvent, or a wet film-forming method. it can.

使用 The amount of the host compound used depends on the type of the host compound, and may be determined according to the characteristics of the host compound. The standard of the amount of the host compound used is preferably 40 to 99.999% by mass, more preferably 50 to 99.99% by mass, and still more preferably 60 to 99.9% by mass of the whole material for the light emitting layer. It is. The above range is preferable, for example, in terms of efficient charge transport and efficient energy transfer to the dopant.

(4) The amount of the assisting dopant (thermally activated delayed fluorescent material) used varies depending on the kind of the assisting dopant, and may be determined according to the characteristics of the assisting dopant. The standard of the amount of the assisting dopant to be used is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, further preferably 5 to 30% by mass of the whole material for the light emitting layer. The above range is preferable, for example, in that energy can be efficiently transferred to the emitting dopant.

使用 The amount of the emitting dopant (compound having a boron atom) used depends on the type of the emitting dopant, and may be determined according to the characteristics of the emitting dopant. The standard of the usage amount of the emitting dopant is preferably 0.001 to 30% by mass, more preferably 0.01 to 20% by mass, and still more preferably 0.1 to 10% by mass of the whole material for the light emitting layer. %. The above range is preferable, for example, in that the density quenching phenomenon can be prevented.

(4) It is preferable that the amount of the emitting dopant used is low, since the concentration quenching phenomenon can be prevented. It is preferable that the amount of the assisting dopant used is high from the viewpoint of the efficiency of the thermally activated delayed fluorescence mechanism. Further, from the viewpoint of the efficiency of the thermally activated delayed fluorescence mechanism of the assisting dopant, it is preferable that the amount of the emitting dopant used is lower than that of the assisting dopant.

2-1-1. As the host compound , known compounds can be used, and examples thereof include a compound having at least one of a carbazole ring and a furan ring. Among them, at least one of a furanyl group and a carbazolyl group, It is preferable to use a compound in which at least one of the above is bonded. Specific examples include mCP and mCBP.

The excited triplet energy level E (1, T, Sh) obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the host compound is determined from the viewpoint of promoting the generation of TADF in the light emitting layer without inhibiting the light emitting layer. It is preferable that the emission dopant or the emission dopant having the highest excitation triplet energy level among the excitation triplet energy levels E (2, T, Sh) and E (3, T, Sh) be higher than the above. Specifically, the excited triplet energy level E (1, T, Sh) of the host compound is 0.01 eV or more as compared with E (2, T, Sh) and E (3, T, Sh). Preferably, it is 0.03 eV or more, more preferably, 0.1 eV or more. Further, a TADF-active compound may be used as the host compound.

As the host compound, for example, a compound represented by any of the following formulas (H1), (H2) and (H3) can be used.

In the above formulas (H1), (H2) and (H3), L ¹ is arylene having 6 to 24 carbon atoms, heteroarylene having 2 to 24 carbon atoms, heteroarylene arylene having 6 to 24 carbon atoms or 6 to 24 carbon atoms. Arylene heteroarylene arylene, preferably an arylene having 6 to 16 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms, particularly preferably an arylene having 6 to 10 carbon atoms, specifically, a benzene ring and a biphenyl ring , A terphenyl ring and a fluorene ring. As the heteroarylene, a heteroarylene having 2 to 24 carbon atoms is preferable, a heteroarylene having 2 to 20 carbon atoms is more preferable, a heteroarylene having 2 to 15 carbon atoms is further preferable, and a heteroarylene having 2 to 10 carbon atoms is particularly preferable. Preferably, specifically, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, oxadiazole ring, thiadiazole ring, triazole ring, tetrazole ring, pyrazole ring, pyridine ring, pyrimidine ring, Pyridazine ring, pyrazine ring, triazine ring, indole ring, isoindole ring, 1H-indazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, 1H-benzotriazole ring, quinoline ring, isoquinoline ring, cinnoline ring, quina Phosphorus ring, quinoxaline ring, phthalazine ring, naphthyridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenoxathiin ring, phenoxazine ring, phenothiazine ring, phenazine ring, indolizine ring, furan ring, benzofuran ring, iso And divalent groups such as a benzofuran ring, a dibenzofuran ring, a thiophene ring, a benzothiophene ring, a dibenzothiophene ring, a furazane ring, an oxadiazole ring, and a thianthrene ring.
At least one hydrogen in the compounds represented by each of the above formulas may be substituted with alkyl having 1 to 6 carbon atoms, cyano, halogen or deuterium.

The host compound is preferably a compound represented by any of the structural formulas listed below. In the structural formulas listed below, at least one hydrogen may be substituted with halogen, cyano, alkyl having 1 to 4 carbons (eg, methyl or t-butyl), phenyl or naphthyl.

2-1-2. Thermally activated delayed phosphor (assisting dopant)
The heat-activated delayed fluorescent substance (TADF compound) used in the present invention is capable of forming a HOMO (Highest Occupied Molecular Orbital) in a molecule by using an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor. Donor-acceptor type heat-activated delayed phosphor (DA type) designed to localize LUMO (Lowest Unoccupied Molecular Orbital) and to cause efficient reverse intersystem crossing (TADF compound).
As used herein, the term “electron-donating substituent” (donor) refers to a substituent and a partial structure in which a LUMO orbital is localized in a thermally activated delayed fluorescent molecule. The term “electron-accepting substituent” (acceptor) means a substituent and a partial structure in which a HOMO orbital is localized in a thermally activated delayed fluorescent molecule.
In general, a thermally activated delayed phosphor using a donor or an acceptor has a large spin orbit coupling (SOC) due to its structure, and has a small exchange interaction between HOMO and LUMO and ΔE ( Since ST) is small, a very fast inverse intersystem crossing speed is obtained. On the other hand, thermally activated delayed phosphors using donors and acceptors have a large degree of structural relaxation in the excited state. (Some molecules have different stable structures between the ground state and the excited state. When the conversion to the excited state occurs, the structure changes to a stable structure in the excited state), so that a broad emission spectrum is provided. Therefore, when used as a light-emitting material, color purity may be reduced.

熱 As the heat-activated delayed fluorescent substance of the present invention, for example, a compound in which a donor and an acceptor are bound directly or via a spacer can be used. As the structure of the donor and acceptor used in the heat-activated delayed fluorescent substance of the present invention, for example, the structure described in Chemistry of Materials, 2017, 29, 1946-1963 can be used. Examples of the donor structure include carbazole, dimethylcarbazole, di-tert-butylcarbazole, dimethoxycarbazole, tetramethylcarbazole, benzofluorocarbazole, benzothienocarbazole, phenyldihydroindolocarbazole, phenylbicarbazole, bicarbazole, and tercarbazole. , Diphenylcarbazolylamine, tetraphenylcarbazolyldiamine, phenoxazine, dihydrophenazine, phenothiazine, dimethyldihydroacridine, diphenylamine, bis (tert-butyl) phenyl) amine, (diphenylamino) phenyl) diphenylbenzenediamine, dimethyltetraphenyl Dihydroacridinediamine, tetramethyl-dihydro-indenoacridine and diphenyl Such dihydrodibenz aza cylinder and the like. Acceptable structures include sulfonyldibenzene, benzophenone, phenylenebis (phenylmethanone), benzonitrile, isonicotinonitrile, phthalonitrile, isophthalonitrile, paraphthalonitrile, benzenetricarbonitrile, triazole, oxazole, thiadiazole , Benzothiazole, benzobis (thiazole), benzoxazole, benzobis (oxazole), quinoline, benzimidazole, dibenzoquinoxaline, heptaazaphenalene, thioxanthone dioxide, dimethylanthracenone, anthracenedione, cycloheptapyridine, fluorangecarbonitrile, Triephenyltriazine, pyrazinedicarbonitrile, pyrimidine, phenylpyrimidine, methylpyrimidine, pyridi Dicarbonitrile, dibenzo quinoxaline-carbonitrile, bis (phenylsulfonyl) benzene, dimethyl thio xanthene geo Kido, thian threne tetraoxide and tris (dimethylphenyl) borane is. In particular, the compound having heat-activated delayed fluorescence of the present invention, as a partial structure, carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenylsulfone, triazole And a compound having at least one selected from oxadiazole, thiadiazole and benzophenone.

The compound used as the second component of the light emitting layer of the present invention is a heat-activated delayed fluorescent substance, and is preferably a compound whose emission spectrum at least partially overlaps the absorption peak of the emitting dopant. Hereinafter, compounds that can be used as the second component (heat-activated delayed fluorescent substance) of the light emitting layer of the present invention will be exemplified. However, the compounds that can be used as the heat-activated delayed fluorescent substance in the present invention are not limited to the following exemplified compounds. In the following formula, Me represents methyl, t-Bu represents t-butyl, Ph represents phenyl, and wavy lines represent bonding positions.

Further, a compound represented by any of the following formulas (AD1), (AD2) and (AD3) can also be used as the heat-activated delayed phosphor.

In the above formulas (AD1), (AD2) and (AD3),
M is each independently a single bond, —O—,> N—Ar or> CAr ₂ , and represents the HOMO depth and the excited singlet energy level and the excited triplet energy level of the partial structure to be formed. From the viewpoint of height, a single bond, —O— or> N—Ar is preferable. J is a spacer structure that separates a donor partial structure and an acceptor partial structure, each independently being an arylene having 6 to 18 carbon atoms, and a conjugate leaching from the donor partial structure and the acceptor partial structure. From the viewpoint of the size, arylene having 6 to 12 carbon atoms is preferable. More specifically, phenylene, methylphenylene and dimethylphenylene are mentioned. Q is each independently = C (-H)-or = N-, and the viewpoint of the depth of the LUMO of the partial structure to be formed and the height of the excited singlet energy level and the excited triplet energy level Therefore, it is preferably = N-. Ar is each independently hydrogen, aryl having 6 to 24 carbons, heteroaryl having 2 to 24 carbons, alkyl having 1 to 12 carbons or cycloalkyl having 3 to 18 carbons, and the partial structure to be formed From the viewpoint of the depth of the HOMO and the height of the excited singlet energy level and the excited triplet energy level of the HOMO, preferably hydrogen, aryl having 6 to 12 carbons, heteroaryl having 2 to 14 carbons, carbon number Alkyl of 1-4 or cycloalkyl of 6-10, more preferably hydrogen, phenyl, tolyl, xylyl, mesityl, biphenyl, pyridyl, bipyridyl, triazyl, carbazolyl, dimethylcarbazolyl, di-tert-butyl Carbazolyl, benzimidazole or phenylbenzimidazole, more preferably hydrogen Phenyl or carbazolyl. m is 1 or 2. n is an integer of-(6-m), and preferably an integer of 4- (6-m) from the viewpoint of steric hindrance. Further, at least one hydrogen in the compound represented by each of the above formulas may be substituted with halogen or deuterium.

More specifically, the compound used as the second component of the light emitting layer of the present invention is 4CzBN, 4CzBN-Ph, 5CzBN, 3Cz2DPhCzBN, 4CzIPN, 2PXZ-TAZ, Cz-TRZ3, BDPCC-TPTA, MA-TA, PA -TA, FA-TA, PXZ-TRZ, DMAC-TRZ, BCzT, DCzTrz, DDCzTRz, spiroAC-TRZ, Ac-HPM, Ac-PPM, Ac-MPM, TCzTrz, TmCzTrz and DCzmCzTrz are preferred.

The compound used as the second component of the light emitting layer of the present invention may be a donor-acceptor type TADF compound represented by DA in which one donor D and one acceptor A are bonded directly or via a linking group. It is preferable that the organic electroluminescent device has a structure represented by the following formula (DAD1) in which a plurality of donors D are bonded to one acceptor A through a direct bond or a linking group. It is preferable because it becomes more excellent.
(D ¹ -L ¹ ) nA ¹ (DAD1)
Formula (DAD1) includes a compound represented by the following formula (DAD2).
D ² -L ² -A ² -L ³ -D ³ (DAD2)
In Formula (DAD1) and Formula (DAD2), D ¹ , D ^2, and D ³ each independently represent a donor group. As the donor group, the above donor structure can be employed. A ¹ and A ² each independently represent an acceptor group. As the acceptor group, the above-described acceptor structure can be employed. L ¹ , L ² and L ³ each independently represent a single bond or a conjugated linking group. The conjugated linking group has a spacer structure for separating the donor group and the acceptor group, and is preferably an arylene having 6 to 18 carbon atoms, more preferably an arylene having 6 to 12 carbon atoms. L ¹ , L ² and L ³ are more preferably each independently phenylene, methylphenylene or dimethylphenylene. And n is a 2 or more in the formula (DAD1), represents an integer less than or equal to the maximum number ^{of A 1} may be substituted. n may be selected, for example, in the range of 2 to 10, or in the range of 2 to 6. When n is 2, the compound represented by the formula (DAD2) is obtained. n number of D ¹ may be different even in the same, the n L ¹ may be different even in the same. Preferred specific examples of the compounds represented by the formulas (DAD1) and (DAD2) include 2PXZ-TAZ and the following compounds. Not limited.

2-1-3. Compound containing boron atom (emitting dopant)
The light emitting layer of the organic electroluminescent device of the present invention contains a compound having a boron atom as the third component. The light emitting layer includes, as a compound having a boron atom, a compound represented by any of the following formulas (i), (ii), and (iii), and a multimer having a plurality of structures represented by the following formula (i) Preferably it comprises at least one of the compounds.

The light emitting layer of the organic electroluminescent device of the present invention comprises a compound represented by any of the following formulas (1), (2), (3) and (4) as a third component (compound having a boron atom). More preferably, at least one is included.

For example, as a light emitting material for an organic electroluminescent display, three kinds of materials, a fluorescent material, a phosphorescent material, and a thermally activated delayed fluorescent (TADF) material, are used. About 62.5%. On the other hand, the phosphorescent material and the TADF material sometimes have luminous efficiencies as high as 100%, but both have a problem that the color purity is low (the emission spectrum is wide). The display expresses various colors by mixing the three primary colors of light, red, green and blue, but if the color purity is low, colors that cannot be reproduced will be created, and the image quality of the display will be reduced. It greatly decreases. Therefore, in a commercially available display, unnecessary colors are removed from the emission spectrum by an optical filter to increase the color purity (after narrowing the spectrum width) before use. Therefore, if the original spectrum width is wide, the removal ratio increases, so that even if the luminous efficiency is high, the substantial efficiency is greatly reduced. For example, the half width of the blue emission spectrum of a commercially available smartphone is about 20 to 25 nm, but the half width of a general fluorescent material is about 40 to 60 nm, the phosphorescent material is about 60 to 90 nm, and the TADF material is And about 70 to 100 nm. In the case of using a fluorescent material, it is only necessary to remove some unnecessary colors because the half width is relatively narrow. However, in the case of using a phosphorescent material or a TADF material, it is necessary to remove half or more. From such a background, development of a luminescent material having both luminous efficiency and color purity has been desired.

In general, a TADF material uses an electron-donating substituent called a donor and an electron-accepting substituent called an acceptor to localize HOMO and LUMO in a molecule, so that an efficient reverse intersystem (reverse intersystem) is used. Although crossing is designed to occur, the use of donors and acceptors increases the structural relaxation in the excited state (for some molecules, the stable state is different between the ground state and the excited state, so the ground state is stimulated by external stimuli) When the conversion from the excited state to the excited state occurs, the structure changes to a stable structure in the excited state after that), thereby giving a broad emission spectrum with low color purity.

Therefore, WO 2015/102118 proposes a new molecular design that dramatically improves the color purity of a TADF material. For example, in the compound (1-401) disclosed in the literature, three carbons on a benzene ring composed of six carbons are obtained by utilizing the multiple resonance effect of boron (electron donating) and nitrogen (electron withdrawing). (Black circles) successfully localized HOMO and the remaining three carbons (open circles) localized LUMO. Due to this efficient inverse intersystem crossing, the luminous efficiency of the compound reaches 100% at the maximum. Further, boron and nitrogen of the compound (1-401) not only localize HOMO and LUMO, but also maintain a robust planar structure by condensing three benzene rings, and reduce structural relaxation in an excited state. It also plays a role of suppressing, and as a result, has succeeded in obtaining an emission spectrum with a small Stokes shift of absorption and emission peaks and high color purity. The half width of the emission spectrum is 28 nm, which indicates a level of color purity that surpasses even that of a high-purity fluorescent material that is in practical use. In the dimer compound represented by the formula (1-422), two borons and two nitrogens are bonded to the central benzene ring, thereby further enhancing the multiple resonance effect in the central benzene ring. As a result, it is possible to emit light having an extremely narrow emission peak width.

As a result of our intensive studies, we have (i) introduced an element that modulates the multiple resonance effect at an appropriate position, (ii) introduced a substituent at an appropriate position to distort a molecule and reduce planarity, (Iii) By appropriately combining the three approaches of introducing a highly planar structure at an appropriate position, in the compound, adjustment of the emission wavelength and the half width of the emission spectrum, high emission efficiency and small ΔE (ST ) Was realized in the compound (WO2015 / 102118, Japanese Patent Application No. 2016-174209, Japanese Patent Application No. 2017-097142, Japanese Patent Application No. 2017-248014, PCT / JP2018 / 18731, Japanese Patent Application No. 2018-107092, Japanese Patent Application No. 2018-110876). In the device of the present invention, by utilizing the present compound as an emitting dopant, a high energy transfer efficiency from the assisting dopant to the emitting dopant, an appropriate emission wavelength and a half width of the emission spectrum, a high color purity, and a high device Efficiency and small roll-off, and long life are realized.
Compounds represented by any of the above formulas (i), (ii) and (iii), multimeric compounds having a plurality of structures represented by the formula (i), formulas (1), (2), ( The compound represented by any one of 3) and (4) is a compound obtained by further studying these specific compound examples.
The third component may be a normal phosphor or a thermally activated delayed phosphor.
Hereinafter, each formula and its specific example will be described.

2-1-3 (i). Third component: a compound represented by the following formula (i)

In the above formula (i),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y ¹ is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X ¹ and X ² are each independently O, NR,> CR ₂ , S or Se, wherein R of the NR and R of> CR ₂ are an optionally substituted aryl, Is a heteroaryl, an optionally substituted cycloalkyl or an alkyl, and R of the NR is at least one selected from the above-mentioned ring A, ring B and ring C by a linking group or a single bond. May be combined, and
At least one hydrogen in the compound or structure represented by formula (i) may be replaced with cyano, halogen, or deuterium.

The compound represented by the formula (i) as the third component is preferably a compound represented by the following formula (1).

In the above equation (1),
R ¹ to R ¹¹ (hereinafter also referred to as “R ¹ etc.”) each independently represent hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy (hereinafter, the first) Substituents), which may be further substituted with at least one (or more, a second substituent) selected from aryl, heteroaryl, and alkyl, and R ¹ to R ³ , R ⁴ to R ⁷ and adjacent groups among R ⁸ to R ¹¹ may be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring may be an aryl or heteroaryl , Diarylamino, alkyl, cycloalkyl, alkoxy and aryloxy (at least one of the first substituent In may be substituted, which are further aryl, at least one (or more, the second substituent) selected from heteroaryl and alkyl may be substituted with,
X ¹ and X ² are each independently>O,> NR or> CR ₂ , wherein R of> NR and R of> CR ₂ are aryl, heteroaryl, cycloalkyl or alkyl. And these may be substituted with at least one selected from aryl, heteroaryl, cycloalkyl and alkyl;
However, X ¹ and X ² are not simultaneously> CR ₂ ;
And
At least one hydrogen in the compounds and structures represented by formula (1) may be substituted with cyano, halogen or deuterium.

The “aryl” (first substituent) such as R ¹ may be a single ring or a condensed ring obtained by condensing two or more aromatic hydrocarbon rings, and may have two or more aromatic hydrocarbon rings linked to each other. It may be a connected ring. When two or more aromatic hydrocarbon rings are linked, they may be linked linearly or may be linked branched. “Aryl” is, for example, an aryl having 6 to 30 carbon atoms, preferably an aryl having 6 to 20 carbon atoms, more preferably an aryl having 6 to 16 carbon atoms, further preferably an aryl having 6 to 12 carbon atoms. Aryl of the number 6 to 10 is particularly preferred.

Specific examples of aryl include phenyl which is a monocyclic system, biphenylyl which is a bicyclic system, naphthyl which is a condensed bicyclic system, terphenylyl which is a tricyclic system (m-terphenylyl, o-terphenylyl, p-terphenylyl), condensed Examples include tricyclic, acenaphthenyl, fluorenyl, phenalenyl, phenanthrenyl, fused tetracyclic, triphenylenyl, pyrenyl, naphthacenyl, fused pentacyclic perylenyl, pentacenyl, and the like.

“Heteroaryl” (first substituent) such as R ¹ is a condensed ring in which one or more heterocycles and one or more heterocycles or one or more aromatic hydrocarbon rings are condensed even if they are monocyclic. Alternatively, a connecting ring in which two or more heterocycles are connected may be used. When two or more heterocycles are linked, they may be linked linearly or may be linked branched. “Heteroaryl” is, for example, a heteroaryl having 2 to 30 carbon atoms, preferably a heteroaryl having 2 to 25 carbon atoms, more preferably a heteroaryl having 2 to 20 carbon atoms, and a heteroaryl having 2 to 15 carbon atoms. Is more preferable, and heteroaryl having 2 to 10 carbon atoms is particularly preferable. The heteroaryl is, for example, a heterocyclic ring containing 1 to 5 heteroatoms selected from oxygen, sulfur and nitrogen in addition to carbon as ring-constituting atoms.

Specific examples of the heteroaryl include, for example, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, indolyl, isoindolyl, 1H-indazolyl, Benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, naphthyridinyl, prinyl, pteridinyl, carbazolyl, acridinyl, phenoxathinyl, phenoxazinyl, phenoxazinyll Indolizinyl, furanyl, benzofuranyl, a Benzofuranyl, dibenzofuranyl, thiophenyl, benzothiophenyl, dibenzothiophenyl, furazanyl, oxadiazolyl, and the like thianthrenyl.

As the “aryl” in “diarylamino” (first substituent) such as R ¹ and the “aryl” in “aryloxy” (first substituent), the description of aryl described above can be cited.

As the “aryl” in “diarylboryl” (first substituent) such as R ¹ , the above description of aryl can be cited.

“Alkyl” (first substituent) such as R ¹ may be linear or branched, and is, for example, linear alkyl having 1 to 24 carbons or branched alkyl having 3 to 24 carbons. Alkyl having 1 to 18 carbons (branched alkyl having 3 to 18 carbons) is preferable, alkyl having 1 to 12 carbons (branched alkyl having 3 to 12 carbons) is more preferable, and alkyl having 1 to 6 carbons is preferable. (Branched alkyl having 3 to 6 carbons) is more preferable, and alkyl having 1 to 4 carbons (branched alkyl having 3 to 4 carbons) is particularly preferable.

Specific examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methyl Pentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propyl Pentyl, 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-hepta Sill, n- octadecyl, etc. n- eicosyl and the like.

“Cycloalkyl” (first substituent) such as R ¹ includes cycloalkyl consisting of one ring, cycloalkyl consisting of a plurality of rings, cycloalkyl containing a double bond not conjugated in a ring, and branching outside the ring. Any of the included cycloalkyls may be used, for example, cycloalkyl having 3 to 12 carbon atoms. Cycloalkyl having 5 to 10 carbon atoms is preferable, and cycloalkyl having 6 to 10 carbon atoms is more preferable.

Specific examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo [2,2,1] heptyl, bicyclo [2.2.2] octyl, decahydronaphthyl, adamantyl and the like. No.

“Alkoxy” (first substituent) such as R ¹ may be linear or branched. For example, it is a straight-chain alkoxy having 1 to 24 carbon atoms or a branched alkoxy having 3 to 24 carbon atoms. Alkoxy having 1 to 18 carbon atoms (alkoxy having a branched chain having 3 to 18 carbon atoms) is preferable, alkoxy having 1 to 12 carbons (alkoxy having a branched chain having 3 to 12 carbon atoms) is more preferable, and alkoxy having 1 to 6 carbon atoms is preferable. (Alkoxy having a branched chain having 3 to 6 carbon atoms) is more preferred, and alkoxy having 1 to 4 carbons (an alkoxy having a branched chain having 3 to 4 carbon atoms) is particularly preferred.

Specific alkoxy includes methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy, t-butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy and the like.

As the aryl, heteroaryl or alkyl (the above is the second substituent) further substituting R ¹ or the like (the first substituent), the description of the above-mentioned aryl, heteroaryl or alkyl as the first substituent can be cited.

Specifically, the emission wavelength can be adjusted by the steric hindrance, electron-donating property and electron-withdrawing property of the structure of R ¹ or the like (first substituent), and is preferably a group represented by the following formula. And more preferably methyl, t-butyl, bicyclooctyl, cyclohexyl, 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, diphenylboryl, dimesitylboryl, dibenzooxaborinyl, phenyldibenzodiborinyl, carbazolyl, 3,6-dimethylcarba Zolyl, 3,6-di-t-butylcarbazolyl and phenoxy, more preferably methyl, t-butyl, 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 easiness of synthesis, it is preferable that steric hindrance is large for selective synthesis. Specifically, t-butyl, o-tolyl, 2,6-xylyl, 2,4,6-mesityl , 3,6-dimethylcarbazolyl and 3,6-di-t-butylcarbazolyl are preferred.

In the formula, Me represents methyl, tBu represents t-butyl, and the wavy line represents the bonding position.

Adjacent groups among R ¹ to R ³ , R ⁴ to R ⁷ and R ⁸ to R ^{11 in} the formula (1) are bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring. And the ring structure of the polycyclic aromatic compound represented by the formula (1) changes depending on the mutual bonding form of the substituents on the a-ring, b-ring and c-ring. For example, R ³ of a ring and R ⁴ of b ring, R ⁷ of b ring and R ⁸ of c ring, R ¹¹ of c ring and R ^{1 of} a ring do not correspond to “adjacent groups”. , They do not combine. That is, “adjacent groups” means groups that are adjacent on the same ring.

The “aryl ring” or “heteroaryl ring” formed is an unvalent ring of the aryl or heteroaryl as the first substituent described above. However, the carbon number of the formed ring includes the carbon number of the ring before condensation.

Aryl, heteroaryl, diarylamino, alkyl, alkoxy, or aryloxy (the above, the first substituent) which substitutes on the formed aryl ring or heteroaryl ring, and aryl, hetero, which further substitutes the first substituent As the aryl or alkyl (the above is the second substituent), the description of aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy as R ^{1 and the} like (the first substituent) can be cited.

X in the formula (1) is>O,>NR,> CR ₂ ,> S or> Se, and preferably> O and> NR.

> N-R R and> aryl is R of CR _2, heteroaryl or alkyl (more first substituent), also aryl further substituted to the first substituent, heteroaryl or alkyl (more, the the 2 substituents), aryl as above R ¹ etc. (first substituent), a description of the heteroaryl or alkyl can be cited.

The compound represented by the formula (1) is preferably a compound having the following partial structure.

Next, a specific structure will be described. In the following formula, Me represents methyl, tBu and t-Bu represent t-butyl, and Ph represents phenyl.

2-1-3 (ii). Third component: a compound represented by the following formula (ii)

In the above formula (ii),
A ring, B ring, C ring and D ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y is B (boron),
X ¹ , X ² , X ³ and X ⁴ are each independently>O,>NR,> CR ₂ ,> S or> Se, and R of> NR and> CR ₂ R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted cycloalkyl or an optionally substituted alkyl, and R of the formula> NR represents a linking group. Or may be bonded to at least one selected from the A ring, B ring, C ring and D ring by a single bond,
R ¹ and R ² each independently represent hydrogen, alkyl having 1 to 6 carbons, cycloalkyl having 3 to 12 carbons, aryl having 6 to 12 carbons, heteroaryl or diarylamino having 2 to 15 carbons (Wherein aryl is aryl having 6 to 12 carbon atoms)
At least one hydrogen in the compound represented by the formula (ii) may be substituted with cyano, halogen, or deuterium.

The compound represented by the formula (ii) as the third component is preferably a compound represented by the following formula (2).

In the above equation (2),
R ¹ to R ¹⁴ (hereinafter also referred to as “R ¹ etc.”) each independently represent hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl , alkoxy, aryloxy, heteroaryloxy, arylthio, a heteroarylthio or alkyl-substituted silyl, at least one hydrogen in these, aryl may be substituted with a heteroaryl or alkyl, also, R 5 ^~ R ⁷ and the adjacent groups among R ¹⁰ to R ¹² may be bonded to each other to form an aryl ring or a heteroaryl ring together with the b-ring or the d-ring, and at least one hydrogen in the formed ring is aryl , Heteroaryl, diarylamino, dihe Loarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio or alkyl-substituted silyl, wherein at least one hydrogen is aryl, Optionally substituted with heteroaryl or alkyl,
Y is B (boron),
X ¹ , X ² , X ³ and X ⁴ are each independently>O,> NR or> CR ₂ , wherein R of> NR and R of> CR ₂ have 6 carbon atoms. And aryls having up to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, cycloalkyl having 3 to 12 carbon atoms or alkyl having 1 to 6 carbon atoms, and R of> NR and R of> CR ₂ are —O—, —S—, —C (—R) ₂ — or a single bond may be bonded to at least one selected from the a ring, b ring, c ring and d ring; R of —R) ₂ — is hydrogen or alkyl having 1 to 6 carbons;
However, X ¹ , X ² , X ³ , and X ⁴ are not simultaneously> CR ₂ ;
And
At least one hydrogen in the compounds and structures represented by formula (2) may be substituted with cyano, halogen, or deuterium. )

In the above formula (2), aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy (or more, the first substituent), and aryl, heteroaryl or alkyl (or more, further substituting the first substituent) the second substituent), aryl as above R ¹ etc. (first substituent), heteroaryl, diarylamino, alkyl, a description of the alkoxy or aryloxy can be cited.

The compound represented by the above formula (2) is preferably a compound containing the following partial structure.

The specific structure of the compound represented by the above formula (2) is shown below. In the following formula, Me represents methyl, tBu represents t-butyl, and Ph represents phenyl.

R in the above structure is any of the following groups.

2-1-3 (iii). Third component: a compound represented by the following formula (iii)

In the above formula (iii),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y ¹ is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X ¹ , X ² and X ³ are each independently O, NR,> CR ₂ , S or Se, and R of NR and R of> CR ₂ may be substituted Aryl, optionally substituted heteroaryl, optionally substituted cycloalkyl or alkyl, and R of the NR is selected from the A ring, B ring and C ring by a linking group or a single bond. And may be associated with at least one of
At least one hydrogen in the compound or structure represented by formula (iii) may be substituted with cyano, halogen, or deuterium.

The compound represented by the formula (iii) is preferably a compound represented by the following formula (3).

In the above equation (3),
R ¹ to R ¹¹ (hereinafter also referred to as “R ¹ etc.”) are each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy, Further, it may be substituted with at least one selected from aryl, heteroaryl and alkyl, and adjacent groups among R ¹ to R ³ , R ⁴ to R ⁶ and R ⁹ to R ¹¹ are bonded to each other To form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring is selected from aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy and aryloxy. May be further substituted with at least one aryl, heteroaryl, Le, may be substituted with at least one selected from cycloalkyl and alkyl,
X ¹ , X ² and X ³ are each independently>O,> NR, or> CR ₂ , wherein R of> NR and R of> CR ₂ are aryl, heteroaryl, cycloaryl Alkyl or alkyl, which may be substituted with at least one selected from aryl, heteroaryl and alkyl;
However, X ¹ , X ² , and X ³ are not simultaneously> CR ₂ .
And
At least one hydrogen in the compounds and structures represented by formula (3) may be substituted with cyano, halogen or deuterium.

In the above formula (3), aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy (or more, a first substituent), or aryl, heteroaryl or alkyl (or more, which further substitutes the first substituent) the second substituent), aryl as above R ¹ etc. (first substituent), heteroaryl, diarylamino, alkyl, a description of the alkoxy or aryloxy can be cited.

The specific structure of the above formula (3) is shown below.

2-1-3 (iv). Third component: Compound represented by the following formula (4) The compound represented by the above formula (i) is also preferably a compound represented by the following formula (4).

In the above equation (4),
R ¹ to R ¹⁴ (hereinafter also referred to as “R ¹ etc.”) are each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy; Further, it may be substituted with at least one selected from aryl, heteroaryl and alkyl, and further, among R ¹ to R ³ , R ⁴ to R ⁷ , R ⁸ to R ¹⁰ and R ¹¹ to R ¹⁴ Adjacent groups may combine with each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring, c ring or d ring, and the formed ring is aryl, heteroaryl, diarylamino, alkyl, cyclo May be substituted with at least one selected from alkyl, alkoxy and aryloxy; Further substituted with at least one selected from aryl, heteroaryl and alkyl;
X is>O,> NR or> CR ₂ , wherein R of the above> NR is aryl, heteroaryl or alkyl, which is at least one selected from aryl, heteroaryl and alkyl. May be substituted,
L is a single bond,> CR ₂ ,>O,> S or> NR, and R in the above> CR ₂ and> NR is each independently hydrogen, aryl, heteroaryl, diarylamino , Alkyl, alkoxy or aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl;
However, X and L are simultaneously> not be a CR _2,
And
At least one hydrogen in the compounds and structures represented by formula (4) may be substituted with cyano, halogen or deuterium.

In the above formula (4), aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy (or more, the first substituent), and aryl, heteroaryl or alkyl (or more, further substituting the first substituent) the second substituent), aryl as above R ¹ etc. (first substituent), heteroaryl, diarylamino, alkyl, a description of the alkoxy or aryloxy can be cited.

L in the formula (4) is a single bond,> CR ₂ ,>O,> S or> NR, preferably a single bond,> O or> NR, and more preferably a single bond.

Aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy (hereinafter, the first substituent) which is R of> CR ₂ and> NR, and aryl and heteroaryl further substituting the first substituent or alkyl (more second substituent) as may cite aryl as above R ¹ etc. (first substituent), heteroaryl, diarylamino, alkyl, a description of the alkoxy or aryloxy.

The compound represented by the formula (4) is preferably a compound having the following partial structure.

The specific structure of the compound represented by the above formula (4) is shown below. In the following formula, Me represents methyl and t-Bu represents t-butyl.

The third component of the present invention is at least one of the compounds represented by formulas (i) to (iii), and more specifically, at least one of the compounds represented by formulas (1) to (4). It is preferably one. From the viewpoint of high PLQY, the compounds represented by the formulas (i) and (ii) are preferable, and the compound represented by the formula (ii) is more preferable. More specifically, it is preferable that the planarity of the conjugated structure containing a boron atom is higher, the formulas (1), (2) and (4) are preferable, and the formulas (2) and (4) are more preferable. From the viewpoint of small ΔE (ST), the compounds represented by the formulas (i) and (ii) are preferable, and the compound represented by the formula (ii) is more preferable. More specifically, it is preferable that X, X ¹ , X ² , X ³ and X ⁴ are nitrogen, and formulas (1), (2) and (4) are preferable, and formulas (1) and (4) More preferred. From the viewpoint of a large SOC, the formulas (i) and (ii) are preferable. More specifically, it is better that the conjugated structure containing a boron atom is not a perfect plane but is distorted. Formulas (1), (2) and (4) are preferable, and formulas (1) and (4) are more preferable. , Formula (1) is more preferable.

2-1-3 (v). Third Component: Preferred Substituent In the compounds represented by formulas (i) to (iii) and formulas (1) to (4) which can be used as the third component, the substituent is bonded to the ring present in the compound. It may be an unsubstituted compound which is not substituted, but it is preferable to use a compound substituted with an appropriate substituent. By using a compound substituted with an appropriate substituent as the third component, the characteristics of the organic electroluminescent device are more excellent than when using an unsubstituted compound. Preferred substituents include aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl. More preferred substituents include aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy and aryloxy; more preferred substituents include aryl, diarylamino, alkyl Even more preferred substituents are diarylamino and alkyl; particularly preferred substituents are diarylamino. As used herein, aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl are May be substituted with at least one selected from aryl, heteroaryl, cycloalkyl and alkyl.

The two aryls in the diarylamino may be the same or different, but are preferably the same. Examples of the aryl include phenyl which is a monocyclic system, biphenylyl which is a bicyclic system, naphthyl which is a condensed bicyclic system, terphenylyl which is a tricyclic system (m-terphenylyl, o-terphenylyl, p-terphenylyl), condensed tricyclic system Acenaphthylenyl, fluorenyl, phenalenyl, phenanthrenyl, condensed tetracyclic triphenylenyl, pyrenyl, naphthacenyl, condensed pentacyclic perylenyl, pentacenyl and the like. When the aryl of the diarylamino is substituted, it is preferably substituted with at least one selected from aryl and alkyl. Further, a group in which two aryl groups constituting diarylamino are not bonded to each other may be particularly selected and used. For example, diphenylamino, di (4-methylphenyl) amino, di (4-t-butylphenyl) amino and the like can be mentioned.

Specific examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, 1-methyl Pentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propyl Pentyl, 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-hepta Sill, n- octadecyl, such as n- eicosyl, and the like.

By using a compound having a preferred substituent as the third component, it is possible to improve the external quantum yield of the organic electroluminescent device, to reduce the half width, and to increase the lifetime of the device. Can be Further, by substituting with an appropriate substituent, the lifetime Tau (Delay) of the delayed fluorescence can be shortened, and the Stokes shift can be reduced, thereby improving the performance of the organic electroluminescent device. .
The following particularly preferred energy structures can be constructed and adopted for the second component and the third component by employing a technique such as appropriately selecting a substituent.
E (3, T, Sh) ≧ E (2, T, Sh)
ΔE (2, ST, Sh) ≧ ΔE (3, ST, Sh)
The Stokes shift of the third component is 10 nm or less. The following energy structure is also preferable.
E (3, T, Sh) ≦ E (2, T, Sh)
ΔE (2, ST, Sh) ≦ ΔE (3, ST, Sh)
The Stokes shift of the third component is 15 nm or less. Further, the following energy structure is also preferable.
E (3, T, Sh) ≦ E (2, T, Sh)
ΔE (2, ST, Sh) ≧ ΔE (3, ST, Sh)
The Stokes shift of the third component is larger than 15 nm. In any of the above energy structures, it is preferable that E (3, S, PT) ≧ E (2, S, PT).

2-1-4. Polymer Compound The first component contained in the light emitting layer of the organic electroluminescent device of the present invention may be a polymer compound containing, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from a host compound. The second component contained in the light emitting layer of the organic electroluminescent device of the present invention may be a polymer compound containing, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance. The third component contained in the light emitting layer of the organic electroluminescent device of the present invention may be a polymer compound containing, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from a compound having a boron atom. The two hydrogen atoms to be eliminated can be any two atoms in the compound. It may or may not be two hydrogen atoms bonded to the same ring structure.

The polymer compound contained in the light-emitting layer contains, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from the host compound, and also contains, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance. It may be a polymer compound. The polymer compound contained in the light-emitting layer contains, as a repeating unit, a structure in which two hydrogen atoms are eliminated from a host compound and a structure in which two hydrogen atoms are eliminated from a compound containing a boron atom as a repeating unit. It may be a molecular compound. The polymer compound contained in the light emitting layer contains, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance, and a structure in which two hydrogen atoms have been eliminated from a compound containing a boron atom. It may be a polymer compound containing as a unit. Further, the polymer compound contained in the light emitting layer contains, as a repeating unit, a structure in which two hydrogen atoms have been eliminated from the host compound, and a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance. And a polymer compound containing, as a repeating unit, a structure in which two hydrogen atoms are eliminated from a compound containing a boron atom.

繰り返し The polymer compound contained in the light emitting layer may contain two or more kinds of repeating units having a structure in which two hydrogen atoms are eliminated from the host compound. The polymer compound contained in the light emitting layer may contain two or more kinds of repeating units having a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance. Two or more kinds of repeating units having a structure in which two hydrogen atoms are eliminated from a compound containing a boron atom, which is contained in the polymer compound contained in the light emitting layer, may be used.

The polymer compound contained in the light emitting layer includes a repeating unit having a structure in which two hydrogen atoms have been eliminated from the host compound, a repeating unit having a structure in which two hydrogen atoms have been eliminated from the thermally activated delayed fluorescent substance, and boron. In addition to at least one repeating unit selected from a repeating unit having a structure in which two hydrogen atoms are eliminated from a compound containing an atom, the compound may contain one or more kinds of repeating units different from these. As such a repeating unit, a repeating unit including a structure exhibiting a hole transporting property, a repeating unit including a structure exhibiting an electron transporting property, a repeating unit not exhibiting a hole transporting property or an electron transporting property, and the like are appropriately selected and employed. can do. As preferred repeating units, arylene, heteroarylene, a group in which two or more types of arylene are bonded, a group in which two or more types of heteroarylene are bonded, a group in which at least one type of arylene and at least one type of heteroarylene are bonded, at least one ^A group in which at least one kind of arylene and at least one group represented by -N (R ^A )-are bonded, and a group where at least one kind of heteroarylene is bonded to at least one type of -N (R ^A )- And a group in which at least one kind of arylene, at least one kind of heteroarylene, and at least one kind of a group represented by -N (R ^A )-are bonded. The arylene and heteroarylene mentioned herein may be substituted, and examples of the substituent include alkyl having 1 to 30 carbons, aryl having 6 to 22 carbons, and heteroaryl having 5 to 22 ring skeleton constituting atoms. be able to. Examples of ^RA include alkyl having 1 to 30 carbons, aryl having 6 to 22 carbons, and heteroaryl having 5 to 22 ring skeleton-constituting atoms. Specific examples of the repeating unit include the following structures. The hydrogen atoms present in the structures below may be substituted with alkyl having 1 to 30 carbons, aryl having 6 to 22 carbons, heteroaryl having 5 to 22 ring skeleton-constituting atoms, or the like.

モル The molar ratio of each repeating unit constituting the polymer compound contained in the light emitting layer is not particularly limited. A repeating unit having a structure in which two hydrogen atoms are eliminated from a host compound, a repeating unit having a structure in which two hydrogen atoms are eliminated from a thermally activated delayed fluorescent substance, and two hydrogen atoms are eliminated from a compound containing a boron atom When there are repeating units having an isolated structure, each repeating unit can be selected within the range of 0.01 to 100 mol%. When a repeating unit other than these repeating units is present, the molar ratio of the repeating unit can be selected from the range of 0.01 to 99.99 mol%.

The polymer compound can be synthesized by a known polymerization reaction. For example, it can be synthesized using a known coupling reaction. That is, a first both ends chlorine atom of the repeating unit, a bromine atom, an iodine atom, -O-S (= O) compounds reactive group was coupled such ₂ R ^B constituting the polymer compound, the The desired polymer compound can be easily synthesized by reacting a reactive group at both ends of the first repeating unit with a functional group causing a coupling reaction at both ends of the second repeating unit. can do. Wherein R ^B is alkyl optionally substituted, an optionally substituted cycloalkyl, or also aryl such as optionally substituted. The both ends of the reactive group and a functional group which undergoes a coupling reaction of the first repeat ^{_{_{^{unit, -B (OR C) 2,}}}} BF 3 R D, MgR E, the ^{_{ZnR F, Sn (R G)}} 3 illustrate can do. Here, R ^C and R ^G are a hydrogen atom, an optionally substituted alkyl, an optionally substituted cycloalkyl, or the like, and two or more R ^C or R ^G are connected to each other to form a cyclic structure. You may. ^RD is Li, Na, K, Rb, Cs or the like. ^RE and ^RF are a chlorine atom, a bromine atom or an iodine atom.

The coupling reaction is preferably performed in the presence of a catalyst. As the catalyst, bis (triphenylphosphine) palladium (II) dichloride, bis (tris-o-methoxyphenylphosphine) palladium (II) dichloride, tetrakis (triphenylphosphine) palladium (0), tris (dibenzylideneacetone) dichloride Palladium (0), palladium acetate, tetrakis (triphenylphosphine) nickel (0), [1,3-bis (diphenylphosphino) propane) nickel (II) dichloride, bis (1,4-cyclooctadiene) nickel ( 0), sodium carbonate, potassium carbonate, cesium carbonate, potassium fluoride, cesium fluoride, tripotassium phosphate, tetrabutylammonium fluoride, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, tetrabutylammonium chloride, bromide It can be used tiger butylammonium. By conducting the coupling reaction at -100 to 200 ° C. for about 1 to 24 hours, a desired polymer compound can be synthesized.

(Other organic layers)
The organic electroluminescent device of the present invention may have one or more organic layers in addition to the light emitting layer. Examples of the organic layer include an electron transport layer, a hole transport layer, an electron injection layer, a hole injection layer, and the like, and may further include another organic layer.
FIG. 4 shows an example of a layer configuration of an organic electroluminescent device including these organic layers. 4, reference numeral 101 denotes a substrate, 102 denotes an anode, 103 denotes a hole injection layer, 104 denotes a hole transport layer, 105 denotes a light emitting layer, 106 denotes an electron transport layer, 107 denotes an electron injection layer, and 108 denotes a cathode.
Hereinafter, an organic layer, a cathode and an anode, and a substrate provided in addition to the light emitting layer in the organic electroluminescent device will be described.

2-2. The electron injection layer and the electron transport layer 107 in the organic electroluminescent element play a role of efficiently injecting electrons moving from the cathode 108 into the light emitting layer 105 or the electron transport layer 106. The electron transport layer 106 plays a role in efficiently transporting 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. Each of the electron transport layer 106 and the electron injection layer 107 is formed by laminating and mixing one or more of the electron transport / injection materials.

(4) The electron injection / transport layer is a layer that injects electrons from the cathode and transports the electrons. It is desirable that the electron injection efficiency is high and the injected electrons are transported efficiently. For this purpose, it is preferable that the substance be a substance having a high electron affinity, a high electron mobility, excellent stability, and hardly generating impurities serving as traps during production and use. However, considering the transport balance between holes and electrons, if the role of mainly preventing the holes from the anode from flowing to the cathode side without recombination is to play an important role, the electron transport capability is not so high. Even if it is not high, the effect of improving the luminous efficiency is equivalent to a material having a high electron transporting ability. Therefore, the electron injecting / transporting layer in the present embodiment may include a function of a layer that can efficiently block the movement of holes.

As a material (electron transporting material) for forming the electron transporting layer 106 or the electron injecting layer 107, a compound conventionally used as an electron transporting compound in a photoconductive material, an electron injecting layer and an electron transporting layer of an organic electroluminescent element can be used. Any of the known compounds used can be arbitrarily selected and used.

As the material used for the electron transport layer or the electron injection layer, carbon, hydrogen, oxygen, sulfur, a compound comprising an aromatic ring or a heteroaromatic ring composed of one or more atoms selected from silicon and phosphorus, It is preferable to contain at least one selected from a pyrrole derivative, a fused ring derivative thereof, and a metal complex having an electron-accepting nitrogen. Specifically, condensed ring type aromatic ring derivatives such as naphthalene and anthracene, styryl type aromatic ring derivatives typified by 4,4′-bis (diphenylethenyl) biphenyl, perinone derivatives, coumarin derivatives, naphthalimide derivatives And quinone derivatives such as anthraquinone and diphenoquinone, phosphorus oxide derivatives, carbazole derivatives and indole derivatives. Examples of the metal complex having an electron accepting nitrogen include a hydroxyazole complex such as a hydroxyphenyloxazole complex, an azomethine complex, a tropolone metal complex, a flavonol metal complex, and a benzoquinoline metal complex. These materials may be used alone or in combination with different materials.

Further, specific examples of other electron transfer compounds include pyridine derivatives, naphthalene derivatives, anthracene derivatives, phenanthroline derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, anthraquinone derivatives, diphenoquinone derivatives, diphenylquinone derivatives, perylene derivatives, and oxadiazole. Derivatives (such as 1,3-bis [(4-t-butylphenyl) 1,3,4-oxadiazolyl] phenylene), thiophene derivatives, and triazole derivatives (N-naphthyl-2,5-diphenyl-1,3,4- Triazole), metal complexes of thiadiazole derivatives, oxine derivatives, quinolinol-based metal complexes, quinoxaline derivatives, polymers of quinoxaline derivatives, benzazoles, gallium complexes, pyrazole derivatives, perfluorinated Nylene derivatives, triazine derivatives, pyrazine derivatives, benzoquinoline derivatives (such as 2,2'-bis (benzo [h] quinolin-2-yl) -9,9'-spirobifluorene), imidazopyridine derivatives, borane derivatives, benzones Imidazole derivatives (such as tris (N-phenylbenzimidazol-2-yl) benzene), benzoxazole derivatives, benzothiazole derivatives, quinoline derivatives, oligopyridine derivatives such as terpyridine, bipyridine derivatives, terpyridine derivatives (1,3-bis (4 '-(2,2': 6'2 "-terpyridinyl)) benzene and the like, naphthyridine derivatives (bis (1-naphthyl) -4- (1,8-naphthyridin-2-yl) phenylphosphine oxide and the like), aldazine Derivatives, carbazole derivatives, in Lumpur derivatives, phosphorus oxide derivatives, such as bis-styryl derivatives.

材料 The above-mentioned materials may be used alone, but may be used in combination with different materials.

Among the above-mentioned materials, borane derivatives, pyridine derivatives, fluoranthene derivatives, BO derivatives, anthracene derivatives, benzofluorene derivatives, phosphine oxide derivatives, pyrimidine derivatives, carbazole derivatives, triazine derivatives, benzimidazole derivatives, phenanthroline derivatives, and quinolinol-based metals Complexes are preferred.

2-2-1. Pyridine derivative The pyridine derivative is, for example, a compound represented by the following formula (ETM-2), and preferably a compound represented by the formula (ETM-2-1) or (ETM-2-2).

φ is an n-valent aryl ring (preferably an n-valent benzene ring, naphthalene ring, anthracene ring, fluorene ring, benzofluorene ring, phenalene ring, phenanthrene ring or triphenylene ring), and n is an integer of 1 to 4. is there.

In the above formula (ETM-2-1), R ¹¹ to R ¹⁸ are each independently hydrogen, alkyl (preferably alkyl having 1 to 24 carbon atoms), cycloalkyl (preferably cycloalkyl having 3 to 12 carbon atoms) Alkyl) or aryl (preferably aryl having 6 to 30 carbon atoms).

In the above formula (ETM-2-2), R ¹¹ and R ¹² are each independently hydrogen, alkyl (preferably alkyl having 1 to 24 carbon atoms), cycloalkyl (preferably cycloalkyl having 3 to 12 carbon atoms) Alkyl) or aryl (preferably aryl having 6 to 30 carbon atoms), and R ¹¹ and R ¹² may combine to form a ring.

In each formula, the “pyridine-based substituent” is any of the following formulas (Py-1) to (Py-15), and the pyridine-based substituents are each independently substituted with alkyl having 1 to 4 carbon atoms. It may be. Further, the pyridine-based substituent may be bonded to φ, an anthracene ring or a fluorene ring in each formula via a phenylene group or a naphthylene group.

The pyridine-based substituent is any of the above formulas (Py-1) to (Py-15), and among them, any of the following formulas (Py-21) to (Py-44) Is preferred.

At least one hydrogen in each pyridine derivative may be substituted with deuterium, and among the two “pyridine-based substituents” in the above formula (ETM-2-1) and formula (ETM-2-2) May be replaced by an aryl.

The “alkyl” for R ¹¹ to R ¹⁸ may be linear or branched, and includes, for example, linear alkyl having 1 to 24 carbons or branched alkyl having 3 to 24 carbons. Preferred “alkyl” is alkyl having 1 to 18 carbons (branched alkyl having 3 to 18 carbons). More preferred “alkyl” is alkyl having 1 to 12 carbons (branched alkyl having 3 to 12 carbons). More preferred “alkyl” is alkyl having 1 to 6 carbons (branched alkyl having 3 to 6 carbons). Particularly preferred “alkyl” is alkyl having 1 to 4 carbons (branched alkyl having 3 to 4 carbons).

Specific “alkyl” includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, t-pentyl, n-hexyl, -Methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, t-octyl, 1-methylheptyl, 2-ethylhexyl, -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-he Tadeshiru, n- octadecyl, etc. n- eicosyl and the like.

As the alkyl having 1 to 4 carbon atoms to be substituted with the pyridine-based substituent, the description of the above alkyl can be cited.

“Cycloalkyl” for R ¹¹ to R ¹⁸ includes, for example, cycloalkyl having 3 to 12 carbon atoms. Preferred “cycloalkyl” is cycloalkyl having 3 to 10 carbon atoms. More preferred “cycloalkyl” is cycloalkyl having 3 to 8 carbon atoms. More preferred “cycloalkyl” is cycloalkyl having 3 to 6 carbon atoms.
Specific “cycloalkyl” includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, dimethylcyclohexyl and the like.

The “aryl” in R ¹¹ to R ¹⁸ may be a single ring, a condensed ring in which two or more aromatic hydrocarbon rings are fused, or a connecting ring in which two or more aromatic hydrocarbon rings are linked. There may be. When two or more aromatic hydrocarbon rings are linked, they may be linked linearly or may be linked branched. Preferred aryl is aryl having 6 to 30 carbons, more preferred aryl is aryl having 6 to 18 carbons, still more preferred is aryl having 6 to 14 carbons, and particularly preferred is aryl having 6 to 12 carbons. It is.

Specific examples of the aryl include, for example, phenyl which is a monocyclic aryl, biphenylyl which is a bicyclic aryl (2-biphenylyl, 3-biphenylyl, 4-biphenylyl), and naphthyl (1-naphthyl) which is a fused bicyclic aryl , 2-naphthyl), terphenylyl which is a tricyclic aryl (m-terphenyl-2'-yl, m-terphenyl-4'-yl, m-terphenyl-5'-yl, o-terphenyl-3 '-Yl, o-terphenyl-4'-yl, p-terphenyl-2'-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl , O-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-2-yl, p-terphenyl-3-yl, p-te Phenyl-4-yl), fused tricyclic aryl, acenaphthylenyl (acenaphthylene-1-yl, acenaphthylene-3-yl, acenaphthylene-4-yl, acenaphthylene-5-yl), fluorenyl (fluoren-1-yl, Fluoren-2-yl, fluoren-3-yl, fluoren-4-yl, fluoren-9-yl), phenalenyl (phenalen-1-yl, phenalen-2-yl), phenanthryl (1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl), quaterphenylyl (5'-phenyl-m-terphenyl-2-yl, 5'-phenyl-m-terphenyl-3-) which is a tetracyclic aryl Yl, 5'-phenyl-m-terphenyl-4-yl, m-quaterfe Yl), condensed tetracyclic aryl triphenylene (triphenylen-1-yl, triphenylen-2-yl), pyrenyl (pyren-1-yl, pyren-2-yl, pyren-4-yl), naphthacenyl (naphthacene- 1-yl, naphthacene-2-yl, naphthacene-5-yl), condensed pentacyclic aryl perylenyl (perylene-1-yl, perylene-2-yl, perylene-3-yl), pentacenyl (pentacene-1) -Yl, pentacene-2-yl, pentacene-5-yl, pentacene-6-yl) and the like.

Preferred “aryl having 6 to 30 carbon atoms” include phenyl, naphthyl, phenanthryl, chrysenyl or triphenylenyl, more preferably phenyl, 1-naphthyl, 2-naphthyl or phenanthryl, and particularly preferably phenyl, -Naphthyl or 2-naphthyl.

R ¹¹ and R ¹² in the above formula (ETM-2-2) may combine to form a ring, and as a result, the 5-membered ring of the fluorene skeleton has cyclobutane, cyclopentane, cyclopentene, cyclopentadiene, Cyclohexane, fluorene or indene may be spiro-bonded.

Specific examples of the pyridine derivative include, for example, the following compounds.

ピリジン This pyridine derivative can be produced using a known raw material and a known synthesis method.

2-2-2. Phosphine oxide derivative The phosphine oxide derivative is, for example, a compound represented by the following formula (ETM-7-1). The details are also described in WO2013 / 079217.

R ⁵ is a substituted or unsubstituted alkyl having 1 to 20 carbons, an aryl having 6 to 20 carbons or a heteroaryl having 5 to 20 carbons,
R ⁶ is CN, substituted or unsubstituted alkyl having 1 to 20 carbons, heteroalkyl having 1 to 20 carbons, aryl having 6 to 20 carbons, heteroaryl having 5 to 20 carbons, 1 to carbons 20 alkoxy or aryloxy having 6 to 20 carbon atoms,
R ⁷ and R ⁸ are each independently a substituted or unsubstituted aryl having 6 to 20 carbons or a heteroaryl having 5 to 20 carbons,
R ⁹ is oxygen or sulfur;
j is 0 or 1, k is 0 or 1, r is an integer of 0 to 4, and q is an integer of 1 to 3.

The phosphine oxide derivative may be, for example, a compound represented by the following formula (ETM-7-2).

R ¹ to R ³ may be the same or different, and include hydrogen, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkoxy group, an alkylthio group, an arylether group, and an arylthioether group. , An aryl group, a heterocyclic group, a halogen, a cyano group, an aldehyde group, a carbonyl group, a carboxyl group, an amino group, a nitro group, a silyl group, and a condensed ring formed between adjacent substituents.

Ar ¹ may be the same or different and is an arylene group or a heteroarylene group, and Ar ² may be the same or different and is an aryl group or a heteroaryl group. However, at least one of Ar ¹ and Ar ² has a substituent or forms a condensed ring with an adjacent substituent. n is an integer of 0 to 3. When n is 0, there is no unsaturated structure part, and when n is 3, R ¹ does not exist.

アルキル Of these substituents, the alkyl group means a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, and a butyl group, which may be unsubstituted or substituted. When substituted, the substituent is not particularly limited, and examples thereof include an alkyl group, an aryl group, and a heterocyclic group. This point is also common to the following description. The number of carbon atoms in the alkyl group is not particularly limited, but is usually in the range of 1 to 20 from the viewpoint of availability and cost.

Further, the cycloalkyl group refers to, for example, a saturated alicyclic hydrocarbon group such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl, which may be unsubstituted or substituted. The number of carbon atoms in the alkyl group is not particularly limited, but is usually in the range of 3 to 20.

The aralkyl group refers to, for example, an aromatic hydrocarbon group via an aliphatic hydrocarbon such as a benzyl group and a phenylethyl group, and both the aliphatic hydrocarbon and the aromatic hydrocarbon are unsubstituted or substituted. It doesn't matter. The carbon number of the aliphatic moiety is not particularly limited, but is usually in the range of 1 to 20.

アルケニ Alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, an allyl group and a butadienyl group, which may be unsubstituted or substituted. The number of carbon atoms of the alkenyl group is not particularly limited, but is usually in the range of 2 to 20.

The cycloalkenyl group refers to, for example, an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, and a cyclohexene group, which may be unsubstituted or substituted. I don't care.

アル Alkynyl group means, for example, an unsaturated aliphatic hydrocarbon group containing a triple bond such as an acetylenyl group, which may be unsubstituted or substituted. The number of carbon atoms in the alkynyl group is not particularly limited, but is usually in the range of 2 to 20.

アルコキシ Alkoxy group means, for example, an aliphatic hydrocarbon group via an ether bond such as a methoxy group, and the aliphatic hydrocarbon group may be unsubstituted or substituted. Although the carbon number of the alkoxy group is not particularly limited, it is usually in the range of 1 to 20.

アルキル Alkylthio group is a group in which an oxygen atom of an ether bond of an alkoxy group is substituted with a sulfur atom.

The aryl ether group refers to, for example, an aromatic hydrocarbon group via an ether bond such as a phenoxy group, and the aromatic hydrocarbon group may be unsubstituted or substituted. The number of carbon atoms in the aryl ether group is not particularly limited, but is usually in the range of 6 to 40.

アリール The arylthioether group is a group in which the oxygen atom of the ether bond of the arylether group is substituted with a sulfur atom.

アリール The aryl group refers to, for example, an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenylyl group, a phenanthryl group, a terphenyl group, and a pyrenyl group. The aryl group may be unsubstituted or substituted. The carbon number of the aryl group is not particularly limited, but is usually in the range of 6 to 40.

Further, the heterocyclic group refers to, for example, a cyclic structure group having an atom other than carbon, such as a furanyl group, a thiophenyl group, an oxazolyl group, a pyridyl group, a quinolinyl group, and a carbazolyl group. It doesn't matter. The carbon number of the heterocyclic group is not particularly limited, but is usually in the range of 2 to 30.

Halogen refers to fluorine, chlorine, bromine and iodine.

The aldehyde group, carbonyl group, and amino group may also include groups substituted with an aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, a heterocyclic ring, and the like.

脂肪 Alternatively, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and heterocycles may be unsubstituted or substituted.

The term "silyl group" means a silicon compound group such as a trimethylsilyl group, which may be unsubstituted or substituted. Although the carbon number of the silyl group is not particularly limited, it is usually in the range of 3 to 20. Further, the number of silicon is usually 1 to 6.

The condensed ring formed between adjacent substituents is, for example, Ar ¹ and R ² , Ar ¹ and R ³ , Ar ² and R ² , Ar ² and R ³ , R ² and R ³ , Ar ¹ and It is a conjugated or non-conjugated fused ring formed between Ar ² and the like. Here, when n is 1, may be formed conjugated or non-conjugated fused ring with two of R ¹ each other. These condensed rings may contain nitrogen, oxygen and sulfur atoms in the ring structure, or may be condensed with another ring.

Specific examples of the phosphine oxide derivative include the following compounds.

This phosphine oxide derivative can be produced using a known raw material and a known synthesis method.

2-2-3. Pyrimidine Derivative The pyrimidine derivative is, for example, a compound represented by the following formula (ETM-8), and preferably a compound represented by the following formula (ETM-8-1). The details are also described in WO 2011/021689.

Ar is each independently an optionally substituted aryl or an optionally substituted heteroaryl. n is an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2 or 3.

The “aryl” of the “optionally substituted aryl” may be a single ring, a condensed ring obtained by condensing two or more aromatic hydrocarbon rings, or two or more aromatic hydrocarbon rings linked to each other. It may be a connected ring. When two or more aromatic hydrocarbon rings are linked, they may be linked linearly or may be linked branched. “Aryl” includes, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 24 carbon atoms, more preferably aryl having 6 to 20 carbon atoms, and still more preferably aryl having 6 to 12 carbon atoms. It is.

The “heteroaryl” of the “optionally substituted heteroaryl” may be a single ring or a condensed ring in which one or more heterocycles and one or more heterocycles or one or more aromatic hydrocarbon rings are fused. Alternatively, it may be a connecting ring in which two or more heterocycles are connected. When two or more heterocycles are linked, they may be linked linearly or may be linked branched. “Heteroaryl” includes, for example, heteroaryl having 2 to 30 carbon atoms, preferably heteroaryl having 2 to 25 carbon atoms, more preferably heteroaryl having 2 to 20 carbon atoms, and 2 to 15 carbon atoms. Heteroaryl is more preferred, and heteroaryl having 2 to 10 carbon atoms is particularly preferred. The heteroaryl includes, for example, a heterocyclic ring containing 1 to 5 hetero atoms selected from oxygen, sulfur and nitrogen in addition to carbon as ring-constituting atoms.

Specific examples of the heteroaryl include, for example, furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, oxadiazolyl, furazanil, thiadiazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, triazinyl, benzofuranyl, benzofuranyl, Isobenzofuranyl, benzo [b] thienyl, indolyl, isoindolyl, 1H-indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, 1H-benzotriazolyl, quinolyl, isoquinolyl, cinnolyl, quinazolyl, quinoxalinyl, phthalazinyl, naphthyridinyl, purinyl , Pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, Enajiniru, phenoxathiinyl, thianthrenyl, indolizinyl, and the like.

The above aryl and heteroaryl may be substituted, for example, each of the above aryl and heteroaryl may be substituted.

Specific examples of the pyrimidine derivative include, for example, the following compounds.

This pyrimidine derivative can be produced using a known raw material and a known synthesis method.

2-2-4. Triazine derivative The triazine derivative is, for example, a compound represented by the following formula (ETM-10), and preferably a compound represented by the following formula (ETM-10-1). Details are described in U.S. Publication No. 2011/0156013.

The “aryl” of the “optionally substituted aryl” includes, for example, aryl having 6 to 30 carbon atoms, preferably aryl having 6 to 24 carbon atoms, more preferably aryl having 6 to 20 carbon atoms, More preferably, it is an aryl having 6 to 12 carbon atoms.

Specific examples of the triazine derivative include, for example, the following compounds.

This triazine derivative can be produced using a known raw material and a known synthesis method.

2-2-5. Benzimidazole derivative The benzimidazole derivative is, for example, a compound represented by the following formula (ETM-11).

φ is an n-valent aryl ring (preferably an n-valent benzene ring, naphthalene ring, anthracene ring, fluorene ring, benzofluorene ring, phenalene ring, phenanthrene ring or triphenylene ring), and n is an integer of 1 to 4. The “benzimidazole-based substituent” means that the pyridyl group in the “pyridine-based substituent” in the above formulas (ETM-2), (ETM-2-1) and (ETM-2-2) is benzo. It is a substituent replacing the imidazole group, and at least one hydrogen in the benzimidazole derivative may be substituted with deuterium.

R ¹¹ in the benzimidazole group is hydrogen, alkyl having 1 to 24 carbons, cycloalkyl having 3 to 12 carbons or aryl having 6 to 30 carbons, and is represented by the above formula (ETM-2-1) or ( It may be cited to the description of ^{R 11} in ETM-2-2).

φ is further preferably an anthracene ring or a fluorene ring, and in this case, the structure described in the above formula (ETM-2-1) or (ETM-2-2) can be referred to. In the formulas, R ¹¹ to R ¹⁸ can refer to the description in the above formula (ETM-2-1) or formula (ETM-2-2). In the above formula (ETM-2-1) or (ETM-2-2), two pyridine-based substituents are described as being bonded. However, when these are replaced with benzimidazole-based substituents, both are substituted. May be replaced with a benzimidazole-based substituent (that is, n = 2), or one of the pyridine-based substituents may be replaced with a benzimidazole-based substituent and the other pyridine-based substituent may be substituted with R ¹¹ It may be replaced by ~ ^{R 18} (i.e. n = 1). Further, for example, at least one of R ¹¹ to R ¹⁸ in the above formula (ETM-2-1) may be replaced with a benzimidazole-based substituent, and the “pyridine-based substituent” may be replaced with R ¹¹ to R ¹⁸ .

Specific examples of the benzimidazole derivative include, for example, 1-phenyl-2- (4- (10-phenylanthracen-9-yl) phenyl) -1H-benzo [d] imidazole, 2- (4- (10- ( Naphthalen-2-yl) anthracen-9-yl) phenyl) -1-phenyl-1H-benzo [d] imidazole, 2- (3- (10- (naphthalen-2-yl) anthracen-9-yl) phenyl) -1-phenyl-1H-benzo [d] imidazole, 5- (10- (naphthalen-2-yl) anthracen-9-yl) -1,2-diphenyl-1H-benzo [d] imidazole, 1- (4 -(10- (naphthalen-2-yl) anthracen-9-yl) phenyl) -2-phenyl-1H-benzo [d] imidazole, 2- (4- (9,10 Di (naphthalen-2-yl) anthracen-2-yl) phenyl) -1-phenyl-1H-benzo [d] imidazole, 1- (4- (9,10-di (naphthalen-2-yl) anthracene-2) -Yl) phenyl) -2-phenyl-1H-benzo [d] imidazole, 5- (9,10-di (naphthalen-2-yl) anthracen-2-yl) -1,2-diphenyl-1H-benzo [ d] Imidazole and the like.

This benzimidazole derivative can be produced using a known raw material and a known synthesis method.

2-2-6. Phenanthroline derivative The phenanthroline derivative is, for example, a compound represented by the following formula (ETM-12) or (ETM-12-1). Details are described in WO 2006/021982.

R ¹¹ to R ^{18 in} each formula are each independently hydrogen, alkyl (preferably alkyl having 1 to 24 carbons), cycloalkyl (preferably cycloalkyl having 3 to 12 carbons) or aryl (preferably carbon Aryl of formulas 6 to 30). In the above formula (ETM-12-1), any one of R ¹¹ to R ¹⁸ bonds to φ which is an aryl ring.

少なくとも At least one hydrogen in each phenanthroline derivative may be replaced with deuterium.

Alkyl in R ¹¹ ~ ^{R 18,} cycloalkyl and aryl may be cited to the description of ^R 11 ^{~ R 18} in the formula (ETM-2). Φ is, for example, the following structural formula in addition to the above examples. R in the following structural formulas is each independently hydrogen, methyl, ethyl, isopropyl, cyclohexyl, phenyl, 1-naphthyl, 2-naphthyl, biphenylyl or terphenylyl.

Specific examples of the phenanthroline derivative include, for example, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 9,10-di (1,10- Phenanthroline-2-yl) anthracene, 2,6-di (1,10-phenanthroline-5-yl) pyridine, 1,3,5-tri (1,10-phenanthroline-5-yl) benzene, 9,9 ′ -Difluoro-bis (1,10-phenanthroline-5-yl), bathocuproine, 1,3-bis (2-phenyl-1,10-phenanthroline-9-yl) benzene and the like.

This phenanthroline derivative can be produced using a known raw material and a known synthesis method.

2-2-7. Quinolinol-based metal complex The quinolinol-based metal complex is, for example, a compound represented by the following formula (ETM-13).

In the formula, R ¹ to R ⁶ are hydrogen or a substituent, M is Li, Al, Ga, Be or Zn, and n is an integer of 1 to 3.

Specific examples of quinolinol-based metal complexes include 8-quinolinol lithium, tris (8-quinolinolate) aluminum, tris (4-methyl-8-quinolinolate) aluminum, tris (5-methyl-8-quinolinolate) aluminum, tris (3 , 4-Dimethyl-8-quinolinolate) aluminum, tris (4,5-dimethyl-8-quinolinolate) aluminum, tris (4,6-dimethyl-8-quinolinolate) aluminum, bis (2-methyl-8-quinolinolate) ( Phenolate) aluminum, bis (2-methyl-8-quinolinolate) (2-methylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (3-methylphenolate) aluminum, bis (2-methyl-8- Quinolinolate) (4- Butylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (3-phenylphenolate) aluminum, bis (2-methyl- 8-quinolinolate) (4-phenylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,3-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,6-dimethyl Phenolate) aluminum, bis (2-methyl-8-quinolinolate) (3,4-dimethylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (3,5-dimethylphenolate) aluminum, bis (2 -Methyl-8-quinolinolate) (3,5-di-t- Tyl phenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,6-diphenylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,4,6-triphenylphenolate) aluminum Bis (2-methyl-8-quinolinolate) (2,4,6-trimethylphenolate) aluminum, bis (2-methyl-8-quinolinolate) (2,4,5,6-tetramethylphenolate) aluminum, Bis (2-methyl-8-quinolinolate) (1-naphtholate) aluminum, bis (2-methyl-8-quinolinolate) (2-naphtholate) aluminum, bis (2,4-dimethyl-8-quinolinolate) (2-phenyl Phenolate) aluminum, bis (2,4-dimethyl-8-quinolinoler) G) (3-phenylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolate) (4-phenylphenolate) aluminum, bis (2,4-dimethyl-8-quinolinolate) (3,5-dimethyl Phenolate) aluminum, bis (2,4-dimethyl-8-quinolinolate) (3,5-di-t-butylphenolato) aluminum, bis (2-methyl-8-quinolinolate) aluminum-μ-oxo-bis ( 2-methyl-8-quinolinolate) aluminum, bis (2,4-dimethyl-8-quinolinolate) aluminum-μ-oxo-bis (2,4-dimethyl-8-quinolinolate) aluminum, bis (2-methyl-4- Ethyl-8-quinolinolate) aluminum-μ-oxo-bis (2-methyl-4-ethyl- -Quinolinolate) aluminum, bis (2-methyl-4-methoxy-8-quinolinolate) aluminum-μ-oxo-bis (2-methyl-4-methoxy-8-quinolinolate) aluminum, bis (2-methyl-5-cyano) -8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-cyano-8-quinolinolato) aluminum, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) aluminum-μ-oxo-bis (2-methyl-5-trifluoromethyl-8-quinolinolate) aluminum, bis (10-hydroxybenzo [h] quinoline) beryllium and the like.

This quinolinol-based metal complex can be produced using a known raw material and a known synthesis method.

The electron transport layer or the electron injection layer may further contain a substance capable of reducing a material forming the electron transport layer or the electron injection layer. As the reducing substance, various substances having a certain reducing property are used, for example, alkali metals, alkaline earth metals, rare earth metals, alkali metal oxides, alkali metal halides, alkali metals, and the like. From the group consisting of earth metal oxides, alkaline earth metal halides, rare earth metal oxides, rare earth metal halides, alkali metal organic complexes, alkaline earth metal organic complexes, and rare earth metal organic complexes At least one selected can be suitably used.

Preferred reducing substances include alkali metals such as Na (2.36 eV), K (2.28 eV), Rb (2.16 eV) or Cs (1.95 eV), and Ca (2. eV). Alkaline earth metals such as 9 eV), Sr (2.0 to 2.5 eV) and Ba (2.52 eV), and those having a work function of 2.9 eV or less are particularly preferable. Among these, a more preferable reducing substance is an alkali metal of K, Rb or Cs, further 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 transporting layer or the electron injecting layer can improve the emission luminance and extend the life of the organic electroluminescent device. Further, as a reducing substance having a work function of 2.9 eV or less, a combination of two or more of these alkali metals is also preferable. In particular, a combination containing Cs, for example, Cs and Na, Cs and K, Cs and Rb, or A combination of Cs, Na and K is preferred. By containing Cs, the reduction ability can be efficiently exhibited, and the addition to the material forming the electron transport layer or the electron injection layer can improve the emission luminance and extend the life of the organic electroluminescent device. .

2-3. The cathode in the organic electroluminescent device plays a role of injecting electrons into the light emitting layer 105 via the electron injection layer 107 and the electron transport layer.

材料 The material for forming the cathode 108 is not particularly limited as long as the material can efficiently inject electrons into the organic layer, and the same material as the material for forming the anode 102 can be used. Among them, metals such as tin, indium, calcium, aluminum, silver, copper, nickel, chromium, gold, platinum, iron, zinc, lithium, sodium, potassium, cesium and magnesium or alloys thereof (magnesium-silver alloy, magnesium) -An indium alloy, an aluminum-lithium alloy such as lithium fluoride / aluminum, etc.). In order to increase the electron injection efficiency and improve the device characteristics, lithium, sodium, potassium, cesium, calcium, magnesium or an alloy containing these low work function metals is effective. However, these low work function metals are generally often unstable in the atmosphere. In order to improve this point, for example, a method is known in which an organic layer is doped with a small amount of lithium, cesium, or magnesium to use a highly stable electrode. 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, for electrode protection, 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, and vinyl chloride It is preferable to laminate a hydrocarbon polymer compound and the like. The method for producing these electrodes is not particularly limited as long as conduction can be achieved, such as resistance heating, electron beam evaporation, sputtering, ion plating, and coating.

2-4. The hole injection layer and the hole transport layer 103 in the organic electroluminescent element serve to inject holes moving from the anode 102 into the light emitting layer 105 or the hole transport layer 104 efficiently. To fulfill. The hole transport layer 104 plays a role in efficiently transporting 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 each formed by laminating and mixing one or more of the hole injection / transport materials or a mixture of the hole injection / transport material and the polymer binder. Is done. Further, a layer may be formed by adding an inorganic salt such as iron (III) chloride to the hole injecting / transporting material.

As a hole injection / transport substance, it is necessary to efficiently inject and transport holes from the positive electrode between the electrodes to which an electric field is applied, and the hole injection efficiency is high, and the injected holes are efficiently transported. It is desirable to do. For that purpose, it is preferable that the ionization potential is small, the hole mobility is large, the stability is further improved, and impurities serving as traps are less likely to be generated during production and use.

As a material for forming the hole injection layer 103 and the hole transport layer 104, a compound conventionally used as a hole charge transport material in a photoconductive material, a p-type semiconductor, and a hole injection layer of an organic electroluminescent element are used. Any of the known materials used for the layer and the hole transport layer can be selected and used. Specific examples thereof include a carbazole derivative (N-phenylcarbazole, polyvinylcarbazole, etc.), a biscarbazole derivative such as bis (N-arylcarbazole) or bis (N-alkylcarbazole), and a triarylamine derivative (aromatic tertiary). Polymer having amino in the main chain or side chain, 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-di (3-methylphenyl) -4 , 4'-Diaminobiphenyl, N, N'-diphenyl-N, N'-dinaphthyl-4,4'-diaminobiphenyl, N, N'-diphenyl-N, N'-di (3-methylphenyl) -4 , 4′-Diphenyl-1,1′-diamine, N, N′-dinaphthyl-N, N′-diphenyl-4,4′-diphenyl-1,1′-diamine, ^4, N ^{4 '-} diphenyl ^-N ^4, N ^4' - bis (9-phenyl -9H- carbazol-3-yl) - [1,1'-biphenyl] ^{-4,4'-diamine, N} 4, N ⁴ , N ^{4 ′} , N ^4′ -tetra [1,1′-biphenyl] -4-yl)-[1,1′-biphenyl] -4,4′-diamine, 4,4 ′, 4 ″ -tris (Triphenylamine derivatives such as (3-methylphenyl (phenyl) amino) triphenylamine, starburst amine derivatives, etc.), stilbene derivatives, phthalocyanine derivatives (metal-free, copper phthalocyanine, etc.), pyrazoline derivatives, hydrazone compounds, benzofuran derivatives And thiophene derivatives, oxadiazole derivatives, quinoxaline derivatives (eg, 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7, 0,11-hexacarbonitrile), heterocyclic compounds such as porphyrin derivatives, polysilanes, etc. In the polymer system, polycarbonates having the above monomers in the side chain, styrene derivatives, polyvinyl carbazole, polysilanes and the like are preferable, but light emission is preferred. The compound is not particularly limited as long as it is a compound capable of forming a thin film required for manufacturing an element, injecting holes from the anode, and transporting holes.

It is also known that the conductivity of an organic semiconductor is strongly affected by its doping. Such an organic semiconductor matrix material is composed of a compound having a good electron donating property or a compound having a good electron accepting property. Strong electron acceptors such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluorotetracyano-1,4-benzoquinonedimethane (F4TCNQ) are known for doping of electron donors. (See, for example, M. Pfeiffer, A. Beyer, T. Fritz, K. Leo, Appl. Phys. Lett., 73 (22), 3202-3204 (1998)) and the document J. Blochwitz, M. Pheiffer, 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 transporting material). Depending on the number and mobility of the holes, the conductivity of the base material varies considerably. As a matrix material having a hole transporting property, for example, a benzidine derivative (such as TPD) or a starburst amine derivative (such as TDATA), or a specific metal phthalocyanine (particularly, zinc phthalocyanine ZnPc or the like) is known (Japanese Unexamined Patent Application, First Publication No. H11-163686). 2005-167175).

As a material for forming the hole injection layer 103 and the hole transport layer 104 by using a wet film formation method, a material for forming the hole injection layer 103 and the hole transport layer 104 used for the above-described vapor deposition is used. In addition, a hole-injecting and hole-transporting polymer, a hole-injecting and hole-transporting crosslinkable polymer, a hole-injecting and hole-transporting polymer precursor, and a polymer An initiator or the like can be used. For example, PEDOT: PSS, polyaniline compounds (described in JP-A-2005-108828, WO 2010/058776, WO 2013/042623, etc.), fluorene polymers (JP-A-2011-251984, 2011-501449, JP 2012-533661, etc.), "Xiaohui Yang, David C. Muller, Dieter Neher, Klaus Meerholz, Organic Electronics, 12,2253-2257 (2011)", "Philipp Zacharias, Malte C. Gather, Markus Rojahn, Oskar Nuyken, Klaus Meerholz, Angew. Chem. Int. Ed., 46,4388-4392 (2007), `` Chei-Yen, Yu-Cheng Lin, Wen-Yi Hung, Ken- Tsung Wong, Raymond C. Kwong, Sean C. Xia, Yu-Hung Chen, Chih-I Wu, J. Mater. Chem., 618 19, 3618-3626 (2009), `` Fei Huang, Yen-Ju Cheng, Yong Zhang, Michelle S. Liu, Alex K.-Y. Jen, J. Mater.Chem., 18, 4495-4509 (2008) '' Carlos A. Zuniga, Jassem Abdallah, Wojciech Haske, Yadong Zhang, Igor Coropceanu, Stephen Barlow, Bernard Kippelen, Seth R. Marder, Adv.Mater., 25,1739-1744 (2013), H -Yen Lin, Tsang-Lung Cheng, Shih-Wei Yang, Atul Chaskar, Gang-Lun Fan, Ken-Tsung Wong, Teng-Chih Chao, Mei-Rurng Tseng, Organic Electronics, 13,2508-25ron And the compounds described in the above.

2-5. The anode 102 in the organic electroluminescent device plays a role of injecting holes into the light emitting layer 105. Note that when the hole injection layer 103 and / or the hole transport layer 104 are provided between the anode 102 and the light-emitting layer 105, holes are injected into the light-emitting layer 105 through these layers. .

材料 As a material for forming the anode 102, an inorganic compound and an organic compound can be given. 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), metal halides (eg, copper iodide), copper sulfide, carbon black, ITO glass, Nesa glass, and the like. Examples of the organic compound include conductive polymers such as polythiophene such as poly (3-methylthiophene), polypyrrole, and polyaniline. In addition, it can be appropriately selected from the substances used as the anode of the organic electroluminescent element.

(4) The resistance of the transparent electrode is not limited as long as a current sufficient for light emission of the light emitting element can be supplied, but is preferably low from the viewpoint of power consumption of the light emitting element. For example, an ITO substrate having a resistance of 300 Ω / □ or less functions as an element electrode. However, since a substrate of about 10 Ω / □ can be supplied at present, for example, 100 to 5 Ω / □, preferably 50 to 5 Ω. It is particularly desirable to use a low-resistance product of /. The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of 50 to 300 nm.

陽極 The anode in the organic electroluminescent element may have a bank (partition material). When an organic electroluminescent device is formed by a wet film formation method, an arbitrary layer can be obtained by dropping a composition for forming each layer or a composition for forming a light emitting layer in a bank and drying the composition.

Photolithography technology can be used for manufacturing the bank. As a bank material that can be used for photolithography, an inorganic material and an organic material can be used. As the inorganic material, for example, SiNx, SiOx and a mixture thereof, and as the organic material, for example, a positive resist Materials and negative resist materials can be used. Further, a patterning printing method such as a sputtering method, an inkjet method, gravure offset printing, reverse offset printing, and screen printing can also be used. In that case, a permanent resist material can be used. Further, the bank may have a multilayer structure, and different types of materials may be used.

Examples of the organic material used for the bank include polysaccharides and derivatives thereof, homopolymers and copolymers of ethylenic monomers having hydroxyls, biopolymer compounds, polyacryloyl compounds, polyesters, polystyrene, polyimide, polyamideimide, and poly (imide). Ether imide, polysulfide, polysulfone, polyphenylene, polyphenyl ether, 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, poly Fluorinated polymers hexafluoropropylene etc., fluoroolefins - hydrocarbonoxy olefin copolymer, fluorocarbon polymers, and the like, but is not so limited.

例 The following shows an example of a forming method using an organic material in the photolithography technology of the bank. A resin layer is formed by applying a material having liquid repellency to the functional layer forming composition such as the light emitting layer forming composition on the element substrate on which the electrodes are formed, and drying the applied material. By performing an exposure step and a development step on the resin layer using an exposure mask, a bank can be formed on the element substrate on which the electrodes are formed. Thereafter, if necessary, a process such as a washing / drying process with a solvent or an ultraviolet treatment may be performed to remove impurities on the surface of the bank in order to spread the composition for forming a functional layer evenly.

2-6 Substrate In the organic electroluminescent device, the substrate 101 serves as a support for the organic electroluminescent device 100, and is usually made of quartz, glass, metal, plastic, or the like. The substrate 101 is formed in a plate shape, a film shape, or a sheet shape depending on the purpose. For example, a glass plate, a metal plate, a metal foil, a plastic film, a plastic sheet, or the like is used. Among them, a glass plate and a plate made of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. For a glass substrate, soda lime glass, non-alkali glass, or the like is used, and the thickness only needs to be 0.2 mm or more, as long as it has a thickness sufficient to maintain mechanical strength. The upper limit of the thickness is, for example, 2 mm or less, preferably 1 mm or less. As for the material of the glass, alkali-free glass is preferable because it is preferable that the amount of ions eluted from the glass is small, but soda lime glass with a barrier coat such as SiO ₂ is also commercially available. it can. In addition, the substrate 101 may be provided with a gas barrier film such as a dense silicon oxide film on at least one side in order to enhance gas barrier properties. In particular, a plate, film, or sheet made of a synthetic resin having low gas barrier properties is used as the substrate 101. When used, it is preferable to provide a gas barrier film.

2-7. Manufacturing method of organic electroluminescent device Each layer constituting the organic electroluminescent device is formed by vapor deposition, resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination, printing, spin coating or casting, in which the materials constituting each layer are formed. It can be formed by forming a thin film by a method such as a coating method. The thickness of each layer thus formed is not particularly limited and can be appropriately set according to the properties of the material, but is usually in the range of 2 nm to 5000 nm. The film thickness can usually be measured with a quartz oscillation type film thickness measuring device or the like. When a thin film is formed using an evaporation method, the evaporation conditions vary depending on the type of material, the target crystal structure, association structure, and the like of the film. In general, the deposition conditions are as follows: heating temperature of the crucible for deposition +50 to + 400 ° C., vacuum degree of 10 ⁻⁶ to 10 ⁻³ Pa, deposition rate of 0.01 to 50 nm / sec, substrate temperature of −150 to + 300 ° C., and film thickness of 2 nm. It is preferable to set appropriately within a range of 5 μm.

Next, as an example of a method of fabricating an organic electroluminescent device, an anode / a hole injection layer / a hole transport layer / a host compound, a light-emitting layer containing a thermally activated delayed phosphor and a compound having a boron atom / electron transport A method for producing an organic electroluminescent device comprising a layer / electron injection layer / cathode will be described.

2-7-1. Evaporation Method A thin film of an anode material is formed on a suitable substrate by an evaporation method or the like to produce an anode, and then a thin film of a hole injection layer and a hole transport layer is formed on the anode. On this, a host compound, a thermally activated delayed phosphor and a compound having a boron atom are co-evaporated to form a thin film to form a light emitting layer, and an electron transport layer and an electron injection layer are formed on the light emitting layer, Further, a target organic electroluminescent element is obtained by forming a thin film made of a material for a cathode by a vapor deposition method or the like to form a cathode. In the above-described production of the organic electroluminescence device, the production order may be reversed, and the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode may be produced in this order. It is possible.
When forming the light emitting layer by a vapor deposition method, it is preferable to select and use a compound represented by the formula (ii) or a compound represented by the formula (2) as the third component. In particular, it is preferable to select and use a compound in which at least one of R ¹ to R ^{14 in} the formula (2) is a substituent. As the substituent herein, a preferable substituent in the above-mentioned third component can be employed. Among them, alkyl having 1 to 24 carbon atoms and optionally substituted diarylamino can be particularly preferably employed. When the light-emitting layer is formed using a compound having these substituents by an evaporation method, a corresponding compound having no substituent, a compound represented by the formula (i), a compound represented by the formula (iii), or The external quantum efficiency of the organic electroluminescent device is higher and the characteristics are better than when formed by a vapor deposition method using the compound represented by the formula (4).
When the light-emitting layer is formed by a vapor deposition method using the compound represented by the formula (i) or (iii) as the third component, it is preferable to employ a preferable substituent in the third component, It is particularly preferable to use a compound having an alkyl having 1 to 24 carbon atoms and an optionally substituted diarylamino. When the light-emitting layer is formed by a vapor deposition method using a compound having these substituents, the external quantum efficiency of the organic electroluminescent device is higher than when the light-emitting layer is formed by a vapor deposition method using a corresponding compound having no substituent. Long life and excellent characteristics.

2-7-2. When the composition for forming a light emitting layer is used, the film is formed by using a wet film forming method.

The wet film forming method generally forms a coating film through a coating step of applying a composition for forming a light emitting layer to a substrate and a drying step of removing a solvent from the applied composition for forming a light emitting layer. Depending on the difference in the coating process, the method using a spin coater can be changed to a spin coating method, a slit coating method using a slit coater, a gravure using a plate, offset, reverse offset, flexographic printing method, a method using an ink jet printer to an ink jet method, a mist form The spraying method is called a spray method. The drying step includes methods such as air drying, heating, and vacuum drying. The drying step may be performed only once, or may be performed a plurality of times using different methods and conditions. Further, for example, different methods such as firing under reduced pressure may be used in combination.

The wet film forming method is a film forming method using a solution, and for example, a partial printing method (ink jet method), a spin coating method or a casting method, a coating method, and the like. The wet film formation method does not require an expensive vacuum deposition apparatus unlike the vacuum deposition method, and can form a film under atmospheric pressure. In addition, the wet film forming method enables a large area and continuous production, which leads to a reduction in manufacturing cost.

On the other hand, when compared with the vacuum evaporation method, the wet film formation method is difficult to laminate. When a multilayer film is formed by a wet film formation method, it is necessary to prevent the dissolution of the lower layer by the composition of the upper layer, a composition having controlled solubility, crosslinking of the lower layer, and an orthogonal solvent (orthogonal solvent, which dissolve each other). No solvent). However, even with these techniques, it may be difficult to use a wet film forming method for coating all films.

2-7-3. Combination of Vacuum Deposition Method and Wet Film Forming Method In general, a method of manufacturing an organic electroluminescent element by using a wet film formation method for only some of the layers and using a vacuum deposition method for the remaining layers is adopted.

For example, a procedure for manufacturing an organic electroluminescent element by partially applying a wet film forming method is described below.
(Procedure 1) Film formation of anode by vacuum evaporation method (Procedure 2) Film formation of hole injection layer by wet film formation method (Procedure 3) Film formation of hole transport layer by wet film formation method (Procedure 4) Host compound Of a composition for forming a light emitting layer containing a heat-activated delayed phosphor and a compound having a boron atom by a wet film forming method (Step 5) Film formation of an electron transport layer by a vacuum deposition method (Step 6) Electron injection Layer Formation by Vacuum Deposition (Procedure 7) Cathode Deposition by Vacuum Deposition Through this procedure, anode / hole injection layer / hole transport layer / host material, heat-activated delayed phosphor, An organic electroluminescent device comprising a light emitting layer containing a compound having a boron atom / an electron transport layer / an electron injection layer / a cathode is obtained.

2-7-4. Manufacturing Example of Organic Electroluminescent Device by Ink Jet With reference to FIG. 6, a method of manufacturing an organic electroluminescent device on a substrate having a bank by using an inkjet method will be described. First, the bank (200) is provided on the electrode (120) on the substrate (110). In this case, a coating film (130) can be produced by dropping an ink droplet (310) from the inkjet head (300) between the banks (200) and drying it. This process is repeated until the next coating film (140) and further the light emitting layer (150) are formed, and the electron transport layer, the electron injection layer, and the electrode are formed using a vacuum deposition method. An organic electroluminescent device can be manufactured.

有機 The organic electroluminescent device thus manufactured is preferably covered with a sealing layer (not shown) to protect it from moisture and oxygen. For example, when moisture, oxygen, or the like enters from the outside, the light emitting function is impaired, and the luminous efficiency is reduced, and dark spots (dark spots) that do not emit light are generated. Further, the light emission life may be shortened. As the sealing layer, for example, an inorganic insulating material such as silicon oxynitride (SiON) having low permeability to moisture or oxygen can be used. Alternatively, the organic electroluminescent element may be sealed by attaching a sealing substrate such as a transparent glass or an opaque ceramic to an element substrate on which the organic electroluminescent element is formed via an adhesive.

2-8. Example of Application of Organic Electroluminescent Element The present invention can also be applied to a display device including the organic electroluminescent element, a lighting device including the organic electroluminescent element, and the like.
A display device or a lighting device equipped with the organic electroluminescent element can be manufactured by a known method such as connecting the organic electroluminescent element according to the present embodiment to a known driving device, and can be driven by direct current, pulse, or alternating current. Driving can be performed by appropriately using a known driving method such as driving.

Examples of the display device include a panel display such as a color flat panel display and a flexible display such as a flexible color organic electroluminescence (EL) display (for example, JP-A-10-335066, JP-A-2003-321546). Gazette, JP-A-2004-281086). Examples of the display method of the display include a matrix and / or segment method. Note that the matrix display and the segment display may coexist in the same panel.

In the matrix, pixels for display are two-dimensionally arranged such as in a lattice or mosaic, and a set of pixels displays a character or an image. The shape and size of the pixel depend on the application. For example, a square pixel having a side of 300 μm or less is normally used for displaying images and characters on a personal computer, a monitor, and a television. In the case of a large display such as a display panel, a pixel having a side of mm order is used. become. 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 displayed side by side. In this case, there are typically a delta type and a stripe type. The matrix may be driven by either a line-sequential driving method or an active matrix. The line-sequential driving has the advantage that the structure is simpler, but the active matrix is sometimes superior when the operating characteristics are taken into consideration.

In the segment method (type), a pattern is formed so as to display predetermined information, and a predetermined area emits light. For example, there are a time display and a temperature display on a digital clock or a thermometer, an operation state display of an audio device or an electromagnetic cooker, and a panel display of a car.

Illumination devices include, for example, illumination devices such as interior lighting, backlights of liquid crystal display devices (for example, JP-A-2003-257621, JP-A-2003-277741, and JP-A-2004-119211). Etc.). A backlight is mainly used for the purpose of improving the visibility of a display device that does not emit light, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display panel, a sign, and the like. In particular, in the case of a liquid crystal display device, particularly a backlight for a personal computer, for which thinning is an issue, the present embodiment is considered to be difficult to make thin because the conventional method is made up of a fluorescent lamp and a light guide plate. The backlight using the light emitting element according to the above is characterized by being thin and lightweight.

3. Light Emitting Layer Forming Composition The light emitting layer forming composition of the present invention is a composition for forming a light emitting layer of an organic electroluminescent device by a wet method. The composition for forming a light-emitting layer comprises a compound having at least one host compound as a first component, at least one heat-activated delayed phosphor as a second component, and at least one boron atom as a third component. And a composition containing at least one organic solvent as the fourth component. As the host compound, the thermally activated delayed fluorescent substance, and the compound having a boron atom, the compounds described in the description of the light emitting layer in the organic electroluminescent device can be used.

3-1. Organic solvent The composition for forming a light emitting layer of the present invention preferably contains at least one organic solvent. By controlling the evaporation rate of the organic solvent at the time of film formation, it is possible to control and improve the film formability and the presence / absence of defects in the coating film, surface roughness, and smoothness. In addition, during film formation using the inkjet method, the meniscus stability at the pinhole of the inkjet head can be controlled, and the ejection property can be controlled and improved. In addition, by controlling the drying rate of the film and the orientation of the derivative molecules, the electric characteristics, light-emitting characteristics, efficiency, and lifetime of the organic electroluminescent device having the light-emitting layer obtained from the light-emitting layer forming composition are improved. be able to.

3-1-1. Physical Properties of Organic Solvent The boiling point of at least one organic solvent contained as the fourth component in the composition for forming a light emitting layer is from 130 ° C. to 350 ° C., preferably from 140 ° C. to 300 ° C., more preferably from 150 ° C. to 250 ° C. More preferred. When the boiling point is higher than 130 ° C., it is preferable from the viewpoint of ink jet discharge properties. When the boiling point is lower than 350 ° C., it is preferable from the viewpoints of coating film defects, surface roughness, residual solvent and smoothness. From the viewpoints of good ink jetting properties, film forming properties, smoothness, and low residual solvent, a configuration containing two or more organic solvents is more preferable. On the other hand, in some cases, the composition may be in a solid state by removing a solvent from the composition for forming a light emitting layer in consideration of transportability and the like.

The composition for forming a light-emitting layer of the present invention contains, as a fourth component, a good solvent (GS) and a poor solvent (PS) for at least one of the compounds as the first component, the second component, and the third component. It is particularly preferred that the boiling point (BP _GS ) of the solvent ( _GS ) is lower than the boiling point (BP _PS ) of the poor solvent (PS).
By adding a poor solvent having a high boiling point, a good solvent having a low boiling point volatilizes first during the film formation, and the concentration of the components contained in the composition and the concentration of the poor solvent are increased, thereby promoting a rapid film formation. Thereby, a coating film with few defects, small surface roughness, and high smoothness can be obtained.

The difference in solubility (S _GS -S _PS ) is preferably at least 1%, more preferably at least 3%, even more preferably at least 5%. The difference in boiling points (BP _PS -BP _GS ) is preferably at least 10 ° C., more preferably at least 30 ° C., even more preferably at least 50 ° C.

After the film is formed, the organic solvent is removed from the coating film by a drying process such as vacuum, reduced pressure, and heating. In the case of performing heating, it is preferable to perform the heating at the highest glass transition temperature (Tg) + 30 ° C. or lower among the compounds as the first component, the second component, and the third component from the viewpoint of improving the coating film forming property. Further, from the viewpoint of reducing the residual solvent, it is preferable to heat at the lowest glass transition point (Tg) of −30 ° C. or higher among the compounds as the second component and the third component. Even when the heating temperature is lower than the boiling point of the organic solvent, the organic solvent is sufficiently removed because the film is thin. Further, drying may be performed a plurality of times at different temperatures, or a plurality of drying methods may be used in combination.

3-1-2. Specific examples of the organic solvent Examples of the organic solvent used in the composition for forming a light emitting layer include a hydrocarbon solvent, an alkylbenzene solvent, a phenyl ether solvent, an alkyl ether solvent, a cyclic ketone solvent, an aliphatic ketone solvent, and a simple solvent. Examples thereof include a cyclic ketone solvent, a solvent having a diester skeleton, and a fluorinated solvent. Specific examples include pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, and hexane-2- All, heptane-2-ol, octane-2-ol, decane-2-ol, dodecane-2-ol, cyclohexanol, α-terpineol, β-terpineol, γ-terpineol, δ-terpineol, terpineol (mixture), Ethylene glycol Methyl 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, -Chlorobenzotrifluoride, cumene, toluene, 2-chloro-6-fluorotoluene, 2-fluoroanisole, anisole, 2,3-dimethylpyrazine, bromobenzene, 4-fluoroanisole, 3-fluoroanisole, 3-trifluoro Methylanisole, mesitylene, 1,2,4-trimethylbenzene, t-butylbenzene, 2-methylanisole, phenetole, benzodioxole, 4-methylanisole, s-butylbenzene, 3-methylanisole, 4-fluoro- 3- Tylanisole, 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, diphenylether, 1-fluoro-3,5-dimethoxybenzene, benzoic Methyl, isopentylbenzene, 3,4-dimethylanisole, o-tolunitrile, n-amylbenzene, veratrol, 1,2,3,4-tetrahydronaphthalene, ethyl benzoate, n-hexylbenzene, propyl benzoate, cyclohexyl Benze , 1-methylnaphthalene, butyl benzoate, 2-methylbiphenyl, 3-phenoxytoluene, 2,2'-vitrile, dodecylbenzene, dipentylbenzene, tetramethylbenzene, trimethoxybenzene, trimethoxytoluene, 2,3-dihydro Benzofuran, 1-methyl-4- (propoxymethyl) benzene, 1-methyl-4- (butyloxymethyl) benzene, 1-methyl-4- (pentyloxymethyl) benzene, 1-methyl-4- (hexyloxymethyl) ) Benzene, 1-methyl-4- (heptyloxymethyl) benzenebenzyl butyl ether, benzyl pentyl ether, benzyl hexyl ether, benzyl heptyl ether, benzyl octyl ether, nitrobenzene, dimethylnitrobenzene, aminobiphenyl Diphenylamine and the like, but, but are not limited. Further, the solvent may be used alone or may be mixed.

As the organic solvent, an alkylbenzene-based solvent, a phenylether-based solvent, or a mixed solvent thereof is preferable. As the alkylbenzene-based solvent, cyclohexylbenzene is preferable, and as the phenylether-based solvent, 3-phenoxytoluene is preferable. A mixed solvent of cyclohexylbenzene and 3-phenoxytoluene is also preferable. At this time, the mass ratio of the two is not particularly limited, but may be, for example, 2: 8 to 8: 2, and is preferably 5: 5 to 8: 2.

3-2. The composition for forming an optional component light emitting layer may contain optional components as long as the properties are not impaired. Optional components include a binder and a surfactant.

3-2-1. The composition for forming a binder light emitting layer may contain a binder. The binder forms a film during film formation and bonds the obtained film to the substrate. In addition, it plays a role of dissolving, dispersing, and binding other components in the light emitting layer forming composition.

Examples of the binder used in the composition for forming a light emitting layer include acrylic resin, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylonitrile-ethylene-styrene copolymer (AES) resin, Ionomer, chlorinated polyether, diallyl phthalate resin, unsaturated polyester resin, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, Teflon (registered trademark), 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. Is but, but are not limited.

バインダー The binder used in the composition for forming a light emitting layer may be only one kind or a mixture of plural kinds.

3-2-2. The composition for forming a surfactant light emitting layer may contain, for example, a surfactant for controlling the film surface uniformity, the solvent affinity and the liquid repellency of the film surface of the light emitting layer forming composition. Surfactants are classified into ionic and nonionic according to the structure of the hydrophilic group, and further classified into alkyl, silicon and fluorine based on the structure of the hydrophobic group. Further, according to the molecular structure, they are classified into a monomolecular system having a relatively small molecular weight and a simple structure and a high molecular system having a large molecular weight and having side chains or branches. In addition, the composition is classified into a single system and a mixed system in which two or more surfactants and a base material are mixed from the composition. As surfactants that can be used in the composition for forming a light emitting layer, all kinds of surfactants can be used.

Examples of the surfactant include 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 Bake 182, BYK300, BYK306, BYK310, BYK320, BYK330, BYK342, BYK344, BYK346 (trade name, manufactured by BYK Japan KK), KP-341, KP-358, KP-368, KF-96-50CS, KF -50-100CS (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), Surflon SC-101, Surflon KH-40 (trade name, manufactured by Seimi Chemical Co., Ltd.), Futergent 222F, Futerge 251; FTX-218 (trade name, manufactured by Neos Corporation); EFTOP EF-351, EFTOP EF-352, EFTOP EF-601, EFTOP EF-801, EFTOP EF-802 (trade name, Mitsubishi Materials Corporation) 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 Corporation), fluoroalkyl benzene sulfonate, fluoroalkyl carboxylate, fluoroalkyl polyoxyethylene ether, fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl sulfonate, diglycerin tetrakis (Fluoroa Alkylpolyoxyethylene ether), fluoroalkyltrimethylammonium salt, fluoroalkylaminosulfonate, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene laurate, polyoxyethylene oleate Eate, polyoxyethylene stearate, polyoxyethylene laurylamine, sorbitan laurate, sorbitan palmitate, sorbitan stearate, sorbitan oleate, sorbitan fatty acid ester, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxy Ethylene sorbitan stearate, polyoxyethylene sorbitan oleate, polyoxyethylene naph Ethers, it may be mentioned alkyl benzene sulfonates and alkyl diphenyl ether disulfonate salt.
One surfactant may be used alone, or two or more surfactants may be used in combination.

3-3. Composition and Properties of Light Emitting Layer Forming Composition In the light emitting layer forming composition of the present invention, the first component, the second component, and the third component have excellent solubility, film formability, wet coatability, and thermal stability. A compound that satisfies at least one of properties and in-plane orientation is selected. In addition, from the viewpoints of excellent solubility, film forming property, wet coating property, and in-plane orientation, alkyl having 1 to 24 carbon atoms, diarylamino, cycloalkyl having 5 to 24 carbon atoms, and cycloalkyl having 6 to 24 carbon atoms are preferable. It is preferable to select a compound substituted with aryl and heteroaryl having 5 to 24 carbon atoms.

化合物 As the first component, it is preferable to select a compound having phenylene, triazine, pyridine, carbazole, dibenzofuran or dibenzothiophene having a substituent at the m-position in the molecule. As the second component, a compound having alkyl or cycloalkyl in the molecule is preferable from the viewpoint of solubility and film formability, and a rod-like molecule having a high oversight is preferable from the viewpoint of efficiency. Compounds having azole, thiadiazole and triazole in the molecule are preferred, and Formula 2PXZ-TAZ is preferred. As the third component, a compound having alkyl or cycloalkyl in the molecule is preferable from the viewpoint of solubility and film-forming properties, and a rod-like molecule having a high overhead is preferable from the viewpoint of efficiency. The compound represented by 2) is preferable, and B2N4-0230 / S-M1, B2N4-0220 / S-M1, B2N4-0211 / S-M1, BN2BNO-0230 / S-M1, and B2O2N2-0220 / S-M1 It is preferred to select a compound that is

The content of each component in the composition for forming a light emitting layer of the present invention is not particularly limited, but the content of the first component is preferably based on the total mass of the first component, the second component, and the third component. It is from 40% by mass to 98.999% by mass, more preferably from 50% by mass to 99.99% by mass, still more preferably from 60% by mass to 94.9% by mass. The content of the second component is 1% by mass to 60% by mass, more preferably 2% by mass to 50% by mass, based on the total mass of the first component, the second component and the third component. Preferably it is 5% by mass to 30% by mass. The content of the third component is preferably 0.001% by mass to 30% by mass, more preferably 0.01% to 20% by mass, based on the total mass of the first component, the second component and the third component. And more preferably 0.1 to 10% by mass. The above range is preferable, for example, in that the density quenching phenomenon can be prevented.

Further, when the composition for forming a light emitting layer of the present invention contains an organic solvent, the content of each of the first component, the second component and the third component is determined by the good dissolution of each component in the composition for forming a light emitting layer. , Storage stability and film-forming properties, and good film quality of a coating film obtained from the composition for forming a light-emitting layer, and also good dischargeability when using an inkjet method, produced using the composition. It may be determined from the viewpoints of good electric characteristics, light-emitting characteristics, efficiency, and life of the organic electroluminescent element having the light-emitting layer. For example, from the above viewpoint, the first component is 40 to 98.999% by mass, and the second component is 1% by mass based on the total mass of the first component, the second component, and the third component of the composition for forming a light emitting layer. % To 60% by mass, and the third component is preferably 0.001% to 30% by mass. More preferably, the first component is 50% to 97.9% by mass, and the second component is 2% by mass, based on the total mass of the first, second and third components of the composition for forming a light emitting layer. And the third component is 0.01 to 20% by mass. More preferably, the first component is 60% by mass to 94.9% by mass, and the second component is 5% by mass, based on the total mass of the first component, the second component, and the third component of the composition for forming a light emitting layer. -30% by mass, and the third component is 0.1-10% by mass.

The content of each component in the composition for forming a light-emitting layer of the present invention is good solubility, storage stability and film formability of each component in the composition for forming a light-emitting layer, and the composition for forming a light-emitting layer. Good film quality of the coating film obtained from the above, and also good ejection property when using the ink jet method, good electric characteristics and light emitting characteristics of the organic electroluminescent element having the light emitting layer manufactured using the composition It may be determined from the viewpoints of efficiency, life, and life. For example, from the viewpoint described above, the first component is included in an amount of 0.0998% by mass to 4.0% by mass, and the second component is included in the total mass of the light emitting layer forming composition. On the other hand, 0.0001% by mass to 2.0% by mass, the third component is 0.0001% by mass to 2.0% by mass, and the fourth component is the light emitting layer with respect to the total mass of the composition for forming a light emitting layer. It is preferably from 90.0% to 99.9% by mass relative to the total mass of the forming composition.

More preferably, the first component is 0.17% by mass to 4.0% by mass with respect to the total mass of the light emitting layer forming composition, and the second component is with respect to the total mass of the light emitting layer forming composition. 0.03% by mass to 1.0% by mass, the third component being 0.03% by mass to 1.0% by mass, and the fourth component being the composition for forming the light emitting layer, based on the total mass of the composition for forming the light emitting layer. 93.0% by mass to 99.77% by mass with respect to the total mass of the product. More preferably, the first component is 0.25% by mass to 2.5% by mass with respect to the total mass of the light emitting layer forming composition, and the second component is the total mass of the light emitting layer forming composition. 0.05% to 0.5% by mass, the third component being 0.05% to 0.5% by mass, and the fourth component being the composition for forming the light emitting layer, based on the total mass of the composition for forming the light emitting layer. 96.5% by mass to 99.7% by mass relative to the total mass of the product. In another preferred embodiment, the first component is 0.095% by mass to 4.0% by mass, based on the total mass of the light emitting layer forming composition, and the second component is the total mass of the light emitting layer forming composition. On the other hand, 0.003% by mass to 1.0% by mass, the third component is 0.002% by mass to 1.0% by mass, and the fourth component is the light emitting layer with respect to the total mass of the composition for forming a light emitting layer. It is 92.0% by mass to 99.9% by mass relative to the total mass of the forming composition.

The composition for forming a light-emitting layer can be produced by appropriately selecting the above-mentioned components by stirring, mixing, heating, cooling, dissolving, dispersing and the like by a known method. After the preparation, filtration, degassing (also referred to as degassing), ion exchange treatment, inert gas replacement / sealing treatment, and the like may be appropriately selected and performed.

(4) As for the viscosity of the composition for forming a light emitting layer, the higher the viscosity, the better the film formability and the good ejection property when an inkjet method is used. On the other hand, the lower the viscosity, the easier it is to form a thin film. For this reason, the viscosity of the composition for forming a light emitting layer is preferably from 0.3 mPa · s to 3 mPa · s at 25 ° C., more preferably from 1 mPa · s to 3 mPa · s. In the present invention, the viscosity is a value measured using a conical plate type rotary viscometer (cone plate type).

(4) The lower the surface tension of the composition for forming a light-emitting layer, the better the film formability and the coating film without defects. On the other hand, the higher the value, the better the ink jetting property can be obtained. For this reason, the viscosity of the composition for forming a light emitting layer preferably has a surface tension at 25 ° C. of 20 mN / m to 40 mN / m, and more preferably 20 mN / m to 30 mN / m. In the present invention, the surface tension is a value measured using the hanging drop method.

Hereinafter, the present invention will be described specifically with reference to Examples. The materials, processing contents, processing procedures, and the like described below can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples described below.
Below, the synthesis example of the compound used in the Example is shown.

1. Synthetic example of compound (1)
Compound (ED1): N ⁷ , N ⁷ , N ¹³ , N ¹³ , 5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b, Synthesis of 20b-divorazinaphtho [3,2,1-de: 1 ′, 2 ′, 3′-jk] pentacene-7,13-diamine

[First stage]
Under a nitrogen atmosphere, 1,3-dibromobenzene (25.0 g, 106 mmol), aniline (20.3 ml, 223 mmol), tris (dibenzylideneacetone) dipalladium (0) (Pd ₂ (dba) ₃ ) (971 mg, 1 .06 mmol), 2,2′-bis (diphenylphosphino) -1,1′-binaphthyl (BINAP: 1.98 g, 3.18 mmol), NaOtBu (25.5 g, 265 mmol) and toluene (400 ml). The flask was heated to 110 ° C. and stirred for 18 hours. The reaction solution was cooled to room temperature, filtered using silica gel (eluent: toluene), and the solvent was distilled off under reduced pressure to obtain a crude product. After dissolving the obtained crude product in toluene, an appropriate amount was distilled off under reduced pressure, and hexane was added for reprecipitation, whereby N ¹ , N ³ -diphenylbenzene-1,3-diamine (16.5 g, (60% yield) as a white solid.

The structure of the obtained compound was confirmed by NMR spectrum.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.63 (s, 2H), 6.60 (dd, 2H), 6.74 (t, 1H), 6.90 (t, 2H), 7 .06 (d, 4H), 7.12 (t, 1H), 7.24 (dt, 4H).

[2nd stage]
Under a nitrogen atmosphere, 1,3-dibromo-5-chlorobenzene (8.11 g, 30 mmol), diphenylamine (10.1 g, 60 mmol), Pd ₂ (dba) ₃ (550 mg, 0.6 mmol), 2-dicyclohexylphenylphosphino A flask containing -2 ', 6'-dimethoxydiphenyl (SPhos: 0.493 g, 1.2 mmol), sodium tert-butoxide (NaOtBu) (8.60 g, 90 mmol) and toluene (300 ml) was heated to 80 ° C. And stirred for 15 hours. The reaction solution was cooled to room temperature, filtered using silica gel (eluent: toluene), and the solvent was distilled off under reduced pressure to obtain a crude product. After dissolving the obtained crude product in toluene, the solution is distilled off under reduced pressure to prepare a saturated solution, and hexane is added thereto for reprecipitation to give 5-chloro-N ¹ , N ¹ , N ³ , N ^3. -Tetraphenylbenzene-1,3-diamine (5.66 g, 43% yield) was obtained as a white solid.

The structure of the obtained compound was confirmed by NMR spectrum.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 6.56 (d, 2H), 6.64 (t, 1H), 7.00 (t, 4H), 7.05 (d, 8H), 7 .21 (dd, 8H).

[3rd stage]
Under a nitrogen atmosphere, N ¹ , N ³ -diphenylbenzene-1,3-diamine (1.34 g, 5.1 mmol) synthesized in the first step, 5-chloro-N ¹ , N ¹ , synthesized in the second step, N ³ , N ³ -tetraphenylbenzene-1,3-diamine (4.80 g, 11 mmol), Pd ₂ (dba) ₃ (0.140 g, 0.15 mmol), tri-tert-butylphosphine (60.7 mg, 0.30 mmol), a flask containing NaOtBu (1.47 g, 15 mmol) and toluene (200 ml) were heated to 110 ° C. and stirred for 8 hours. The reaction solution was cooled to room temperature, filtered using silica gel (eluent: toluene), and the solvent was distilled off under reduced pressure to obtain a crude product. By washing the obtained crude product in order of hexane and methanol, N ¹ , N ¹ ′-(1,3-phenylene) bis (N ¹ , N ³ , N ³ , N ⁵ , N ⁵ -pentaphenyl) Benzene-1,3,5-triamine (4.80 g, 87% yield) was obtained as a white solid.

The structure of the obtained compound was confirmed by NMR spectrum.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 6.38 (d, 4H), 6.41 (t, 2H), 6.58 (dd, 2H), 6.70 (t, 1H), 6 .88-6.90 (m, 14H), 6.85 (t, 1H), 6.99 (d, 16H), 7.08-7.15 (m, 20H).

[Stage 4]
N ¹ , N ¹ ′-(1,3-phenylene) bis (N ¹ , N ³ , N ³ , N ⁵ , N ⁵ -pentaphenylbenzene-1,3,5-triamine (3.24 g, 3.0 mmol) ) And orthodichlorobenzene (400 ml) were added with boron tribromide (1.13 ml, 12 mmol) at room temperature under a nitrogen atmosphere at the end of the dropwise addition, and the mixture was heated to 180 ° C and stirred for 20 hours. Then, the mixture was cooled again to room temperature, N-diisopropylethylamine (7.70 ml, 45 mmol) was added, and the mixture was stirred until the exotherm stopped, and then the reaction solution was distilled off under reduced pressure at 60 ° C. to obtain a crude product. The obtained crude product was washed with acetonitrile, methanol and toluene in this order, purified by silica gel column chromatography (eluent: toluene), and the crude product was purified by o-dichloromethane. Performed twice recrystallized chlorobenzene under a reduced pressure of then 1 × ¹⁰ -4 mmHg, by performing the sublimation purification at 440 ° C., the compound (ED1) to give 1.17 g.

The structure of the obtained compound was confirmed by NMR spectrum.
¹ H-NMR (400 MHz, CDCl ₃ ): δ = 5.72 (s, 2H), 5.74 (s, 2H), 5.86 (s, 1H), 6.83 (d, 2H), 6 .88-6.93 (m, 12H), 7.05 (t, 8H), 7.12-7.19 (m, 6H), 7.24-7.26 (m, 4H), 7.05 (D, 4H), 7.12 (dd, 8H), 7.12-7.19 (m, 6H), 7.32 (d, 4H), 7.38 (dd, 2H), 7.42 ( t, 2H), 7.46 (dd, 2H), 7.47 (dd, 4H), 9.30 (d, 2H), 10.5 (s, 1H).

¹³ C-NMR (101 MHz, CDCl ₃ ): 99.5 (2C + 2C), 103.4 (1C), 116.8 (2C), 120.0 (2C), 123.1 (4C), 125.3 ( 8C), 127.1 (2C), 127.6 (2C), 128.5 (8C), 129.6 (4C), 129.8 (4C), 130.2 (4C + 2C), 130.3 (4C) ), 135.0 (2C), 142.1 (2C), 142.5 (2C), 143.3 (1C), 146.8 (4C), 147.9 (2C + 2C), 148.0 (2C) , 150.1 (2C), 151.1 (2C).

Synthesis example (2)
Compound (1-41): 2,12-di-t-butyl-5,9-bis (4- (t-butyl) phenyl) -7-methyl-5,9-dihydro-5,9-diaza-13b -Synthesis of Boranaphtho [3,2,1-de] anthracene

Compound (1-41) was synthesized according to the method described in “Synthesis Example (32)” of International Publication No. WO 2015/102118.

Hereinafter, in Synthesis Examples (1-2) to (1-4) and (1-9) to (1-14), each compound was synthesized using the same method as in Synthesis Example (1-1) described above. .

Synthesis example (3)
Compound (1-31): 2,12-di-t-butyl-5,9-bis (4- (t-butyl) phenyl) -5,9-dihydro-5,9-diaza-13b-boranaphtho [3 Of [2,1,1-de] anthracene

Synthesis example (4)
Compound (1-53): 2,12-di-t-butyl-5,9-bis (4- (t-butyl) phenyl) -7- (9H-carbazol-9-yl) -5,9-dihydro Synthesis of -5,9-diaza-13b-boranaphtho [3,2,1-de] anthracene

Synthesis example (5)
Compound (1-37): 3,12-di-t-butyl-9- (4- (t-butyl) phenyl) -5- (3,5-di-t-butylphenyl) -5,9-dihydro Synthesis of -5,9-diaza-13b-boranaphtho [3,2,1-de] anthracene

Synthesis example (6)
Compound (1-46): 3,12-di-t-butyl-9- (4- (t-butyl) phenyl) -5- (3,5-di-t-butylphenyl) -7-methyl-5 Of 9,9-dihydro-5,9-diaza-13b-boranaphtho [3,2,1-de] anthracene

Compound (1-46) was synthesized according to the method described in “Synthesis Example (32)” of International Publication No. WO 2015/102118.

Synthesis example (7)
Compound (1-50): 2,12-di-t-butyl-N, N, 5,9-tetrakis (4- (t-butyl) phenyl) -5,9-dihydro-5,9-diaza-13b Of Boranaphtho [3,2,1-de] anthracene-7-amine

Compound (1-50) was synthesized according to the method described in “Synthesis Example (32)” of International Publication No. WO 2015/102118.

Synthesis example (8)
Compound (1-49): 2,12-di-t-butyl-5,9-bis (4- (t-butyl) phenyl) -N, N-diphenyl-5,9-dihydro-5,9-diaza Synthesis of -13b-boranaphtho [3,2,1-de] anthracene-7-amine

Compound (1-49) was synthesized according to the method described in “Comparative Synthesis Example (1)” of JP-A-2016-88927.

Synthesis example (9)
Compound of the formula (1-340): 15,15-dimethyl-N, N-diphenyl-15H-5,9-dioxa-16b-bolinedeno [1,2-b] naphtho [1,2,3-fg] anthracene Synthesis of 13-amine

Compound (1-340) was synthesized according to the method described in “Synthesis Example (4)” of International Publication No. WO 2017/126443.

Synthesis example (10)
Compound of formula (1-351): 5-([1,1′-biphenyl] -4-yl) -15,15-dimethyl-N, N, 2-triphenyl-5H, 15H-9-oxa-5 -Synthesis of aza-16b-bolinedeno [1,2-b] naphtho [1,2,3-fg] anthracene-13-amine

Compound (1-351) was synthesized according to the method described in “Synthesis Example (5)” of International Publication WO2017 / 126443.

2.Evaluation of basic physical properties
Preparation of Samples When evaluating the absorption and emission characteristics (fluorescence and phosphorescence) of the compound to be evaluated, evaluate only the compound to be evaluated in a thin film, or place the compound to be evaluated in an appropriate matrix material. It was dispersed and made into a thin film and evaluated.

When thinning only the compound to be evaluated for evaluation, the compound was vacuum-deposited on a glass substrate with a thickness of 30 to 100 nm to obtain a sample.
A commercially available PMMA (polymethyl methacrylate) was used as a matrix material when the compound to be evaluated was dispersed in an appropriate matrix material. In this example, a sample was prepared by dissolving PMMA and a compound to be evaluated in toluene and then forming a thin film having a thickness of 10 nm on a transparent support substrate (10 mm × 10 mm) made of quartz by spin coating. . The concentration of the sample was 1% by mass.

The measurement of the absorption spectrum of the evaluation sample for the absorption characteristics and the emission characteristics was performed using an ultraviolet-visible-near-infrared spectrophotometer (UV-2600, Shimadzu Corporation). The fluorescence spectrum and phosphorescence spectrum of the sample were measured using a spectrofluorometer (F-7000, manufactured by Hitachi High-Tech Co., Ltd.).

For the measurement of the fluorescence spectrum, the photoluminescence was measured by exciting at an appropriate excitation wavelength of about 340 nm at room temperature. For the measurement of the phosphorescence spectrum, the sample was immersed in liquid nitrogen (temperature 77 K) using an attached cooling unit. In order to observe the phosphorescence spectrum, the delay time from the irradiation of the excitation light to the start of the measurement was adjusted using an optical chopper. The sample was excited at the appropriate excitation wavelength and photoluminescence was measured.

について For each compound of the third component, the Stokes shift was determined from the difference between the peak top of the absorption spectrum and the peak top of the emission spectrum at room temperature.

The fluorescence quantum yield (PLQY) was measured using an absolute PL quantum yield measurement device (C9920-02G, manufactured by Hamamatsu Photonics KK).
Furthermore, the time until the light emission intensity became 50% of the initial value was measured by continuously applying a direct current, and the device life (LT50) was evaluated.

Evaluation of Fluorescence Lifetime (Delayed Fluorescence) The fluorescence lifetime was measured at 300K using a fluorescence lifetime measuring device (C11367-01, manufactured by Hamamatsu Photonics KK). Specifically, at the maximum emission wavelength measured at an appropriate excitation wavelength, a light emission component having a short fluorescence lifetime and a light emission component having a long fluorescence lifetime were observed. In the measurement of the fluorescence lifetime of a general organic electroluminescent material that emits fluorescence at room temperature, a slow emission component involving a triplet component derived from phosphorescence due to deactivation of the triplet component due to heat is not observed. rare. When a slow emission component is observed in the compound to be evaluated, it indicates that triplet energy having a long excitation lifetime has been transferred to singlet energy by thermal activation and observed as delayed fluorescence. Here, the fluorescence lifetime of the delayed fluorescence was measured as Tau (Delay).

Calculation of E (S, Sh), E (T, Sh), E (S, PT), E (T, PT) and ΔE (ST) Singlet excitation energy level E (S, Sh) is a fluorescence spectrum E (S, Sh) = 1240 / B _Sh from the wavelength B _Sh (nm) at the intersection of the tangent passing through the shoulder on the peak short wavelength side and the baseline. Further, the triplet excitation energy level E (T, Sh) is obtained from the wavelength C _Sh (nm) at the intersection of the tangent passing through the shoulder on the peak short wavelength side of the phosphorescence spectrum and the base line, and E (T, Sh) = Calculated as 1240 / C _Sh . Further, the maximum peak emission wavelength of the fluorescence spectrum was also measured.
In this specification, the singlet excitation energy level of the first component is E (1, S, Sh), the singlet excitation energy level of the second component is E (2, S, Sh), and the singlet excitation energy level is the single component. Term is E (3, S, Sh), the triplet excitation energy level of the first component is E (1, T, Sh), and the triplet excitation energy level of the second component is E (2, T, Sh), and the triplet excitation energy level of the third component is denoted as E (3, T, Sh).

ΔE (ST) is the energy difference between E (S, Sh) and E (T, Sh). ΔE (ST) = E (S, Sh) −E (T, Sh). ΔE (ST) is, for example, “Purely organic electroluminescent material realizing 100% conversion from electricity to light”, H. Kaji, H. Suzuki, T. Fukushima, K. Shizu, K. Katsuaki, S. Kubo, T Komino, H. Oiwa, F. Suzuki, A. Wakamiya, Y. Murata, C. Adachi, Nat. Commun. 2015, 6, 8476.
In this specification, ΔE (ST) of the first component is ΔE (1, ST, Sh), ΔE (ST) of the second component is ΔE (2, ST, Sh), and ΔE (ST) of the third component is ΔE (ST). ΔE (3, ST, Sh) is displayed.

The results of measuring the basic physical properties of the compounds of the first component used in the examples and comparative examples are shown in the following table.

The results of measuring the basic physical properties of the compounds of the second component used in Examples and Comparative Examples are shown in the following table.

The results of measuring the basic physical properties of the compounds of the third component used in Examples and Comparative Examples are shown in the following table. In the table, the phosphorescence spectrum of R-BD2 could not be observed, suggesting that E (3, T, Sh) was very low. In the table, "ND" indicates that no measurement was performed.

The following table shows the results of measuring the maximum peak emission wavelength of the fluorescence spectrum of the main compound.

3. Fabrication of Organic Electroluminescent Device An organic electroluminescent device was fabricated, and a voltage was applied to measure current density, luminance, chromaticity, and external quantum efficiency. First, the following configuration A (Table 1) was selected and evaluated as the configuration of the manufactured organic electroluminescent device. Configuration A is a configuration suitable for a heat-activated delayed fluorescence material. Configuration A is an element configuration that can be expected to have high efficiency as shown in the literature (Adv. Mater. 2016, 28, 2777-2781). However, the application of the compound of the present invention is not limited to these structures, and the film thickness of each layer and constituent materials can be appropriately changed depending on the basic physical properties of the compound of the present invention.

<Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-4>
A 26 mm × 28 mm × 0.7 mm glass substrate (manufactured by OptoScience Corp.), which was formed by polishing ITO formed to a thickness of 200 nm by sputtering to 50 nm, was used as a transparent support substrate. This transparent support substrate was fixed to a substrate holder of a commercially available vapor deposition device (manufactured by Choshu Sangyo Co., Ltd.), and NPD, TcTa, mCP, the first component (mCBP), the second component (the compounds described in the table below), A tantalum evaporation boat containing the third component (ED1) and TSPO1, respectively, and an aluminum nitride evaporation boat containing LiF and aluminum, respectively, were mounted.

The following layers were sequentially formed on the ITO film of the transparent support substrate. The pressure in the vacuum chamber was reduced to 5 × 10 ⁻⁴ Pa. First, NPD was heated to deposit a film to a thickness of 40 nm, and then TcTa was heated to deposit a film to a thickness of 15 nm to form two layers. Was formed. Next, the mCP was heated to be deposited to a thickness of 15 nm to form an electron blocking layer. Next, the first component, the second component, and the third component described in the table below were simultaneously heated and co-evaporated to a thickness of 20 nm to form a light emitting layer. The deposition rate was adjusted so that the mass ratio of the first component, the second component, and the third component was as shown in the table below. Next, TSPO1 was heated and evaporated to a thickness of 30 nm to form an electron transport layer. The deposition rate of each of the above layers was 0.01 to 1 nm / sec. Thereafter, the cathode is formed by heating LiF so as to have a film thickness of 1 nm at a deposition rate of 0.01 to 0.1 nm / sec, and then heating aluminum so as to have a film thickness of 100 nm. Thus, an organic electroluminescent device was obtained. At this time, the deposition rate of aluminum was adjusted to be 1 nm to 10 nm / sec.

For each of the manufactured organic electroluminescent devices of Examples 1-1 to 1-3 and Comparative examples 1-1 to 1-4, a direct current voltage was applied using the ITO electrode as an anode and the aluminum electrode as a cathode, and the fluorescence peak wavelength, The value width and external quantum efficiency were measured. The results are shown in the table below. The relationship of E (S, Sh) and the relationship of E (T, Sh) in the table below show the magnitude relationship of the energy levels of the first component, the second component, and the third component. For example, in the relationship of E (S, Sh), the one indicated as “1> 2> 3” is E (1, S, Sh)> E (2, S, Sh)> E (3, S, Sh). Sh).

The emission colors of Examples 1-1 to 1-3, Comparative Examples 1-3 and Comparative Examples 1-4 were deep blue (deep blue), and Comparative Examples 1-1 were sky blue (sky blue) to greenish. Blue (Greenish blue), and Comparative Example 1-2 was blue (blue).

When Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-4 are compared, E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) When the first component, the second component, and the third component satisfying the relationship were used in combination in the light emitting layer, it was confirmed that the color tone was good, the half width was narrow, and the external quantum yield was high. When the third component was not used in the light emitting layer, the half value width was widened and the external quantum efficiency was reduced. When the second component was not used in the light emitting layer, the external quantum efficiency was reduced. Further, the characteristics given by the structure of the second component used in the light emitting layer are different, and it was confirmed that Example 1-1 using 2PXZ-TAZ having a DAD type structure gave the highest external quantum efficiency. Was.

<Examples 1-4 to 1-11 and Comparative Example 1-5>
The organic electroluminescent devices of Examples 1-4 to 1-11 and Comparative Example 1-5 were manufactured in the same procedure as Example 1-1, except that the materials described in the table below were used. did. In Example 1-4, Comparative Example 1-5, and Example 1-5, the compound of the third component was changed. In Examples 1-6 to 1-11, the compound of the first component was changed.

For each of the fabricated organic electroluminescent devices of Examples 1-4 to 1-11 and Comparative Example 1-5, a DC voltage was applied using the ITO electrode as the anode and the aluminum electrode as the cathode in the same manner as in Example 1-1, and the fluorescent light was emitted. The peak wavelength, half width and external quantum efficiency were measured. The results are shown in the table below.

In Examples 1-4 to 1-11 and Comparative Example 1-5, all satisfy the relational expression of E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh). Although the first component, the second component, and the third component are used in combination in the light-emitting layer, compared to Comparative Example 1-5 using R-BD2 which is a compound having no boron atom as the third component, In Examples 1-4 to 1-11 using compounds having a boron atom as the three components, the half-value width was smaller and the external quantum efficiency was higher.
Further, compared to Example 1-5 using RD-3 which is the compound of formula (i) as the third component, RD-1 which is the compound of formula (ii) corresponding to the dimer of formula (i) In Examples 1-4 and 1-6 to 1-11 using ED1 as the third component, the half width was smaller and more preferable characteristics were exhibited. Further, among the embodiments, in the embodiments 1-4 and 1-6 to 1-11 in which E (1, T, Sh)> E (3, T, Sh)> E (2, T, Sh). Is smaller than Example 1-5 in which E (1, T, Sh)> E (2, T, Sh)> E (3, T, Sh), and the external quantum efficiency is equal to or more than that of Example 1-5. Met. In particular, when ED1 having a structure substituted with a diarylamino group is used as the third component, the ED1 has a particularly small half-width, a high external quantum efficiency, and further excellent characteristics as an organic electroluminescent device. It was confirmed that.

<Examples 1-12 to 1-15 and Comparative Example 1-6>
The organic electroluminescent devices of Examples 1-4 to 1-11 and Comparative Example 1-5 were manufactured in the same procedure as Example 1-1, except that the materials described in the table below were used. did. In these specific examples, the compound of the second component is changed.

For each of the fabricated organic electroluminescent devices of Examples 1-12 to 1-15 and Comparative Example 1-6, a DC voltage was applied using the ITO electrode as the anode and the aluminum electrode as the cathode in the same manner as in Example 1-1, and the fluorescent light was emitted. The peak wavelength, half width and external quantum efficiency were measured. The results are shown in the table below.

An embodiment in which a first component, a second component, and a third component satisfying a relationship of E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) are used in combination in a light emitting layer. Examples 1-12 to 1-15 have a half-width compared to Comparative Example 1-6 in which the relationship of E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) is not satisfied. And the external quantum yield was high. The results of Examples 1-12 to 1-15 show that good characteristics are maintained even when the type of the second component is changed.

<Examples 1-16 to 1-26>
Using the materials described in the table below, the electron transport layer was changed to a configuration B by forming two layers of an electron transport layer 1 having a thickness of 10 nm and an electron transport layer 2 having a thickness of 20 nm. According to the same procedure as in 1-1, the organic electroluminescent devices of Examples 1-16 to 1-26 were manufactured. The electron transporting layer 2 of Example 1-23 was formed by heating BPy-TP2 and Liq and vapor-depositing them to a thickness of 20 nm so that the respective ratios became 7: 3 by mass. In addition, the electron transport layer 2 of Example 1-24 was formed by heating SF3-TRZ and Liq and vapor-depositing the film to a thickness of 20 nm so that the respective ratios became 7: 3 by mass.

For each of the fabricated organic electroluminescent devices of Examples 1-16 to 1-26, a DC voltage was applied using the ITO electrode as the anode and the aluminum electrode as the cathode in the same manner as in Example 1-1, and the fluorescence peak wavelength, half width, The external quantum efficiency was measured, and the device lifetime (LT50) was also measured. The results are shown in the table below.

において In Examples 1-16 to 1-26, it was confirmed that the organic electroluminescent device having two electron transport layers also exhibited good characteristics. In addition, it was confirmed that all the organic electroluminescent elements had a sufficient element life.

<Examples 1-27 to 1-55 and Comparative Example 1-7>
The organic electroluminescence of Configuration B of Examples 1-27 to 1-55 and Comparative Example 1-7 was conducted in the same manner as in Example 1-14, except that the materials described in the table below were used. The device was manufactured. In Examples 1-27 to 1-55, various compounds represented by the formula (ii) were evaluated as the third component.

For each of the prepared organic electroluminescent devices of Examples 1-27 to 1-55 and Comparative Example 1-7, a DC voltage was applied using the ITO electrode as the anode and the aluminum electrode as the cathode in the same manner as in Example 1-16, and the fluorescent light was emitted. The peak wavelength, half width, external quantum efficiency, and device lifetime (LT50) were measured. The results are shown in the table below.

In Examples 1-27 to 1-55 and Comparative Example 1-7, the first component that satisfies E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) , The second component and the third component are used in combination in the light-emitting layer. However, compared to Comparative Example 1-7 using R-BD2 which is a compound having no boron atom as the third component, In Examples 1-27 to 1-55 using the compound having a boron atom, the half width was smaller, the external quantum efficiency was higher, and the device life was longer.
In Examples 1-27 to 1-38 and 1-40 to 1-55, the relational expressions of E (1, T, Sh)> E (3, T, Sh) ≧ E (2, T, Sh) are used. Therefore, the device lifetime was long and the external quantum efficiency was high. On the other hand, among organic electroluminescent elements in which E (1, T, Sh)> E (2, T, Sh)> E (3, T, Sh), Example 1-39 shows ΔE (3, ST, Sh). ) Was sufficiently low at 0.08 eV, so that the half width was small and the external quantum efficiency was high. On the other hand, in Comparative Example 1-7, no phosphorescence was emitted from the third component, R-BD2, and ΔE (3, ST, Sh) was large, so that the half width was large and the external quantum efficiency was low. .
Examples 1-27 to 1-55 all have a structure represented by the formula (ii). Since the skeleton of the formula (i) has a dimerized multimeric skeleton and the skeleton has a symmetrical shape, it is considered to show good characteristics.

<Examples 1-56 to 1-72 and Comparative Example 1-8>
The organic electroluminescence of Configuration B of Examples 1-56 to 1-72 and Comparative Example 1-8 was performed in the same manner as in Example 1-14, except that the materials described in the following table were used. The device was manufactured. In Examples 1-56 to 1-72, various compounds represented by the formula (i) were evaluated as the third component.

For each of the fabricated organic electroluminescent devices of Examples 1-56 to 1-72 and Comparative Example 1-8, a DC voltage was applied using the ITO electrode as the anode and the aluminum electrode as the cathode in the same manner as in Example 1-16, and the fluorescent The peak wavelength, half width, external quantum efficiency, and device lifetime (LT50) were measured. Examples 1-56 to 1-66 and Comparative Example 1 where E (3, T, Sh) is less than 0.3 eV and ΔE (2, ST, Sh) is greater than ΔE (3, ST, Sh). The measurement results of -8 are shown in the following table. Further, the measurements of Examples 1-67 to 1-72 in which E (3, T, Sh) is 0.3 eV or more and ΔE (3, ST, Sh) is larger than ΔE (2, ST, Sh). The results are shown in the table below.

As a result, the first component, the second component, and the third component satisfying the relationship of E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) are combined to form a light emitting layer. Although the device lifetimes (LT50) of Examples 1-56 to 1-72 used are long, the relationship of E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh) It was confirmed that the element life (LT50) of Comparative Example 1-8 which was not satisfied was short.
Examples 1-56 to 1-72 have a half width in the range of 22 to 30 nm, an external quantum efficiency in the range of 12.0 to 16.8%, and an element lifetime (LT50) of 82 to 116 hours. Was within the range. Although all of them have good characteristics, the above Examples 1-27 to 1-55 showed even better characteristics. This means that the compound having the structure in which the formula (i) is multiplied as in the formula (ii) is used as the third compound, as compared with the case where the compound having the structure represented by the formula (i) is used as the third component. It shows that the characteristics are more excellent when used.

This tendency is attributed to the fact that the compounds of the third component used in Examples 1-27 to 1-72 are classified according to the structure of the basic skeleton, and the half width, external quantum efficiency, and device lifetime (LT50) are determined for each basic skeleton. It is also evident from FIG. 8 in which the data is averaged and graphed. In FIG. 8, the half width, the external quantum efficiency, and the element lifetime (LT50) are averaged for each compound having each basic skeleton of B2N2O2, B2N4, B2O2N2, BN2, BN2 / BNO, BN2 / BON, BONf, BOnN, BN2, and BON. The results of graphing are shown in order. B2N2O2, B2N4, B2O2N2, BN2, BN2 / BNO, BN2 / BON, BONf, BOnN, BN2, and BON representing the basic skeleton are included as part of the abbreviations of the compounds of the third component referred to in the present specification. Have been. FIG. 7 also shows the results of averaging the Tau (Delay) and Stokes shift of the compounds having each of these basic skeletons and forming a graph. 7 and 8, it can be seen that a device having a small Tau (Delay) has a longer device life (LT50), a smaller half width, and a higher external quantum efficiency. The compound represented by the formula (ii) has a smaller Tau (Delay) than the compound represented by the formula (i), and the characteristics of the organic electroluminescent device using the compound represented by the formula (ii) as the third component Is better. Among the compounds represented by the formula (ii), a compound having a basic skeleton of B2N4 is particularly preferable.

Based on the measurement results of Examples 1-27 to 1-55 using the compound represented by the formula (ii) having a small Tau (Delay) as the third component, the type and the half width of the substituent to be substituted on the basic skeleton were obtained. FIG. 10 is a graph showing the relationship between the external quantum efficiency and the device lifetime (LT50). FIG. 9 shows a graph of the average value of Tau (Delay) and Stokes shift for each substituent. 9 and 10, the graphs are divided into carbazolyl (Cz), diphenylamino (DPA), compounds substituted with both diphenylamino and fluorine atoms (DPA & F), phenyl (Ph), and tert-butyl (tBu). ing. Note that diphenylamino (DPA) and phenyl (Ph) include those substituted with alkyl. 9 and 10, the compound substituted with diphenylamino (DPA) has a small Tau (Delay) and Stokes shift, a long device lifetime (LT50), a small half width, and a low external quantum efficiency. Is also expensive. However, DPA & F substituted by a fluorine atom together with diphenylamino has a device life (LT50) that is not as long as when substituted by diphenylamino alone. As a substituent, diphenylamino (DPA) shows a particularly excellent effect in improving the device characteristics, and carbazolyl (Cz), phenyl (Ph), and tert-butyl (tBu) also show a good effect.

FIG. 11 shows the types of substituents substituted on the basic skeleton and the average of Stokes shift based on the measurement results of Examples 1-56 to 1-66 using the compound represented by formula (i) as the third component. 6 is a graph showing the relationship between the value and the average value of the half width. It was confirmed that the Stokes shift of the compound substituted with phenyl (Ph) was small and the half width was narrow. In particular, the effect of the phenyl group in which the ortho position was alkyl-substituted was excellent.

FIG. 7 shows that the compounds represented by the formula (i), BONf and BOnN, have a small Stokes shift. In both BONf and BOnN, ΔE (3, ST, Sh) is slightly larger than 0.3 eV, and therefore, Examples 1-67 to 1-72 using these compounds as the third component show E (1, T, Sh). Sh)> E (2, T, Sh)> E (3, T, Sh) and ΔE (3, ST, Sh)> ΔE (2, ST, Sh). The evaluation results of the Stokes shift of the third component and the device characteristics of Examples 1-67 to 1-72 are shown in the following table. The results in the table below show that the smaller the Stokes shift, the longer the device lifetime (LT50). From this, even when E (1, T, Sh)> E (2, T, Sh)> E (3, T, Sh), a compound having a small Stokes shift as the third component is used. It was shown that the element characteristics were improved when used.

4. Composition for forming light-emitting layer Next, in order to describe the present invention in more detail, specific examples of the composition for forming a light-emitting layer of the present invention and evaluation results thereof will be described. Not limited.

<Examples 2-1 to 2-32>
The first component, the second component, the third component, and the fourth component shown in the table below were mixed at a ratio shown in the table and stirred to prepare a composition for forming a light emitting layer. In the table, Tol used as the fourth component is toluene, DHNp is decahydronaphthalene, 3PxT is 3-phenoxytoluene, c6B is cyclohexylbenzene, Anis is anisole, Xyl is xylene (mixture), 1MNp is 1-methylnaphthalene, 8B is n-octylbenzene, DPE is diphenyl ether, and 4FAnis is 4-fluoroanisole.

について The following evaluations were performed for each of the prepared compositions for forming a light emitting layer.

(1) Evaluation of Solubility In order to evaluate the usefulness as an ink composition for inkjet application, turbidity and precipitation of each light emitting layer forming composition were confirmed and the solubility was evaluated. Those without turbidity and precipitation were rated "OK", and those with turbidity or precipitation were rated "NG".

(2) Evaluation of film forming property With respect to the composition for forming a light emitting layer which was “OK” in the evaluation of solubility, the film forming property of a film obtained after spin coating film formation or ink jet printing was evaluated by the following procedure. . After the film is formed, the film has a pinhole or a precipitate or unevenness is indicated by "x", and a pinhole or compound having no precipitation or unevenness is indicated by "O". (Ra <5 nm) are indicated by “◎”.

(Spin coating)
A UV-O ₃ treatment was performed by irradiating a clean glass substrate having a thickness of 0.5 mm and a size of 28 × 26 mm with irradiation energy of 1000 mJ / cm ² (low-pressure mercury lamp (254 nanometers)). Next, 0.3 to 0.6 mL of the ink composition was dropped on glass, and spin coating (slope, 5 seconds → 500 to 5000 rpm, 10 seconds → slope, 5 seconds) was performed. Further, it was dried on a hot plate at 120 ° C. for 10 minutes.

(Inkjet)
Using an inkjet, the ink was discharged into a pixel of 100 ppi and dried at 100 ° C.
The discharge stability of the inkjet was also evaluated immediately after the start of the inkjet discharge and after the continuous operation for 24 hours. A sample with poor ejection stability was rated "x", a sample with good ejection stability was rated "O", and a sample with extremely good ejection stability was rated "◎".

Evaluation results are as shown in the table below. In Examples 2-27, 2-31, 2-32 and 2-33, the viscosity and surface tension are also shown.

比較 Comparative Example 2-2 using compound R-BD2 having no boron atom as the third component was poor in solubility and could not be evaluated thereafter. In addition, even in the case of a compound having a boron atom, Comparative Example 2-1 using unsubstituted R-BD1 having a large molecular weight had poor solubility. On the other hand, Examples 2-1 to 2-33 using unsubstituted R-BD3 having a small molecular weight and a compound having a substituent even if having a large molecular weight are compounds having a boron atom, Both the film properties and the ink jet ejection stability were good.

5. Organic Electroluminescent Device Produced Using Composition for Forming Light-Emitting Layer Next, an organic electroluminescent device obtained by coating and forming an organic layer will be described. In forming the light emitting layer, a composition for forming a light emitting layer was used.

Synthesis of XLP-101 First, according to the method described in JP-A-2018-61028, XLP-101 as a polymer hole transport compound was synthesized by the following reaction. A copolymer in which M5 or M6 was bonded next to M4 was obtained, and the ratio of each unit was estimated to be 40:10:50 (molar ratio) based on the charging ratio. In the following formula, Bpin is pinacolate boryl.

PEDOT: PSS Solution A commercially available PEDOT: PSS solution (Clevios ™ PVP AI4083, aqueous dispersion of PEDOT: PSS, Heraeus Holdings) was used.

Preparation of OTPD Solution OTPD (LT-N159, manufactured by Luminescence Technology Corp.) and IK-2 (photocationic polymerization initiator, manufactured by San Apro) are dissolved in toluene, and the OTPD concentration is 0.7% by mass and the IK-2 concentration is 0. A 0.007% by mass OTPD solution was prepared.

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.

Preparation of PCz solution PCz (polyvinyl carbazole) was dissolved in dichlorobenzene to prepare a 0.7% by mass PCz solution.

<Example 3-1>
A PEDOT: PSS solution was spin-coated on a glass substrate on which ITO was deposited to a thickness of 150 nm, and baked on a hot plate at 200 ° C. for 1 hour to form a PEDOT: PSS film having a thickness of 40 nm. (Hole injection layer). Next, the OTPD solution is spin-coated, dried on a hot plate at 80 ° C. for 10 minutes, exposed to light at an exposure intensity of 100 mJ / cm ² with an exposure machine, and baked on a hot plate at 100 ° C. for 1 hour to obtain a solution. A OTPD film having a thickness of 30 nm, which was insoluble in the above, was formed (hole transport layer). Next, the composition for forming a light emitting layer prepared in Example 2-19 was spin-coated and baked on a hot plate at 120 ° C. for 1 hour to form a light emitting layer having a thickness of 20 nm.

The produced multilayer film was fixed to a substrate holder of a commercially available vapor deposition apparatus (manufactured by Showa Vacuum Co., Ltd.), and a molybdenum vapor deposition boat containing 2CzBN and BPy-TP2, a molybdenum vapor deposition boat containing LiF, and aluminum The inserted tungsten deposition boat was mounted. After the pressure in the vacuum chamber was reduced to 5 × 10 ⁻⁴ Pa, 2CzBN was heated and vapor-deposited to a thickness of 10 nm to form the electron transport layer 1. Next, BPy-TP2 was heated and vapor-deposited to a thickness of 20 nm to form an electron transport layer 2. The deposition rate at the time of forming the electron transport layer was 1 nm / sec. Thereafter, LiF was heated to be deposited at a deposition rate of 0.01 to 0.1 nm / sec so as to have a film thickness of 1 nm. Next, aluminum was heated and vapor-deposited to a thickness of 100 nm to form a cathode. Thus, an organic electroluminescent device was obtained.

<Example 3-2>
An organic electroluminescent device was obtained in the same manner as in Example 3-1. Note that the hole transport layer was formed by spin-coating an XLP-101 solution and baking it on a hot plate at 200 ° C. for 1 hour to form a film having a thickness of 30 nm.

<Example 3-3>
An organic electroluminescent device was manufactured in the same procedure as in Example 3-1 except that the composition for forming a light emitting layer prepared in Example 2-2 was used instead of the composition for forming a light emitting layer prepared in Example 2-19. Was prepared. Note that the hole transport layer was formed by spin-coating an XLP-101 solution and baking it on a hot plate at 200 ° C. for 1 hour to form a film having a thickness of 30 nm.

<Example 3-4>
An organic electroluminescent device was prepared in the same procedure as in Example 3-1 except that the composition for forming a light emitting layer prepared in Example 2-18 was used instead of the composition for forming a light emitting layer prepared in Example 2-19. Was prepared. Note that the hole transport layer was formed by spin-coating an XLP-101 solution and baking it on a hot plate at 200 ° C. for 1 hour to form a film having a thickness of 30 nm.

<Comparative Example 3-1>
An organic electroluminescent device was prepared in the same procedure as in Example 3-4, except that the composition for forming a light emitting layer prepared in Comparative Example 2-2 was used instead of the composition for forming a light emitting layer prepared in Example 2-18. Was prepared.

<Example 3-5>
An organic electroluminescent device was obtained in the same manner as in Example 3-1. The hole transport layer was formed by spin-coating a PCz solution and baking it on a hot plate at 120 ° C. for 1 hour to form a film having a thickness of 30 nm.

有機 It was confirmed that an organic electroluminescent device could be manufactured using the composition for forming a light emitting layer of the present invention. R-BD3, which is a compound containing boron, has excellent solubility, emits light in an organic electroluminescent device manufactured using a wet film formation method, has a blue peak wavelength, a small half-value width, The taste was excellent. Further, comparing Example 3-2 and Example 3-4, the device using the emitting dopant having a substituent was excellent in external quantum efficiency.

6. Composition containing polymer compound The composition for forming a light emitting layer of the present invention may contain a polymer compound or a crosslinkable compound. Further, the organic electroluminescent device of the present invention may contain a polymer compound or a crosslinkable compound.

<Example 4-1>
According to the method described in International Patent Publication No. WO2019 / 004248, a polymer containing a structure having a host as the first component and a boron atom as the third component can be synthesized.

The above polymer is a polymer containing the first component and the third component in the molecule. Addition of the heat-activated delayed phosphor as the second component is the composition for forming a light-emitting layer of the present invention.

<Example 4-2>
According to the method described in International Patent Publication No. WO2019 / 004248, it is possible to synthesize a polymer having the following structure of the host as the first component and the thermally activated delayed phosphor as the second component.

The above polymer is a polymer containing the first component and the second component in the molecule. When a compound having a boron atom as the third component is added, the composition for forming a light emitting layer of the present invention is obtained.

<Example 4-3>
According to the method described in International Patent Publication No. WO2019 / 004248, a polymer containing a structure having a host having the first component, a thermally activated delayed fluorescent material having the second component, and a boron atom being the third component is synthesized as follows. can do.

<Example 4-4>
According to the method described in International Patent Publication No. WO2019 / 004248, a polymer containing a structure having a host as the first component and a boron atom as the third component can be synthesized. Addition of the heat-activated delayed phosphor as the second component is the composition for forming a light-emitting layer of the present invention.

<Example 4-5>
According to the method described in International Patent Publication No. WO2019 / 004248, a polymer containing a structure having a host as the first component and a boron atom as the third component can be synthesized. Addition of the heat-activated delayed phosphor as the second component is the composition for forming a light-emitting layer of the present invention.

In addition, as the first component, the second component, or the third component added to the polymer, a single molecule that can be used as the first component, the second component, or the third component in the present invention can be used.

REFERENCE SIGNS LIST 100 Organic electroluminescent element 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

An organic electroluminescent device having a light emitting layer, wherein the light emitting layer is
As a first component, at least one host compound;
As a second component, at least one heat-activated delayed phosphor;
A compound having at least one type of boron atom as the third component,
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the first component is E (1, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component. The excited singlet energy level is E (2, S, Sh), and the excited singlet energy level determined from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the third component is E (3, S, Sh). When the following relational expression (1) is satisfied,
The first component may be included as a polymer compound having a structure in which two hydrogen atoms of the host compound are eliminated as a repeating unit,
The second component may be included as a polymer compound having a structure in which two hydrogen atoms of the thermally activated delayed fluorescent substance are eliminated as a repeating unit,
The third component may be included as a polymer compound having a structure in which two hydrogen atoms of the compound having a boron atom are eliminated as a repeating unit,
Organic electroluminescent device.
Relational expression (1): E (1, S, Sh) ≧ E (2, S, Sh) ≧ E (3, S, Sh)
As the third component, at least one of a compound represented by any of the following formulas (i), (ii) and (iii) and a multimeric compound having a plurality of structures represented by the following formula (i): The organic electroluminescent device according to claim 1, comprising:

(In the above formula (i),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y 1 is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X 1 and X 2 are each independently O, NR,> CR 2 , S or Se, wherein R of the NR and R of> CR 2 are an optionally substituted aryl, Is a heteroaryl, an optionally substituted cycloalkyl or an alkyl, and R of the NR is at least one selected from the above-mentioned ring A, ring B and ring C by a linking group or a single bond. May be combined, and
At least one hydrogen in the compound or structure represented by formula (i) may be replaced with cyano, halogen, or deuterium. )

(In the above formula (ii),
A ring, B ring, C ring and D ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y is B (boron),
X 1 , X 2 , X 3 and X 4 are each independently>O,>NR,> CR 2 ,> S or> Se, and R of> NR and> CR 2 R is an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted cycloalkyl or an optionally substituted alkyl, and R of the formula> NR represents a linking group. Or may be bonded to at least one selected from the A ring, B ring, C ring and D ring by a single bond,
R 1 and R 2 each independently represent hydrogen, alkyl having 1 to 6 carbons, cycloalkyl having 3 to 12 carbons, aryl having 6 to 12 carbons, heteroaryl or diarylamino having 2 to 15 carbons (Wherein aryl is aryl having 6 to 12 carbon atoms)
At least one hydrogen in the compound represented by the formula (ii) may be substituted with cyano, halogen, or deuterium. )

(In the above formula (iii),
A ring, B ring and C ring are each independently an aryl ring or a heteroaryl ring, and at least one hydrogen in these rings may be substituted;
Y 1 is B, P, P = O, P = S, Al, Ga, As, Si—R or Ge—R, wherein R of said Si—R and Ge—R is aryl or alkyl;
X 1 , X 2 and X 3 are each independently O, NR,> CR 2 , S or Se, and R of NR and R of> CR 2 may be substituted Aryl, optionally substituted heteroaryl, optionally substituted cycloalkyl or alkyl, and R of the NR is selected from the A ring, B ring and C ring by a linking group or a single bond. And may be associated with at least one of
At least one hydrogen in the compound or structure represented by formula (iii) may be substituted with cyano, halogen, or deuterium. )
The organic electroluminescent device according to claim 1, wherein the third component includes at least one compound represented by any of the following formulas (1), (2), (3), and (4).

(In the above formula (1),
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are each independently hydrogen, aryl, heteroaryl, diarylamino, diaryl Boryl, alkyl, cycloalkyl, alkoxy or aryloxy, which may be further substituted by aryl, heteroaryl or alkyl; and R 1 to R 3 , R 4 to R 7 and R 8 to R 11 May be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring is aryl, heteroaryl, diarylamino, alkyl, cyclo It may be substituted with at least one selected from alkyl, alkoxy and aryloxy, and these are further substituted with aryl. It may be substituted with at least one heteroaryl and alkyl,
X 1 and X 2 are each independently>O,> NR or> CR 2 , wherein R of> NR and R of> CR 2 are aryl, heteroaryl, cycloalkyl or alkyl. And these may be substituted with at least one selected from aryl, heteroaryl, cycloalkyl and alkyl;
However, X 1 and X 2 are not simultaneously> CR 2 ;
And
At least one hydrogen in the compounds and structures represented by formula (1) may be substituted with cyano, halogen or deuterium. )

(In the above formula (2),
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 and R 14 are each independently hydrogen, Aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio or alkyl-substituted silyl; One hydrogen may be substituted with aryl, heteroaryl or alkyl, and an adjacent group among R 5 to R 7 and R 10 to R 12 may be bonded to each other to form an aryl together with the b-ring or d-ring. May form a ring or a heteroaryl ring; At least one hydrogen is substituted with an aryl, heteroaryl, diarylamino, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio or alkyl-substituted silyl And at least one hydrogen therein may be substituted by aryl, heteroaryl or alkyl;
Y is B (boron),
X 1 , X 2 , X 3 and X 4 are each independently>O,> NR or> CR 2 , wherein R of> NR and R of> CR 2 have 6 carbon atoms. And aryls having up to 12 carbon atoms, heteroaryl having 2 to 15 carbon atoms, cycloalkyl having 3 to 12 carbon atoms or alkyl having 1 to 6 carbon atoms, and R of> NR and R of> CR 2 are —O—, —S—, —C (—R) 2 — or a single bond may be bonded to at least one selected from the a ring, b ring, c ring and d ring; R of —R) 2 — is hydrogen or alkyl having 1 to 6 carbons;
However, X 1 , X 2 , X 3 , and X 4 are not simultaneously> CR 2 ;
And
At least one hydrogen in the compound represented by the formula (2) may be substituted with cyano, halogen, or deuterium. )

(In the above formula (3),
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 9 , R 10 and R 11 are each independently hydrogen, aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl , Alkoxy or aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl, and alkyl, and further include R 1 to R 3 , R 4 to R 6, and R 9 to R Adjacent groups of 11 may be bonded to each other to form an aryl ring or a heteroaryl ring together with the a ring, b ring or c ring, and the formed ring is aryl, heteroaryl, diarylamino, alkyl, Optionally substituted with at least one selected from cycloalkyl, alkoxy and aryloxy; Further aryl, heteroaryl, it may be substituted with at least one selected from cycloalkyl and alkyl,
X 1 , X 2 and X 3 are each independently>O,> NR, or> CR 2 , wherein R of> NR and R of> CR 2 are aryl, heteroaryl, cycloaryl Alkyl or alkyl, which may be substituted with at least one selected from aryl, heteroaryl and alkyl;
However, X 1 , X 2 , and X 3 are not simultaneously> CR 2 .
And
At least one hydrogen in the compounds and structures represented by formula (3) may be substituted with cyano, halogen or deuterium. )

(In the above formula (4),
R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 and R 14 are each independently hydrogen, Aryl, heteroaryl, diarylamino, diarylboryl, alkyl, cycloalkyl, alkoxy or aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl; Adjacent groups among 1 to R 3 , R 4 to R 7 , R 8 to R 10 and R 11 to R 14 are bonded to each other to form an aryl ring or heteroaryl together with the a ring, b ring, c ring or d ring. May form a ring, wherein the formed ring is aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy and aryl. Optionally substituted with at least one selected from ruoxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl;
X is,> O, a> N-R or> CR 2, R and> of CR 2 R of the> N-R is aryl, heteroaryl or alkyl, select these aryl, heteroaryl and alkyl May be substituted with at least one of
L is a single bond,> CR 2 ,>O,> S or> NR, and R in the above> CR 2 and> NR is each independently hydrogen, aryl, heteroaryl, diarylamino , Alkyl, alkoxy or aryloxy, which may be further substituted with at least one selected from aryl, heteroaryl and alkyl;
However, X and L are simultaneously> not be a CR 2,
And
At least one hydrogen in the compounds and structures represented by formula (4) may be substituted with cyano, halogen or deuterium. )
As the third component, at least one compound represented by any of the formulas (1), (2) and (4) is included,
In the above formula (1), X 1 and X 2 are each independently> O or> NR,
In the formula (2), X 1 , X 2 , X 3 and X 4 are each independently> O or> NR,
In the above formula (4), X is> O and> NR, and L is a single bond.
The organic electroluminescent device according to claim 3.
As the third component, at least one compound represented by any of the formulas (1), (2), (3), and (4) is included, and an atom constituting a ring present in the compound includes: At least one selected from aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino, arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl The organic electroluminescent device according to claim 3, wherein the organic electroluminescent device is substituted with one.
As the third component, at least one compound represented by the formula (2) is contained, and the atoms constituting the ring present in the compound are aryl, heteroaryl, diarylamino, diarylboryl, diheteroarylamino , Arylheteroarylamino, alkyl, cycloalkyl, alkoxy, aryloxy, heteroaryloxy, arylthio, heteroarylthio and alkyl-substituted silyl, which are further substituted with aryl, heteroaryl, cycloalkyl The organic electroluminescent device according to claim 5, wherein the organic electroluminescent device may be substituted with at least one selected from and alkyl.
7. The organic electroluminescent device according to claim 1, wherein the third component has a partial structure represented by the following formula. However, each hydrogen in the partial structure may be independently substituted with aryl, heteroaryl, diarylamino, alkyl, cycloalkyl, alkoxy or aryloxy, and these are further substituted with aryl, heteroaryl, cycloalkyl and alkyl. And may be substituted with at least one selected from
The organic electroluminescent device according to any one of claims 3 to 6, wherein the compound represented by any of the formulas (1) to (4) includes any of the following partial structures.

(In the above partial structural formula,
Me represents methyl, tBu represents t-butyl, and a wavy line represents a bonding position.
However, hydrogen in the above partial structural formula is
Each independently may be substituted with aryl, heteroaryl, diarylamino, alkyl, alkoxy or aryloxy; the hydrogen in said aryl may be further substituted with aryl, heteroaryl or alkyl; May be further substituted with aryl, heteroaryl or alkyl, and the hydrogen in the diarylamino may be further substituted with aryl, heteroaryl or alkyl. )
The compound represented by any one of formulas (1) to (4), sp 3 carbon, sp 2 carbon atoms bound to m-position or p-position relative to the boron atom, or p-position relative to boron The organic electroluminescent device according to any one of claims 3 to 8, which has one of a nitrogen atom to be substituted.
The organic electroluminescent device according to claim 3, wherein the compound represented by the formula (2) is the following compound.
The organic electroluminescent device according to claim 4, wherein the compound represented by the formula (2) is the following compound.
12. The organic electroluminescent device according to claim 1, wherein the first component is a compound having, as a partial structure, at least one selected from carbazole and furan.
The organic electroluminescence according to any one of claims 1 to 12, wherein the first component contains at least one compound represented by any of the following formulas (H1), (H2), and (H3). element.

(In the above formulas (H1), (H2) and (H3), L 1 is arylene having 6 to 24 carbon atoms, heteroarylene, heteroarylenearylene or aryleneheteroarylenearylene,
At least one hydrogen in the compounds represented by each of the above formulas may be substituted with alkyl having 1 to 6 carbon atoms, cyano, halogen or deuterium. )
The second component is selected as a partial structure from carbazole, phenoxazine, acridine, triazine, pyrimidine, pyrazine, thioxanthene, benzonitrile, phthalonitrile, isophthalonitrile, diphenyl sulfone, triazole, oxadiazole, thiadiazole and benzophenone. The organic electroluminescent device according to any one of claims 1 to 13, comprising at least one of the following:
The organic electroluminescence according to any one of claims 1 to 14, wherein the second component contains at least one compound represented by any of the following formulas (AD1), (AD2), and (AD3). element.

(In the above formulas (AD1), (AD2) and (AD3),
M is each independently a single bond, —O—,> N—Ar or> CAr 2 ;
J is each independently an arylene having 6 to 18 carbon atoms, and the arylene is substituted with at least one selected from phenyl, alkyl having 1 to 6 carbons, and cycloalkyl having 3 to 12 carbons. May be
Q is each independently = C (-H)-or = N-;
Ar is each independently hydrogen, aryl having 6 to 18 carbons, heteroaryl having 6 to 18 carbons, alkyl having 1 to 6 carbons or cycloalkyl having 3 to 12 carbons, At least one hydrogen in the arylene may be substituted with phenyl, alkyl having 1 to 6 carbons or cycloalkyl having 3 to 12 carbons,
m is 1 or 2,
n is an integer of 2 to (6-m);
At least one hydrogen in the compounds represented by the above formulas may be substituted with halogen or deuterium. )
15. The organic electroluminescent device according to claim 1, wherein the second component contains at least one compound represented by the following formula (DAD1).
(D 1 -L 1 ) nA 1 (DAD1)
(In the above formula (DAD1), D 1 is a donor group, L 1 is a single bond or a conjugated linking group, A 1 is an acceptor group, n is 2 or more, and A 1 is substituted. Is an integer less than or equal to the maximum possible number.)
The organic electroluminescent device according to claim 16, wherein the second component contains at least one compound represented by the following formula (DAD2).
D 2 -L 2 -A 2 -L 3 -D 3 (DAD2)
(In the formula (DAD2), D 2 and D 3 each independently represent a donor group, L 2 and L 3 each independently represent a single bond or a conjugated linking group, and A 2 represents an acceptor group. Is.)
In the above formulas (AD1), (AD2) and (AD3),
M is each independently a single bond, —O— or>N—Ar;
J is each independently phenylene, and the phenylene may be substituted with alkyl having 1 to 4 carbon atoms;
Q is each independently = N-,
Ar is each independently hydrogen or phenyl, and the phenyl may be substituted with phenyl or alkyl having 1 to 4 carbons;
m is 1 or 2,
n is an integer of 4 to (6-m);
The organic electroluminescent device according to claim 17.
19. The organic electroluminescent device according to claim 1, wherein the inverse crossing speed of the second component is 10 5 s −1 or more.
20. The organic electroluminescent device according to claim 1, wherein the delayed fluorescence lifetime of the third component is 0.05 μsec to 40 μsec.
20. The organic electroluminescence device according to claim 1, wherein the delayed fluorescence lifetime of the third component is 0.05 μsec to 20 μsec.
22. The organic electroluminescent device according to claim 1, wherein the Stokes shift obtained from the difference between the peak top of the fluorescence spectrum and the peak top of the absorption spectrum of the third component is 14 nm or less.
22. The organic electroluminescent device according to claim 1, wherein a Stokes shift obtained from a difference between a peak top of a fluorescence spectrum and a peak top of an absorption spectrum of the third component is 10 nm or less.
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), and the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). When the excited triplet energy level obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the third component is E (3, T, Sh), the singlet triplet energy difference (ΔE (2, The organic electroluminescent device according to any one of claims 1 to 23, wherein ST, Sh) and ΔE (3, ST, Sh)) have the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.50 eV
ΔE (3, ST, Sh) = E (3, S, Sh) −E (3, T, Sh) ≦ 0.20 eV
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), and the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). When the excited triplet energy level obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the third component is E (3, T, Sh), the singlet triplet energy difference (ΔE (2, The organic electroluminescent device according to any one of claims 1 to 24, wherein ST, Sh) and ΔE (3, ST, Sh)) have the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh)
ΔE (3, ST, Sh) = E (3, S, Sh) -E (3, T, Sh)
ΔE (2, ST, Sh) ≧ ΔE (3, ST, Sh)
26. The organic electroluminescent device according to claim 1, wherein a singlet / triplet energy difference (ΔE (2, ST, Sh)) of the second component has the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.30 eV
27. The organic electroluminescent device according to claim 1, wherein the singlet / triplet energy difference (ΔE (2, ST, Sh)) of the second component has the following relationship.
ΔE (2, ST, Sh) = E (2, S, Sh) −E (2, T, Sh) ≦ 0.15 eV
The excitation singlet energy level obtained from the shoulder on the short wavelength side of the peak of the fluorescence spectrum of the second component is E (2, S, Sh), and the excitation singlet energy level is obtained from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the second component. The excited triplet energy level is E (2, T, Sh), and the excited singlet energy level determined from the shoulder on the peak short wavelength side of the fluorescence spectrum of the third component is E (3, S, Sh). 28. Any one of claims 1 to 27, wherein when the excited triplet energy level determined from the shoulder on the short wavelength side of the peak of the phosphorescence spectrum of the third component is E (3, T, Sh), these have the following relationship. The organic electroluminescent device according to claim 1.
E (2, S, Sh) ≧ E (3, S, Sh)
E (2, T, Sh) ≦ E (3, T, Sh)
The organic electroluminescent device according to any one of claims 1 to 28, wherein the Stokes shift obtained from the difference between the peak top of the fluorescence spectrum and the peak top of the absorption spectrum of the third component is 10 nm or less.
The organic compound according to any one of claims 1 to 29, wherein the third component is contained as a polymer compound having a repeating unit of a group from which two hydrogen atoms have been eliminated from the compound having a boron atom. Electroluminescent device.
31. The polymer compound having, as a repeating unit, a group from which two hydrogen atoms have been eliminated from the compound having a boron atom, the polymer compound also having, as a repeating unit, a group from which two hydrogen atoms have been eliminated from the host compound. Organic electroluminescent device.
31. The polymer compound having, as a repeating unit, a group from which two hydrogen atoms have been eliminated from the compound having a boron atom, wherein the polymer from which two hydrogen atoms have been eliminated from the delayed fluorescent substance also has a repeating unit. 32. The organic electroluminescent device according to 31.
A display device comprising the organic electroluminescent device according to any one of claims 1 to 32.
A lighting device comprising the organic electroluminescent device according to any one of claims 1 to 32.
A composition for forming a light-emitting layer for coating and forming a light-emitting layer of an organic electroluminescent device,
A composition for forming a light-emitting layer, comprising at least one organic solvent as a fourth component in addition to the first component, the second component, and the third component according to any one of claims 1 to 32 (provided that the composition is the same as that of the first or second embodiment). And the third component is not the following compound.)
36. The composition according to claim 35, wherein the at least one organic solvent in the fourth component has a boiling point of 130 ° C. to 350 ° C.
The fourth component contains a good solvent (GS) and a poor solvent (PS) for at least one of the first component, the second component, and the compound that is the third component, and the good solvent (GS) 37. The composition for forming a light-emitting layer according to claim 35 or 36, wherein a boiling point (BP GS ) of the poor solvent (PS) is lower than a boiling point (BP PS ) of the poor solvent (PS).
The first component is 0.0998% by mass to 4.0% by mass with respect to the total mass of the composition for forming a light emitting layer;
0.0001% by mass to 2.0% by mass of the second component based on the total mass of the composition for forming a light emitting layer;
The third component is 0.0001% by mass to 2.0% by mass based on the total mass of the composition for forming a light emitting layer;
90.0% by mass to 99.9% by mass of the fourth component, based on the total mass of the composition for forming a light emitting layer;
The composition for forming a light emitting layer according to any one of claims 35 to 37.
An organic electroluminescent device having a light emitting layer formed by using the light emitting layer forming composition according to any one of claims 35 to 38.
A compound in which at least one hydrogen of the compound represented by the formula (ii) according to claim 2 is replaced by the following partial structure (B), chlorine, bromine, or iodine.

(In the above partial structure (B), R 40 and R 41 are alkyl having a total of 2 to 10 carbon atoms which may be bonded, and the wavy line is a bonding site to another structure.)
A repeating unit containing a structure in which two hydrogen atoms are eliminated from a compound having a boron atom, a repeating unit containing a structure in which two hydrogen atoms are eliminated from a thermally activated delayed fluorescent substance, and two hydrogen atoms from a host compound A polymer compound comprising at least two kinds of repeating units selected from repeating units having a structure from which is eliminated.
At least one kind of a repeating unit containing a structure in which two hydrogen atoms are eliminated from a compound having a boron atom, at least one kind of a repeating unit containing a structure in which two hydrogen atoms are eliminated from a thermally activated delayed fluorescent substance, And a polymer compound containing at least one repeating unit having a structure in which two hydrogen atoms are eliminated from a host compound.