WO2024048690A1

WO2024048690A1 - Material for light emitting layers, organic electroluminescent element, organic el display device, organic el lighting, composition, and method for producing organic electroluminescent element

Info

Publication number: WO2024048690A1
Application number: PCT/JP2023/031648
Authority: WO
Inventors: 和弘長山; 一毅岡部; 司長谷川; 奈良麻優子上田; 宏一朗飯田
Original assignee: 三菱ケミカル株式会社
Priority date: 2022-08-31
Filing date: 2023-08-30
Publication date: 2024-03-07

Abstract

The present invention addresses the problem of providing an organic electroluminescent element which has a long service life. The present invention relates to a material for light emitting layers of organic electroluminescent elements, the material containing a light emitting compound and an organometallic compound. With respect to this material for light emitting layers, the organometallic compound has a molecular weight of 1,200 or more; the light emitting compound is a specific compound; and relational expression (E-1) is satisfied.　Formula (E-1): T1A ≥ T1B (In formula (E-1), T1A represents the triplet energy level (eV) of the organometallic compound; and T1B represents the triplet energy level (eV) of the light emitting compound.)

Description

Material for light-emitting layer, organic electroluminescent device, organic EL display device, organic EL lighting, composition, and method for manufacturing organic electroluminescent device

The present invention relates to a material for a light emitting layer, an organic electroluminescent device, an organic EL display device, an organic EL lighting, a composition, and a method for manufacturing an organic electroluminescent device.

In recent years, as thin film type electroluminescent elements, organic electroluminescent elements using organic thin films have been developed instead of those using inorganic materials. Organic electroluminescent devices (OLEDs) usually have a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, etc. between an anode and a cathode, and materials suitable for each layer are being developed. There are also red, green, and blue light emitting colors, which are all under development.

Further, examples of methods for forming the organic layer of the organic electroluminescent device include vacuum evaporation method and wet film formation method (coating method). The vacuum evaporation method has the advantage that since it is easy to stack layers, charge injection from the anode and/or cathode can be improved and excitons can be easily confined in the light emitting layer. On the other hand, the wet film formation method does not require a vacuum process and can easily be applied to a large area.By using a coating solution that is a mixture of multiple materials with various functions, it is possible to easily create multiple materials with various functions. It has advantages such as being able to form a layer containing the following materials. Therefore, in recent years, research and development of organic electroluminescent devices using coating methods has been actively conducted.

For example, Patent Documents 1 to 3 disclose organic electroluminescent elements having a hole injection layer containing polystyrene sulfonic acid and a light emitting layer containing a light emitting material having a polycyclic heterocyclic compound skeleton containing boron and nitrogen. Are listed.
Further, research and development is being conducted to utilize the triplet excited state, which accounts for 75% of the excitons generated in organic electroluminescent devices. For example, in Non-Patent Documents 1 and 2, as a means to increase the luminous efficiency of an organic electroluminescent device, in addition to a luminescent material having a polycyclic heterocyclic compound skeleton, a luminescent material having a polycyclic heterocyclic compound skeleton is used in a luminescent layer formed by a vacuum evaporation method. It has been reported that an organometallic compound containing iridium, which is a phosphorescent material, as a central metal is included as a material to assist in this.

International Publication No. 2016/152418 International Publication No. 2019/198699 International Publication No. 2019/235452

In general, polycyclic heterocyclic compounds containing boron have an empty p orbital on the boron and are likely to react with various reactive groups. Therefore, with the techniques disclosed in Patent Documents 1 to 3, the driving voltage of the organic electroluminescent element cannot be sufficiently reduced, and the driving life cannot be improved. The techniques disclosed in Patent Documents 1 to 3 use a hole injection layer containing strongly acidic polystyrene sulfonic acid, so that water and sulfonic acid groups taken in during formation of the hole injection layer are This is thought to be caused by a reaction with the ring heterocyclic compound during device operation. Furthermore, in the technique disclosed in Non-Patent Document 1, it is necessary to keep the deposition rate ratio of three or more materials constant when the host material is included, making it difficult to obtain stable performance.

The present invention has been made in view of the above-mentioned conventional situation, and an object to be solved is to provide an organic electroluminescent element with a long driving life.

As a result of intensive studies, the present inventors have found that the organic metal compound contains a light-emitting compound and an organometallic compound, the molecular weight of the organometallic compound is within a specific range, and the triplet energy level of the organometallic compound is the triplet energy level of the light-emitting compound. The inventors have discovered that the above problems can be solved by using a light-emitting layer in which the singlet energy level and triplet energy level of the light-emitting compound have a specific relationship, and have completed the present invention. .

That is, the gist of the present invention is as follows.

Aspect 1 of the present invention is
A material for a light-emitting layer of an organic electroluminescent device containing a light-emitting compound and an organometallic compound,
The organometallic compound has a molecular weight of 1,200 or more,
The luminescent compound is a compound represented by the following formula (1),
This is a material for a light-emitting layer that satisfies the following relational expression (E-1).
T1A≧T1B Formula (E-1)
(In formula (E-1),
T1A: Triplet energy level (eV) of the organometallic compound
T1B: triplet energy level (eV) of the light-emitting compound
represents. )

[In formula (1), ring Cy ¹ , ring Cy ² , ring Cy ³ and ring Cy ⁴ each independently represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle.
Ring Cy ¹ , Cy ² , Cy ³ and Cy ⁴ may further have a fused ring.
R represents a hydrogen atom or a substituent,
x, y, z, and w each represent the maximum number of bonds that R can bond to ring Cy ¹ , ring Cy ² , ring Cy ³ , and ring Cy ⁴ .
Q ¹¹ , Q ¹² , Q ²¹ and Q ²² represent NR, O or S.
When multiple R's exist, they may be the same or different.
When R is a substituent, adjacent R may be combined with each other or with ring Cy ¹ , ring Cy ² , ring Cy ³ and ring Cy ⁴ adjacent to R to form a ring. ]

Aspect 2 of the present invention is the light-emitting layer material of Aspect 1, comprising:
The organometallic compound is a light-emitting layer material represented by the following formula (201).

[Ring A201 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ring A202 represents an aromatic heterocyclic structure which may have a substituent.
R ²⁰¹ and R ²⁰² each independently have a structure represented by the above formula (202).
When a plurality of R ²⁰¹ and R ²⁰² exist, they may be the same or different.
Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon ring structure that may have a substituent or an aromatic heterocyclic structure that may have a substituent.
Ar ²⁰² is an aromatic hydrocarbon ring structure that may have a substituent, an aromatic heterocyclic structure that may have a substituent, or an aliphatic hydrocarbon structure that may have a substituent. represents.
When a plurality of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ exist, they may be the same or different.
* represents bonding to ring A201 or ring A202.
B ²⁰¹ -L ²⁰⁰ -B ²⁰² represents an anionic bidentate ligand. B ²⁰¹ and B ²⁰² each independently represent a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring, in which case B ²⁰¹ and/or B ²⁰² have a ring structure. represents.
L ²⁰⁰ represents a single bond or an atomic group that constitutes a bidentate ligand together with B ²⁰¹ and B ²⁰² .
When a plurality of B ²⁰¹ -L ²⁰⁰ -B ²⁰² exist, they may be the same or different.
i1 and i2 each independently represent an integer from 0 to 12.
i3 is an integer of 0 or more with an upper limit of the number that can be replaced by Ar ²⁰² .
j is an integer of 0 or more with an upper limit of the number that can be replaced by Ar ²⁰¹ .
k1 and k2 are each independently an integer of 0 or more, with the upper limit being the number that can be substituted into ring A201 and ring A202.
m is an integer from 1 to 3. ]

Aspect 3 of the present invention is the light-emitting layer material according to aspect 1 or 2,
The light-emitting layer material has T1A of 2.10 eV or more and 2.80 eV or less.

Aspect 4 of the present invention is the light-emitting layer material according to any one of aspects 1 to 3,
The light-emitting compound represented by the formula (1) is a light-emitting layer material represented by the formula (2-1) or the formula (2-2).

[In formula (2-1) and formula (2-2), Q ³¹ and Q ³² represent O or S.
R is the same as in formula (1) above, and when a plurality of R's exist, they are independent from each other and may be the same or different.
When R is a substituent, it may combine with adjacent R's to form a ring. ]

Aspect 5 of the present invention is the light-emitting layer material according to any one of aspects 1 to 4,
The light-emitting compound represented by the formula (1) is a light-emitting layer material represented by the formula (2-3).

[In formula (2-3), Q ³¹ and Q ³² represent O or S.
R is the same as in formula (1) above, and when a plurality of R's exist, they are independent from each other and may be the same or different.
When R is a substituent, it may combine with adjacent R's to form a ring.
R' represents a hydrogen atom or a substituent, and when multiple R's exist, they are independent from each other and may be the same or different. ]

Aspect 6 of the present invention provides the light-emitting layer material according to any one of aspects 1 to 5,
The light-emitting layer material has a ratio of MwA/MwB of 2.0 or more, where MwA is the molecular weight of the organometallic compound and MwB is the molecular weight of the light-emitting compound.

Aspect 7 of the present invention provides the light-emitting layer material according to any one of aspects 1 to 6,
The light-emitting layer material further includes a host material.

Aspect 8 of the present invention is the light-emitting layer material of aspect 7,
A light-emitting layer in which the host material contains at least one selected from a compound represented by the following formula (250), a compound represented by the following formula (240), and a compound represented by the following formula (260). It is a material for use.

(In formula (250),
each W independently represents CH or N, at least one W is N,
Xa ¹ , Ya ¹ and Za ¹ each independently represent a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a carbon atom which may have a substituent. represents a divalent aromatic heterocyclic group of number 3 to 30,
Xa ² , Ya ² and Za ² are each independently a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. Represents a monovalent aromatic heterocyclic group having 3 to 30 carbon atoms,
g11, h11, and j11 each independently represent an integer from 0 to 6,
At least one of g11, h11, and j11 is an integer of 1 or more,
When g11 is 2 or more, multiple Xa ^1s may be the same or different,
When h11 is 2 or more, multiple Ya ^1s may be the same or different,
When g11 is 2 or more, multiple Za ^1s may be the same or different,
R ³¹ represents a hydrogen atom or a substituent, and the four R ^31s may be the same or different,
However, when g11, h11, or j11 is 0, the corresponding Xa ² , Ya ² , and Za ² are not hydrogen atoms. )

(In formula (240),
Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
R ⁶¹¹ and R ⁶¹² are each independently a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
n ⁶¹¹ and n ⁶¹² are each independently an integer of 0 to 4. )

(In formula (260),
Ar ⁶¹ to Ar ⁶⁵ are each independently a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms which may have a substituent,
L ¹ to L ⁵ are each independently a divalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms that may have a substituent,
R ⁶⁰ each independently represents a substituent,
m1 to m5 each independently represent an integer from 0 to 5,
n represents an integer from 0 to 10,
a1 to a3 each independently represent an integer from 0 to 3,
However, at least one group among Ar ⁶¹ , Ar ⁶² , Ar ⁶³ , Ar ⁶⁴ , and at least one Ar ⁶⁵ when n is 1 or more does not become a hydrogen atom. )

Aspect 9 of the present invention is the light-emitting layer material of aspect 8,
The host material is a light-emitting layer material containing at least a compound represented by the formula (250).

Aspect 10 of the present invention is the light-emitting layer material according to aspect 8 or 9,
In the formula (250), -(Ya ¹ ) _h11 -(Ya ² ) and -(Za ¹ ) _j11 -(Za ² ) are not unsubstituted phenyl groups at the same time, which is a material for a light-emitting layer.

Aspect 11 of the present invention is the light-emitting layer material according to any one of aspects 8 to 10,
In the formula (250), a substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms may have, and a substituent that the aromatic heterocyclic group having 3 to 30 carbon atoms may have; The group is selected from the following substituent group Z2, and the substituent selected from the following substituent group Z2 has no further substituents, and is a material for a light emitting layer.

<Substituent group Z2>
Alkyl group, alkoxy group, aryloxy group, heteroaryloxy group, alkoxycarbonyl group, dialkylamino group, diarylamino group, arylalkylamino group, acyl group, halogen atom, haloalkyl group, alkylthio group, arylthio group, silyl group, Siloxy group, cyano group, aromatic hydrocarbon group, and aromatic heterocyclic group

Aspect 12 of the present invention is the light-emitting layer material according to any one of aspects 8 to 11,
This is a material for a light emitting layer, in which at least two of the Ws in the formula (250) are N.

Aspect 13 of the present invention is a light-emitting layer material according to any one of aspects 8 to 12, comprising:
In the above formula (250), (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) h11 when _h11 is 1 or more, (Za ¹ ) j11 when _j11 is 1 or more, the above Ar ⁶¹¹ and Ar ⁶¹² in formula (240), (L ¹ ) _m1 when m1 is 1 or more, (L ² ) _m2 when m2 is 1 or more, and m3 in formula (260) above (L ³ ) _m3 in the above case, (L ⁴ ) _m4 in the case where m4 is 1 or more, and (L ⁵ ) m5 in the case where n is 1 or more and _m5 is 1 or more are each independently expressed by the following formula (11 ) to a material for a light-emitting layer having a partial structure selected from partial structures represented by the following formula (17).

(In each of formulas (11) to (17), * indicates the bonding position with the adjacent structure, or in the case of formula (250), the corresponding position when Xa ² , Ya ² , or Za ² is a hydrogen atom. In the case of formula (260), a hydrogen atom represents a hydrogen atom when Ar ⁶¹ , Ar ⁶² , Ar ⁶³ , Ar ⁶⁴ or Ar ⁶⁵ is a hydrogen atom, and at least one of the two * is adjacent (Represents the bonding position with the structure.)

Aspect 14 of the present invention is the light-emitting layer material according to any one of aspects 8 to 13,
In the formula (250), at least one of -(Xa ¹ ) _g11 -(Xa ² ), -(Ya ¹ ) _h11 -(Ya ² ), and -(Za ¹ ) _j11 -(Za ² ) is as follows: It is a material for a light-emitting layer having any one of a partial structure or a terminal structure represented by the formula (250-1) to the following formula (250-10).

[In formulas (250-1) to (250-10), * represents the bonding position. Ar ²⁵⁰ represents an aromatic hydrocarbon group having 6 to 20 carbon atoms. R ³² represents a substituent, and the structures represented by formulas (250-1) to (250-10) may further have a substituent. ]

Aspect 15 of the present invention is the light-emitting layer material according to any one of aspects 8 to 14,
The host material is a light-emitting layer material containing at least a compound represented by the formula (240).

Aspect 16 of the present invention is the light-emitting layer material according to any one of aspects 8 to 15,
In the compound represented by the formula (240), the Ar ⁶¹¹ and the Ar ⁶¹² each independently have a partial structure selected from the following formulas (11) to (17) and (21) to (24), It is a material for a light emitting layer.

(* represents a bonding position with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position with an adjacent structure)

Aspect 17 of the present invention is the light-emitting layer material according to any one of aspects 8 to 16,
The host material is a light-emitting layer material containing at least a compound represented by the formula (260).

Aspect 18 of the present invention is the light-emitting layer material according to any one of aspects 8 to 17,
For a light emitting layer, one or more and three or less groups of Ar ⁶¹ , Ar ⁶² and at least one Ar ⁶⁵ in the formula (260) are the following formula (261) or the following formula (262) It is the material.

(In formula (261) or formula (262),
The asterisk (*) represents the bonding position with formula (260),
R ¹⁰¹ to R ¹²⁶ each independently represent a hydrogen atom or a substituent. )

Aspect 19 of the present invention is the light-emitting layer material according to any one of aspects 8 to 18,
The compound represented by the above formula (250) was defined as (group A), the compound represented by the above formula (240) was defined as (group B), and the compound represented by the above formula (260) was defined as (group C). When, the host material is selected from at least one kind from each of at least two arbitrary groups among the three groups represented by the above (group A), the above (group B), and the above (group C). A light-emitting layer material containing at least two types of compounds.

Aspect 20 of the present invention is
An organic electroluminescent device having an anode, a cathode, and a light emitting layer,
the light emitting layer is provided between the anode and the cathode,
The present invention is an organic electroluminescent device, wherein the light emitting layer contains the light emitting layer material according to any one of aspects 1 to 19.

Aspect 21 of the present invention is
This is an organic EL display device or an organic EL lighting including the organic electroluminescent element of Aspect 20.

Aspect 22 of the present invention is
A composition comprising the light-emitting layer material according to any one of aspects 1 to 19 and an organic solvent.

Aspect 23 of the present invention is:
A method for manufacturing an organic electroluminescent device having an anode, a light emitting layer, and a cathode in this order on a substrate, the method comprising:
A method for producing an organic electroluminescent device, comprising a step of forming the light emitting layer by a wet film forming method using the composition of Aspect 22.

The organic electroluminescent device of the present invention exhibits excellent device characteristics and particularly has a long operating life.

FIG. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent device of the present invention.

Below, a material for a light-emitting layer of an organic electroluminescent device, which is an embodiment of the present invention, an organic electroluminescent device, an organic EL display device including the organic electroluminescent device, an organic EL lighting device including the organic electroluminescent device, and a composition. Embodiments of the product and the method for manufacturing an organic electroluminescent device using the composition will be described in detail.

[Material for organic electroluminescent device]
<Materials according to the first embodiment>
The light-emitting layer material according to the first embodiment of the present invention is
A material for a light-emitting layer of an organic electroluminescent device containing a light-emitting compound and an organometallic compound,
The organometallic compound has a molecular weight of 1,200 or more,
The luminescent compound is a compound represented by the following formula (1),
The material satisfies the following relational expression (E-1).
T1A≧T1B Formula (E-1)
(In formula (E-1),
T1A: Triplet energy level (eV) of the organometallic compound
T1B: triplet energy level (eV) of the light-emitting compound
represents. )

<Materials according to the second embodiment>
The material according to the second embodiment of the present invention is
A material for a light-emitting layer of an organic electroluminescent device, comprising a light-emitting compound, an organometallic compound, and a host material,
The luminescent compound is a compound represented by the following formula (1),
The organometallic compound is a compound represented by formula (201) described below,
The host material contains at least one selected from a compound represented by formula (250) described below, a compound represented by formula (240) described below, and a compound represented by formula (260) described below. It is an organic electroluminescent device,
The material satisfies the following relational expression (E-1).
T1A≧T1B Formula (E-1)
(In formula (E-1),
T1A: Triplet energy level (eV) of the organometallic compound
T1B: Triplet energy level (eV) of the polycyclic heterocyclic compound
represents. )

[Organic electroluminescent device]
An organic electroluminescent device according to another embodiment of the present invention is
An organic electroluminescent device having an anode, a cathode, and a light emitting layer,
the light emitting layer is provided between the anode and the cathode,
The organic electroluminescent device is an organic electroluminescent device in which the light-emitting layer includes the light-emitting layer material.

The reason why the organic electroluminescent device containing the luminescent layer material according to the first embodiment of the present invention in its luminescent layer has a long driving life is presumed as follows.
The organic electroluminescent device of the present invention has an organometallic compound and a luminescent compound in the luminescent layer. Among these, the organometallic compound plays the role of efficiently transferring the energy of the excited state generated in the light emitting layer to the light emitting compound.
When excitation energy is transferred from an organometallic compound object to a light-emitting compound, if the molecular weight of the organometallic compound is small, the interaction between the organometallic compounds cannot be ignored, and the energy transferred to the light-emitting compound is lost, resulting in a high Performance cannot be obtained. The molecular weight of the organometallic compound is greater than a certain level, and the triplet energy level and singlet energy level of the organometallic compound and the light-emitting compound have a specific relationship, so that the interaction between the organometallic compounds can be improved. It is thought that the effect can be suppressed to an appropriate degree and exhibits high performance.
It is thought that triplet excitation energy in the light-emitting layer can be smoothly transferred to the light-emitting compound by having the molecular weight of the organometallic compound above a certain level and suppressing interactions between the organometallic compounds. It is thought that by directly transferring triplet excitation energy to a light-emitting compound, the light-emitting compound is less likely to become unstable, and a device with a long life can be obtained.

In the following description, one example (representative example) of the embodiment of the present invention will be described as an organic electroluminescent element containing the light-emitting layer material of the present invention in the light-emitting layer, but the present invention does not exceed the gist thereof. Not specific to these contents.

<Light-emitting layer>
The light-emitting layer of the organic electroluminescent device of the present invention contains a light-emitting compound represented by the above formula (1) and an organometallic compound,
The organometallic compound has a molecular weight of 1,200 or more,
It is a light-emitting layer that satisfies the following relational expression (E-1).
T1A≧T1B Formula (E-1)
(In formula (E-1),
T1A: Triplet energy level (eV) of the organometallic compound
T1B: triplet energy level (eV) of the light-emitting compound
represents. )

In the present invention, by satisfying the above formula (E-1), the organometallic compound efficiently transfers the energy of the excited triplet generated in the light emitting layer to the light emitting compound, and the light emitting compound emits light with high efficiency. .

Further, it is preferable that the light-emitting compound in the present invention satisfies the following relational formula (E-2).
ΔEST=S1B-T1B≦0.30eV Formula (E-2)
(S1B: Singlet energy level (eV) of the light emitting compound)
By satisfying the above formula (E-2), the excited triplet energy of the light-emitting compound is efficiently internally converted into an excited singlet, and the light-emitting compound emits light with high efficiency.
ΔEST in formula (E-2) is 0.30 eV or less, preferably 0.25 eV or less, and more preferably 0.20 eV or less. There is no particular limit to the lower limit of ΔEST, but it is usually 0.01 eV or more.

T1A is preferably 1.90 eV or more, more preferably 2.00 eV or more, even more preferably 2.10 eV or more, and preferably 3.00 eV or less, more preferably 2.80 eV or less, even more preferably 2.70 eV or less. It is. By setting T1A in this range, the excited state of the organometallic compound is not too high in energy, which suppresses the decomposition of the organometallic compound, and the energy is not too low, so that the excited state of the organometallic compound quickly converts into a light-emitting compound. Therefore, it is thought that a device with higher performance can be obtained.
Note that the above T1A, T1B, and S1B can be determined by the following method.
S1B, T1A and T1B can be determined from the peak wavelengths of the fluorescence spectrum and phosphorescence spectrum, respectively. The fluorescence spectrum and phosphorescence spectrum can be measured using a spectrophotometer, for example, using a spectrofluorometer F-7000 manufactured by Hitachi High-Tech Science. When making measurements, a solution prepared by dissolving a compound in an appropriate organic solvent at a concentration of about 10 ^-6 to 10 ^-5 M is used as a sample. Fluorescence spectra are measured at room temperature. Phosphorescence is measured by cooling to 77K with liquid nitrogen.

Further, it is preferable that the light-emitting compound in the present invention satisfies the following relational formula (E-3).
PkA<PkB Formula (E-3)
(In formula (E-3),
PkA: Maximum emission wavelength (nm) of the organometallic compound
PkB: Maximum emission wavelength (nm) of the luminescent compound
represents. )

In the present invention, by satisfying the above formula (E-3), the organometallic compound efficiently transfers the excitation energy generated in the light emitting layer to the light emitting compound, and the light emitting compound emits light with high efficiency.

PkA is preferably 550 nm or more and 650 nm or less, the lower limit is more preferably 560 nm or more, more preferably 570 nm or more, and the upper limit is still more preferably 630 nm or less, more preferably 610 nm or less. PkB may satisfy the above formula (E-3), but preferably the difference between PkB and PkA is usually 80 nm or less, preferably 50 nm or less, more preferably 40 nm or less, more preferably 30 nm or less, particularly preferably 25 nm. It is as follows. When PkA and PkB are within this range, the excitation energy of the organometallic compound is efficiently transferred to the light-emitting compound, resulting in a higher performance element. In addition, since the molecular weight of the organometallic compound is 1,200 or more, the light-emitting compound of the present invention having the relationship of formula (E-3) efficiently emits light at long wavelengths, particularly in the red light emission region, and has higher performance. It is thought that an element can be obtained.

(Maximum emission wavelength)
PkA and PkB are measured by the following method.
At room temperature, a solution of the organometallic compound or luminescent compound of the present invention dissolved in an organic solvent at a concentration of 1×10 ⁻⁴ mol/L or less was prepared, and the organic EL quantum yield measurement was performed using a spectrophotometer (manufactured by Hamamatsu Photonics Co., Ltd.). The emission spectrum of the solution is measured using apparatus C9920-02). The wavelength showing the maximum value of the obtained emission spectrum intensity is defined as the maximum emission wavelength in the present invention. As the organic solvent for dissolving the organometallic compound and the luminescent compound, toluene, 2-methyltetrahydrofuran, etc. are preferably used, and toluene is usually preferred.

<Light-emitting compound>

<Polycyclic heterocyclic compound>
The light-emitting compound in the present invention is a polycyclic heterocyclic compound represented by the following formula (1).

[In formula (1), ring Cy ¹ , ring Cy ² , ring Cy ³ and ring Cy ⁴ each independently represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle.
Ring Cy ¹ , Cy ² , Cy ³ and Cy ⁴ may further have a fused ring.
R represents a hydrogen atom or a substituent,
x, y, z, and w each represent the maximum number of bonds that R can bond to ring Cy ¹ , ring Cy ² , ring Cy ³ , and ring Cy ⁴ .
Q ¹¹ , Q ¹² , Q ²¹ and Q ²² represent NR, O or S.
When multiple R's exist, they may be the same or different.
When R is a substituent, it may be bonded to adjacent R's or to ring Cy ¹ , Cy ² , Cy ³ and Cy ⁴ adjacent to R to form a ring. ]

<Preferred light-emitting compound>
The light-emitting compound represented by formula (1) is preferably a compound represented by formula (2-1) or formula (2-2).

The luminescent compound represented by formula (1) is more preferably a compound represented by formula (2-3).

In the light-emitting compounds represented by the above formula (1), the above formula (2-1), the above formula (2-2), and the above formula (2-3), the above R is a hydrogen atom or the following [substituent group W1 ] It is more preferable that it is a substituent selected from. In the light-emitting compound represented by the formula (2-3), it is more preferable that the R' is selected from the following [R'].

[R]
R is a hydrogen atom or a substituent, and when R is a substituent, it is an arbitrary substituent, but preferably a substituent selected from the following [substituent group W1].
[Substituent group W1]
D, F, Cl, Br, I, -N(R') ₂ , -CN, -NO ₂ , -OH, -COOR', -C(=O)R', -C(=O)NR', -P(=O)(R') ₂ , -S(=O)R', -S(=O) ₂ R', -OS(=O) ₂ R', straight with 1 to 30 carbon atoms A chain, branched or cyclic alkyl group, a straight chain, branched or cyclic alkoxy group having 1 to 30 carbon atoms, a straight chain, branched or cyclic alkylthio group having 1 to 30 carbon atoms, a chain, branched or cyclic alkylthio group having 2 to 30 carbon atoms, Straight chain, branched or cyclic alkenyl group, straight chain, branched or cyclic alkynyl group having 2 to 30 carbon atoms, aromatic hydrocarbon group having 5 to 60 carbon atoms, heteroaromatic group having 5 to 60 carbon atoms , an aryloxy group having 5 to 40 carbon atoms, an arylthio group having 5 to 40 carbon atoms, an aralkyl group having 5 to 60 carbon atoms, a heteroaralkyl group having 5 to 60 carbon atoms, and a heteroaralkyl group having 10 to 40 carbon atoms. Diarylamino group, arylheteroarylamino group having 10 to 40 carbon atoms, or diheteroarylamino group having 10 to 40 carbon atoms.
Two or more adjacent R's may be bonded to each other to form an aliphatic or aromatic hydrocarbon or heteroaromatic monocyclic or fused ring.
The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group, and the alkynyl group may be further substituted with one or more R', and one -CH ₂ - group or two or more of these groups The non-adjacent -CH ₂ - groups of -C(-R')=C(-R')-, -C≡C-, -Si(-R') ₂ -, -C(=O) -, -NR'-, -O-, -S-, -CONR'- or a divalent aromatic hydrocarbon group may be substituted. Furthermore, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.
The aromatic hydrocarbon group, the heteroaromatic group, the aryloxy group, the arylthio group, the aralkyl group, the heteroaralkyl group, the diarylamino group, the arylheteroarylamino group, and the diheteroarylamino group , each independently may be further substituted with one or more R'.

[R']
R' each independently represents a hydrogen atom, D, F, Cl, Br, I, -N(R'') ₂ , -CN, -NO ₂ , -Si(R'') ₃ , -B(OR'') ₂ , -C(=O)R'', -P(=O)(R'') ₂ , -S(=O) ₂ R'', -OSO ₂ R'', carbon number 1 or more 30 The following straight chain, branched or cyclic alkyl groups, straight chain, branched or cyclic alkoxy groups having 1 to 30 carbon atoms, straight chain, branched or cyclic alkylthio groups having 1 to 30 carbon atoms, 2 or more carbon atoms Straight chain, branched or cyclic alkenyl group with 30 or less carbon atoms, straight chain, branched or cyclic alkynyl group with 2 to 30 carbon atoms, aromatic hydrocarbon group with 5 to 60 carbon atoms, 5 to 60 carbon atoms Heteroaromatic group, aryloxy group having 5 to 40 carbon atoms, arylthio group having 5 to 40 carbon atoms, aralkyl group having 5 to 60 carbon atoms, heteroaralkyl group having 5 to 60 carbon atoms, 10 carbon atoms It is selected from a diarylamino group having 40 or more carbon atoms, an arylheteroarylamino group having 10 to 40 carbon atoms, or a diheteroarylamino group having 10 to 40 carbon atoms.
Two or more adjacent R's may be bonded to each other to form an aliphatic or aromatic hydrocarbon or heteroaromatic monocyclic or fused ring.
The alkyl group, the alkoxy group, the alkylthio group, the alkenyl group, and the alkynyl group may be further substituted with one or more R'', and one -CH ₂ - group or two The above non-adjacent -CH ₂ - groups are -C(-R'')=C(-R'')-, -C≡C-, -Si(-R'') ₂ -, -C It may be replaced with (=O)-, -NR''-, -O-, -S-, -CONR''- or a divalent aromatic hydrocarbon group. Furthermore, one or more hydrogen atoms in these groups may be substituted with D, F, Cl, Br, I or -CN.
The aromatic hydrocarbon group, the heteroaromatic group, the aryloxy group, the arylthio group, the aralkyl group, the heteroaralkyl group, the diarylamino group, the arylheteroarylamino group, and the diheteroarylamino group , may be further substituted with one or more R''.

[R'']
R'' is each independently a hydrogen atom, D, F, -CN, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group having 1 to 20 carbon atoms. selected from heteroaromatic groups.
Two or more adjacent R'' may be bonded to each other to form an aliphatic or aromatic hydrocarbon or heteroaromatic monocyclic or fused ring.

(Specific examples of polycyclic heterocyclic compounds)
The polycyclic heterocyclic compound represented by formula (1) is not particularly limited, but specifically includes the following structures.

[Organometallic compound]
In the present invention, the organometallic compound refers to Groups 7 to 11 of the long period periodic table (hereinafter, unless otherwise specified, "periodic table" refers to the long period periodic table). Contains metals selected from. Preferred metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, and the like, with iridium or platinum being more preferred.
Preferably, the organometallic compound is a Werner type complex or an organometallic complex. Preferred ligands for the complex include ligands in which a (hetero)aryl group is linked to pyridine, pyrazole, phenanthroline, etc., such as (hetero)arylpyridine ligands and (hetero)arylpyrazole ligands. Pyridine ligands and phenylpyrazole ligands are preferred. Here, (hetero)aryl represents an aryl group or a heteroaryl group.

Due to the heavy atom effect of the metal, intersystem crossing from an excited singlet to an excited triplet occurs in an organometallic compound containing the metal, and the relaxation time from an excited triplet to a ground state is shortened to a certain extent. Furthermore, by satisfying the above-mentioned relational expression (E-1), the excited state generated by applying a voltage to the organic electroluminescent device can be converted into a light-emitting compound by both electron exchange interaction and dipole-dipole interaction. It is presumed that the light-emitting compound can be efficiently emitted.
Particularly preferred are organometallic complexes containing iridium. As the organometallic complex containing iridium, a metal compound represented by formula (201) is preferable.

[Ring A201 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ring A202 represents an aromatic heterocyclic structure which may have a substituent.
R ²⁰¹ and R ²⁰² each independently have a structure represented by the above formula (202).
When a plurality of R ²⁰¹ and R ²⁰² exist, they may be the same or different. Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon ring structure which may have a substituent. , or represents an aromatic heterocyclic structure which may have a substituent.
Ar ²⁰² is an aromatic hydrocarbon ring structure that may have a substituent, an aromatic heterocyclic structure that may have a substituent, or an aliphatic hydrocarbon structure that may have a substituent. represents.
When a plurality of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ exist, they may be the same or different.
* represents bonding to ring A201 or ring A202.
B ²⁰¹ -L ²⁰⁰ -B ²⁰² represents an anionic bidentate ligand. B ²⁰¹ and B ²⁰² each independently represent a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring, in which case B ²⁰¹ and/or B ²⁰² have a ring structure. represents. L ²⁰⁰ represents a single bond or an atomic group that constitutes a bidentate ligand together with B ²⁰¹ and B ²⁰² .
When a plurality of B ²⁰¹ -L ²⁰⁰ -B ²⁰² exist, they may be the same or different.
i1 and i2 each independently represent an integer from 0 to 12.
i3 is an integer of 0 or more with an upper limit of the number that can be replaced by Ar ²⁰² .
j is an integer of 0 or more with an upper limit of the number that can be replaced by Ar ²⁰¹ .
k1 and k2 are each independently an integer of 0 or more, with the upper limit being the number that can be substituted into ring A201 and ring A202.
m is an integer from 1 to 3. ]

(Ring A201, Ring A202)
The aromatic hydrocarbon ring in ring A201 is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms, and specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenyl ring, an acenaphthene ring, a fluoranthene ring, A fluorene ring is preferred.

The aromatic heterocycle in ring A201 is preferably an aromatic heterocycle having 3 to 30 carbon atoms and containing a nitrogen atom, an oxygen atom, or a sulfur atom as a hetero atom, and more preferably a furan ring or a benzofuran ring. , a thiophene ring, and a benzothiophene ring.

The ring A201 is more preferably a benzene ring, a naphthalene ring, or a fluorene ring, particularly preferably a benzene ring or a fluorene ring, and most preferably a benzene ring.

The aromatic heterocycle in ring A202 is preferably an aromatic heterocycle having 3 to 30 carbon atoms and containing a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom, and specifically, a pyridine ring. , pyrazine ring, pyrimidine ring, imidazole ring, oxazole ring, and thiazole ring, most preferably a pyridine ring.

When m is 2 or 3, the plurality of rings A201 and the plurality of rings A202 may be the same or different.

Preferred combinations of ring A201 and ring A202, when expressed as (ring A201-ring A202), are (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring- (quinazoline ring), (benzene ring-imidazole ring), (benzene ring-benzothiazole ring), and most preferably (benzene ring-pyridine ring).

The substituents that ring A201 and ring A202 may have can be arbitrarily selected, but are preferably one or more substituents selected from substituent group S described below.

The substituents bonded to ring A201, the substituents bonded to ring A202, or the substituents bonded to ring A201 and the substituents bonded to ring A202 may bond to each other to form a ring.

(R ²⁰¹ , R ²⁰² )
R ²⁰¹ and R ²⁰² are each independently a structure represented by the above formula (202), and “*” represents bonding to ring A201 or ring A202. R ²⁰¹ and R ²⁰² may be the same or different. When a plurality of R ²⁰¹ and R ²⁰² exist, they may be the same or different. That is, when multiple R ^201s exist, they may be the same or different; when multiple R ^202s exist, they may be the same or different.

(Ar ²⁰¹ , Ar ²⁰² , Ar ²⁰³ )
Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon ring structure that may have a substituent or an aromatic heterocyclic structure that may have a substituent.
Ar ²⁰² is an aromatic hydrocarbon ring structure that may have a substituent, an aromatic heterocyclic structure that may have a substituent, or an aliphatic hydrocarbon structure that may have a substituent. represents.
When a plurality of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ exist, they may be the same or different. That is, when there are multiple Ar ^201s , they may be the same or different; when there are multiple Ar ^202s , they may be the same or different; and when there are multiple Ar ^203s , they may be the same or different. If so, they may be the same or different.
When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is an aromatic hydrocarbon ring structure which may have a substituent, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring structure having 6 to 30 carbon atoms. It is a hydrocarbon ring, and specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenyl ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring are preferable, and a benzene ring, a naphthalene ring, and a fluorene ring are more preferable, and the most preferable are a benzene ring, a naphthalene ring, and a fluorene ring. Preferably it is a benzene ring.

When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is a fluorene ring that may have a substituent, the 9- and 9'-positions of the fluorene ring have a substituent or are bonded to adjacent structures. It is preferable that

When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is a benzene ring which may have a substituent, it is preferable that at least one benzene ring is bonded to an adjacent structure at the meta or para position. More preferably, at least one benzene ring is bonded to an adjacent structure at the meta position.

When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is an aromatic heterocyclic structure which may have a substituent, the aromatic heterocyclic structure preferably contains a nitrogen atom, an oxygen atom, or An aromatic heterocycle having 3 to 30 carbon atoms and containing any sulfur atom, specifically a pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring , a benzoxazole ring, a benzimidazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring, a naphthyridine ring, a phenanthridine ring, a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring, and more preferably a pyridine ring and a pyrimidine ring. ring, triazine ring, carbazole ring, dibenzofuran ring, and dibenzothiophene ring.

When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is a carbazole ring which may have a substituent, the N-position of the carbazole ring may have a substituent or be bonded to an adjacent structure. preferable.

When Ar ²⁰² is an aliphatic hydrocarbon structure which may have a substituent, the aliphatic hydrocarbon structure is an aliphatic hydrocarbon structure having a linear, branched, or cyclic structure, preferably a carbon It is an aliphatic hydrocarbon having a carbon number of 1 or more and 24 or less, more preferably an aliphatic hydrocarbon having a carbon number of 1 or more and 12 or less, and even more preferably an aliphatic hydrocarbon having a carbon number of 1 or more and 8 or less.

(i1, i2, i3, j, k1, k2)
i1 and i2 are each independently preferably an integer of 1 to 12, more preferably an integer of 1 to 8, and even more preferably an integer of 1 to 6. Within this range, it is expected that solubility and charge transport properties will be improved.

i3 preferably represents an integer of 0 to 5, more preferably an integer of 0 to 2, and more preferably 0 or 1.

j preferably represents an integer of 0 to 2, more preferably 0 or 1.

k1 and k2 preferably represent an integer of 0 to 3, more preferably an integer of 1 to 3, more preferably 1 or 2, particularly preferably 1.

The substituents that Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ may have can be arbitrarily selected, but are preferably one or more substituents selected from the substituent group S described below, and more preferably hydrogen An atom, an alkyl group, or an aryl group, particularly preferably a hydrogen atom or an alkyl group, and most preferably an unsubstituted (hydrogen atom).

Unless otherwise specified, the substituent is preferably a group selected from the following substituent group S.

(Substituent group S)
・Alkyl group, preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 8 carbon atoms, particularly preferably an alkyl group having 1 to 6 carbon atoms . Alkyl groups may be straight chain or branched.
-Alkoxy group, preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, still more preferably an alkoxy group having 1 to 6 carbon atoms.
-Aryloxy group, preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, even more preferably an aryloxy group having 6 to 12 carbon atoms, particularly preferably an aryloxy group having 6 to 12 carbon atoms Aryloxy group.
- Heteroaryloxy group, preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms.
- An alkylamino group, preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms.
- An arylamino group, preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms.
-Aralkyl group, preferably an aralkyl group having 7 to 40 carbon atoms, more preferably an aralkyl group having 7 to 18 carbon atoms, even more preferably an aralkyl group having 7 to 12 carbon atoms.
- Heteroaralkyl group, preferably a heteroaralkyl group having 7 to 40 carbon atoms, more preferably a heteroaralkyl group having 7 to 18 carbon atoms.
・Alkenyl group, preferably an alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, still more preferably an alkenyl group having 2 to 8 carbon atoms, particularly preferably an alkenyl group having 2 to 6 carbon atoms .
- An alkynyl group, preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms.
-Aryl group, preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, still more preferably an aryl group having 6 to 18 carbon atoms, particularly preferably an aryl group having 6 to 14 carbon atoms .
・Heteroaryl group, preferably a heteroaryl group having 3 to 30 carbon atoms, more preferably a heteroaryl group having 3 to 24 carbon atoms, still more preferably a heteroaryl group having 3 to 18 carbon atoms, particularly preferably a heteroaryl group having 3 to 30 carbon atoms 14 heteroaryl groups.
- An alkylsilyl group, preferably an alkylsilyl group in which the alkyl group has 1 to 20 carbon atoms, more preferably an alkylsilyl group in which the alkyl group has 1 to 12 carbon atoms.
- An arylsilyl group, preferably an arylsilyl group in which the aryl group has 6 to 20 carbon atoms, more preferably an arylsilyl group in which the aryl group has 6 to 14 carbon atoms.
- An alkylcarbonyl group, preferably an alkylcarbonyl group having 2 to 20 carbon atoms.
-Arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms.
- Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF ₅ .

In the above groups, one or more hydrogen atoms may be replaced with a fluorine atom, or one or more hydrogen atoms may be replaced with a deuterium atom.

Unless otherwise specified, aryl is an aromatic hydrocarbon and heteroaryl is an aromatic heterocycle.

(Preferred group in substituent group S)
Among these substituent groups S, preferred are alkyl groups, alkoxy groups, aryloxy groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, heteroaryl groups, alkylsilyl groups, arylsilyl groups, and A group in which one or more hydrogen atoms are replaced with a fluorine atom, a fluorine atom, a cyano group, or _-SF5 , more preferably an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, or a hetero group. Aryl group, a group in which one or more hydrogen atoms of these groups is replaced with a fluorine atom, a fluorine atom, a cyano group, or _-SF5 , more preferably an alkyl group, an alkoxy group, an aryloxy group , an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group,
Particularly preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups, and heteroaryl groups, and most preferred are alkyl groups, arylamino groups, aralkyl groups, aryl groups, and heteroaryl groups.

These substituent groups S may further have a substituent selected from the substituent group S as a substituent. Preferable groups, more preferable groups, still more preferable groups, particularly preferable groups, and most preferable groups of the substituents that may be included are the same as the preferable groups in substituent group S, etc.

(Preferred structure of formula (201))
Among the structures represented by the above formula (202) in the above formula (201), structures having a group to which benzene rings are connected, aromatic hydrocarbons in which an alkyl group or an aralkyl group is bonded to ring A201 or ring A202. A structure having a group or an aromatic heterocyclic group, and a structure in which a dendron is bonded to ring A201 or ring A202 are preferable.

In a structure having a group in which a benzene ring is connected, Ar ²⁰¹ is a benzene ring structure, i1 is 1 to 6, and at least one benzene ring is bonded to an adjacent structure at an ortho position or a meta position. .
This structure is expected to improve solubility and charge transport properties.

In a structure having an aromatic hydrocarbon group or an aromatic heterocyclic group to which an alkyl group or an aralkyl group is bonded to ring A201 or ring A202,
Ar ²⁰¹ is an aromatic hydrocarbon structure or an aromatic heterocyclic structure, i1 is 1 to 6, Ar ²⁰² is an aliphatic hydrocarbon structure, and i2 is 1 to 12, preferably 3 to 8; , Ar ²⁰³ is a benzene ring structure, and i3 is 0 or 1.
In the case of this structure, Ar ²⁰¹ is preferably the aromatic hydrocarbon structure described above, more preferably a structure in which 1 to 5 benzene rings are connected, and more preferably one benzene ring.
This structure is expected to improve solubility and charge transport properties.

In a structure in which a dendron is bonded to ring A201 or ring A202, Ar ²⁰¹ and Ar ²⁰² are benzene ring structures, Ar ²⁰³ is a biphenyl or terphenyl structure, i1 and i2 are 1 to 6, and i3 is 2, and j is 2.
This structure is expected to improve solubility and charge transport properties.

(Structure represented by B ²⁰¹ -L ²⁰⁰ -B ²⁰² )
When a plurality of B ²⁰¹ -L ²⁰⁰ -B ²⁰² exist, they may be the same or different.
The structure represented by B ²⁰¹ -L ²⁰⁰ -B ²⁰² is preferably a structure represented by the following formula (203) or (204).

R ²¹¹ , R ²¹² and R ²¹³ represent a substituent.
Although the substituent is not particularly limited, it is preferably a group selected from the above-mentioned substituent group S.

Ring B3 represents a nitrogen atom-containing aromatic heterocyclic structure which may have a substituent.
Ring B3 is preferably a pyridine ring.
Although the substituent that ring B3 may have is not particularly limited, it is preferably a group selected from the above-mentioned substituent group S.

(molecular weight)
There is no particular upper limit to the molecular weight of the organometallic compound, but it is preferably 10,000 or less, more preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less. Further, the molecular weight of the organometallic compound is 1200 or more, preferably 1300 or more, and more preferably 1700 or more. By being within this molecular weight range, the organometallic compound does not aggregate and can be uniformly mixed with the aromatic compound of the present invention and/or other charge transport materials to obtain a luminescent layer with high luminous efficiency and long luminescent life. It seems possible.

The molecular weight of the organometallic compound is high in Tg, melting point, decomposition temperature, etc., the organometallic compound and the formed light emitting layer have excellent heat resistance, and the film quality due to gas generation, recrystallization, molecular migration, etc. A larger value is preferable in that it is less likely to cause a decrease in the concentration of impurities or an increase in impurity concentration due to thermal decomposition of the material. On the other hand, the molecular weight of the organometallic compound is preferably small in terms of ease of purification of the organic compound.

Further, when the molecular weight of the organometallic compound is MwA and the molecular weight of the light emitting compound is MwB, MwA/MwB is preferably 1.0 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. be. It is considered that by setting MwA/MwB within this range, energy is appropriately transferred from the organometallic compound to the light-emitting compound, and a light-emitting layer with high light-emitting efficiency and long light-emitting life can be obtained.

(Specific examples of organometallic compounds)
The organometallic compound represented by formula (201) is not particularly limited, but specifically includes the following structures.
In addition, Me means a methyl group, and Ph means a phenyl group.

[Host material]
Preferably, the light-emitting layer further contains a host material. That is, it is preferable that the material for the light emitting layer of the organic electroluminescent device of the present invention further contains a host material. The host material is preferably a charge transport material, and those conventionally used as materials for organic electroluminescent devices can be used. The charge transport material used as the host material of the light emitting layer is a material having a skeleton with excellent charge transport properties, and is selected from electron transport materials, hole transport materials, and bipolar materials capable of transporting both electrons and holes. It is preferable. Furthermore, in the present invention, the term "charge transporting material" includes materials that adjust charge transportability.
Specific examples of skeletons with excellent charge transport properties include pyridine, pyrimidine, triazine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, and acetonaphthofluorane. Thene, coumarin, p-bis(2-phenylethenyl)benzene and their derivatives, quinacridone derivatives, DCM (4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) based compounds, Examples include benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, fused aromatic ring compounds substituted with an arylamino group, and styryl derivatives substituted with an arylamino group.

One type of these may be used alone, or two or more types may be used in any combination and ratio.

Among these, preferred are pyridine, pyrimidine, triazine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, acetonaphthofluoranthene and derivatives thereof, More preferred are anthracene derivatives.

Specific examples of skeletons with excellent charge transport properties include aromatic structures, aromatic amine structures, triarylamine structures, dibenzofuran structures, naphthalene structures, phenanthrene structures, phthalocyanine structures, porphyrin structures, thiophene structures, benzylphenyl structures, Examples include a fluorene structure, a quinacridone structure, a triphenylene structure, a carbazole structure, a pyrene structure, an anthracene structure, a phenanthroline structure, a quinoline structure, a pyridine structure, a pyrimidine structure, a triazine structure, an oxadiazole structure, and an imidazole structure.

As the electron transport material, a compound having a skeleton with excellent electron transport properties and a relatively stable pyridine structure, pyrimidine structure, or triazine structure is more preferable, and a compound having a pyrimidine structure or triazine structure is even more preferable. . Particularly preferred as the electron transport material is a compound represented by formula (250) described below.

The hole transport material is a compound having a structure with excellent hole transport properties, and among the skeletons with excellent charge transport properties, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure is preferable. A structure with excellent hole transport properties is preferred, and a carbazole structure, dibenzofuran structure, or triarylamine structure is more preferred. Particularly preferred as the hole transport material is a compound represented by formula (240) described below.

As the bipolar material capable of transporting both electrons and holes, a material having both a skeleton with excellent electron transport properties and a skeleton with excellent hole transport properties is preferable.
As the material for adjusting the charge transport property, a compound represented by the below-mentioned formula (260), which is a compound having a structure in which a large number of benzene rings are connected, is preferable. By including this compound as a host material, the excitons generated within the light emitting layer are thought to recombine efficiently, increasing the luminous efficiency, and the charge transport properties within the light emitting layer are appropriately adjusted, making the light emitting material It is thought that this will suppress deterioration and extend the drive life.

The charge transport material used as the host material of the light emitting layer is preferably a compound having a fused ring structure of 3 or more rings, and is preferably a compound having 2 or more fused ring structures of 3 or more rings, or a compound having at least 5 fused rings. It is more preferable that the compound has one. These compounds increase the rigidity of molecules, making it easier to obtain the effect of suppressing the degree of molecular motion in response to heat. Further, the fused rings of 3 or more rings and the fused rings of 5 or more rings preferably have an aromatic hydrocarbon ring or an aromatic heterocycle from the viewpoint of charge transportability and material durability.

Specifically, the fused ring structure of three or more rings includes an anthracene structure, a phenanthrene structure, a pyrene structure, a chrysene structure, a naphthacene structure, a triphenylene structure, a fluorene structure, a benzofluorene structure, an indenofluorene structure, an indrofluorene structure, Examples include a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure.

Among fused ring structures of three or more rings, from the viewpoint of charge transport properties and solubility, phenanthrene structure, fluorene structure, indenofluorene structure, carbazole structure, indenocarbazole structure, indolocarbazole structure, dibenzofuran structure and dibenzothiophene structure At least one structure selected from the group consisting of structures is preferable, and from the viewpoint of durability against charges, a carbazole structure or an indolocarbazole structure is more preferable.

[(Group A), (Group B), (Group C)]
Here, in this specification, host materials that may be included in the light emitting layer are referred to as (group A), (group B), and (group C) as follows for convenience.
(Group A) Electron transport material, preferably a compound represented by the following formula (250) (Group B) Hole transport material, preferably a compound represented by the following formula (240) (Group C) Charge transport properties A material for adjusting, preferably a compound represented by the following formula (260)

In the present invention, the host material that can be included in the light-emitting layer is at least one selected from at least one of the three groups represented by (Group A), (Group B), and (Group C). It is preferable to include a compound of
More preferably, it contains at least one compound selected from the above (group A) or the above (group B),
Contains at least two types of compounds selected from each of at least two arbitrary groups among the three groups represented by the above (group A), the above (group B), and the above (group C). It is even more preferable that
More preferably, it contains at least two compounds selected from each of the two groups represented by the above (Group A) and the above (Group B),
It is particularly preferable that the composition contains at least three types of compounds selected from each of the three groups represented by (Group A), (Group B), and (Group C).
Note that the number of compounds selected from each group may be one or two or more.

The compound selected from (Group A) is preferably a compound represented by the following formula (250), the compound selected from (B group) is preferably a compound represented by the following formula (240), and (Group C) The compound selected from is preferably a compound represented by the following formula (260),
The host material contained in the light-emitting layer is at least any two of the compounds represented by the following formula (250), the compound represented by the following formula (240), and the compound represented by the following formula (260). It is more preferable that at least one of each compound is selected from at least two kinds of compounds.
It is more preferable that at least two kinds of compounds each selected from a compound represented by the following formula (250) and a compound represented by the following formula (240) are included,
It may contain at least three kinds of compounds selected from each of the compound represented by the following formula (250), the compound represented by the following formula (240), and the compound represented by the following formula (260). Particularly preferred.

When the organic electroluminescent device of the present invention contains, as a host material, a compound represented by the above formula (250), which is a compound having a structure in which a six-membered heteroaromatic ring containing nitrogen and a benzene ring are connected, in the light emitting layer, The charge transport properties within the light emitting layer are appropriately adjusted, the voltage is reduced, the luminous efficiency is improved, and the polycyclic heterocyclic compound represented by the above formula (1) and the above formula (201), which are light emitting materials, are It is thought that the deterioration of the organometallic compound that is produced can be suppressed and the driving life will be extended. In particular, when W in formula (250) has a triazine structure in which all nitrogen atoms are present, the LUMO is relatively deep and has appropriate electron trapping properties in addition to electron transport properties, and is expressed by formula (1) above. By not supplying excessive electrons to the polycyclic heterocyclic compound and the organometallic compound represented by the formula (201), the polycyclic heterocyclic compound represented by the formula (1) and the organic metal compound represented by the formula (201), which are luminescent materials, ) It is thought that the durability of the organometallic compound represented by the above formula is improved, and as a result, the operating life of the organic electroluminescent device becomes longer. In particular, an electron enters the empty p orbital of the boron atom of the polycyclic heterocyclic compound represented by formula (1), which is a luminescent material, and the polycyclic heterocyclic compound represented by formula (1), which is a luminescent material, It is thought that there is a possibility of suppressing the deterioration of the ring compound and the organometallic compound represented by the above formula (201).

Furthermore, the compound represented by the formula (250) has a 6-membered aromatic ring having a nitrogen atom at the center, and therefore has high electron transport properties. Therefore, when using the compound represented by the above formula (250) as a host, it is thought that by using a host material with high hole transport properties as another host material, the voltage can be lowered and the driving life will be increased. It will be done.

When the organic electroluminescent device of the present invention contains a compound represented by the above formula (240), which is a compound containing a structure having two carbazole rings, as a host material in the light emitting layer, the charge transport property in the light emitting layer is improved. is appropriately adjusted, the voltage can be lowered, and the deterioration of the polycyclic heterocyclic compound represented by the above formula (1) and the organometallic compound represented by the above formula (201), which are luminescent materials, can be suppressed. It is thought that the drive life will be longer. When the polycyclic heterocyclic compound represented by the above formula (1) or the organometallic compound represented by the above formula (201), which is a light emitting material, directly receives the holes injected from the layer on the anode side and becomes an oxidized state. If there is a possibility of deterioration, the compound represented by the formula (240) above has a hole transporting property and easily receives holes from the layer on the anode side. It is thought that the polycyclic heterocyclic compound represented by the above formula (201) or the organometallic compound represented by the formula (201) is difficult to be directly oxidized, and deterioration is suppressed. Conversely, when the polycyclic heterocyclic compound represented by the above formula (1) or the organometallic compound represented by the above formula (201), which is a luminescent material, directly receives electrons injected from the cathode side and enters a reduced state. If the compound represented by formula (240) is easily degraded, the polycyclic heterocyclic compound represented by the above formula (1) or the organometallic compound represented by the above formula (201), which is a light emitting material, is immediately transferred from the compound represented by the formula (240). It is thought that deterioration is suppressed by the transport of holes and the recombination of the luminescent material to emit light.

The compound represented by formula (240) has excellent hole transport properties, and has excellent hole transport properties to the organometallic compound represented by formula (201). In addition, since the compound represented by formula (240) has two carbazole structures with high planarity, it can be converted into a polycyclic heterocyclic compound represented by formula (1), which is a polycyclic heterocyclic compound with high planarity. This is thought to improve the hole transport properties of . At this time, electrons are quickly supplied to the polycyclic heterocyclic compound represented by the formula (1), which is the luminescent material, so that recombination causes rapid luminescence, and deterioration of the luminescent material is also suppressed. . Therefore, by using a compound represented by the formula (240) as the first host and a material with high electron transport properties as the second host material, an organic electroluminescent device with low voltage and long operating life can be produced. It is thought that it can be obtained. As a host with high electron transport properties, a compound represented by the above formula (250) is preferable.

When the organic electroluminescent device of the present invention contains a compound represented by the formula (260), which is a compound having a structure in which a large number of benzene rings are connected, as a host material in the light emitting layer, the charge transport property in the light emitting layer is improved. is appropriately adjusted, the deterioration of the polycyclic heterocyclic compound represented by formula (1) or the organometallic compound represented by formula (201), which is the luminescent material, can be suppressed, and the driving life is long. It is considered to be. In particular, the compound represented by formula (260) has the effect of suppressing charge transport properties. In particular, when a compound represented by formula (250) with excellent electron transport properties is used as a host, by further adding a compound represented by formula (260) as a host material, it is possible to The polycyclic heterocyclic compound represented by the formula (201) or the organometallic compound represented by the formula (201) is suppressed in its electron transport property in the light emitting layer so that it does not deteriorate due to excessive reduction, and the driving life of the device is extended. Conceivable.

<Definition of substituents>
The substituents that the host material may have are selected from substituent group Z2.
<Substituent group Z2>
Substituent group Z2 includes an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an arylalkylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, This is a group consisting of an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may have any linear, branched, or cyclic structure.

More specifically, the substituent group Z2 includes the following structures.
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc. , straight chain, branched, having a carbon number of usually 1 or more, preferably 4 or more, usually 24 or less, preferably 12 or less, more preferably 8 or less, still more preferably 6 or less , or a cyclic alkyl group;
For example, an alkoxy group, such as a methoxy group or an ethoxy group, whose carbon number is usually 1 or more and usually 24 or less, preferably 12 or less;
For example, an aryloxy group or a heteroaryloxy group, such as a phenoxy group, a naphthoxy group, or a pyridyloxy group, which usually has 4 or more carbon atoms, preferably 5 or more carbon atoms, and usually has 36 or less carbon atoms, and preferably 24 or less carbon atoms. Base;
For example, an alkoxycarbonyl group, such as a methoxycarbonyl group or an ethoxycarbonyl group, which usually has 2 or more carbon atoms, usually 24 or less, and preferably 12 or less;
For example, a dialkylamino group, such as a dimethylamino group or a diethylamino group, whose carbon number is usually 2 or more and usually 24 or less, preferably 12 or less;
For example, a diarylamino group, such as a diphenylamino group or a ditolylamino group, usually having a carbon number of 10 or more, preferably 12 or more, and usually 36 or less, preferably 24 or less;
For example, an arylalkylamino group, such as a phenylmethylamino group, whose carbon number is usually 7 or more, usually 36 or less, and preferably 24 or less;
For example, an acyl group such as an acetyl group or a benzoyl group, which usually has 2 or more carbon atoms and usually has 24 or less carbon atoms, preferably 12 or less carbon atoms;
For example, halogen atoms such as fluorine atoms and chlorine atoms;
For example, a haloalkyl group, such as a trifluoromethyl group, whose carbon number is usually 1 or more, usually 12 or less, and preferably 6 or less;
For example, an alkylthio group such as a methylthio group or an ethylthio group, the number of carbon atoms is usually 1 or more and usually 24 or less, preferably 12 or less;
For example, an arylthio group having a carbon number of usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, or a pyridylthio group;
For example, a silyl group such as a trimethylsilyl group or a triphenylsilyl group, which usually has 2 or more carbon atoms, preferably 3 or more carbon atoms, and usually has 36 or less carbon atoms, and preferably 24 or less carbon atoms;
For example, a siloxy group having a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less, such as a trimethylsiloxy group or a triphenylsiloxy group;
Cyano group;
For example, an aromatic hydrocarbon group having a carbon number of usually 6 or more, usually 36 or less, and preferably 24 or less, such as a phenyl group or a naphthyl group;
For example, an aromatic heterocyclic group such as a thienyl group or a pyridyl group, which usually has 3 or more carbon atoms, preferably 4 or more carbon atoms, and usually has 36 or less carbon atoms, and preferably 24 or less carbon atoms.

Among the above substituent group Z2, preferably an alkyl group, an alkoxy group, a diarylamino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. From the viewpoint of charge transportability, the substituent is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, more preferably an aromatic hydrocarbon group, and even more preferably no substituent. From the viewpoint of improving solubility, the substituent is preferably an alkyl group or an alkoxy group.

Furthermore, each substituent in the above substituent group Z2 may further have a substituent. Examples of these substituents include the same substituents as described above (substituent group Z2). Each substituent that the above substituent group Z2 may have is preferably an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group having 6 or less carbon atoms, It is an alkoxy group having 6 or less carbon atoms or a phenyl group, and it is more preferable that each substituent in the above substituent group Z2 has no further substituent from the viewpoint of charge transport properties.

A substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms in Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² and Za ² may have, and the aromatic group having 3 to 30 carbon atoms The substituents that the heterocyclic group may have are preferably each independently selected from the substituent group Z2, and the substituents selected from the substituent group Z2 have no further substituents. It is more preferable.

The compound represented by the above formula (250) is preferably a charge-transporting compound, that is, a charge-transporting host material.

<W>
W in the formula (250) represents CH or N, and at least one of them is N, but from the viewpoint of electron transport properties and electron durability, it is preferable that at least two of them are N, and all of them are N. It is more preferable that there be.

<Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² , Za ² >
In the formula (250), when Xa ¹ , Ya ¹ and Za ¹ are divalent aromatic hydrocarbon groups having 6 to 30 carbon atoms which may have a substituent, and Xa ² and Ya ² , when Za ² is an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, the aromatic hydrocarbon ring of the aromatic hydrocarbon group having 6 to 30 carbon atoms is 6 A single membered ring or 2 to 5 condensed rings is preferred. Specific examples include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, a fluoranthene ring, and an indenofluorene ring. Among them, preferred are a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, or fluorene ring, more preferred are a benzene ring, naphthalene ring, phenanthrene ring, or fluorene ring, and still more preferred are a benzene ring, naphthalene ring, or fluorene ring. be. Furthermore, -Xa 1 -Xa 2 is the terminal partial structure when g11 is 2 or more, -Ya ¹ -Ya ² is the terminal partial structure when h11 is ² or more, and when ^j11 is 2 In the above case, the terminal partial structure -Za ¹ -Za ² may be a spirofluorene structure. The compound represented by formula (250) has -Xa ¹ -Xa ² which is the terminal partial structure when g11 is 2 or more, and -Ya which is the terminal partial structure when h11 is 2 or more. It is preferable that at least one of ¹ -Ya ² and -Za ¹ -Za ² , which is the terminal partial structure when j11 is 2 or more, is a spirofluorene structure.

In the above formula (250), when Xa ¹ , Ya ¹ and Za ¹ are divalent aromatic heterocyclic groups having 3 to 30 carbon atoms which may have a substituent, and Xa ² and Ya ² , when Za ² is an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, the aromatic heterocycle of the aromatic heterocyclic group having 3 to 30 carbon atoms is 5 or A 6-membered monocyclic ring or a 2 to 5 fused ring is preferred. Specifically, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, indolocarbazole ring, indenocarbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, Examples include a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a shinoline ring, a quinoxaline ring, a perimidine ring, a quinazoline ring, and a quinazolinone ring. Among these, preferred are a thiophene ring, a pyrrole ring, an imidazole ring, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, an indolocarbazole ring, a phenanthroline ring, or an indenocarbazole ring. and more preferably a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, an indolocarbazole ring, an indenocarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring, and even more preferably a carbazole ring or an indolocarbazole ring. They are a locarbazole ring, a dibenzofuran ring, or a dibenzothiophene ring.

In Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² , and Za ² in the formula (250), a particularly preferable aromatic hydrocarbon ring is a benzene ring, a naphthalene ring, or a phenanthrene ring. The heterocycle is a carbazole ring, indolocarbazole ring, dibenzofuran ring or dibenzothiophene ring.

The substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms in Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² and Za ² in the formula (250) may have, and the carbon number The substituents that the 3 to 30 aromatic heterocyclic groups may have are preferably each independently selected from the substituent group Z2, and the substituents selected from the substituent group Z2 are further It is more preferable to have no substituent. It is preferable that the substituent selected from substituent group Z2 does not have any further substituents because it is considered that high charge transport properties and durability can be maintained.
Moreover, among the substituent group Z2, aromatic hydrocarbon groups and aromatic heterocyclic groups are preferable from the viewpoints of charge transportability and durability, and aromatic hydrocarbon groups are particularly preferable.

<g11, h11, j11>
g11, h11, and j11 each independently represent an integer of 0 to 6, and at least one of g11, h11, and j11 is an integer of 1 or more. From the viewpoint of charge transportability and durability, it is preferable that g11 is 2 or more, or that at least one of h11 and j11 is 3 or more.

In addition, the compound represented by the formula (250) has a total of 8 to 18 rings, including the ring with three central W atoms, which improves charge transport properties, durability, and resistance to organic solvents. preferred from the viewpoint of solubility.

<(Xa ¹ ) _g11 , (Ya ¹ ) _h11, (Za ¹ ) _j11 >
At least one group selected from (Xa ¹ ) _g11 , (Ya ¹ ) _h11, and (Za ¹ ) _j11 is each independently represented by the following formula (11) from the viewpoint of solubility and durability of the compound. It is preferable to have a partial structure selected from a partial structure represented by the following formula (12), and a partial structure represented by the following formula (13). ¹ ) (Ya ¹ ) h11 when _g11 and _{h11 are 1 or more,} and (Za ¹ ) _j11 when j11 is 1 or more are each independently a partial structure represented by the following formula (11), the following: It is more preferable to have a partial structure selected from a partial structure represented by formula (12) and a partial structure represented by formula (13) below.

In each of the above formulas (11) to (13), * represents a bonding position with an adjacent structure or a hydrogen atom when Xa ² , Ya ² or Za ² is a hydrogen atom. At least one of the two * represents a bonding position with an adjacent structure. In the following description, the definition of * is the same unless otherwise specified.

More preferably, (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) _h11 when h11 is 1 or more, and (Za ¹ ) _j11 when j11 is 1 or more are each independently , has a partial structure represented by formula (11) or a partial structure represented by formula (12).
More preferably, (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) _h11 when h11 is 1 or more, and (Za ¹ ) _j11 when j11 is 1 or more are each independently , has a partial structure represented by formula (11) and a partial structure represented by formula (12).

The partial structure represented by formula (12) is preferably a partial structure represented by formula (12-2) below.

The partial structure represented by formula (12) is more preferably a partial structure represented by formula (12-3) below.

As a partial structure having a partial structure represented by formula (11) and a partial structure represented by formula (12), from the partial structure represented by formula (11) and the partial structure represented by formula (12), A partial structure selected from the following formulas (14) to (17), which is a structure containing a plurality of selected structures, is preferable. That is, (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) _{h11 when h11 is 1 or more,} and (Za ¹ ) _j11 when j11 is 1 or more are each independently expressed as above. It is preferable to have a partial structure selected from Formula (11) to Formula (13) above and Formula (14) to Formula (17) below. In other words, from the viewpoint of solubility, (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) _{h11 when h11 is 1 or more,} and (Za ¹ ) when j11 is 1 or more. Preferably, _j11 each independently has a partial structure selected from formulas (11) to (17).

A structure including a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12) means, for example, the partial structure represented by formula (14) is the structure represented by the following formula (14a ), it is a partial structure that can be considered to have one partial structure represented by formula (11) and two partial structures represented by formula (12).

More preferably, at least one of (Xa ¹ ) _g11 , (Ya ¹ ) _h11, and (Za ¹ ) _j11 has at least a partial structure represented by formula (14) or a partial structure represented by formula (15). has. More preferably, (Xa ¹ ) _g11 when g11 is 1 or more, (Ya ¹ ) _h11 when h11 is 1 or more, and (Za ¹ ) _j11 when j11 is 1 or more are expressed by the formula ( It has a partial structure represented by formula (14) or formula (15).

The partial structure represented by formula (14) is preferably a partial structure represented by formula (14-2) below.

The partial structure represented by formula (14) is more preferably a partial structure represented by formula (14-3) below.

The partial structure represented by formula (15) is preferably a partial structure represented by formula (15-2) below.

The partial structure represented by formula (15) is more preferably a partial structure represented by formula (15-3) below.

The partial structure represented by formula (17) is preferably a partial structure represented by formula (17-2) below.

At least one of (Xa ¹ ) _g11 , (Ya ¹ ) _h11, and (Za ¹ ) _j11 is a moiety represented by the following formula (19) as a partial structure containing the partial structure represented by formula (13). It is more preferable to have a structure or a partial structure represented by the following formula (20).

In each of the above formulas (14) to (20), * represents a bonding position with an adjacent structure or a hydrogen atom when Xa ² , Ya ² or Za ² is a hydrogen atom. At least one of the two * represents a bonding position with an adjacent structure.

Among the partial structures represented by formulas (14) to (20), the partial structures represented by formula (14-3) and the partial structure represented by formula (15-3) are preferable, and the partial structures represented by formula (14) -3) is more preferred.

-(Xa ¹ ) _g11 -(Xa ² ), -(Ya ¹ ) _h11 -(Ya ² ), and -(Za ¹ ) _j11 -(Za ² ) are each independently represented by formula (11) It is preferable to have a partial structure, a partial structure represented by formula (12-3), a partial structure represented by formula (14-3), or a partial structure represented by formula (15-3).

Furthermore, at least one of -(Xa ¹ ) _g11 -(Xa ² ), -(Ya ¹ ) _h11 -(Ya ² ), and -(Za ¹ ) _j11 -(Za ² ) is represented by the following formula (250-1 ) to the following formula (250-10) or a terminal structure.

The substituents that these structures may have are the same as ^R32 .

Ar ²⁵⁰ is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group or a biphenyl group, and even more preferably a phenyl group.

In a structure having two R ^32s , the two R ^32s may be the same or different.
R ³² is preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms. A silyl group, an arylsilyl group having 6 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, or an alkyl group having 1 to 8 carbon atoms. A heteroaryl group having 3 to 30 carbon atoms, more preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a heteroaryl group having 6 to 20 carbon atoms. 20 aryloxy group, an aryl group having 6 to 30 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and an alkyl group having 7 to 20 carbon atoms. an aralkyl group having 1 to 8 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, and an aryl group having 6 to 14 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms.

^<R31>
When R ³¹ is a substituent, it is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent. is a group heterocyclic group. From the viewpoint of improving durability and charge transportability, an aromatic hydrocarbon group which may have a substituent is more preferable. When multiple R ^31s are present as substituents, they may be different from each other.

A substituent that the above-mentioned aromatic hydrocarbon group having 6 to 30 carbon atoms may have, a substituent that may have the aromatic heterocyclic group having 3 to 30 carbon atoms, and R ³¹ which is a substituent. The substituent that may have can be selected from the substituent group Z2.

From the viewpoint of charge transport properties, R ³¹ is preferably a hydrogen atom.

Furthermore, from the viewpoint of solubility, it is preferable that -(Ya ¹ ) _h11 -(Ya ² ) and -(Za ¹ ) _j11 -(Za ² ) are not unsubstituted phenyl groups at the same time.

<Molecular weight>
The compound represented by the formula (250) is a low-molecular material, and the molecular weight is preferably 3,000 or less, more preferably 2,500 or less, particularly preferably 2,000 or less, and most preferably 1 ,500 or less. The lower limit of the molecular weight of the compound is usually 400 or more, preferably 500 or more, more preferably 600 or more.

<Specific examples of compounds represented by formula (250)>
The compound represented by formula (250) is not particularly limited, and examples thereof include the following compounds.

The light-emitting layer and composition of the organic electroluminescent device of the present invention may contain only one type of compound represented by the above formula (250), or may contain two or more types. .

<Ar ⁶¹¹ , Ar ⁶¹² >
Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.
The aromatic hydrocarbon group preferably has 6 to 50 carbon atoms, more preferably 6 to 30 carbon atoms, and still more preferably 6 to 18 carbon atoms. Specifically, the aromatic hydrocarbon group usually has 6 carbon atoms, such as a benzene ring, a naphthalene ring, an anthracene ring, a tetraphenylene ring, a phenanthrene ring, a chrysene ring, a pyrene ring, a benzanthracene ring, or a perylene ring. A monovalent group having an aromatic hydrocarbon structure having a number of usually 30 or less, preferably 18 or less, more preferably 14 or less, or a plurality of structures selected from these structures bonded in a chain or branched manner. Examples include monovalent groups having the following structure. When a plurality of aromatic hydrocarbon rings are connected, a structure in which 2 to 8 aromatic hydrocarbon rings are connected is usually used, and a structure in which 2 to 5 aromatic hydrocarbon rings are connected is preferable. When a plurality of aromatic hydrocarbon rings are connected, the same structure may be connected, or different structures may be connected.

Ar ⁶¹¹ and Ar ⁶¹² are preferably each independently a phenyl group,
A monovalent group in which multiple benzene rings are bonded in a multi-chain or branched manner,
A monovalent group in which one or more benzene rings and at least one naphthalene ring are bonded in a chain or branched manner,
A monovalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a chain or branched manner, or
A monovalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a chain or branched manner, and more preferably a monovalent group in which a plurality of benzene rings are bonded in a chain or in a branched manner. It is a valent group, and in any case, the order of bonding does not matter.
It is particularly preferable that Ar ⁶¹¹ and Ar ⁶¹² are each independently a monovalent group in which a plurality of benzene rings which may have substituents are bonded in a chain or branched manner; Most preferably, it is a monovalent group in which multiple rings are bonded in a chain or branched manner.

As mentioned above, the number of bonded benzene rings, naphthalene rings, phenanthrene rings and tetraphenylene rings is usually 2 to 8, preferably 2 to 5. Among these, preferred are monovalent structures in which 1 to 4 benzene rings are connected, monovalent structures in which 1 to 4 benzene rings and naphthalene rings are connected, and monovalent structures in which 1 to 4 benzene rings and phenanthrene rings are connected. It is a monovalent structure, or a monovalent structure in which 1 to 4 benzene rings and tetraphenylene rings are connected.

These aromatic hydrocarbon groups may have a substituent. The substituents that the aromatic hydrocarbon group may have are as described above, and specifically, they can be selected from the substituent group Z2. Preferred substituents are the preferred substituents of the substituent group Z2.

At least one of Ar ⁶¹¹ and Ar ⁶¹² preferably has a partial structure selected from the following formulas (11) to (13) and (21) to (24) from the viewpoint of solubility and durability of the compound, It is further preferred that Ar ⁶¹¹ and Ar ⁶¹² each independently have a partial structure selected from the following formulas (11) to (13) and (21) to (24).

In each of the above formulas (11) to (13) and (21) to (24), * represents a bonding position with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bond with an adjacent structure. Represents a position. In the following description, the definition of * is the same unless otherwise specified.

More preferably, Ar ⁶¹¹ and Ar ⁶¹² each independently have a partial structure represented by formula (11) or a partial structure represented by formula (12).
More preferably, Ar ⁶¹¹ and Ar ⁶¹² each independently have a partial structure represented by formula (11) and a partial structure represented by (12).

As a partial structure having a partial structure represented by formula (11) and a partial structure represented by formula (12), from the partial structure represented by formula (11) and the partial structure represented by formula (12), A partial structure selected from the following formulas (14) to (17), which is a structure containing a plurality of selected structures, is preferable. That is, it is preferable that Ar ⁶¹¹ and Ar ⁶¹² each independently have a partial structure selected from the above formulas (11) to (13) and the following formulas (14) to (17).

More preferably, at least one of Ar ⁶¹¹ and Ar ⁶¹² has at least a partial structure represented by formula (14) or a partial structure represented by formula (15). More preferably, Ar ⁶¹¹ and Ar ⁶¹² have a partial structure represented by formula (14) or a partial structure represented by formula (15).

At least one of Ar ⁶¹¹ and Ar ⁶¹² is a partial structure represented by the following formula (19) or a partial structure represented by the following formula (20) as a partial structure including the partial structure represented by the formula (13). It is more preferable to have the following.

In each of the above formulas (14) to (20), * represents a bonding position with an adjacent structure or a hydrogen atom. At least one of the two * represents a bonding position with an adjacent structure.

Ar ⁶¹¹ and Ar ⁶¹² each independently represent the partial structure represented by formula (11), the partial structure represented by formula (12-3), the partial structure represented by formula (14-3), or the formula ( It is preferable to have a partial structure represented by 15-3).

<R ⁶¹¹ , R ⁶¹² >
R ⁶¹¹ and R ⁶¹² each independently represent a deuterium atom, a halogen atom such as a fluorine atom, or a monovalent aromatic hydrocarbon having 6 to 50 carbon atoms which may have a substituent.
Preferably, it is a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.
Examples of the aromatic hydrocarbon group include monovalent groups having an aromatic hydrocarbon structure, more preferably having 6 to 30 carbon atoms, still more preferably 6 to 18 carbon atoms, particularly preferably 6 to 10 carbon atoms.
The monovalent aromatic hydrocarbon group is specifically the same as Ar ⁶¹¹ above, and the preferred aromatic hydrocarbon group is also the same, with phenyl group being particularly preferred.
These aromatic hydrocarbon groups may have a substituent. The substituents that the aromatic hydrocarbon group may have are as described above, and specifically, they can be selected from the substituent group Z2. Preferred substituents are the preferred substituents of the substituent group Z2.

<n ⁶¹¹ , n ⁶¹² >
n ⁶¹¹ and n ⁶¹² are each independently an integer of 0 to 4. Preferably it is 0 to 2, more preferably 0 or 1.
When Ar ⁶¹¹ is an unsubstituted phenyl group, n ⁶¹¹ is an integer of 1 to 4, and when Ar ⁶¹² is an unsubstituted phenyl group, n ⁶¹² is an integer of 1 to 4. Preferable from the viewpoint of solubility.

<Substituent>
When Ar ⁶¹¹ , Ar ⁶¹² , R ⁶¹¹ , and R ⁶¹² are monovalent aromatic hydrocarbon groups, the substituents they may have are preferably selected from the substituent group Z2.

<G>
G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.

The number of carbon atoms in the aromatic hydrocarbon group of G is preferably 6 to 50, more preferably 6 to 30, and even more preferably 6 to 18. Specifically, the aromatic hydrocarbon group usually has 6 carbon atoms, such as a benzene ring, a naphthalene ring, an anthracene ring, a tetraphenylene ring, a phenanthrene ring, a chrysene ring, a pyrene ring, a benzanthracene ring, or a perylene ring. A divalent group having an aromatic hydrocarbon structure, usually 30 or less, preferably 18 or less, more preferably 14 or less, or a plurality of structures selected from these structures bonded in a chain or branched manner. Examples include divalent groups having the following structure. When a plurality of aromatic hydrocarbon rings are connected, a structure in which 2 to 8 aromatic hydrocarbon rings are connected is usually used, and a structure in which 2 to 5 aromatic hydrocarbon rings are connected is preferable. When a plurality of aromatic hydrocarbon rings are connected, the same structure may be connected, or different structures may be connected.

G is preferably a single bond, a phenylene group, a divalent group in which a plurality of benzene rings are bonded in a chain or branched manner, or a chain or branched group in which one or more benzene rings and at least one naphthalene ring are bonded together. A divalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a chain or branched manner, or
A divalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a chain or branched manner, and more preferably a divalent group in which a plurality of benzene rings are bonded in a chain or branched manner. It is a valent group, and the order of bonding does not matter in either case.

As mentioned above, the number of bonded benzene rings, naphthalene rings, phenanthrene rings and tetraphenylene rings is usually 2 to 8, preferably 2 to 5. More preferred among these are a divalent structure in which 1 to 4 benzene rings are connected, a divalent structure in which 1 to 4 benzene rings and a naphthalene ring are connected, and a divalent structure in which 1 to 4 benzene rings and a phenanthrene ring are connected. It is a divalent structure, or a divalent structure in which 1 to 4 benzene rings and a tetraphenylene ring are connected.

<Molecular weight>
The compound represented by the formula (240) is a low-molecular material, and the molecular weight is preferably 3,000 or less, more preferably 2,500 or less, still more preferably 2,000 or less, and particularly preferably 1 , 500 or less, usually 400 or more, preferably 500 or more, more preferably 600 or more.

<Specific example of compound IV represented by the above formula (240)>
Preferred specific examples of compound IV represented by formula (240) are shown below, but the present invention is not limited thereto.

The light-emitting layer and composition of the organic electroluminescent device of the present invention may contain only one type of compound represented by the formula (240), or may contain two or more types. .

(Ar ⁶¹ , Ar ⁶² , Ar ⁶⁵ )
Ar ⁶¹ , Ar ⁶² and Ar ⁶⁵ in formula (260) are each independently a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms which may have a substituent.

From the viewpoint of solubility and durability of the compound, Ar ⁶¹ , Ar ⁶² and Ar ⁶⁵ in formula (260) are a hydrogen atom, a monovalent group of a benzene ring, a monovalent group of a naphthalene ring, formula (261) or A structure represented by formula (262) is preferred, a hydrogen atom, a monovalent group of a benzene ring, a structure represented by formula (261) or formula (262) is more preferred, and a hydrogen atom, a monovalent group of a benzene ring A structure represented by the formula (262) is more preferable, and a structure represented by the formula (262) is particularly preferable.
From the viewpoint of durability and charge transportability, one or more and three or less groups of Ar ⁶¹ , Ar ⁶² , and at least one Ar ⁶⁵ are the following formula (261) or the following formula (262). is preferable, and it is more preferable that one or more and three or less of Ar ⁶¹ , Ar ⁶² , and at least one group and Ar ⁶⁵ have the following formula (262).
From the viewpoint of charge transportability and solubility, it is preferable that one group among Ar ⁶¹ , Ar ⁶² , and at least one Ar ⁶⁵ is represented by the following formula (262).
From the viewpoint of durability, it is preferable that two or more groups among Ar ⁶¹ , Ar ⁶² , and at least one Ar ⁶⁵ are represented by the following formula (262), and three groups are represented by the following formula (262). It is more preferable that the

(Formula (261), Formula (262))

When Ar ⁶¹ is formula (261) or formula (262), m1 is preferably 0 or 1, and more preferably 0. When Ar ⁶² is formula (261) or formula (262), m2 is preferably 0 or 1, more preferably 0. When Ar ⁶⁵ is formula (261) or formula (262), m5 is preferably 0 or 1, and more preferably 0.

(Ar ⁶³ , Ar ⁶⁴ )
Ar ⁶³ and Ar ⁶⁴ in formula (260) each independently represent a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms that may have a substituent.

Examples of monovalent aromatic hydrocarbon groups having 6 or more and 60 or less carbon atoms include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetraphenylene ring, chrysene ring, pyrene ring, benzanthracene ring, perylene ring, A monovalent group of a biphenyl ring or a terphenyl ring can be mentioned.

From the viewpoint of solubility and durability of the compound, Ar ⁶³ and Ar ⁶⁴ in formula (260) are each independently preferably a hydrogen atom, a monovalent group of a benzene ring, or a monovalent group of a naphthalene ring; , a monovalent group having a benzene ring is more preferable.

(L ¹ to L ⁵ )
In formula (260), L ¹ to L ⁵ each independently represent a divalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms that may have a substituent.

Examples of divalent aromatic hydrocarbon groups having 6 or more and 60 or less carbon atoms include benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, or perylene ring. Examples include divalent groups.
L ¹ to L ⁵ each independently optionally have a substituent, and is preferably a phenylene group or a divalent group in which two or more phenylene groups, for example, 2 to 5 phenylene groups, are connected by direct bonds; From the viewpoint of solubility, it is more preferable to use a 1,3-phenylene group which may be present.

( ^R60 )
Each R ⁶⁰ in formula (260) independently represents a substituent. As the substituent, those selected from the above-mentioned substituent group Z2 can be used. Among them, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, silyl groups, siloxy groups, aralkyl groups, or aromatic Group hydrocarbon groups are preferred. From the viewpoint of heat resistance and durability, alkyl groups, alkenyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, silyl groups, siloxy groups, aralkyl groups, aromatic hydrocarbon groups is preferred, an alkyl group, an alkoxy group, an aralkyl group, and an aromatic hydrocarbon group are more preferred, and an alkyl group having 10 or less carbon atoms, an aralkyl group having 30 or less carbon atoms, and an aromatic hydrocarbon group having 30 or less carbon atoms are more preferred. , a benzene ring or a group in which 2 to 5 benzene rings are connected are particularly preferred.

(m1-m5)
m1, m2 and m5 in formula (260) each independently represent an integer from 0 to 5,
m3 and m4 each independently represent an integer of 1 to 5.

m1, m2, and m5 in formula (260) are preferably 4 or less, more preferably 3 or less, even more preferably 2 or less, particularly preferably 1 or less, and most preferably 0, from the viewpoint of compound solubility and durability. preferable.
Also, m1 when Ar ⁶¹ is formula (261) or formula (262), m2 when Ar ⁶² is formula (261) or formula (262), and Ar ⁶⁵ is formula (261) or formula ( 262), m5 is preferably 0.

From the viewpoint of solubility and durability of the compound, m3 and m4 in formula (260) are preferably 1 or more, preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less.

When m1 in formula (260) is 2 or more, the plurality of ^L1s may be the same or different. When m2 in formula (260) is 2 or more, the plurality of ^L2 may be the same or different. When m3 in formula (260) is 2 or more, the plurality of ^L3s may be the same or different. When m4 in formula (260) is 2 or more, the plurality of ^L4s may be the same or different. When m5 in formula (260) is 2 or more, the plurality of ^L5s may be the same or different.

((L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , (L ⁵ ) _m5 )
At least one group among (L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , and at least one (L ⁵ ) _m5 in formula (260) is From the viewpoint of performance and durability, a partial structure selected from a partial structure represented by the following formula (11), a partial structure represented by the following formula (12), and a partial structure represented by the following formula (13). (L ¹ ) _m1 when m1 is 1 or more, (L ² ) _m2 when m2 is 1 or more, and (L ⁵ ) m5 when n is 1 or more and _m5 is 1 or more, and (L ³ ) _m3 when m3 is 1 or more and (L ⁴ ) _m4 when m4 is 1 or more are a partial structure represented by the following formula (11), a part represented by the following formula (12) It is further preferable to have a partial structure selected from the following structure and a partial structure represented by the following formula (13). As a preferable embodiment, for example, in formula (260), (L ¹ ) _m1 when m1 is 1 or more, (L ² ) m2 when _m2 is 1 or more, and (L ³ ) when m3 is 1 or more. (L ⁴ ) when _m3 and _m4 are 1 or more, and (L ⁵ ) _{m5 when n is 1 or more and m5} is 1 or more are each independently expressed by the following formulas (11) to (17). It is possible to have a partial structure selected from among the partial structures.

In each of the above formulas (11) to (13), * represents a bonding position with an adjacent structure or a hydrogen atom when Ar ⁶¹ , Ar ⁶² , Ar ⁶³ , Ar ⁶⁴ or Ar ⁶⁵ is a hydrogen atom, and 2 At least one of the two * represents a bonding position with an adjacent structure. In the following description, the definition of * is the same unless otherwise specified.

More preferably, at least one group among (L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , and at least one (L ⁵ ) _m5 in formula (260) is , has a partial structure represented by formula (11) or a partial structure represented by formula (12).
More preferably, in formula (260), (L ¹ ) _m1 when m1 is 1 or more, (L ² ) _m2 when m2 is 1 or more, and (L ³ ) m3, _m4 when m3 is 1 or more. (L ⁴ ) _m4 when is 1 or more, and (L ⁵ ) m5 when n is 1 or more and _m5 is 1 or more, respectively, have a partial structure represented by formula (11) or formula (12). It has a partial structure.
Particularly preferably, in formula (260), (L ¹ ) _m1 when m1 is 1 or more, (L ² ) _m2 when m2 is 1 or more, and (L ³ ) m3, _m4 when m3 is 1 or more. (L ⁴ ) _m4 when n is 1 or more, and (L ⁵ ) m5 when n is 1 or more and _m5 is 1 or more, respectively, have a partial structure represented by formula (11) and a partial structure represented by formula (12). It has a partial structure.

In formula (260), formula (12) is preferably the following formula (12-2).

In formula (260), formula (12) is more preferably the following formula (12-3).

Furthermore, from the viewpoint of solubility and durability of the compound, (L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , at least one of and (L ⁵ ) in formula (260) The partial structure that at least one group of _m5 preferably has is a partial structure having a partial structure represented by formula (11) and a partial structure represented by formula (12).

In formula (260), the partial structure having the partial structure represented by formula (11) and the partial structure represented by formula (12) includes the partial structure represented by formula (11) and the partial structure represented by formula (12). A partial structure selected from the following formulas (14) to (17), which is a structure containing a plurality of structures selected from the represented partial structures, is preferable. That is, (L ¹ ) _m1 when m1 is 1 or more, (L ² ) _m2 when m2 is 1 or more, (L ³ ) _m3 when m3 is 1 or more, and (L ⁴ ) _m4 and (L ⁵ ) m5 when n is 1 or more and _m5 is 1 or more are each independently expressed by the above formula (11) to the above formula (13) and the following formula (14) to the following formula (17) It is preferable to have a partial structure selected from.

In formula (260), a structure that includes a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12) means, for example, formula (14) has the following formula (14a ), it is a partial structure that can be considered to have one partial structure represented by formula (11) and two partial structures represented by formula (12).

Further preferably, at least one of (L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , and at least one (L ⁵ ) _m5 in formula (260) The group has a partial structure represented by formula (14) or a partial structure represented by formula (15). More preferably, (L ¹ ) _m1 when m1 is 1 or more, (L 2 ) m2 when m2 is 1 or more, (L ³ ) _m3 when m3 is 1 or more, and (L ³ ) _m3 when m4 is 1 or more. (L ⁴ ) _m4 and (L ⁵ ) m5 when n is 1 or more and _m5 is 1 or more have a partial structure represented by formula (14) or a partial structure represented by formula (15) .

In formula (260), formula (14) is preferably the following formula (14-2).

In formula (260), formula (14) is more preferably the following formula (14-3).

In formula (260), formula (15) is preferably the following formula (15-2).

In formula (260), formula (15) is more preferably the following formula (15-3).

In formula (260), formula (17) is preferably the following formula (17-2).

Furthermore, at least one of (L ¹ ) _m1 , (L ² ) _m2 , (L ³ ) _m3 , (L ⁴ ) _m4 , and at least one (L ⁵ ) _m5 in formula (260) is expressed by formula (13). As the partial structure including the partial structure represented by, it is more preferable to have a partial structure represented by the following formula (19) or a partial structure represented by the following formula (20).

In each of the above formulas (14) to (20), * represents a bonding position with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position with an adjacent structure.

In formula (260), among formulas (14) to (20), formulas (14-3) and (15-3) are preferred, and formula (14-3) is more preferred.

(Preferred partial structure of L ¹ to L ⁵ )
In formula (260), L ¹ to L ⁵ are a partial structure represented by formula (11), a partial structure represented by formula (12-3), a partial structure represented by formula (14-3), or It is preferable to have a partial structure represented by formula (15-3).

(n)
n in formula (260) represents an integer from 0 to 10.
From the viewpoints of solubility and durability of the compound, n in formula (260) is preferably 1 or more, more preferably 2 or more, preferably 6 or less, even more preferably 5 or less, and particularly preferably 4 or less.

(a1-a3)
a1 to a3 each independently represent an integer of 0 to 3.
a1 to a3 are from the viewpoint of solubility and durability of the compound,
a1 to a3 are preferably each independently 0 or 1;
Most preferred is a1=a2=a3=0.

(R ¹⁰¹ to R ¹²⁶ )
In formula (260), R ¹⁰¹ to R ¹²⁶ each independently represent a hydrogen atom or a substituent. As the substituent, those selected from the above-mentioned substituent group Z2 can be used. Among them, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, silyl groups, siloxy groups, aralkyl groups, or aromatic Group hydrocarbon groups are preferred. From the viewpoint of durability, alkyl groups, alkenyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, silyl groups, siloxy groups, aralkyl groups, and aromatic hydrocarbon groups are preferable. A hydrogen atom and an aromatic hydrocarbon group are more preferred, and a hydrogen atom is particularly preferred.

(substituent)
In formula (260), a monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms in Ar ⁶¹ to Ar ⁶⁵ , and a divalent aromatic hydrocarbon group having 6 to 60 carbon atoms in L ¹ to L ⁵ ; The substituents that the hydrocarbon group may have can each be independently selected from the substituent group Z2. Among them, alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, silyl groups, siloxy groups, aralkyl groups, or aromatic Group hydrocarbon groups are preferred, and alkyl groups, alkenyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, silyl groups, siloxy groups, aralkyl groups, and aromatic hydrocarbon groups are more preferred. .

(molecular weight)
The molecular weight of the compound represented by formula (260) is preferably 3,000 or less, more preferably 2,500 or less, even more preferably 2,000 or less, particularly preferably 1,500 or less, It is usually 400 or more, preferably 500 or more, more preferably 600 or more.

(Concrete example)
Specific examples of the compound represented by formula (260) are shown below, but the compound is not limited thereto.

The light-emitting layer and composition of the organic electroluminescent device of the present invention may contain only one type of compound represented by the formula (260), or may contain two or more types. .

[Composition]
The composition of the present invention is a composition containing the material for the light emitting layer of the organic electroluminescent device of the present invention and an organic solvent. That is, the composition of the present invention is a composition for forming a light emitting layer of an organic electroluminescent device, which contains the light emitting compound, the organometallic compound, and an organic material.

More specifically, the composition according to the first embodiment of the present invention is a composition containing a material for a light emitting layer of an organic electroluminescent device according to the first embodiment of the present invention, and an organic solvent. That is, the composition according to the first embodiment of the present invention is a composition for forming a light-emitting layer of an organic electroluminescent device, and comprises a light-emitting compound represented by the formula (1) above, and a molecular weight of 1,200 or more. It contains a certain organometallic compound and an organic material, and the light-emitting compound and the organometallic compound satisfy the relational expression (E-1).

Preferred embodiments of the luminescent compound represented by formula (1) and the organometallic compound contained in the composition according to the first embodiment of the present invention are as described above. The composition according to the first embodiment of the present invention is preferably a composition for forming a light emitting layer.

Further, in more detail, the composition according to the second embodiment of the present invention is a composition containing a material for a light emitting layer of an organic electroluminescent device according to the second embodiment of the present invention, and an organic solvent. . That is, the composition according to the second embodiment of the present invention is a composition for forming a light emitting layer of an organic electroluminescent device, and comprises a light emitting compound represented by the above formula (1) and a light emitting compound represented by the above formula (201). The light-emitting compound and the organometallic compound satisfy the relational formula (E-1), and the host material contains a compound represented by the formula (250), a host material, and an organic solvent. It contains at least one selected from the compound represented by formula (240) and the compound represented by formula (260).

The luminescent compound represented by the above formula (1), the organometallic compound represented by the above formula (201), and the compound represented by the above formula (250) contained in the composition according to the second embodiment of the present invention , the compound represented by the formula (240), and the compound represented by the formula (260) are as described above. The composition according to the second embodiment of the present invention is preferably a composition for forming a light emitting layer.

The method for forming the light emitting layer may be either a vacuum evaporation method or a wet film forming method, but preferably a wet film forming method. In the case of the wet film forming method, the light emitting layer is formed by applying a light emitting layer forming composition containing an organic solvent and drying it.

The composition according to the first embodiment of the present invention preferably further includes the host material. The composition is a composition in which a polycyclic heterocyclic compound represented by the above formula (1) and an organometallic compound represented by the above formula (201) are dissolved or dispersed in an organic solvent. The composition is a composition in which the polycyclic heterocyclic compound represented by the above formula (1), the organometallic compound represented by the above formula (201), and the host material are dissolved or dispersed in an organic solvent. It's fine.

(Organic solvent)
The organic solvent contained in the composition is a volatile liquid component used to form a layer containing a polycyclic heterocyclic compound by wet film formation.

The organic solvent is not particularly limited as long as it is an organic solvent in which the polycyclic heterocyclic compound and the charge transporting compound as the solute can be well dissolved.

Preferred organic solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, tetralin, and methylnaphthalene; Halogenated aromatic hydrocarbons such as chlorobenzene and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3 - Aromatic ethers such as dimethylanisole, 2,4-dimethylanisole, diphenyl ether; Aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate; Alicyclic ketones such as cyclohexanone, cyclooctanone, and fenchone; Alicyclic alcohols such as cyclohexanol and cyclooctanol; Aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Aliphatic alcohols such as butanol and hexanol; Ethylene Examples include aliphatic ethers such as glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA).

Among these, from the viewpoint of viscosity and boiling point, alkanes, aromatic hydrocarbons, and aromatic esters are preferred, and aromatic hydrocarbons and aromatic esters are particularly preferred.

One type of these organic solvents may be used alone, or two or more types may be used in any combination and ratio.

The boiling point of the organic solvent used is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and usually 350°C or lower, preferably 330°C or lower, more preferably 300°C or lower. If the boiling point of the organic solvent is below this range, the stability of film formation may decrease due to evaporation of the solvent from the composition during wet film formation. If the boiling point of the organic solvent exceeds this range, during wet film formation, the stability of film formation may decrease due to residual solvent after film formation.

It is particularly preferable to combine two or more organic solvents with a boiling point of 150° C. or higher among the above organic solvents, because it is thought that it is easier to form a more uniform coating film.

(Content)
The content of the polycyclic heterocyclic compound represented by formula (1) in the composition is usually 0.001% by mass or more, preferably 0.01% by mass or more, and usually 30.0% by mass or less, preferably 20.0% by mass or more. It is 0% by mass or less. The content of the organometallic compound represented by formula (201) in the composition is usually 0.001% by mass or more, preferably 0.01% by mass or more, and usually 30.0% by mass or less, preferably 20.0% by mass. % or less. By setting the content within this range, holes and electrons can be efficiently injected from the adjacent layer (for example, a hole transport layer or a hole blocking layer) to the light emitting layer, and the driving voltage can be reduced. Can be done. In addition, the polycyclic heterocyclic compound represented by formula (1) and the organometallic compound represented by formula (201) may be contained in the composition alone, or two or more types may be contained in a combination. May be included.
The content of the organometallic compound represented by formula (2) contained in the composition is usually 100 parts by mass or less, preferably 10 parts by mass, per 1 part by mass of the polycyclic heterocyclic compound represented by formula (1). It is not more than 5 parts by mass, more preferably not more than 5 parts by mass, usually not less than 0.01 parts by mass, preferably not less than 0.1 parts by mass, and even more preferably not less than 0.2 parts by mass.

When the composition contains a host material, the content of the host material is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 30.0% by mass or less, preferably 20.0% by mass or less. be.

The content of the host material contained in the composition is usually 1000 parts by mass or less, preferably 100 parts by mass or less, and more preferably 50 parts by mass or less, per 1 part by mass of the organometallic compound represented by formula (201). The amount is usually 0.01 part by mass or more, preferably 0.1 part by mass or more, and more preferably 1 part by mass or more.

The content of the organic solvent contained in the composition is usually 10% by mass or more, preferably 50% by mass or more, particularly preferably 80% by mass or more, and usually 99.95% by mass or less, preferably 99.9% by mass or less. , particularly preferably 99.8% by mass or less. If the content of the organic solvent is at least the above-mentioned lower limit, it will have a suitable viscosity and the coating properties will be improved, and if it is below the above-mentioned upper limit, a uniform film will be easily obtained and the film-forming property will be good.

(Other ingredients)
The composition may further contain other compounds in addition to the above-mentioned compounds, if necessary. Preferred examples of other compounds include dibutylhydroxytoluene, which is known as an antioxidant, and phenols such as dibutylphenol.

(Film forming method)
The method for forming the light emitting layer is preferably a wet film forming method. The wet film forming method is a method in which a composition is applied to form a liquid film, and the organic solvent is removed by drying to form a light emitting layer film. Examples of coating methods include spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet, nozzle printing, screen printing, and gravure. A wet film forming method such as a printing method or a flexo printing method is employed, and the coating film is dried to form a film. Among these coating methods, spin coating, spray coating, inkjet, nozzle printing, and the like are preferred. When manufacturing an organic EL display device equipped with an organic electroluminescent element, an inkjet method or a nozzle printing method is preferred, and an inkjet method is particularly preferred.

The drying method is not particularly limited, but natural drying, vacuum drying, heat drying, or vacuum drying while heating can be used as appropriate. Heat drying may be carried out after natural drying or reduced pressure drying in order to further remove residual organic solvent.

In the vacuum drying, it is preferable to reduce the pressure to below the vapor pressure of the organic solvent contained in the composition.

When heating, the heating method is not particularly limited, but heating with a hot plate, heating in an oven, infrared heating, etc. can be used. The heating time is usually 80°C or higher, preferably 100°C or higher, more preferably 110°C or higher, preferably 200°C or lower, and even more preferably 150°C or lower.

The heating time is usually 1 minute or more, preferably 2 minutes or more, usually 60 minutes or less, preferably 30 minutes or less, and more preferably 20 minutes or less.

[Hole injection layer]
The organic electroluminescent device according to the present invention preferably has a hole injection layer on the anode. A hole injection layer is typically formed on and in contact with the anode.
The hole injection layer contains a hole transport material because it needs to have a function of transporting holes. Furthermore, it is preferable that the hole injection layer contains tetraarylborate ions. Moreover, it is also preferable to include a crosslinked product of an electron-accepting compound having a crosslinking group.

In order to improve the hole injection property from the anode to the hole injection layer and to improve the hole transport property within the hole injection layer, the hole transport material contained in the hole injection layer must have a cation radical moiety. It is preferable to include. In order to convert the hole transport material into cation radicals, an electron-accepting compound is used when forming the hole injection layer. As the parent skeleton of the electron-accepting compound, an ionic compound consisting of a tetraarylborate ion, which is an anion with an ionic valence of 1, and a counter cation, which will be described later, is preferred because it has high stability.

Cation radicalization of the hole transport material is performed as follows. For example, when a compound having a triarylamine structure is used as a hole-transporting material, and a tetraarylborate with diaryliodonium as a countercation is used as an electron-accepting compound, when forming a hole-injecting layer, the following formula is obtained: The countercation can be changed from diaryliodonium to triarylaminium.

(For example, Ar, Ar ¹ to Ar ⁴ are each independently an aromatic hydrocarbon group that may have a substituent, an aromatic heterocyclic group that may have a substituent, or an aromatic heterocyclic group that may have a substituent) (It is a monovalent group in which a plurality of structures selected from an aromatic hydrocarbon ring group that may have a substituent and an aromatic heterocyclic group that may have a substituent are connected.)

Since the triarylaminium produced in the above reaction has a half-occupied orbital (SOMO) that can accept electrons, the tetraarylborate with triarylaminium as a counter cation is an electron-accepting compound. .

In the present invention, a compound consisting of a cation and a tetraarylborate ion, which is an anion, of this hole transporting material is referred to as a charge transporting ionic compound. Details will be described later.

[Electron-accepting compound having a crosslinking group]
Examples of electron-accepting compounds include those having an ionic compound consisting of a tetraarylborate ion and a counter cation as a parent skeleton as described above, or those having an ionic compound consisting of a tetraarylborate ion and a counter cation as a parent skeleton, and the following: Examples include those having a crosslinking group.

(crosslinking group)
The crosslinking group of the electron-accepting compound that forms the crosslinked product of the electron-accepting compound having a crosslinking group, which may be included in the hole injection layer of the organic electroluminescent device according to the present invention, refers to A group that reacts with other groups located near the crosslinking group to form a new chemical bond when irradiated with energy rays. In this case, the reactive group may be the same group as the crosslinking group or a different group.

When the electron-accepting compound contains a cross-linking group, a cross-linking reaction progresses when forming the hole-injection layer, and the electron-accepting compound can be fixed to the hole-injection layer. It is considered that when the layer is formed by a wet film formation method, the electron-accepting compound does not diffuse into the layer above the hole-injection layer. Therefore, it is presumed that by using an electron-accepting compound having a crosslinking group, it is possible to suppress the deterioration reaction during driving.

As the crosslinking group, a crosslinking group represented by any of the following formulas (X1) to (X18) is preferable.

(In the formulas (X1) to (X4), the benzene ring and the naphthalene ring may have a substituent. Furthermore, the substituents may be bonded to each other to form a ring.
R ^X in formula (X4), formula (X5), formula (X6) and formula (X10) each independently represents an alkyl group which may have a substituent. )

The alkyl group represented by R ^X has a linear, branched or cyclic structure, and has 1 or more carbon atoms, preferably 24 or less, more preferably 12 or less, and even more preferably 8 or less.

The benzene ring and naphthalene ring of formulas (X1) to (X4), and the substituent that ^R group, alkyloxy group, and aralkyl group.

The alkyl group as a substituent has a linear, branched or cyclic structure, and the number of carbon atoms is preferably 24 or less, more preferably 12 or less, still more preferably 8 or less, and preferably 1 or more.

The number of carbon atoms in the aromatic hydrocarbon group as a substituent is preferably 24 or less, more preferably 18 or less, even more preferably 12 or less, and preferably 6 or more. The aromatic hydrocarbon group may further have the above alkyl group as a substituent.

The number of carbon atoms in the alkyloxy group as a substituent is preferably 24 or less, more preferably 12 or less, even more preferably 8 or less, and preferably 1 or more.

The number of carbon atoms in the aralkyl group as a substituent is preferably 30 or less, more preferably 24 or less, even more preferably 14 or less, and preferably 7 or more. The alkylene group contained in the aralkyl group preferably has a linear or branched structure. The aryl group contained in the aralkyl group may further have the above-mentioned alkyl group as a substituent.

As the crosslinking group, a crosslinking group represented by any one of formulas (X1) to (X3) is preferable because the crosslinking reaction proceeds only with heat, has low polarity, and has little effect on charge transport.

In the crosslinking group represented by formula (X1), the cyclobutene ring is opened by heat, and the ring-opened groups bond together to form a crosslinked structure, as shown in the following formula.

In the crosslinking group represented by formula (X2), the cyclobutene ring is opened by heat, and the ring-opened groups bond together to form a crosslinked structure, as shown in the following formula.

In the crosslinking group represented by formula (X3), the cyclobutene ring is opened by heat, and the ring-opened groups bond together to form a crosslinked structure, as shown in the following formula.

In the crosslinking group represented by any of formulas (X1) to (X3), the cyclobutene ring is opened by heat, and the opened group reacts with the double bond if there is a double bond nearby. to form a crosslinked structure. An example will be shown below in which a crosslinking group represented by formula (X1) forms a ring-opened group and a crosslinking group represented by formula (X4) having a double bond site forms a crosslinked structure. (However, ^RX in formula (X4) is not shown.)

In addition to the crosslinking group represented by formula (X4), examples of the group containing a double bond that can react with the crosslinking group represented by any of formulas (X1) to (X3) include formula (X5), Examples include crosslinking groups represented by any one of (X6), (X12), (X15), (X16), (X17), and (X18). When a group containing these double bonds is used as a crosslinking group in an electron-accepting compound, any of the formulas (X1) to (X3) may be added to other components forming the hole-injecting layer such as a hole-transporting compound. It is preferable to include a crosslinking group represented by the above because the possibility of forming a crosslinked structure increases.

As the crosslinking group, a radically polymerizable crosslinking group represented by any one of formulas (X4), (X5), and (X6) is preferable because it has low polarity and is unlikely to interfere with charge transport.

As the crosslinking group, a crosslinking group represented by formula (X7) is preferable in terms of improving electron accepting property. Note that when the crosslinking group represented by formula (X7) is used, the following crosslinking reaction proceeds.

A crosslinking group represented by either formula (X8) or (X9) is preferred in terms of high reactivity. Note that when the crosslinking group represented by formula (X8) and the crosslinking group represented by formula (X9) are used, the following crosslinking reaction proceeds.

As the crosslinking group, a cationically polymerizable crosslinking group represented by any one of formulas (X10), (X11), and (X12) is preferred in terms of high reactivity.

(Crosslinked product of electron-accepting compound)
As described later, the hole injection layer of the organic electroluminescent device of the present invention is preferably obtained by wet film formation of a composition for forming a hole injection layer, and the composition for forming a hole injection layer is preferably obtained by forming a film using a composition as described below. It is preferable that the composition be obtained through a step of dissolving or dispersing a first ionic compound having a tetraarylborate ion structure and a hole transporting material described below in an organic solvent. The hole transport layer of the organic electroluminescent device of the present invention contains a charge transporting ionic compound having the tetraarylborate ion structure of the present invention described below as an anion and the cation of the hole transport material as a counter cation. It is preferable.

Therefore, as the electron-accepting compound in the electron-accepting compound having a crosslinking group, an electron-accepting compound that is an ionic compound is preferable, and the ionic compound as the electron-accepting compound is an ionic compound having a tetraarylborate ion structure as an anion. is preferred. When the electron-accepting compound is an ionic compound having a tetraarylborate ion structure as an anion, it is preferable that the tetraarylborate ion has a crosslinking group. The structure of the tetraarylborate ion will be described later.

When an electron-accepting compound having a crosslinking group is used, a crosslinked product of the electron-accepting compound having a crosslinking group is formed. The crosslinked product of the electron-accepting compound having a crosslinking group includes the following crosslinked products.
・A compound in which electron-accepting compounds are crosslinked.
- A compound in which an electron-accepting compound and a hole-transporting material are crosslinked.
- A compound in which an electron-accepting compound and a tetraarylborate ion in the present invention are crosslinked.
- A compound in the present invention in which tetraarylborate ions are crosslinked with each other.
- A compound in which a tetraarylborate ion and a hole transport material in the present invention are crosslinked.

Here, "tetraarylborate ion in the present invention" refers to the case where it exists as an electron-accepting compound which is an ionic compound consisting of a tetraarylborate ion and a counter cation described below, and the tetraarylborate ion described below. and a cation of a hole transporting material.

The two crosslinking groups that undergo a crosslinking reaction may be the same crosslinking group or different crosslinking groups as long as the crosslinking reaction is possible.

[Tetraarylborate ion]
The tetraarylborate ion is an aromatic hydrocarbon ring which may have four substituents and/or a crosslinking group, or an aromatic hydrocarbon ring which may have a substituent and/or a crosslinking group on the boron atom. It is an anion with an ionic valence of 1 substituted with a heterocycle.

A polycyclic heterocyclic compound containing boron has an empty p-orbital on boron, and is particularly likely to react with electron-donating substances. As a result of the reaction, an oxide of the electron-donating substance is generated, and this oxide may cause further deterioration reactions during operation. On the other hand, the tetraarylborate ion, which has a stable structure that satisfies the octet rule and does not have an empty p orbital on boron, has the effect of stabilizing a cation obtained by oxidizing an electron-donating substance. Therefore, it is estimated that by using tetraarylborate ions, deterioration reactions during driving can be suppressed, durability is improved, and the driving life of the element is extended.

The tetraarylborate ion that can be included in the organic electroluminescent device of the present invention preferably has a fluorine atom or a fluorine-substituted alkyl group as a substituent for the aryl group, since stability is further improved. That is, it is preferably represented by the following formula (112).

(In formula (112),
Ar ¹ , Ar ² , Ar ³ and Ar ⁴ each independently have an aromatic hydrocarbon ring group which may have a substituent and/or a crosslinking group, a substituent and/or a crosslinking group. an aromatic heterocyclic group that may have a substituent and/or a crosslinking group; an aromatic hydrocarbon ring group that may have a substituent and/or a crosslinking group; represents a monovalent group in which multiple structures selected from are connected,
At least one of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ has a fluorine atom or a fluorine-substituted alkyl group as a substituent. )

It is preferable that at least one of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ has a crosslinking group.

The aromatic hydrocarbon ring group used for Ar ¹ , Ar ² , Ar ³ and Ar ⁴ is preferably a monocyclic ring or 2 to 6 condensed rings. Specifically, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, biphenyl structure, terphenyl structure. , or a quaterphenyl structure.

The aromatic heterocyclic group used for Ar ¹ , Ar ² , Ar ³ and Ar ⁴ is preferably a monocyclic ring or 2 to 6 condensed rings. Specifically, furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benziisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring.

Among these, a monovalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring or a biphenyl group are more preferable because they have excellent stability and heat resistance. Particularly preferred is a monovalent group derived from a benzene ring, ie, a phenyl group or a biphenyl group.

1 in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a substituent and/or a crosslinking group and an aromatic heterocyclic group which may have a substituent and/or a crosslinking group are connected. The total number of monocyclic or 2 to 6 fused ring aromatic hydrocarbon ring groups and monocyclic or 2 to 6 fused ring aromatic heterocyclic groups contained in the valent group is 2 or more and 8 or less. is preferable, 4 or less is more preferable, and 3 or less is more preferable.

Examples of the substituents that Ar ¹ , Ar ² , Ar ³ and Ar ⁴ may have include groups described in substituent group W described below.

As the substituent for Ar ¹ , Ar ² , Ar ³ and Ar ⁴ , a fluorine atom or a fluorine-substituted alkyl group is preferable from the viewpoint of increasing the stability of the anion and improving the effect of stabilizing the cation. Further, the fluorine atom or the fluorine-substituted alkyl group is preferably substituted with two or more of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ , and more preferably with three or more. Preferably, four substitutions are most preferable.

The fluorine-substituted alkyl group as a substituent for Ar ¹ , Ar ² , Ar ³ and Ar ⁴ is a linear or branched alkyl group having 1 to 12 carbon atoms and substituted with a fluorine atom. Preferably, a perfluoroalkyl group is more preferable, a linear or branched perfluoroalkyl group having 1 to 5 carbon atoms is even more preferable, a linear or branched perfluoroalkyl group having 1 to 3 carbon atoms is particularly preferable, and a perfluoroalkyl group is particularly preferable. Most preferred is a methyl group. The reason for this is that the hole injection layer containing a crosslinked product of an electron-accepting compound having a tetraarylborate ion or a crosslinking group and the coating film laminated thereon become stable.

The crosslinking groups that Ar ¹ , Ar ² , Ar ³ and Ar ⁴ may have are as described above.

The tetraarylborate ion that can be included in the organic electroluminescent device of the present invention further increases the stability of the anion and further improves the effect of stabilizing the ^cation ^. , Ar ³ and Ar ⁴ are preferably groups represented by formula (113), and at least two of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are each independently represented by formula (113). It is more preferable that at least three of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are each independently a group represented by formula (113), and Ar ¹ , Ar ² , Ar Most preferably, all of ³ and Ar ⁴ are each independently a group represented by formula (113).

(In formula (113),
R ^A each independently represents an aromatic hydrocarbon ring group which may have a substituent and/or a crosslinking group, an aromatic heterocyclic group which may have a substituent and/or a crosslinking group, a substituted A monovalent structure in which a plurality of structures selected from an aromatic hydrocarbon ring group which may have a group and/or a crosslinking group, and an aromatic heterocyclic group which may have a substituent and/or a crosslinking group are connected. is a group, a fluorine-substituted alkyl group, a substituent or a crosslinking group,
F ₄ represents substitution of 4 fluorine atoms,
F _(5-m) represents that 5-m fluorine atoms are independently substituted,
k each independently represents an integer from 0 to 5,
Each m independently represents an integer of 0 to 5. )

k is preferably 1 or more, more preferably 2 or more in terms of further improving the stability of the anion. k is preferably 0 or 1, and preferably 0, from the viewpoint of easy dispersion without bias.

m is preferably 0 in terms of superior durability, preferably 1 or more in terms of being able to introduce various functions to the tetraarylborate ion, and more preferably 1 or 2 in terms of being compatible with durability.
It is preferable that k+m≧1 because the stability of the anion is improved and the durability is also excellent.

As the aromatic hydrocarbon ring group or the aromatic heterocyclic group of R ^A , its preferable structure and the substituent which it may have are the structures of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ and the substituent it may have. Same as substituent.

Examples of the substituent for R ^A and the substituent when R ^A is a substituent include the groups described in substituent group W described below.

In formula (113), at least one R ^A is preferably the fluorine-substituted alkyl group, and is preferably a perfluoroalkyl group, since the stability of the anion is further increased and the effect of stabilizing the cation is further improved. A trifluoromethyl group is preferable, and a trifluoromethyl group is more preferable.

The crosslinking group of R ^A and the crosslinking group when R ^A is a crosslinking group are as described above.

In formula (113), it is preferable that at least one R ^A contains the crosslinking group from the viewpoint of achieving both crosslinkability and electron accepting property. At this time, R ^A is preferably the aforementioned crosslinking group, or a structure in which one or more of the aforementioned crosslinking groups are bonded to an aromatic hydrocarbon group.

Furthermore, it is also preferable that R ^A is a group represented by the following formula (114) or a group containing a group represented by the following formula (115).

The group represented by formula (114) and the group represented by formula (115) may have a substituent, and examples of the substituent include the substituent that R ^A may have. is the same as

R ^A is a group represented by formula (114) or a group represented by formula (115), or a group represented by formula (114) or a group represented by formula (115) is A structure in which one or more of these groups is bonded to an aromatic hydrocarbon group is preferred.

When R ^A has a structure in which one or more of the bridging groups are bonded to an aromatic hydrocarbon group, the aromatic hydrocarbon group is selected from a benzene ring, a naphthalene ring, or a benzene ring and a naphthalene ring. It is preferable to have a structure in which two or more molecules are connected, and the number of connections is preferably four or less. In this case, R ^A is more preferably a structure in which the bridging group is bonded to a monocyclic benzene ring or a monocyclic naphthalene ring, and more preferably a structure in which the bridging group is bonded to a benzene ring. A structure in which one or two crosslinking groups are bonded is particularly preferred.

When R ^A is a group represented by the formula (114) or a group represented by the following formula (115), more preferable R ^A is a group represented by the formula (114) on a monocyclic benzene ring or a monocyclic naphthalene ring. ) is a structure in which a group represented by formula (115) is bonded, and a group represented by formula (114) or a group represented by formula (115) is bonded to a benzene ring. A structure in which one or two groups represented by formula (114) or formula (115) are bonded is particularly preferred.

The group represented by formula (114) and the group represented by formula (115) are preferable because they have crosslinking properties and are thought to prevent the tetraarylborate ion and counter cation from diffusing into other layers.

(Substituent group W)
Substituent group W includes a hydrogen atom, a halogen atom, a cyano group, an aromatic hydrocarbon ring group consisting of 1 to 5 aromatic hydrocarbon rings, an aliphatic hydrocarbon ring group, an alkyl group, an alkenyl group, an alkynyl group, and an aralkyl group. group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkylketone group or arylketone group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like, with a fluorine atom being preferred from the viewpoint of stability of the compound.

Examples of the aromatic hydrocarbon ring group consisting of 1 to 5 aromatic hydrocarbon rings include phenyl group, biphenyl group, terphenyl group, quaterphenyl group, naphthyl group, phenanthrenyl group, triphenylene group, naphthylphenyl group, etc. A phenyl group, a naphthyl group, a biphenyl group, a terphenyl group or a quaterphenyl group is preferable from the viewpoint of stability of the compound.

Examples of the aliphatic hydrocarbon ring group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like.

The alkyl group usually has 1 or more carbon atoms, preferably 4 or more, usually 24 or less, preferably 12 or less, more preferably 8 or less, and even more preferably 6 or less. Specifically, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, octyl group. group, 2-ethylhexyl group, dodecyl group, etc.

The alkenyl group usually has 2 or more carbon atoms, usually 24 or less, and preferably 12 or less carbon atoms. Specific examples include vinyl group, propenyl group, butenyl group, and the like.

The alkynyl group usually has 2 or more carbon atoms, usually 24 or less, preferably 12 or less, and specifically includes an acetyl group, a propynyl group, a butynyl group, and the like.

Examples of aralkyl groups include benzyl group, phenylethyl group, phenylhexyl group, and the like.

The alkoxy group usually has 1 or more carbon atoms, usually 24 or less carbon atoms, preferably 12 or less carbon atoms, and more preferably 6 carbon atoms or less, and specific examples include methoxy group, ethoxy group, butyloxy group, hexyloxy group, etc. group, octyloxy group, etc.

The aryloxy group usually has 4 or more carbon atoms, preferably 5 or more, more preferably 6 or more, and usually 36 or less, preferably 24 or less, and even more preferably 12 or less. , Specific examples include phenoxy group, naphthyloxy group, and the like.

The alkylthio group usually has 1 or more carbon atoms, usually 24 or less, and preferably 12 or less, and specific examples include methylthio, ethylthio, butylthio, hexylthio, and the like.

The arylthio group usually has 4 or more carbon atoms, preferably 5 or more, and usually 36 or less, preferably 24 or less, and specific examples thereof include phenylthio group, naphthylthio group, etc.

The alkyl ketone group usually has 1 or more carbon atoms, usually 24 or less carbon atoms, preferably 12 or less carbon atoms, and more preferably 6 carbon atoms or less, and specific examples include an acetyl group, an ethyl carbonyl group, and a butyl carbonyl group. , octylcarbonyl group, etc.

The aryl ketone group usually has 5 or more carbon atoms, preferably 7 or more, and usually 25 or less, preferably 13 or less, and specific examples include benzoyl group, naphthylcarbonyl group, etc. .

Further, adjacent substituents may be bonded to each other to form a ring.
Examples of rings formed include a cyclobutene ring and a cyclopentene ring.

Further, these substituents may be further substituted with a substituent, and examples of the substituent include a halogen atom, an alkyl group, an aryl group, or the above-mentioned crosslinking group.

Among these substituents, a halogen atom or an aryl group is preferred in terms of stability of the compound. The most preferred is a halogen atom, and among the halogen atoms, a fluorine atom is preferred.

[Specific example of tetraarylborate ion]
Specific examples of the tetraarylborate ion used in the organic electroluminescent device of the present invention are listed below, but the invention is not limited thereto.

Of the above specific examples, compounds (A-1) and (A-2) are preferred in terms of electron acceptability, heat resistance, and solubility. Furthermore, since it has high stability as a composition for charge transport film, (A-18), (A-19), (A-20), (A-21), (A-25), (A-26) ), (A-28) are more preferred, and (A-19), (A-21), (A-25), (A-26), and (A-28) are particularly preferred from the viewpoint of stability of the organic electroluminescent device. preferable.

In addition, (A-18), (A-19), (A-20), (A-21), (A-25), (A-26), (A-28), (A-29) Since the tetraarylborate ion has a crosslinking group, it can form a "crosslinked electron-accepting compound".

[Electron-accepting ion compound containing tetraarylborate ion]
The tetraarylborate ion is also preferably used as an electron-accepting ion compound containing a tetraarylborate ion. An electron-accepting ionic compound containing a tetraarylborate ion is referred to as a first ionic compound. The first ionic compound consists of the aforementioned tetraarylborate ion, which is an anion, and a counter cation. The first ionic compound is used as an electron-accepting compound.

The counter cation is preferably an iodonium cation, a sulfonium cation, a carbocation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptyltrienyl cation or a ferrocenium cation having a transition metal; Ammonium cations are more preferred, and iodonium cations are particularly preferred.

Preferably, the iodonium cation has a structure represented by the general formula (6) described below, and a more preferable structure is also the same.

Specific examples of the iodonium cation include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, 4-tert-butoxyphenylphenyliodonium cation, 4-methoxyphenylphenyliodonium cation, and 4-isopropylphenyl-4-methyl. Preferred are phenyl iodonium cations and the like.

Specifically, the sulfonium cations include triphenylsulfonium cation, 4-hydroxyphenyldiphenylsulfonium cation, 4-cyclohexylphenyldiphenylsulfonium cation, 4-methanesulfonylphenyldiphenylsulfonium cation, (4-tert-butoxyphenyl)diphenylsulfonium cation, Bis(4-tert-butoxyphenyl)phenylsulfonium cation, 4-cyclohexylsulfonylphenyldiphenylsulfonium cation and the like are preferred.

Specifically, preferred carbocations include trisubstituted carbocations such as triphenylcarbocation, tri(methylphenyl)carbocation, and tri(dimethylphenyl)carbocation.

Specifically, the ammonium cation includes trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tripropylammonium cation, tributylammonium cation, and tri(n-butyl)ammonium cation; N,N-diethylanilinium cation, N , N-2,4,6-pentamethylanilinium cations; and dialkylammonium cations such as di(isopropyl)ammonium cations and dicyclohexylammonium cations.

Specifically, the phosphonium cations include tetraarylphosphonium cations such as tetraphenylphosphonium cation, tetrakis(methylphenyl)phosphonium cation, and tetrakis(dimethylphenyl)phosphonium cation; tetraalkylphosphonium cations such as tetrabutylphosphonium cation and tetrapropylphosphonium cation. etc. are preferred.

Among these, iodonium cations, carbocations, and sulfonium cations are preferred from the viewpoint of film stability of the compound, and iodonium cations are more preferred.

The iodonium cation as the counter cation of the first ionic compound preferably has a structure represented by the following formula (116).

In formula (116), Ar ⁵ and Ar ⁶ each independently represent an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group. The aromatic hydrocarbon ring group or aromatic heterocyclic group as Ar ⁵ and Ar ⁶ can be selected from the same structures as in the case of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ , and preferred structures are also Ar ¹ , The same structures as for Ar ² , Ar ³ and Ar ⁴ can be selected.

Further, the counter cation represented by the above formula (116) is preferably represented by the following formula (117).

In the above formula (117), Ar ⁷ and Ar ⁸ are the same as the substituents that Ar ⁵ and Ar ⁶ in the above formula (116) may have.

The molecular weight of the first ionic compound used in the present invention is usually 900 or more, preferably 1000 or more, more preferably 1200 or more, and usually 10000 or less, preferably 5000 or less, and still more preferably 3000 or less. . If the molecular weight is too small, electron-accepting ability may be reduced due to insufficient delocalization of positive and negative charges, and if the molecular weight is too large, charge transport may be hindered.

[Concrete example]
Specific examples of ionic compounds with iodonium cations are listed below as the first ionic compound in the present invention, but the first ionic compounds are not limited to these.

Among the above specific examples, compounds (B-1) and (B-2) are preferred in terms of electron acceptability, heat resistance, and solubility. Furthermore, since it has high stability as a composition for charge transport film, (B-18), (B-19), (B-20), (B-21), (B-25), (B-26) ), (B-28), and (B-29) are more preferable, and (B-19), (B-21), (B-25), (B-26), ( B-28) and (B-29) are particularly preferred.

[Hole transport material]
The hole injection layer preferably contains a hole transport material, and is preferably formed using a hole transport material. As the hole transport material, a compound having an ionization potential of 4.5 eV to 5.5 eV is preferable from the viewpoint of hole transport ability. Examples include aromatic amine compounds, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, and the like. Among these, aromatic amine compounds are preferred from the viewpoint of amorphousness, solubility in solvents, and visible light transmittance.

Among aromatic amine compounds, aromatic tertiary amine compounds are particularly preferred in the present invention. In addition, the aromatic tertiary amine compound as used in the present invention is a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.

The type of aromatic tertiary amine compound is not particularly limited, but aromatic tertiary amine polymer compounds that are polymeric compounds are preferred. The weight average molecular weight of the polymer compound is preferably 5,000 or more, more preferably 7,000 or more, particularly preferably 10,000 or more, preferably 1,000,000 or less, even more preferably 200,000 or less, and 100,000 or less from the viewpoint of surface smoothing effect. Particularly preferred. Among the aromatic tertiary amine polymer compounds, from the viewpoint of hole transport properties, polymer compounds having a triphenylamine structure in the main chain are more preferred.

[Aromatic tertiary amine polymer compound]
A preferred example of the aromatic tertiary amine polymer compound includes a polymer compound having a repeating unit represented by the following formula (101).

In the above formula (101), j ¹⁰ , k ¹⁰ , l ¹⁰ , m ¹⁰ , n ¹⁰ , and p ¹⁰ each independently represent an integer of 0 or more. However, l ¹⁰ +m ¹⁰ ≧1.

In the above formula (101), Ar ¹¹ , Ar ¹² and Ar ¹⁴ each independently represent a divalent aromatic ring group which may have a substituent. Ar ¹³ represents a divalent aromatic ring group which may have a substituent or a divalent group represented by the following formula (102), and Q ¹¹ and Q ¹² each independently represent an oxygen atom, It represents a hydrocarbon chain having 6 or less carbon atoms which may have a sulfur atom and a substituent, and S ¹ to S ⁴ are each independently represented by a group represented by the following formula (103).

The aromatic ring groups of Ar ¹¹ , Ar ¹² and Ar ¹⁴ are a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or 2, in which a plurality of at least two groups selected from an optionally substituted divalent aromatic hydrocarbon group and an optionally substituted divalent aromatic heterocyclic group are connected. Represents a valence group. The number of carbon atoms in the aromatic ring groups Ar ¹¹ , Ar ¹² and Ar ¹⁴ is preferably 60 or less.

The aromatic hydrocarbon group preferably has 6 or more and 30 or less carbon atoms, and specifically includes a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, and a chrysene ring. , a triphenylene ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring.

The aromatic heterocyclic group preferably has 3 or more and 30 or less carbon atoms, and specifically includes a furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, and oxadiazole ring. , indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, phenanthridine ring, benzimidazole ring, perimidine ring, quinazoline ring, quinazolinone ring, or azulene ring, etc. Examples include valence groups.

Among them, a divalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring or a divalent biphenyl group is preferable because they have excellent charge transport properties, durability, and heat resistance. , a divalent group derived from a fluorene ring or a carbazole ring, or a divalent biphenyl group are more preferred.

Therefore, Ar ¹¹ , Ar ¹² , Ar ¹⁴ is a divalent benzene ring which may have a substituent, a divalent fluorene ring which may have a substituent, or a divalent fluorene ring which may have a substituent. A group selected from a divalent carbazole ring which may be a divalent carbazole ring, or a divalent group in which two or more rings selected from these structures are connected is preferable, and aromatic rings of Ar ¹¹ , Ar ¹² and Ar ¹⁴ The number of carbon atoms in the group is preferably 60 or less.

The substituents that these aromatic ring groups may have can be selected from the substituent group Z2, which is the substituents that the host material may have.

When Ar ¹³ is an aromatic ring group, the same applies to Ar ¹¹ , Ar ¹² , and Ar ¹⁴ .
Ar ¹³ is also preferably a divalent group represented by the following formula (102).

In the above formula (102), R ¹¹ represents an alkyl group, an aromatic ring group, or a trivalent group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group, and these may have a substituent. R ¹² represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group having 40 or less carbon atoms and an aromatic ring group, and these may have a substituent. Ar ³¹ represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have a substituent. The asterisk (*) indicates the bonding position with the nitrogen atom in formula (101).

Specific examples of the aromatic ring group for R ¹¹ include a phenyl ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a trivalent group derived from a connected ring having 30 or less carbon atoms.

Specific examples of the alkyl group for R ¹¹ include trivalent groups derived from methane, ethane, propane, isopropane, butane, isobutane, and pentane.

Specific examples of the aromatic ring group for R ¹² include a phenyl ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a divalent group derived from a connected ring having 30 or less carbon atoms.

Specific examples of the alkyl group for R ¹² include divalent groups derived from methane, ethane, propane, isopropane, butane, isobutane, and pentane.

Specific examples of the aromatic ring group for Ar ³¹ include monovalent groups derived from phenyl rings, naphthalene rings, carbazole rings, dibenzofuran rings, dibenzothiophene rings, and connected rings having 30 or less carbon atoms.

The crosslinking group of Ar ³¹ is not particularly limited, but is similar to the crosslinking group of the electron-accepting compound having the crosslinking group contained in the hole injection layer of the organic electroluminescent device of the present invention, and is ) to (X18) are preferred. Among these, groups derived from a benzocyclobutene ring, a naphthocyclobutene ring, or an oxetane ring, a vinyl group, and an acrylic group are preferred. From the viewpoint of stability of the compound, a group derived from a benzocyclobutene ring or a naphthocyclobutene ring is more preferable.

S ¹ to S ⁴ are each independently a group represented by the following formula (103).

In the above formula (103), q1 and r1 each independently represent an integer from 0 to 6.
q1 and r1 are each independently preferably 0 to 4, more preferably 0 or 1.

Ar ²¹ and Ar ²³ each independently represent a divalent aromatic ring group, and these groups may have a substituent. Ar ²² represents a monovalent aromatic ring group which may have a substituent, and R ¹³ represents an alkyl group, an aromatic ring group, or a divalent group consisting of an alkyl group and an aromatic ring group, which are unsubstituted. It may have a group. Ar ³² represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have a substituent. The asterisk (*) indicates the bonding position with the nitrogen atom in general formula (101).

Examples of the aromatic ring group for Ar ²¹ and Ar ²³ are the same as those for Ar ¹¹ , Ar ¹² and Ar ¹⁴ .

The aromatic ring group of Ar ²² and Ar ³² is an optionally substituted monovalent aromatic hydrocarbon group, an optionally substituted monovalent aromatic heterocyclic group, or a substituent A monovalent group in which a plurality of at least two groups selected from a monovalent aromatic hydrocarbon group which may have a substituent and a monovalent aromatic heterocyclic group which may have a substituent are connected. represents. The number of carbon atoms in the aromatic ring groups Ar ²² and Ar ³² is preferably 60 or less.

Among these, a monovalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring or a biphenyl group are preferred because they have excellent charge transport properties, durability, and heat resistance.

These aromatic ring groups may have a substituent, and the substituent that they may have can be selected from the above-mentioned substituent group Z2.

Examples of the alkyl group or aromatic ring group for R ¹³ are the same as those for R ¹² .

The crosslinking group for Ar ³² is not particularly limited, but is similar to the example of the crosslinking group for Ar ³¹ , and preferred examples are also the same.

Each of the above Ar ¹¹ to Ar ¹⁴ , R ¹¹ , R ¹² , Ar ²¹ to Ar ²³ , Ar ³¹ to Ar ³² , Q ¹¹ , and Q ¹² further has a substituent as long as it does not go against the spirit of the present invention. You can leave it there. The molecular weight of the substituent is usually 400 or less, preferably about 250 or less. The type of substituent is not particularly limited, but examples thereof include one or more types selected from the above-mentioned substituent group Z2.

In particular, among the polymer compounds having a repeating unit represented by the formula (101), a polymer compound having a repeating unit represented by the following formula (104) is preferred because it has extremely high hole injection/transport properties.

In the above formula (104), R ²¹ to R ²⁵ each independently represent an arbitrary substituent. Specific examples of the substituents R ²¹ to R ²⁵ are the same as the substituents described in the substituent group Z2.

Y' represents a divalent aromatic ring group having 30 or less carbon atoms which may have a substituent. Examples of the aromatic ring group for Y' are the same as those for Ar ¹¹ , Ar ¹² and Ar ¹⁴ above, and the substituents that may be included are also the same.

s and t each independently represent an integer of 0 or more and 5 or less.
u, v, and w each independently represent an integer of 0 or more and 4 or less.

Preferred examples of aromatic tertiary amine polymer compounds include polymer compounds containing repeating units represented by the following formula (105) and/or formula (106).

In the above formulas (105) and (106), Ar ⁴⁵ , Ar ⁴⁷ and Ar ⁴⁸ each independently have a monovalent aromatic hydrocarbon group which may have a substituent or a substituent. represents an optional monovalent aromatic heterocyclic group. Ar ⁴⁴ and Ar ⁴⁶ each independently represent a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent. R ⁴¹ to R ⁴³ each independently represent a hydrogen atom or an arbitrary substituent. r is an integer from 0 to 2.

Specific examples, preferred examples, optional substituents, and preferred substituents of Ar ⁴⁵ , Ar ⁴⁷ and Ar ⁴⁸ are the same as those for Ar ²² and Ar ³² , respectively.

Specific examples, preferred examples, optional substituents, and preferred substituents of Ar ⁴⁴ and Ar ⁴⁶ are the same as those for Ar ¹¹ and Ar ¹⁴ , respectively.

R ⁴¹ to R ⁴³ are preferably a hydrogen atom or a substituent listed in the substituent group Z2, and among them are preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, or an aromatic group. is a group heterocyclic group.

r is preferably 0 or 1, more preferably 0.

Preferred specific examples of repeating units represented by formula (105) and formula (106) applicable to the present invention are listed below, but the present invention is not limited thereto.

Other examples of aromatic amine compounds that can be used as hole transport materials include conventionally known compounds that have been used as hole injection/transport layer forming materials in organic electroluminescent devices. For example, aromatic diamine compounds in which tertiary aromatic amine units are connected such as 1,1-bis(4-di-p-tolylaminophenyl)cyclohexane (Japanese Patent Publication No. 194393/1983); 4,4 Aromatic amines containing two or more tertiary amines represented by '-bis[N-(1-naphthyl)-N-phenylamino]biphenyl and having two or more condensed aromatic rings substituted with nitrogen atoms (Japanese) Japanese Patent Application Publication No. 5-234681); Aromatic triamine having a starburst structure which is a derivative of triphenylbenzene (US Pat. No. 4,923,774); N,N'-diphenyl-N,N'- Aromatic diamines such as bis(3-methylphenyl)biphenyl-4,4'-diamine (US Pat. No. 4,764,625); α,α,α',α'-tetramethyl-α,α '-Bis(4-di-p-tolylaminophenyl)-p-xylene (Japanese Unexamined Patent Publication No. 3-269084); Triphenylamine derivative that is sterically asymmetric as a whole molecule (Japanese Unexamined Patent Publication No. 4-129271) (Japanese Unexamined Patent Publication No. 4-175395); Aromatic diamine in which a tertiary aromatic amine unit is linked with an ethylene group (Japanese Unexamined Patent Publication No. 4-175395); -264189); Aromatic diamines having a styryl structure (Japanese Unexamined Patent Publication No. 4-290851); Aromatic tertiary amine units linked with thiophene groups (Japanese Unexamined Patent Publication No. 4-304466); Starburst type aromatic triamine (Japanese Unexamined Patent Publication No. 4-308688); benzylphenyl compound (Japanese Unexamined Patent Publication No. 4-364153); tertiary amine linked with fluorene group (Japanese Unexamined Patent Publication No. 4-364153); 25473); triamine compounds (Japanese Unexamined Patent Publication No. 5-239455); bisdipyridylaminobiphenyl (Japanese Unexamined Patent Publication No. 5-320634); N,N,N-triphenylamine derivatives (Japanese Unexamined Patent Publication No. 5-320634); 6-1972); Aromatic diamines having a phenoxazine structure (Japanese Patent Publication No. 7-138562); Diaminophenylphenanthridine derivatives (Japanese Patent Publication No. 7-252474); Hydrazone compounds (Japanese Patent Publication No. 7-252474); Silazane compounds (U.S. Pat. No. 4,950,950); Silanamine derivatives (Japanese Patent Publication No. 6-49079); Phosphamine derivatives (Japanese Patent Publication No. 6-25659) Publications); quinacridone compounds, etc. These aromatic amine compounds may be used in combination of two or more types, if necessary.

Other specific examples of aromatic amine compounds that can be used as hole transport materials include metal complexes of 8-hydroxyquinoline derivatives having a diarylamino group. The above metal complexes have central metals such as alkali metals, alkaline earth metals, Sc, Y, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Al, Ga, In, Si, Ge, Sn. , Sm, Eu, and Tb, and the 8-hydroxyquinoline ligand has one or more diarylamino groups as a substituent, but may have any substituent other than the diarylamino group. .

Preferred specific examples of phthalocyanine derivatives or porphyrin derivatives that can be used as hole transport materials include porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphyrin, 5,10,15,20-tetra Phenyl-21H,23H-porphyrin cobalt(II), 5,10,15,20-tetraphenyl-21H,23H-porphyrin copper(II), 5,10,15,20-tetraphenyl-21H,23H-porphyrin zinc (II), 5,10,15,20-tetraphenyl-21H,23H-porphyrin vanadium (IV) oxide, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin, 29H,31H - Copper phthalocyanine (II), zinc phthalocyanine (II), titanium phthalocyanine, magnesium phthalocyanine oxide, lead phthalocyanine, copper (II) phthalocyanine, 4,4',4'',4'''-tetraaza-29H,31H-phthalocyanine etc.

Further, preferred specific examples of oligothiophene derivatives that can be used as hole transport materials include α-sexithiophene and the like.

In addition, the molecular weight of these hole transport materials is usually 5000 or less, preferably 3000 or less, more preferably 2000 or less, still more preferably 1700 or less, except in the case of the polymer compound having the above-mentioned specific repeating unit. It is particularly preferably 1,400 or less, usually 200 or more, preferably 400 or more, and more preferably 600 or more. If the molecular weight of the hole transporting material is too large, synthesis and purification will be difficult, which is undesirable, while if the molecular weight is too small, heat resistance may be lowered, which is also undesirable.

The hole injection layer of the organic electroluminescent device of the present invention may contain any one of the above-mentioned hole transport materials alone, or may contain two or more of the above hole transport materials. When the hole injection layer contains two or more hole transport materials, the combination is arbitrary, but one or more aromatic tertiary amine polymer compounds and one or more other hole transport materials may be used. It is preferable to use more than one species in combination. As for the type of hole transport material used in combination with the above-mentioned polymer compound, aromatic amine compounds are preferable.

The content of the hole transporting material in the hole injection layer of the organic electroluminescent device of the present invention is set within a range that satisfies the ratio with the electron-accepting compound described above. When two or more types of charge transport film compositions are used together, the total content thereof should be within the above range.

[Charge transporting ionic compound]
The hole injection layer of the organic electroluminescent device of the present invention preferably contains a charge-transporting ionic compound in which the tetraarylborate ion and the cation radical of the hole-transporting material are ionically bonded.

The hole injection layer of the organic electroluminescent device of the present invention includes a charge transporting ionic compound in which the tetraarylborate ion and the cation radical of the aromatic tertiary amine polymer compound are ionically bonded as a hole transporting material. It is particularly preferred to include.

This charge transporting ionic compound can be obtained by any of the following methods.
i) The first ionic compound and the hole transport material are dissolved or dispersed in an organic solvent and mixed.
ii) The first ionic compound and the hole transport material are dissolved or dispersed in an organic solvent, mixed, and further heated.
iii) The composition obtained in i) or ii) is wet-formed into a film, and the film is heated.

Since the first ionic compound is an electron-accepting compound, the hole transporting material is oxidized by the first ionic compound to become a cation radical in any of the above methods. As a result, a charge-transporting ionic compound is generated, which is an ionic compound having the tetraarylborate ion as a counter-anion and the cation radical of the hole-transporting material as a counter-cation.

The hole injection layer of the organic electroluminescent device of the present invention preferably contains a first ionic compound containing the tetraarylborate ion as a counter anion and a hole transport material, From the viewpoint of charge transportability, it is more preferable that the material contains a charge transporting ionic compound having a cation radical of the hole transporting material as a counter cation.

[Composition for forming hole injection layer]
The hole injection layer of the organic electroluminescent device of the present invention is preferably obtained by wet film formation of a composition for forming a hole injection layer.

The composition for forming a hole injection layer may be a composition obtained through a step of dissolving or dispersing the first ionic compound having the tetraarylborate ion structure and the hole transport material in an organic solvent. preferable.

From the viewpoint of obtaining a uniform hole injection layer film, the hole injection layer forming composition is preferably a solution in which the first ionic compound and the hole transport material are dissolved in an organic solvent.

Even if the composition for forming a hole injection layer obtained by the method i) does not contain the charge transporting ion compound, the charge transporting ion can be added by the method ii) or iii). Even if the charge transporting ionic compound is not contained in the hole injection layer forming composition obtained by the method ii), the charge transporting ionic compound can be obtained by the method iii). It is sufficient if an ionic compound can be obtained.

The blending ratio of the first ionic compound and the hole transport material to obtain the composition for forming a hole injection layer is such that the amount of the first ionic compound is based on 100 parts by mass of the hole transport material. The amount is usually 0.1 parts by mass or more, preferably 1 part by mass or more, and usually 100 parts by mass or less, preferably 40 parts by mass or less. If the content of the first ionic compound is at least the above-mentioned lower limit, free carriers (cation radicals of the hole-transporting material) can be sufficiently generated and hole-transporting properties are improved, which is preferable. , is preferable because sufficient charge transport ability can be ensured. When two or more of the first ionic compounds are used in combination, the total content thereof should be within the above range. The same applies to the hole transport material.

(Organic solvent)
The concentration of the organic solvent in the composition for forming a hole injection layer is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and usually 99% by mass or more. The range is .999% by mass or less, preferably 99.99% by mass or less, and more preferably 99.9% by mass or less. In addition, when using a mixture of two or more types of organic solvents, the total of these organic solvents should satisfy this range.

Preferred organic solvents include, for example, ether solvents and ester solvents. Specifically, examples of ether solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3 Examples include aromatic ethers such as -dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole. Examples of ester solvents include aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and benzoic acid. Examples include aromatic esters such as n-butyl. Any one of these may be used alone, or two or more may be used in any combination and ratio.

Examples of solvents that can be used in addition to the above-mentioned ether solvents and ester solvents include aromatic hydrocarbon solvents such as benzene, toluene, and xylene, and amides such as N,N-dimethylformamide and N,N-dimethylacetamide. Examples include solvents, dimethyl sulfoxide, and the like. Any one of these may be used alone, or two or more may be used in any combination and ratio. Furthermore, one or more of these solvents may be used in combination with one or more of the above-mentioned ether solvents and ester solvents. In particular, aromatic hydrocarbon solvents such as benzene, toluene, and xylene have a low ability to dissolve electron-accepting compounds and free carriers (cation radicals), so they cannot be used in combination with ether solvents and ester solvents. preferable.

Among these organic solvents, solvents having an aromatic hydrocarbon structure are more preferred.

(Film forming method)
The hole injection layer can be formed by wet film formation using a composition for forming a hole injection layer. The wet film-forming method is similar to the method of forming a light-emitting layer forming composition by wet film-forming, but it is preferable to heat the composition after coating and drying. The heating temperature is preferably 120°C or higher, more preferably 150°C or higher, more preferably 180°C or higher, preferably 300°C or lower, and even more preferably 260°C or lower.

The hole injection layer can be crosslinked by heating the film after coating and drying. At this time, a crosslinking reaction may occur in the following combinations.

- Crosslinking groups of hole transporting materials - Crosslinking groups of hole transporting materials and crosslinking groups of electron-accepting compounds - Crosslinking groups of electron-accepting compounds - Crosslinking groups of hole transporting materials and tetraarylboric acid in the present invention Crosslinking groups of ions, crosslinking groups of tetraarylborate ions in the present invention, crosslinking groups of electron-accepting compounds and crosslinking groups of tetraarylborate ions in the present invention. Through this step, the hole injection layer has the electron-accepting properties. A crosslinked product of the compound is formed.

In addition, heating promotes the formation of a charge-transporting ionic compound, which is an ionic compound of a tetraarylborate ion, which is a counteranion of the first ionic compound, and a cation radical of the hole-transporting material, and is therefore preferable.

<Structure of organic electroluminescent device>
As an example of the structure of the organic electroluminescent device of the present invention, FIG. 1 shows a schematic diagram (cross section) of a structural example of an organic electroluminescent device 8. As shown in FIG. In FIG. 1, 1 represents a substrate, 2 an anode, 3 a hole injection layer, 4 a hole transport layer, 5 a light emitting layer, 6 an electron transport layer, and 7 a cathode.

[substrate]
The substrate 1 serves as a support for the organic electroluminescent element, and typically includes a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like. Among these, glass plates and plates made of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. The substrate is preferably made of a material with high gas barrier properties, since deterioration of the organic electroluminescent element by outside air is unlikely to occur. For this reason, especially when using a material with low gas barrier properties such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one side of the substrate to improve the gas barrier properties.

[anode]
The anode 2 has a function of injecting holes into the layer on the light emitting layer 5 side.

The anode 2 is usually made of metals such as aluminum, gold, silver, nickel, palladium, and platinum; metal oxides such as indium and/or tin oxides; metal halides such as copper iodide; carbon black and poly(3 -Methylthiophene), polypyrrole, polyaniline, and other conductive polymers.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum evaporation method. In addition, when forming an anode using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., it is necessary to add a suitable binder resin solution to the anode. It can also be formed by dispersing it and coating it on the substrate. In the case of conductive polymers, it is also possible to form a thin film directly on the substrate by electrolytic polymerization, or to form an anode by coating the conductive polymer on the substrate (Appl. Phys. Lett., 60 Vol. 2711, 1992).

The anode 2 usually has a single layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first layer of the anode.

The thickness of the anode 2 may be determined depending on the required transparency, material, etc. When particularly high transparency is required, the thickness is preferably such that the visible light transmittance is 60% or more, and the thickness is more preferably such that the visible light transmittance is 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. On the other hand, if transparency is not required, the thickness of the anode 2 may be set arbitrarily depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate.

When forming another layer on the surface of the anode 2, impurities on the anode 2 are removed and its ionization potential is It is preferable to adjust the hole injection property to improve the hole injection property.

[Hole injection layer]
The hole injection layer in the organic electroluminescent device of the present invention is as described above. Regarding the method for forming the hole injection layer, although the wet film forming method was described above, a vacuum evaporation method may also be used.

[Formation of hole injection layer by vacuum evaporation method]
When the hole injection layer of the organic electroluminescent device of the present invention is formed by vacuum evaporation, the first ionic compound is used as the material containing tetraarylborate ions, and the hole transport material is a vapor-depositable Molecular hole transport materials can be used. As the low molecular weight hole transport material that can be vapor deposited, a hole transport material with a molecular weight of 1500 or less is preferable, a hole transport material with a molecular weight of 1000 or less is more preferable, a hole transport material with a molecular weight of 400 or more is preferable, and a hole transport material with a molecular weight of 600 or less is preferable. The above hole transport materials are more preferred. As the low molecular hole transport material, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are more preferred.

When forming the hole injection layer 3 by vacuum evaporation, one or more of the constituent materials of the hole injection layer 3 are usually placed in a crucible placed in a vacuum container (two or more materials (When using crucibles, each crucible is usually placed in a separate crucible), and the inside of the vacuum container is evacuated to about 10 ^-4 Pa with a vacuum pump. After that, the crucible is heated (when using two or more types of materials, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the amount of evaporation (when using two or more types of materials). are usually evaporated while controlling the amount of evaporation independently) to form a hole injection layer on the anode on the substrate placed facing the crucible. Note that when two or more types of materials are used, a mixture thereof can be placed in a crucible, heated, and evaporated to form a hole injection layer.

The degree of vacuum during vapor deposition is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1×10 ⁻⁶ Torr (0.13×10 ⁻⁴ Pa) or more, 9.0×10 ⁻⁶ Torr ( 12.0×10 ⁻⁴ Pa) or less. The deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å/sec or more and 5.0 Å/sec or less. The film forming temperature during vapor deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or higher and 50°C or lower.

[Hole transport layer]
The hole transport layer 4 is a layer that has the function of transporting holes from the anode 2 side to the light emitting layer 5 side. Although the hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, it is preferable to form this layer in terms of strengthening the function of transporting holes from the anode 2 to the light emitting layer 5. . When forming the hole transport layer 4, the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. Further, if the hole injection layer 3 described above is present, it is formed between the hole injection layer 3 and the light emitting layer 5.

The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and on the other hand, usually 300 nm or less, preferably 100 nm or less.

The method for forming the hole transport layer 4 may be a vacuum evaporation method or a wet film formation method. In terms of excellent film-forming properties, it is preferable to form the film by a wet film-forming method.

The hole transport layer 4 usually contains a hole transport compound.

Hole transporting compounds include two or more fused aromatic compounds containing two or more tertiary amines, typified by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl. Aromatics with a starburst structure such as aromatic diamines in which the ring is substituted with a nitrogen atom (Japanese Unexamined Patent Publication No. 5-234681), 4,4',4''-tris(1-naphthylphenylamino)triphenylamine, etc. Aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., 2175 pages, 1996), 2,2 Spiro compounds such as ',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, vol. 91, p. 209, 1997), 4,4'-N,N' Preferred examples include carbazole derivatives such as dicarbazole biphenyl. Also, for example, polyvinylcarbazole, polyvinyltriphenylamine (Japanese Unexamined Patent Publication No. 7-53953), polyarylene ether sulfone containing tetraphenylbenzidine (Polym.Adv.Tech., vol. 7, p. 33, 1996) etc. may also be included.

[Formation of hole transport layer by wet film formation method]
When forming a hole transport layer by a wet film formation method, the hole injection layer is usually formed in the same way as in the case of forming a hole injection layer by a wet film formation method, in place of the hole injection layer forming composition. It is formed using a composition for forming a transport layer.

When forming a hole transport layer by a wet film forming method, the composition for forming a hole transport layer usually further contains an organic solvent. As the organic solvent used in the composition for forming a hole transport layer, the same organic solvent as the organic solvent used in the composition for forming a hole injection layer described above can be used.

The concentration of the hole transporting compound in the composition for forming a hole transporting layer can be in the same range as the concentration of the hole transporting compound in the composition for forming a hole injection layer.

[Formation of hole transport layer by vacuum evaporation method]
When forming a hole transport layer using a vacuum evaporation method, normally, in the same manner as when forming a hole injection layer using a vacuum evaporation method, a hole transport layer is used instead of the hole injection layer forming composition. It can be formed using a layer-forming composition. The film forming conditions such as the degree of vacuum, the vapor deposition rate, and the temperature during vapor deposition can be the same as those for the vacuum vapor deposition of the hole injection layer.

[Light-emitting layer]
The light-emitting layer 5 is a layer that is excited by recombining holes injected from the anode 2 and electrons injected from the cathode 7 when an electric field is applied between a pair of electrodes, and has the function of emitting light. . The light emitting layer 5 is a layer formed between the anode 2 and the cathode 7, and if there is a hole injection layer on the anode, the light emitting layer is formed between the hole injection layer and the cathode, and the light emitting layer is a layer formed between the anode 2 and the cathode. If there is a hole transport layer on top of the hole transport layer, it is formed between the hole transport layer and the cathode.

As described above, the light-emitting layer of the organic electroluminescent device in the present invention contains the polycyclic heterocyclic compound represented by formula (1) and the organometallic compound represented by formula (201), and further contains the host material. is even more preferable.

The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention, but a thicker layer is preferable because defects are less likely to occur in the layer, and a thinner layer is preferable because it is easier to lower the driving voltage. . For this reason, it is preferably 3 nm or more, more preferably 5 nm or more, and on the other hand, it is usually preferably 200 nm or less, and even more preferably 100 nm or less.

The light-emitting layer 5 contains at least a material having light-emitting properties (light-emitting material), and preferably contains one or more host materials.

[Hole blocking layer]
A hole blocking layer may be provided between the light emitting layer 5 and the electron injection layer described below. The hole blocking layer is a layer stacked on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 7 side.

This hole blocking layer has the role of blocking holes moving from the anode 2 from reaching the cathode 7 and the role of efficiently transporting electrons injected from the cathode 7 toward the light emitting layer 5. have The physical properties required of the material constituting the hole blocking layer include high electron mobility and low hole mobility, large energy gap (difference between HOMO and LUMO), and excited triplet level (T ₁ ). One example is the high level of

Examples of materials for the hole blocking layer that satisfy these conditions include bis(2-methyl-8-quinolinolato)(phenolato)aluminum, bis(2-methyl-8-quinolinolato)(triphenylsilanolate)aluminum, etc. mixed ligand complexes, metal complexes such as bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolilato)aluminum dinuclear metal complexes, distyrylbiphenyl derivatives, etc. Styryl compounds (Japanese Unexamined Patent Publication No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole ( Japanese Patent Application Publication No. 7-41759), phenanthroline derivatives such as bathocuproine (Japanese Patent Application Publication No. 10-79297), and the like. Furthermore, a compound having at least one pyridine ring substituted at the 2, 4, and 6 positions described in International Publication No. 2005/022962 is also preferable as a material for the hole blocking layer.

There are no restrictions on the method of forming the hole blocking layer. Therefore, it can be formed by a wet film formation method, a vapor deposition method, or other methods.

The thickness of the hole blocking layer is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less. .

[Electron transport layer]
The electron transport layer 6 is provided between the light emitting layer 5 and the cathode 7 for the purpose of further improving the current efficiency (cd/A) of the device.

The electron transport layer 6 is formed of a compound that can efficiently transport electrons injected from the cathode 7 toward the light emitting layer 5 between the electrodes to which an electric field is applied. The electron-transporting compound used in the electron-transporting layer 6 must be a compound that has high electron injection efficiency from the cathode 7, has high electron mobility, and can efficiently transport the injected electrons. is necessary.

Specifically, examples of the electron transporting compound used in the electron transporting layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Unexamined Patent Publication No. 59-194393), 10-hydroxybenzo[h] Quinoline metal complexes, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Unexamined Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Unexamined Patent Publication No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyano Examples include anthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

The film thickness of the electron transport layer 6 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The electron transport layer 6 is formed by laminating it on the hole blocking layer using a wet film formation method or a vacuum evaporation method in the same manner as described above. Usually, a vacuum evaporation method is used.

[Electron injection layer]
The electron injection layer may be provided to efficiently inject electrons injected from the cathode 7 into the electron transport layer 6 or the light emitting layer 5.

In order to efficiently inject electrons, the material forming the electron injection layer is preferably a metal with a low work function. Examples include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the like. The film thickness is usually preferably 0.1 nm or more and 5 nm or less.

Furthermore, organic electron transport materials such as nitrogen-containing heterocyclic compounds such as bathophenanthroline and metal complexes such as aluminum complexes of 8-hydroxyquinoline are doped with alkali metals such as sodium, potassium, cesium, lithium, and rubidium ( (described in Japanese Unexamined Patent Publication No. 10-270171, Japanese Unexamined Patent Publication No. 2002-100478, Japanese Unexamined Patent Application No. 2002-100482, etc.) also improves electron injection and transport properties and achieves excellent film quality. This is preferable because it makes it possible to

The thickness of the electron injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer is formed by laminating it on the light emitting layer 5 or the hole blocking layer or electron transport layer 6 thereon by a wet film formation method or a vacuum evaporation method.
The details in the case of the wet film forming method are the same as in the case of the above-mentioned light emitting layer.

In some cases, the hole-blocking layer, electron-transporting layer, and electron-injecting layer are made into a single layer by co-doping an electron-transporting material and a lithium complex.

[cathode]
The cathode 7 plays a role of injecting electrons into a layer (such as an electron injection layer or a light emitting layer) on the side of the light emitting layer 5 .

As the material for the cathode 7, it is possible to use the material used for the anode 2, but in order to efficiently inject electrons, it is preferable to use a metal with a low work function, such as tin, magnesium, etc. , indium, calcium, aluminum, silver, or alloys thereof. Specific examples include low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy, and the like.

In terms of the stability of the organic electroluminescent device, it is preferable to protect the cathode made of a metal with a low work function by laminating a metal layer with a high work function and stable against the atmosphere on the cathode. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.

The film thickness of the cathode is usually the same as that of the anode.

[Other layers]
The organic electroluminescent device of the present invention may further have other layers as long as the effects of the present invention are not significantly impaired. That is, any other layer mentioned above may be provided between the anode and the cathode.

[Other element configurations]
The organic electroluminescent device of the present invention has a structure opposite to that described above, that is, for example, on a substrate, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, a hole It is also possible to stack the injection layer and the anode in this order.

When applying the organic electroluminescent device of the present invention to an organic electroluminescent device, it may be used as a single organic electroluminescent device or in a configuration in which a plurality of organic electroluminescent devices are arranged in an array. A structure in which anodes and cathodes are arranged in an XY matrix may also be used.

<Method for manufacturing organic electroluminescent device>
There are no particular limitations on the method for manufacturing the organic electroluminescent device of the present invention. Preferably, as described above, an organic electroluminescent element having an anode, a light emitting layer, and a cathode in this order on a substrate is prepared by including a step of forming a light emitting layer by a wet film forming method using the composition of the present invention. can be manufactured.

<Organic EL display device>
The organic EL display device (organic electroluminescent device display device) of the present invention includes the organic electroluminescent device of the present invention. There are no particular restrictions on the type or structure of the organic EL display device of the present invention, and it can be assembled using the organic electroluminescent device of the present invention according to a conventional method.

For example, the organic EL display device of the present invention can be manufactured by the method described in "Organic EL Display" (Ohmsha, published August 20, 2004, written by Shizushi Tokito, Chihaya Adachi, and Hideyuki Murata). can be formed.

<Organic EL lighting>
The organic EL lighting (organic electroluminescent device lighting) of the present invention includes the organic electroluminescent device of the present invention. There are no particular restrictions on the type or structure of the organic EL lighting of the present invention, and it can be assembled using the organic electroluminescent device of the present invention according to conventional methods.

<Example of embodiment>
[Example of creating an organic electroluminescent device]
The organic electroluminescent device can be produced by the following method.
The glass substrate patterned with ITO is cleaned.
A hole injection layer forming composition is wet-formed on a substrate and dried by heating to form a hole injection layer.
A hole transport layer forming composition is wet-formed on the hole injection layer, and dried by heating to form a hole transport layer.
A composition for forming a light emitting layer is wet-formed on the hole transport layer and dried by heating to form a light emitting layer.

[Example 1 of embodiment]
Although there is no particular limitation, the organic electroluminescent device can be produced, for example, by the following method.
An indium tin oxide (ITO) transparent conductive film deposited to a thickness of 50 nm on a glass substrate (manufactured by Geomatec, sputter film deposited) was formed into 2 mm wide stripes using normal photolithography technology and hydrochloric acid etching. pattern to form an anode. The substrate on which ITO was patterned was washed in the following order: ultrasonic cleaning with an aqueous surfactant solution, ultrapure water, ultrasonic cleaning with ultrapure water, and ultrapure water, and then dried with compressed air. , Finally, perform ultraviolet ozone cleaning.
As a composition for forming a hole injection layer, 3.0% by weight of a hole transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by weight of an electron accepting compound (HI-1). A composition is prepared by dissolving these in ethyl benzoate.

This solution is spin-coated on the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of, for example, 40 nm, which is used as a hole injection layer.

Next, a charge transporting polymer compound having the following structural formula (HT-1) is dissolved in 1,3,5-trimethylbenzene to prepare a 2.0% by weight solution.
This solution is spin-coated on the substrate on which the hole injection layer has been coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of, for example, 40 nm. to form a hole transport layer.

Subsequently, as materials for the light emitting layer, 2.6% by weight of a host material (H-1) having the following structure, 2.6% by weight of a host material (H-2), and an organometallic compound (A-a1) ( Cyclohexyl (molecular weight 1592.16) at a concentration of 1.56% by weight and polycyclic heterocyclic compound (D-1), (D-2), or (D-3) as a luminescent compound at a concentration of 0.26% by weight. A composition for forming a light-emitting layer is prepared by dissolving it in benzene.

This solution is spin-coated on the substrate on which the hole transport layer has been coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of, for example, 70 nm. to form a light-emitting layer. The organometallic compound represented by formula (A-a1) has a molecular weight of 1592.16 and a maximum emission wavelength of 555 nm, and has a molecular weight of 1592.16 and a maximum emission wavelength of 555 nm. The maximum emission wavelengths of the luminescent compounds are 613 nm, 628 nm, and 619 nm, respectively, and satisfy formula (E-3).
The substrate on which the film up to the light-emitting layer has been formed is placed in a vacuum evaporation device, and the inside of the device is evacuated to a pressure of 2×10 ⁻⁴ Pa or less.

Next, the following structural formula (ET-1) and 8-hydroxyquinolinolatrithium are co-deposited on the light emitting layer at a film thickness ratio of 2:3 using a vacuum evaporation method, for example, an electron transporting layer with a film thickness of 30 nm. form a layer.

Next, a striped shadow mask with a width of 2 mm is brought into close contact with the substrate as a mask for cathode evaporation so as to be perpendicular to the ITO stripes of the anode, and the aluminum is heated with a molybdenum boat to form an aluminum layer with a thickness of, for example, 80 nm. to form a cathode. In the manner described above, an organic electroluminescent device having a light emitting area of 2 mm x 2 mm can be obtained.

[Example 2 of embodiment]

As the charge-transporting polymer compound for the hole-transporting layer, a polymer compound represented by the following structural formula (HT-a1) can also be used.

[Example 3 of embodiment]
As materials for the light emitting layer, 1.17% by weight of the following host material (H-a1), 1.17% by weight of the following host material (H-a2), 0.78% by weight of the compound (H-2), The organometallic compound (A-a1) is dissolved in cyclohexylbenzene at a concentration of 0.93% by weight and the polycyclic heterocyclic compound (D-1) at a concentration of 0.16% by weight to prepare a composition for forming a light emitting layer. However, it can be used as a composition for forming a light emitting layer.

Incidentally, when T1A, T1B, and S1B are determined by the method described in the main text for Embodiment Example 1 and Embodiment Example 3, they all satisfy the relationships of formula (E-1) and formula (E-2).

[Example 1]
An organic electroluminescent device was produced by the following method.
An indium tin oxide (ITO) transparent conductive film deposited to a thickness of 50 nm on a glass substrate (manufactured by Geomatec, sputtering film) was formed into 2 mm wide stripes using normal photolithography technology and hydrochloric acid etching. The anode was formed by patterning. The substrate on which ITO was patterned was washed in the following order: ultrasonic cleaning with an aqueous surfactant solution, washing with ultrapure water, ultrasonic washing with ultrapure water, and washing with ultrapure water, and then dried with compressed air. Finally, ultraviolet ozone cleaning was performed.
As a composition for forming a hole injection layer, 3.0% by weight of a hole transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by weight of an electron accepting compound (HI-1). A composition was prepared by dissolving these in ethyl benzoate.

This solution was spin-coated on the substrate in the air and dried on a hot plate in the air at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.

Next, a charge transporting polymer compound having the following structural formula (HT-1) was dissolved in 1,3,5-trimethylbenzene to prepare a 2.0% by weight solution.
This solution was spin-coated on the substrate on which the hole injection layer was coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of 40 nm. and formed a hole transport layer.

Subsequently, as materials for the light emitting layer, 2.4% by weight of a host material (H-1) having the following structure, 0.8% by weight of a host material (H-2), and an organometallic compound (A-1) ( A composition for forming a light-emitting layer was prepared by dissolving 0.96% by weight of the compound (with a molecular weight of 2168.94) and 0.064% by weight of the light-emitting compound (D-1) in cyclohexylbenzene.

This solution was spin-coated on the substrate on which the hole transport layer was coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of 40 nm. A light-emitting layer was formed.
The substrate on which the film up to the light-emitting layer was formed was placed in a vacuum evaporation apparatus, and the inside of the apparatus was evacuated to a pressure of 2×10 ⁻⁴ Pa or less.

Next, a compound (ET-1) represented by the following structural formula and 8-hydroxyquinolinolatrithium were co-deposited on the light-emitting layer by vacuum evaporation at a film thickness ratio of 2:3. A 30 nm electron transport layer was formed.

Next, a striped shadow mask with a width of 2 mm was brought into close contact with the substrate as a mask for cathode evaporation, perpendicular to the ITO stripes of the anode, and the aluminum was heated with a molybdenum boat to form an aluminum layer with a thickness of 80 nm. was formed to form a cathode. In the manner described above, an organic electroluminescent device having a light emitting area of 2 mm x 2 mm in size was obtained.

[Example 2]
Same as Example 1 except that the organometallic compound (A-2) represented by the following structural formula (molecular weight 1922.51) was used instead of the organometallic compound (A-1) as the material of the light emitting layer. An organic electroluminescent device was prepared using the following steps.

[Example 3]
Same as Example 1 except that the organometallic compound (A-3) represented by the following structural formula (molecular weight 1694.21) was used instead of the organometallic compound (A-1) as the material of the light emitting layer. An organic electroluminescent device was prepared using the following steps.

[Example 4]
Same as Example 1 except that the organometallic compound (A-4) represented by the following structural formula (molecular weight 1347.74) was used instead of the organometallic compound (A-1) as the material for the light emitting layer. An organic electroluminescent device was prepared using the following steps.

[Comparative example 1]
Same as Example 1 except that the organometallic compound (CA-1) represented by the following structural formula (molecular weight 1177.65) was used instead of the organometallic compound (A-1) as the material of the light emitting layer. An organic electroluminescent device was prepared using the following steps.

[Comparative example 2]
Same as Example 1 except that an organometallic compound (CA-2) represented by the following structural formula (molecular weight 823.11) was used instead of the organometallic compound (A-1) as the material of the light emitting layer. An organic electroluminescent device was prepared using the following steps.

[Example 5]
An organic electroluminescent device was prepared in the same manner as in Example 1, except that 0.96% by weight of an organometallic compound (A-11) (molecular weight 1592.16) having the following structure was used as the organometallic compound of the light emitting layer. Created.

[Example 6]
As the material for the light emitting layer, instead of using the host material (H-1) and the host material (H-2), 3.2% by weight of the host material (CH-1) represented by the following structural formula was used. An organic electroluminescent device was produced in the same manner as in Example 5.

[Triplet energy levels of organometallic compounds and luminescent compounds]
The triplet energy levels of the organometallic compounds and luminescent compounds in Examples 1 to 4, Comparative Examples 1 and 2, and Examples 5 and 6 satisfy formula (E-1).

The triplet energy levels of the organometallic compounds in Examples 1 to 4, Comparative Examples 1 and 2, and Examples 5 and 6 were calculated from the peak wavelength of the phosphorescence spectrum of the solutions at room temperature. Similarly, the singlet energy level of the luminescent compound was calculated from the peak wavelength of the fluorescence spectrum at room temperature. The energy difference (ΔEST) between the singlet energy level and triplet energy of the luminescent compound was calculated from the peak wavelength of the fluorescence spectrum and phosphorescence spectrum at 77K. Using these, the triplet energy level of the luminescent compound at room temperature was calculated. These results are summarized in Table 1. It can be seen that the triplet energy levels of the organometallic compounds and luminescent compounds in Examples 1 to 4, Comparative Examples 1 and 2, and Examples 5 and 6 satisfy formula (E-1).

[Evaluation of element]
When the organic electroluminescent devices obtained in Examples 1 to 4, Comparative Examples 1 and 2, and Examples 5 and 6 were continuously energized at a current density of 60 mA/cm ² , the brightness was 90% of the initial brightness. The time required for the temperature to decrease to LT90 (LT90) was measured. The measurement results are shown in Table 2. The numerical values of Examples 1 to 6 and Comparative Examples 1 and 2 indicate the relative life of each Example and Comparative Example when LT90 of Comparative Example 2 is set to 1.00.
From the results in Table 2, it was found that the organic electroluminescent device of the present invention has a long life.

[Example 7]
An organic electroluminescent device was produced by the following method.
An indium tin oxide (ITO) transparent conductive film deposited to a thickness of 50 nm on a glass substrate (manufactured by Geomatec, sputter film deposited) was formed into 2 mm wide stripes using normal photolithography technology and hydrochloric acid etching. The anode was formed by patterning. The substrate on which ITO was patterned was washed in the following order: ultrasonic cleaning with an aqueous surfactant solution, ultrapure water, ultrasonic cleaning with ultrapure water, and ultrapure water, and then dried with compressed air. Finally, ultraviolet ozone cleaning was performed.
As a composition for forming a hole injection layer, 3.0% by weight of a hole transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by weight of an electron accepting compound (HI-1). A composition was prepared by dissolving these in ethyl benzoate.

This solution was spin-coated on the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.
Next, a charge transporting polymer compound having the following structural formula (HT-2) was dissolved in 1,3,5-trimethylbenzene to prepare a 2.0% by weight solution.
This solution was spin-coated on the substrate on which the hole injection layer was coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 230°C for 30 minutes to form a uniform thin film with a thickness of 40 nm. and formed a hole transport layer.

Subsequently, as materials for the light emitting layer, 2.4% by weight of a host material (H-1) having the following structure, 0.8% by weight of a host material (H-2), and an organometallic compound (A-12) ( A composition for forming a light-emitting layer was prepared by dissolving 0.96% by weight of the compound (with a molecular weight of 1271.64) and 0.064% by weight of the light-emitting compound (D-1) in cyclohexylbenzene.

This solution was spin-coated on the substrate on which the hole transport layer was coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a thickness of 40 nm. A light-emitting layer was formed.
The substrate on which the film up to the light-emitting layer was formed was placed in a vacuum evaporation apparatus, and the inside of the apparatus was evacuated to a pressure of 2×10 ⁻⁴ Pa or less.
Next, a compound (ET-1) represented by the following structural formula and 8-hydroxyquinolinolatrithium were co-deposited on the light-emitting layer by vacuum evaporation at a film thickness ratio of 2:3. A 30 nm electron transport layer was formed.

[Example 8]
As the host material of the light emitting layer, instead of using host material (H-1) and host material (H-2), only host material (H-1) was used, and host material (H-1) was 2.8% by weight. , except that a composition for forming a luminescent layer was prepared by dissolving the organometallic compound (A-12) in a concentration of 0.84% by weight and the luminescent compound (D-1) in a concentration of 0.056% by weight in cyclohexylbenzene. An organic electroluminescent device was produced in the same manner as in Example 7.

[Example 9]
As the host material of the light emitting layer, instead of using host material (H-1) and host material (H-2), only host material (H-3) having the following structure is used, and host material (H-3) is A composition for forming a luminescent layer was prepared by dissolving in cyclohexylbenzene at a concentration of 3.2% by weight, 0.96% by weight of the organometallic compound (A-12), and 0.064% by weight of the luminescent compound (D-1). An organic electroluminescent device was produced in the same manner as in Example 7 except for the preparation.

[Example 10]
Instead of using host material (H-1) and host material (H-2) as the host material of the light emitting layer, only host material (H-4) having the following structure is used, and host material (H-4) is dissolved in cyclohexylbenzene at a concentration of 3.2% by weight, 0.96% by weight of the organometallic compound (A-12), and 0.064% by weight of the luminescent compound (D-1) to form a composition for forming a luminescent layer. An organic electroluminescent device was produced in the same manner as in Example 7, except that .

[Triplet energy levels of organometallic compounds and luminescent compounds]
The triplet energy level of the organometallic compound (A-12) used in Examples 7 to 10 was calculated using the method described above and was found to be 2.5 eV. Further, as shown in Table 1, the triplet energy level of the light-emitting compound (D-1) was 1.84 eV.
Therefore, the triplet energy levels of the organometallic compound and the light-emitting compound in Examples 7 to 10 satisfy formula (E-1).

[Evaluation of element]
When the organic electroluminescent devices obtained in Examples 7 to 10 were continuously energized at a current density of 60 mA/cm ² , the time for the brightness to decrease to 97% of the initial brightness (LT97) was measured. The results of these measurements are shown in Table 2. The numerical values of Examples 7 to 10 are "relative lifespans" when Example 10 is set as 1.00.
From the results in Table 2, it was found that the organic electroluminescent device of the present invention in combination with a host material having a specific structure can provide a device with a particularly long life.

Although various embodiments have been described above, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the claims, and these naturally fall within the technical scope of the present invention. Understood. Further, each of the constituent elements in the above embodiments may be arbitrarily combined without departing from the spirit of the invention.

This application is a Japanese patent application filed on August 31, 2022 (Japanese patent application No. 2022-138447), a Japanese patent application filed on August 31, 2022 (Japanese patent application No. 2022-138449), and a Japanese patent application filed on October 7, 2022. It is based on the Japanese patent application filed (Japanese Patent Application No. 2022-162631) and the Japanese patent application (Japanese Patent Application No. 2022-162633) filed on October 7, 2022, the contents of which are incorporated as references in this application. .

The organic electroluminescent device of the present invention and the composition of the present invention can be suitably used, for example, in organic EL display devices and organic EL lighting.

1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode 8 Organic electroluminescent device

Claims

A material for a light-emitting layer of an organic electroluminescent device containing a light-emitting compound and an organometallic compound,
The organometallic compound has a molecular weight of 1,200 or more,
The luminescent compound is a compound represented by the following formula (1),
A material for a light-emitting layer that satisfies the following relational expression (E-1).
T1A≧T1B Formula (E-1)
(In formula (E-1),
T1A: triplet energy level (eV) of the organometallic compound
T1B: Triplet energy level (eV) of the light-emitting compound
represents. )

[In formula (1), ring Cy 1 , ring Cy 2 , ring Cy 3 and ring Cy 4 each independently represent a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle.
Ring Cy 1 , Cy 2 , Cy 3 and Cy 4 may further have a fused ring.
R represents a hydrogen atom or a substituent,
x, y, z, and w each represent the maximum number of bonds that R can bond to ring Cy 1 , ring Cy 2 , ring Cy 3 , and ring Cy 4 .
Q 11 , Q 12 , Q 21 and Q 22 represent NR, O or S.
When multiple R's exist, they may be the same or different.
When R is a substituent, adjacent R may be combined with each other or with ring Cy 1 , ring Cy 2 , ring Cy 3 and ring Cy 4 adjacent to R to form a ring. ]
The material for a light emitting layer according to claim 1, wherein the organometallic compound is represented by the following formula (201).

[Ring A201 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ring A202 represents an aromatic heterocyclic structure which may have a substituent.
R 201 and R 202 each independently have a structure represented by the above formula (202).
When a plurality of R 201 and R 202 exist, they may be the same or different.
Ar 201 and Ar 203 each independently represent an aromatic hydrocarbon ring structure that may have a substituent or an aromatic heterocyclic structure that may have a substituent.
Ar 202 is an aromatic hydrocarbon ring structure that may have a substituent, an aromatic heterocyclic structure that may have a substituent, or an aliphatic hydrocarbon structure that may have a substituent. represents.
When a plurality of Ar 201 , Ar 202 and Ar 203 exist, they may be the same or different.
* represents bonding to ring A201 or ring A202.
B 201 -L 200 -B 202 represents an anionic bidentate ligand. B 201 and B 202 each independently represent a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring, in which case B 201 and/or B 202 have a ring structure. represents.
L 200 represents a single bond or an atomic group that constitutes a bidentate ligand together with B 201 and B 202 .
When a plurality of B 201 -L 200 -B 202 exist, they may be the same or different.
i1 and i2 each independently represent an integer from 0 to 12.
i3 is an integer of 0 or more with an upper limit of the number that can be replaced by Ar 202 .
j is an integer of 0 or more with an upper limit of the number that can be replaced by Ar 201 .
k1 and k2 are each independently an integer of 0 or more, with the upper limit being the number that can be substituted into ring A201 and ring A202.
m is an integer from 1 to 3. ]
The light-emitting layer material according to claim 1, wherein the T1A is 2.10 eV or more and 2.80 eV or less.
The material for a light-emitting layer according to claim 1, wherein the light-emitting compound represented by the formula (1) is represented by the formula (2-1) or the formula (2-2).

[In formula (2-1) and formula (2-2), Q 31 and Q 32 represent O or S.
R is the same as in formula (1) above, and when a plurality of R's exist, they are independent from each other and may be the same or different.
When R is a substituent, it may combine with adjacent R's to form a ring. ]
The material for a light-emitting layer according to claim 1, wherein the light-emitting compound represented by the formula (1) is represented by the formula (2-3).

[In formula (2-3), Q 31 and Q 32 represent O or S.
R is the same as in the above formula (1), and when a plurality of R's exist, they are independent from each other and may be the same or different.
When R is a substituent, it may combine with adjacent R's to form a ring.
R' represents a hydrogen atom or a substituent, and when multiple R's exist, they are independent from each other and may be the same or different. ]
The material for a light-emitting layer according to claim 1, wherein MwA/MwB is 2.0 or more, where MwA is the molecular weight of the organometallic compound and MwB is the molecular weight of the light-emitting compound.
The light-emitting layer material according to claim 1, further comprising a host material.
The host material includes at least one selected from a compound represented by the following formula (250), a compound represented by the following formula (240), and a compound represented by the following formula (260). 7. The material for a light-emitting layer according to 7.

(In formula (250),
each W independently represents CH or N, at least one W is N,
Xa 1 , Ya 1 and Za 1 each independently represent a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a carbon atom which may have a substituent. represents a divalent aromatic heterocyclic group of number 3 to 30,
Xa 2 , Ya 2 and Za 2 are each independently a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. Represents a monovalent aromatic heterocyclic group having 3 to 30 carbon atoms,
g11, h11, and j11 each independently represent an integer from 0 to 6,
At least one of g11, h11, and j11 is an integer of 1 or more,
When g11 is 2 or more, multiple Xa 1s may be the same or different,
When h11 is 2 or more, multiple Ya 1s may be the same or different,
When g11 is 2 or more, multiple Za 1s may be the same or different,
R 31 represents a hydrogen atom or a substituent, and the four R 31s may be the same or different,
However, when g11, h11, or j11 is 0, the corresponding Xa 2 , Ya 2 , and Za 2 are not hydrogen atoms. )

(In formula (240),
Ar 611 and Ar 612 each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
R 611 and R 612 are each independently a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
n 611 and n 612 are each independently an integer of 0 to 4. )

(In formula (260),
Ar 61 to Ar 65 are each independently a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms which may have a substituent,
L 1 to L 5 are each independently a divalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms that may have a substituent,
R 60 each independently represents a substituent,
m1 to m5 each independently represent an integer from 0 to 5,
n represents an integer from 0 to 10,
a1 to a3 each independently represent an integer from 0 to 3,
However, at least one group among Ar 61 , Ar 62 , Ar 63 , Ar 64 , and at least one Ar 65 when n is 1 or more does not become a hydrogen atom. )
The light-emitting layer material according to claim 8, wherein the host material contains at least a compound represented by the formula (250).
The light-emitting layer material according to claim 8, wherein in the formula (250), -(Ya 1 ) h11 -(Ya 2 ) and -(Za 1 ) j11 -(Za 2 ) are not simultaneously unsubstituted phenyl groups. .
In the formula (250), a substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms may have, and a substituent that the aromatic heterocyclic group having 3 to 30 carbon atoms may have; The material for a light-emitting layer according to claim 8, wherein the group is selected from the following substituent group Z2, and the substituent selected from the following substituent group Z2 has no further substituent.
<Substituent group Z2>
Alkyl group, alkoxy group, aryloxy group, heteroaryloxy group, alkoxycarbonyl group, dialkylamino group, diarylamino group, arylalkylamino group, acyl group, halogen atom, haloalkyl group, alkylthio group, arylthio group, silyl group, Siloxy group, cyano group, aromatic hydrocarbon group, and aromatic heterocyclic group
The light-emitting layer material according to claim 8, wherein at least two of W in the formula (250) are N.
In the above formula (250), (Xa 1 ) g11 when g11 is 1 or more, (Ya 1 ) h11 when h11 is 1 or more, (Za 1 ) j11 when j11 is 1 or more, the above Ar 611 and Ar 612 in formula (240), (L 1 ) m1 when m1 is 1 or more, (L 2 ) m2 when m2 is 1 or more, and m3 in formula (260) above (L 3 ) m3 in the above case, (L 4 ) m4 in the case where m4 is 1 or more, and (L 5 ) m5 in the case where n is 1 or more and m5 is 1 or more are each independently expressed by the following formula (11 ) to the partial structure represented by the following formula (17), the material for a light-emitting layer according to claim 8.

(In each of formulas (11) to (17), * indicates the bonding position with the adjacent structure, or in the case of formula (250), the corresponding position when Xa 2 , Ya 2 , or Za 2 is a hydrogen atom. In the case of formula (260), a hydrogen atom represents a hydrogen atom when Ar 61 , Ar 62 , Ar 63 , Ar 64 or Ar 65 is a hydrogen atom, and at least one of the two * is adjacent (Represents the bonding position with the structure.)
In the formula (250), at least one of -(Xa 1 ) g11 -(Xa 2 ), -(Ya 1 ) h11 -(Ya 2 ), and -(Za 1 ) j11 -(Za 2 ) is as follows: The material for a light-emitting layer according to claim 8, which has any one of a partial structure or a terminal structure represented by the formula (250-1) to the following formula (250-10).

[In formulas (250-1) to (250-10), * represents the bonding position. Ar 250 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms. R 32 represents a substituent, and the structures represented by formulas (250-1) to (250-10) may further have a substituent. ]
The light-emitting layer material according to claim 8, wherein the host material contains at least a compound represented by the formula (240).
In the compound represented by the formula (240), the Ar 611 and the Ar 612 each independently have a partial structure selected from the following formulas (11) to (17) and (21) to (24), The light-emitting layer material according to claim 8.

(* represents a bonding position with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position with an adjacent structure)
The light-emitting layer material according to claim 8, wherein the host material contains at least a compound represented by the formula (260).
Claim 8, wherein one or more and three or less groups of Ar 61 , Ar 62 , and at least one Ar 65 in the formula (260) are the following formula (261) or the following formula (262). The light-emitting layer material described in .

(In formula (261) or formula (262),
The asterisk (*) represents the bonding position with formula (260),
R 101 to R 126 each independently represent a hydrogen atom or a substituent. )
The compound represented by the formula (250) was designated as (group A), the compound represented by the formula (240) was designated as (group B), and the compound represented by the formula (260) was designated as (group C). When, the host material is selected from at least one kind from each of at least two arbitrary groups among the three groups represented by the above (group A), the above (group B), and the above (group C). The material for a light-emitting layer according to claim 8, comprising at least two types of compounds.
An organic electroluminescent device having an anode, a cathode, and a light emitting layer,
the light emitting layer is provided between the anode and the cathode,
An organic electroluminescent device, wherein the light emitting layer contains the light emitting layer material according to any one of claims 1 to 19.
An organic EL display device or organic EL lighting comprising the organic electroluminescent element according to claim 20.
A composition comprising the light-emitting layer material according to any one of claims 1 to 19 and an organic solvent.
A method for manufacturing an organic electroluminescent device having an anode, a light emitting layer, and a cathode in this order on a substrate, the method comprising:
A method for manufacturing an organic electroluminescent device, comprising the step of forming the light emitting layer by a wet film forming method using the composition according to claim 22.