Composition for forming the light-emitting layer of a quantum dot light-emitting device, quantum dot light-emitting device, quantum dot display device, and quantum dot illumination.

Abstract

This invention provides a quantum dot light-emitting element that operates at low voltage, has high luminous efficiency, and a long operating life. [Solution] A composition for forming the light-emitting layer of a quantum dot light-emitting device, comprising a quantum dot, a compound represented by formula (1), and an organic solvent. TIFF2026102574000052.tif61140 (Ar 21 Ar 22 This refers to an aromatic hydrocarbon group having 6 to 30 carbon atoms, an aromatic heterocyclic group having 3 to 30 carbon atoms, or a monovalent group formed by the linkage of 2 to 7 of these groups. 21 ~R 24 (This refers to alkyl groups, aromatic hydrocarbon groups with 6 to 30 carbon atoms, aromatic heterocyclic groups with 3 to 30 carbon atoms, or monovalent groups formed by the linkage of 2 to 7 of these groups.)

Description

[Technical Field]

[0001] This invention relates to a composition for forming a light-emitting layer of a quantum dot light-emitting device, and to a quantum dot light-emitting device, a quantum dot display device, and a quantum dot illumination device using the same. [Background technology]

[0002] As a thin-film type electroluminescent device, organic electroluminescent devices using organic thin films are being developed. Organic electroluminescent devices (OLEDs) typically have a hole injection layer, a hole transport layer, an organic light-emitting layer, and an electron transport layer between the anode and cathode. Materials suitable for each of these layers are being developed, and development is progressing on the emission colors, including red, green, and blue.

[0003] In recent years, attempts have been made to cover a wider color gamut by using "quantum dots," which are inorganic light-emitting materials, in the light-emitting layer to produce sharp emission spectra for red, green, and blue light sources. Electroluminescent devices using quantum dots are also called quantum dot light-emitting devices (QD-LEDs, QLEDs).

[0004] Furthermore, quantum dot light-emitting devices are typically formed by a wet deposition method (coating method). Wet deposition has advantages such as easy scaling up of large areas, and research and development of quantum dot light-emitting devices using coating methods has been progressing. For example, while quantum dot light-emitting devices have been studied in Patent Documents 1-3 and Non-Patent Document 1, there was a desire for lower voltage operation, improved luminous efficiency, and improved operating life. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-107867 [Patent Document 2] Japanese Patent Publication No. 2020-161476 [Patent Document 3] Japanese Patent Publication No. 2020-173937 [Non-patent literature]

[0006] [Non-Patent Document 1] Nature, 2014, Vol. 515, pp. 96-99 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a quantum dot light-emitting device having a light-emitting layer containing quantum dots, exhibiting excellent device characteristics, low voltage operation, high luminous efficiency, and a long operating lifetime. [Means for solving the problem]

[0008] The gist of the present invention is as follows: [1] to [9].

[0009] [1] A composition for forming a light-emitting layer of a quantum dot light-emitting device, comprising a quantum dot, a compound represented by the following formula (1), and an organic solvent.

[0010] [ka]

[0011] (In formula (1), Ar 21 Ar 22 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. R 21 ~R 24Each independently represents a monovalent group in which 2 to 7 structures selected from an alkyl group which may have a substituent, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent and an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent are linked, e and g are each independently an integer from 0 to 4, f and h are each independently an integer from 0 to 3. )

[0012] [2] A composition for forming a light-emitting layer of a quantum dot light-emitting device, comprising a quantum dot, a compound represented by the following formula (1A), and an organic solvent.

[0013]

Chemical formula

[0014] (In formula (1A), Ar 21 , Ar 22 , R 21 ~R 24 , e, f, g, h are synonymous with Ar 21 , Ar 22 , R 21 ~R 24 , e, f, g, h in the above formula (1). )

[0015] [3] A method for manufacturing a quantum dot light-emitting device, comprising a step of applying and drying the composition for forming a light-emitting layer of the quantum dot light-emitting device according to [1] or [2] to form a light-emitting layer.

[0016] [4] A method for manufacturing a quantum dot display device, comprising the method for manufacturing a quantum dot light-emitting device according to [3].

[0017] [5] A method for manufacturing a quantum dot illumination device, comprising the method for manufacturing a quantum dot light-emitting device according to [3].

[0018] [6] Having an anode, a cathode, and a light-emitting layer provided between the anode and the cathode, A quantum dot light-emitting element, wherein the light-emitting layer comprises quantum dots and a compound represented by the following formula (1).

[0019] [ka]

[0020] (In formula (1), Ar 21 Ar 22 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. R 21 ~R 24 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted alkyl groups, optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. e and g are independent integers between 0 and 4. f and h are independent integers between 0 and 3.

[0021] [7] Having an anode, a cathode, and a light-emitting layer provided between the anode and the cathode, A quantum dot light-emitting element, wherein the light-emitting layer comprises quantum dots and a compound represented by the following formula (1A).

[0022] [ka]

[0023] (In formula (1A), Ar 21 Ar 22 , R 21 ~R 24e, f, g, h are Ar in formula (1) above. 21 Ar 22 , R 21 ~R 24 (It is synonymous with e, f, g, and h.)

[0024] A quantum dot display device comprising a quantum dot light-emitting element as described in [8] [6] or [7].

[0025] [9] [6] or [7] Quantum dot illumination, including a quantum dot light-emitting element as described above. [Effects of the Invention]

[0026] The present invention provides a quantum dot light-emitting element that exhibits excellent device characteristics, operates at low voltage, has high luminous efficiency, and has a long operating life. [Brief explanation of the drawing]

[0027] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of the structure of the quantum dot light-emitting element of the present invention. [Modes for carrying out the invention]

[0028] The following describes in detail embodiments of the present invention, including the composition for forming the light-emitting layer of a quantum dot light-emitting element, the quantum dot light-emitting element, the quantum dot display device equipped with the quantum dot light-emitting element, and the quantum dot illumination equipped with the quantum dot light-emitting element. The following description is an example (representative example) of embodiments of the present invention, and the present invention is not limited to these contents unless it exceeds the gist of the invention.

[0029] [Composition for forming the light-emitting layer of quantum dot light-emitting devices] The composition for forming the light-emitting layer of a quantum dot light-emitting device of the present invention (hereinafter referred to as "the composition for forming the light-emitting layer of the present invention") comprises a quantum dot, a compound represented by the following formula (1), and an organic solvent.

[0030] [ka]

[0031] (In formula (1), Ar 21 Ar 22 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. R 21 ~R 24 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted alkyl groups, optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. e and g are independent integers between 0 and 4. f and h are independent integers between 0 and 3.

[0032] The compound represented by formula (1) contained in the light-emitting layer forming composition of the present invention may be one type or two or more types.

[0033] In a light-emitting layer formed using the light-emitting layer-forming composition of the present invention, quantum dots function as light-emitting materials, and the compound represented by formula (1) functions as a charge-transporting material.

[0034] [Reasons why this invention is effective] The light-emitting layer forming composition of the present invention and the compound represented by formula (1) contained in the light-emitting layer of a quantum dot light-emitting device formed with this light-emitting layer forming composition have appropriate charge transport properties and HOMO levels, thereby enabling the effective generation of excited states of quantum dots. The compound represented by formula (1) has a broad HOMO due to the linkage of two carbazolyl groups at the benzene ring, resulting in moderate charge transport and HOMO level. Because an aromatic hydrocarbon group or aromatic heterocyclic group is bonded to the 9-position of the two carbazolyl groups, it exhibits excellent durability.

[0035] [Quantum dots] The present invention provides a composition for forming a light-emitting layer that contains quantum dots. Quantum dots are light-emitting semiconductor nanoparticles, typically with a diameter in the range of 1 to 20 nm.

[0036] Quantum dots are preferably composed of group II-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and combinations thereof.

[0037] Examples of group II-VI compounds include CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HeSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HeZnSe, HeZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe.

[0038] Group III-V compounds include GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs. , InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb.

[0039] Examples of group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe.

[0040] Examples of Group IV elements and Group IV compounds include Si, Ge, SiC, and SiGe. ru.

[0041] A quantum dot may have a homogeneous single structure, or a core / shell dual structure. It may also have a triple or quadruple or higher structure, such as core / shell / shell. The materials constituting the core and shell are different compounds. In this case, it is preferable that the energy band gap of the shell compound is greater than the energy band gap of the core compound. Specifically, structures such as ZnTeSe / ZnSe / ZnS, CdSe / ZnS, and InP / ZnS are preferred. Furthermore, the quantum dots may be of one type or two or more types.

[0042] [Compound represented by formula (1)] The present invention provides a composition for forming the light-emitting layer of a quantum dot light-emitting device, comprising a compound represented by the following formula (1).

[0043] [ka]

[0044] (In formula (1), Ar 21 Ar 22 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. R 21 ~R 24 Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted alkyl groups, optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. e and g are independent integers between 0 and 4. f and h are independent integers between 0 and 3.

[0045] <Ar 21 Ar 22 > In the above formula (1), Ar 21 Ar 22 As for the aromatic hydrocarbon groups having 6 to 30 carbon atoms that can be applied, monovalent groups of 6-membered rings or 2 to 5-condensed rings are preferred. Specifically, examples include monovalent groups such as benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, fluorene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, fluorantene rings, and indenofluorene rings. More preferably, the monovalent groups are benzene rings, naphthalene rings, phenanthrene rings, fluorene rings, or indenofluorene rings, more preferably, benzene rings, naphthalene rings, or fluorene rings, and most preferably, benzene rings or naphthalene rings.

[0046] In the above formula (1), Ar 21 Ar 22 As aromatic heterocyclic groups having 3 to 30 carbon atoms that can be applied, monocyclic groups of 5 or 6 membered rings, or monovalent groups of 2 to 5 fused rings are preferred. Specifically, examples include monovalent groups such as furan rings, benzofuran rings, dibenzofuran rings, thiophene rings, benzothiophene rings, dibenzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, indenocarbazole rings, pyrroloimidazole rings, pyrrolopyrazole rings, pyrrolopyrrole rings, thienopyrrole rings, thienopyrrole rings, flupyrrole rings, flufuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, cinoline rings, quinoxaline rings, perimidine rings, quinazoline rings, and quinazolinone rings. Of these, the preferred group is a thiophene ring, pyrrole ring, imidazole ring, pyridine ring, pyrimidine ring, triazine ring, quinoline ring, quinazoline ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, phenanthroline ring, or indolocarbazole ring; more preferably, it is a monovalent group of a pyridine ring, pyrimidine ring, triazine ring, quinoline ring, quinazoline ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, or indenocarbazole ring; and even more preferably, it is a monovalent group of a carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, or indenocarbazole ring.

[0047] Ar 21 Ar 22 However, when the structure selected from an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have substituents, and an aromatic heterocyclic group having 3 to 30 carbon atoms, which may have substituents, is a monovalent group with 2 to 7 units linked together, the aromatic hydrocarbon group and the aromatic heterocyclic group can be selected and combined from these monovalent groups. The number of links is preferably 2 to 5, and more preferably 3.

[0048] Ar 21 Ar 22 Examples of substituents that the aromatic hydrocarbon group and aromatic heterocyclic group may have include those listed in substituent group Z described below.

[0049] <R 21 ~R 24 > In the above equation (1), R 21 ~R 24 The alkyl groups applicable are linear, branched, or cyclic alkyl groups having typically 1 or more carbon atoms, preferably 4 or more, typically 24 or less, preferably 12 or less, more preferably 8 or less, and even more preferably 6 or less. Specifically, examples include 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, and dodecyl group. In the above equation (1), R 21 ~R 24 Specific examples of monovalent groups that can be applied to this are: Ar 21 Ar 22 This is the same as the specific example described as an application.

[0050] R 21 ~R 24 Examples of substituents that the alkyl group, aromatic hydrocarbon group, or aromatic heterocyclic group may have are those listed in substituent group Z described below.

[0051] <e、f、g、h> In formula (1), e and g are each an independent integer between 0 and 4, and f and h are each an independent integer between 0 and 3. e, f, g, and h are preferably 0 or 1 in that they have moderate charge transport properties and a HOMO level. 0 is even more preferred in that it is easy to manufacture. 1 is even more preferred in that it has high heat resistance. Furthermore, if e, f, g, and h are 2 or more, R 21 ~R 24 If there are multiple R 21 ~R 24 These elements may be identical to each other, or they may be different elements.

[0052] <Substituent group Z> The substituent group Z consists of alkyl groups, alkoxy groups, aryloxy groups, heteroaryloxy groups, alkoxycarbonyl groups, dialkylamino groups, diarylamino groups, arylalkylamino groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, silyl groups, siloxy groups, cyano groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups. These substituents may include linear, branched, or cyclic structures.

[0053] More specifically, the substituent group Z includes the following structures. For example, linear, branched, or cyclic alkyl groups having typically 1 or more carbon atoms, preferably 4 or more, typically 24 or less, preferably 12 or less, more preferably 8 or less, and even more preferably 6 or less; such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, and dodecyl groups; For example, alkoxy groups such as methoxy groups and ethoxy groups, which typically have 1 or more carbon atoms, typically 24 or fewer, and preferably 12 or fewer; For example, aryloxy groups or heteroaryloxy groups such as phenoxy groups, naphthoxy groups, and pyridyloxy groups, which typically have 4 or more carbon atoms, preferably 5 or more, typically 36 or fewer, and preferably 24 or fewer; For example, alkoxycarbonyl groups such as methoxycarbonyl groups and ethoxycarbonyl groups, which typically have 2 or more carbon atoms, typically 24 or fewer, and preferably 12 or fewer; For example, dialkylamino groups such as dimethylamino groups and diethylamino groups, which typically have 2 or more carbon atoms, typically 24 or fewer, and preferably 12 or fewer; For example, diarylamino groups such as diphenylamino groups and ditlylamino groups, which typically have 10 or more carbon atoms, preferably 12 or more, typically 36 or less, and preferably 24 or less carbon atoms; For example, arylalkylamino groups such as phenylmethylamino groups, which typically have 7 carbon atoms, typically 36 or fewer, and preferably 24 or fewer; For example, acyl groups such as acetyl groups and benzoyl groups, which typically have 2 carbon atoms, typically 24 or fewer, and preferably 12 carbon atoms; For example, halogen atoms such as fluorine atoms and chlorine atoms; For example, a haloalkyl group such as a trifluoromethyl group, which usually has 1 or more carbon atoms, usually 12 or fewer, and preferably 6 or fewer carbon atoms; For example, alkylthio groups such as methylthio groups and ethylthio groups, which typically have 1 or more carbon atoms, typically 24 or fewer, and preferably 12 or fewer carbon atoms; For example, arylthio groups such as phenylthio groups, naphthylthio groups, and pyridylthio groups, which typically have 4 or more carbon atoms, preferably 5 or more, typically 36 or fewer, and preferably 24 or fewer; For example, silyl groups such as trimethylsilyl group and triphenylsilyl group, which typically have 2 or more carbon atoms, preferably 3 or more, typically 36 or fewer, and preferably 24 or fewer; For example, siloxy groups such as trimethylsiloxy group and triphenylsiloxy group, which typically have 2 or more carbon atoms, preferably 3 or more, typically 36 or fewer, and preferably 24 or fewer; Cyano group; For example, aromatic hydrocarbon groups such as phenyl groups and naphthyl groups, which typically have 6 or more carbon atoms, typically 36 or fewer, and preferably 24 or fewer; For example, aromatic heterocyclic groups such as thienyl groups and pyridyl groups, which typically have 3 or more carbon atoms, preferably 4 or more, typically 36 or fewer, and preferably 24 or fewer.

[0054] Among the substituent group Z described above, the substituents are preferably alkyl groups, alkoxy groups, diarylamino groups, aromatic hydrocarbon groups, or aromatic heterocyclic groups. From the viewpoint of charge transport, aromatic hydrocarbon groups or aromatic heterocyclic groups are preferred as substituents, aromatic hydrocarbon groups are more preferred, and it is even more preferable for the substituent to be unsubstituted. From the viewpoint of improving solubility, alkyl groups or alkoxy groups are preferred as substituents.

[0055] Furthermore, each substituent of the substituent group Z may have further substituents. Examples of these substituents are the same as those of the substituent group Z. Preferably, each substituent that the substituent group Z may have is 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, an alkoxy group having 6 or less carbon atoms, or a phenyl group. From the viewpoint of charge transport, it is even more preferable that each substituent of the substituent group Z does not have further substituents.

[0056] <Molecular weight> The compound represented by formula (1) is a low molecular weight material, preferably with a molecular weight of 5,000 or less, more preferably 3,000 or less, particularly preferably 2,000 or less, and most preferably 1,500 or less. The lower limit of the molecular weight is usually 300 or more, preferably 350 or more, and more preferably 400 or more.

[0057] <Compound represented by formula (1A)> The compound represented by formula (1) is preferable because, due to the bonding of two carbazolyl groups at the 3,3'- positions, the HOMO and LUMO are delocalized to the two carbazolyl groups, thereby enhancing hole transport and electron transport properties and enabling the effective generation of excited states of quantum dots.

[0058] [ka]

[0059] (In formula (1A), Ar 21 Ar 22 , R 21 ~R 24 e, f, g, h are Ar in formula (1) above. 21 Ar 22 , R 21 ~R 24 (It is synonymous with e, f, g, and h.)

[0060] <Specific examples of compounds represented by formula (1)> The compounds represented by formula (1) are not particularly limited, but examples include the following compounds.

[0061] [ka]

[0062] [ka]

[0063] The light-emitting layer forming composition of the present invention may contain only one compound represented by formula (1), or it may contain two or more compounds.

[0064] [organic solvent] The organic solvent contained in the light-emitting layer forming composition of the present invention is a volatile liquid component used to form a layer containing quantum dots and a compound represented by formula (1), preferably a compound represented by formula (1A), by wet film formation.

[0065] The organic solvent is not particularly limited as long as it is an organic solvent that dissolves the compound represented by formula (1), preferably the compound represented by formula (1A), and, in the case of other charge-transporting materials described later, the other charge-transporting materials.

[0066] 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, dichlorobenzene, and trichlorobenzene; and aromatics such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether. Alicyclic ethers; aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; alicyclic ketones such as cyclohexanone, cyclooctanone, and fencone; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and so on.

[0067] Among these, alkanes, aromatic hydrocarbons, and aromatic esters are preferred from the viewpoint of viscosity and boiling point, with aromatic hydrocarbons and aromatic esters being particularly preferred.

[0068] These organic solvents may be used individually, or two or more may be used in any combination and ratio.

[0069] 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 film formation stability may decrease during wet film formation due to solvent evaporation from the light-emitting layer forming composition. If the boiling point of the organic solvent is above this range, the film formation stability may decrease due to solvent residue after wet film formation.

[0070] In particular, it is preferable to combine two or more organic solvents with boiling points of 150°C or higher from the above organic solvents, as this is thought to facilitate the formation of a more uniform coating film.

[0071] [Other charge transport materials] The light-emitting layer forming composition of the present invention may further contain other charge transport materials other than the compound represented by formula (1).

[0072] Other charge transport materials that can be used include those used as charge transport materials in organic electroluminescent devices. Examples include pyridine, carbazole, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthene, benzophenanthrene, fluorene, acetonaphthofluoranthene, coumarin, p-bis(2-phenylethenyl)benzene and their derivatives, quinacridone derivatives, DCM(4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, azabenzothioxanthene, fused aromatic ring compounds substituted with arylamino groups, and styryl derivatives substituted with arylamino groups.

[0073] These may be used individually, or two or more may be used in any combination and ratio.

[0074] Of these, naphthalene, perylene, pyrene, anthracene, chrysene, naphthacene, phenanthrene, coronene, fluoranthen, benzophenanthrene, fluorene, acetonaphthofluoranthene, and their derivatives are preferred, and anthracene derivatives are more preferred.

[0075] [Content] The quantum dot content in the light-emitting layer forming composition of the present invention is typically 0.001% by mass or more, preferably 0.01% by mass or more, and typically 30.0% by mass or less, preferably 20.0% by mass or less. The content of the compound represented by formula (1), preferably the compound represented by formula (1A), in the light-emitting layer forming composition of the present invention is usually 0.01% by mass or more, preferably 0.1% by mass or more, usually 30.0% by mass or less, and preferably 20.0% by mass or less. By setting the content of quantum dots and the compound represented by formula (1), preferably the compound represented by formula (1A), within this range, holes and electrons can be efficiently injected from adjacent layers (e.g., hole transport layer and hole blocking layer) to the light-emitting layer, thereby reducing the driving voltage. Furthermore, the quantum dot, the compound represented by formula (1), preferably the compound represented by formula (1A), may be included in the light-emitting layer-forming composition as a single type, or as a combination of two or more types.

[0076] If the light-emitting layer forming composition of the present invention contains other charge transport materials, their content 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. By setting the content of other charge transport materials in the light-emitting layer forming composition within the above range, the transportability of electrons within the light-emitting layer is improved, resulting in a lower voltage, and the balance between electrons and holes within the light-emitting layer is improved, which is thought to improve the luminescence efficiency.

[0077] Furthermore, from the viewpoint of improving luminescence efficiency, the total content of the compound represented by formula (1), preferably the compound represented by formula (1A), and other charge transport materials in the luminescent layer forming composition of the present invention is usually 10 parts by mass or less, preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, usually 0.001 parts by mass or more, preferably 0.005 parts by mass or more, and more preferably 0.01 parts by mass or more, per 1 part by mass of quantum dot.

[0078] The organic solvent content in the light-emitting layer forming composition of the present invention 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 organic solvent content is above the lower limit, it has an appropriate viscosity and the coatability is improved, and if it is below the upper limit, a uniform film is easily obtained and the film-forming properties are good.

[0079] [Other ingredients] The light-emitting layer forming composition of the present invention may optionally contain other compounds in addition to quantum dots and the above-mentioned compounds. Preferred examples of other compounds include dibutylhydroxytoluene, known as an antioxidant, and phenols such as dibutylphenol.

[0080] [Film forming method] The method for forming a light-emitting layer using the light-emitting layer-forming composition of the present invention is a wet film deposition method. A wet film deposition method is a method in which the composition is applied to form a liquid film, which is then dried to remove the organic solvent and form a light-emitting layer film. The application method may include, for example, a wet film deposition method such as spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet, nozzle printing, screen printing, gravure printing, or flexographic printing, and the coated film is dried to form the film. Among these film deposition methods, spin coating, spray coating, inkjet, and nozzle printing are preferred. When manufacturing a quantum dot display device equipped with a quantum dot light-emitting element using the light-emitting layer-forming composition of the present invention, the inkjet method or nozzle printing method is preferred, and the inkjet method is particularly preferred.

[0081] The drying method is not particularly limited, but natural drying, vacuum drying, heat drying, or vacuum drying with heating can be used as appropriate. Heat drying may be performed after natural drying or vacuum drying to further remove residual organic solvents. Vacuum drying is preferably performed by reducing the pressure to below the vapor pressure of the organic solvent contained in the luminescent layer forming composition. When heating, the heating method is not particularly limited, but heating by 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, and preferably 200°C or lower, and 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.

[0082] [Quantum dot light-emitting element] A quantum dot light-emitting device according to one aspect of the present invention includes an anode, a cathode, and a light-emitting layer (light-emitting layer in the first embodiment) formed between the anode and the cathode using the light-emitting layer forming composition of the present invention. Furthermore, another embodiment of the present invention provides a quantum dot light-emitting device having an anode, a cathode, and a light-emitting layer provided between the anode and the cathode, wherein the light-emitting layer contains quantum dots and a compound represented by formula (1).

[0083] The quantum dot light-emitting device of the present invention preferably further includes an organic layer other than the light-emitting layer as a second organic layer between the anode and the light-emitting layer. The second organic layer is more preferably a hole injection layer or a hole transport layer, and more preferably a hole transport layer. Furthermore, as described below, this second organic layer preferably contains a polymer having a triarylamine structure as a repeating unit (hereinafter, the polymer contained in this second organic layer may be referred to as the "second polymer"), and it is even more preferable that the polymer does not contain a crosslinking group. As the second polymer, a polymer containing a repeating unit represented by formula (5) is preferred, and more preferably a polymer containing a repeating unit represented by formula (2), formula (3), or formula (4) is preferred.

[0084] The second organic layer is preferably formed by a wet film deposition method using the second composition described later. The second composition is insoluble by heating after application. Therefore, the second organic layer can be suitably used for stacking quantum dot light-emitting devices.

[0085] The second organic layer included in the quantum dot light-emitting device of the present invention is described below. The structure of the quantum dot light-emitting device of the present invention will be described later.

[0086] [Second organic layer] The second organic layer preferably contains a second polymer having a triarylamine structure as a repeating unit, as a hole transport material.

[0087] [Second polymer to be used in the second organic layer] As a second polymer having a repeating triarylamine structure without crosslinking groups contained in the second organic layer, it is preferable that the triarylamine structure is included in the main chain of the polymer. The repeating unit of the triarylamine structure is represented by the following formula (5).

[0088] [ka]

[0089] (In formula (5), Ar 4 This represents an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group. Ar 5 This represents a divalent aromatic hydrocarbon group which may have substituents other than a crosslinking group, a divalent aromatic heterocyclic group which may have substituents other than a crosslinking group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked directly or via a linking group. Ar 4 and Ar 5 (These may form a ring via single bonds or linking groups.)

[0090] (Ar 4 ) In the repeating unit represented by the above formula (5), Ar 4 This represents an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group.

[0091] The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms, and specifically includes monovalent groups of 6-membered rings or 2- to 5-fused rings, such as benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, and fluorene rings, or groups in which multiple such groups are linked. For example, "monovalent group of a benzene ring" means "a benzene ring with a monovalent free valency," i.e., a phenyl group.

[0092] The aromatic heterocyclic group is preferably one with 3 to 60 carbon atoms, specifically a 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, phlopyrrole ring, phlofuran ring, thienofuran ring, benzo Examples include monovalent groups of 5-6 membered rings or 2-4 fused rings, such as soxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, and azulene rings, or groups formed by linking multiple such rings.

[0093] Ar 4 From the standpoint of excellent charge transport properties and durability, aromatic hydrocarbon groups which may have substituents other than the crosslinking group are preferred, and among these, monovalent groups of benzene rings or fluorene rings which may have substituents other than the crosslinking group are more preferred, i.e., phenyl groups or fluorenyl groups which may have substituents other than the crosslinking group are more preferred, fluorenyl groups which may have substituents other than the crosslinking group are even more preferred, and 2-fluorenyl groups which may have substituents other than the crosslinking group are particularly preferred.

[0094] Ar 4Other substituents besides the crosslinking groups that the aromatic hydrocarbon group and aromatic heterocyclic group may have are not particularly limited, as long as they do not significantly reduce the properties of the polymer. Preferably, the substituents are groups selected from the substituent group Z, with alkyl groups, alkoxy groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups being more preferred, and alkyl groups being even more preferred.

[0095] Ar 4 From the viewpoint of solubility in the coating solvent, a fluorenyl group substituted with an alkyl group having 1 to 24 carbon atoms is preferred, and a 2-fluorenyl group substituted with an alkyl group having 4 to 12 carbon atoms is particularly preferred. Furthermore, a 9-alkyl-2-fluorenyl group in which the 9-position of the 2-fluorenyl group is substituted with an alkyl group is preferred, and a 9,9'-dialkyl-2-fluorenyl group substituted with two alkyl groups is particularly preferred.

[0096] The fluorenyl group in which at least one of the 9th and 9' positions is substituted with an alkyl group tends to have improved solubility in solvents and durability of the fluorene ring. Furthermore, the fluorenyl group in which both the 9th and 9' positions are substituted with alkyl groups tends to have even improved solubility in solvents and durability of the fluorene ring.

[0097] Also, Ar 4 From the viewpoint of solubility in the coating solvent, it is also preferable that it be a spirobifluorenyl group.

[0098] (Other preferred Ar 4 ) Ar in the repeating unit represented by the above formula (5) 4 It is also preferable that at least one of the groups is represented by the following formula (10). This is because, in the two carbazole structures in formula (10), the LUMO is distributed between the nitrogen atoms of each other in the aromatic hydrocarbon group or aromatic heterocyclic group, which suppresses the influence on the main chain amine in formula (5) and improves the durability of the main chain amine against electrons and excitons.

[0099] [ka]

[0100] (In formula (10), Ar 11 and Ar 12 are each independently a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent, Ar 13 ~Ar 15 are each independently a hydrogen atom or a substituent. * represents the bonding position to the nitrogen atom in formula (2).)

[0101] (Ar 13 ~Ar 15 ) Ar 13 ~Ar 15 each independently represents a hydrogen atom or a substituent. When Ar 13 ~Ar 15 is a substituent, the substituent is not particularly limited, but is preferably an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. The preferred structure is the same as the group exemplified for the above Ar 4 .

[0102] When Ar 13 ~Ar 15 is a substituent, it is preferable from the viewpoint of durability improvement that Ar 13 ~Ar 15 is bonded to the 3-position or 6-position of each carbazole structure.

[0103] From the viewpoints of ease of synthesis and charge transport property, Ar 13 ~Ar 15 is preferably a hydrogen atom.

[0104] Ar 13 ~Ar 15From the viewpoints of improving durability and charge transportability, it is preferably an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, and more preferably an aromatic hydrocarbon group which may have a substituent.

[0105] Ar 13 ~Ar 15 When Ar~Ar is an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent, the substituents are the same as those listed in the substituent group Z, the preferred substituents are the same, and the substituents which these substituents may further have are also the same.

[0106] (Ar 12 ) Ar 12 is a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent.

[0107] The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms, more preferably 10 to 50 carbon atoms, and particularly preferably 12 to 40 carbon atoms. Specific examples of the aromatic hydrocarbon group include a monocyclic 6-membered ring such as a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, fluorene ring, etc., or a divalent group of a 2- to 5-fused ring or a group formed by linking a plurality of these. When a plurality of these are linked, it is preferably a group in which the linked divalent aromatic hydrocarbon groups are conjugated.

[0108] The aromatic heterocyclic group is preferably one having 3 to 60 carbon atoms, specifically a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienopyrrole ring, a phlopyrrole ring, a phlofuran ring, a thienofuran ring, or a benzoiso ring. Examples include oxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenanthridine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, azulene rings, and other 5- or 6-membered monocyclic rings or 2- to 4-fused rings with divalent groups, or groups formed by linking multiple such rings.

[0109] The substituents that these aromatic hydrocarbon groups or aromatic heterocyclic groups may have include alkyl groups, aralkyl groups, and aromatic hydrocarbon groups of substituent group Z. Due to the steric effect of the substituents, Ar 12 If a twist in the structure occurs, it is preferable to have no substituents, and the steric effect of the substituents is Ar 12 If no twisting of the structure occurs, it is preferable to have substituents.

[0110] Ar 12 Specific preferred groups are divalent groups of a benzene ring, naphthalene ring, anthracene ring, or fluorene ring, or groups in which multiple such groups are linked; more preferably, divalent groups of a benzene ring, or groups in which multiple such groups are linked; particularly preferably, a 1,4-phenylene group in which a benzene ring is linked at the 1,4 positions with divalentity; a 2,7-fluorenylene group in which a fluorene ring is linked at the 2,7 positions with divalentity; or a group in which multiple such groups are linked; and most preferably, a group containing "1,4-phenylene group-2,7-fluorenylene group-1,4-phenylene group-".

[0111] In these preferred structures, the phenylene group has no substituents other than at the linking position, which is due to the steric effect of substituents on Ar 12It is preferable that no twisting occurs. Furthermore, it is preferable for the fluorenylene group to have substituents at the 9,9' position, from the viewpoint of improving solubility and the durability of the fluorene structure.

[0112] (Ar 11 ) Ar 11 Ar is a divalent group that links to the nitrogen atom of the amine in the main chain in formula (10). 11 This is a divalent aromatic hydrocarbon group which may have substituents or a divalent aromatic heterocyclic group which may have substituents.

[0113] Ar 11 The aromatic hydrocarbon group preferably has 6 to 60 carbon atoms, more preferably 10 to 50 carbon atoms, and particularly preferably 12 to 40 carbon atoms. Specifically, the aromatic hydrocarbon group may be a 6-membered monocyclic or 2- to 5-fused ring, or a group formed by linking multiple such rings, such as a benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluorantene ring, or fluorene ring.

[0114] Ar 11 The aromatic heterocyclic group is preferably one having 3 to 60 carbon atoms. Specifically, examples include furan rings, benzofuran rings, thiophene rings, benzothiophene rings, pyrrole rings, pyrazole rings, imidazole rings, oxadiazole rings, indole rings, carbazole rings, pyrroloimidazole rings, pyrrolopyrrole rings, thienopyrrole rings, thienopyrrole rings, phlopyrrole rings, phlofuran rings, thienofuran rings, benzoisoxazole rings, benzoisothiazole rings, benzimidazole rings, pyridine rings, pyrazine rings, pyridazine rings, pyrimidine rings, triazine rings, quinoline rings, isoquinoline rings, sinnoline rings, quinoxaline rings, phenantholidine rings, benzimidazole rings, perimidine rings, quinazoline rings, quinazolinone rings, azulene rings, and other groups consisting of a 5- or 6-membered monocyclic ring or a 2- to 4-fused ring, or a group in which multiple such rings are linked.

[0115] The substituents that these aromatic hydrocarbon groups or aromatic heterocyclic groups may have include alkyl groups, aralkyl groups, and aromatic hydrocarbon groups of the substituent group Z.

[0116] When multiple divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups are linked together, it is preferable that the linked divalent aromatic hydrocarbon groups are bonded in such a way that they are not conjugated. Specifically, it is preferable that the group includes a 1,3-phenylene group or a group having substituents that form a twisted structure due to the steric effect of the substituents.

[0117] (Ar 5 ) Ar 5 The aromatic hydrocarbon group in this is Ar (5) 4 Examples include groups similar to the above but with a divalent valency. Also, Ar 5 The aromatic hydrocarbon group and the substituents that the aromatic hydrocarbon group may have are preferably the same as those of substituent group Z.

[0118] (crosslinking group) The second polymer used in the second organic layer does not have crosslinking groups. Here, a crosslinking group refers to a group that, upon irradiation with heat and / or active energy rays, reacts with other crosslinking groups located in its vicinity to form a new chemical bond. In this case, the reacting group may be the same as the crosslinking group or a different group.

[0119] Examples of crosslinking groups include groups containing alkenyl groups, groups containing conjugated diene structures, groups containing alkynyl groups, groups containing oxirane structures, groups containing oxetane structures, groups containing aziridine structures, azide groups, groups containing maleic anhydride structures, groups containing alkenyl groups bonded to aromatic rings, and cyclobutene rings fused to aromatic rings. Specific examples of crosslinking groups include, for example, groups selected from the following crosslinking group group T.

[0120] (Bridging group T) [ka]

[0121] In the above-mentioned group of bridged structures T, R XL n represents a methylene group, an oxygen atom, or a sulfur atom. XL This represents an integer from 0 to 5. XL If there are multiple instances, they may be the same or different, n XL If multiple such groups exist, they may be identical or different. *1 represents the bonding position. These bridging groups may have substituents.

[0122] Below, we will explain in detail the "repeating unit represented by formula (2)", the "repeating unit represented by formula (3)", and the "repeating unit represented by formula (4)" as more preferable repeating units than the one represented by formula (5) above.

[0123] <Repeating unit represented by equation (2)> [ka]

[0124] (In formula (2), Ar 1 This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group. X is -C(R 7 )(R 8 )-,-N(R 9 )- or -C(R 11 )(R 12 )-C(R 13 )(R 14 )- and, R 1 and R 2 Each of these is an alkyl group which may have substituents other than a crosslinking group, R 7 ~R 9 and R 11~R 14 Each of these is independently a hydrogen atom, an alkyl group which may have substituents other than a crosslinking group, an aralkyl group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group. a and b are independent integers between 0 and 4. c is an integer between 1 and 3. d is an integer between 0 and 4. R 1 If there are multiple R 1 They may be the same or different. R 2 If there are multiple R 2 They may be the same or different.

[0125] (R 1 , R 2 ) R in the repeating unit represented by the above formula (2) 1 and R 2 Each of these is an alkyl group that may have substituents other than a crosslinking group.

[0126] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but to maintain the solubility of the second polymer, it is preferably 1 or more, preferably 8 or less, more preferably 6 or less, and even more preferably 3 or less. The alkyl group is more preferably a methyl group or an ethyl group.

[0127] R 1 If there are multiple R 1 They may be the same or different, R 2 If there are multiple R 2 They may be the same or different. Since the charge can be uniformly distributed around the nitrogen atom and it is also easy to synthesize, all R 1 and R 2 It is preferable that they are the same group.

[0128] (R 7 ~R9 and R 11 ~R 14 ) R 7 ~R 9 and R 11 ~R 14 Each of these is independently a hydrogen atom, an alkyl group which may have substituents other than a bridging group, an aralkyl group which may have substituents other than a bridging group, or an aromatic hydrocarbon group which may have substituents other than a bridging group.

[0129] The alkyl group is not particularly limited, but it is preferable that it has 1 or more carbon atoms, preferably 24 or fewer, more preferably 8 or fewer, and even more preferably 6 or fewer, as it tends to improve the solubility of the second polymer. The alkyl group may also have a linear, branched, or cyclic structure.

[0130] Examples of the alkyl group include 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, n-octyl group, cyclohexyl group, dodecyl group, and the like.

[0131] The aralkyl group is not particularly limited, but it tends to improve the solubility of the second polymer, so it is preferable that it has 5 or more carbon atoms, preferably 60 or fewer, and more preferably 40 or fewer.

[0132] Examples of the aralkyl group include 1,1-dimethyl-1-phenylmethyl group, 1,1-di(n-butyl)-1-phenylmethyl group, 1,1-di(n-hexyl)-1-phenylmethyl group, 1,1-di(n-octyl)-1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1-n-heptyl group, 8-phenyl-1-n-octyl group, and 4-phenylcyclohexyl group.

[0133] The aromatic hydrocarbon group is not particularly limited, but it is preferable that it has 6 or more carbon atoms, preferably 60 or fewer, and more preferably 30 or fewer, as it tends to improve the solubility of the second polymer.

[0134] Examples of the aromatic hydrocarbon group include monovalent groups of 6-membered rings or 2- to 5-fused rings, such as benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, perylene rings, tetracene rings, pyrene rings, benzpyrene rings, chrysene rings, triphenylene rings, acenaphthene rings, fluorantene rings, and fluorene rings, or groups in which multiple such groups are linked together.

[0135] From the viewpoint of improving charge transport and durability, R 7 and R 8 R is preferably a methyl group or an aromatic hydrocarbon group. 7 and R 8 It is more preferably a methyl group, R 9 It is more preferable that it be a phenyl group.

[0136] R 1 , R 2 The alkyl group, R 7 ~R 9 and R 11 ~R 14 The alkyl group, aralkyl group, and aromatic hydrocarbon group may have substituents other than the crosslinking group. The substituents other than the crosslinking group are as follows: 7 ~R 9 and R 11 ~R 14 The groups listed above are preferred alkyl groups, aralkyl groups, and aromatic hydrocarbon groups.

[0137] R 1 , R 2 The alkyl group, R 7 ~R 9 and R 11 ~R 14 From the viewpoint of lowering the voltage, it is most preferable that the alkyl group, aralkyl group, and aromatic hydrocarbon group in the given molecule are free of substituents.

[0138] (a, b, c, and d) In the repeating unit represented by formula (2) above, a and b are each independent integers between 0 and 4. It is preferable that a + b is 1 or greater, and more preferably that a and b are each 2 or less, and more preferably that both a and b are 1.

[0139] When a+b is 1 or greater, the aromatic rings of the main chain are twisted due to steric hindrance, resulting in excellent solubility of the second polymer in the solvent, while the coating film formed by the wet deposition method and heat-treated tends to be highly insoluble in the solvent. Therefore, when a+b is 1 or greater, if another organic layer (e.g., an emissive layer) is formed on this coating film by the wet deposition method, the elution of the second polymer into the emissive layer-forming composition of the present invention, which contains an organic solvent, is suppressed. As a result, the impact on the formed emissive layer is reduced, and the operating life of the quantum dot light-emitting device is expected to be further extended.

[0140] In the repeating unit represented by formula (2) above, c is an integer from 1 to 3, and d is an integer from 0 to 4. Preferably, c and d are each 2 or less, more preferably c and d are equal, and particularly preferably both c and d are 1, or both c and d are 2.

[0141] If both c and d in the repeating unit represented by formula (2) above are 1, or if both c and d are 2, and both a and b are 2 or 1, then R 1 and R 2 It is most preferable that they are joined in positions symmetrical to each other.

[0142] Here, R 1 and R 2 The bond between them in symmetrical positions means that, relative to the fluorene ring, carbazole ring, or 9,10-dihydrophenanthrene derivative structure in formula (2), R 1 and R 2 This refers to the symmetrical positioning of the bonds. In this case, a 180-degree rotation around the main chain axis is considered to result in the same structure.

[0143] (Ar1 ) In the repeating unit represented by the above formula (2), Ar 1 This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group.

[0144] As a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group, the Ar 4 Examples similar to those in the case above include substituents other than the crosslinking group and preferred structures as described above. 4 The same examples as in the case of [this case] can be cited.

[0145] (Other preferred Ar 1 ) Ar in the repeating unit represented by the above formula (2) 1 It is more preferable that at least one of the elements is a group represented by formula (10).

[0146] (X) In equation (2) above, X is -C(R) because of its high stability during charge transport. 7 )(R 8 )- or -N(R 9 )- is preferred, -C(R 7 )(R 8 ) - is more preferable.

[0147] Furthermore, in a polymer containing repeating units represented by the above formula (2), Ar 1 , R 1 , R 2When there are multiple Xs, they may be the same or different. Preferably, the polymer contains a plurality of repeating units in which the repeating unit represented by the formula (2) has the same structure. In this case, since the polymer contains a plurality of repeating units having the same structure, the HOMO and LUMO of the repeating units become the same, so that charges do not concentrate on a specific shallow level to form traps, and it is considered that the charge transport property is excellent.

[0148] (Preferred repeating unit) The repeating unit represented by the above formula (2) is particularly preferably a repeating unit represented by any one of the following formulas (2-1) to (2-4).

[0149]

Chemical formula

[0150] In the above formula, R 1 and R 2 are the same, and R 1 and R 2 are bonded to each other at symmetrical positions.

[0151] <Specific examples of the main chain of the repeating unit represented by the formula (2)> The main chain structure excluding the nitrogen atom in the above formula (2) is not particularly limited, and examples thereof include the following structures.

[0152]

Chemical formula

[0153]

Chemical formula

[0154]

Chemical formula

[0155]

Chemical formula

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] <Content of repeating units represented by formula (2)> In the second polymer contained in the second organic layer, the content of the repeating unit represented by formula (2) is not particularly limited, but the repeating unit represented by formula (2) is usually contained in the second polymer in an amount of 10 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more.

[0160] The second polymer contained in the second organic layer may consist only of repeating units represented by formula (2), but may also contain repeating units other than those represented by formula (2) in order to balance the various performance characteristics when used as a quantum dot light-emitting device. In that case, the content of repeating units represented by formula (2) in the second polymer is usually 99 mol% or less, preferably 95 mol% or less.

[0161] <Terminal group> In this specification, the terminal group refers to the structure of the terminal portion of the second polymer formed by the end-capping agent used at the end of the polymerization of the second polymer. In the second organic layer, the terminal group of the second polymer containing the repeating unit represented by the formula (2) is preferably a hydrocarbon group. From the viewpoint of charge transport properties, the hydrocarbon group is preferably a hydrocarbon group having 1 or more and 60 or less carbon atoms, more preferably 1 or more and 40 or less carbon atoms, and even more preferably 1 or more and 30 or less carbon atoms.

[0162] Examples of the hydrocarbon group include linear, branched, or cyclic alkyl groups such as 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., having usually 1 or more carbon atoms, preferably 4 or more carbon atoms, usually 24 or less carbon atoms, and preferably 12 or less carbon atoms; linear, branched, or cyclic alkenyl groups such as vinyl group, etc., having usually 2 or more and 24 or less carbon atoms, preferably 12 or less carbon atoms; linear or branched alkynyl groups such as ethynyl group, etc., having usually 2 or more and 24 or less carbon atoms, preferably 12 or less carbon atoms; aromatic hydrocarbon groups such as phenyl group, naphthyl group, etc., having usually 6 or more and 36 or less carbon atoms, preferably 24 or less carbon atoms.

[0163] These hydrocarbon groups may further have substituents, and the substituents that may further be present are preferably alkyl groups or aromatic hydrocarbon groups. When there are a plurality of these substituents that may further be present, they may be bonded to each other to form a ring.

[0164] From the viewpoints of charge transport properties and durability, the terminal group is preferably an alkyl group or an aromatic hydrocarbon group, and more preferably an aromatic hydrocarbon group.

[0165] <Repeating unit represented by formula (3)>

Chemical formula

[0166] (In formula (3), Ar 2 This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group. R 3 and R 6 Each of these is an alkyl group which may have substituents other than a crosslinking group, R 4 and R 5 Each of these is independently an alkyl group which may have substituents other than the crosslinking group, an alkoxy group which may have substituents other than the crosslinking group, or an aralkyl group which may have substituents other than the crosslinking group. l is either 0 or 1. m is either 1 or 2. k is either 0 or 1. p is either 0 or 1, q is either 0 or 1.

[0167] (R 3 , R 6 ) R in the repeating unit represented by the above formula (3) 3 and R 6 Each of these is an alkyl group that may have substituents other than a crosslinking group. As the alkyl group, R in formula (2) above 1 and R 2 Similar examples include substituents that may be present and preferred structures of R. 1 and R 2 Similar examples include the above.

[0168] (R 4 , R 5 ) R in the repeating unit represented by the above formula (3) 4 and R 5Each of these is independently an alkyl group which may have substituents other than the crosslinking group, an alkoxy group which may have substituents other than the crosslinking group, or an aralkyl group which may have substituents other than the crosslinking group.

[0169] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but it is preferably 1 or more, preferably 24 or less, more preferably 8 or less, and even more preferably 6 or less, as this tends to improve the solubility of the polymer.

[0170] Examples of the alkyl group include 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, n-octyl group, cyclohexyl group, dodecyl group, and the like.

[0171] The alkoxy group is not particularly limited, and is an alkoxy group (-OR 10 ) of R 10 The alkyl group represented by may have a linear, branched, or cyclic structure, and since it tends to improve the solubility of the polymer, it is preferably one or more carbon atoms, preferably 24 or fewer, and more preferably 12 or fewer.

[0172] Examples of such alkoxy groups include methoxy, ethoxy, n-propoxy, n-butoxy, hexyloxy, 1-methylpentyloxy, and cyclohexyloxy groups.

[0173] The aralkyl group is not particularly limited, but it is preferable to have 5 or more carbon atoms, preferably 60 or fewer, and more preferably 40 or fewer, as it tends to improve the solubility of the polymer.

[0174] Examples of such aralkyl groups include 1,1-dimethyl-1-phenylmethyl group, 1,1-di(n-butyl)-1-phenylmethyl group, 1,1-di(n-hexyl)-1-phenylmethyl group, 1,1-di(n-octyl)-1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1-n-heptyl group, 8-phenyl-1-n-octyl group, and 4-phenylcyclohexyl group.

[0175] (l, m, and k) l represents 0 or 1, and k represents 0 or 1.

[0176] l and k are independent of each other, and l+k is preferably 1 or more, more preferably 1 or 2, and even more preferably 2. When l+k is within the above range, the solubility of the second polymer contained in the second organic layer is increased, and precipitation from the second composition containing the polymer tends to be suppressed.

[0177] m represents either 1 or 2, and is preferably 1 because the quantum dot light-emitting element of the present invention can be driven at a low voltage, and hole injection capability, transport capability, and durability tend to be improved.

[0178] (p and q) p represents 0 or 1, and q represents 0 or 1. When l=k=1, p and q cannot be 0 at the same time. The fact that p and q cannot be 0 at the same time tends to increase the solubility of the second polymer contained in the second organic layer and suppress precipitation from the second composition containing the polymer. Furthermore, for the same reasons as in a and b above, it is considered preferable that the driving life of the quantum dot light-emitting element is further extended when p+q is 1 or greater.

[0179] (Ar 2 ) In the repeating unit represented by the above formula (3), Ar 2This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group.

[0180] As a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than the crosslinking group, an aromatic heterocyclic group which may have substituents other than the crosslinking group, or an aromatic hydrocarbon group which may have substituents other than the crosslinking group and an aromatic heterocyclic group which may have substituents other than the crosslinking group, the Ar in formula (2) is 1 Examples similar to those in the case above include substituents other than the crosslinking group and preferred structures as described above. 1 The same examples as in the case of [this case] can be cited.

[0181] Also, Ar 2 From the viewpoint of solubility in the coating solvent, it is also preferable that it be a spirobifluorenyl group.

[0182] In particular, Ar 2 The group is preferably represented by the following formula (15) or the following formula (16).

[0183] [ka]

[0184] (In formulas (15) and (16), * represents the bonding position with the nitrogen atom in formula (3).)

[0185] (Other preferred Ar 2 ) The aforementioned Ar 1 Similarly, Ar 2 Preferably, at least one of them is a group represented by formula (10). 2 When at least one of the groups is a group represented by formula (10), the preferred structure of formula (10) and the substituents it may have are the Ar 1This is the same as when at least one of them is a group represented by formula (10).

[0186] <Specific example of a repeating main chain represented by formula (3)> The main chain structure excluding the nitrogen atom in formula (3) is not particularly limited, but examples include the following structures.

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] <Content of repeating units represented by formula (3)> In the second polymer contained in the second organic layer, the content of the repeating unit represented by formula (3) is not particularly limited, but the repeating unit represented by formula (3) is usually contained in the second polymer in an amount of 10 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and particularly preferably 50 mol% or more.

[0196] The second polymer contained in the second organic layer may consist only of repeating units represented by formula (3), but may also contain repeating units other than those represented by formula (3) in order to balance the various performance characteristics when used as a quantum dot light-emitting device. In that case, the content of repeating units represented by formula (3) in the second polymer is usually 99 mol% or less, preferably 95 mol% or less.

[0197] <Terminal group> In the second polymer contained in the second organic layer, the terminal groups of the second polymer containing the repeating unit represented by formula (3) are preferably hydrocarbon groups, similar to the terminal groups of the second polymer containing the repeating unit represented by formula (2). Preferred hydrocarbon groups and optional substituents are the same as those of the terminal groups of the polymer containing the repeating unit represented by formula (2).

[0198] [Repeating unit represented by formula (4)] [ka]

[0199] (In formula (4), Ar 3 This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group. Ar 41This is a divalent aromatic hydrocarbon group which may have substituents other than a crosslinking group, a divalent aromatic heterocyclic group which may have substituents other than a crosslinking group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is directly or via a linking group, R 41 and R 42 Each of these is an alkyl group which may have substituents other than a crosslinking group, t is either 1 or 2. u is either 0 or 1, r and s are independent integers between 0 and 4.

[0200] (R 41 , R 42 ) R in the repeating unit represented by the above formula (4) 41 , R 42 Each of these is an alkyl group that may have substituents other than a crosslinking group.

[0201] The alkyl group is a linear, branched, or cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but to maintain the solubility of the polymer, it is preferable to have 1 or more carbon atoms, preferably 10 or fewer, more preferably 8 or fewer, and even more preferably 6 or fewer. The alkyl group is even more preferably a methyl group or a hexyl group.

[0202] R 41 and R 42 If there are multiple R in the repeating unit represented by the above formula (4), then multiple R 41 and R 42 They may be the same or different.

[0203] (r, s, t, and u) In the repeating unit represented by equation (4), r and s are each independent integers between 0 and 4. Preferably, r+s is 1 or greater, and further preferably, r and s are each 2 or less. When r+s is 1 or greater, the driving lifetime of the quantum dot light-emitting element is considered to be even longer for the same reasons as a and b in equation (2).

[0204] In the repeating unit represented by formula (4) above, t is 1 or 2, and u is 0 or 1. Preferably, t is 1, and preferably u is 1.

[0205] (Ar 3 ) In the repeating unit represented by the above formula (4), Ar 3 This is a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group.

[0206] As a group formed by linking multiple groups selected from an aromatic hydrocarbon group which may have substituents other than a crosslinking group, an aromatic heterocyclic group which may have substituents other than a crosslinking group, or an aromatic hydrocarbon group which may have substituents other than a crosslinking group and an aromatic heterocyclic group which may have substituents other than a crosslinking group, the Ar in formula (5) is 4 Examples similar to those in the case above include substituents other than the crosslinking group and preferred structures as described above. 4 The same examples as in the case of [this case] can be cited.

[0207] (Ar 41 ) Ar 41 This refers to a divalent aromatic hydrocarbon group which may have substituents other than a crosslinking group, a divalent aromatic heterocyclic group which may have substituents other than a crosslinking group, or a divalent group in which at least one group selected from the group consisting of the divalent aromatic hydrocarbon group and the divalent aromatic heterocyclic group is linked directly or via a linking group.

[0208] Ar 41 The aromatic hydrocarbon group in and the aromatic hydrocarbon group in formula (5) is Ar 5 Similar groups can be cited. Furthermore, the aromatic hydrocarbon group and the substituents that the aromatic hydrocarbon group may have are preferably the same as those in substituent group Z, and it is even more preferable that the substituents that may be present are the same as those in substituent group Z.

[0209] <Specific examples of repeating units represented by equation (4)> The repeating unit represented by equation (4) is not particularly limited, but for example, the following structure can be considered.

[0210] [ka]

[0211] <Content of repeating units represented by formula (4)> In the second polymer contained in the second organic layer, the content of the repeating unit represented by formula (4) is not particularly limited, but the repeating unit represented by formula (4) is usually contained in the second polymer in an amount of 10 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more, and particularly preferably 50 mol% or more.

[0212] The second polymer contained in the second organic layer may consist only of repeating units represented by formula (4), but may also contain repeating units other than those represented by formula (4) in order to balance the various performance characteristics when used as a quantum dot light-emitting device. In that case, the content of repeating units represented by formula (4) in the second polymer is usually 99 mol% or less, preferably 95 mol% or less.

[0213] <Terminal group> In the second polymer contained in the second organic layer, the terminal groups of the polymer containing the repeating unit represented by formula (4) are preferably hydrocarbon groups, similar to the terminal groups of the second polymer containing the repeating unit represented by formula (2). Preferred hydrocarbon groups and optional substituents are also the same as those of the terminal groups of the polymer containing the repeating unit represented by formula (2).

[0214] [Molecular weight of the second polymer] The molecular weight of the second polymer contained in the second organic layer is described below.

[0215] The weight-average molecular weight (Mw) of the second polymer containing the repeating unit represented by formula (2) is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, even more preferably 200,000 or less, and particularly preferably 100,000 or less. Furthermore, the weight-average molecular weight is usually 2,500 or more, preferably 5,000 or more, more preferably 10,000 or more, even more preferably 15,000 or more, and particularly preferably 17,000 or more.

[0216] When the weight-average molecular weight of the second polymer containing the repeating unit represented by formula (2) is below the above upper limit, solubility in the solvent is obtained, and the film-forming properties tend to be excellent. Furthermore, when the weight-average molecular weight of the polymer is above the above lower limit, the decrease in the glass transition temperature, melting point, and vaporization temperature of the polymer is suppressed, and the heat resistance may be improved.

[0217] Furthermore, the number-average molecular weight (Mn) of the second polymer containing the repeating unit represented by formula (2) is usually 2,500,000 or less, preferably 750,000 or less, more preferably 400,000 or less, and particularly preferably 100,000 or less. Also, the number-average molecular weight is usually 2,000 or more, preferably 4,000 or more, more preferably 6,000 or more, and even more preferably 8,000 or more.

[0218] Furthermore, the degree of dispersion (Mw / Mn) in the second polymer containing the repeating unit represented by formula (2) is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. Since a smaller degree of dispersion is better, the lower limit is ideally 1. When the degree of dispersion of the polymer is below the above upper limit, it is easy to purify and has good solubility in solvents and charge transport ability.

[0219] The weight-average molecular weight (Mw) of the second polymer containing the repeating unit represented by formula (3) or formula (4) is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 17,000 or more. Furthermore, the weight-average molecular weight is preferably 2,000,000 or less, more preferably 1,000,000 or less, and particularly preferably 100,000 or less.

[0220] When the weight-average molecular weight of the second polymer containing the repeating unit represented by formula (3) or formula (4) is below the above upper limit, the increase in molecular weight of impurities is suppressed, and purification tends to be easy. Furthermore, when the weight-average molecular weight of the polymer is above the above lower limit, the decrease in glass transition temperature, melting point, vaporization temperature, etc. is suppressed, and heat resistance tends to improve.

[0221] Furthermore, the number-average molecular weight (Mn) of the second polymer containing the repeating unit represented by formula (3) or formula (4) is preferably 1,000,000 or less, more preferably 800,000 or less, and even more preferably 500,000 or less. In addition, the number-average molecular weight is preferably 4,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more.

[0222] Furthermore, the degree of dispersion (Mw / Mn) of the second polymer containing the repeating unit represented by formula (3) or formula (4) is preferably 3.5 or less, more preferably 3.0 or less, even more preferably 2.4 or less, particularly preferably 2.1 or less, and most preferably 2 or less. In addition, the degree of dispersion of the polymer is preferably 1 or more, more preferably 1.1 or more, and even more preferably 1.2 or more. Having the degree of dispersion of the polymer below the above upper limit makes purification easier and tends to suppress the decrease in solubility in the solvent and the decrease in charge transport capacity.

[0223] Typically, the weight-average molecular weight and number-average molecular weight of polymers are determined by SEC (size exclusion chromatography) measurement. In SEC measurement, components with higher molecular weights have shorter elution times, while components with lower molecular weights have longer elution times. However, by using a calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the weight-average molecular weight and number-average molecular weight can be calculated by converting the sample's elution time to molecular weight.

[0224] [Specific example] Specific examples of a second polymer containing repeating units represented by formula (2) are shown below, but the second polymer used in the present invention is not limited to these. The numbers in the chemical formulas represent the molar ratio of repeating units, where n represents the number of repeating units.

[0225] These second polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and are not limited to the order of monomer arrangement.

[0226] [ka]

[0227] A second polymer containing repeating units represented by formula (3), and Ar 2Specific examples of a second polymer having the structure represented by formula (10) are shown below, but the second polymer used in the present invention is not limited to these. The numbers in the chemical formulas represent the molar ratio of repeating units. n represents the number of repeats.

[0228] These second polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and the order of monomer arrangement is not limited.

[0229] [ka]

[0230] [ka]

[0231] [ka]

[0232] Specific examples of a second polymer containing repeating units represented by formula (4) are shown below, but the second polymer used in the present invention is not limited to these. The numbers in the chemical formulas represent the molar ratio of the repeating units, where n represents the number of repeating units.

[0233] These second polymers may be random copolymers, alternating copolymers, block copolymers, or graft copolymers, and are not limited to the order of monomer arrangement.

[0234] [ka]

[0235] [ka]

[0236] <Method for producing the second polymer> The method for producing the second polymer contained in the second organic layer is not particularly limited and is arbitrary. Examples include polymerization by the Suzuki reaction, polymerization by the Grignard reaction, polymerization by the Yamamoto reaction, polymerization by the Ullmann reaction, polymerization by the Buchwald-Hartwig reaction, and so on.

[0237] In the polymerization methods by the Ullmann reaction and the Buchwald-Hartwig reaction, for example, a second polymer containing the repeating unit represented by formula (2) is synthesized by reacting an aryl dihalide represented by the following formula (2a) (where Z represents a halogen atom such as I, Br, Cl, or F) with a primary aminoaryl represented by the following formula (2b).

[0238] [ka]

[0239] (In the above reaction equation, Ar 1 , R 1 , R 2 X, a~d are equivalent to those in equation (2) above.

[0240] Furthermore, in the polymerization methods by the Ullmann reaction and the Buchwald-Hartwig reaction, for example, a polymer containing the repeating unit represented by formula (3) is synthesized by reacting an aryl dihalide represented by formula (3a) (where Z represents a halogen atom such as I, Br, Cl, or F) with a primary aminoaryl represented by formula (3b).

[0241] [ka]

[0242] (In the above reaction equation, Ar 2 , R 3 ~R 6 k~m, p, and q are equivalent to those in equation (3) above.

[0243] In the polymerization method described above, the reaction that forms the N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, tert-butoxysodium, or triethylamine. It can also be carried out in the presence of a transition metal catalyst such as a copper or palladium complex.

[0244] [Second composition] The second composition forming the second organic layer will be described below. The second composition contains the second polymer and a solvent (organic solvent). This second composition is typically used to form the organic layer of the quantum dot light-emitting device of the present invention by a wet film deposition method. The organic layer is preferably a hole transport layer adjacent to the light-emitting layer formed by the light-emitting layer forming composition of the present invention. The second composition may contain one type of second polymer, or it may contain two or more types in any combination and ratio.

[0245] (Content of the second polymer) The content of the second polymer in the second composition is usually 0.01% by mass or more and 70% by mass or less, preferably 0.1% by mass or more and 60% by mass or less, and more preferably 0.5% by mass or more and 50% by mass or less. It is preferable that the content of the second polymer be within the above range because defects are less likely to occur in the formed organic layer and uneven film thickness is less likely to occur.

[0246] (solvent) The second composition typically contains a solvent. This solvent is preferably one that dissolves the second polymer. Specifically, a solvent that dissolves the second polymer in the second composition at a concentration of typically 0.05% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more, at room temperature is preferred.

[0247] Specific examples of solvents include aromatic solvents such as toluene, xylene, mesitylene, cyclohexylbenzene, and methylnaphthalene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene, and o-dichlorobenzene; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); and 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, and 3-methoxytoluene. Examples of organic solvents include ether-based solvents such as ene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole; aliphatic ester-based solvents such as ethyl acetate, n-butyl acetate, ethyl lactate, and n-butyl lactate; ester-based solvents such as aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, and n-butyl benzoate; and other organic solvents used in the hole injection layer formation compositions and hole transport layer formation compositions described later.

[0248] Furthermore, one type of solvent may be used, or two or more types may be used in any combination and ratio.

[0249] The surface tension of the solvent at 20°C is typically less than 40 dyn / cm, preferably 36 dyn / cm or less, and more preferably 33 dyn / cm or less.

[0250] On the other hand, the vapor pressure of the solvent at 25°C is usually 10 mmHg or less, preferably 5 mmHg or less, and usually 0.1 mmHg or more. By using such a solvent, a second composition suitable for the properties of the second polymer can be prepared, which is suitable for the process of manufacturing quantum dot light-emitting devices by wet film deposition.

[0251] Specific examples of such solvents include aromatic solvents such as toluene, xylene, mesitylene, and cyclohexylbenzene, as well as ether solvents and ester solvents.

[0252] Incidentally, moisture can cause performance degradation of quantum dot light-emitting devices, and in particular, it can accelerate the decrease in brightness during continuous operation. Therefore, in order to reduce residual moisture during wet film deposition as much as possible, the solubility of water in the solvent at 25°C is preferably 1% by mass or less, and more preferably 0.1% by mass or less.

[0253] The solvent content in the second composition is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 80% by mass or more. By having a solvent content above the lower limit mentioned above, the flatness and uniformity of the formed layer can be improved.

[0254] [Electron-accepting compounds] The second composition is preferably further enriched with an electron-accepting compound in terms of reducing resistance. In particular, when the second composition is used to form a hole injection layer, it is preferable that the second composition contains an electron-accepting compound.

[0255] As electron-accepting compounds, compounds that have oxidizing power and the ability to accept one electron from the second polymer contained in the second organic layer are preferred. Specifically, compounds with an electron affinity of 4 eV or more are preferred, and compounds with an electron affinity of 5 eV or more are more preferred.

[0256] The second composition may contain one of the above-mentioned electron-accepting compounds alone, or it may contain two or more in any combination and ratio.

[0257] If the second composition contains an electron-accepting compound, the content of the electron-accepting compound in the second composition is usually 0.0005% by mass or more, preferably 0.001% by mass or more, and usually 20% by mass or less, preferably 10% by mass or less.

[0258] Furthermore, the proportion of the electron-accepting compound to the second polymer in the second composition is usually 0.5% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and usually 80% by mass or less, preferably 60% by mass or less, and even more preferably 40% by mass or less.

[0259] It is preferable that the content of the electron-accepting compound in the second composition is above the lower limit, as this allows the electron acceptor to accept electrons from the second polymer, resulting in a lower resistance of the formed organic layer. It is also preferable that the content of the electron-accepting compound in the second composition is below the upper limit, as this makes it less likely for defects to occur in the formed organic layer and less likely for film thickness to be uneven.

[0260] [Cationic radical compounds] The second composition may further contain a cationic radical compound. As the cationic radical compound, an ionic compound consisting of a cationic radical, which is a chemical species obtained by removing one electron from a hole-transporting compound, and a counter anion is preferred. However, if the cationic radical is derived from a hole-transporting polymer compound, the cationic radical will have a structure obtained by removing one electron from the repeating unit of the polymer compound.

[0261] Furthermore, the cation radical is preferably a species obtained by removing one electron from a hole-transporting compound, as described later. It is preferable that the cation radical be a species obtained by removing one electron from a preferred hole-transporting compound, from the viewpoints of amorphousness, visible light transmittance, heat resistance, and solubility.

[0262] Here, a cationic radical compound can be generated by mixing a hole-transporting compound (described later) with the aforementioned electron-accepting compound. That is, by mixing the hole-transporting compound and the electron-accepting compound, electron transfer occurs from the hole-transporting compound to the electron-accepting compound, generating a cationic ion compound consisting of the cationic radical and counter anion of the hole-transporting compound.

[0263] If the second composition contains a cationic radical compound, the content of the cationic radical compound in the second composition is usually 0.0005% by mass or more, preferably 0.001% by mass or more, and usually 40% by mass or less, preferably 20% by mass or less. It is preferable that the content of the cationic radical compound is above the lower limit above because it reduces the resistance of the formed organic layer, and it is preferable that it is below the upper limit above because it reduces the likelihood of defects in the formed organic layer and reduces the likelihood of uneven film thickness.

[0264] In addition to the components described above, the second composition may also contain components included in the hole injection layer forming composition and the hole transport layer forming composition described later, in the amounts described later.

[0265] [Structure of quantum dot light-emitting element] As an example of the structure of the quantum dot light-emitting element of the present invention, Figure 1 shows a schematic diagram (cross-section) of an example of the structure of a quantum dot light-emitting element 8. In Figure 1, 1 represents the substrate, 2 the anode, 3 the hole injection layer, 4 the hole transport layer, 5 the light-emitting layer, 6 the electron transport layer, and 7 the cathode.

[0266] <Circuit board> The substrate 1 serves as a support for the quantum dot light-emitting element, and is typically made of quartz, glass, metal, metal foil, plastic film, or sheet. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, or polysulfone are preferred. The substrate is preferably made of a material with high gas barrier properties to prevent degradation of the quantum dot light-emitting element by the outside air. Therefore, 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 its gas barrier properties.

[0267] <Anode> Anode 2 is responsible for injecting holes into the layer on the light-emitting layer 5 side.

[0268] Anode 2 is typically composed 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 conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline.

[0269] The formation of anode 2 is usually carried out by dry methods such as sputtering or vacuum deposition. When forming the anode using metal nanoparticles such as silver, nanoparticles such as copper iodide, carbon black, conductive metal oxide nanoparticles, or conductive polymer fine powder, it can also be formed by dispersing them in a suitable binder resin solution and coating it onto a substrate. In the case of conductive polymers, the anode can also be formed by directly forming a thin film on the substrate by electrolytic polymerization, or by coating the substrate with conductive polymer (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0270] Anode 2 is usually a single-layer structure, but may be a multilayer structure as appropriate. If anode 2 is a multilayer structure, different conductive materials may be laminated on the first layer of anode.

[0271] The thickness of anode 2 can be determined according to the required transparency and material. When particularly high transparency is required, a thickness that allows for a visible light transmittance of 60% or more is preferable, and a thickness that allows for a visible light transmittance of 80% or more is even more preferable. The thickness of 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 anode 2 can be arbitrarily set according to the required strength, etc., and in this case, anode 2 may be the same thickness as the substrate.

[0272] When depositing other layers on the surface of anode 2, it is preferable to remove impurities from anode 2 and adjust its ionization potential to improve hole injection properties by treating it with ultraviolet / ozone, oxygen plasma, argon plasma, etc., before deposition.

[0273] <Hole injection layer> The layer responsible for transporting holes from the anode 2 to the light-emitting layer 5 is usually called a hole injection transport layer or hole transport layer. When there are two or more layers responsible for transporting holes from the anode 2 to the light-emitting layer 5, the layer closer to the anode is sometimes called the hole injection layer 3. It is preferable to form the hole injection layer 3 in order to enhance the function of transporting holes from the anode 2 to the light-emitting layer 5. When forming the hole injection layer 3, it is usually formed on the anode 2.

[0274] The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0275] The hole injection layer can be formed by either vacuum deposition or wet deposition. Wet deposition is preferable because it offers superior film formation properties.

[0276] The following describes a general method for forming a hole injection layer, but in the quantum dot light-emitting device of the present invention, it is preferable that the hole injection layer is formed by a wet deposition method using a hole injection layer forming composition.

[0277] (Hole transport compounds) A hole-injection layer-forming composition typically contains a hole-transporting compound that forms the hole-injection layer 3. In the case of a wet film deposition method, the hole-injection layer-forming composition also typically contains a solvent. It is preferable that the hole-injection layer-forming composition has high hole transport properties, allowing for efficient transport of injected holes. Therefore, it is preferable that the composition has high hole mobility and that trapping impurities are less likely to occur during manufacturing or use. Furthermore, it is preferable that the composition has excellent stability, a low ionization potential, and high transparency to visible light. In particular, when the hole-injection layer is in contact with the light-emitting layer, it is preferable that the composition does not quench the light emission from the light-emitting layer or form an excyplex with the light-emitting layer, thus not reducing the luminescence efficiency.

[0278] As hole-transporting compounds, compounds having an ionization potential of 4.5 eV to 6.0 eV are preferred from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of hole-transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which tertiary amines are linked by fluorene groups, hydrazone compounds, silazane compounds, quinacridone compounds, and the like.

[0279] Of the example compounds described above, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred, from the viewpoint of amorphousness and visible light transmittance. Here, aromatic tertiary amine compounds are compounds having an aromatic tertiary amine structure, and also include compounds having a group derived from an aromatic tertiary amine.

[0280] The type of aromatic tertiary amine compound is not particularly limited, but it is preferable to use a polymer compound (polymerized compound with repeating units) with a weight-average molecular weight of 1,000 or more and 1,000,000 or less, as it is easier to obtain uniform luminescence due to the surface smoothing effect.

[0281] (Formation of hole injection layer by wet deposition method) When forming a hole-injection layer 3 by a wet deposition method, a composition for film formation (hole-injection layer-forming composition) is typically prepared by mixing the material that will become the hole-injection layer with a soluble solvent (solvent for the hole-injection layer). Then, this hole-injection layer-forming composition is applied to the layer corresponding to the layer below the hole-injection layer (usually the anode), deposited, and dried to form the hole-injection layer 3.

[0282] The concentration of the hole transporting compound in the hole injection layer forming composition is arbitrary as long as it does not significantly impair the effects of the present invention. However, a lower concentration is preferable in terms of uniformity of film thickness, while a higher concentration is preferable in terms of preventing defects from forming in the hole injection layer. Specifically, it is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.5% by mass or more. On the other hand, it is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[0283] Examples of solvents include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

[0284] Examples of ether-based solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA), and aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole.

[0285] Examples of ester solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

[0286] Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene.

[0287] Examples of amide solvents include N,N-dimethylformamide and N,N-dimethylacetamide.

[0288] In addition to these, dimethyl sulfoxide and the like can also be used.

[0289] The hole injection layer 3 is typically formed by a wet deposition method, which involves preparing a hole injection layer formation composition, coating it onto the layer below the hole injection layer 3 (usually the anode 2), and then drying it. The hole injection layer 3 is typically dried after film formation by heating or reduced-pressure drying.

[0290] (Formation of a hole injection layer by vacuum deposition) When forming the hole injection layer 3 by vacuum deposition, typically one or more of the constituent materials for the hole injection layer 3 are placed in a crucible installed inside a vacuum chamber (if more than two materials are used, each is usually placed in a separate crucible), and the inside of the vacuum chamber is vacuumed with a vacuum pump for 10°C. -4 The system is evacuated to approximately Pa. Then, the crucible is heated (if two or more materials are used, each crucible is usually heated separately) to evaporate the materials in the crucible while controlling the evaporation rate (if two or more materials are used, each is usually evaporated independently) to form a hole injection layer on the anode on the substrate placed facing the crucible. Alternatively, if two or more materials are used, a mixture of these materials can be placed in the crucible, heated, and evaporated to form the hole injection layer.

[0291] The vacuum level during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is typically 0.1 × 10⁻⁶. -6 Torr(0.13×10 -4 Pa) or more, 9.0×10 -6 Torr(12.0×10 -4 The pressure is less than or equal to Pa. 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 deposition temperature during deposition is not limited as long as it does not significantly impair the effects of the present invention, but is preferably 10°C or more and 50°C or less.

[0292] The hole injection layer 3 may also be crosslinked.

[0293] <Hole transport layer> The hole transport layer 4 is a layer responsible for transporting holes from the anode 2 to the light-emitting layer 5. In the quantum dot light-emitting device of the present invention, it is preferable to form the hole transport layer 4 because it enhances the function of transporting holes from the anode 2 to the light-emitting layer 5. When the hole transport layer 4 is formed, it is usually formed between the anode 2 and the light-emitting layer 5. Also, 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.

[0294] The thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, while it is usually 300 nm or less, preferably 100 nm or less.

[0295] The hole transport layer 4 may be formed by vacuum deposition or wet deposition. Wet deposition is preferable because it offers superior film formation properties.

[0296] A general method for forming a hole transport layer is described below, but in the quantum dot light-emitting device of the present invention, it is preferable that the hole transport layer is formed by a wet deposition method using the second composition described above as the composition for forming the hole transport layer.

[0297] The hole transport layer 4 typically contains a hole-transporting compound. The second polymer contained in the second organic layer is preferred as the hole-transporting compound in the hole transport layer 4.

[0298] In addition to the second polymer, the hole transport layer 4 contains the aforementioned hole transport compound, an aromatic diamine represented by 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, in which two or more tertiary amines are contained and two or more condensed aromatic rings are substituted with nitrogen atoms (Japanese Patent Publication No. 5-234681), an aromatic amine compound having a starburst structure such as 4,4',4”-tris(1-naphthylphenylamino)triphenylamine (J. Lumin., Vol. 72-74, p. 985, 1997), and an aromatic amine compound consisting of a tetramer of triphenylamine (Chem. Commun., 21 Preferred examples include spiro compounds such as 2,2',7,7'-tetrakis-(diphenylamino)-9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), carbazole derivatives such as 4,4'-N,N'-dicarbazolebiphenyl. Furthermore, for example, polyvinylcarbazole, polyvinyltriphenylamine (Japanese Patent Publication No. 7-53953), and polyarylene ethersulfone containing tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, p. 33, 1996) may also be included.

[0299] (Formation of hole transport layer by wet film deposition method) When forming a hole transport layer using a wet deposition method, the hole transport layer is usually formed using a hole transport layer formation composition instead of a hole injection layer formation composition, in the same manner as when forming the hole injection layer using the wet deposition method described above.

[0300] When forming a hole transport layer by a wet film deposition method, the hole transport layer forming composition typically also contains a solvent. The solvent used in the hole transport layer forming composition can be the same solvent used in the hole injection layer forming composition described above.

[0301] The concentration of the hole-transporting compound in the hole-transporting layer-forming composition can be within the same range as the concentration of the hole-transporting compound in the hole-injection layer-forming composition.

[0302] The hole transport layer can be formed by a wet deposition method in the same manner as the hole injection layer deposition method described above.

[0303] (Formation of a hole transport layer by vacuum deposition) When forming a hole transport layer by vacuum deposition, it is usually possible to form it using a hole transport layer formation composition instead of a hole injection layer formation composition, in the same manner as when forming the hole injection layer by vacuum deposition described above. The deposition conditions, such as the degree of vacuum, deposition rate, and temperature, can be the same as those for vacuum deposition of the hole injection layer.

[0304] <Luminous layer> The light-emitting layer 5 is a layer that is excited and emits light when an electric field is applied between a pair of electrodes, by the recombination of holes injected from the anode 2 and electrons injected from the cathode 7. The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 7. If there is a hole injection layer above the anode, the light-emitting layer is formed between the hole injection layer and the cathode. If there is a hole transport layer above the anode, the light-emitting layer is formed between the hole transport layer and the cathode. In the quantum dot light-emitting device of the present invention, it is preferable that the light-emitting layer is the light-emitting layer in the first embodiment or the light-emitting layer in the second embodiment.

[0305] The thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention. However, a thicker film is preferable in that defects are less likely to occur in the film, while a thinner film is preferable in that it is easier to achieve a low driving voltage. For this reason, the thickness of the light-emitting layer 5 is preferably 2 nm or more, more preferably 5 nm or more, while usually preferably 200 nm or less, and more preferably 100 nm or less.

[0306] 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. The host material is usually a charge transport material, but a material with low charge transport properties may be added to adjust the charge transport properties.

[0307] (Formation of the light-emitting layer by wet film deposition method) The method for forming the light-emitting layer may be vacuum deposition or wet deposition, but wet deposition is preferred due to its superior film-forming properties, and spin coating and inkjet methods are even more preferred. In particular, when a hole injection layer or hole transport layer, which is the layer below the light-emitting layer, is formed using the light-emitting layer forming composition of the present invention, it is preferable to use wet deposition because lamination by wet deposition is easy. When forming the light-emitting layer by wet deposition, it is usually done in the same way as when forming the hole injection layer by wet deposition, using a light-emitting layer forming composition prepared by mixing the material to be the light-emitting layer with a soluble solvent (light-emitting layer solvent) instead of the hole injection layer forming composition.

[0308] Examples of solvents include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents, as mentioned for the formation of the hole implantation layer, as well as alkane-based solvents, halogenated aromatic hydrocarbon-based solvents, aliphatic alcohol-based solvents, alicyclic alcohol-based solvents, aliphatic ketone-based solvents, and alicyclic ketone-based solvents. Specific examples of solvents are given below, but the invention is not limited to these, as long as they do not impair the effects of the present invention.

[0309] For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ether solvents such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenethole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, and diphenyl ether; aromatic ester solvents such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1, Examples include aromatic hydrocarbon solvents such as 2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene; amide solvents such as N,N-dimethylformamide and N,N-dimethylacetamide; alkane solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, and bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene, and trichlorobenzene; aliphatic alcohol solvents such as butanol and hexanol; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; and alicyclic ketone solvents such as cyclohexanone, cyclooctanone, and fencone. Of these, alkane solvents and aromatic hydrocarbon solvents are particularly preferred.

[0310] <Hole Blocking Layer> A hole-blocking layer may be provided between the light-emitting layer 5 and the electron transport layer 6, which will be described later. The hole-blocking layer is a layer laminated on top of 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.

[0311] This hole-blocking layer has two roles: preventing holes moving from anode 2 from reaching cathode 7, and efficiently transporting electrons injected from cathode 7 towards the light-emitting layer 5. The required properties for the material constituting the hole-blocking layer include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and a high excited triplet level (T1).

[0312] Examples of hole blocking layer materials that satisfy these conditions include mixed ligand complexes such as bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato)(triphenylsilanolato)aluminum, metal complexes such as bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolinolato)aluminum dinuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Publication No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Publication No. 7-41759), and phenanthroline derivatives such as basocproine (Japanese Patent Publication No. 10-79297). Furthermore, compounds having at least one pyridine ring substituted at the 2,4, and 6 positions, as described in International Publication No. 2005 / 022962, are also preferred as materials for hole blocking layers.

[0313] There are no restrictions on the method of forming the hole blocking layer. Therefore, it can be formed by wet deposition, vapor deposition, or other methods.

[0314] The thickness of the hole blocking layer is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.3 nm or more, preferably 0.5 nm or more, and is usually 100 nm or less, preferably 50 nm or less.

[0315] <Electron transport layer> The electron transport layer 6 is provided between the light-emitting layer 5 and the cathode 7 with the aim of further improving the current efficiency of the device.

[0316] The electron transport layer 6 is formed from a compound that can efficiently transport electrons injected from the cathode 7 towards the light-emitting layer 5 between electrodes under an applied electric field. The electron transport compound used in the electron transport layer 6 must have high electron injection efficiency from the cathode 7, high electron mobility, and be able to efficiently transport the injected electrons.

[0317] Examples of electron-transporting compounds used in the electron transport layer include, for example, metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Publication No. 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Patent Publication No. 6-207169), phenanthroline derivatives (Japanese Patent Publication No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, and the like.

[0318] 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.

[0319] The electron transport layer 6 is formed by laminating it onto the light-emitting layer or hole-blocking layer using a wet deposition method or vacuum deposition method, as described above. Vacuum deposition is usually used.

[0320] <Electron injection layer> To efficiently inject electrons injected from the cathode 7 into the electron transport layer 6 or the light-emitting layer 5, an electron injection layer may be provided between the electron transport layer 6 and the cathode 7.

[0321] To efficiently perform electron injection, 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, and alkaline earth metals such as barium and calcium. The film thickness is usually preferably between 0.1 nm and 5 nm.

[0322] Furthermore, doping organic electron transport materials, such as nitrogen-containing heterocyclic compounds like bathophenanthroline and metal complexes like aluminum complexes of 8-hydroxyquinoline, with alkali metals such as sodium, potassium, cesium, lithium, and rubidium (as described in Japanese Patent Publication No. 10-270171, Japanese Patent Publication No. 2002-100478, Japanese Patent Publication No. 2002-100482, etc.) is also preferable because it improves electron injection and transport properties and enables the achievement of excellent film quality.

[0323] The thickness of the electron injection layer is typically 5 nm or more, preferably 10 nm or more, and typically 200 nm or less, preferably 100 nm or less.

[0324] The electron injection layer is formed by laminating it onto the light-emitting layer 5 or the hole-blocking layer or electron transport layer 6 located thereon, using a wet deposition method or a vacuum deposition method. The details for the wet film deposition method are the same as those for the luminescent layer described above.

[0325] In some cases, the hole blocking layer, electron transport layer, and electron injection layer are combined into a single layer by co-doping the electron transport material with a lithium complex.

[0326] <Cathode> The cathode 7 plays the role of injecting electrons into the layer on the light-emitting layer 5 side (such as the electron injection layer or light-emitting layer).

[0327] As the material for the cathode 7, the same material used for the anode 2 can be used. However, for efficient electron injection, it is preferable to use a metal with a low work function. For example, metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys thereof, can be used. Specific examples include low-work-function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

[0328] In terms of the stability of quantum dot light-emitting devices, it is preferable to protect the cathode, which is made of a metal with a low work function, by laminating a metal layer with a high work function and stability to the atmosphere on top of the cathode. Examples of metals that can be laminated include aluminum, silver, copper, nickel, chromium, gold, and platinum.

[0329] The film thickness of the cathode is usually the same as that of the anode.

[0330] <Other layers> The quantum dot light-emitting element of the present invention may have other layers, provided that they do not significantly impair the effects of the present invention. That is, any other layer described above may be present between the anode and the cathode.

[0331] <Other component configurations> The quantum dot light-emitting device of the present invention can also have a structure reversed from the above description, that is, for example, stacking cathode, electron injection layer, electron transport layer, hole blocking layer, light-emitting layer, hole transport layer, hole injection layer, and anode on a substrate in that order.

[0332] When applying the quantum dot light-emitting element of the present invention to an organic electroluminescent device, it may be used as a single quantum dot light-emitting element, as a configuration in which multiple quantum dot light-emitting elements are arranged in an array, or as a configuration in which the anode and cathode are arranged in an XY matrix.

[0333] [Quantum dot display device] The quantum dot display device (quantum dot light-emitting device display device) of the present invention comprises the quantum dot light-emitting element of the present invention. There are no particular restrictions on the type or structure of the quantum dot display device of the present invention, and it can be assembled according to conventional methods using the quantum dot light-emitting element of the present invention.

[0334] For example, the quantum dot display device of the present invention can be formed by replacing the organic light-emitting layer with a light-emitting layer containing quantum dots, referring to a method such as the one described in "Organic EL Display" (Ohmsha, published August 20, 2004, authored by Shizuka Tokito, Chihaya Adachi, and Hideyuki Murata).

[0335] [Quantum dot lighting] The quantum dot illumination (quantum dot light-emitting element illumination) of the present invention comprises the quantum dot light-emitting element of the present invention. There are no particular restrictions on the type or structure of the quantum dot illumination of the present invention, and it can be assembled according to conventional methods using the quantum dot light-emitting element of the present invention. [Examples]

[0336] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples, and can be modified and implemented as such without departing from its essence.

[0337] [Example 1] Quantum dot light-emitting devices were fabricated using the following method. A transparent conductive film of indium tin oxide (ITO) was deposited to a thickness of 50 nm on a glass substrate (Geomatec Co., Ltd., sputter-deposited product). This film was then patterned into 2 mm wide stripes using conventional photolithography techniques and hydrochloric acid etching to form an anode. The substrate with the ITO pattern was then cleaned in the following order: ultrasonic cleaning with a surfactant aqueous solution, rinsing with ultrapure water, ultrasonic cleaning with ultrapure water, and rinsing with ultrapure water. After drying with compressed air, the substrate was finally cleaned with ultraviolet ozone.

[0338] As a composition for forming a hole injection layer, a composition was prepared by dissolving 3.0% by mass of a hole-transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by mass of an electron-accepting compound (HI-1) in ethyl benzoate.

[0339] [ka]

[0340] This hole injection layer formation composition was spin-coated onto the substrate in air, dried on a hot plate at 240°C for 30 minutes in air to form a uniform thin film with a thickness of 40 nm, which served as the hole injection layer.

[0341] Next, a charge-transporting polymer compound having the following structural formula (HT-1) was dissolved in 1,3,5-trimethylbenzene at a concentration of 2.0% by mass to prepare a hole transport layer forming composition.

[0342] [ka]

[0343] This hole transport layer-forming composition was spin-coated onto a substrate coated with the hole injection layer 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, which served as the hole transport layer.

[0344] Subsequently, a toluene solution containing 1.35% by mass of CdZnSeS nanoparticles and 0.15% by mass of a compound having the structure represented by the following formula (H-1) was prepared as a composition for forming the light-emitting layer. This was then spin-coated onto a substrate coated with the hole transport layer at 3000 revolutions per minute for 30 seconds in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 100°C for 10 minutes to form the light-emitting layer.

[0345] [ka]

[0346] A substrate with the light-emitting layer deposited is placed in a vacuum deposition apparatus, and the inside of the apparatus is 2 × 10 -4 The exhaust was vented until the pressure dropped below Pa.

[0347] Next, the following structural formula (ET-1) and 8-hydroxyquinolinolatritium were co-deposited onto the light-emitting layer in a film thickness ratio of 2:3 using vacuum deposition to form an electron transport layer with a thickness of 45 nm.

[0348] [ka]

[0349] Next, a 2mm wide striped shadow mask was placed in close contact with the substrate as a mask for cathode deposition, perpendicular to the ITO stripe of the anode. The aluminum was then heated using a molybdenum boat to form an aluminum layer with a thickness of 80nm, thereby forming the cathode. In this way, a quantum dot light-emitting element with a light-emitting area of ​​2 mm x 2 mm was obtained.

[0350] [Comparative Example 1] A quantum dot light-emitting device was fabricated in the same manner as in Example 1, except that a light-emitting layer was formed using a toluene solution with a composition containing 1.5% by mass of CdZnSeS nanoparticles and no compounds having the structure represented by the formula (H-1).

[0351] [Evaluation of the element] When the quantum dot light-emitting devices obtained in Example 1 and Comparative Example 1 were activated, red light emission with a peak wavelength of 628 nm and a full width at half maximum of 27 nm was obtained. A current of 10 mA / cm² was applied to the device. 2 The brightness half-life (LT50) was measured when power was continuously supplied at the specified current density. Table 1 shows the relative brightness half-life (LT50) of the quantum dot light-emitting element of Example 1, with the brightness half-life (LT50) of the quantum dot light-emitting element of Comparative Example 1 set to 1. In Table 1, CdZnSeS nanoparticles are denoted as "QD," and compounds having the structure represented by formula (H-1) are denoted as "H-1."

[0352] [Table 1]

[0353] The results in Table 1 show that the quantum dot light-emitting device of the present invention exhibits improved performance. [Industrial applicability]

[0354] The present invention can be suitably used in various fields in which quantum dot light-emitting elements are used, such as flat panel displays (e.g., for office computers and wall-mounted televisions), light sources that take advantage of their surface-emitting properties (e.g., light sources for photocopiers, liquid crystal displays and backlights for instruments), display boards, and indicator lights. [Explanation of symbols]

[0355] 1 circuit board 2 Anode 3. Hole injection layer 4. Hole transport layer 5. Emitting layer 6 Electron transport layer 7 Cathode 8 Quantum dot light-emitting devices

Claims

1. The material comprises a quantum dot, a compound represented by the following formula (1), other charge transport materials other than the compound represented by the following formula (1), and an organic solvent. A composition for forming a light-emitting layer of a quantum dot light-emitting device, wherein the total content of the compound represented by formula (1) and the other charge transport materials is 0.01 parts by mass or more and 1 part by mass or less per 1 part by mass of quantum dot. 【Chemistry 1】 (In formula (1), Ar ２１ Ar ２２ Each of these is independently a benzene ring which may have substituents or a naphthalene ring which may have substituents, and the substituents which may be aromatic hydrocarbon groups having 6 to 24 carbon atoms, or alkyl groups having 1 to 6 carbon atoms. e, g, f, and h are all 0.

2. A composition for forming the light-emitting layer of a quantum dot light-emitting device, comprising a quantum dot, a compound represented by the following formula (1A), and an organic solvent. 【Chemistry 2】 (In formula (1A), Ar ２１ Ar ２２ Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. R ２１ ~R ２４ Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted alkyl groups, optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. e and g are independent integers between 0 and 4. f and h are independent integers between 0 and 3.

3. A method for manufacturing a quantum dot light-emitting element, comprising the step of applying and drying the composition for forming the light-emitting layer of the quantum dot light-emitting element according to claim 1 or 2 to form a light-emitting layer.

4. A method for manufacturing a quantum dot display device, comprising the method for manufacturing a quantum dot light-emitting element according to claim 3.

5. A method for manufacturing quantum dot illumination, comprising the method for manufacturing a quantum dot light-emitting element according to claim 3.

6. It has an anode, a cathode, and a light-emitting layer provided between the anode and the cathode, The light-emitting layer comprises quantum dots, a compound represented by the following formula (1), and other charge transport materials other than the compound represented by the following formula (1). A quantum dot light-emitting element, wherein the total content of the compound represented by formula (1) and the other charge transport material is 0.01 parts by mass or more and 1 part by mass or less per 1 part by mass of quantum dot. 【Transformation 3】 (In formula (1), Ar ２１ Ar ２２ Each of these is independently a benzene ring which may have substituents or a naphthalene ring which may have substituents, and the substituents which may be aromatic hydrocarbon groups having 6 to 24 carbon atoms, or alkyl groups having 1 to 6 carbon atoms. e, g, f, and h are all 0.

7. It has an anode, a cathode, and a light-emitting layer provided between the anode and the cathode, A quantum dot light-emitting element, wherein the light-emitting layer comprises quantum dots and a compound represented by the following formula (1A). 【Chemistry 4】 (In formula (1A), Ar ２１ and Ar ２２ each independently represent a monovalent group in which 2 to 7 structures selected from an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent and an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent are linked, R ２１ ~R ２４ Each of these independently represents a monovalent group consisting of 2 to 7 structures selected from optionally substituted alkyl groups, optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms, optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms, or optionally substituted aromatic hydrocarbon groups having 6 to 30 carbon atoms and optionally substituted aromatic heterocyclic groups having 3 to 30 carbon atoms. e and g are independent integers between 0 and 4. f and h are independent integers between 0 and 3.

8. A quantum dot display device comprising a quantum dot light-emitting element according to claim 6 or 7.

9. A quantum dot illumination comprising a quantum dot light-emitting element according to claim 6 or 7.

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