JP2021039940A - Quantum dot, ink composition, electroluminescent element, and photoelectric conversion element - Google Patents

Abstract

To provide a quantum dot and an ink composition having excellent stability over time, and capable of maintaining a high fluorescence quantum yield even after aging.SOLUTION: A quantum dot is a semiconductor fine particle surface-treated with a ligand compound having an aliphatic heterocyclic site containing a sulfur atom represented by the general formula (1) and a charge transporting site. [In the general formula (1), Q is an aliphatic heterocyclic group containing a sulfur atom, X is a direct bond or a divalent linking group, and A is a charge transporting group].SELECTED DRAWING: None

Description

The present invention relates to quantum dots, which are semiconductor fine particles surface-treated with a compound having an aliphatic heterocyclic group containing a sulfur atom and a charge transporting group, an ink composition containing the quantum dots, an electroluminescent element, and a photoelectric conversion element. Regarding.

Quantum dots are tiny particles (dots) formed to confine electrons in a minute space in order to express unique optical properties that follow quantum mechanics. The size of one quantum dot is from 1 nm to several tens of nm in diameter, and is composed of about 10,000 or less atoms. Quantum dots have been attracting attention in recent years because the wavelength of fluorescence emitted can be continuously controlled by the size of the grain and the wavelength distribution of fluorescence intensity can provide sharp light emission with high symmetry. Since fluorescence can be adjusted to a wavelength that is easy to use and can be delivered to anywhere in the body, it can be used for bioimaging as a light emitting material, for solar cells as a wavelength conversion material that does not have a risk of fading, and for electronics as a clear light emitting material or wavelength conversion material. -Study is underway for photonics applications.

On the other hand, the quantum yield of fluorescence can be mentioned as a characteristic required for development in the above applications. Non-Patent Document 1 describes that the fluorescence quantum yield is improved by using quantum dots in which semiconductor fine particles are coated with benzenethiol, which is an aromatic thiol.

Nanotechnology 27 (24): 245203

However, in the quantum dots coated with benzenethiol described in Non-Patent Document 1, the benzenethiol itself, which is a coating material, is relatively easily oxidized, and there is a problem in stability over time. As a result, the composition in which the quantum dots are mixed with a solvent or a binder component has insufficient stability over time, and there is a problem that aggregation and precipitation of the quantum dots occur. In addition, there is a problem that the quantum yield maintenance rate of fluorescence is significantly reduced.
Therefore, an object of the present invention is to provide a quantum dot and an ink composition which are excellent in stability with time and can maintain a high fluorescence quantum yield even after a lapse of time. Another object of the present invention is to provide a highly reliable electroluminescent device using quantum dots capable of maintaining a high fluorescence quantum yield even after a lapse of time.

Another object of the present invention is to provide a photoelectric conversion element having excellent durability.

The present invention relates to the following inventions.
[1] Quantum dots, which are semiconductor fine particles surface-treated with a compound represented by the following general formula (1).

［一般式（１）中、Ｑは硫黄原子を含有する脂肪族複素環基であり、Ｘは直接結合又は２
価の連結基であり、Ａは電荷輸送性基である。］ General formula (1)

[In the general formula (1), Q is an aliphatic heterocyclic group containing a sulfur atom, and X is a direct bond or 2
It is a valence linking group and A is a charge transporting group. ]

[2] The quantum dot according to [1], wherein the semiconductor fine particles are compound semiconductors.

[3] The quantum dot according to [1] or [2], wherein the semiconductor fine particles are of a core-shell type.

[4] The quantum dot according to any one of [1] to [3], wherein the charge transporting group is a hole transporting group.

[5] An ink composition containing the quantum dots according to any one of [1] to [4] and a solvent.

[6] The ink composition according to [5], which is used in an inkjet method.

[7] An electroluminescent device comprising an anode, a light emitting layer, and a cathode on a substrate, wherein the light emitting layer contains the quantum dots according to any one of [1] to [5].

[8] A photoelectric conversion element having a photoelectric conversion layer between a pair of electrodes, wherein the photoelectric conversion layer contains the quantum dots according to any one of [1] to [5]. element.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a quantum dot and an ink composition which are excellent in stability with time and can maintain a high fluorescence quantum yield even after a lapse of time. Further, according to the present invention, it is possible to provide a highly reliable electroluminescent device using quantum dots capable of maintaining a high fluorescence quantum yield even after a lapse of time.

Further, according to the present invention, it is possible to provide a photoelectric conversion element having excellent durability.

<Quantum dot>
The quantum dots of the present invention are semiconductor fine particles surface-treated with the compound represented by the general formula (1). "Surface-treated" means that the compound is contained in at least a part of the surface of the semiconductor fine particles, and the compound present on the surface of such semiconductor fine particles is also referred to as a ligand. The compound represented by the general formula (1) has an aliphatic heterocyclic group containing a sulfur atom and a charge transporting group. The aliphatic heterocyclic group containing a sulfur atom has high oxidation resistance and can stably exist on the surface of quantum dots even with time. As a result, the quantum dots of the present invention exhibit excellent stability over time in addition to charge transportability. As a result, as compared with the conventional quantum dots coated with benzenethiol or the like, precipitation does not occur, the stability over time is excellent, and the fluorescence quantum yield retention rate is high, which is suitable as a light emitting material.
Hereinafter, the present invention will be described in detail. Unless otherwise specified, "parts" and "%" represent "parts by mass" and "% by mass".

<Semiconductor fine particles>
As the material of the semiconductor fine particles, a single element of Group IV of the periodic table such as carbon (C) (atypical carbon, graphite, graphene, carbon nanotubes, etc.), silicon (Si), germanium (Ge), tin (Sn); Single elements of Group V of the Periodic Table such as phosphorus (P) (black phosphorus); Single elements of Group VI of the Periodic Table such as selenium (Se) and Tellur (Te); Tin (IV) oxide, Boron (BN) nitride , Boron phosphide (BP), borron arsenide (BAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonized (AlSb), gallium nitride (GaN), gallium phosphide With Group III elements of the Periodic Table such as GaP), gallium arsenide (GaAs), gallium antimonized (GaSb), indium nitride (InN), indium phosphate (InP), indium arsenide (InAs), and indium antimonized (InSb). Compounds with Group V Elements of the Periodic Table; Aluminum _{Sulfate (Al 2} S ₃ ), Aluminum _{Serene (Al 2} Se ₃ ), Gallium Sulfide (Ga ₂ S ₃ ), Gallium Selenium (Ga Se _{, Ga 2 Se 3} ) Telluru Gallium oxide (Ga Te, Ga _{2 Te 3} ), indium oxide (In ₂ O ₃ ), indium sulfide (In ₂ S ₃ , In S), indium selenium (In ₂ Se ₃ ), indium telluride (In ₂ Te ₃ ) Compounds of Group III elements of the Periodic Table and Group VI of the Periodic Table; zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenium (ZnSe), zinc tellurate (ZnTe), cadmium oxide (CdO) , Periodic Table Group II elements and periodic table of cadmium sulfide (CdS), cadmium selenium (CdSe), cadmium telluride (CdTe), mercury sulfide (HgS), mercury selenium (HgSe), mercury telluride (HgTe), etc. Compounds with Group VI Elements in Table; Copper (I) (Cu ₂ O), Copper (I) (Cu ₂ S), Copper (I) Serene (Cu ₂ Se), Silver (I) (Ag) ₂ S), silver selenium (I) (Ag ₂ Se), silver telluride (I) (Ag ₂ Te), gold sulfide (I) (Au ₂ S), gold selenium (I) (Au ₂ Se) , Compounds of Group I elements of the Periodic Table and Group VI of the Periodic Table such as tellurized gold (I) (Au ₂ Te); copper (I) chloride (CuCl), copper (I) bromide (CuBr), Copper iodide (I) (CuI), silver chloride (AgC) l), Compounds of Group I elements of the Periodic Table and Group VII elements of the Periodic Table such as silver bromide (AgBr); tin sulfide (II) (SnS), tin selenium (II) (SnSe), tin telluride Periodic Table Group IV and Periodic Table Group VI elements such as (II) (SnTe), lead sulfide (II) (PbS), lead selenium (II) (PbSe), lead telluride (II) (PbTe) Compounds with Group V elements of the Periodic Table and Group VI elements of the Periodic Table, such as Antimon Sulfurized (III) (Sb ₂ S ₃ ) and Bismus Sulfurized (III) (Bi ₂ S _{3); 2} ), Compounds of Group VIII elements of the Periodic Table and Group VI of the Periodic Table, such as iron selenium (FeSe ₂ ) and iron tellurate (FeTe _2); Examples include compounds of a lanthanoid element such as europium tellurized (EuTe) and a Group VI element of the periodic table, and two or more of these may be used in combination if necessary. These semiconductors may contain elements other than the constituent elements. For example, taking Group III-V as an example, it may be an alloy system such as InGaP or InGaN, or it may be an alloy system such as _{CuInS 2} , CuInSe ₂ or CuInTe _{2 containing elements of a plurality of groups.} .. Further, semiconductor fine particles doped with a rare earth element or a transition metal element can be used in the above materials, and examples thereof include ZnS: Mn, ZnS: Tb, ZnS: Ce, and LaPO ₄ : Ce.

Further, as the material of the semiconductor fine particles, perovskite crystals can also be preferably used. The perovskite crystal has a composition represented by the following formula (I) and has a three-dimensional crystal structure.
Equation (I): AQX ₃
[In formula (I), A is [CH ₃ NH ₃ ] ⁺ , [NH ₃ CHNH] ⁺ , Rb ⁺ , Cs ⁺ or Fr ⁺ , Q is Pb ²⁺ or Sn ²⁺ , and X. it ^{is, I -, Br -, Cl} - or F ^- a. ]

Semiconductor fine particles used in the electric field light emitting element include silicon (Si), germanium (Ge), gallium nitride (GaN), gallium cadmium (GaP), gallium arsenide (GaAs), indium nitride (InN), and indium phosphate (InN). InP), indium arsenide (InAs), gallium selenide (GaSe, Ga ₂ Se ₃ ), indium sulfide (In ₂ S ₃ , InS), zinc oxide (ZnO), zinc sulfide (ZnS), zinc cadmium (ZnSe) , Zinc telluride (ZnTe), cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium selenide (CdTe), InGaP, InGaN and other alloys are preferably used. Indium (InP), cadmium selenide (CdSe), zinc sulfide (ZnS), and zinc selenide (ZnSe) are particularly preferably used. In particular, it is preferable to use InP as the core and ZnS and / or ZnSe as the shell.

It is preferable that the semiconductor fine particles used in the photoelectric conversion element can absorb electromagnetic waves having a wavelength of 700 to 2500 nm. Examples include compound semiconductors and metal chalcogenides having a perovskite crystal structure (eg, oxides, sulfides, seleniums, tellurides, etc.). Specific examples of the compound semiconductor having a perovskite crystal structure include CH ₃ NH ₃ PbF ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI ₃ , CsPbF ₃ , CsPbCl ₃ , and CsPbBr. ₃ , CsPbI ₃ , RbPbF ₃ , RbPbCl ₃ , RbPbBr ₃ , RbPbI ₃ , KPbF ₃ , KPbCl ₃ , KPbBr ₃ , KPbI _{3 and the} like. Specific examples of the metal chalcogenide include PbS, PbSe, PbTe, CdS, CdSe, CdTe, Sb ₂ S ₃ , Bi ₂ S ₃ , Ag ₂ S, Ag ₂ Se, Ag ₂ Te, Au ₂ S, and so on. Au ₂ Se, Au ₂ Te, Cu ₂ S, Cu ₂ Se, Cu ₂ Te, Fe ₂ S, Fe ₂ Se, Fe ₂ Te, In ₂ S3, SnS, SnSe, SnTe, CuInS ₂ , CuInSe ₂ , CuInTe ₂ , EuS, EuSe, EuTe and the like. Among these, PbS, PbSe, Ag ₂ S is preferred.

The semiconductor fine particles used in the electroluminescent device are preferably core-shell type semiconductor fine particles having a core-shell structure. The core-shell type semiconductor fine particles have a structure having a core and a shell in which the core is coated with a material different from the material forming the core. By selecting a semiconductor with a large bunt gap for the shell, excitons (electron-hole pairs) generated by photoexcitation are confined in the core. As a result, the probability of non-radiative transition on the particle surface is reduced, and the quantum yield of emission and the stability of fluorescence characteristics are improved. Further, the shell may have a plurality of layers. Further, the boundary between the core and the shell, and one shell and the other shell may be clear or may be a gradient structure in which the core and the shell are gradually joined with a concentration gradient. Further, the shell may cover only a part of the core or the whole core.

The average particle size of the semiconductor fine particles including the core and the shell is usually 0.5 nm to 100 nm, preferably 1 to 50 nm, and more preferably 1 to 15 nm.

Here, the average particle size refers to a value obtained by observing semiconductor fine particles with a transmission electron microscope, randomly measuring 30 sizes, and adopting the average value. At this time, the semiconductor fine particles are accompanied by an organic ligand described later. On the other hand, by using a scanning transmission electron microscope accompanied by energy dispersive X-ray analysis, semiconductor fine particles excluding organic ligands are specified and the particle size is measured. The identification of the semiconductor fine particles utilizes the fact that the semiconductor fine particles are imaged darker than the organic ligand in the transmission electron microscope image due to the difference in electron density. The shape of the semiconductor fine particles is not limited to a spherical shape, and may be a rod shape, a disk shape, or any other shape.

<Ligand: Compound represented by general formula (1)>
The compound represented by the general formula (1) covers at least a part of the surface of the semiconductor fine particles and is used for the surface treatment of the semiconductor fine particles.

［一般式（１）中、Ｑは硫黄原子を含有する脂肪族複素環基であり、Ｘは直接結合又は２価の連結基であり、Ａは電荷輸送性基である。］ General formula (1)

[In the general formula (1), Q is an aliphatic heterocyclic group containing a sulfur atom, X is a direct bond or a divalent linking group, and A is a charge transporting group. ]

The aliphatic heterocyclic group containing a sulfur atom is an aliphatic heterocycle containing at least one sulfur atom as a ring-constituting heteroatom, for example, an aliphatic heterocyclic group containing a sulfur atom and having 2 to 30 carbon atoms. Specifically, examples of the aliphatic heterocyclic group containing a sulfur atom include an ethylene sulfide ring, a trimethylene sulfide ring, a tetrahydrothiophene ring, a dithiane ring, a thiepan ring, a thiocan ring, and a thionan ring. Examples thereof include a thiazolidine ring, a 1,2-dithiane ring, a 1,3-dithiane ring, a 1,4-dithiane ring, a thiomorpholin ring and the like.

The aliphatic heterocyclic group may contain a hetero atom other than the sulfur atom in the ring structure, or may contain a sulfur atom and at least one atom selected from a nitrogen atom and an oxygen atom as the ring structure hetero atom. The aliphatic heterocyclic group more preferably contains a sulfur atom and a nitrogen atom as a ring-constituting heteroatom.
Further, as the number of ring members of the aliphatic heterocyclic group, a 3- to 8-membered ring is preferable, and a 5-membered ring or a 6-membered ring is more preferable.

The divalent linking group consists of a divalent hydrocarbon group, an oxygen atom, an amide group, a carbonyl group, an ester group, an imide group, an azomethine group, an azo group, a sulfide group, a sulfone group, or a combination thereof. A valuation linking group can be mentioned.

Examples of the divalent hydrocarbon group include an alkylene group, a cycloalkylene group, an arylene group and the like, among which an alkylene group having 1 to 12 carbon atoms, a cycloalkylene group having 5 to 12 carbon atoms and a carbon number of carbon atoms are used. 6-12 arylene groups are preferred. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a hexylene group, a dodecylene group, a cyclohexylene group, a phenylene group and the like. As X, it is preferably a direct bond.

The charge transporting group includes a hole transporting group and an electron transporting group. Since the hole-transporting group is mainly responsible for the transport of holes, stability for holes, that is, oxidative stability is required, while the electron-transporting group is responsible for the transport of electrons, so that it is stable for electrons, that is, reduction stability. Sex is required.
As the hole transporting group, for example, a group containing a unit such as a tertiary aromatic amine such as triphenylamine or diphenylamine, carbazole, or thiophene can be used.
As the electron-transporting group, for example, a group containing units such as oxadiazole, triazine, triazole, oxazole, isoxazole, thiazole, isothiazole, thiadiazole, and quinoxalin can be used.
These charge transporting groups may have a substituent as long as the charge transporting property is not impaired. Examples of the substituent which may be possessed include an alkyl group, an alkoxy group, a carbonyl group, a cyano group, a trifluoromethyl group, a trimethylsilyl group and the like.

The charge-transporting group is preferably a hole-transporting group, more preferably a group containing a unit of a tertiary aromatic amine or carbazole.

Therefore, as the compound represented by the general formula (1), preferably Q is an aliphatic heterocyclic group containing a sulfur atom and a nitrogen atom as ring member atoms, X is a direct bond, and A is a third. A compound that is a charge-transporting residue containing a unit of a higher aromatic amine or carbazole.

Further, as a preferable structure of the compound represented by the general formula (1), compounds represented by the following general formulas (2) to (11) can be mentioned.

[In the general formula (2), R ^{1 to} R ¹⁴ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ¹ is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 1} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (3), R ^{15 to} R ²⁴ are independently hydrogen atoms, hydrocarbon groups which may have substituents, alkoxy groups which may have substituents, and substituents, respectively. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ² is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 2} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (4), R ^{25 to} R ³² are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ² is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 3} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (5), R ^{33 to} R ⁴⁰ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ⁴ is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 4} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (6), R ^{41 to} R ⁴³ independently represent a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a tro group or a trimethylsilyl group, and X ⁵ is an alkylene which may have a direct bond and a substituent. group, which may have a substituent alkyleneoxy carbonyl group, optionally having a substituent is also an arylene group or azomethine group, Q ⁵ is an optionally substituted thiazolidinyl group, a substituted A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (7), R ^{44 to} R ⁴⁶ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ⁶ is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 6} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (8), R ⁴⁷ and R ⁴⁸ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ⁷ is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 7} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (9), R ⁴⁹ and R ⁵⁰ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group or a trimethylsilyl group, and X ⁸ is an alkylene which may have a direct bond and a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 8} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (10), R ^{51 to} R ⁵⁵ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group, and a trimethylsilyl group, and X ⁹ is a direct bond and an alkylene which may have a substituent. A group, an alkyleneoxycarbonyl group which may have a substituent, an arylene group or an azomethine group which ^{may have a substituent, and Q 9} is a thiazolidinyl group which may have a substituent, a substituent. A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

[In the general formula (11), R ⁵⁶ and R ⁵⁷ are independent of each other, a hydrogen atom, a hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an amino group which may have a substituent, an alkylthio group which may have a substituent, a cyano group, a nitro group, and a trimethylsilyl group, and X ¹⁰ is a direct bond and an alkylene which may have a substituent. group, which may have a substituent alkyleneoxy carbonyl group, optionally having a substituent is also an arylene group or azomethine group, Q ¹⁰ is an optionally substituted thiazolidinyl group, a substituted A thiomorpholinyl group which may have a group, a tetrahydrothiopyranyl group which may have a substituent, or a 1,3-dithianyl group which may have a substituent. ]

The groups in the general formulas (2) to (11) will be described below.

The alkyl group is a monovalent residue obtained by formally removing one hydrogen atom from an alkane, and may be linear or branched. Specific examples of the alkyl group include a linear alkyl group such as a methyl group, an ethyl group, a hexyl group and a dodecyl group, and a branched alkyl group such as a 2-ethylhexyl group. The alkyl group preferably has 1 to 6 carbon atoms.

The alkoxy group is a group to which an alkyl group is bonded via an ether bond, and examples of the alkyl group include the above-mentioned alkyl group.

An amino group is a monovalent residue in which one hydrogen atom is formally removed from ammonia.

The alkylthio group is a group to which an alkyl group is bonded via a sulfide bond, and examples of the alkyl group include the above-mentioned alkyl group.

R ¹ , R ² , R ^{4 to} R ⁷ , R ^{9 to} R ¹⁶ , R ^{18 to} R ²¹ , R ^{23 to} R ²⁶ , and R ^{28 to} R ⁵⁷ are preferably hydrogen atoms. R ³ , R ⁸ , R ¹⁷ , and R ²² are preferably a hydrogen atom, an alkyl group, or an alkoxy group, and more preferably a hydrogen atom, a methyl group, or a methoxy group. R ²⁷ is preferably a hydrogen atom or an alkyl group, and more preferably an ethyl group.

The alkylene group is a divalent residue obtained by formally removing two hydrogen atoms from an alkane, and may be linear or branched. Specific examples of the alkylene group include a linear alkylene group such as a methylene group, a 1,2-ethylene group, a 1,6-hexylene group and a 1,12-dodecylene group, a 2-ethyl-1,6-hexylene group and the like. Examples include branched alkylene groups. The alkylene group preferably has 1 to 6 carbon atoms, more preferably 1 or 2 carbon atoms.

The arylene group is a divalent residue obtained by formally removing two hydrogen atoms from an aromatic hydrocarbon. Specific examples of the arylene group include a 1,2-phenylene group, a 1,3-phenylene group and 1 , 4-Phenylene group, 1,4-naphthylene group, 2,6-pyrenyl group and the like. The aryl group preferably has 6 to 10 carbon atoms, and more preferably 6.

The azomethine group is a ^{divalent residue represented by -CR 61} = N-, and R ⁶¹ is a hydrogen atom or the above alkyl group. R ⁶¹ is preferably a hydrogen atom.

The alkyleneoxycarbonyl group is a ^{divalent residue represented by -R 62} O (C = O) -, and R ⁶² is the above-mentioned alkylene group.

The thiazolidinyl group is a monovalent residue obtained by formally removing one hydrogen atom from thiazolidine, and examples thereof include 2-thiazolidinyl group, 3-thiazolidinyl group, 4-thiazolidinyl group, and 5-thiazolidinyl group. It is preferably a 2-thiazolidinyl group.

The thiomorpholinyl group is a monovalent residue obtained by formally removing one hydrogen atom from thiomorpholin, and is a 2-thiomorpholinyl group, a 3-thiomorpholinyl group, or a 4-thiomorpholi. Nyl group, 5-thiomorpholinyl group, 6-thiomorpholinyl group can be mentioned. It is preferably a 4-thiomorpholinyl group.

The tetrahydrothiopyranyl group is a monovalent residue obtained by formally removing one hydrogen atom from tetrahydropyran, and is a 2-tetrahydrothiopyranyl group, a 3-tetrahydrothiopyranyl group, or a 4-tetrahydrothiopyranyl group. Examples include a group, a 5-tetrahydrothiopyranyl group, and a 6-tetrahydrothiopyranyl group. It is preferably a 4-tetrahydrothiopyranyl group.

The 1,3-dithiane ring group is a monovalent residue obtained by formally removing one hydrogen atom from 1,3-dithiane, and is a (1,3-dithianyl) -2-yl group, (1,3). Examples thereof include −dithianyl) -4-yl group, (1,3-dithianyl) -5-yl group, and (1,3-dithianyl) -6-yl group. It is preferably a (1,3-dithianyl) -2-yl group.

Tables 1 to 4 give specific examples of the compounds represented by the general formula (1), but are not limited thereto.

The quantum dots of the present invention may be surface-treated with yet another known ligand in addition to the compound represented by the general formula (1). Further, quantum dots surface-treated with a known ligand other than the compound represented by the general formula (1) may be used in combination. As known ligands, for example, dodecanethiol, oleic acid, oleylamine, trioctylphosphine, trioctylphosphine oxide and the like can be used.

<Ink composition>
The ink composition of the present invention contains the quantum dots and the solvent according to the present invention, and may further contain other components if necessary. Since the ink composition of the present invention contains quantum dots having high stability, it has excellent stability over time and fluorescence quantum yield.
Hereinafter, each component contained in the ink composition will be described.

[solvent]
In this ink composition, the solvent can be appropriately selected from the solvents capable of dispersing the semiconductor fine particles, depending on the use of the ink composition and the like. Specific examples of the solvent include, for example, 1,2,3-trichloropropane, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-1, 3-Propanediol, 3,5,5-trimethyl-2-cyclohexene-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butandiol, 3- Methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N , N-dimethylacetamide, N, N-dimethylformamide, n-butyl alcohol, n-butylbenzene, n-propyl acetate, N-methylpyrrolidone, toluene, octane, nonane, hexane, o-xylene, o-chlorotoluene, o-diethylbenzene, o-dichlorobenzene, P-chlorotoluene, P-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, water, methanol, ethanol, isopropyl alcohol, tershal tarshalbutanol, isobutyl alcohol, isophorone , Ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotersial butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol Monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate , Diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyle -Tel, Dipropylene glycol methyl ether acetate, Dipropylene glycol monoethyl ether, Dipropylene glycol monobutyl ether, Dipropylene glycol monopropyl ether, Dipropylene glycol monomethyl ether, Diacetone alcohol, Triacetin, Tripropylene glycol monobutyl ether, Tripropylene glycol Monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol Examples thereof include monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methyl cyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid ester. These solvents may be used alone or in admixture of two or more at any ratio as required.

<Inkjet ink>
The ink composition of the present invention can be used as an inkjet ink used in an inkjet method by adjusting the viscosity using a solvent, a resin component described later, a polymerizable monomer, or the like. When used as an inkjet ink, it is preferable to adjust the viscosity at 25 ° C. to 3 to 50 mPa · s.

In the case of an inkjet ink, the solvent is selected from the viewpoints of solubility in the resin, swelling action on the device member, viscosity, and dryness of the ink in the nozzle, and the following solvents (A-1) and (A-2) are used. And (A-3), it is preferable to contain one or more kinds of organic solvents having a boiling point of 135 ° C. or higher at 760 mmHg.
Solvent (A-1): R ^1- (OC ₂ H ₄ ) m-OC (= O) -CH ₃
[However, R ¹ is an alkyl group having 1 to 8 carbon atoms, C ₂ H ₄ is a linear or branched ethylene chain, and 1 ≦ m ≦ 3. ]
Solvent (A-2): R ^2- (OC ₃ H ₆ ) p-OC (= O) -CH ₃
[However, R ² is an alkyl group having 1 to 8 carbon atoms, C ₃ H ₆ is a linear or branched propylene chain, and 1 ≦ p ≦ 3. ]
Solvent (A-3): Organic solvent having two or more acetate structures

Specific examples of the solvents (A-1) to (A-3) include, for example, propylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate, 1 , 3-butylene glycol diacetate, 1,6-hexanediol diacetate, triacetin and the like, but are not limited thereto. Of these, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, and 1,3-butylene glycol diacetate are preferable from the viewpoint of discharge stability.
Further, it is preferable that the content of the solvent having a boiling point of 135 ° C. or higher at 760 mmHg is 60% by mass or more in the total solvent from the viewpoint of ejection stability and ink drying property at the nozzle.

<Other ingredients>
The ink composition of the present invention comprises a resin, a cross-linking agent, a polymerizable monomer, a photosensitizer, a heat-sensitive substance, a photopolymerization initiator, and a photoacid generator, depending on the required performance according to the intended use. , Photobase generator, sensitizer and the like may be contained. The component can be used alone or in combination of two or more, and the content thereof is preferably 0 to 100 parts by mass with respect to 1 part by mass of the quantum dots. If it exceeds 100 parts by mass, the quantum dot content in the ink composition becomes low, and sufficient fluorescence intensity may not be obtained.
Further, the ink composition of the present invention can be a positive resist or a negative resist that can form a pattern by a photolithography method by containing a photosensitive substance or a polymerizable monomer.

[resin]
As the resin, a thermoplastic resin or a thermosetting resin can be used, for example, petroleum resin, maleic acid resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, rubber chloride, alkyd resin, acrylic resin, polyester. Examples thereof include resins, amino resins, vinyl resins, butyral resins and the like. The resin can be appropriately selected depending on the substrate on which the ink composition is printed.

[Crosslinking agent]
The cross-linking agent is preferably a thermally cross-linking agent, and is a melamine compound, a benzoguanamine compound, an acrylate-based monomer, a carbodiimide compound, an epoxy compound, an oxetane compound, a phenol compound, a benzoxazine compound, a blocked caric acid compound, and a blocked isocyanate compound. At least one selected from the group consisting of the silane coupling agent and the silane coupling agent is preferably used because of its excellent heat resistance.

[Polymerizable monomer]
The polymerizable monomer includes a monomer or an oligomer that is cured by ultraviolet rays, heat, or the like to form a resin, and these can be used alone or in combination of two or more.
Examples of the polymerizable monomer include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, and β-carboxyethyl. (Meta) acrylate, polyethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, Neopentyl glycol-modified trimethylolpropandi (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) ) Acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, tricyclodecanyl Various acrylic acid esters such as (meth) acrylate, ester acrylate, (meth) acrylic acid ester of methylolated melamine, epoxy (meth) acrylate, urethane acrylate, and methacrylic acid ester, (meth) acrylic acid, styrene, vinyl acetate, hydroxy Ethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-vinylformamide, acrylonitrile and the like can be mentioned, but are not necessarily limited thereto. .. These can be used alone or in admixture of two or more at any ratio as required.

[Heat-sensitive substances, light-sensitive substances]
Examples of the heat-sensitive substance include a thermal polymerization initiator, and specifically, an organic peroxide-based initiator, an azo-based initiator, and the like can be used. Examples of the photosensitive substance include a photopolymerization initiator, a photoacid generator, and a photobase generator.

[Photopolymerization initiator, photoacid generator]
Examples of the photopolymerization initiator include acetphenone-based compounds, benzoin-based compounds, benzophenone-based compounds, thioxanthone-based compounds, triazine-based compounds, oxime ester-based compounds, phosphine-based compounds, quinone-based compounds, borate-based compounds, and carbazole-based compounds. Examples thereof include imidazole-based compounds and titanosen-based compounds.
Examples of the photoacid generator include a sulfonium salt, a tetrahydrothiophenium salt, an N-sulfonyloxyimide compound and the like.

The photopolymerization initiator and / or photoacid generator is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. When it is within the above range, sufficient curability can be obtained, and coloring and other deterioration of physical properties do not occur, which is preferable.

[Photobase generator]
Examples of the photobase generator include a heterocyclic group-containing photobase generator, 2-nitrobenzylcyclohexylcarbamate, [[(2,6-dinitrobenzyl) oxy] carbonyl] cyclohexylamine, and bis [[(2-nitrobenzyl). ) Oxy] carbonyl] hexane-1,6-diamine, triphenylmethanol, o-carbamoyl hydroxylamide, o-carbamoyl oxime, hexaammine cobalt (III) tris (triphenyl methyl borate) and the like.

[Sensitizer]
Examples of the sensitizer include chalcone derivatives, unsaturated ketones typified by dibenzalacetone, 1,2-diketone derivatives typified by benzyl and camphorquinone, benzoin derivatives, fluorene derivatives, and naphthoquinone derivatives. Polymethine dyes such as anthraquinone derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, oxonoal derivatives, aclysin derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indolin Derivatives, azulene derivatives, azurenium derivatives, squarylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, tetrapyrazinoporphyrazine derivatives, phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalyloporphy Razine derivative, naphthalocyanine derivative, subphthalocyanine derivative, pyrylium derivative, thiopyrilium derivative, tetraphyllin derivative, anurene derivative, spiropyrane derivative, spiroxazine derivative, thiospiropyrane derivative, metal arene complex, organic ruthenium complex, or Michler ketone derivative, α-a Syroxyester, acylphosphine oxide, methylphenylglycolate, benzyl, 9,10-phenanthrene quinone, camphorquinone, ethyl anthraquinone, 4,4'-diethylisophthalofenone, 3,3', or 4, Examples thereof include 4'-tetra (t-butylperoxycarbonyl) benzophenone and 4,4'-diethylaminobenzophenone.

The ink composition of the present invention may contain components other than the above as long as the object of the present invention is not impaired. Examples of other components include antifoaming agents, leveling agents, thickeners and the like.

The base material for forming the quantum dot-containing layer using the ink composition of the present invention is not particularly limited, and for example, polycarbonate, hard vinyl chloride, soft vinyl chloride, polystyrene, foamed styrol, PMMA, polypropylene, polyethylene, etc. A plastic base material such as PET, a mixed or modified product thereof, a paper base material such as high-quality paper, art paper, coated paper, cast-coated paper, a glass base material, a metal base material such as stainless steel, and the like can be used. The base material can be appropriately selected depending on the use of the ink composition. Further, as a method of forming a quantum dot-containing layer on a base material using the ink composition of the present invention, a method of forming a quantum dot-containing layer by drying a solvent after applying the ink composition, or an ink Examples thereof include a method of forming a cured film by irradiating the composition with ultraviolet rays after coating.

<Light wavelength conversion layer>
The quantum dot-containing layer can be used as an optical wavelength conversion layer. The optical wavelength conversion layer can convert the excitation light into fluorescence on the long wavelength side and emit it, and there is no particular limitation as long as the relationship between the excitation light wavelength and the emitted fluorescence wavelength can be maintained. Can be used as the excitation light to obtain green or red fluorescence, or ultraviolet light or visible light can be used as the excitation light to obtain fluorescence in the near infrared region. The thickness of the light wavelength conversion layer is preferably 1 to 500 μm, more preferably 1 to 50 μm, and even more preferably 1 to 10 μm. A thickness of 1 μm or more is preferable because a high wavelength conversion effect can be obtained. Further, when the thickness is 500 μm or less, the light source unit can be thinned when incorporated in the light source unit, which is preferable.

<Light wavelength conversion member>
The above-mentioned light wavelength conversion layer can also be used as an optical wavelength conversion member.
The light wavelength conversion member is one in which a light wavelength conversion layer is formed on at least one surface of a base material. The base material is not particularly limited, but for example, a plastic base material such as polycarbonate, hard vinyl chloride, soft vinyl chloride, polystyrene, foamed styrol, PMMA, polypropylene, polyethylene, PET, a mixed or modified product thereof, high-quality paper, art paper, coated paper, etc. , Paper base material such as cast coated paper, metal base material such as glass and stainless steel can be used. The base material can be appropriately selected depending on the intended use. For example, in the case of prepaid cards, passable cards, etc., a plastic base material or a mixed or modified product thereof is preferable from the viewpoint of durability. If it is a one-dimensional bar code, a two-dimensional bar code, or a QR code (registered trademark) (matrix type two-dimensional code) as an information recording medium, a plastic base material or a paper base material is preferable. Further, if it is a color filter for wavelength conversion, a transparent substrate is preferable.

<Electroluminescent element>
The electroluminescent device of the present invention includes an anode, a light emitting layer, and a cathode on a substrate, and the light emitting layer includes the quantum dots according to the present invention as a light emitting material. The electroluminescent device of the present invention is excellent in reliability because the light emitting layer contains the quantum dots having excellent stability according to the present invention. The electroluminescent device of the present invention has at least a substrate, an anode, a light emitting layer, and a cathode, and may further have another layer if necessary. Further, the light emitting layer may be a single layer or a plurality of layers, and when there are two or more light emitting layers, at least one layer may contain the light emitting material according to the present invention.

That is, examples of the electroluminescent device of the present invention include a single-layer electroluminescent device including an anode, a light emitting layer, and a cathode, and a multi-layered electroluminescent device including another layer. As other layers constituting the multi-layer electroluminescent element, in addition to the light emitting layer, it is easy to inject holes and electrons into the light emitting layer, and the recombination of holes and electrons in the light emitting layer is facilitated. Examples thereof include a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like, which are intended to be used by an electron. Further, as another layer, it exists adjacent to the light emitting layer between the light emitting layer and the anode, and has a role of separating the light emitting layer and the anode, or the light emitting layer from the hole injection layer or the hole transport layer. An interlayer layer, which is a layer, and the like can be mentioned.

Typical layer configurations of the multi-layer electric field light emitting element include (1) anode / hole injection layer / light emitting layer / cathode, (2) anode / hole injection layer / hole transport layer / light emitting layer / cathode, and (1) 3) anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode, (5) anode / hole injection Layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (6) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (7) anode / Light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode (9) anode / hole injection layer / hole transport layer / interlayer layer / light emitting layer / cathode , (10) Electron / hole injection layer / interlayer layer / light emitting layer / electron injection layer / cathode, (11) anode / hole injection layer / hole transport layer / interlayer layer / light emitting layer / electron injection layer / Examples include a cathode.

Further, each of the above-mentioned layers may be formed by a layer structure of two or more layers, or several layers may be repeatedly laminated. As such an example, in recent years, for the purpose of improving the light extraction efficiency, an element configuration called "multi-photon emission" in which a part of the above-mentioned multi-layer electroluminescent layers is multi-layered has been proposed. This is, for example, in an electroluminescent element composed of a glass substrate / anode / hole transport layer / electron transporting light emitting layer / electron injection layer / charge generating layer / light emitting layer / cathode, of the charge generating layer / light emitting layer. Examples thereof include units in which a plurality of layers are laminated.

[Hole injection layer]
As the hole injection layer, a hole injection material that exhibits an excellent hole injection effect on the light emitting layer and can form a hole injection layer having excellent adhesion to the anode interface and thin film formation is used. Further, when such a material is laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated in multiple layers, the materials used for each are referred to as a hole injection material and a hole transport material. Sometimes. These hole injection materials and hole transport materials need to have a large hole mobility and a small ionization energy of usually 5.5 eV or less. As such a hole injection layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable, and further ^{, when an electric field with a hole mobility of, for example, 10 4} to 10 ⁶ V / cm is applied, at least It is preferably 10 ^-6 cm ² / V · sec. The hole injection material and the hole transport material are not particularly limited as long as they have the above-mentioned preferable properties, and are conventionally used as a hole charge transport material in an optical transmission material or an organic EL device. Any known material used for the hole injection layer can be selected and used.

Examples of such hole injection materials and hole transport materials include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, and amino-substituted chalcone derivatives. , Oxazole derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative, stilben derivative, silazane derivative, polysilane-based, aniline-based copolymer, conductive polymer oligomer (particularly thiophene oligomer) disclosed in JP-A 1-211399. ) Etc. can be mentioned.

Further, as the hole injection material and the hole transport material, a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound can also be used. For example, 4,4'-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two fused aromatic rings in the molecule described in US Pat. No. 5,061,569 and the like. , 4,4', 4 "-tris (N- (3-methylphenyl) -N-phenyl" in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. Examples thereof include amino) triphenylamines, and phthalocyanine derivatives such as copper phthalocyanine and hydrogen phthalocyanine can also be mentioned as hole injection materials. Further, aromatic dimethyridene compounds, p-type Si, p-type SiC, etc. Inorganic compounds can also be used as hole injection materials and hole transport materials.

Further, materials that can be used for the hole injection layer include molybdenum oxide (MnO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), copper oxide (CuO _x ), tungsten oxide (WO _x ), and iridium oxide. Inorganic oxides such as (IrO _x ) and their dopes are also mentioned.

Specific examples of the aromatic tertiary amine compound include, for example, N, N'-diphenyl-N, N'-(3-methylphenyl) -1,1'-biphenyl-4,4'-diamine, N, N, N', N'-(4-methylphenyl) -1,1'-phenyl-4,4'-diamine, N, N, N', N'-(4-methylphenyl) -1,1' -Biphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-dinaphthyl-1,1'-biphenyl-4,4'-diamine, N, N'-(methylphenyl) -N, N'-(4-n-butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, N, N'-bis ( 4'-diphenylamino-4-biphenylyl) -N, N'-diphenylbenzidine, N, N'-bis (4'-diphenylamino-4-phenyl) -N, N'-diphenylbenzidine, N, N'- Bis (4'-diphenylamino-4-phenyl) -N, N'-di (1-naphthyl) benzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N , N'-diphenylbenzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N, N'-di (1-naphthyl) benzidine and the like. It can be used as both a hole injection material and a hole transport material.

To form the hole injection layer, the above-mentioned compound is thinned by a known method such as a vacuum deposition method, a spin coating method, a casting method, or a Langmuir-Bloget method (LB method). The film thickness of the hole injection layer is not particularly limited, but is usually 5 nm to 5 μm.

Examples of the material used for the interlayer layer include polyvinylcarbazole and its derivatives, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and polymers containing aromatic amines such as triphenyldiamine derivatives. Further, as a method of forming an interlayer layer, when a high molecular weight material is used, a method of forming a film from a solution is exemplified.

For the film formation of the interlayer layer from the solution, known wet film forming methods such as spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, etc. A coating method such as a dip coating method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, an inkjet printing method, a capillary coating method, or a nozzle coating method can be used.

The optimum value of the thickness of the interlayer layer differs depending on the material used, and it may be selected so that the driving voltage and the luminous efficiency are appropriate values. Usually, it is 1 nm to 1 μm, preferably 2 to 500 nm. More preferably, it is 5 to 200 nm.

[Electron injection layer]
As the electron injection layer, an electron injection material that exhibits an excellent electron injection effect on the light emitting layer and can form an electron injection layer having excellent adhesion to the cathode interface and thin film formation is used. Examples of such electron-injected materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthracinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fleolenilidenemethane. Examples thereof include derivatives, antron derivatives, silol derivatives, triarylphosphine oxide derivatives, polyquinolin and its derivatives, polyquinoxalin and its derivatives, polyfluorene and its derivatives, calcium acetylacetonate, sodium acetate and the like. Inorganic / organic composite materials in which a metal such as cesium is doped with vasophenanthroline (Proceedings of the Society of Polymer Science, Vol. 50, No. 4, p. 660, published in 2001) and the 50th Joint Lecture on Applied Physics. Proceedings of the lecture, No. BCP, TPP, T5MPyTZ, etc. described on page 3, 1402, published in 2003 can also be mentioned as examples of electron injection materials, but can form a thin film necessary for device fabrication, inject electrons from a cathode, and transport electrons. As long as it is a material, it is not particularly limited to these.

Among the electron-injected materials, preferred ones include a metal complex compound, a nitrogen-containing five-membered ring derivative, a siror derivative, and a triarylphosphine oxide derivative. As a preferable metal complex compound, a metal complex of 8-hydroxyquinoline or a derivative thereof is suitable. Specific examples of the metal complex of 8-hydroxyquinolin or a derivative thereof include tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinate) aluminum, and tris (4-methyl-8-). Hydroxyquinolinate) Aluminum, Tris (5-methyl-8-Hydroxyquinolinate) Aluminum, Tris (5-phenyl-8-Hydroxyquinolinate) Aluminum, Bis (8-Hydroxyquinolinate) (1-naphtholate) ) Aluminum, bis (8-hydroxyquinolinate) (2-naphtholate) Aluminum, bis (8-hydroxyquinolinate) (phenolate) aluminum, bis (8-hydroxyquinolinate) (4-cyano-1-naphtholate) ) Aluminum, bis (4-methyl-8-hydroxyquinolinate) (1-naphtholate) aluminum, bis (5-methyl-8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (5-phenyl-8) -Hydroxyquinolinate) (phenolate) aluminum, bis (5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) aluminum, bis (8-hydroxyquinolinate) chloroaluminum, bis (8) -Aluminum complex compounds such as hydroxyquinolinate (o-cresolate) aluminum, tris (8-hydroxyquinolinate) gallium, tris (2-methyl-8-hydroxyquinolinate) gallium, tris (4-methyl- 8-Hydroxyquinolinate) gallium, tris (5-methyl-8-hydroxyquinolinate) gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinate) gallium, bis (2-methyl-8) -Hydroxyquinolinate) (1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (2-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (phenolate) gallium , Bis (2-methyl-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2,4-dimethyl-8-hydroxyquinolinate) (1-naphtholate) gallium, bis (2) , 5-Dimethyl-8-Hydroxyquinolinate) (2-naphtholate) gallium, bis (2-methyl-5-phenyl-8-hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-5-si) Anno-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) chlorogallium, bis (2-methyl-8-hydroxyquinolinate) ( In addition to gallium complex compounds such as o-cresolate) gallium, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, bis (10-hydroxybenzo [h] ] Kinolinate) Metal complex compounds such as berylium, bis (8-hydroxyquinolinate) zinc, and bis (10-hydroxybenzo [h] quinolinate) zinc can be mentioned.

Further, preferred examples of the nitrogen-containing five-membered ring derivative include an oxadiazole derivative, a thiazole derivative, an oxadiazole derivative, a thiadiazole derivative, and a triazole derivative. Specifically, 2,5-bis (1-phenyl) -1, 3,4-Oxadiazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1-phenyl) -1,3,4-oxadiazole, 2- (4) '-Tert-butylphenyl) -5- (4 "-biphenyl) 1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, 1,4 -Bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4'-tert-butyl Phenyl) -5- (4 "-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1,3,4-thiadiazole, 1,4-bis [2-( 5-Phenylthiazolyl)] Benzene, 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl)- Examples thereof include 1,3,4-triazole and 1,4-bis [2- (5-phenyltriazolyl)] benzene.

Further, examples of the material that can be used for the electron injection layer include _{inorganic oxides such as zinc oxide (ZnO x} ) and titanium oxide (TiO _x ), and their dopes.

Further, as the hole blocking layer, a hole blocking material that can prevent holes that have passed through the light emitting layer from reaching the electron injection layer and can form a layer having excellent thin film forming property is used. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinate) (4-phenylphenolate) aluminum and bis (2-methyl-8-hydroxyquinolinate) ( Examples thereof include gallium complex compounds such as 4-phenylphenolate) gallium and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[Light emitting layer]
As the light emitting layer of the electroluminescent element, one having the following functions is preferable.
Injection function: A function that can inject holes from the anode or hole injection layer when an electric field is applied, and can inject electrons from the cathode or electron injection layer. Transport function; electric charge (electrons and holes) injected Function to move by the force of light emission function; A function to provide a field for recombination of electrons and holes and connect this to light emission However, there is a difference between the ease of hole injection and the ease of electron injection. Also, the transport capacity represented by the mobility of holes and electrons may be large or small.

At least one light emitting layer constituting the electroluminescent device of the present invention contains a light emitting material composed of the quantum dots of the present invention. The light emitting layer containing the light emitting material is preferably formed from the ink composition of the present invention. Further, the light emitting layer may contain a known light emitting material in addition to the quantum dots of the present invention. As known light emitting materials that may be added to the ink composition of the present invention, fluorescent whitening agents such as benzothiazole, benzimidazole, and benzoxazole, metal chelated oxinoid compounds, and styrylbenzene compounds can be used. .. Specific examples of these compounds include compounds disclosed in Japanese Patent Application Laid-Open No. 59-194393. Yet other useful compounds are listed in Chemistry of Synthetic Soybeans (1971), pp. 628-637 and 640.

Examples of the metal chelated oxinoid compound include 8-hydroxyquinoline-based metal complexes such as tris (8-quinolinol) aluminum and dilithium epintridione as suitable compounds.

Further, as the styrylbenzene-based compound, a distyrylpyrazine derivative or a polyphenyl-based compound can also be used as a material for the light emitting layer.

Further, in addition to the above-mentioned fluorescent whitening agent, metal chelating oxynoid compound, styrylbenzene compound and the like, for example, 12-phthaloperinone, 1,4-diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl -1,3-butadiene, naphthalimide derivative, perylene derivative, oxadiazole derivative, aldazine derivative, pyrazirin derivative, cyclopentadiene derivative, pyrolopyrrole derivative, styrylamine derivative, coumarin compound, International Publication No. WO90 / 13148 and Appl .. Phys. Lett. , Vol 58, 18, P1982 (1991), polymer compounds, 9,9', 10,10'-tetraphenyl-2,2'-bianthracene, PPV (polyparaphenylene vinylene) derivatives, Examples thereof include polyfluorene derivatives and copolymers thereof having structures of the following general formulas (12) to (14).

[In the general formula (12), R ^x1 and R ^X2 each independently represent a monovalent aliphatic hydrocarbon group, and n1 represents an integer of 3 to 100. ]

[In general formula (13), R ^x3 and R ^X4 each independently represent a monovalent aliphatic hydrocarbon group, and n2 and n3 each independently represent an integer of 3 to 100. ]

[In the general formula (14), R ^X5 and R ^X6 each independently represent a monovalent aliphatic hydrocarbon group, and n4 and n5 each independently represent an integer of 3 to 100. Ph represents a phenyl group. ]

_{Further, the general formula (Rs-Q) 2-} Al-O-L3 [in the formula, L3 is a hydrocarbon having 6 to 24 carbon atoms including a phenyl moiety, which is described in JP-A-5-258862, etc. O-L3 is a phenolate ligand, Q indicates a substituted 8-quinolinolate ligand, and Rs sterically indicates that the substituted 8-quinolinolate ligand is bonded to an aluminum atom in excess of two. Also included are compounds represented by [showing 8-quinolinolate ring substituents selected to interfere]. Specific examples thereof include bis (2-methyl-8-quinolinolate) (para-phenylphenolate) aluminum (III) and bis (2-methyl-8-quinolinolate) (1-naphtholate) aluminum (III). ..

[anode]
As the material used for the anode of the electroluminescent element, a material having a large work function (4 eV or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au and conductive materials such as _{CuI, ITO, SnO 2, and ZnO.} In order to form this anode, these electrode materials can be formed into a thin film by a method such as a vapor deposition method or a sputtering method. When the light emitted from the light emitting layer is taken out from the anode, it is desirable that the anode has a characteristic that the transmittance of the anode with respect to the light emitted is larger than 10%. Further, the sheet resistance of the anode is preferably several hundreds of Ω / □ or less. Further, the film thickness of the anode is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm, although it depends on the material.

[cathode]
As the material used for the cathode of the electroluminescent element, a metal having a small work function (4 eV or less), an alloy, an electrically conductive compound, or a mixture thereof is used as an electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloys, magnesium, lithium, magnesium / silver alloys, aluminum / aluminum oxide, aluminum / lithium alloys, indium, rare earth metals and the like. This cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Here, when the light emitted from the light emitting layer is taken out from the cathode, the transmittance of the cathode with respect to the light emitted is preferably larger than 10%. The sheet resistance of the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

As for the method for producing the electroluminescent device, the anode, the light emitting layer, the hole injection layer if necessary, and the electron injection layer if necessary may be formed by the above materials and methods, and finally the cathode may be formed. .. Further, the electroluminescent device can be manufactured from the cathode to the anode in the reverse order of the above.

The electroluminescent device is made on a translucent substrate. The translucent base material is a substrate that supports an electroluminescent element, and its translucency is preferably such that the light transmittance in the visible region of 400 to 700 nm is 50% or more, preferably 90% or more. It is preferable to use a smoother base material.

These base materials are not particularly limited as long as they have mechanical and thermal strength and are transparent, and may be a flexible film or sheet-like base material. As the base material, for example, a glass plate, a synthetic resin plate, or the like is preferably used. Examples of the glass plate include plates formed of soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz and the like. Examples of the synthetic resin plate include plates such as polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyether sulfide resin, and polysulfon resin.

As a method for forming each layer of the electroluminescent element, either a dry film forming method such as vacuum deposition, electron beam irradiation, sputtering, plasma, or ion plating, or a wet film forming method such as spin coating, dipping, or flow coating. Method can be applied. Further, a method such as LITI (Laser Induced Thermal Imaging), printing (offset printing, flexographic printing, gravure printing, screen printing), inkjet or the like can also be applied. However, the light emitting layer is preferably formed by a wet film forming method.

The organic layer is particularly preferably a molecular deposition film. A molecular deposition film is a thin film deposited and formed from a material compound in a vapor phase state, or a film solidified and formed from a material compound in a solution state or a liquid phase state. It can be classified from the thin film (molecular cumulative film) formed by the LB method by the difference in aggregated structure and higher-order structure, and the functional difference caused by the difference. An organic layer can also be formed by dissolving a binder such as a resin and a material compound in a solvent to prepare a solution, and then thinning the solution by a spin coating method or the like. The film thickness of each layer is not particularly limited, but if the film thickness is too thick, a large applied voltage is required to obtain a constant light output, resulting in inefficiency. On the contrary, if the film thickness is too thin, pinholes, etc. Is generated, and it becomes difficult to obtain sufficient emission brightness even when an electric field is applied. Therefore, the film thickness of each layer is preferably in the range of 1 nm to 1 μm, but more preferably in the range of 10 nm to 0.2 μm.

Further, in order to improve the stability of the electroluminescent element with respect to temperature, humidity, atmosphere and the like, a protective layer may be provided on the surface of the element, or the entire element may be coated or sealed with a resin or the like. In particular, when coating or sealing the entire device, a photocurable resin that is cured by light is preferably used.

The current applied to the electroluminescent element is usually direct current, but pulse current or alternating current may be used. The current value and voltage value are not particularly limited as long as they do not destroy the element, but considering the power consumption and life of the element, it is desirable to efficiently emit light with as little electric energy as possible.

The electroluminescent element can be driven not only by the passive matrix method but also by the active matrix method. Further, as a method of extracting light from the electroluminescent element of the present invention, not only a method of bottom emission which extracts light from the anode side but also a method of top emission which extracts light from the cathode side can be used.

The main methods of the full-color electroluminescent element are a three-color painting method, a color conversion method, and a color filter method. Examples of the three-color painting method include a vapor deposition method using a shadow mask, an inkjet method, and a printing method. A laser thermal transfer method can also be used. The color conversion method is a method of converting from blue to green and red having a longer wavelength than blue through a color conversion (CCM) layer in which a fluorescent dye is dispersed by using a light emitting layer that emits blue light. The color filter method is a method of extracting light of three primary colors through a color filter for liquid crystal using an organic EL element that emits white light. In addition to these three primary colors, a part of white light is extracted as it is and used for light emission. As a result, the light emission efficiency of the entire element can be increased.

Further, the electroluminescent element may adopt a microcavity structure. This is because the organic EL element has a structure in which a light emitting layer is sandwiched between an anode and a cathode, and the emitted light causes multiple interference between the anode and the cathode, but the reflectance and transmission of the anode and the cathode are transmitted. It is a technology that positively utilizes the multiple interference effect and controls the emission wavelength extracted from the element by appropriately selecting the optical characteristics such as the rate and the thickness of the organic layer sandwiched between them. .. This also makes it possible to improve the emission chromaticity.

As described above, the electroluminescent device using the quantum dots of the present invention is excellent in fluorescence quantum yield and reliability. Therefore, the electroluminescent element can be used as a flat panel display such as a wall-mounted television or various flat light emitting bodies. It can also be applied to light sources such as copiers and printers, light sources such as liquid crystal displays and instruments, display boards, indicator lights and the like.

<Photoelectric conversion element>
The photoelectric conversion element of the present invention has the photoelectric conversion layer between a pair of electrodes. In the photoelectric conversion element of the present invention, a known configuration of the photoelectric conversion element can be applied. Further, the photoelectric conversion element of the present invention can be manufactured by a known method except for the photoelectric conversion layer.

Here, a photoelectric conversion element that can be produced by using the ink composition of the present invention will be described in detail. Generally, a photoelectric conversion element using semiconductor particles is composed of at least a pair of electrodes and a photoelectric conversion layer. For the purpose of improving the photoelectric conversion efficiency, various types of device structures have been proposed depending on the energy matching between the electrode and the semiconductor particles and the method for producing the photoelectric conversion layer composed of the semiconductor particles. For example, the ink composition of the present invention can be used to produce a photoelectric conversion element having the following known configurations.

1. 1. Schottky type photoelectric conversion element A photoelectric conversion element that obtains photovoltaic power by using a Schottky barrier formed at the interface between an electron-donating (p-type) or electron-accepting (n-type) semiconductor particle and an electrode. .. For example, when a p-type photoelectric conversion layer is used, a Schottky barrier is formed at the interface between the pair of electrodes and the electrode having the smaller internal work function, and charge separation occurs at the interface to perform photoelectric conversion. ..

2. Bilayer heterojunction photoelectric conversion element Electron donating (p-type) and electron-accepting (n-type) semiconductor particles and other semiconductor materials are individually formed between a pair of electrodes, and light charges are applied to the pn junction interface. It is a photoelectric conversion element that causes separation and obtains a photocurrent.

3. 3. Bulk heterojunction type photoelectric conversion element An organic semiconductor layer is formed by mixing electron-donating (p-type) and electron-accepting (n-type) semiconductor particles and other semiconductor materials at an arbitrary ratio between a pair of electrodes. At this time, the p-type and n-type materials may be uniformly dispersed or non-uniform. Since photocharge separation occurs at the interface formed by each p-type material and n-type material, the pn junction can be formed wider than that of the bilayer heterojunction type.

<Electrode>
It is preferable that at least one of the pair of electrodes constituting the photoelectric conversion element transmits light. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, and indium tin oxide (ITO), or gold, silver, platinum, chromium, nickel, lithium, indium, aluminum, calcium, and magnesium. And the like, and examples thereof include a mixture or a laminate of these metals and a conductive metal oxide.

The shape of the electrode is generally flat, but may be corrugated, pyramid, comb, or the like in order to improve energy conversion efficiency. As a method for forming these electrodes, a general electrode forming method can be used, and a PVD method such as a vacuum deposition method, a sputtering method, and an ion plating method, a CVD method, a chemical reaction method (sol-gel method, etc.), and casting can be used. Examples thereof include a method, a spray coating method, an inkjet method, and a spin coating method.

The photoelectric conversion element may include a layer other than the photoelectric conversion layer between the pair of electrodes, and has the hole injection layer, the hole transport layer, the electron transport layer, and / or the electron injection layer. You may.

The photoelectric conversion element may include other constituent members in addition to the above-mentioned layers. For example, an optical film (filter) that does not transmit ultraviolet rays may be provided. Ultraviolet rays have high energy and contribute to deterioration of organic materials. By blocking this ultraviolet ray, the life of the element can be extended.

A protective film may be provided for the purpose of protecting the photoelectric conversion layer from an external impact. The protective film is, for example, a polymer film such as styrene resin, epoxy resin, acrylic resin, polyurethane, polyimide, polyvinyl alcohol, polyvinylidene fluoride, polyethylene polyvinyl alcohol copolymer, or an inorganic oxide film such as silicon oxide, silicon nitride, or aluminum oxide. It can be composed of a nitride film, a metal plate or metal foil such as aluminum, or a laminated film thereof. As the material of these protective films, only one kind may be used, or two or more kinds may be used.

Generally, it is said that semiconductor fine particles are deteriorated by moisture and oxygen in the air. A barrier film may be provided to prevent this. For example, metals or inorganic oxides are preferable, and Ti, Al, Mg, Zr, silicon oxide, aluminum oxide, silicon nitride, aluminum oxide, magnesium oxide, zinc oxide, indium oxide, tin oxide, yttrium oxide, boron oxide, etc. Calcium oxide and the like can be mentioned. There is no particular order in which these various functional films are laminated, and a functional film having these functions may be used.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention. Unless otherwise specified, "parts" and "%" in Examples and Comparative Examples represent "parts by mass" and "% by mass". The mass average molecular weight (Mw) is a value obtained by measuring using GPC and converting into polystyrene.

<Synthesis of compound represented by general formula (1)>
(Synthesis of Compound 1)
After adding 80 parts of methanol, 5.5 parts of 4- (N, N-diphenylamino) benzaldehyde and 1.8 parts of 2-aminoethanethiol to the eggplant flask, the mixture was heated under reflux for 3 hours. After distilling off methanol under reduced pressure, the obtained crude product was recovered by filtration and washed with methanol. The obtained solid was dried under reduced pressure to obtain Compound 1. The yield was 99%.

(Synthesis of Compound 2)
After adding 80 parts of methanol, 6.6.0 parts of 4- (N, N-di-p-tolylamino) benzaldehyde, and 1.8 parts of 2-aminoethanethiol to an eggplant flask, the mixture was heated under reflux for 3 hours. After distilling off methanol under reduced pressure, the obtained crude product was recovered by filtration and washed with methanol. The obtained solid was dried under reduced pressure to obtain Compound 2. The yield was 88%.

(Synthesis of compound 3)
After adding 80 parts of methanol, 6.7 parts of 4- (bis (p-methoxyphenyl) amino) benzaldehyde, and 1.8 parts of 2-aminoethanethiol to an eggplant flask, the mixture was heated under reflux for 3 hours. After distilling off methanol under reduced pressure, the obtained crude product was recovered by filtration and washed with methanol. The obtained solid was dried under reduced pressure to obtain Compound 3. The yield was 93%.

(Synthesis of Compound 4)
After adding 80 parts of methanol, 5.2 parts of 9-ethyl-3-carbazolecarboxyaldehyde and 1.8 parts of 2-aminoethanethiol to the eggplant flask, the mixture was heated under reflux for 3 hours. After distilling off methanol under reduced pressure, the obtained crude product was recovered by filtration and washed with methanol. The obtained solid was dried under reduced pressure to obtain Compound 4. The yield was 95%.

Table 5 shows the obtained compounds 1 to 4 and the compounds 0 and 19 used in the comparative examples.

<Manufacturing of resin>
[Preparation of resin solution 1]
70 parts of mecitylene was placed in a reaction vessel equipped with a thermometer, a cooling tube, a nitrogen gas introduction tube, and a stirrer in a separable 4-neck flask, the temperature was raised to 80 ° C., the inside of the reaction vessel was replaced with nitrogen, and then n from the dropping tube. A mixture of 18 parts of −butyl methacrylate, 12 parts of methyl methacrylate and 0.4 parts of 2,2′-azobisisobutyronitrile was added dropwise over 2 hours. After completion of the dropping, the reaction was continued for another 3 hours to obtain a solution of an acrylic resin having a mass average molecular weight (Mw) of 26,000. After cooling to room temperature, about 2 g of the resin solution was sampled and dried by heating at 180 ° C. for 20 minutes to measure the non-volatile content, and mesitylene was added to the previously synthesized resin solution so that the non-volatile content was 30% by mass. Acrylic resin solution 1 was prepared.

[Preparation of resin solution 2]
70 parts of diethylene glycol monobutyl ether acetate (DBCA) was charged into a reaction vessel equipped with a thermometer, a cooling pipe, a nitrogen gas introduction pipe, and a stirrer in a separable 4-neck flask, the temperature was raised to 80 ° C., and the inside of the reaction vessel was replaced with nitrogen. Then, a mixture of 14 parts of n-butyl methacrylate, 10 parts of methyl methacrylate, 6 parts of styrene, and 0.4 part of 2,2′-azobisisobutyronitrile was added dropwise from the dropping tube over 2 hours. After completion of the dropping, the reaction was continued for another 3 hours to obtain a solution of an acrylic resin having a mass average molecular weight (Mw) of 26,000. After cooling to room temperature, about 2 g of the resin solution is sampled and dried by heating at 180 ° C. for 20 minutes to measure the non-volatile content. Diethylene glycol monobutyl ether acetate so that the non-volatile content is 30% by mass in the previously synthesized resin solution. Was added to prepare an acrylic resin solution 2.

[Preparation of resin solution 3]
200 parts of norbornene, 50 parts of cyclopentene, 180 parts of 1-hexene and 750 parts of toluene were placed in a nitrogen-substituted reaction vessel and heated to 60 ° C. This was modified with 0.62 parts of a toluene solution of triethylaluminum (1.5 mol / l) and tert-C ₄ H ₉ OH / CH ₃ OH (tert-C ₄ H ₉ OH / CH ₃ OH / WCl ₆ = _{Add 3.7 parts of WCl 6} solution (concentration: 0.05 mol / l) (0.35 / 0.3 / 1; molar ratio), heat and stir at 80 ° C. for 3 hours, ring-open polymerization reaction, hydrogenation. The reaction was carried out, and then the non-volatile content was adjusted to 30% using trimethylbenzene to obtain a cyclopentadiene resin solution 3.

<Preparation of quantum dot PbS-0>
First, as a sulfur source solution, 0.40 parts of elemental sulfur and 6.0 parts of oleylamine were heated to 120 ° C. in a nitrogen atmosphere in a reaction vessel to form a uniform solution, and then cooled to 25 ° C. Next, as a lead source solution, 0.32 parts of lead chloride and 6.0 parts of oleylamine were heated to 120 ° C. in another reaction vessel under a nitrogen atmosphere. Then, after preparing the lead source solution at 40 ° C., 1.8 parts of the above sulfur source solution was added at once. After reacting for 30 seconds, the container was immersed in an ice bath to quench it, and then diluted with 13 parts of hexane. After centrifuging (4000 rpm, 5 minutes) to remove unreacted raw materials, 12 parts of a mixed solution of butanol: methanol = 2: 1 (volume ratio) was added to precipitate the quantum dots, and then centrifuged (4000 rpm). 5 minutes) to recover the quantum dots. Then, 24 parts of a mixed solution consisting of hexane: oleic acid = 1: 2 (volume ratio) was added, and the mixture was stirred for 30 minutes, centrifuged, and the supernatant was recovered. Quantum dot sedimentation, redispersion, and impurity sedimentation are repeated twice, and finally the quantum dots are precipitated, vacuum dried, and then adjusted to a solid content concentration of 5% using n-octane to obtain quantum dots PbS-0. (Average particle size 3.5 nm).

<Synthesis of quantum dots PbSe-0>
As a lead source solution, 0.22 parts of lead oxide, 0.73 parts of oleic acid, and 10 parts of 1-octadecene were heated to 150 ° C. in a reaction vessel under a nitrogen atmosphere. Then, a mixture of 2.5 parts of 1M-trioctylphosphine-selenium solution and 0.028 parts of diphenylphosphine was quickly added, the reaction solution was heated to 180 ° C., kept at 160 ° C., and reacted for 2 minutes. After that, the reaction solution was rapidly cooled. After diluting with 10 parts of hexane, it was precipitated with acetone. The precipitate was washed 5 times with acetone and vacuum dried to obtain quantum dots PbSe-0 (average particle size 2.7 nm).

<Synthesis of quantum dot Ag ₂ S-0>
0.04 parts of silver oleate, 8 parts of octanethiol, and 4 parts of dodecylamine were heated in a reaction vessel at 200 ° C. for 0.5 hours in an Ar atmosphere. After allowing this solution to cool to room temperature, 40 parts of absolute ethanol was added. The obtained mixture was centrifuged and vacuum dried to obtain quantum dots Ag ₂ S-0 (average particle size 2.5 nm).

<Manufacturing of quantum dots>
[Comparative Example 0] (Quantum Dot QD-0)
An additive solution was prepared by heating and dissolving 0.55 parts of acetic anhydride, 7.0 parts of dodecanethiol (Compound 0), and 5.0 parts of oleylamine. Separately, 0.22 parts of indium chloride and 8.25 parts of octylamine were placed in a reaction vessel and heated to 165 ° C. while performing nitrogen bubbling. After the indium chloride was dissolved, 0.86 part of diethylaminophosphine was injected in a short time and controlled at 165 ° C. for 20 minutes. After that, it was rapidly cooled and cooled to 40 ° C. The above additive solution was injected, heated at 240 ° C. for 2 hours, and then allowed to cool to room temperature. After allowing to cool, purification was carried out by a reprecipitation method using hexane and ethanol. The precipitate was recovered and dried under reduced pressure to obtain quantum dot QD-0 in which core-shell type semiconductor fine particles having an InP core and a ZnS shell were surface-treated with dodecanethiol (Compound 0).

[Example 1] (Quantum dot QD-1)
Quantum dots QD-0 were dispersed in toluene to give a solid content concentration of 1%. The same amount of a toluene solution of 5% compound 1 as the diluted solution was added, and the mixture was stirred for 12 hours. Purification was carried out by the reprecipitation method using toluene and methanol. The precipitate was recovered and dried under reduced pressure to obtain quantum dot QD-1 surface-treated with compound 1.

[Examples 2 to 4, Comparative Example 1] (Quantum Dot QD-2 to 5)
Quantum dots QD-2 to 5 were prepared in the same manner as QD-1 except that the compounds were changed to compounds 2 to 4 and 19 shown in Table 6.

<Preparation of ink composition>
[Example 101] (Ink composition 1)
Two parts of quantum dots (QD-1) and 38 parts of n-hexane were mixed in a container that could be sealed. Then, the mixture was hermetically sealed and stirred, and filtered using a membrane filter having a pore size of 1 μm to obtain an ink composition 1.

[Examples 102 to 104, Comparative Example 101] (Ink Compositions 2 to 4, 9)
Ink compositions 2 to 4 and 9 were prepared in the same manner as ink composition 1 except that the quantum dots and the solvent were weighed in this order in a container that could be sealed with the compounding composition shown in Table 7.

[Example 105] (Ink composition 5)
In a container that can be sealed, 2 parts of quantum dots (QD-1), 60 parts of resin solution 1, and 68 parts of diethylene glycol monobutyl ether acetate (DBCA) were mixed. Then, the mixture was hermetically sealed and stirred, and filtered using a membrane filter having a pore size of 1 μm to obtain an ink composition 5.

[Examples 106 to 108] (ink compositions 6 to 8)
Ink compositions 6 to 8 were prepared in the same manner as in ink composition 5 except that the quantum dots, the resin solution, and the solvent were weighed in this order in a container that can be sealed with the compounding composition shown in Table 7.

<Evaluation of ink composition>
The following evaluation was carried out on the obtained ink composition. The results are shown in Table 7.

[Stability over time]
The stability over time was evaluated based on the following criteria by visually observing the appearance of the ink composition after storing it in an environment of 40 ° C. for 7 days.
A: No sediment (usable)
C: With sediment (cannot be used)

[Fluorescence quantum yield (QY) maintenance rate]
First, the thickness after drying was used on a transparent film (polyester film Lumirror 75S10 manufactured by Toray Industries, Inc.) using the ink composition after being stored for 7 days in the environment of 40 ° C. used for the evaluation of stability over time. The film was coated with a bar coater so as to have a thickness of 6.0 μm, and dried at 100 ° C. for 10 minutes to obtain a printed matter. Next, the fluorescence quantum yield of the ink composition and the printed matter was measured under the following conditions. When the fluorescence quantum yield of the ink composition was 1, the ratio of the fluorescence quantum yield of the printed matter was defined as the fluorescence quantum yield maintenance rate, and the evaluation was made according to the following criteria. The fluorescence quantum yield retention rate is preferably close to 1, and if it is 0.6 or more, it can be practically used.
A: Fluorescence quantum yield maintenance rate is 0.6 or more (usable)
C: Fluorescence quantum yield maintenance rate is less than 0.6 (cannot be used)
≪Fluorescence quantum yield measurement conditions≫
Measuring machine: Quantum efficiency measurement system QE-2000 manufactured by Otsuka Electronics Co., Ltd. Excitation wavelength: 400 nm Integration range 375-425 nm
Fluorescence integration range: 430-800 nm

[Dischargeability]
An ejection test was carried out on the ink composition using an inkjet printer (Materials Printer "DMP-2831" manufactured by Fuji Film Dimatix Co., Ltd., cartridge: Dimatix Materials Cartriges, 10 pL). In the ejection test, the ink composition was ejected continuously for 30 seconds. The ejection head portion of the inkjet printer has 16 nozzles, and the ejection property was evaluated based on the following criteria from the number of nozzles capable of continuous ejection.
A: Continuous discharge is possible with 10 or more nozzles (can be discharged)
C: The number of nozzles capable of continuous discharge is 9 or less (poor discharge)

<Manufacturing of electroluminescent elements>
[Example 201]
(Manufacturing of electroluminescent element)
Unless otherwise specified, vapor deposition (vacuum vapor deposition) was performed in ^{a vacuum of 10-6} Torr under conditions where temperature control such as heating and cooling of the substrate was not performed. The light emitting characteristics of the element were measured using an electroluminescent element having a light emitting element area of 2 mm × 2 mm.
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, CLEVIOUS (registered trademark) PVP CH8000 manufactured by Heraeus) is spin-coated on the cleaned glass plate with ITO electrode. It was coated by the method and dried at 110 ° C. for 20 minutes to obtain a hole injection layer having a film thickness of 35 nm. Next, poly (N-vinylcarbazole) was dissolved in monochlorobenzene at a concentration of 1.0% by mass, coated by a spin coating method, dried at 110 ° C. for 20 minutes, and holes having a film thickness of 35 nm. A transport layer was formed. On it, the obtained ink composition 1 was diluted 35 times and applied by a spin coating method, held for 5 minutes in a nitrogen atmosphere at room temperature and dried to form a 20 nm light emitting layer. .. On it, an isopropanol dispersion of zinc oxide manufactured by Avantama N-10 was applied by a spin coating method, and heat-dried on a hot plate at 80 ° C. for 20 minutes to form an electron transport layer of 80 nm. .. Finally, 200 nm of aluminum was vapor-deposited to form an electrode to obtain an electroluminescent device. When the obtained electroluminescent element was driven at a current density of 10 (mA / cm ² ), it was confirmed that it emitted green light.

<Preparation of ink composition>
<Example 301>
Quantum dots PbS-0 were prepared in a toluene solution having a solid content concentration of 1%. After mixing 1 part of the prepared solution and 1 part of the 5% toluene solution of Compound 1, the mixture was stirred for 12 hours. Purification was carried out by the reprecipitation method using toluene and ethanol. The precipitate was vacuum dried and octane was added to prepare an ink composition PbS-1 as a 5% solution of octane.

<Examples 302 to 306, Comparative Examples 301 to 303>
_{PbS-2 to 4, PbSe-1, and Ag 2} S-1, respectively, were prepared in the same manner as in Example 301, except that compound 1 was changed to the compound shown in Table 8. Of these, PbS-2 to 4, PbSe-1 and Ag ₂ S-1 are the ink compositions of the present invention, and PbS-5, PbSe-2 and Ag ₂ S-2 are the ink compositions of the present invention. Is not a composition.

<Example 401>
(Manufacturing of photoelectric conversion element)
The production and evaluation of the photoelectric conversion element will be described below. The vapor deposition was ^{carried out in a vacuum of 10-6} Torr under the condition that the temperature was not controlled such as heating and cooling of the substrate. The evaluation of the element was measured using a photoelectric conversion element having an element area of 2 mm × 2 mm. First, spin PEDOT / PSS (poly (3,4-ethylenedioxy) -2.5-thiophene / polystyrene sulfonic acid, CLEVIOUS (registered trademark) PVP CH8000 manufactured by Heraeus) on a cleaned glass plate with an ITO electrode. It was coated by a coating method and dried at 110 ° C. for 20 minutes to obtain a hole injection layer having a thickness of 35 nm. The ink composition PbS-1 was applied onto the hole injection layer by a spin coating method to form a photoelectric conversion layer having a thickness of 150 nm. Next, a ZnO dispersion N-10 manufactured by Avantama was formed on the photoelectric conversion layer by spin coating to form an electron transport layer having a thickness of 50 nm. Next, aluminum (hereinafter referred to as Al) was vapor-deposited on the electron transport layer to a thickness of 200 nm to form an electrode to obtain a photoelectric conversion element.

(Evaluation of photoelectric conversion element)
The durability of the obtained device was evaluated by the method shown below. Durability was calculated by measuring the IV curves of the device before and after storage and calculating the ratio of these measured values (measured value after storage / measured value before storage). The IV curve of the cell uses xenon lamp white light as the light source (PEC-L01 manufactured by Pexel Technologies Co., Ltd.) and emits light at a light intensity (100 mW / cm ² ) equivalent to sunlight (AM1.5). Under a mask with an irradiation area of 0.0363 cm ² (2 mm square), a scanning speed of 0.1 V / sec (0.01 Vstep) using an IV characteristic measuring device (PECK2400-N, manufactured by Pexel Technologies Co., Ltd.). The measurement was performed under the conditions of a waiting time of 50 msec after setting the voltage, a measurement integration time of 50 msec, a start voltage of −0.1 V, and an end voltage of 1.1 V. For durability, the IV curve was measured before storage (immediately after device fabrication) and after storage of the photoelectric conversion element for 4 days under the conditions of shading, 25 ° C., and humidity 60%, and before storage (immediately after device fabrication). It was calculated as the ratio of the conversion efficiency after storage to the conversion efficiency of.
(Evaluation criteria)
⊚: Ratio 95% or more: Good ○: Ratio 90% or more and less than 95%: Practically usable Δ: Ratio 80% or more and less than 90%: Practically unusable ×: Ratio less than 80%: Defective

<Examples 402 to 406>
Photoelectric conversion elements were produced and evaluated in the same manner as in Example 401, except that PbS-2 to 4, PbSe-1, and Ag _{2 S-1 were used instead of PbS-1 used in Example 401.} did. The results are shown in Table 9.

<Comparative Examples 401 to 403>
Photoelectric conversion elements were prepared and evaluated in the same manner as in Example 401, except that PbS-5, PbSe-2, and Ag _{2 S-2 were used instead of PbS-1 used in Example 301.} The results are shown in Table 9.

In Table 7, the ink composition of the present invention using quantum dots surface-treated with a ligand having an aliphatic heterocyclic moiety containing a sulfur atom and a charge transporting moiety has excellent temporal stability and fluorescence quantum yield. It showed the maintenance rate and showed high reliability. Table 9 also showed high durability of the photoelectric conversion element using quantum dots surface-treated with a ligand having an aliphatic heterocyclic moiety containing a sulfur atom and a charge transporting moiety.
Regarding the above results, the mechanism of action is not clear, but the aliphatic heterocyclic group containing a sulfur atom has better oxidation resistance than the alkylthio group in benzenethiol of the comparative example, so that the ligand is peeled from the quantum dot. It is presumed that it was suppressed and the above effect was exhibited. Ligand peeling reduces the dispersibility of quantum dots and causes a decrease in sedimentation stability, defect formation on the quantum dot surface, and a decrease in fluorescence quantum yield due to oxidation. Will be done.
Further, since the ink composition has good quantum dot stability, it has an inkjet ejection property and can be used as an inkjet ink. Further, the quantum dots of the present invention can be used as an electroluminescent device.

Claims (8)

Quantum dots, which are semiconductor fine particles having a compound represented by the following general formula (1) on the surface.
General formula (1)

[In the general formula (1), Q is an aliphatic heterocyclic group containing a sulfur atom, X is a direct bond or a divalent linking group, and A is a charge transporting group. ] The quantum dot according to claim 1, wherein the semiconductor fine particles include a compound semiconductor. The quantum dot according to claim 1 or 2, wherein the semiconductor fine particles are of a core-shell type. The quantum dot according to any one of claims 1 to 3, wherein the charge transporting group is a hole transporting group. An ink composition containing the quantum dots according to any one of claims 1 to 4 and a solvent. The ink composition according to claim 5, which is used in an inkjet method. An electroluminescent device comprising an anode, a light emitting layer, and a cathode on a substrate, wherein the light emitting layer contains the quantum dots according to any one of claims 1 to 4. A photoelectric conversion element having a photoelectric conversion layer between a pair of electrodes, wherein the photoelectric conversion layer contains the quantum dots according to any one of claims 1 to 4.