Quantum dot-containing composition, method for manufacturing the same, and wavelength conversion member

Abstract

To provide a quantum dot-containing composition, a method for manufacturing the composition, and a wavelength conversion member which can increase the stability while maintaining characteristics of a quantum dot, suppress such negative reactions as thickening or generation of residuals, and can perform patterning.SOLUTION: The quantum dot-containing composition includes a quantum dot which emits fluorescence by excitation light, the quantum dot-containing composition being a mixture of the quantum dot and a polymerizable polymer composition. The surface of the quantum dot includes a surface coating layer having a siloxane bond. The content of a free thiol group in the surface coating layer is 4.0 mmol at most for 1 gram of the quantum dot.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a quantum dot-containing composition, a method for producing the same, and a wavelength conversion member. [Background technology]

[0002] In single crystal semiconductor nanoparticles, when the size of the crystal is equal to or smaller than the Bohr radius of the exciton, a strong quantum confinement effect occurs, and the energy levels become discrete. The energy levels depend on the size of the crystal, and the light absorption wavelength and emission wavelength can be adjusted by the crystal size. In addition, the quantum confinement effect makes the light emission by exciton recombination in single crystal semiconductor nanoparticles highly efficient, and since the light emission is basically an emission line, if a uniform particle size distribution can be achieved, it will be possible to emit light with high brightness and narrow bandwidth, which has attracted attention. The phenomenon caused by the strong quantum confinement effect in such nanoparticles is called the quantum size effect, and semiconductor nanocrystals that utilize this property are being studied as quantum dots for wide application.

[0003] One application of quantum dots is being considered for use as phosphor materials for displays. If narrow-band, highly efficient light emission can be achieved, it will be possible to express colors that could not be reproduced with existing technology, and so quantum dots are attracting attention as a next-generation display material.

[0004] One display in which quantum dots are currently being used is the quantum dot liquid crystal display, which is already being commercialized. Attempts are being made to convert the color of light irradiated from white light or blue LED backlights to green or red by passing the light through a quantum dot-containing wavelength conversion material. The surface of quantum dots is active, and the quantum yield gradually decreases due to moisture and oxygen in the air, so improving the stability of quantum dot-containing wavelength conversion materials is an essential item to consider.

[0005] Various studies have been conducted on the stabilization of wavelength conversion members containing quantum dots. One example is gas barrier sealing. The stability is improved by forming an inner layer in which quantum dots are dispersed in an amphiphilic polymer or a compatible polymer, and then dispersing them in another resin layer with low gas permeability. Patent Document 1 discloses a method in which quantum dots (QDs) are dispersed in a hydrophobic resin layer to form polymer beads, and the polymer beads are surface-modified so that they are dispersed in a hydrophilic polymer, and then dispersed in the hydrophilic polymer. Hydrophilic polymers tend to have higher gas barrier properties than hydrophobic polymers, so QDs are dispersed in such a two-layer or multi-layer structure. However, since the gas barrier properties are insufficient for use in applications that may be subject to high temperature and high humidity environments such as those used in liquid crystal display units, a method is used in which the QD film is sandwiched between gas barrier films to remove the effects of oxygen and water vapor.

[0006] Various studies have been conducted on the method of producing polymer beads. Patent Document 2 discloses a method in which QD-containing polymer beads are produced from polysiloxane having an amino group and a polymerizable functional group, and then a polymer having another polymerizable functional group is mixed, emulsified, and further cured. In this method, it is possible to increase the adhesion with the QD by using a polymer to which a ligand that coordinates to the QD surface is introduced, thereby increasing the concentration of QD contained in the polymer beads and improving stability. However, the stability is still insufficient with this method, and the beads are implemented by sandwiching them between barrier films.

[0007] Using a barrier film not only increases costs, but also inevitably increases thickness. Currently, there is a demand for thinner LCDs, and it is necessary to reduce the thickness of the wavelength conversion material, so there is a demand for improved stability without the barrier film. In addition, when considering color filter applications, patterning is required, and it is not realistic to provide a protective layer such as a barrier film, so the stability of the quantum dots themselves is necessary.

[0008] Patent Document 3 has been published as a study on improving heat resistance and moisture resistance without using a barrier film. In this method, a silazane coating process is further performed on the multilayer resin composition using the polymer bead structure of Patent Document 1, and stability is improved. However, this method has a problem in that the quantum yield decreases when the silazane coating is photocured by irradiation with short ultraviolet light (170 nm).

[0009] In addition, Patent Document 4 has been published as another attempt. In this method, a ligand is coordinated to the quantum dot, a reactive substituent such as a vinyl group or a methacryl group is introduced to the ligand, and then a Si-H-containing silicone resin and a curing agent are mixed, and the mixture is spin-coated as is and cured by heating to produce a film with improved heat resistance and moisture resistance. However, the Si-H-containing silicone resin and quantum dots used have low compatibility, and aggregation occurs when attempting to disperse them at a high concentration. Therefore, compatibility must be improved by ligand treatment, but there is a problem that if the balance between the hydrophobic group and the hydrophilic group changes when the ligand is coordinated, aggregation is likely to occur and the quantum yield decreases.

[0010] In addition, when applying to color filters, it is important to form a quantum dot surface state suitable for the patterning method. Currently, photolithography is used to form color filters by applying a photosensitive resin composition containing a pigment onto a glass substrate, drying the solvent, exposing the composition to a mask with UV irradiation, and removing the uncured parts by alkaline development to form color patterns. This process is repeated to form blue, red, and green patterns. The photolithography method has many problems, such as a large loss of raw materials because the uncured parts are wasted, and the process is complicated and expensive equipment is used. For this reason, inkjet methods have been considered in recent years. With the inkjet method, there is no loss of raw materials, and it is possible to produce large-sized and large-area products without introducing expensive equipment, making it competitive in terms of cost. However, the technology to make fine nozzles is difficult, and there are problems such as clogging and unstable discharge when the nozzle becomes smaller, so both proven photolithography and cost-competitive inkjet are being considered for miniaturization.

[0011] On the other hand, in both photolithography and inkjet printing, it is difficult to prepare a resin composition containing quantum dots at a high concentration and high dispersion. Resin compositions are dispersed in polar solvents such as PGMEA and PGME, with some exceptions. Quantum dots are basically hydrophobic, and are difficult to disperse in these solvents and resin materials, and tend to aggregate, making it difficult to prepare a photosensitive resin composition containing quantum dots at a high concentration and high dispersion. As a countermeasure, the addition of a dispersant has been considered, but this has problems such as reducing the quantum dot content and altering the properties of the resin after curing. In addition, heating is generally performed when volatilizing the solvent, but this can cause problems with dark reactions such as poor curing, thickening, and the generation of residues due to the influence of impurities contained in the quantum dots. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 9,708,532 [Patent Document 2] JP 2016-111292 A [Patent Document 3] Special Publication No. 2019-536653 [Patent Document 4] U.S. Patent Publication No. 20190322926 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made in consideration of the above-mentioned problems, and provides a patternable quantum dot-containing composition that maintains the properties of quantum dots while improving stability and suppressing dark reactions such as thickening and residue generation, as well as a method for producing the same and a wavelength conversion member. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides a quantum dot-containing composition that contains quantum dots that emit fluorescence in response to excitation light, the quantum dot-containing composition being a mixture of the quantum dots and a polymerizable polymer composition, the surfaces of the quantum dots contain a surface coating layer having a siloxane bond, and the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots.

[0015] Such a quantum dot-containing composition maintains the properties of the quantum dots while improving stability and suppressing dark reactions such as thickening and residue generation, making it possible to form a quantum dot-containing composition that can be patterned.

[0016] In this case, the content of the free thiol groups contained in the surface coating layer is preferably 3.0 mmol or less per 1 g of the quantum dots.

[0017] Such a quantum dot-containing composition is preferable because it is more likely to prevent poor curing.

[0018] In this case, the content of the free thiol groups contained in the surface coating layer is preferably 1.0 mmol or less per 1 g of the quantum dots.

[0019] Such a quantum dot-containing composition is preferable because it can further suppress the dark reaction.

[0020] In this case, it is preferable that the surface coating layer has at least one reactive substituent selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group.

[0021] Such reactive substituents are preferred because they prevent aggregation of the quantum dots.

[0022] In this case, it is preferable that the polymerizable polymer contained in the polymerizable polymer composition has one or more polymerizable substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group.

[0023] Such a group can be suitably used as the polymerizable substituent.

[0024] The present invention also provides a wavelength conversion member which is a cured product of the quantum dot-containing composition described above.

[0025] Such a wavelength conversion material maintains the properties of the quantum dots, improves stability, and suppresses dark reactions such as thickening and residue generation, making it possible to form a patternable wavelength conversion material.

[0026] The present invention also provides a method for producing the above-described quantum dot-containing composition, which contains quantum dots that emit fluorescence when exposed to excitation light, comprising the steps of: a ligand exchange step of mixing a solution in which the quantum dots are dispersed with a ligand having a substituent that forms a siloxane bond, and coordinating the ligand to the outermost surface of the quantum dots; a surface coating layer forming step of forming a surface coating layer by reacting the substituent that forms a siloxane bond with a compound that reacts with the substituent that forms a siloxane bond to generate a polysiloxane, after the ligand exchange step; a purification step of purifying the surface coating layer so that the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots by purification after the surface coating layer formation step; The present invention provides a method for producing a quantum dot-containing composition, the method including a polymerizable polymer composition mixing step of mixing the quantum dots coated with the surface coating layer with the polymerizable polymer composition after the purification step.

[0027] Such a method for producing a quantum dot-containing composition can improve stability while maintaining the properties of the quantum dots, and can suppress dark reactions such as thickening and residue generation, thereby making it possible to produce a quantum dot-containing composition that can be patterned. Effect of the Invention

[0028] As a result of intensive research into the above-mentioned problems, it was found that forming a surface coating layer containing siloxane inactivates the composition and improves its stability. Furthermore, by suppressing the content of free thiol groups in order to suppress the dark reaction with the polymerizable polymer composition, it is possible to prepare a quantum dot-containing composition that can be cured without inhibiting curing or generating residues even when added at a high concentration. As a result, in a reliability test at 85°C and 85% RH without a barrier film, the decrease rate of the internal quantum efficiency after 250 hours of treatment was suppressed to within 10%, making it possible to stabilize the composition. In addition, the dark reaction with the polymerizable polymer composition is suppressed, making it possible to realize a quantum dot-containing composition that is excellent in patternability and curability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] As described above, there has been a need for the development of a patternable quantum dot-containing composition that maintains the properties of quantum dots while improving stability and suppressing dark reactions such as thickening and residue generation, a method for producing the same, and a wavelength conversion member.

[0030] As a result of extensive investigations into the above-mentioned problems, the inventors discovered that the above-mentioned problems could be solved by setting the content of free thiol groups to 4.0 mmol or less per gram of quantum dots, and thus completed the present invention.

[0031] That is, the present invention relates to a quantum dot-containing composition that contains quantum dots that emit fluorescence when exposed to excitation light, the quantum dot-containing composition being a mixture of the quantum dots and a polymerizable polymer composition, the surfaces of the quantum dots contain a surface coating layer having a siloxane bond, and the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots.

[0032] The present invention will be described in detail below, but the present invention is not limited thereto.

[0033] (Quantum dot-containing composition) The quantum dot-containing composition of the present invention is a quantum dot-containing composition containing quantum dots that emit fluorescence when excited by excitation light, the quantum dot-containing composition is a mixture of the quantum dots and a polymerizable polymer composition, the surface of the quantum dots contains a surface coating layer having a siloxane bond, and the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots. That is, a surface coating layer is formed on the surface of the quantum dots, and a composite particle and a mixture thereof are formed in which a substituent that undergoes condensation polymerization with the polymerizable polymer composition or a polymerizable substituent is introduced into the skeleton structure substituent ligand of the polymerizable polymer composition.

[0034] (Quantum dots) The quantum dots in the present invention are not particularly limited as long as they emit fluorescence when excited by excitation light, and can be used in any form. Quantum dots are mainly nanoparticles of 10 nm or less, but they can also be nanowires, nanorods, nanotubes, nanocubes, etc., and any form can be used.

[0035] The quantum dots used in the present invention can be made of any suitable material, for example, a semiconductor material selected from the group consisting of II-VI group, III-V group, IV group, IV-VI group, I-III-VI group, II-IV-V group, mixed crystals or alloys thereof, or compounds having a perovskite structure.

[0036] Specific examples of compounds include, but are not limited to, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, Si, Ge, Sn, Pb, PbS, PbSe, PbTe, SnS, SnSe, SnTe, AgGaS2, AgInS2, AgGaSe2, AgInSe2, CuGaS2, CuGaSe2, CuInS2, CuInSe2, ZnSiP2, ZnGeP2, CdSiP2, CdGeP2, CsPbCl3, CsPbBr3, CsPbI3, CsSnCl3, CsSnBr3, and CsSnI3.

[0037] In addition, the quantum dots used in the present invention can have a core-shell structure. The shell material capable of forming the core-shell structure is not particularly limited, but is preferably one having a large band gap and low lattice mismatch with respect to the core material, and can be arbitrarily combined according to the core material. Specific shell materials include ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, BeS, BeSe, BeTe, MgS, MgSe, MgTe, PbS, PbSe, PbTe, SnS, SnSe, SnTe, CuF, CuCl, CuBr, CuI, etc., and the above materials may be selected as a single or multiple mixed crystals, but are not limited thereto.

[0038] There are various methods for producing quantum dots, such as a liquid phase method and a gas phase method, and the method is not particularly limited in the present invention. However, from the viewpoint of exhibiting high fluorescence emission efficiency, it is preferable to use semiconductor nanoparticles obtained by a hot soap method or a hot injection method, in which a precursor species is reacted at high temperature in a nonpolar solvent with a high boiling point, and it is desirable that an organic ligand is coordinated to the surface in order to impart dispersibility in the nonpolar solvent and reduce surface defects.

[0039] From the viewpoint of dispersibility, the ligand preferably contains an aliphatic hydrocarbon. Examples of such ligands include oleic acid, stearic acid, palmitic acid, myristic acid, lauric acid, decanoic acid, octanoic acid, oleylamine, stearyl (octadecyl)amine, dodecyl (lauryl)amine, decylamine, octylamine, octadecanethiol, hexadecanethiol, tetradecanethiol, dodecanethiol, decanethiol, octanethiol, trioctylphosphine, trioctylphosphine oxide, triphenylphosphine, triphenylphosphine oxide, tributylphosphine, and tributylphosphine oxide, and the like, and these may be used alone or in combination.

[0040] (Ligands with substituents that coordinate to quantum dots) In addition, in the quantum dots contained in the quantum dot-containing composition of the present invention, it is desirable that in addition to the above-mentioned ligands, a ligand having a substituent that forms a siloxane bond is coordinated.As the ligand having a substituent that forms a siloxane bond, it is desirable to have a substituent that interacts or adsorbs on the quantum dot surface.As the substituent that adsorbs or reacts on the quantum dot surface, an amino group, a carboxy group, a mercapto group, a phosphine group, a phosphine oxide group, a sulfonyl group, a quaternary ammonium salt, etc. can be mentioned, among which, from the viewpoint of the strength of coordination, an amino group, a carboxy group, a mercapto group, a phosphine group, and a quaternary ammonium salt are preferred.

[0041] Examples of the substituent that forms a siloxane bond include compounds containing alkoxysilanes such as trimethoxysilyl, triethoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, dimethylmethoxysilyl, and ethoxydimethylsilyl groups, compounds having a silazane bond, compounds having a Si-OH bond, compounds having a Si-X (X: halogen) bond, and carboxylic acids. However, it is preferable to use alkoxysilanes, silazanes, and ligands containing Si-OH because the reaction can proceed under mild conditions that do not generate acids as by-products of the reaction.

[0042] (Surface coating layer) The quantum dot-containing composition of the present invention contains a surface coating layer having siloxane bond on the quantum dot surface. At this time, it is preferable to coat the quantum dot surface with a polymer by polysiloxane. Therefore, it is preferable to form a quantum dot surface coating layer containing polysiloxane by reacting with the substituent that forms siloxane bond contained in the ligand that has a substituent that coordinates with the quantum dot.

[0043] In addition, the surface coating layer of the quantum dots contained in the quantum dot-containing composition of the present invention preferably has at least one or more substituents (reactive substituents) that polymerize with the polymerizable polymer contained in the polymerizable polymer composition described below. The substituent that polymerizes with the polymerizable polymer is preferably contained in the surface coating layer by forming a covalent bond. This is because it is less likely to come off during the subsequent purification operation compared to when it forms an association with the surface-coated quantum dots or when it is contained so as to be coordinated to the quantum dot surface or surface coating layer.

[0044] Examples of the substituent that polymerizes with the polymerizable polymer include a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, an epoxy group, a sulfonyl group, a carboxyl group, and a thiol group. Since aggregation is less likely to occur, one or more reactive substituents selected from the group consisting of a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group are preferred.

[0045] In addition, it has been revealed that if the surface coating layer contains more than 4.0 mmol of free thiol groups per 1 g of quantum dots, a dark reaction occurs with the reactive substituents, resulting in curing inhibition or the generation of residues. Therefore, the amount of free thiol groups must be 4.0 mmol or less per 1 g of quantum dots, preferably 3.0 mmol or less, and more preferably 1.0 mmol or less. Thiol is often used during the synthesis of quantum dots, and is contained as a ligand in most quantum dots. Free thiol groups that are not coordinated to the quantum dot surface can be removed by purification, but if purification is insufficient, they remain on the quantum dot surface and cause dark reactions. If the amount of free thiol groups is 3.0 mmol or less per 1 g of quantum dots, curing inhibition does not occur, which is preferable.

[0046] (Polymerizable polymer composition) The quantum dot-containing composition of the present invention is a mixture of quantum dots and a polymerizable polymer composition, and the polymerizable polymer composition contains a polymerizable polymer as a base polymer and a polymerization initiator, and may also contain an organic solvent, a polymerizable crosslinking agent, a photoacid generator, an antioxidant, a light scattering agent, and the like. As the polymerizable polymer, a polymer derived from acrylic acid, methacrylic acid, an acrylic acid ester, or a methacrylic acid ester, a copolymer combining a plurality of polymers, a polymer having glycidyl (meth)acrylate as a repeating unit, a polymer containing a siloxane skeleton, a urethane skeleton, a silphenylene skeleton, a norbornene skeleton, a fluorene skeleton, or an isocyanurate skeleton can be suitably used, and the polymer to be used may be selected appropriately according to the application. For example, acrylic resin, alkyd resin, melamine resin, epoxy resin, silicone resin, polyvinyl alcohol, polyvinylpyrrolidone, polyamide, polyamide-imide, polyimide, and other polyimide precursors and their esterification products, and reaction products of tetracarboxylic dianhydride and diamine can be mentioned. In addition, a polymerizable substituent is introduced into these polymerizable polymers, and they can be cured by using them in combination with a polymerization initiator. Examples of radically polymerizable substituents include vinyl groups, acrylic groups, methacrylic groups, and thiol groups, and any of these can be used suitably. Examples of cationic polymerizable substituents include hydroxyl groups, phenolic hydroxyl groups, epoxy groups, glycidyl groups, oxetanyl groups, and isocyanate groups, and any of these can be used suitably. In addition, a carboxyl group may be introduced to impart alkaline developability. Among these, it is preferable to have at least one polymerizable substituent selected from vinyl groups, acrylic groups, methacrylic groups, hydroxyl groups, phenolic hydroxyl groups, and epoxy groups.

[0047] It is also preferable that the quantum dot-containing composition of the present invention contains a polymerization initiator. The polymerization initiator may be a thermal or photopolymerization initiator, and either may be suitably used in accordance with the base polymer. As the photoradical polymerization initiator, in the Irgacure (registered trademark) series commercially available from BASF, for example, Irgacure 290, Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, Irgacure 1173, etc. may be mentioned. In addition, in the Darocure (registered trademark) series, for example, TPO, Darocure 1173, etc. may be mentioned. In addition, the composition may contain a known thermal radical polymerization initiator or a photocationic polymerization initiator.

[0048] The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, and more preferably 0.2 to 5 parts by mass, based on 100 parts by mass of the polymerizable polymer to be added.

[0049] The quantum dot-containing composition of the present invention may contain a solvent to improve its applicability. As the solvent, an organic solvent is preferable from the viewpoint of compatibility with the quantum dots, for example, ketone, alkylene glycol ether, alcohol, and aromatic compound. From the group of ketones, acetone, methyl ethyl ketone, cyclohexanone, etc., and from the group of alkylene glycol ethers, methyl cellosolve (ethylene glycol monomethyl ether), butyl cellosolve (ethylene glycol monobutyl ether), methyl cellosolve acetate, cellosolve acetate, butyl cellosolve acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol dimethyl ether, diethylene glycol ethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, diethylene glycol methyl acetate. Suitable examples of the alcohols that can be used include ethers, diethylene glycol ethyl ether acetate, diethylene glycol propyl ether acetate, diethylene glycol isopropyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol tert-butyl ether acetate, triethylene glycol methyl ether acetate, triethylene glycol ethyl ether acetate, triethylene glycol propyl ether acetate, triethylene glycol isopropyl ether acetate, triethylene glycol butyl ether acetate, and triethylene glycol tert-butyl ether acetate; and from the alcohol group, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and 3-methyl-3-methoxybutanol; and from the aromatic compound group, benzene, toluene, and xylene can be suitably used.

[0050] In addition, the quantum dot-containing composition of the present invention may further contain a polymerizable crosslinking agent, a photoacid generator, an antioxidant, a light scattering agent, etc., and although there are no particular limitations, it is preferable that the agent does not affect the coatability of the quantum dot-containing composition.

[0051] (Method of producing a quantum dot-containing composition) The present invention provides a method for producing the above-described quantum dot-containing composition, which contains quantum dots that emit fluorescence when exposed to excitation light, comprising the steps of: a ligand exchange step of mixing a solution in which the quantum dots are dispersed with a ligand having a substituent that forms a siloxane bond, and coordinating the ligand to the outermost surface of the quantum dots; a surface coating layer forming step of forming a surface coating layer by reacting the substituent that forms a siloxane bond with a compound that reacts with the substituent that forms a siloxane bond to generate a polysiloxane, after the ligand exchange step; a purification step of purifying the surface coating layer so that the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots by purification after the surface coating layer formation step; The present invention provides a method for producing a quantum dot-containing composition, the method including a polymerizable polymer composition mixing step of mixing the quantum dots coated with the surface coating layer with the polymerizable polymer composition after the purification step.

[0052] The quantum dot-containing composition of the present invention can be produced, for example, by the following method. First, quantum dots coordinated with ligands containing long-chain hydrocarbons are dispersed in a hydrophobic solvent to obtain a solution in which quantum dots are dispersed, and the solution is mixed with a ligand having a substituent that forms a siloxane bond and a substituent that coordinates to the surface of the quantum dots to perform ligand exchange. The conditions of the ligand exchange reaction, such as the amount of ligand added, heating temperature, time, and light irradiation, are appropriately changed depending on the type of ligand.

[0053] Next, the quantum dots coordinated with a ligand having a substituent that forms a siloxane bond are reacted with a compound that reacts with the substituent that forms the siloxane bond to generate a polysiloxane, and a reaction to form a polysiloxane is performed to form a surface coating layer containing a siloxane bond. Although a sol-gel method can be suitably used as a general method for forming a polysiloxane bond, since quantum dots are vulnerable to acidic conditions and moisture, a sol-gel method under basic conditions is preferable, and a non-hydrolytic sol-gel method using diphenylsilanediol, tetramethyldisiloxanediol, etc. is more preferable. In addition, it is preferable that the surface coating layer on the surface of the quantum dots contained in the quantum dot-containing composition of the present invention has at least one or more substituents (reactive substituents) that polymerize with the polymerizable polymer contained in the polymerizable polymer composition described above or a skeletal structure of a similar structure. It is preferable that the substituents that polymerize with the polymerizable polymer or the compound having a similar skeletal structure are contained in the surface coating layer by forming a covalent bond. There are no particular limitations on the method for forming the covalent bond, but for example, a method in which a substituent that polymerizes with a polymerizable polymer or a substituent that forms a siloxane bond is introduced into a compound having a similar skeletal structure, and the introduced substituent is added during the above-mentioned non-hydrolytic sol-gel reaction, thereby forming a covalent bond and incorporating the resulting compound in the surface coating layer, or a method in which a substituent that polymerizes with a polymerizable polymer contained in a polymerizable polymer composition during the above-mentioned non-hydrolytic sol-gel reaction is introduced, and then a polymerizable polymer or monomer is reacted to introduce the resulting compound into the surface coating layer, can be suitably used.

[0054] After forming the surface coating layer, unreacted materials are removed by purification, and the content of free thiol groups contained in the surface coating layer is reduced to 4.0 mmol or less per 1 g of the quantum dots. The quantum dots coated with the surface coating layer are then mixed with a polymerizable polymer composition to produce a quantum dot-containing composition. By forming the surface coating layer, compatibility with the polymerizable polymer composition is improved, and a quantum dot-containing composition in which the quantum dots are uniformly dispersed without aggregation can be produced.

[0055] In the present invention, the purification method is not particularly limited, but for example, the product can be purified by adding ethanol to precipitate the reaction solution, centrifuging the precipitate, and removing the supernatant.

[0056] In the present invention, the method for measuring the content of free thiol groups in the surface coating layer is not particularly limited. For example, 1 g of DTNB (5,5'-Dithiobis(2-nitrobenzoic acid) is dissolved in 100 mL of EtOH, and the solid concentration is calculated from the weight change before and after the solvent removal of the quantum dot toluene solution. 1 mL of DTNB solution is added to 5 mL of the quantum dot toluene solution and left for 1 hour. The absorbance at 412 nm is measured with an ultraviolet-visible absorption spectrometer, and the molar absorbance (ε = 1.55 × 10) of the generated 2-Nitro-5-mercaptobenzoic acid is measured. 4 ) the content of free thiol groups can be measured.

[0057] (Wavelength conversion material) The wavelength conversion member of the present invention is a cured product obtained by curing the quantum dot-containing composition. The form of the wavelength conversion member in the present invention is not particularly limited, but examples thereof include a wavelength conversion film in which the quantum dot-containing composition is dispersed in a resin by processing into a sheet and then curing, and a wavelength conversion color filter patterned as an inkjet or resist material. The method for producing the wavelength conversion member is not particularly limited, but for example, the quantum dot-containing composition can be applied to a transparent film or substrate material such as PET or polyimide, cured, and laminated to obtain a wavelength conversion member.

[0058] To apply the material to transparent film, spraying methods such as spray or inkjet, spin coating or bar coater can be used.

[0059] The quantum dot-containing composition can be cured, for example, by heating a film coated with the quantum dot-containing composition at 60° C. for 2 hours and then at 150° C. for 4 hours. The quantum dot-containing composition may also be cured using a photopolymerization reaction, for example, by using a UV LED irradiation device with a wavelength of 365 nm and an output of 4000 mW / cm. 2 The composition can be cured by irradiating the composition with light for 20 seconds. Although not particularly limited, the composition can be appropriately changed depending on the application.

[0060] By introducing into such a surface coating layer a substituent that polymerizes with the polymerizable polymer in the polymerizable polymer composition, it becomes possible to produce a wavelength conversion member that has high reliability after curing and is free from aggregation and curing inhibition. EXAMPLES

[0061] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these. In these examples, InP / ZnSe / ZnS core-shell quantum dots were used as the quantum dot material.

[0062] [Example 1] (Quantum dot core synthesis process) 0.23g (0.9mmol) of palmitic acid, 0.088g (0.3mmol) of indium acetate, and 10mL of 1-octadecene were added to the flask, and the mixture was heated and stirred at 100℃ under reduced pressure to dissolve the raw materials and degassed for 1 hour. After that, nitrogen was purged into the flask, and 0.75mL (0.15mmol) of a 0.2M solution of tristrimethylsilylphosphine and trioctylphosphine was added, and the temperature was raised to 300℃. The solution turned from yellow to red, and it was confirmed that core particles were formed.

[0063] (Quantum dot shell layer synthesis process) Next, 2.85g (4.5mmol) of zinc stearate and 15mL of 1-octadecene were added to another flask, and the mixture was heated and stirred at 100°C under reduced pressure. While dissolving, the mixture was degassed for 1 hour to prepare a 0.3M zinc stearate octadecene solution. 3.0mL (0.9mmol) was added to the reaction solution after the core synthesis and cooled to 200°C. Next, 0.474g (6.0mmol) of selenium and 4mL of trioctylphosphine were added to another flask, and the mixture was heated to 150°C and dissolved to prepare a 1.5M selenium trioctylphosphine solution. The reaction solution after the core synthesis step, which had been cooled to 200°C, was heated to 320°C over 30 minutes, and the selenium trioctylphosphine solution was added in 0.1mL increments to a total of 0.6mL (0.9mmol), and the mixture was held at 320°C for 10 minutes and then cooled to room temperature. 0.44 g (2.2 mmol) of zinc acetate was added and dissolved by heating and stirring at 100°C under reduced pressure. The flask was purged again with nitrogen and heated to 230°C, and 0.98 mL (4.0 mmol) of 1-dodecanethiol was added and held for 1 hour. The resulting solution was cooled to room temperature to produce a solution containing core-shell quantum dots.

[0064] (ligand exchange process) (3-mercaptopropyl)triethoxysilane (Tokyo Chemical Industry Co., Ltd.) was used as a ligand having a substituent that forms a siloxane bond and a substituent that coordinates to the quantum dot surface. For the ligand exchange reaction, (3-mercaptopropyl)triethoxysilane (3.0 mmol) was added to the solution after the shell synthesis process that had been cooled to room temperature, and the solution was stirred for 24 hours. After the reaction was completed, ethanol was added to precipitate the reaction solution, which was then centrifuged and the supernatant was removed. The same purification was carried out once more, and the solution was dispersed in toluene to produce a quantum dot solution coordinated with a ligand having a substituent that forms a siloxane bond.

[0065] (Surface coating layer formation process and purification process) Triethoxyvinylsilane (4.0 mmol), diphenylsilanediol (6.0 mmol), barium hydroxide monohydrate (0.15 mmol), and the quantum dot toluene solution after the ligand exchange process were added to a flask that had been purged with nitrogen, and the mixture was heated and stirred at 65°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and ethanol was added to precipitate the reaction solution, which was then centrifuged to remove the supernatant and dispersed in toluene for purification.

[0066] (Free thiol titration) 1 g of DTNB (5,5'-Dithiobis(2-nitrobenzoic acid) was dissolved in 100 mL of EtOH. Next, the solid concentration was calculated from the weight change before and after the solvent removal of the quantum dot toluene solution, and 1 mL of DTNB solution was added to 5 mL of the quantum dot toluene solution and left for 1 hour. After that, the absorbance at 412 nm was measured with an ultraviolet-visible absorption spectrometer (JASCO V-750) and the molar absorbance (ε = 1.55 × 10) of the generated 2-Nitro-5-mercaptobenzoic acid was calculated. 4 The amount of free thiol groups (SH amount) was measured from the molar mass of the free thiol groups and the solid concentration of the quantum dots described above. The amount of free SH contained in the quantum dots was calculated to be 1.01 mmol per 1 g of quantum dots.

[0067] (Polymerizable polymer composition mixing step) The solution after the surface coating layer formation process dispersed in toluene and methacrylic modified silicone oil X-32-3817-3 (Shin-Etsu Chemical Co., Ltd.) were weighed and mixed so that the quantum dots were contained at 20 mass% in terms of non-volatile component ratio. After mixing, the solvent was removed by an evaporator to obtain a quantum dot-containing composition.

[0068] (Manufacturing process of wavelength conversion material) The quantum dot-containing composition thus obtained was used to produce a wavelength conversion member. The quantum dot-containing composition was degassed using a stirring degassing machine, poured onto a PET film, and formed into a thin film using a bar coater. The formed thin film was then irradiated with a UV LED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm.2 The quantum dot-containing layer was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member having a thickness of 50 μm.

[0069] (Emission wavelength, fluorescence emission half-width, fluorescence emission efficiency measurement) In the examples and comparative examples, the fluorescence emission characteristics of the quantum dots were evaluated using a quantum efficiency measurement system (QE-2100) manufactured by Otsuka Electronics Co., Ltd., and the emission wavelength, fluorescence emission half-width, and fluorescence emission efficiency (internal quantum efficiency) of the quantum dots at an excitation wavelength of 450 nm were measured.

[0070] (Reliability test) The obtained wavelength conversion member was treated at 85° C. and 85% RH (relative humidity) for 250 hours, and the fluorescence emission efficiency of the wavelength conversion member after the treatment was measured to evaluate its reliability.

[0071] [Comparative Example 1] The quantum dot shell layer synthesis process was carried out in the same manner as in Example 1, and the surface coating layer formation process was carried out without carrying out the process of adding ethanol after ligand exchange to remove excess ligands in the ligand exchange process and precipitating the quantum dots to purify them. The amount of free SH was measured in the same manner as in Example 1, and was 8 mmol per 1 g of quantum dots. The rest was produced in the same manner as in Example 1. Viscosity increased during the manufacturing process of the wavelength conversion member, air bubbles could not be removed, and a uniform film could not be formed.

[0072] [Comparative Example 2] The quantum dot shell layer was prepared in the same manner as in Example 1 up to the synthesis step.

[0073] (ligand exchange process) (3-Dimethylaminopropyl)triethoxysilane (Tokyo Chemical Industry Co., Ltd.) was used as a ligand having a substituent that forms a siloxane bond and a substituent that coordinates to the quantum dot surface. For the ligand exchange reaction, (3-dimethylaminopropyl)triethoxysilane (3.0 mmol) was added to the solution after the shell synthesis process that had been cooled to room temperature, and the solution was stirred for 24 hours. After the reaction was completed, the same preparation as in Comparative Example 1 was performed. The amount of free SH was measured after the surface coating layer formation process in the same manner as in Example 1, and was 6 mmol per 1 g of quantum dots. The rest of the preparation was performed in the same manner as in Example 1. Viscosity increased during the manufacturing process of the wavelength conversion member, air bubbles could not be removed, and a uniform film could not be formed.

[0074] [Example 2] The surface coating layer forming step and the purification step were carried out in the same manner as in Example 1.

[0075] (Polymerizable polymer composition mixing step) The solution after the surface coating layer formation process dispersed in toluene and acrylic resin RA-4101 (Negami Sangyo Co., Ltd.) were weighed so that the quantum dots were contained at 20% by mass in terms of non-volatile component ratio, and 5 parts by mass of photoradical generator Irgacure 1173 was added to 100 parts by mass of the acrylic resin non-volatile component and mixed. After mixing, the toluene solvent was removed by distillation under reduced pressure to obtain a quantum dot-containing composition.

[0076] (Method of manufacturing wavelength conversion member) The obtained quantum dot-containing composition was used to produce a wavelength conversion member. The quantum dot-containing composition was vacuum degassed, and the quantum dot-containing composition with a solid content of 20% was poured into a fluororesin-coated mold with a size of 20 cm x 10 cm square and a thickness of 500 μm, and heated on a hot plate at 120°C for 1 hour to evaporate the solvent and produce a quantum dot-containing layer. A part of the layer was cut out and developed with a PGMEA solution to confirm that there was no remaining film. The remaining quantum dot-containing layer was then irradiated with a UVLED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The film was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member of 100 μm.

[0077] [Comparative Example 3] The surface coating layer forming process and the purification process were carried out in the same manner as in Comparative Example 1, and the remaining processes were carried out in the same manner as in Example 2. Since a residual film remained after development with the PGMEA solution, it was confirmed that a dark reaction was proceeding. After that, the remaining quantum dot-containing layer was irradiated with a UV LED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The film was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member of 100 μm.

[0078] [Example 3] The preparation was carried out in the same manner as in Example 1 up to the ligand exchange step.

[0079] (Surface coating layer formation process and purification process) Triethoxysilylpropyl methacrylate (4.0 mmol), diphenylsilanediol (6.0 mmol), barium hydroxide monohydrate (0.15 mmol), and the quantum dot toluene solution after the ligand exchange process were added to a flask that had been purged with nitrogen, and the mixture was heated and stirred at 65°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, ethanol was added to precipitate the reaction solution, and the mixture was centrifuged to remove the supernatant. The mixture was dispersed in toluene and added to a flask that had been purged with nitrogen in advance, and 2 parts by mass of isocyanuric acid derivative DA-MGIC (Shikoku Kasei Corporation) was added per 100 parts by mass of the quantum dot toluene solution. Furthermore, 1 part by mass of Irgacure 1173 was added per 100 parts by mass of DA-MGIC, and after stirring and mixing, the mixture was irradiated with a UV LED irradiation device at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The reaction mixture was irradiated with light for 20 seconds. After the reaction was completed, ethanol was added to cause precipitation, and the mixture was centrifuged to remove the supernatant and then dispersed in toluene again for purification. The amount of free SH was measured in the same manner as in Example 1 and found to be 0.3 mmol per 1 g of quantum dots.

[0080] (Polymerizable polymer composition mixing step) The solution after the surface coating layer formation process in which the epoxy-containing silicone resin (manufactured by Shin-Etsu Chemical, CAS No. 2253674-54-1) was dispersed in toluene was weighed and mixed so that the quantum dots were contained at 20% by mass in terms of non-volatile component ratio. 2 parts by mass of photoacid generator CPI-310FG (manufactured by San-Apro) and 20 parts by mass of crosslinker THI-DE were weighed and mixed with respect to 100 parts by mass of silicone resin non-volatile component. After mixing, the toluene solvent was removed by distillation under reduced pressure to obtain a quantum dot-containing composition.

[0081] (Method of manufacturing wavelength conversion member) The obtained quantum dot-containing composition was used to produce a wavelength conversion member. The quantum dot-containing composition was vacuum degassed, and the quantum dot-containing composition with a solid content of 20% was poured into a fluororesin-coated mold with a size of 20 cm x 10 cm square and a thickness of 500 μm, and heated on a hot plate at 120°C for 1 hour to evaporate the solvent and produce a quantum dot-containing layer. A part of the layer was cut out and developed with a PGMEA solution to confirm that there was no remaining film. The remaining quantum dot-containing layer was then irradiated with a UVLED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The film was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member of 100 μm.

[0082] [Example 4] The preparation was carried out in the same manner as in Example 1 up to the ligand exchange step.

[0083] (Surface coating layer formation process and purification process) Triethoxysilylpropyl methacrylate (4.0 mmol), diphenylsilanediol (6.0 mmol), barium hydroxide monohydrate (0.15 mmol), and the quantum dot toluene solution after the ligand exchange process were added to a flask purged with nitrogen, and the mixture was heated and stirred at 65°C for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, ethanol was added to precipitate the reaction solution, and the mixture was centrifuged and the supernatant was removed. The mixture was dispersed in toluene and added to a flask purged with nitrogen in advance, and 2 parts by mass of a phenol-reactive compound having a fluorene skeleton, BIOAP-FL (Asahi Organic Chemicals Industry), was added per 100 parts by mass of the quantum dot toluene solution. Furthermore, 1 part by mass of Irgacure1173 was added per 100 parts by mass of BIOAP-FL, and after stirring and mixing, the mixture was irradiated with a UVLED irradiation device at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The reaction mixture was irradiated with light for 20 seconds. After the reaction was completed, ethanol was added to cause precipitation, and the mixture was centrifuged to remove the supernatant and then dispersed in toluene again for purification. The amount of free SH was measured in the same manner as in Example 1 and found to be 0.2 mmol per 1 g of quantum dots.

[0084] (Polymerizable polymer composition mixing step) Phenol-crosslinkable silicone resin (CAS No. 916059-41-1, manufactured by Shin-Etsu Chemical Co., Ltd.) and the solution after the surface coating layer formation process, dispersed in toluene, were weighed and mixed so that the quantum dots were contained at 20% by mass in terms of non-volatile component ratio. 2 parts by mass of photoacid generator CPI-310FG (manufactured by San-Apro Co., Ltd.) and 20 parts by mass of crosslinker THI-DE were weighed and mixed with respect to 100 parts by mass of silicone resin non-volatile component. After mixing, the toluene solvent was removed by distillation under reduced pressure to obtain a quantum dot-containing composition.

[0085] (Method of manufacturing wavelength conversion member) The obtained quantum dot-containing composition was used to produce a wavelength conversion member. The quantum dot-containing composition was vacuum degassed, and the quantum dot-containing composition with a solid content of 20% was poured into a fluororesin-coated mold with a size of 20 cm x 10 cm square and a thickness of 500 μm, and heated on a hot plate at 120°C for 1 hour to evaporate the solvent and produce a quantum dot-containing layer. A part of the layer was cut out and developed with a PGMEA solution to confirm that there was no remaining film. The remaining quantum dot-containing layer was then irradiated with a UVLED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The film was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member of 100 μm.

[0086] [Example 5] The steps up to the ligand exchange step were performed in the same manner as in Comparative Example 1, and then the steps up to the polymerizable polymer composition mixing step were performed in the same manner as in Example 4. The amount of free SH was measured in the same manner as in Example 1 and was found to be 3.5 mmol per 1 g of quantum dots.

[0087] (Method of manufacturing wavelength conversion member) The obtained quantum dot-containing composition was used to produce a wavelength conversion member. The quantum dot-containing composition was vacuum degassed, and the quantum dot-containing composition with a solid content of 20% was poured into a fluororesin-coated mold with a size of 20 cm x 10 cm square and a thickness of 500 μm, and heated on a hot plate at 120°C for 1 hour to evaporate the solvent and produce a quantum dot-containing layer. A part of the layer was cut out and developed with a PGMEA solution to confirm that there was no remaining film. The remaining quantum dot-containing layer was then irradiated with a UVLED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 When the resin was photocured by irradiating it with light for 20 seconds to produce a wavelength conversion material with a thickness of 100 μm, some residual liquid was found, indicating that curing was being inhibited. The residual liquid was wiped off with a rag to produce a wavelength conversion material.

[0088] [Comparative Example 4] The surface coating layer was formed in the same manner as in Comparative Example 1, and then the polymerizable polymer composition mixing step was carried out in the same manner as in Example 4. The amount of free SH was measured in the same manner as in Example 1 and was found to be 4.2 mmol per 1 g of quantum dots.

[0089] (Method of manufacturing wavelength conversion member) The obtained quantum dot-containing composition was used to produce a wavelength conversion member. The quantum dot-containing composition was vacuum degassed, and the quantum dot-containing composition with a solid content of 20% was poured into a fluororesin-coated mold with a size of 20 cm x 10 cm square and a thickness of 500 μm, and heated on a hot plate at 120°C for 1 hour to evaporate the solvent and produce a quantum dot-containing layer. A portion was cut out and developed with a PGMEA solution to confirm the remaining film, and it was confirmed that the dark reaction was proceeding. Thereafter, the remaining quantum dot-containing layer was irradiated with a UVLED irradiation device in a nitrogen atmosphere at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The film was photocured by irradiating it with light for 20 seconds to prepare a wavelength conversion member of 100 μm.

[0090] Table 1 shows the results of comparing Examples 1 to 5 with Comparative Examples 1 to 4. [Table 1]

[0091] The internal quantum efficiency after the quantum dot-containing composition is cured (wavelength conversion member), the rate of decrease in the internal quantum efficiency after the reliability evaluation, the presence or absence of thickening or residual film, and the presence or absence of photocuring failure are shown. From the results in Table 1, it can be seen that the internal quantum efficiency of the comparative example is lower than that of the examples, and the emission wavelength also has a large shift to a long wavelength. On the other hand, when comparing the results of the reliability test (85°C, 85% RH, 250 hours treatment), the comparative example is more deteriorated than the examples, but the stability is relatively good due to the formation of a surface coating layer. Regarding the thickening of the quantum dot-containing composition, when comparing Example 1 with Comparative Examples 1 and 2, it was found that the comparative example was more thickened, and as a result, air bubbles remained after photocuring, and the film quality was deteriorated. In the other comparative examples, thickening was not observed, probably because PGMEA, an organic solvent, was included. On the other hand, when comparing Examples 2 to 5 and Comparative Examples 3 to 4 for the presence or absence of residual film and photocuring failure after PGMEA treatment, none of the examples had any residual film, and no phenomenon such as thickening occurred. In addition, there were no curing defects except for Example 5, and a quantum dot-containing layer was formed, whereas in Comparative Examples 3 and 4, a residual film was generated after PGMEA treatment, indicating that a dark reaction with the remaining thiol groups was progressing.

[0092] As described above, it has been confirmed that the quantum dot-containing composition of the present invention exhibits high stability and has good film quality after curing, and can be applied to quantum dot-containing resists and quantum dot-containing inkjet inks.

[0093] The present specification includes the following aspects. [1]: A quantum dot-containing composition containing quantum dots that emit fluorescence when exposed to excitation light, the quantum dot-containing composition being a mixture of the quantum dots and a polymerizable polymer composition, the surfaces of the quantum dots containing a surface coating layer having a siloxane bond, and the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots. [2]: The quantum dot-containing composition according to [1] above, characterized in that the content of the free thiol groups contained in the surface coating layer is 3.0 mmol or less per 1 g of the quantum dots. [3]: The quantum dot-containing composition according to [2] above, characterized in that the content of the free thiol groups contained in the surface coating layer is 1.0 mmol or less per 1 g of the quantum dots. [4]: The quantum dot-containing composition according to any one of [1] to [3] above, characterized in that the surface coating layer has one or more reactive substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group. [5]: The quantum dot-containing composition according to any one of [1] to [4] above, characterized in that the polymerizable polymer contained in the polymerizable polymer composition has one or more polymerizable substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group. [6]: A wavelength conversion member, which is a cured product of the quantum dot-containing composition according to any one of [1] to [5] above. [7]: A method for producing any one of the quantum dot-containing compositions according to [1] to [5] above, which contains quantum dots that emit fluorescence when exposed to excitation light, a ligand exchange step of mixing a solution in which the quantum dots are dispersed with a ligand having a substituent that forms a siloxane bond, and coordinating the ligand to the outermost surface of the quantum dots; a surface coating layer forming step of forming a surface coating layer by reacting the substituent that forms a siloxane bond with a compound that reacts with the substituent that forms a siloxane bond to generate a polysiloxane, after the ligand exchange step; a purification step of purifying the surface coating layer so that the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots by purification after the surface coating layer formation step; A method for producing a quantum dot-containing composition, comprising: a polymerizable polymer composition mixing step of mixing the quantum dots coated with the surface coating layer with the polymerizable polymer composition after the purification step.

[0094] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A quantum dot-containing composition containing quantum dots that emit fluorescence in response to excitation light, the quantum dot-containing composition being a mixture of the quantum dots and a polymerizable polymer composition, the surfaces of the quantum dots containing a surface coating layer having a siloxane bond, and the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots.

2. 2. The quantum dot-containing composition according to claim 1, wherein the content of the free thiol groups contained in the surface coating layer is 3.0 mmol or less per 1 g of the quantum dots.

3. 3. The quantum dot-containing composition according to claim 2, wherein the content of the free thiol groups contained in the surface coating layer is 1.0 mmol or less per 1 g of the quantum dots.

4. The quantum dot-containing composition according to claim 1, characterized in that the surface coating layer has one or more reactive substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group.

5. The polymerizable polymer contained in the polymerizable polymer composition has one or more polymerizable substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group. The quantum dot-containing composition according to claim 1, characterized in that the polymerizable polymer contained in the polymerizable polymer composition has one or more polymerizable substituents selected from a vinyl group, an acrylic group, a methacrylic group, a hydroxyl group, a phenolic hydroxyl group, and an epoxy group.

6. A wavelength conversion member comprising a cured product of the quantum dot-containing composition according to claim 1 .

7. A method for producing a quantum dot-containing composition according to any one of claims 1 to 5, which contains quantum dots that emit fluorescence when exposed to excitation light, a ligand exchange step of mixing a solution in which the quantum dots are dispersed with a ligand having a substituent that forms a siloxane bond, and coordinating the ligand to the outermost surface of the quantum dots; a surface coating layer forming step of forming a surface coating layer by reacting the substituent that forms a siloxane bond with a compound that reacts with the substituent that forms a siloxane bond to generate a polysiloxane, after the ligand exchange step; a purification step of purifying the surface coating layer so that the content of free thiol groups contained in the surface coating layer is 4.0 mmol or less per 1 g of the quantum dots by purification after the surface coating layer formation step; A method for producing a quantum dot-containing composition, comprising: a polymerizable polymer composition mixing step of mixing the quantum dots coated with the surface coating layer with the polymerizable polymer composition after the purification step.