Quantum dot body, quantum dot composition, wavelength conversion material, and methods for producing same

Abstract

To provide a quantum dot body capable of maintaining high emission efficiency while improving its dispersibility in solvents having high polarity.SOLUTION: A quantum dot body 1 including a quantum dot 4 that emits fluorescence upon excitation light, comprises a core 2 of a semiconductor nanoparticle and a shell 3 of the semiconductor nanoparticle covering the core, and the surface of the quantum dot is modified with a compound 5 having a methacryloyloxyethyl group and a hydrophilic group, represented by formula (I), where R1 represents a hydrophilic group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a quantum dot body, a quantum dot composition, a wavelength converting material, and methods for producing the same. [Background technology]

[0002] Quantum dots, which are semiconductor particles with nanometer-sized particle diameters, have discrete energy levels due to the excitons generated by light absorption being confined in nanometer-sized spaces, and their band gaps depend on the particle diameter. As a result, quantum dots have highly efficient fluorescence emission and sharp emission spectra. Furthermore, because the band gap changes depending on the particle diameter, quantum dots have the advantage of being able to control the emission wavelength, and are expected to be used as wavelength conversion materials in solid-state lighting and displays (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-022028 [Patent Document 2] International Publication No. 2011 / 081037 [Patent Document 3] Special Publication No. 2010-523557 Summary of the Invention [Problem to be solved by the invention]

[0004] Quantum dots containing Cd and Pb are known to exhibit excellent fluorescence properties. However, because Cd and Pb are highly toxic to the human body and the environment, restrictions on their use are being considered around the world, including the European Union's RoHS Directive. Therefore, quantum dots that do not contain these toxic elements are being investigated.

[0005] Furthermore, quantum dots are prone to instability due to their small nanometer-sized particle diameter, large specific surface area, high surface energy, and surface activity. This makes them susceptible to surface defects due to dangling bonds and oxidation reactions on the quantum dot surface, which can cause deterioration of their fluorescence emission properties. Currently available quantum dots have these stability issues, and are known to experience deterioration of their emission properties due to heat, humidity, photoexcitation, and other factors.

[0006] To prevent this degradation, organic or inorganic ligands called ligands are attached to the quantum dot surface after synthesis. The ligands passivate the defects, suppressing the degradation of the fluorescence emission efficiency.

[0007] Furthermore, the application of quantum dots as wavelength conversion materials to color filters used in displays and other devices has been proposed as a packaging method. When applying quantum dots to color filters, it is important to create a quantum dot surface condition suitable for the patterning method. Currently, color filters are primarily produced using a photolithography method in which a pigment-containing photosensitive resin composition is applied to a glass substrate, the solvent is dried, and the substrate is exposed to UV light through a mask. The uncured portions are then removed by alkaline development to form color patterns. This process is repeated to form blue, red, and green patterns. This photolithography method has many problems, including significant raw material waste due to the uncured portions being wasted, and the process is complicated and requires expensive equipment.

[0008] For this reason, inkjet methods have been investigated in recent years. Inkjet methods are cost-competitive, as they eliminate raw material waste and allow for larger sizes and larger areas to be produced without the need for expensive equipment. However, the technology to create fine nozzles is difficult, and as nozzles become smaller, problems arise such as clogging and unstable discharge. Therefore, both photolithography, which has a proven track record in miniaturization, and inkjet methods, which are cost-competitive, are being investigated.

[0009] The challenge with both photolithography and inkjet printing is to create a resin composition containing quantum dots at a high concentration and with high dispersion. With the exception of a few resin compositions, quantum dots are dispersed in polar solvents such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME). However, quantum dots are essentially hydrophobic and difficult to disperse in these solvents and resin materials, resulting in aggregation, making it difficult to create a photosensitive resin composition containing quantum dots at a high concentration and with high dispersion.

[0010] Various studies have been conducted to date to disperse quantum dots in polar solvents. For example, in Patent Document 2, a composite in which semiconductor nanoparticles are dispersed in silica glass is produced by reacting metal alkoxides stepwise on the surface of semiconductor nanoparticles to deposit a silica glass layer, making it possible to disperse the composite in water. However, the composite obtained by this production method has a problem in that the luminescence efficiency of the quantum dots is significantly reduced.

[0011] Furthermore, in Patent Document 3, it is possible to impart water solubility by producing a composite in which quantum dots are encapsulated in an amphiphilic polymer. However, in this composite, the polymer accounts for a large proportion of the weight and volume of the entire composite. Therefore, when quantum dots are filled and dispersed in a resin with a limited volume, such as for use in a color filter, the total amount of quantum dots is reduced, making it difficult to obtain sufficient light-emitting properties.

[0012] Another method is to improve dispersibility in polar solvents by using ligands with high affinity for polar solvents and adsorbing the ligands onto the quantum dot surface. However, these ligands on the quantum dot surface are released as soon as the solvent is removed. Therefore, when quantum dots are used as wavelength conversion materials for displays, removing the solvent to mix the quantum dots with a resin material can lead to problems such as aggregation of the quantum dots in the resin, a deterioration in the initial luminescence efficiency, and a deterioration over time in the luminescence efficiency of the composition consisting of quantum dots and a resin material.

[0013] The present invention has been made to solve the above problems, and aims to provide a quantum dot body that can maintain high luminous efficiency and has improved dispersibility in highly polar solvents. It is also an object of the present invention to provide a quantum dot composition in which the quantum dot body is dispersed in a resin material, and a wavelength converting material containing a cured product of the quantum dot composition, in which the initial value of luminous efficiency and deterioration over time are suppressed, as well as methods for producing the same. [Means for solving the problem]

[0014] The present invention has been made to achieve the above-mentioned object, and provides a quantum dot body containing quantum dots that emit fluorescence when exposed to excitation light, the quantum dots including a semiconductor nanoparticle core and a semiconductor nanoparticle shell that covers the semiconductor nanoparticle core, and the surface of the quantum dots is modified with a compound having a methacryloyloxyethyl group and a hydrophilic group, as shown in the following formula (I):

[0015] [ka] (R1 represents a hydrophilic group.)

[0016] Such quantum dot bodies can maintain high luminous efficiency and have improved dispersibility in highly polar solvents.

[0017] In this case, the hydrophilic group may be selected from quaternary ammonium salts, carboxylates, succinates, isocyanates, maleates, hydrogen phosphates, 1,2,4-benzenetricarboxylates, salts of trimellitic anhydride, phthalates, acetoacetates, and thiocates.

[0018] This improves the affinity to polar solvents, and improves the dispersibility of the quantum dot bodies in polar solvents.

[0019] In this case, the compound may be bis[2-(methacryloyloxy)ethyl]phosphate, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, mono-2-(methacryloyloxy)ethyl succinate, mono[2-(methacryloyloxy)ethyl]maleate, 2-(methacryloyloxy)ethyl isocyanate, (2-methacryloyloxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, 4-MET (4-methacryloxyethyltrimellitic acid), 4-META (4-methacryloxyethyl trimellitic anhydride), mono-2-(methacryloyloxy)ethyl phthalate, bis[2-(methacryloyloxy)ethyl](methyl)ammonio]propane-1-sulfonic acid, 2-(methacryloyloxy)ethyl acetoacetate, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 4-[[2-(methacryloyloxy)ethyl]dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 2-methacryloyloxyethyl thioctic acid, and [2-(methacryloyloxy)ethyl]trimethylammonium methylsulfate.

[0020] This further improves the affinity to polar solvents, and the dispersibility of the quantum dot bodies in polar solvents is further improved.

[0021] In this case, the compound may be contained in an amount of 0.1 to 50% by mass relative to the quantum dots.

[0022] This effectively prevents the quantum dots from aggregating together, allowing the effects of modifying the quantum dot surfaces to be fully and stably exerted.

[0023] In this case, the compound may be contained in an amount of 0.5 to 30% by mass relative to the quantum dots.

[0024] This makes it possible to more effectively suppress the aggregation of quantum dots, and to more sufficiently and stably exert the effect of modifying the quantum dot surface.

[0025] In this case, the quantum dot composition can be prepared by dispersing the quantum dot bodies in a resin material.

[0026] Such a quantum dot composition has improved dispersibility of the quantum dot bodies in the resin material.

[0027] In this case, the wavelength converting material may contain a cured product of the quantum dot composition.

[0028] In such a wavelength conversion material, the quantum dots are dispersed in the resin material at a high concentration without agglomerates while maintaining high luminous efficiency, and reliability is improved.

[0029] In this case, the method for producing the quantum dot body can include a quantum dot production step of producing quantum dots each including a semiconductor nanoparticle core and a semiconductor nanoparticle shell covering the semiconductor nanoparticle core, and a quantum dot modification step of modifying the surface of the quantum dot with a compound having a methacryloyloxyethyl group and a hydrophilic group represented by formula (I).

[0030] This makes it possible to produce quantum dot bodies that can maintain high luminous efficiency and have improved dispersibility in highly polar solvents.

[0031] In this case, the quantum dot composition can be produced by dispersing the quantum dot bodies produced by the quantum dot body production method in a resin material.

[0032] This makes it possible to produce a quantum dot composition in which the dispersibility of the quantum dot bodies in the resin material is improved.

[0033] In this case, the method for producing a wavelength converting material can be a method for producing a wavelength converting material by curing the quantum dot composition produced by the method for producing a quantum dot composition.

[0034] As a result, even after curing the quantum dot composition, it is possible to disperse the quantum dots in the resin material without forming aggregates while maintaining high luminous efficiency, and it is possible to produce a wavelength converting material with improved reliability. [Effects of the Invention]

[0035] As described above, the quantum dot body of the present invention can maintain high luminous efficiency and improve dispersibility in highly polar solvents. Furthermore, by using the quantum dot body of the present invention to form a quantum dot composition and a wavelength converting material, the initial value of the luminous efficiency and deterioration over time can be suppressed. Furthermore, it is possible to provide methods for producing a quantum dot body, a quantum dot composition, and a wavelength converting material having the above effects. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a schematic cross-sectional view showing an example of a quantum dot body of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be described in detail below, but the present invention is not limited thereto.

[0038] As described above, there has been a demand for quantum dots that can maintain high luminous efficiency and have improved dispersibility in highly polar solvents.

[0039] As a result of extensive research into the above-mentioned problems, the present inventors have found that a quantum dot body containing quantum dots that emit fluorescence when exposed to excitation light, wherein the quantum dots comprise a semiconductor nanoparticle core and a semiconductor nanoparticle shell that covers the semiconductor nanoparticle core, and the surface of the quantum dots is modified with a compound having a methacryloyloxyethyl group and a hydrophilic group, as shown in the following formula (I), can maintain high luminous efficiency and has improved dispersibility in highly polar solvents, thereby completing the present invention.

[0040] [ka] (R1 represents a hydrophilic group.)

[0041] Furthermore, it was found that a quantum dot composition in which the quantum dot bodies are dispersed in a resin material, and a wavelength converting material obtained by curing the quantum dot composition, have a high initial luminous efficiency and exhibit reduced deterioration in luminous efficiency over time. As a result, it was found that a wavelength converting material containing a cured product of a quantum dot composition in which the quantum dot bodies are dispersed in a resin material can suppress the decrease in internal quantum yield during 100 hours of treatment to within 10% in a reliability test at 85°C and 85% RH without a barrier film, thereby enabling improved stability.

[0042] That is, the present invention relates to a quantum dot body 1 including quantum dots 4 that emit fluorescence in response to excitation light, as shown in FIG. 1, wherein the quantum dots 4 include a semiconductor nanoparticle core 2 and a semiconductor nanoparticle shell 3 that covers the semiconductor nanoparticle core 2, and the surface of the quantum dots 4 is modified with a compound 5 having a methacryloyloxyethyl group and a hydrophilic group, as shown in formula (I) above; a quantum dot composition in which the quantum dot bodies 1 are dispersed in a resin material; and a wavelength conversion material including a cured product of the quantum dot composition, as well as methods for producing the same.

[0043] (Quantum dots) The structure of the quantum dots according to the present invention is not particularly limited as long as they include a semiconductor nanoparticle core and a semiconductor nanoparticle shell. Such quantum dots have excellent fluorescence emission properties and stability. For example, in semiconductor nanoparticles with a core / shell structure, in which a nano-sized semiconductor particle serves as the core and a semiconductor particle with a larger band gap and lower lattice mismatch than the core serves as the shell, excitons generated in the shell are confined inside the core particle, thereby improving fluorescence emission efficiency, and further improving stability because the core surface is covered by the shell.

[0044] The quantum dots may also include a semiconductor nanoparticle core and a plurality of semiconductor nanoparticle shells covering the semiconductor nanoparticle core. Such quantum dots further suppress the deterioration of fluorescence emission efficiency.

[0045] The material for the semiconductor nanoparticle core of the core / shell semiconductor nanoparticles is preferably one that does not contain the elements Cd or Pb from the viewpoint of toxicity, and for example, a material selected from the group consisting of II-VI compounds, III-V compounds, I-III-VI compounds, II-IV-V compounds, and alloys or mixed crystals thereof can be used.

[0046] Specifically, examples of the material for the semiconductor nanoparticle core include a single crystal, multiple crystals, or mixed crystals selected from ZnS, ZnSe, ZnTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AgGaS2, AgInS2, AgGaSe2, AgInSe2, CuGaS2, CuGaSe2, CuInS2, CuInSe2, ZnSiP2, and ZnGeP2. Of these materials, ZnSe, ZnTe, and InP are particularly preferred in terms of fluorescence emission properties and stability.

[0047] Furthermore, the surface of the core particle of the core / shell semiconductor nanoparticles is preferably passivated with an inorganic compound, which inactivates defects on the surface of the core particle, improves the fluorescence emission efficiency, and further suppresses the deterioration of the fluorescence emission efficiency over time.

[0048] The inorganic compound used for passivation is not particularly limited, but examples include metal halides, and from the viewpoint of improving fluorescence emission efficiency, at least one compound selected from GaCl3, GaI3, GaBr3, ZnCl2, ZnBr2, ZnI2, InCl3, InBr3, InI3, AgCl, AgBr, AgI, KCl, KBr, KI, NaCl, NaBr, NaI, MgCl2, MgBr2, MgI2, CaCl2, CaBr2, CaI2, MnCl2, MnBr2, MnI2, FeCl2, FeBr2, FeI2, CuCl2, CuBr2, CuI2, ZrCl4, ZrBr4, ZrI4, GeCl4, GeBr4, and GeI4 is particularly preferred.

[0049] The material for the semiconductor nanoparticle shell is preferably one that does not contain elements such as Cd or Pb from the viewpoint of toxicity, but also has a large band gap and low lattice mismatch with respect to the core material, and can be selected from the group consisting of alloys and mixed crystals of II-VI compounds and III-V compounds.

[0050] Specific shell materials include those selected from the group consisting of ZnS, ZnSe, ZnTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, and InSb, either singly or in combination, or as mixed crystals. Of these materials, ZnSe and ZnS are particularly preferred in terms of improved fluorescence emission efficiency and stability.

[0051] [Quantum dot body] In the present invention, the modifying agent necessary for dispersing quantum dots in a polar solvent is a compound having a methacryloyloxyethyl group and a hydrophilic group, and the quantum dot body in the present invention includes the quantum dot and a compound having a methacryloyloxyethyl group and a hydrophilic group that modifies the surface of the quantum dot.

[0052] In the present invention, "modification" refers to a state in which a compound having a methacryloyloxyethyl group and a hydrophilic group is "adhered" to at least the surface of the quantum dot. Adhesion to the surface by "modification" includes partial and full-surface adhesion, and refers to a state in which the compound is attached to at least a part of the surface.

[0053] The term "adhesion" in the above context may refer to physical adsorption or chemical bonding, and may broadly refer to, for example, covalent bonding, ionic bonding, or hydrogen bonding, or may be a combination of these. As an example, a quantum dot body containing a compound having a methacryloyloxyethyl group and a hydrophilic group that modifies quantum dots may be in a state in which at least some of the organic or inorganic ligands attached during quantum dot synthesis coexist, as long as it is dispersible in a polar solvent.

[0054] The structure of the compound having a methacryloyloxyethyl group and a hydrophilic group in the present invention is represented by the following formula (I).

[0055] [ka] (R1 represents a hydrophilic group.)

[0056] R1 in the formula (I) is not particularly limited as long as it is a hydrophilic group, and examples thereof include quaternary ammonium salts, carboxylates, succinates, isocyanates, maleates, hydrogen phosphates, 1,2,4-benzenetricarboxylates, salts of trimellitic anhydride, phthalates, acetoacetates, and thiocates.

[0057] The type of compound having a methacryloyloxyethyl group and a hydrophilic group represented by the formula (I) is not particularly limited, and examples thereof include bis[2-(methacryloyloxy)ethyl]phosphate, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, mono-2-(methacryloyloxy)ethyl succinate, mono[2-(methacryloyloxy)ethyl]maleate, 2-(methacryloyloxy)ethyl isocyanate, (2-methacryloyloxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, 4-MET (4-methacryloxyethyltrimellitic acid), 4-META (4-methacryloxyethyl trimellitic anhydride), mono-2-(methacryloyloxy)ethyl phthalate, bis[2-(methacryloyloxy)ethyl](methyl)ammonio]propane-1-sulfonic acid, 2-(methacryloyloxy)ethyl acetoacetate, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 4-[[2-(methacryloyloxy)ethyl]dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 2-methacryloyloxyethyl thioctic acid, and [2-(methacryloyloxy)ethyl]trimethylammonium methylsulfate.

[0058] These compounds have the structure shown in formula (I) above and contain hydrophilic groups. By modifying the surface of the quantum dots, their affinity to polar solvents is improved, and the dispersibility of the quantum dot bodies in polar solvents is improved.

[0059] The amount of the compound added as the surface modifier is not particularly limited, as long as it is within the range in which the compound having a methacryloyloxyethyl group and a hydrophilic group modifies the quantum dot surface. For example, an amount of 50% by mass (wt%) or less relative to the solid mass of the quantum dots is preferable because it effectively suppresses aggregation of the quantum dots, and an amount of 0.1% by mass (wt%) or more allows the effect of modification on the quantum dot surface to be sufficiently and stably exerted. Therefore, the amount of the surface modifier added is preferably in the range of 0.1 to 50% by mass (wt%), and more preferably in the range of 0.5 to 30% by mass (wt%), relative to the solid mass of the quantum dots.

[0060] [Quantum dot composition] The quantum dot bodies can also be used as a quantum dot composition in which they are dispersed in a resin material.

[0061] In the quantum dot composition of the present invention, the methacryloyl group moiety of the quantum dot body undergoes a crosslinking reaction with a polymer that is a base polymer of a resin material. The resin material may contain a polymerization initiator together with the polymer that is the base polymer, and may also contain other ingredients such as an organic solvent, a polymerizable crosslinking agent, a photoacid generator, an antioxidant, and a light scattering agent.

[0062] The polymer is selected from polymers derived from acrylic acid, methacrylic acid, acrylic esters, and methacrylic esters, copolymers combining multiple polymers, polymers having a skeletal structure with glycidyl (meth)acrylate repeating units, siloxane skeleton, urethane skeleton, silphenylene skeleton, norbornene skeleton, fluorene skeleton, and isocyanurate skeleton, depending on the application. Examples include acrylic resins, alkyd resins, melamine resins, epoxy resins, silicone resins, polyvinyl alcohol, polyvinylpyrrolidone, polyamides, polyamide-imides, polyimides, and other polyimide precursors and their esterification products, and reaction products of tetracarboxylic dianhydrides and diamines. These polymers also contain polymerizable substituents, which can be cured by combining them with a polymerization initiator. Examples of radically polymerizable substituents include vinyl groups, acrylic groups, methacrylic groups, and thiol groups, all of which are suitable for use. Examples of cationically polymerizable substituents include hydroxyl groups, phenolic hydroxyl groups, epoxy groups, glycidyl groups, oxetanyl groups, and isocyanate groups, all of which are suitable for use. In addition, a carboxy group may be introduced to impart alkaline developability.

[0063] The quantum dot composition of the present invention also preferably contains a polymerization initiator, as described above. The polymerization initiator may be a thermal or photopolymerization initiator, either of which may be suitably used depending on the base polymer. Examples of photoradical polymerization initiators include those in the Irgacure (registered trademark) series commercially available from BASF, such as Irgacure 290, Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure 819, and Irgacure 1173. Examples of the Darocure (registered trademark) series include TPO and Darocure 1173. Other known thermal radical polymerization initiators and photocationic polymerization initiators may also be included. The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the polymer to be added.

[0064] The quantum dot composition of the present invention may contain an organic solvent to improve its applicability. From the viewpoint of compatibility with quantum dots, organic solvents are preferred, such as ketones, alkylene glycol ethers, alcohols, and aromatic compounds. Ketones include acetone, methyl ethyl ketone, and cyclohexanone; alkylene glycol ethers include methyl cellosolve (ethylene glycol monomethyl ether), butyl cellosolve (ethylene glycol monobutyl ether), methyl cellosolve acetate, ethyl 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, and diethylene glycol methyl ether. Suitable solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, 3-methyl-3-methoxybutanol, and aromatic solvents such as benzene, toluene, and xylene. The quantum dot composition of the present invention may also contain a polymerizable crosslinker, a photoacid generator, an antioxidant, a light scattering agent, and the like, without any particular limitation, as long as the polymerizable coating properties are not affected.

[0065] In such a quantum dot composition, the methacryloyl group moiety of the compound having a methacryloyloxyethyl group and a hydrophilic group modifying the surface of the quantum dot undergoes a crosslinking reaction with a polymer that is the base polymer of the resin material, thereby suppressing the precipitation of aggregates of quantum dots in the resin, and thus improving dispersibility in the resin material.

[0066] [Wavelength conversion materials] The present invention also provides a wavelength converting material containing a cured product of the quantum dot composition. The wavelength converting material may be used as is or may be processed. One form of the wavelength converting material is a wavelength conversion film in which the quantum dot composition is dispersed in a resin and processed into a sheet and then cured.

[0067] In such a wavelength conversion material, the quantum dots are dispersed in the resin material at a high concentration without agglomerates while maintaining high luminous efficiency, and reliability is improved.

[0068] [Quantum dot manufacturing method] Next, a method for producing a quantum dot body of the present invention will be described. The method for producing a quantum dot body of the present invention includes a quantum dot production step of producing quantum dots each including a semiconductor nanoparticle core and a semiconductor nanoparticle shell covering the semiconductor nanoparticle core, and a quantum dot modification step of modifying the surface of the quantum dot with a compound having a methacryloyloxyethyl group and a hydrophilic group, as represented by the formula (I). This makes it possible to produce quantum dot bodies that can maintain high luminous efficiency and have improved dispersibility in highly polar solvents.

[0069] (Quantum dot manufacturing process) There are various methods for producing the core and shell of semiconductor nanoparticles, such as a liquid phase method or a gas phase method, but the present invention is not particularly limited to these. From the viewpoint of obtaining high fluorescence emission efficiency, it is preferable to use semiconductor nanoparticles obtained by a hot soap method or a hot injection method, in which precursor species are reacted at high temperature in a high-boiling-point nonpolar solvent.

[0070] (Quantum dot modification process) The method for modifying the quantum dot surface with a compound having a methacryloyloxyethyl group and a hydrophilic group is not particularly limited as long as the compound can be modified onto the quantum dot surface. One example is a method in which a two-phase system consisting of a polar solvent and a nonpolar solvent is used, and the nonpolar solvent in which quantum dots are dispersed and the polar solvent in which a compound having a methacryloyloxyethyl group and a hydrophilic group is dispersed are mixed by strong stirring or the like, and the quantum dot bodies, which are quantum dots modified with the compound having a methacryloyloxyethyl group and a hydrophilic group, are extracted into the polar solvent.

[0071] The type of non-polar solvent is not particularly limited as long as the quantum dots are dispersed without settling. The polar solvent is also not particularly limited as long as the compound having a methacryloyloxyethyl group and a hydrophilic group is dissolved without precipitating. Furthermore, the type of solvent is not limited as long as the polar solvent and the non-polar solvent are mixed and the resulting quantum dots are dispersed in the polar solvent, even if they are not separated into two phases.

[0072] The heating temperature when modifying the quantum dot surface with a compound having a methacryloyloxyethyl group and a hydrophilic group is not particularly limited, but for efficient modification, the heating temperature is preferably in the range of 30 to 100° C. Within this range, the quantum dot surface can be modified more efficiently.

[0073] [Method of manufacturing quantum dot composition] Next, we will explain a method for producing a quantum dot composition by dispersing the quantum dots produced by the above-mentioned quantum dot production method in a resin material. The resin material can be a polymer base polymer and a polymerization initiator, and may also contain organic solvents, polymerizable crosslinking agents, photoacid generators, antioxidants, light scattering agents, etc.

[0074] Suitable examples of the polymer include polymers derived from acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters, copolymers combining multiple polymers, and polymers having a skeletal structure with glycidyl (meth)acrylate as a repeating unit, a siloxane skeleton, a urethane skeleton, a silphenylene skeleton, a norbornene skeleton, a fluorene skeleton, and an isocyanurate skeleton. The polymer to be used may be selected appropriately depending on the application.

[0075] Furthermore, these polymers have polymerizable substituents introduced therein, and can be cured by using them in combination with a polymerization initiator. The polymerization initiator can be a thermal or photopolymerization initiator, and either can be suitably used depending on the base polymer. In addition, known thermal radical polymerization initiators and photocationic polymerization initiators may also be used.

[0076] The content of the polymerization initiator is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the polymer to be added. An organic solvent may be used to improve the coatability of the quantum dot composition. Furthermore, other agents such as a polymerizable crosslinker, a photoacid generator, an antioxidant, and a light scattering agent may also be used, with no particular limitations provided that they do not affect the coatability of the polymerizable agent.

[0077] According to such a method for producing a quantum dot composition, it is possible to produce a quantum dot composition with improved dispersibility of the quantum dot bodies in a resin material.

[0078] [Method of manufacturing wavelength converting material] The present invention also provides a method for producing a wavelength converting material by curing the quantum dot composition produced by the above-mentioned method for producing a quantum dot composition.

[0079] The method for producing the wavelength converting material is not particularly limited. For example, a resin composition in which a quantum dot composition is dispersed in a resin can be applied to a transparent film such as PET or polyimide, cured, and laminated to obtain the wavelength converting material.

[0080] The resin layer can be formed by coating onto the transparent film using a spraying method such as a spray or inkjet method, a spin coat method, a bar coater method, or a doctor blade method. The thickness of the resin layer and the transparent film is not particularly limited and can be selected appropriately depending on the application.

[0081] According to such a method for producing a wavelength converting material, even after curing the quantum dot composition, it is possible to disperse the quantum dots in the resin material without forming aggregates while maintaining high luminous efficiency, and it is possible to produce a wavelength converting material with improved reliability. [Example]

[0082] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0083] (Emission wavelength, emission half-width, emission efficiency measurement) In the examples and comparative examples, the fluorescence emission properties of the quantum dots were evaluated by measuring the emission wavelength, fluorescence emission half-width, and fluorescence emission efficiency (internal quantum yield) of the quantum dots at an excitation wavelength of 450 nm using a quantum efficiency measurement system (QE-2100) manufactured by Otsuka Electronics Co., Ltd.

[0084] (reliability test) The obtained wavelength converting material was treated at 85°C and 85% RH (relative humidity) for 100 hours, and its reliability was evaluated by comparing the fluorescence emission efficiency (internal quantum yield) of the wavelength converting material before and after the treatment.

[0085] [Example 1] (Quantum dot manufacturing process) 0.070 g (0.24 mmol) of indium acetate, 0.256 g (0.72 mmol) of palmitic acid, and 4.0 mL of 1-octadecene were added to a flask, and the mixture was heated and stirred at 100° C. under reduced pressure, and degassed for 1 hour while dissolving.

[0086] After cooling the flask to room temperature, nitrogen was purged, and 0.50 mL (0.17 mmol) of a 10 vol% (tris)trimethylsilylphosphine / octadecene solution was added to the flask. The flask was heated to 300 °C and stirred for 20 minutes to synthesize InP semiconductor core particles.

[0087] Next, the flask was cooled to 200°C, and then 0.10 mL (0.02 mmol) of a gallium (III) chloride / octadecene solution was added, followed by heating for 20 minutes.

[0088] The flask was then heated to 240°C, and 4.0 mL (1.2 mmol) of a 0.30 M zinc stearate / octadecene solution was added and stirred for 30 minutes. 0.60 mL (0.90 mmol) of a 1.5 M selenium / trioctylphosphine solution was then added to the flask and stirred for 30 minutes.

[0089] After cooling the flask to room temperature, 0.22 g (1.1 mmol) of zinc acetate was added, and the mixture was heated and stirred under reduced pressure at 100°C for 1 hour while dissolving. After purging the flask with nitrogen, the mixture was heated to 230°C, and 0.48 mL (2.0 mmol) of 1-dodecanethiol was added and stirred for 30 minutes.

[0090] The resulting solution was cooled to room temperature, ethanol was added, and the mixture was centrifuged to precipitate quantum dots consisting of an InP core, a ZnSe shell, and a ZnS shell, and the supernatant was removed.

[0091] Hexane was added to the resulting quantum dot precipitate. Separately, a polar solvent, propylene glycol monomethyl ether acetate (PGMEA), was added. As a result, the resulting precipitate dispersed in hexane, but did not disperse in PGMEA, and the quantum dots settled. This confirmed that the quantum dots do not disperse in polar solvents and have a high affinity for non-polar solvents. Fluorescence emission characteristics were evaluated for the InP / ZnSe / ZnS hexane dispersion. The fluorescence emission characteristics of the resulting quantum dots were an emission wavelength of 536 nm, an emission half-width of 41 nm, and a luminous efficiency of 81%.

[0092] (Quantum dot modification process) In a nitrogen atmosphere, 10 mg of bis[2-(methacryloyloxy)ethyl]phosphate was weighed into a 20 ml vial, and 10 ml of dimethylformamide (DMF) was added and stirred to prepare a bis[2-(methacryloyloxy)ethyl]phosphate solution.

[0093] Furthermore, under a nitrogen atmosphere, 10 g of the resulting 1.0 wt% InP / ZnSe / ZnS hexane dispersion and 10 ml of bis[2-(methacryloyloxy)ethyl]phosphate solution were added to a 50 ml vial. The mass ratio of bis[2-(methacryloyloxy)ethyl]phosphate to InP / ZnSe / ZnS was 10%.

[0094] At this time, the hexane and DMF separated into two phases, with the quantum dots dispersed in the non-polar solvent, hexane. The solution was then heated to 50°C in a nitrogen atmosphere, stirred for 30 minutes, and then cooled to room temperature. The quantum dots then migrated from the non-polar solvent, hexane, to the DMF, confirming that the quantum dots, whose surfaces were modified with bis[2-(methacryloyloxy)ethyl]phosphate, were dispersed in the polar solvent.

[0095] Hexane was added to the resulting quantum dots, and the mixture was centrifuged to precipitate the quantum dots. The supernatant was removed, and propylene glycol monomethyl ether acetate (PGMEA) was added to the resulting quantum dot precipitate. It was confirmed that the quantum dots were dispersed in the polar PGMEA solvent. The resulting quantum dots exhibited fluorescence properties of 537 nm in wavelength, 42 nm in half-width, and 60% in luminescence efficiency.

[0096] (Production of quantum dot compositions) The obtained PGMEA dispersion of quantum dots and methacrylic-modified silicone X-32-3817-3 (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and mixed so that the quantum dots were contained at 20 wt% in nonvolatile content. After mixing, the solvent was removed to obtain a quantum dot composition.

[0097] (Production of wavelength conversion materials) The obtained quantum dot composition was used to prepare a wavelength conversion material. The quantum dot composition was vacuum degassed and applied to a 50 μm thick polyethylene terephthalate (PET) film, and a 100 μm thick quantum dot-containing resin layer was formed using a bar coater. A PET film was then attached to the resin layer for lamination. The film was then irradiated with UV LED radiation at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The quantum dot-containing resin layer was cured by irradiating it with light for 20 seconds to produce a wavelength converting material. The fluorescence emission properties of the obtained wavelength converting material were an emission wavelength of 537 nm, an emission half width of 42 nm, and a luminous efficiency of 53%.

[0098] [Example 2] (Quantum dot manufacturing process) The quantum dot production process was carried out in the same manner as in Example 1, and a hexane dispersion of InP / ZnSe / ZnS was produced.

[0099] (Quantum dot modification process) In a nitrogen atmosphere, a 75 wt % aqueous solution of [2-(methacryloyloxy)ethyl]trimethylammonium chloride was weighed into a 20 ml vial so that 10 mg of [2-(methacryloyloxy)ethyl]trimethylammonium chloride was obtained, and 10 ml of dimethylformamide (DMF) was added and stirred to prepare a DMF solution of [2-(methacryloyloxy)ethyl]trimethylammonium chloride.

[0100] Furthermore, under a nitrogen atmosphere, 10 g of the resulting 1.0 wt% InP / ZnSe / ZnS hexane dispersion and 10 ml of a DMF solution of [2-(methacryloyloxy)ethyl]trimethylammonium chloride were added to a 50 ml vial. The mass ratio of [2-(methacryloyloxy)ethyl]trimethylammonium chloride to InP / ZnSe / ZnS was 10%.

[0101] At this time, the hexane and DMF separated into two phases, with the quantum dots dispersed in the non-polar solvent, hexane. The solution was then heated to 50°C in a nitrogen atmosphere, stirred for 30 minutes, and then cooled to room temperature. The quantum dots migrated from the non-polar solvent, hexane, to the DMF, confirming that the InP / ZnSe / ZnS quantum dots, whose surfaces were modified with [2-(methacryloyloxy)ethyl]trimethylammonium chloride, were dispersed in the polar solvent.

[0102] Hexane was added to the resulting quantum dots, and the mixture was centrifuged to precipitate the quantum dots. The supernatant was removed, and propylene glycol monomethyl ether acetate (PGMEA) was added to the resulting quantum dot precipitate. It was confirmed that the quantum dots were dispersed in the polar PGMEA solvent. The resulting quantum dots exhibited fluorescence properties of 538 nm in wavelength, 43 nm in half-width, and 55% in luminescence efficiency.

[0103] (Production of quantum dot compositions) The obtained PGMEA dispersion of quantum dots and methacrylic-modified silicone X-32-3817-3 (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and mixed so that the quantum dots were contained at 20 wt% in nonvolatile content. After mixing, the solvent was removed to obtain a quantum dot composition.

[0104] (Production of wavelength conversion materials) The obtained quantum dot composition was used to prepare a wavelength conversion material. The quantum dot composition was vacuum degassed and applied to a 50 μm thick polyethylene terephthalate (PET) film, and a 100 μm thick quantum dot-containing resin layer was formed using a bar coater. A PET film was then attached to the resin layer for lamination. The film was then irradiated with UV LED radiation at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The quantum dot-containing resin layer was cured by irradiating it with light for 20 seconds to produce a wavelength converting material. The fluorescence emission properties of the obtained wavelength converting material were an emission wavelength of 538 nm, an emission half width of 43 nm, and a luminous efficiency of 49%.

[0105] [Example 3] (Quantum dot manufacturing process) The quantum dot production process was carried out in the same manner as in Example 1, and a hexane dispersion of InP / ZnSe / ZnS was produced.

[0106] (Quantum dot modification process) In a nitrogen atmosphere, 10 mg of mono[2-(methacryloyloxy)ethyl]maleate was weighed into a 20 ml vial, and 10 ml of dimethylformamide (DMF) was added and stirred to prepare a mono[2-(methacryloyloxy)ethyl]maleate acid solution.

[0107] Furthermore, under a nitrogen atmosphere, 10 g of the resulting 1.0 wt% InP / ZnSe / ZnS hexane dispersion and 10 ml of the mono[2-(methacryloyloxy)ethyl]maleate solution were added to a 50 ml vial. The mass ratio of mono[2-(methacryloyloxy)ethyl]maleate to InP / ZnSe / ZnS was 10%.

[0108] At this time, the hexane and dimethylformamide separated into two phases, with the quantum dots dispersed in the non-polar hexane phase. The solution was then heated to 50°C in a nitrogen atmosphere, stirred for 30 minutes, and then cooled to room temperature. The quantum dots then migrated to the polar dimethylformamide phase, confirming their dispersion. Mono[2-(methacryloyloxy)ethyl]maleate-modified InP / ZnSe / ZnS quantum dots were obtained.

[0109] Hexane was added to the resulting quantum dots, and the mixture was centrifuged to precipitate the quantum dots. The supernatant was removed, and propylene glycol monomethyl ether acetate (PGMEA) was added to the resulting quantum dot precipitate. It was confirmed that the quantum dots were dispersed in the polar PGMEA solvent. The resulting quantum dots exhibited fluorescence properties of 538 nm in wavelength, 42 nm in half-width, and 58% in luminescence efficiency.

[0110] (Production of quantum dot compositions) The obtained PGMEA dispersion of quantum dots and methacrylic-modified silicone X-32-3817-3 (manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed and mixed so that the quantum dots were contained at 20 wt% in nonvolatile content. After mixing, the solvent was removed to obtain a quantum dot composition.

[0111] (Production of wavelength conversion materials) The obtained quantum dot composition was used to prepare a wavelength conversion material. The quantum dot composition was vacuum degassed and applied to a 50 μm thick polyethylene terephthalate (PET) film, and a 100 μm thick quantum dot-containing resin layer was formed using a bar coater. A PET film was then attached to the resin layer for lamination. The film was then irradiated with UV LED radiation at a wavelength of 365 nm and an output of 4000 mW / cm. 2 The quantum dot-containing resin layer was cured by irradiating it with light for 20 seconds to produce a wavelength converting material. The fluorescence emission properties of the obtained wavelength converting material were an emission wavelength of 537 nm, an emission half width of 42 nm, and a luminous efficiency of 51%.

[0112] [Comparative Example] The quantum dot production process was carried out in the same manner as in Example 1, and the resin composition was mixed without surface modification using a compound having a methacryloyloxyethyl group and a hydrophilic group. After the quantum dot production process, methacrylic-modified silicone oil X-32-3817-3 (manufactured by Shin-Etsu Chemical Co., Ltd.) was weighed and mixed into the hexane dispersion so that the quantum dots contained 20 wt% of the nonvolatile content. After mixing, the solvent was removed to obtain a quantum dot composition.

[0113] Using the obtained quantum dot composition, a wavelength converting material was produced by the same production method as in Example 1. The fluorescent emission characteristics of the obtained wavelength converting material were a wavelength of 544 nm, an emission half width of 47 nm, and a luminous efficiency of 28%.

[0114] The results of Examples 1 to 3 and Comparative Example are shown in Table 1. Table 1 shows the dispersion solvent of the quantum dots or quantum dot bodies, the luminous efficiency (internal quantum yield), dispersibility in the PGMEA solvent, the initial value of the luminous efficiency (internal quantum yield) of the wavelength converting material, the luminous efficiency (internal quantum yield) after reliability evaluation, and the presence or absence of aggregates by microscopic observation.

[0115] [Table 1]

[0116] The results in Table 1 confirm that the quantum dot bodies of Examples 1 to 3 precipitated in hexane solvent and dispersed in PGMEA solvent. These results confirm that quantum dot bodies modified with a compound having a methacryloyloxyethyl group and a hydrophilic group have improved affinity for polar solvents such as PGMEA, improving dispersibility. On the other hand, it was confirmed that the quantum dots produced by the method of the comparative example dispersed in hexane solvent, but precipitated and did not disperse in PGMEA solvent, which is a polar solvent.

[0117] Furthermore, when the wavelength converting materials were observed using a microscope, it was found that the wavelength converting materials of Examples 1 to 3 had small aggregates and a small number of them, which is thought to have suppressed the decrease in quantum yield. This is thought to be because in the Examples, the methacryloyl groups of the quantum dot bodies crosslinked with the base polymer of the resin material, effectively suppressing the aggregation of the quantum dots, and the improvement in the dispersibility of the quantum dot bodies was confirmed. On the other hand, in the wavelength converting material of the Comparative Example, many aggregates of about 1 to 100 μm were observed, which is thought to have resulted in the decrease in quantum yield.

[0118] Furthermore, when comparing the results of the reliability test of the wavelength converting materials (treated at 85°C and 85% RH for 100 hours), it is found that the decrease in quantum yield is suppressed in all of the Examples compared to the Comparative Examples, and stability is improved. This is thought to be because the compound having a methacryloyloxyethyl group and a hydrophilic group stably modifies the surface of the quantum dots even in a resin such as a wavelength conversion material.

[0119] As described above, according to the examples of the present invention, it was confirmed that the quantum dot body of the present invention has improved dispersibility in polar solvents. Furthermore, it was confirmed that the quantum dot composition using the quantum dot body of the present invention and the wavelength converting material using the same have high reliability, with the initial value of the fluorescence emission efficiency and deterioration over time under high-temperature and high-humidity conditions being suppressed.

[0120] The present specification includes the following aspects. [1]: A quantum dot body including quantum dots that emit fluorescence when exposed to excitation light, the quantum dots including a semiconductor nanoparticle core and a semiconductor nanoparticle shell that covers the semiconductor nanoparticle core, and the surface of the quantum dots is modified with a compound having a methacryloyloxyethyl group and a hydrophilic group, as shown in the following formula (I): [ka] (R1 represents a hydrophilic group.) [2]: The quantum dot body according to [1] above, wherein the hydrophilic group is selected from the group consisting of quaternary ammonium salts, carboxylates, succinates, isocyanates, maleates, hydrogen phosphates, 1,2,4-benzenetricarboxylates, salts of trimellitic anhydride, phthalates, acetoacetates, and thioctates. [3]: The compound is selected from the group consisting of bis[2-(methacryloyloxy)ethyl]phosphate, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, mono-2-(methacryloyloxy)ethyl succinate, mono[2-(methacryloyloxy)ethyl]maleate, 2-(methacryloyloxy)ethyl isocyanate, (2-methacryloyloxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, 4-MET (4-methacryloxyethyltrimellitic acid), 4-META (4-methacryloxyethyl trimellitic anhydride), mono-2-(methacryloyloxy)ethyl phthalate, bis[2-(methacryloyloxy)ethyl](methyl)ammonio]propane-1-sulfonic acid, 2-(methacryloyloxy)ethyl acetoacetate, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 4-[[2-(methacryloyloxy)ethyl]dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 2-methacryloyloxyethyl thioctic acid, and [2-(methacryloyloxy)ethyl]trimethylammonium methyl sulfate. [4]: The quantum dot body according to [1], [2] or [3] above, wherein the compound is contained in an amount of 0.1 to 50% by mass relative to the quantum dots. [5]: The quantum dot body according to [1], [2], [3] or [4], wherein the compound is contained in an amount of 0.5 to 30% by mass relative to the quantum dots. [6]: A quantum dot composition comprising the quantum dot body of [1], [2], [3], [4] or [5] dispersed in a resin material. [7]: A wavelength converting material comprising a cured product of the quantum dot composition described in [6] above. [8]: A method for producing a quantum dot body according to [1], [2], [3], [4] or [5] above, comprising: a quantum dot production step of producing quantum dots each comprising a semiconductor nanoparticle core and a semiconductor nanoparticle shell covering the semiconductor nanoparticle core; and a quantum dot modification step of modifying the surface of the quantum dot with a compound having a methacryloyloxyethyl group and a hydrophilic group, as represented by formula (I). [9]: A method for producing a quantum dot composition, comprising dispersing the quantum dot bodies produced by the method for producing a quantum dot body according to [8] above in a resin material to produce a quantum dot composition.

[10] : A method for producing a wavelength converting material, comprising curing a quantum dot composition produced by the method for producing a quantum dot composition according to [9] above to produce a wavelength converting material.

[0121] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0122] 1... quantum dot body, 2... semiconductor nanoparticle core, 3... semiconductor nanoparticle shell, 4...Quantum dots, 5...Compound having a methacryloyloxyethyl group and a hydrophilic group.

Claims

1. A quantum dot body including quantum dots that emit fluorescence when exposed to excitation light, the quantum dots include a semiconductor nanoparticle core and a semiconductor nanoparticle shell covering the semiconductor nanoparticle core; A quantum dot body, characterized in that the surface of the quantum dot is modified with a compound having a methacryloyloxyethyl group and a hydrophilic group, represented by the following formula (I): 【Chemistry 1】 (R １ represents a hydrophilic group.)

2. 2. The quantum dot body according to claim 1, wherein the hydrophilic group is selected from the group consisting of quaternary ammonium salts, carboxylates, succinates, isocyanates, maleates, hydrogen phosphates, 1,2,4-benzenetricarboxylates, salts of trimellitic anhydride, phthalates, acetoacetates, and thioctates.

3. The compound is selected from the group consisting of bis[2-(methacryloyloxy)ethyl]phosphate, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, mono-2-(methacryloyloxy)ethyl succinate, mono[2-(methacryloyloxy)ethyl]maleate, 2-(methacryloyloxy)ethyl isocyanate, (2-methacryloyloxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, 4-MET (4-methacryloxyethyltrimellitic acid), 4-META (4-methacryloxyethyl trimellitic anhydride), mono-2-(methacryloyloxy)ethyl phthalate, bis[2-(methacryloyloxy)ethyl](methyl)ammonio]propane-1-sulfonic acid, 2-(methacryloyloxy)ethyl acetoacetate, 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid, 4-[[2-(methacryloyloxy)ethyl]dimethylammonio]butane-1-sulfonic acid, 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propionate, 2-methacryloyloxyethyl thioctic acid, and [2-(methacryloyloxy)ethyl]trimethylammonium methylsulfate.

4. 2. The quantum dot body according to claim 1, wherein the compound is contained in an amount of 0.1 to 50% by mass relative to the quantum dots.

5. 2. The quantum dot body according to claim 1, wherein the compound is contained in an amount of 0.5 to 30% by mass relative to the quantum dots.

6. A quantum dot composition, comprising the quantum dot body according to any one of claims 1 to 5 dispersed in a resin material.

7. A wavelength converting material comprising a cured product of the quantum dot composition according to claim 6.

8. A method for producing a quantum dot body according to any one of claims 1 to 5, a quantum dot production process for producing quantum dots including a semiconductor nanoparticle core and a semiconductor nanoparticle shell covering the semiconductor nanoparticle core; A method for producing a quantum dot body, comprising a quantum dot modification step of modifying the surface of the quantum dot with a compound having a methacryloyloxyethyl group and a hydrophilic group, as represented by formula (I).

9. A method for producing a quantum dot composition, comprising dispersing quantum dot bodies produced by the method for producing a quantum dot body according to claim 8 in a resin material to produce a quantum dot composition.

10. A method for producing a wavelength converting material, comprising curing a quantum dot composition produced by the method for producing a quantum dot composition according to claim 9 to produce a wavelength converting material.

Images