Ink composition

Abstract

To provide an ink composition having high dispersion stability in a plurality of media.SOLUTION: An ink composition 200 contains: photoresponsive nanoparticles 10; a shell-like ligand 20 which has a plurality of bonding parts 30 each comprising an ionic structural unit, and a polymer part 40 which is bonded to the nanoparticles 10 at a plurality of positions by the intermediary of the plurality of bonding parts 30; and a polymerizable compound 50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to ink compositions. [Background technology]

[0002] Photoresponsive nanoparticles such as quantum dots are known to have unique light absorption and emission properties due to their intermediate electronic properties between bulk and discrete systems. Therefore, such photoresponsive nanoparticles are expected to be used in a wide range of industrial applications, including displays, solar cells, and lasers.

[0003] It is expected that photoresponsive nanoparticles will be dispersed in a medium such as a solvent or polymerizable monomer and used as ink, because this will allow easier patterning according to the device to which they will be applied, and easier management of particle size and dispersibility during the procurement, distribution, and manufacturing processes of raw materials. The particle size and dispersibility of photoresponsive nanoparticles in a medium are known to affect the quantum efficiency of quantum dots when made into a device.

[0004] On the other hand, photoresponsive nanoparticles have a small particle size of several nm to several tens of nm and a large specific surface area, so they may be easily aggregated due to the influence of the interface with the medium, and their dispersibility in the medium may not be maintained. Patent Document 1 discloses an ink composition in which quantum dots are dispersed in a medium by using a photopolymerizable compound containing a carboxyl group. In this specification, the medium is a material that serves as a receptacle in which the quantum dots are dispersed, and includes a solvent that has at least fluidity until the stage of receiving a predetermined energy, and a low-molecular polymerizable compound. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-71362 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the ink composition described in Patent Document 1, the dispersibility of the photoresponsive nanoparticles is improved by defining the structure and physical properties of the medium, so the dispersion stability of the ink composition may be restricted by the selection of the medium. An ink composition that ensures dispersion stability in multiple media has been desired.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide an ink composition that ensures dispersion stability in a plurality of media. [Means for solving the problem]

[0008] The ink composition according to an embodiment of the present invention is characterized by comprising: a photoresponsive nanoparticle; a shell-shaped ligand having a plurality of bonding moieties including a structural unit exhibiting ionicity and a polymer moiety bonding to the nanoparticle at a plurality of sites via the plurality of bonding moieties; and a polymerizable compound. Effect of the Invention

[0009] According to the present invention, it is possible to provide an ink composition that ensures dispersion stability in a plurality of media. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a diagram showing (a) the dispersion state of the ink composition according to the first embodiment, and a schematic configuration of a bonding portion (b) and a polymer portion (c). [Diagram 2] FIG. 11 is a diagram showing a dispersion state of an ink composition according to a second embodiment. [Diagram 3] FIG. 2 is a diagram showing the dispersion state of an ink composition according to a first embodiment immediately after preparation (a) and after aging (b). [Figure 4] FIG. 2 shows a schematic structure of an ink composition according to a third embodiment (a) and a wavelength conversion layer according to a fourth embodiment (b). [Diagram 5]FIG. 13 is a diagram showing (a) the dispersion state of an ink composition according to a fifth embodiment, and a schematic configuration of a bonding portion (b) and a polymer portion (c). [Figure 6] FIG. 13 is a diagram showing (a) the dispersion state of an ink composition according to a sixth embodiment, and a schematic configuration of a bonding portion (b) and an organic polymer portion (c). [Figure 7] FIG. 13 is a diagram showing a dispersion state of an ink composition according to a seventh embodiment. [Figure 8] FIG. 13 is a diagram showing the dispersion state of an ink composition according to a second reference embodiment immediately after preparation (a) and after aging (b). [Figure 9] FIG. 2 shows a schematic structure of an ink composition (a) and an eighth wavelength conversion layer (b) according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The dimensions, materials, shapes, relative positions, and so forth of the components described in these embodiments are not intended to limit the scope of the present invention.

[0012] <First embodiment> An ink composition 200 according to a first embodiment will be described with reference to FIGS. 1(a) to (c).

[0013] (Ink composition) 1(a), an ink composition 200 according to this embodiment contains a photoresponsive nanoparticle 10 having a surface coordinated with a shell-like ligand 20, and a polymerizable compound that polymerizes upon receiving energy. The shell-like ligand 20 has a plurality of bonding portions 30 including a structural unit exhibiting ionic properties, and a polymer portion 40 (organic polymer portion 40) that bonds to the nanoparticle 10 at a plurality of points via the plurality of bonding portions 30.

[0014] (Nanoparticles) In this embodiment, the photoresponsive nanoparticles are particles having at least one length of 500 nm or less. The shape of the nanoparticles may be any geometric shape, such as a sphere, cube, rod, disk, etc., and is not particularly limited. The so-called quantum dots having a sphere or cube shape are used.

[0015] Examples of the material of the quantum dot include semiconductor crystals, such as nanoparticles of IV group semiconductors, III-V group, and II-VI group compound semiconductors, and compound semiconductors consisting of a combination of three or more of II, III, IV, V, and VI group elements. Specific examples of materials that emit light in the wavelength range for display elements include CsS, CdSe, CdZnSe, CdSeTe, ZnSe, ZnTeSe, ZnTeS, InP, CuInS2, AgInS2, and Pb-based perovskite. The nanoparticles 10 themselves may be made of different materials in the radial direction. For example, the nanoparticles 10 may have different compositions, crystal structures, etc. in the inner core, middle shell, and outer shell.

[0016] The average particle size of quantum dots is between 2nm and 15nm. When the particle size of quantum dots is reduced to a size equal to or smaller than the Bohr radius of the inherent exciton, the quantum size effect causes the band gap of the quantum dot to change. For example, the Bohr radius of InP, a III-V semiconductor, is said to be about 10nm to 14nm. In other words, if the average particle size of the quantum dots is 15 nm or less, it is possible to control the band gap by the quantum size effect. By making the average particle size of the quantum dots 2 nm or more, it is possible to easily control the crystal growth of the quantum dots in the synthesis of the quantum dots.

[0017] The nanoparticles 10 may be used alone or in combination of two or more kinds.

[0018] The photoresponsive nanoparticle 10 of this embodiment may be a semiconductor nanocrystal having a perovskite crystal structure composed of an A site (monovalent cation), a B site (divalent cation), and an X site (monovalent anion including a halide anion). The perovskite crystal structure is also referred to as a perovskite structure, an ABX3 crystal structure, or an ABX3 structure. The double perovskite crystal structure represented by A2B1B2X6 is also included in the perovskite crystal structure.

[0019] [A site of perovskite structure] A monovalent cation is used at the A site. The monovalent cation used at the A site is the ammonium cation (NH4 + ), and alkylammonium cations with carbon atoms of 6 or less, formamidinium cations (HC(NH2)2 + ), guanidinium cation (C(NH2)3 + ), imidazolium cation, pyridinium cation, pyrrolidinium cation, and other nitrogen-containing organic compound cations; and lithium cation (Li + ), sodium cation (Na + ), potassium cation (K + ), rubidium cation (Rb + ), and the cesium cation (Cs + ) and other alkali metal cations.

[0020] These monovalent cations employed in the A site have a small ionic diameter and are small enough to fit into the crystal lattice, enabling the perovskite compound to form stable three-dimensional crystals.

[0021] A preferred example of an alkylammonium cation having 6 or less carbon atoms is a methylammonium cation (CH3NH3 + ), ethylammonium cation (C2H5NH3 + ), propylammonium cation (C3H7NH3 + ) etc.

[0022] From the viewpoint of obtaining high luminous efficiency, it is preferable to use at least one of methylammonium cation, formamidinium cation, and cesium cation as the A site, and from the viewpoint of suppressing color change, it is more preferable to use cesium cation as the A site. Two or more kinds of these monovalent cations employed as the A site may be used in combination.

[0023] When the A site is a cesium cation, the raw material for the synthesis of the photoresponsive nanocrystal described below may be a cesium salt. As the cesium salt, cesium chloride, cesium bromide, cesium iodide, cesium hydroxide, cesium carbonate, cesium hydrogen carbonate, cesium bicarbonate, cesium formate, cesium acetate, cesium propionate, cesium pivalate, or cesium oxalate may be appropriately used. Among these cesium salt candidates, an appropriate one may be used depending on the synthesis method.

[0024] When the A site is another alkali metal cation, a salt in which the cesium element of the above-mentioned cesium compound is replaced with another alkali metal cation element can be used as the raw material.

[0025] When the A site is a nitrogen-containing organic compound cation such as a methylammonium cation, for example, a neutral compound other than a salt such as methylamine can be used as a raw material. Two or more of these raw materials may be used in combination.

[0026] [Perovskite-type crystal structure B site] The B site of the perovskite crystal structure employs a divalent cation including a divalent transition metal cation or a divalent typical metal cation.

[0027] The divalent transition metal cation is the scandium cation (Sc 2+ ), titanium cation (Ti 2 +), vanadium cation (V 2+ ), chromium cation (Cr 2+ ), manganese cation (Mn 2+ ), iron cation (Fe 2+), cobalt cation (Co 2+ ), nickel cation (Ni 2+ ), copper cation (Cu 2+ ), palladium cation (Pd 2+ ), europium cation (Eu 2+ ), ytterbium cation (Yb 2+ ) will be adopted.

[0028] The divalent typical metal cation is the magnesium cation (Mg 2+ ), calcium cation (Ca 2+ ), strontium cation (Sr 2+ ), barium cation (Ba 2+ ), zinc cation (Zn 2+ ), cadmium cation (Cd 2+ ), germanium cation (Ge 2+ ), tin cation (Sn 2+ ), lead cation (Pb 2+ ) may be adopted.

[0029] Among these divalent cations, divalent typical metal cations are preferred from the viewpoint of growing stable three-dimensional crystals, tin cations or lead cations are more preferred, and lead cations are particularly preferred from the viewpoint of obtaining high luminescence intensity. Two or more of these divalent cations may be used in combination, and the perovskite crystal structure may be a so-called double perovskite structure.

[0030] When the B site is a lead cation, the raw material for the synthesis of the nanoparticles (photoresponsive nanocrystals) described below includes lead compounds, and an appropriate one can be used depending on the synthesis method. As the lead compound, lead chloride, lead bromide, lead iodide, lead oxide, lead hydroxide, lead sulfide, lead carbonate, lead formate, lead acetate, lead 2-ethylhexanoate, lead oleate, lead stearate, lead naphthenate, lead citrate, lead maleate, and lead acetylacetonate are adopted. When the B site is another divalent metal cation, a salt in which the lead element of the above-mentioned lead compound is replaced with another divalent metal cation element can be used as the raw material. Two or more of these raw materials may be used in combination.

[0031] [X site of perovskite crystal structure] X in the perovskite crystal structure is a monovalent anion including a halide anion. The halide anion is a fluoride anion (F - ), chloride anion (Cl - ), bromide anion (Br - ), iodide anion (I - Among them, chloride anion, bromide anion, or iodide anion are preferred because they form stable three-dimensional crystals and emit strong light in the visible light range. The color of the emitted light is blue when chloride anion is used, green when bromide anion is used, and red when iodide anion is used.

[0032] Two or more kinds of halide anions may be used in combination. In particular, when chloride anions, bromide anions, and iodide anions are used in combination, the emission wavelength of the photoresponsive nanocrystal can be set to a desired wavelength depending on the content ratio of the anion species. That is, in particular, when chloride anions, bromide anions, and iodide anions are used in combination, it is preferable because it is possible to obtain an emission spectrum that covers almost the entire range of visible light from blue to red while maintaining a narrow full width at half maximum depending on the content ratio of the anion species.

[0033] The X site may contain a monovalent anion other than a halide anion. Such a monovalent anion other than a halide anion may be a cyanide anion (CN - ), thiocyanate anion (SCN - ), isothiocyanate anion (CNS - ) and other pseudohalide anions. As raw materials for the synthesis of nanoparticles (photoresponsive nanocrystals) described below, salts with counter cations at the A and B sites, such as cesium chloride and lead bromide, and salts with other cations can be selected appropriately according to the synthesis method.

[0034] The nanoparticles (photoresponsive nanocrystals) in this embodiment can be manufactured by the following process. For example, the hot injection method, in which raw material liquids are mixed at high temperature and then rapidly cooled after fine particles are generated to obtain a stable product, and the ligand-assisted reprecipitation method, in which fine particles are obtained by reprecipitation utilizing the difference in miscibility of the product with the solvent, are adopted. In addition, a room temperature synthesis method is also adopted, in which a mixture of A-site raw materials and B-site raw materials, which are non-halogenated materials not containing X-site components, is mixed with a separately prepared X-site raw material liquid under mild conditions at about room temperature to obtain fine particles. Furthermore, the mechanochemical method, in which solid raw materials are reacted by mechanical mixing such as milling or ultrasonic treatment to obtain product fine particles, and the in situ synthesis method, in which a raw material liquid is applied to a substrate and then crystals are directly grown to obtain a reactant, are adopted.

[0035] (Shell Ligand) The shell-shaped ligand 20 provided in the ink composition 200 of this embodiment includes a plurality of bonding portions 30 including structural units exhibiting zwitterionic properties, and a polymer portion 40 (organic polymer portion 40) that is bonded to the nanoparticles 10 at multiple points via the plurality of bonding portions 30.

[0036] The structural unit exhibiting zwitterionic properties is a structural unit exhibiting zwitterionic properties that has a positive charge and a negative charge at non-adjacent positions in the same molecule and has no charge as a whole molecule. The structural unit exhibiting zwitterionic properties includes a betaine structure, a quaternary ammonium salt, and the like. Therefore, the shell-like ligand 20 of this embodiment is in other words a ligand having a plurality of binding parts 30 having a structural unit exhibiting zwitterionic properties and a polymer part 40 coordinated to the photoresponsive nanoparticle 10 via the plurality of binding parts 30. As shown in FIG. 1(b), the binding part 30 includes a betaine structure 30b involved in binding with the nanoparticle 10 and a linking part 30j involved in binding with the polymer part 40 (organic polymer part 40) and including a bond 33 at the end. Furthermore, at least one of the binding part 30 and the polymer part 40 (organic polymer part 40) has organic groups 30a, 40a as shown in FIG. 1(a) to (c). The organic group 30a extends to the outside of the shell structure formed by the polymer portion 40 (organic polymer portion 40) through the discontinuous portion 40d of the polymer portion 40 (organic polymer portion 40) constituting the shell ligand 20. The portion where the polymer portions 40 (organic polymer portions 40) are not connected to each other is shown in FIG. 1(b) as the discontinuous portion 40d. The discontinuous portions 40d may take any of the following forms: a mesh-like or linear extension to the shell-shaped ligand 20; and a discrete existence as independent holes opening in a portion of the polymer portion 40 (organic polymer portion 40) extending two-dimensionally.

[0037] (organic group) The organic groups 30a, 40a may be referred to as organic groups 30a, 40a protruding outward from the shell portion constituted by the polymer portion 40 (organic polymer portion 40). The organic groups protruding outward from the shell portion may be referred to as organic groups present on the opposite side of the nanoparticle 10 with respect to the shell portion. Examples of the organic groups include alkyl groups, heteroalkyl groups, aryl groups, heteroaryl groups, aralkyl groups, and heteroaralkyl groups. Of these, the alkyl groups and heteroalkyl groups may have any of linear, branched, and cyclic structures, and may be partially substituted. In addition, the aryl groups, heteroaryl groups, aralkyl groups, and heteroaralkyl groups may be partially substituted. The linear alkyl groups may be referred to as linear alkyl chains.

[0038] The organic group 30a is an organic group constituting the shell ligand 20, and corresponds to at least a part of A1 to A5 contained in formulas (1) to (3) described later. In other words, similarly, the organic group 40a is an organic group constituting the shell ligand 20, and corresponds to at least a part of R 6、 R7 corresponds to at least a part of the R7. The organic group may be bonded to an atom (e.g., a carbon atom) in the polymer portion to which the linking groups A1, A3, and A5 are bonded. The number of carbon atoms in the organic groups 30a and 40a is selected within a range that ensures compatibility with the polymerizable compound 50 and that allows the bonding portion 30 and the polymer portion 40 (organic polymer portion 40) to be formed as the shell ligand 20. The number of carbon atoms in the organic groups 30a and 40a is preferably 2 or more, more preferably 4 or more.

[0039] The organic groups 30a and 40a according to the present embodiment protrude outward from the shell portion composed of the polymer portion 40, and therefore have the effect of being compatible with the polymerizable compound 50 present outside the light-responsive material 100, and co-disperse the light-responsive material 100 and the polymerizable compound 50. In other words, the organic groups 30a and 40a according to the present embodiment protrude outward from the shell portion composed of the polymer portion 40, and therefore are compatible with the polymerizable compound 50 present outside the shell portion, and co-disperse the light-responsive material 100 and the polymerizable compound 50. Note that the organic groups 30a and 40a may be referred to as peripheral organic groups or radial organic groups due to their structures. In addition, the polymer portion 40 may be referred to as organic polymer portion 40.

[0040] The shell ligand 20 of this embodiment includes an organic group that protrudes outward from the shell portion constituted by the polymer portion 40 (organic polymer portion 40) among the linking groups A1 to A5 and functional groups R6 and R7 contained in the general formulas (1) to (4). The ink composition 200 of this embodiment includes an alkyl group that protrudes outward from the shell portion constituted by the polymer portion 40 (organic polymer portion 40) among the linking groups A1 to A5 and functional groups R6 and R7 contained in the general formulas (1) to (4).

[0041] In the ink composition 200 shown in FIG. 1(a), the nanoparticles 10 with the shell-like ligands 20 coordinated on the surface are stably dispersed in a medium containing a solvent 90 and a polymerizable compound 50 by the organic groups 30a and 40a. The inventor of the present application presumes that this is an effect brought about by the organic groups 30a and 40a having a moderate affinity (miscibility) with the polymerizable compound 50 in the medium and being compatible with it. In this specification, the bond between the binding portion 30 and the nanoparticles 10 corresponds to an ionic bond due to electrostatic interaction. The bond between the binding portion 30 and the nanoparticles 10 may be distinguished from a covalent bond and may be rephrased as a non-covalent bond. In addition, the betaine structure 30b has a pair of sites polarized positively and negatively in the molecule at the branched ends as shown in FIGS. 1(a) to 1(c) and 2, with the intention of clearly indicating the bond due to electrostatic interaction. A pair of positively and negatively polarized sites within the molecule of the betaine structure 30b corresponds to the polarized regions located in the linear structure corresponding to the polarized sites in the structural units represented by formulas (1) and (2), respectively.

[0042] The organic groups 30a, 40a extend outside the shell-shaped polymer portion 40 (organic polymer portion 40), which is presumably caused by the difference in polarity between the organic groups 30a, 40b and the betaine structure 30b. Specifically, the binding portion 30 is coordinated to the nanoparticle 10 by the betaine structure 30b, which has strong polarity, and the organic groups 30a, 40a, which have relatively low polarity, extend approximately radially toward the medium side in which the solvent 90 and the polymerizable compound 50 are present.

[0043] Since the organic groups 30a, 40a extending from the shell-like ligand 20 are compatible with the polymerizable compound 50 in the medium, aggregation of the nanoparticles 10 is unlikely to occur. Furthermore, since the organic groups 30a, 40a extending from the shell-like ligand 20 are compatible with the polymerizable compound 50 in the medium, the nanoparticles 10 are protected by the shell-like ligand 20 even when they are in close proximity to the polar molecules in the solvent 90 and the polymerizable compound 50.

[0044] That is, as shown in Fig. 1(a), a photoresponsive nanoparticle 10 with shell-like ligands 20 coordinated thereto is dispersed in a solvent 90 and is protected from the solvent 90 and a polymerizable compound described below by the shell-like ligands 20. The nanoparticle 10 may also be protected from attack by dispersing components and dissolving components (not shown) dispersed or dissolved in the solvent 90. In other words, a structure exhibiting zwitterionic properties is one form in which a part of the structural unit exhibits ionic properties.

[0045] The shell-shaped ligand 20 having a structural unit including a betaine structure 30b can be strongly coordinated to the surface of the nanoparticle 10 (photoresponsive nanocrystal). In addition, since the shell-shaped ligand 20 has a plurality of betaine structures 30b in the same molecule, even if some of the coordinates are dislodged from the surface of the nanoparticle 10 due to some kind of stimulus, they can be easily coordinated again. Furthermore, the polymer chain of the polymer portion 40 (organic polymer portion 40) exerts a protective function as a shell for the core of the nanoparticle 10, making the nanoparticle 10 less susceptible to the effects of substances such as polar solvents. Therefore, it is considered that the stability of the structure and composition of the nanoparticle 10, which is a photoresponsive nanocrystal, is improved, and the stability of the luminescence characteristics is improved.

[0046] The shell-shaped ligand 20 of this embodiment has at least a binding portion 30 as a portion coordinated to the nanoparticle 10. The shell-shaped ligand 20 is coordinated such that the polymer portion 40 (organic polymer portion 40) covers almost the entire periphery of the nanoparticle 10, leaving some discontinuous portions 40d. The shell-shaped ligand 20 does not necessarily have to cover the periphery of the nanoparticle 10 incompletely, and also includes a form in which the nanoparticle 10 is covered with a coverage rate of 100% as shown in FIG. 2 in the embodiment of the present invention. The coverage rate of the nanoparticle 10 by the shell-shaped ligand 20 is the same as the coverage rate of the nanoparticle 10 by the polymer portion 40 (organic polymer portion 40), and may be expressed in other words as the coverage rate of the nanoparticle 10 by the polymer portion 40 (organic polymer portion 40).

[0047] From the viewpoint of the stability of the nanoparticles 10 against polar solvents, the number average molecular weight of the shell-shaped ligand 20 is preferably 1,000 or more and 50,000 or less. Similarly, the number average molecular weight of the shell-shaped ligand 20 is more preferably 2,000 or more and 30,000 or less. When the ratio of the polymer portion 40 in the shell-shaped ligand 20 is dominant over the ratio of the binding portion 30 in the shell-shaped ligand 20, the number average molecular weight of the polymer portion 40 may be substituted for the number average molecular weight of the shell-shaped ligand 20.

[0048] (joint part) 1(b), the binding portion 30 of the shell ligand 20 includes a betaine structure 30b for binding to the nanoparticle 10, and a linking portion 30j including a bond 33 on the opposite side to the betaine structure 30b. The bond 33 is a portion for binding to the polymer portion 40 (organic polymer portion 40), and corresponds to the bond 43 of the polymer portion 40 (organic polymer portion 40) shown in FIG. 1(c).

[0049] Furthermore, the binding portion 30 has an organic group 30a at the linking portion 30j. The organic group 30a is compatible with the polymerizable compound 50 present in the medium, and is responsible for the dispersion stability of the nanoparticle 10 having the shell-like ligand 20 coordinated thereto in the medium.

[0050] The binding portion 30 of the shell ligand 20 has a structural unit represented by at least one of formulas (1) to (5).

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] In the formulas (1) to (5), R1 to R5, R 12 ~R 15 each independently represents a hydrogen atom or an alkyl group, 11 represents an alkyl group or an aryl group, N represents a nitrogen atom, A1 to A7 represent linking groups, X - represents an anion, Y - is COO - group or SO3 - represents a group, and "*" represents a bond to the polymer moiety.

[0057] In this embodiment, the shell ligand 20 is a copolymer including a polymer portion 40 (organic polymer portion 40) described later and a binding portion 30 having a structural unit.

[0058] R1 to R3 in formula (1), R4 and R5 in formula (2), R in formula (3) 13 ~R 15 The alkyl group in is preferably an alkyl group having 1 to 18 carbon atoms. Examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an n-octyl group, a 2-ethylhexyl group, a dodecyl group, and an octadecyl group. These alkyl groups may be further substituted and may be bonded to each other to form a ring.

[0059] In formula (1), A1 is a linking group that connects the polymer main chain to the phosphate moiety. The linking group A1 is a carbonyl group, an alkylene group, an arylene group, or -COOR 20 -(However, -COOR 20 The carbonyl group in - is bonded to a site other than the phosphate ester site, and R 20represents an alkylene having 1 to 4 carbon atoms). The betaine structure 30b may be directly bonded to the polymer main chain of the organic polymer portion 40 via a single bond.

[0060] The alkylene group in the linking group A1 may be either linear or branched, and is preferably an alkylene group having 1 to 4 carbon atoms. Examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a propylene group, and various butylene groups.

[0061] Examples of the arylene group in the linking group A1 include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, and a naphthalene-2,6-diyl group.

[0062] -COOR in the linking group A1 20 -As-COOR 20 The carbonyl group in - is bonded to a site other than the phosphate ester site, and R 20 is an alkylene having a carbon number of 1 to 4. The alkylene may be either linear or branched.

[0063] These linking groups A1 may be further substituted with other functional groups.

[0064] From the viewpoint of availability of raw materials and ease of production, the linking group A1 is preferably a carbonyl group or -COOR 20 - is more preferable.

[0065] In formula (1), A2 is a linking group that bonds the phosphate moiety and the quaternary ammonium moiety and represents either an alkylene group or an arylene group.

[0066] The alkylene group in the linking group A2 may be either linear or branched, and is preferably an alkylene group having 1 to 4 carbon atoms.

[0067] For example, a methylene group, an ethylene group, a propylene group, various butylene groups, etc. may be mentioned.

[0068] Examples of the arylene group in the linking group A2 include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, and a naphthalene-2,6-diyl group.

[0069] These linking groups may be further substituted.

[0070] From the viewpoint of availability of raw materials and ease of production, the linking group A2 is more preferably a simple alkylene group such as a methylene group or an ethylene group.

[0071] In formula (2), A3 is a linking group that connects the polymer main chain to the quaternary ammonium moiety. The linking group A3 is an alkylene group, an arylene group, an aralkylene group, a-COOR 21 -b,a-CONHR 21 -b, or a-OR 21 -b, etc., where a represents a binding site other than the quaternary ammonium site, b represents a binding site with the quaternary ammonium site, and R 21 represents an alkylene group or an arylene group. The betaine moiety may be directly bonded to the polymer main chain via a single bond.

[0072] The alkylene group in the linking group A3 may be either linear or branched, and is preferably an alkylene group having 1 to 4 carbon atoms, such as a methylene group, an ethylene group, a propylene group, and various butylene groups.

[0073] Examples of the arylene group in the linking group A3 include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, and a naphthalene-2,6-diyl group.

[0074] The aralkylene group in the linking group A3 is, for example, an aralkylene group having 7 to 15 carbon atoms.

[0075] Linking group A3 is a-COOR 21 -b,a-CONHR 21 -b, or a-OR 21 -b, R 21 The alkylene group in may be either linear or branched, and is preferably an alkylene group having 1 to 4 carbon atoms. Examples include a methylene group, an ethylene group, a propylene group, and various butylene groups. Here, a represents a bonding site other than the quaternary ammonium site, b represents a bonding site with the quaternary ammonium site, and R7 represents an alkylene group or an arylene group.

[0076] Also, R 21 Examples of the arylene group in the formula include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, and a naphthalene-2,6-diyl group.

[0077] The linking group A3 may be further substituted.

[0078] The linking group A3 is a-COOR from the viewpoints of availability of raw materials and ease of production. 21 -b or a-CONHR 21 It is more preferable that the formula is -b.

[0079] In formula (2), A4 represents a quaternary ammonium moiety and its counter anion moiety Y - and examples of such linking groups include alkylene groups and arylene groups.

[0080] In formula (3), A5 is a linking group that connects the polymer main chain to the betaine moiety. The linking group A5 is an alkylene group, an arylene group, an aralkylene group, a-COOR 22 -b,a-CONHR 22 -b, or a-OR 22-b, etc., where a represents a binding site other than the betaine site, b represents a binding site with the betaine site, and R 22 represents an alkylene group or an arylene group. The betaine moiety may be directly bonded to the polymer main chain via a single bond.

[0081] The alkylene group in the linking group A4 may be either linear or branched, and is preferably an alkylene group having 1 to 4 carbon atoms.

[0082] For example, a methylene group, an ethylene group, a propylene group, various butylene groups, etc. may be mentioned.

[0083] Examples of the arylene group in the linking group A2 include a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene-1,4-diyl group, a naphthalene-1,5-diyl group, and a naphthalene-2,6-diyl group.

[0084] The linking group A4 may be further substituted.

[0085] The linking group A4 is not particularly limited as mentioned above, but from the viewpoint of availability of raw materials and ease of production, it is more preferable that the linking group A4 is a simple alkylene group such as a methylene group, an ethylene group, or a propylene group.

[0086] In formula (3), Y - is the counter anion of the quaternary ammonium moiety and is covalently bonded to the quaternary ammonium moiety via the linking group A4. Y - is COO - group or SO3 - It is based on

[0087] In addition, in formula (5), R9 to R 11 each independently represents an alkyl group or an aryl group; R 12 represents a hydrogen atom or an alkyl group, N represents a nitrogen atom, A7 represents a linking group, X - represents an anion.

[0088] The shell ligand 20 of this embodiment may employ a binding portion 30 including a structure bonded to the polymer main chain via a linking group A7, as represented by formula (5).

[0089] In formula (5), R 12 The organic group in is preferably an alkyl group having 1 to 4 carbon atoms. Examples of the R9 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. R9 in the formula (5) can be arbitrarily selected from the substituents listed above and a hydrogen atom, but is preferably a hydrogen atom or a methyl group from the viewpoint of the production (polymerizability) of a polymer compound.

[0090] The shell ligand 20 of this embodiment is preferably a copolymer having, together with the binding portion 30, a polymer portion 40 containing a structural unit represented by any one of formulas (6) to (8).

[0091] (Polymer part) The polymer portion 40 (organic polymer portion 40) of the shell ligand 20 is a polymer chain that constitutes a shell structure extending in a straight or branched manner as shown in Fig. 1(c), and the polymer chain has a bond 43. The bond 43 is a portion involved in the bond with the binding portion 30, and corresponds to the bond 33 of the binding portion 30 shown in Fig. 1(b).

[0092] The polymer portion 40 (organic polymer portion 40) may have a plurality of bonds 33. The polymer portions 40 (organic polymer portions 40) are folded and overlapped with adjacent other polymer portions 40 (organic polymer portions 40), thereby becoming entangled with each other and forming a network of organic polymers constituting the shell-shaped ligand 20.

[0093] 1(c), the discontinuous portion 40d may have a variety of forms, such as a slit type that is a gap between adjacent organic polymers 40 and extends linearly or branched, and an independent opening type that corresponds to the mesh of the organic polymer chains that constitute the shell structure.

[0094] Furthermore, the shell-like ligand 20 of this embodiment has an organic group 30a at the connecting portion 30j. The organic group 30a is compatible with the polymerizable compound 50 present in the medium, and is responsible for the dispersion stability of the nanoparticle 10 to which the shell-like ligand 20 is coordinated in the medium.

[0095] A polymer having a structural unit represented by any one of the following formulas (6) to (8) is used as the polymer portion 40 of the shell ligand 20. The polymer portion 40 having the structural unit of formula (6) may be referred to as an organic polymer portion 40, and the polymer portion 44 having the structural unit of either formula (7) or formula (8) may be referred to as an organosilicon polymer portion 44.

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] In the formulas (6) to (8), R 16 , R 18 each independently represents a hydrogen atom or an alkyl group; R 17 represents any one of an alkyl group, a carboxylic acid ester group, a carboxylic acid amide group, an alkoxy group, and an aryl group. 19 represents an alkyl group, and B represents a bond to the bond.

[0100] The shell-like ligand 20 is also considered to be a copolymer of a binding portion 30 including at least one of the structural units of the above-mentioned formulae (1) to (5) and a polymer portion 40 (organic polymer portion 40) including at least one of the structural units of the above-mentioned formulae (6) to (8). Therefore, the shell-like ligand 20 may be referred to as a copolymer 20.

[0101] Here, in formula (6), R 16 represents a hydrogen atom or an alkyl group, and R17 represents an alkyl group, a carboxylic acid ester group, a carboxylic acid amide group, an alkoxy group, or an aryl group.

[0102] In formula (6), R 16 The alkyl group in formula (6) is preferably an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. 16 From the viewpoint of copolymer production (polymerizability), it is preferable that R is a hydrogen atom or a methyl group.

[0103] In formula (6), R 17 The alkyl group in is preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-hexyl group, an n-decyl group, an n-hexadecyl group, an octadecyl group, a docosyl group, and a triacontyl group.

[0104] In formula (6), R 17 Examples of the aryl group in include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0105] In formula (6), R 17 The carboxylic acid ester group in the 24 However, R 24 R represents any one of an alkyl group having 1 to 30 carbon atoms, a phenyl group, and a hydroxyalkyl group having 1 to 30 carbon atoms. 17Examples of the carboxylate group in the formula (I) include a methyl ester group, an ethyl ester group, an n-propyl ester group, an isopropyl ester group, an n-butyl ester group, a tert-butyl ester group, an octyl ester group, a 2-ethylhexyl ester group, a dodecyl ester group, an octadecyl ester group, a docosyl ester group, a triacontyl ester group, a phenyl ester group, and a 2-hydroxyethyl ester group.

[0106] In formula (6), R 17 The carboxylic acid amide group in the formula (I) is -CO-NR 25 R 26 However, R 25 and R 26 R each independently represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or a phenyl group. 17 Examples of the carboxylic acid amide group in the formula (I) include amide groups such as an N-methylamide group, an N,N-dimethylamide group, an N,N-diethylamide group, an N-isopropylamide group, an N-tert-butylamide group, an Nn-decylamide group, an Nn-hexadecylamide group, an N-octadecylamide group, an N-docosylamide group, an N-triacontylamide group, and an N-phenylamide group.

[0107] In formula (6), R 17 The alkoxyl group in R includes an alkoxy group having 1 to 30 carbon atoms and a hydroxyalkoxy group having 1 to 30 carbon atoms. 17 Examples of the alkoxy group in the formula (I) include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an n-hexyloxy group, a cyclohexyloxy group, an n-octyloxy group, a 2-ethylhexyloxy group, a dodecyloxy group, an octadecyloxy group, a docosyloxy group, a triacontyloxy group, and a 2-hydroxyethoxy group.

[0108] In formula (6), R 17The substituent may be further substituted. In this case, examples of the substituent that may be substituted include alkoxy groups such as methoxy and ethoxy, amino groups such as N-methylamino and N,N-dimethylamino, acyl groups such as acetyl, and halogen atoms such as fluorine and chlorine.

[0109] In formula (6), R 16 and R 17 can be arbitrarily selected from the substituents listed above, but it is advisable to select an appropriate substituent according to the application. For example, when the photoresponsive material is used in a highly hydrophobic medium, it is preferable to select a substituent having a long-chain organic group in order to improve dispersibility and stability.

[0110] In formula (7), R 18 can be arbitrarily selected from the substituents listed above and a hydrogen atom, but is preferably a methyl group or an ethyl group from the viewpoint of copolymer production (polymerizability).

[0111] In addition, Si-OR 18 The bond may be hydrolyzed to form a Si-O-Si bond. The Si-O-Si bond may be formed by a condensation reaction between molecules or by a condensation reaction within a molecule.

[0112] In formula (7), R 18 can be arbitrarily selected from the substituents listed above, and it is advisable to select an appropriate substituent depending on the application.

[0113] R 19 The alkyl group in may be an alkyl group having 1 to 30 carbon atoms, and preferably has 1 to 4 carbon atoms. Examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

[0114] For example, when the light-responsive material is used in a highly hydrophobic medium, it is preferable to select a substituent having a long alkyl chain in order to improve dispersibility and stability.

[0115] The copolymerization ratio of the shell-like ligand 20 corresponds to the ratio M30 / M44 of the total number of moles M30 of the bonding portion 30 containing a structural unit represented by any one of formulas (1) to (3) to the total number of moles M44 of the organosilicon polymer portion 44 containing a structural unit represented by formula (7) or (8). The copolymerization ratio of the shell-like ligand 20 is preferably 0.01 / 99.99 or more and 50 / 50 or less, and more preferably 1 / 99 or more and 30 / 70 or less. When the copolymerization composition ratio is within the above range, the shell-like ligand 20 is strongly coordinated to the nanoparticle 10. In the present embodiment, the molar ratio of the structural unit represented by any one of formulas (1) to (3) to the structural unit represented by any one of formulas (6) to (8) in the copolymer is preferably 2.0 / 98 to 50 / 50, more preferably 6 / 94 to 45 / 55, and even more preferably 10 / 90 to 40 / 60.

[0116] When the copolymerization composition ratio is within the above range, the coordination of the shell-like ligand to the nanoparticle is stabilized, and the composition and crystal structure of the photoresponsive nanocrystal are stabilized. In this specification, the photoresponsive nanoparticle may be referred to as a photoresponsive nanocrystal, a photoresponsive nanoparticle, or simply as a nanoparticle or a nanocrystal.

[0117] The content of the shell-like ligand 20 corresponding to the polymer compound is appropriately adjusted according to the type and application of the nanoparticle 10, the binding portion 30, and the polymer portion 40, but is preferably 1 part by mass or more and 1000 parts by mass or less, with the content of the nanoparticle 10 being 100 parts by mass. Furthermore, the content of the shell-like ligand 20 is preferably 3 parts by mass or more and 500 parts by mass or less, more preferably 10 parts by mass or more and 300 parts by mass or less. When the content of the shell-like ligand 20 is less than 1 part by mass, the effect as a shell is not fully exerted, and the stability may not be improved. Furthermore, when the content of the shell-like ligand 20 is more than 1000 parts by mass, the solubility and dispersibility of the shell-like ligand 20 in the medium may decrease, and the stability of the photoresponsive material may not be improved. Furthermore, when the content of the shell-like ligand 20 is more than 1000 parts by mass, the viscosity of the ink composition may increase. The content of each component in the ink composition may be regarded as the charge amount when aggregation, reaction, decomposition, etc. during blending can be ignored.

[0118] The content of the shell-shaped ligand 20 in the ink composition 200 is determined by TG-DTA measurement of a mixture containing the nanoparticles 10 and the shell-shaped ligand 20. The mixture containing the nanoparticles 10 and the shell-shaped ligand 20 can be obtained by adding a poor solvent for the mixture to the ink composition, precipitating the mixture, and then drying it. In addition, when an organic component is contained in the nanoparticles 10, the content of the organic component can be measured separately and subtracted from the ratio of the ink composition 200 to determine the content of the shell-shaped ligand 20. When an organic component is contained in the nanoparticles 10, the A site of the perovskite quantum dots is an organic compound.

[0119] Examples of methods for coordinating the shell-like ligand 20 to the surface of the nanoparticle 10 include a method in which the shell-like ligand 20 is allowed to act after the synthesis of the nanoparticle 10 to exchange it for a ligand described below, and a method in which the shell-like ligand 20 is allowed to coexist during the synthesis of the nanoparticle 10 to cause the ligand to be coordinated. When the shell-like ligand 20 is coordinated by exchanging it for a ligand as described above, the excess free ligand can be removed by centrifugation.

[0120] A method for producing the shell-shaped ligand 20 including the polymer portion 40 (organic polymer portion 40) will be described in detail below. The shell-shaped ligand 20 including the polymer portion 40 (organic polymer portion 40) may be referred to as the shell-shaped ligand 20 in the present specification.

[0121] The method for producing the shell-shaped ligand 20 is not particularly limited as long as the above structure can be obtained, but it can be produced, for example, by the following method (i) or (ii).

[0122] That is, the method (i) for producing the shell-like ligand 20 includes a method in which a monomer containing structural units corresponding to formulas (1) to (3) is produced, and then the monomer is polymerized to produce the shell-like ligand 20. Furthermore, the method (ii) for producing the shell-like ligand 20 includes a method in which a polymer main chain is synthesized, and then the zwitterion moieties of formulas (1) to (3) are bonded to the polymer main chain.

[0123] From the viewpoints of easy availability of monomers and control of the amount of functional groups, it is preferable to produce it by the method shown in (i). Hereinafter, a method for synthesizing the shell-like ligand 20 having the structural unit represented by formula (1) using the method shown in (i) will be described in detail.

[0124] As the monomer for introducing the structural unit represented by formula (1) into the shell ligand 20, a number of derivatives can be mentioned depending on the structure of the linking group A1. As the monomer for introducing the structural unit represented by formula (1) into the shell ligand 20, a vinyl ether derivative, an acrylate derivative, a methacrylate derivative, an α-olefin derivative, an aromatic vinyl derivative, etc. can be used. From the viewpoint of ease of production of the monomer, it is preferable to use an acrylate derivative or a methacrylate derivative as such a monomer.

[0125] The corresponding acrylate or methacrylate derivatives can be prepared by the methods described in the following documents. K. Ishihara and 2 others, "Polymer Journal" (Japan), The Society of Polymer Science, 1990, Vol. 22, p. 355-360.

[0126] The polymerization method of the above monomers includes radical polymerization and ionic polymerization, and living polymerization can also be used for the purpose of controlling the molecular weight distribution or structure. From an industrial perspective, it is preferable to use radical polymerization.

[0127] Radical polymerization can be carried out by using a radical polymerization initiator, irradiating with light such as radiation or laser light, using a photopolymerization initiator in combination with light irradiation, heating, etc. The radical polymerization initiator may be any that can generate radicals and initiate a polymerization reaction, and is selected from compounds that generate radicals by the action of heat, light, radiation, oxidation-reduction reactions, etc.

[0128] For example, azo compounds, organic peroxides, inorganic peroxides, organometallic compounds, photopolymerization initiators, etc. may be mentioned.

[0129] More specifically, examples of the initiator include azo compounds such as 2,2'-azobisisobutyronitrile (AIBN) and 2,2'-azobis(2,4-dimethylvaleronitrile), organic peroxides such as benzoyl peroxide (BPO), tert-butyl peroxypivalate, and tert-butylperoxyisopropyl carbonate, inorganic peroxides such as potassium persulfate and ammonium persulfate, and redox initiators such as hydrogen peroxide-iron(II) salt, BPO-dimethylaniline, and cerium(IV) salt-alcohol. Photopolymerization initiators include acetophenone, benzoin ether, and ketal. Two or more of these radical polymerization initiators may be used in combination.

[0130] The polymerization temperature of the vinyl monomer is not particularly limited and the preferred temperature range varies depending on the type of polymerization initiator used, but polymerization is generally carried out at a temperature of -30°C to 150°C, and a more preferred temperature range is 40°C to 120°C.

[0131] The amount of the polymerization initiator used in this case is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the monomer, and the amount used is preferably adjusted so as to obtain a shell-shaped ligand 20 having a target molecular weight distribution.

[0132] The polymerization method is not particularly limited and may be any method such as solution polymerization, suspension polymerization, emulsion polymerization, dispersion polymerization, precipitation polymerization, and bulk polymerization.

[0133] If necessary, the obtained shell-shaped ligand 20 can be purified by any method, including, but not limited to, reprecipitation, dialysis, column chromatography, and the like.

[0134] The structure of the produced shell-shaped ligand 20 can be identified by various instrumental analyses. Analytical instruments that can be used include a nuclear magnetic resonance (NMR) spectrometer, gel permeation chromatography (GPC) spectrometer, and inductively coupled plasma atomic emission spectrometer (ICP-AES).

[0135] The method for producing the copolymer is not particularly limited as long as the copolymer having the above structure can be obtained, and is the same as that for the shell ligand 20.

[0136] For example, a method for producing a copolymer includes producing a monomer containing a structural unit corresponding to at least one of formulas (1) to (3) and a monomer corresponding to formula (4), and then polymerizing at least one of these monomers to produce the copolymer.

[0137] At this time, it is also possible to further add and polymerize a polymerizable monomer other than the monomer containing a structural unit corresponding to at least any one of formulas (1) to (3) and the monomer corresponding to formula (4).

[0138] (Non-shell ligands) The light-responsive material 100 of this embodiment may have a non-shell ligand bonded to the surface of a core containing semiconductor nanoparticles having a perovskite crystal structure. The non-shell ligand may further improve the stability of dispersion stability, spectroscopic properties, etc. The non-shell ligand may contain at least one compound or ion selected from the group consisting of acids such as carboxylic acids, sulfonic acids, and phosphonic acids, bases such as ammonia and amines, various betaine groups, and salts or ions thereof. From the viewpoint of dispersion stability, it is preferable to use at least one compound or ion selected from the group consisting of organic acids, organic bases, salts or ions thereof, and various betaines as the non-shell ligand.

[0139] The organic acid may be, for example, a branched or straight-chain fatty acid having 1 to 30 carbon atoms. The fatty acid may be either saturated or unsaturated. Among them, from the viewpoint of solubility in a solvent and stability, a straight-chain fatty acid is preferred, and oleic acid is more preferred.

[0140] The salt component in the organic acid salt is not particularly limited as long as it is a metal cation. The salt component in the organic acid salt is preferably an alkali metal cation or an alkaline earth metal cation, more preferably an alkali metal cation. Among the alkali metal cations, sodium and potassium are preferred, and sodium is more preferred.

[0141] Examples of the organic base include branched or linear organic bases having 1 to 30 carbon atoms. The organic base may be either saturated or unsaturated. Among them, from the viewpoints of solubility in a solvent and stability, linear organic bases are preferred, and oleylamine is more preferred.

[0142] Examples of the betaine group include compounds having a phosphobetaine group, a sulfobetaine group, and a carboxybetaine group. From the viewpoints of solubility in a solvent and stability, compounds having a phosphobetaine group or a sulfobetaine group are preferred.

[0143] The non-shell ligands may be used alone or in combination of two or more kinds.

[0144] (Polymerization initiator) In a polymerization reaction, a polymerization initiator and a polymerizable compound are generally used in combination. The polymerization initiator is a compound that generates an active species that initiates a polymerization reaction by irradiation with active energy rays or heat, and a known polymerization initiator can be used. The main active species that initiate a polymerization reaction include a radical polymerization initiator that generates a radical and a cationic polymerization initiator that generates an acid, and these may be used in combination. Examples of photoradical polymerization initiators that generate radicals by active energy rays include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl methyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]butane, and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]butane. acetophenones such as 2-hydroxy-1-[4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl]-2-methylpropan-1-one; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; phosphines such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and other phenyl glyoxylic methyl esters.

[0145] Among the photoradical polymerization initiators, acetophenones such as aminoketones, phosphines, and oxime ester compounds are preferred. These can be used alone or in combination depending on the properties required for the cured product. When using a radical polymerization initiator, the amount used is preferably 0.01 to 100 parts by mass, more preferably 0.1 to 50 parts by mass, based on 100 parts by mass of the total solid content in the composition.

[0146] (polymerizable compound) The ink composition 200 includes a polymerizable compound 50. The polymerizable compound 50 is a component that is accelerated in polymerization upon receiving energy such as light or heat, and imparts viscosity to the ink composition 200 and hardens it. The polymerizable compound 50 may be a radically polymerizable compound or a cationic polymerizable compound. These may be used alone or in combination of two or more types. In addition, either a photopolymerizable compound or a thermally polymerizable compound may be used.

[0147] Examples of the radically polymerizable compound that can be used include monofunctional (meth)acrylate compounds, bifunctional (meth)acrylate compounds, trifunctional or higher (meth)acrylate compounds, hydroxyl group-containing (meth)acrylate compounds, carboxy group-containing (meth)acrylate compounds, and vinyl compounds.

[0148] Examples of monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, benzyl (meth)acrylate, and 3,3,5-trimethylcyclohexyl acrylate. , tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate, isobornyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate can be used.

[0149] Examples of bifunctional (meth)acrylate compounds include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol 200 di(meth)acrylate, polyethylene glycol 300 di(meth)acrylate, polyethylene glycol 400 di(meth)acrylate, and polyethylene glycol 600. Di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol 400 di(meth)acrylate, polypropylene glycol 700 di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol PO-modified di(meth)acrylate, EO-modified bisphenol A di(meth)acrylate, PO-modified bisphenol A di(meth)acrylate, and hydroxypivalic acid neopentyl glycol di(meth)acrylate can be used.

[0150] Examples of trifunctional or higher (meth)acrylate compounds that can be used include trimethylolpropane triacrylate, trimethylolpropane EO-modified tri(meth)acrylate, trimethylolpropane PO-modified tri(meth)acrylate, glycerin propoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, and EO-modified pentaerythritol tetraacrylate.

[0151] Examples of the hydroxyl group-containing (meth)acrylate compound include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethyl acryloyl phosphate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, dipropylene glycol (meth)acrylate, fatty acid-modified glycidyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, glycerin di(meth)acrylate, and 2-hydroxy-3-acryloyloxypropyl methacrylate.

[0152] Examples of the carboxy group-containing (meth)acrylate compound that can be used include β-carboxyethyl (meth)acrylate, succinic acid mono(meth)acryloyloxyethyl ester, and ω-carboxypolycaprolactone mono(meth)acrylate.

[0153] Examples of the vinyl-based compound that can be used include vinyl acetate, vinyl benzoate, vinyl pivalate, vinyl butyrate, vinyl methacrylate, and N-vinylpyrrolidone.

[0154] The cationic polymerizable compound may be either a photopolymerizable or a thermally polymerizable compound. These may be used alone or in combination of two or more. Representative cationic polymerizable compounds include, for example, epoxy compounds, oxacene compounds, and vinyl ether compounds.

[0155] The amount of the polymerizable compound including the radically polymerizable compound and the cationic polymerizable compound used is preferably 1 to 99 parts by mass, more preferably 3 to 90 parts by mass, and even more preferably 5 to 80 parts by mass, relative to 200 parts by mass of the ink composition.

[0156] (solvent) The ink composition 200 may contain a solvent 90 as necessary. Examples of the solvent 90 that can be used include alkanes such as pentane and hexane, cycloalkanes such as cyclopentane and cyclohexane, esters such as ethyl acetate, butyl acetate, and benzyl acetate, ethers such as diethyl ether and tetrahydrofuran, ketones such as cyclohexanone and acetone, and alcohols such as methanol, ethanol, isopropanol, butanol, and hexanol. In addition, monoacetate compounds such as diethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate, diacetate compounds such as 1,4-butanediol diacetate and propylene glycol diacetate, and triacetate compounds such as glyceryl triacetate can also be used.

[0157] The solvent 90 has a boiling point of 300° C. or less because the solvent can be easily removed before curing the polymerizable compound 50. The solvent 90 may be referred to as the solvent 90 in other words.

[0158] (Other additives) In this embodiment, the ink composition may be used in combination with an oxygen remover, an antioxidant, a scattering agent such as titanium oxide, a surfactant, an anti-mold agent, a light stabilizer, or other additives that impart various properties, a diluting solvent, or the like, as necessary.

[0159] (Wavelength conversion material) The wavelength conversion member of this embodiment is a member obtained by curing an ink composition 200 (ink composition 200) containing a photoresponsive material 100 and a polymerizable compound 50 in a co-dispersed state as shown in FIG. 8(a) on a substrate. The wavelength conversion member has a layered form supported by another member, and may be referred to as a wavelength conversion layer 520 as shown in FIG. 8(b). Support forms include a laminated form and a dispersed form dispersed in a matrix material. The wavelength conversion layer 520 may be formed by applying the ink composition 200 onto a support member (substrate) and curing it to form a film, sheet, or patterned pixels.

[0160] (Method of forming wavelength conversion layer) The method for forming the wavelength conversion layer 520 is not particularly limited, and examples thereof include a method in which a photoresponsive material composition is applied onto a substrate, and then pre-dried as necessary, and further, if necessary, heated or irradiated with active energy rays to cure the film. The thickness of the cured wavelength conversion layer is preferably 0.1 to 200 μm, more preferably 1 to 100 μm.

[0161] The active energy ray in the active energy ray irradiation is appropriately selected from electromagnetic waves such as heat rays, ultraviolet rays, visible rays, near infrared rays, and electron beams that reduce fluidity and promote curing through polymerization, crosslinking, drying, etc. As a light source for applying active energy rays, a light source having a main wavelength of emission in the wavelength region of 100 to 450 nm is preferable. Examples of such light sources include ultra-high pressure mercury lamps, high pressure mercury lamps, medium pressure mercury lamps, mercury xenon lamps, metal halide lamps, high power metal halide lamps, xenon lamps, pulsed xenon lamps, deuterium lamps, fluorescent lamps, ND-YAG triple wave lasers, HE-CD lasers, nitrogen lasers, XE-Cl excimer lasers, XE-F excimer lasers, semiconductor pumped solid state lasers, and LED lamp light sources having emission wavelengths of 365 nm, 375 nm, 385 nm, 395 nm, and 405 nm.

[0162] <Second embodiment> Fig. 2 is a diagram showing a dispersion state of an ink composition 220 according to the second embodiment. As shown in Fig. 2, the ink composition 220 according to this embodiment has a form in which the entire sphere (corresponding to a solid angle of 4π) of the nanoparticle 10 is covered with the shell-like ligand 20. The ink composition 220 according to this embodiment differs from the ink composition 200 according to the first embodiment in that the organic group 40a compatible with the polymerizable compound 50 contained in the medium is from the polymer portion 40 (organic polymer portion 40), and no organic group from the bond portion 30 is included.

[0163] The shell ligand 20 of this modified embodiment has at least a portion coordinated to the nanoparticle 10, similar to the shell ligand 20 of the first embodiment. The shell ligand 20 in the ink composition 220 has a discontinuous portion (not shown) that does not cover a portion of the nanoparticle 10. The discontinuous portion (not shown) that does not cover a portion of the nanoparticle 10 includes a mesh-like hole formed by overlapping linear polymer portions 40 (organic polymer portions 40) that extend in different directions along the shell of the shell-like ligand 20.

[0164] <First reference form> 3(a) and (b) are diagrams showing the dispersion state of the ink composition 800 according to the first reference embodiment immediately after preparation (a) and after aging (b). The nanoparticles 10 corresponding to the quantum dots QD of the ink composition 800 according to this reference embodiment have a betaine structure 30b, but do not have a shell ligand 20, and only non-shell ligands 60 having a linear or branched skeleton are coordinated. Only the non-shell ligands 60 extending substantially radially from the surface of the nanoparticles 10 are coordinated to the surface of the nanoparticles 10.

[0165] Therefore, although the non-shell ligand 60 contained in the ink composition 800 has an organic group 60a, the bond related to the coordination with the nanoparticles 10 is not strong compared to the ink composition 200 according to the first embodiment. As a result, it is presumed that the ink composition 800 is easily attacked by the solvent 90 containing polar molecules, and the semiconductor composition of a part of the nanoparticles 10 may change. In addition, although the non-shell ligand 60 contains the organic group 60a, it is easily detached from the nanoparticles 10 in the ink composition 800, and compatibility with the polymerizable compound 50 in the medium cannot be sufficiently ensured, and it is presumed that aggregation of the nanoparticles 10 may occur as shown in FIG. 3(b). The aggregation of the nanoparticles 10 constitutes coarse secondary particles, which is considered to be a factor in reducing the quantum confinement effect and the quantum yield related to light emission.

[0166] <Third embodiment> FIG. 8(a) is a diagram showing the dispersion state of the ink composition 220 (light-responsive composition 220) according to the third embodiment.

[0167] The ink composition 220 increases in viscosity and hardens due to polymerization of the polymerizable compound contained therein. Therefore, the ink composition 220 in FIG. 8(a), which corresponds to the stage before curing, is in the form of an ink having fluidity, and may be referred to as the ink composition 220. Curing may be referred to as solidifying. The ink composition 220 contains the light-responsive material 100 and the polymerizable compound 50, and may be referred to as the luminescent composition 220 or the light-responsive composition 220. The ink composition 220 is in a state in which the light-responsive material 100 and the polymerizable compound 50 are co-dispersed in the solvent 90.

[0168] 8(a), the ink composition 220 of this embodiment has a form in which the entire sphere (corresponding to a solid angle of 4π) of the nanoparticle 10 is covered with the shell-like ligand 20. In the ink composition 220 of this embodiment, the organic group 40a that is compatible with the polymerizable compound 50 contained in the medium is part of the structure contained in the polymer portion 40 (organic polymer portion 40).

[0169] The shell-shaped ligand 20 in this modified form has at least a portion coordinated to the nanoparticle 10. The shell-shaped ligand 20 in the ink composition 220 has discontinuous portions (not shown) that do not cover a portion of the nanoparticle 10. The discontinuous portions (not shown) that do not cover a portion of the nanoparticle 10 include mesh-like holes formed by overlapping linear polymer portions 40 (organic polymer portions 40) that extend in different directions along the shell of the shell-shaped ligand 20.

[0170] A modification of this embodiment also includes an embodiment in which an organic group is provided as a part of the structure of the binding portion. In such a modification (not shown), the organic group protrudes outward from the shell ligand through the mesh of the network structure formed by the polymer portion.

[0171] The ink composition 220 forms a film-like wavelength converting portion 526 by hardening the polymerizable compound 50 through polymerization.

[0172] <Fourth embodiment> FIG. 8(b) shows a cross-sectional structure of a display element 500 according to the fourth embodiment.

[0173] The display element 500 has a light-emitting layer 510, a dielectric multilayer film 517, and a wavelength conversion layer 520 stacked in a stacking direction D1. The downstream side in the stacking direction D1 corresponds to the side where a user who views an image drawn on the display element is positioned. The wavelength conversion layer 520 is separated from the wavelength conversion layers corresponding to adjacent elements by a black matrix BM that separates the pixels.

[0174] As described above, the ink composition 220 is cured together with the polymerizable compound 50 by carrying out a polymerization process such as a photopolymerization process. The ink composition 220 is cured to form the wavelength conversion layer 520 of the display element 500 that satisfies predetermined dimensions. In other words, the wavelength conversion layer 520 is a layer that is solidified by being cured together with the polymerizable compound 50.

[0175] The light emitting layer 510 corresponds to a light source that emits light L1 of a first wavelength λ1. The wavelength conversion layer 520 has an optical coupling surface 522 that is optically coupled to the light emitting layer 510 on the side of the light emitting layer 510, and has an extraction surface 524 on the opposite side of the light emitting layer 510 that is converted by the wavelength conversion layer 520 and extracts the secondary light L2.

[0176] The wavelength conversion layer 520 of this embodiment receives primary light L1 of wavelength λ1 propagating through the dielectric multilayer film 917. The dielectric multilayer film 517 provides the display element 500 with the spectral transmission characteristics of the primary light from the light emitting layer 510 and the spectral reflection characteristics of secondary light L2 of wavelength λ2 emitted in the wavelength conversion layer 520. The wavelength λ2 of the secondary light L2 is longer than the wavelength λ1 of the primary light L1.

[0177] The dielectric multilayer film 917 can be replaced with another optical member having optical transparency to the first wavelength λ1 emitted by the light emitting layer 510. Also, another optical member (not shown) can be disposed in front of the extraction surface 524 (opposite side to the light emitting layer 510).

[0178] (Storage method) Since the photoresponsive properties of the photoresponsive nanoparticles are easily deteriorated not only by polar solvents but also by light and heat, it is preferable to store the ink composition 220 and the photoresponsive material 100 according to this embodiment in a refrigerator or a dark room that is shielded from external light. By doing so, it is possible to reduce the deterioration of the ink composition 220 and the photoresponsive material 100 according to this embodiment due to light and heat during storage.

[0179] ((Measurement method)) The various physical property measurements can be carried out as follows.

[0180] ((Molecular weight distribution measurement)) The molecular weight distribution of the shell-shaped ligand can be calculated in terms of monodisperse polymethyl methacrylate by gel permeation chromatography (GPC). Measurement of the molecular weight by GPC can be performed, for example, as shown below.

[0181] The sample is added to the eluent below so that the sample concentration becomes 1% by mass, and the solution is left to stand at room temperature for 24 hours to dissolve. The solution is then filtered through a solvent-resistant membrane filter with a pore size of 0.45 μm to obtain the sample solution, which is then measured under the following conditions. Apparatus: Agilent 1260 infinity system (Agilent Technologies) Column: PFG analytical linear M columns (PSS) Eluent: 2,2,2-trifluoroethanol Flow rate: 0.2ml / min Oven temperature: 40℃ Sample injection volume: 20 μL

[0182] In calculating the molecular weight distribution of the sample, a molecular weight calibration curve prepared using a standard polymethyl methacrylate resin (EasiVial PM Polymer Standard Kit manufactured by Agilent Technologies) is used.

[0183] ((composition analysis)) The compositional analysis of the shell-shaped ligand can be carried out using nuclear magnetic resonance (NMR). For example, 1H-NMR and 13C-NMR spectrum measurements are carried out using an ECA-600 (600 MHz) manufactured by JEOL Ltd. The measurements are carried out at 25°C in a deuterated solvent containing tetramethylsilane as an internal standard. The chemical shift value is read as a ppm shift value (δ value) with the internal standard tetramethylsilane set to 0.

[0184] ((Crystal structure analysis)) The crystal structure and composition of the nanoparticles 10 can be analyzed by X-ray photoelectron spectroscopy (XPS). For example, the crystal structure can be analyzed by measuring the X-ray diffraction pattern using a RINT 2100 (manufactured by Rigaku).

[0185] ((composition analysis)) The composition of the nanoparticles 10 can be analyzed using XPS and ICP optical emission spectroscopy. The molar ratio of A and B can be measured from the signal intensity of XPS, and the concentration of X can be measured from the emission intensity of ICP emission spectrometry (for example, CIROS CCD (manufactured by SPECTRO)).

[0186] ((Method of confirming that ligands are coordinated to nanoparticles)) Whether or not the shell-like ligand 20 is coordinated to the nanoparticle 10 can be confirmed by infrared absorption spectroscopy (IR method). If the IR absorption spectrum of the ink composition is measured and a signal at the bond is observed, it can be confirmed that the shell-like ligand 20 is coordinated to the nanoparticle 10. At that time, the signal at the bond may shift by about several nm due to the coordination. The nanoparticles may be alternatively referred to as photoresponsive nanoparticles, photoresponsive nanocrystals, luminescent nanoparticles, luminescent nanocrystals, or nanocrystals.

[0187] Coordination can also be confirmed by observation with a transmission electron microscope (TEM). Normally, photoresponsive nanoparticles with a perovskite crystal structure are observed to be regularly arranged, but when shell-like ligands are coordinated, the arrangement is observed to be disordered due to steric repulsion between the shell-like ligands themselves and between the shell-like ligands and the substrate. This also allows the coordination to be confirmed.

[0188] ((Photoresponsive nanoparticle content)) The content of the photoresponsive nanoparticles in the photoresponsive material or composition can be measured using ICP emission spectroscopy and NMR. For example, the amount of Pb is measured from the emission intensity of ICP emission spectroscopy, and the amount of ligand is measured from the signal intensity of NMR. The content of the photoresponsive nanoparticles can be measured from the composition information of the photoresponsive nanoparticles obtained by the above method.

[0189] ((Polymer compound content)) The content of the polymer compound in the photoresponsive material or composition can be determined from the integrated intensity of NMR in addition to the above-mentioned TG-DTA measurement.

[0190] ((Betaine group content in polymer compound)) The content of betaine groups in a polymer compound can be determined from the NMR integrated intensity ratio between the betaine portion and other portions in the polymer compound.

[0191] ((mmol of betaine groups per gram of photoresponsive nanoparticles)) The number of mmoles of betaine groups per 1 g of photoresponsive nanoparticles can be calculated from the content of photoresponsive nanoparticles determined by the above method, the content of polymer compound, and the content of betaine groups in the polymer compound.

[0192] (Analysis of anion species contained in quaternary ammonium salts) In addition, the analysis of anion species contained in quaternary ammonium salts can be performed using combustion decomposition-ion chromatography. The sample is burned in an oxygen-containing air stream, the generated gas is collected, and the generated ions are separated and quantified by ion chromatography to analyze the anion species. For example, an automatic sample combustion device AQF-2100 (manufactured by Mitsubishi Analytic) and an ion chromatograph IC-2010 (manufactured by Tosoh) can be used.

[0193] <Fifth embodiment> Next, an ink composition 330 according to a fifth embodiment will be described with reference to FIGS. 5(a), (b) and (c).

[0194] The ink composition 330 of this embodiment differs from the ink composition 200 of the first embodiment and the ink composition 220 of the second embodiment in that the ink composition 330 contains a quaternary ammonium salt as a structural unit exhibiting zwitterionicity.

[0195] (Shell Ligand) 5(a), an ink composition 330 according to this embodiment includes a photoresponsive nanoparticle 10 and a shell-like ligand 20 that is coordinated by binding to the surface of the nanoparticle 10 at multiple sites. The shell-like ligand 20 includes multiple binding moieties 30 including a quaternary ammonium salt 30b, and a polymer moiety 40 that is bound to the nanoparticle 10 at multiple sites via the multiple binding moieties 30.

[0196] Here, the quaternary ammonium salt 30b refers to a salt of a cation in which an ammonia molecule is tetrasubstituted with a carbon-containing substituent and another anion. The binding portion 30 includes a quaternary ammonium salt 30b that is bound to the nanoparticle 10, and a linking portion 30j that is bound to the polymer portion 40 and includes a bond 33 at the end. At least one of the binding portion 30 and the polymer portion 40 has organic groups 30a, 40a, as shown in FIGS. 5(a) to 5(c). The organic group 30a extends to the outside of the shell through the discontinuous portion 40d of the polymer portion 40 that constitutes the shell-like ligand 20. The portion in which the polymer portions 40 are not connected to each other is shown as the discontinuous portion 40d in FIG. 1(b). The discontinuous portion 40d may extend in the shell-like ligand 20 in a mesh-like or linear manner, or may exist discretely as an independent hole that opens in a part of the polymer portion 40 that spreads two-dimensionally.

[0197] The ink composition 330 shown in FIG. 5(a) is stably dispersed in a medium containing a medium 90 and a polymerizable compound 50 due to the organic groups 30a and 40a of the shell-like ligand 20 that is coordinated to cover the nanoparticle 10. The inventor of the present application presumes that this is an effect brought about by the organic groups 30a and 40a having a moderate affinity (miscibility) with the polymerizable compound 50 in the medium and being compatible with it. In this specification, the bond between the binding portion 30 and the nanoparticle 10 corresponds to an ionic bond due to electrostatic interaction. The bond between the binding portion 30 and the nanoparticle 10 may be distinguished from a covalent bond and may be rephrased as a non-covalent bond.

[0198] The organic groups 30a, 40a extend outside the shell-shaped polymer portion 40, which is presumably caused by the difference in polarity between the organic groups 30a, 40a and the quaternary ammonium salt 30b. Specifically, the binding portion 30 is coordinated to the nanoparticle 10 by the quaternary ammonium salt 30b, which has strong polarity, and the organic groups 30a, 40a, which have relatively low polarity, extend approximately radially toward the medium side where the medium 90 and the polymerizable compound 50 are present.

[0199] Since the organic groups 30a, 40a extending from the shell-like ligand 20 are compatible with the polymerizable compound 50 in the medium, aggregation of the nanoparticles 10 is unlikely to occur. Furthermore, since the organic groups 30a, 40a extending from the shell-like ligand 20 are compatible with the polymerizable compound 50 in the medium, the nanoparticles 10 are protected by the shell-like ligand 20 even when they are in close proximity to the polar molecules and the polymerizable compound 50 in the medium 90.

[0200] 5(a), a photoresponsive nanoparticle 10 with shell-like ligands 20 coordinated therearound is dispersed in a medium 90 and is protected from the medium 90 and a polymerizable compound described below by the shell-like ligands 20. The nanoparticle 10 may also be protected from attack by dispersing components and dissolving components (not shown) dispersed or dissolved in the medium 90.

[0201] The shell-shaped ligand 20 having a structural unit containing a quaternary ammonium salt 30b can be strongly coordinated to the surface of the nanoparticle 10 (luminescent nanocrystal). In addition, since the shell-shaped ligand 20 has a plurality of quaternary ammonium salts 30b in the same molecule, even if some of the coordinated ligands are dislodged from the surface of the nanoparticle 10 due to some kind of stimulus, they can be easily coordinated again. Furthermore, the polymer chains of the polymer portion 40 exert a protective function as a shell for the core of the nanoparticle 10, making the nanoparticle 10 less susceptible to the effects of substances such as polar solvents. This is believed to improve the stability of the structure and composition of the nanoparticles 10, which are luminescent nanocrystals, and thus improve the stability of the luminescence characteristics.

[0202] Sixth embodiment Next, an ink composition 400 according to a sixth embodiment will be described with reference to FIGS. 6(a), (b) and (c).

[0203] The ink composition 400 of this embodiment differs from the ink compositions 200, 220, and 330 of the first, third, and fifth embodiments in that it contains an organosilicon polymer portion 44 that contains an organosilicon polymer as a structural unit corresponding to the polymer portion.

[0204] (Organosilicon Polymer Division) The organosilicon polymer portion 44 of the shell ligand 20 of this embodiment has a polymer chain that forms a shell structure that spreads linearly or branchedly, as shown in Figures 6(a) and (c). Such a polymer chain has a bond 43. The bond 43 is a portion involved in bonding with the bonding portion 30, and corresponds to the bond 33 of the bonding portion 30 shown in Figure 6(b). The shell ligand 20 having the organosilicon polymer portion 44, and the organosilicon polymer portion 44, may be referred to as a silica shell 44.

[0205] The organosilicon polymer portion 44 may have multiple bonds 33. The organosilicon polymer portions 44 overlap with adjacent organosilicon polymer portions 44 and become entangled with each other, forming a network of organic polymers that constitute the shell-like ligand 20.

[0206] The discontinuous portion 44u shown in FIG. 6(a) may have a variety of forms, including a slit type that is a gap between adjacent organic polymers 40 and extends linearly or branched, and an independent opening type that corresponds to the mesh of the organic polymer chains that constitute the shell structure.

[0207] The organosilicon polymer part 44 includes a polysiloxane compound having Si-O- linked to the main chain. The organosilicon polymer part 44 may be a copolymer having a structural unit represented by at least one of formulas (7) and (8), and preferably includes a copolymer having a structural unit represented by formulas (7) and (8). The organosilicon polymer part 44 may be referred to as a polysiloxane compound part 44 or an organosilicon compound part 44.

[0208] [ka]

[0209] Here, in formula (7), R 18 represents a hydrogen atom or an alkyl group, and B represents a bond to the bond.

[0210] [ka]

[0211] Here, in formula (8), R 19 represents an alkyl group, and B represents a bond to the bond.

[0212] In formula (7), R 18 can be arbitrarily selected from the substituents listed above and a hydrogen atom, but is preferably a methyl group or an ethyl group from the viewpoint of copolymer production (polymerizability).

[0213] In addition, Si-OR 18 The bond may be hydrolyzed to form a Si-O-Si bond. The Si-O-Si bond may be formed by an intermolecular condensation reaction or an intramolecular condensation reaction.

[0214] In formula (7), R 18 can be arbitrarily selected from the substituents listed above, and it is advisable to select an appropriate substituent depending on the application.

[0215] R 19The alkyl group in may be an alkyl group having 1 to 30 carbon atoms, and preferably has 1 to 4 carbon atoms. Examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

[0216] In formula (7), R 18 can be arbitrarily selected from the substituents listed above and a hydrogen atom, but is preferably a methyl group or an ethyl group from the viewpoint of copolymer production (polymerizability).

[0217] In addition, Si-OR 18 The bond may be hydrolyzed to form a Si-O-Si bond. The Si-O-Si bond may be formed by a condensation reaction between molecules or by a condensation reaction within a molecule.

[0218] In formula (7), R 18 can be arbitrarily selected from the substituents listed above, and it is advisable to select an appropriate substituent depending on the application.

[0219] R 19 The alkyl group in may be an alkyl group having 1 to 30 carbon atoms, and preferably has 1 to 4 carbon atoms. Examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

[0220] In formula (7), R 18 can be arbitrarily selected from the substituents listed above, and it is advisable to select an appropriate substituent depending on the application.

[0221] R 19 The alkyl group in may be an alkyl group having 1 to 30 carbon atoms, and preferably has 1 to 4 carbon atoms. Examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

[0222] The copolymerization ratio of the shell-like ligand 20 corresponds to the ratio M30 / M44 of the total number of moles M30 of the bonding portion 30 containing the structural unit represented by any one of formulas (1) to (5) to the total number of moles M44 of the organosilicon polymer portion 44 containing the structural unit represented by formula (7) or (8). The copolymerization ratio of the shell-like ligand 20 is preferably 0.01 / 99.99 or more and 50 / 50 or less, more preferably 1 / 99 or more and 30 / 70 or less. When the copolymerization composition ratio is within the above range, the shell-like ligand 20 is strongly coordinated to the nanoparticle 10, thereby improving the stability of the photoresponsive material 100.

[0223] The content of the organosilicon polymer part 44 may be adjusted appropriately according to the type and application of the nanoparticle 10 and the organosilicon polymer part 44, but is preferably 0.01% by weight to 10% by weight relative to the content of the nanoparticle 10. The content of the organosilicon polymer part 44 is preferably 0.05% by weight to 5% by weight, more preferably 0.1% by weight to 3% by weight. If the content of the organosilicon polymer part 44 is less than 0.01% by weight, the effect as a shell may not be fully exerted, and the dispersion stability of the nanoparticle 10 may not be maintained. If the content of the organosilicon polymer part 44 is more than 10% by weight, the solubility and dispersibility of the organosilicon polymer part in the medium may decrease, and the stability of the photoresponsive material may not be improved.

[0224] The method for producing the organosilicon polymer part 44 is not particularly limited, but it can be produced, for example, by the following method.

[0225] The organosilicon polymer portion 44 can be obtained by hydrolyzing betaine silane, in which an alkylsilane main chain is linked to a betaine structure, to generate a Si-O-Si bond.

[0226] One method for bonding the organosilicon polymer part 44 to the surface of the nanoparticle 10 is to coordinate a silane compound containing a betaine structure 30b (hereinafter, betaine silane compound) after the synthesis of the nanoparticle 10, and then form the organosilicon polymer part 44 by hydrolysis. Another method for bonding the organosilicon polymer part 44 to the surface of the nanoparticle 10 is to bond the nanoparticle 10 to the surface by coexisting a silane compound containing a betaine structure 30b during the synthesis of the nanoparticle 10, and then form the organosilicon polymer part by hydrolysis after purification.

[0227] In the case of betaine silane compounds, the type of counter anion at the quaternary ammonium moiety is SO3 - Sulfobetaine silane compound, COO - The carboxybetaine silane compound, HPO3 - A phosphobetaine silane compound, which is a group, can be used.

[0228] Sulfobetaine silane can be produced, for example, by the method described in the following document. Langmuir 30.38(2014):11386-11393. The sulfobetaine silane compound can be obtained by reacting an aminoalkylsilane with a sultone. When [3-(N,N-dimethylamino)propyl]trimethoxysilane is used as the aminoalkylsilane, it is preferable because it forms a quaternary ammonium. As the sultone, a 4-membered ring or 5-membered ring sultone can be used. The quaternary ammonium moiety and its counter anion moiety Y - The number of carbon atoms in the alkylene group of the linking group A2 or linking group A4 that bonds the above is 3 when a four-membered ring sultone is used, and 4 when a five-membered ring sultone is used.

[0229] The carboxybetaine silane compound can be produced, for example, by the method described in the following document. RSC advances 6.30(2016):24827-24834.

[0230] The phosphobetaine silane compound can be produced, for example, by the method described in the following document. ACS applied materials & interfaces 2.10(2010):2781-2788.

[0231] The structures of the produced organosilicon polymer and its raw material, the betaine silane compound, can be identified using various instrumental analyses, such as nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0232] In order to make the light-responsive material of this embodiment into a light-responsive material composition that hardens in response to an external stimulus, a polymerizable monomer can also be used as a medium.

[0233] <Seventh embodiment> Next, an ink composition 440 according to a seventh embodiment will be described with reference to FIG.

[0234] 7, the ink composition 440 of this embodiment has a form in which the entire sphere (corresponding to a solid angle of 4π) of the nanoparticle 10 is covered with the shell-like ligand 20. In the ink composition 440 of this embodiment, the organic group 44a compatible with the polymerizable compound 50 contained in the medium is from the organic high silicon molecule portion 44, and does not include an organic group from the bond portion 30, which is different from the ink composition 400 of the sixth embodiment.

[0235] The shell ligand 20 of this modified embodiment has at least a portion coordinated to the nanoparticle 10, similar to the shell ligand 20 of the sixth embodiment. The shell ligand 20 in the ink composition 440 has a discontinuous portion (not shown) that does not cover a portion of the nanoparticle 10. The discontinuous portions (not shown) that do not cover part of the nanoparticle 10 include a mesh of holes formed by overlapping linear organosilicon polymer portions 44 that extend in different directions along the shell of the shell ligand 20.

[0236] In the ink composition 440 according to this embodiment, the organic group 44a of the shell-shaped ligand 20 ensures compatibility with the polymerizable compound 50 in the medium, and the nanoparticles 10 protected by the shell-shaped ligand 20 maintain a stable dispersed state.

[0237] <Second Reference Form> 8(a) and (b) are diagrams showing the dispersion state of the ink composition 900 according to the second reference embodiment immediately after preparation (a) and after 12 hours (b). The nanoparticles 10 corresponding to the quantum dots QD of the ink composition 900 according to the reference embodiment have a betaine structure 30b, but do not have a shell ligand 20, and only non-shell ligands 60 having a linear or branched skeleton are coordinated. Only the non-shell ligands 60 extending substantially radially from the surface of the nanoparticles 10 are coordinated to the surface of the nanoparticles 10.

[0238] Therefore, although the non-shell ligand 60 contained in the ink composition 900 has an organic group 60a, the bond related to the coordination with the nanoparticles 10 is not strong compared to the ink composition 400 according to the sixth embodiment. As a result, it is presumed that the ink composition 900 is easily attacked by the solvent 90 containing polar molecules, and the semiconductor composition of a part of the nanoparticles 10 may change. In addition, although the non-shell ligand 60 contains the organic group 60a, it is easily detached from the nanoparticles 10 in the ink composition 900, and compatibility with the polymerizable compound 50 in the medium cannot be sufficiently ensured, and it is presumed that aggregation of the nanoparticles 10 may occur as shown in FIG. 8(b). The aggregation of the nanoparticles 10 constitutes coarse secondary particles, which is considered to be a factor in reducing the quantum confinement effect and the quantum yield related to light emission.

[0239] <Eighth embodiment> FIG. 8(a) is a diagram showing the dispersion state of an ink composition 400 according to the eighth embodiment.

[0240] The ink composition 400 increases in viscosity and hardens due to polymerization of the polymerizable compound contained therein. Therefore, the ink composition 400 in Fig. 8(a) corresponding to the stage before curing is in the form of an ink having fluidity, and may be referred to as the ink composition 400. Curing may be referred to as solidifying. The light-emitting material 200 includes the light-responsive material 100 and the polymerizable compound 50. The light-emitting material 200 is in a state in which the light-responsive material 100 and the polymerizable compound 50 are co-dispersed in the solvent 90.

[0241] 6(a), the ink composition 400 of this embodiment has a configuration in which the shell ligand 20 substantially covers the entire sphere (corresponding to a solid angle of 4π) of the nanoparticle 10. The configuration in which the shell ligand 20 substantially covers the entire sphere of the nanoparticle 10 includes a configuration in which the organosilicon polymer portion 44 (polymer portion) has locally discontinuous portions 44u. In the ink composition 400 of this embodiment, the organic group 40a that is compatible with the polymerizable compound 50 contained in the medium is part of the structure contained in the organosilicon polymer portion 44.

[0242] The shell-like ligand 20 in this modified form has at least a portion that is coordinated to the nanoparticle 10. The shell-like ligand 20 in the ink composition 400 has discontinuous portions (not shown) that do not cover a portion of the nanoparticle 10. The discontinuous portions (not shown) that do not cover a portion of the nanoparticle 10 include mesh-like holes that are formed by overlapping linear organosilicon polymer portions 44 that extend in different directions along the shell of the shell-like ligand 20.

[0243] A modification of this embodiment also includes an embodiment in which an organic group is provided as a part of the structure of the binding portion. In such a modification (not shown), the organic group protrudes outward from the shell ligand through the mesh of the network structure formed by the polymer portion.

[0244] The ink composition 400 forms a film-like wavelength converting portion 526 by hardening the polymerizable compound 50 through polymerization.

[0245] <Ninth embodiment> FIG. 8(b) shows a cross-sectional structure of a display element 500 according to the ninth embodiment.

[0246] The display element 500 has a light-emitting layer 510, a dielectric multilayer film 517, and a wavelength conversion layer 520 stacked in a stacking direction D1. The downstream side in the stacking direction D1 corresponds to the side where a user who views an image drawn on the display element is positioned. The wavelength conversion layer 520 is separated from the wavelength conversion layers corresponding to adjacent elements by a black matrix BM that separates the pixels.

[0247] As described above, the ink composition 400 is cured together with the polymerizable compound 50 by carrying out a polymerization process such as a photopolymerization process. The ink composition 400 is cured to form the wavelength conversion layer 520 of the display element 500 that satisfies predetermined dimensions. In other words, the wavelength conversion layer 520 is a layer that is solidified by being cured together with the polymerizable compound 50.

[0248] The light emitting layer 510 corresponds to a light source that emits light L1 of a first wavelength λ1. The wavelength conversion layer 520 has an optical coupling surface 522 that is optically coupled to the light emitting layer 510 on the side of the light emitting layer 510, and has an extraction surface 524 on the opposite side of the light emitting layer 510 that is converted by the wavelength conversion layer 520 and extracts the secondary light L2.

[0249] The wavelength conversion layer 520 of this embodiment receives primary light L1 of wavelength λ1 propagating through the dielectric multilayer film 917. The dielectric multilayer film 517 provides the display element 500 with the spectral transmission characteristics of the primary light from the light emitting layer 510 and the spectral reflection characteristics of secondary light L2 of wavelength λ2 emitted in the wavelength conversion layer 520. The wavelength λ2 of the secondary light L2 is longer than the wavelength λ1 of the primary light L1.

[0250] The dielectric multilayer film 917 can be replaced with another optical member having optical transparency to the first wavelength λ1 emitted by the light emitting layer 510. In addition, another optical member (not shown) can be disposed in front of the extraction surface 524 (opposite side to the light emitting layer 510). EXAMPLES

[0251] Hereinafter, the present disclosure will be described in further detail with reference to a first group of examples (Examples 1-1 to 15), but the present disclosure is not limited thereto.

[0252] [Production of polymer compound a] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen inlet tube, 17.9 parts of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate, 82.1 parts of octadecyl methacrylate, 4.1 parts of azobisisobutyronitrile, and 900 parts of n-butanol were charged, and nitrogen bubbling was performed for 30 minutes. The resulting reaction mixture was heated at 65°C for 8 hours under a nitrogen atmosphere to complete the polymerization reaction. After cooling the reaction solution to room temperature, the solvent was distilled off under reduced pressure. The resulting residue was dissolved in chloroform and purified by dialysis using a dialysis membrane (Spectra / Por7 MWCO 1kDa manufactured by Spectrum Laboratories). After distilling off the solvent under reduced pressure, the polymer compound 1-a was obtained by drying at 50°C and reduced pressure of 0.1kPa or less.

[0253] The obtained polymer compound 1-a was analyzed by the above analytical method, and it was confirmed that the weight average molecular weight (Mw) was 11,800 and that the structural unit represented by formula (2) was contained in 21 mol% of all monomer units. Note that the polymer compound 1-a may be referred to as the intermediate raw material a or precursor a of the shell-shaped ligand 20 that is coordinated to the particle surface of the nanoparticles 1-10 dispersed in the solvent 90.

[0254] [Preparation of polymer compound 1-b] Polymer compound 1-b was produced in the same manner as in the production of polymer compound 1-a, except that 48.1 parts of octyl methacrylate was used instead of octadecyl methacrylate.

[0255] [Production of polymer compound 1-c] Polymer compound 1-c was produced in the same manner as in the production of polymer compound 1-a, except that 41.3 parts of hexyl methacrylate was used instead of octadecyl methacrylate.

[0256] [Preparation of polymer compound 1-d] Polymer compound 1-d was produced in the same manner as in the production of polymer compound 1-a, except that 34.5 parts of butyl methacrylate was used instead of octadecyl methacrylate.

[0257] [Preparation of Comparative Polymer Compound 1-e] Comparative polymer compound 1-e was produced in the same manner as polymer compound 1-a, except that 17.9 parts of 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate and 102.6 parts of octadecyl methacrylate were used instead of 82.1 parts of octadecyl methacrylate.

[0258] The composition ratios and weight average molecular weights (Mw) of the polymer compounds 1-a to 1-e produced as described above are shown in Table 1. In Table 1, X indicates the bonding site of the structural unit represented by formula (1) with the polymer main chain, and X' indicates the bonding site of the structural unit represented by formula (1) with the phosphate ester site. In addition, Y represents a bonding site with the phosphate moiety of the structural unit represented by formula (1), Y' represents a bonding site with the quaternary ammonium salt moiety of the structural unit represented by formula (1), and Z represents a bonding site with the polymer main chain of the structural unit represented by formula (6).

[0259] [Table 1]

[0260] [Production of polymer compound 1-f] A reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen inlet tube was prepared. 25.4 parts of 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid, 36.1 parts of hexyl methacrylate, 4.1 parts of azobisisobutyronitrile, and 900 parts of 2,2,2-trifluoroethanol were charged into the reaction vessel. Nitrogen bubbling was then performed for 30 minutes into the reaction vessel. The reaction mixture was heated at 78°C for 8 hours under a nitrogen atmosphere to complete the polymerization reaction. After the reaction solution was cooled to room temperature, the solvent was distilled off under reduced pressure. The resulting residue was dissolved in 2,2,2-trifluoroethanol and purified by dialysis using a dialysis membrane (Spectra / Por7 MWCO 1kDa manufactured by Spectrum Laboratories). After the solvent was distilled off under reduced pressure, the polymer compound 1-f was obtained by drying at 50°C and 0.1kPa or less under reduced pressure.

[0261] [Production of polymer compound 1-g] Except for using 22.8 parts of 2-[[2-(methacryloyloxy)ethyl]dimethylammonio]acetic acid and 33.5 parts of hexyl methacrylate instead of 3-[[2-(methacryloyloxy)ethyl]dimethylammonio]propane-1-sulfonic acid, polymer compound 1-g was produced in the same manner as polymer compound 1-n. The composition ratio and weight average molecular weight (Mw) of polymer compounds 1-f and 1-g produced as described above are shown in Table 2. In addition, X in Table 2 indicates the bonding site of the structural unit represented by formula (5) with the polymer main chain, and X' indicates the bonding site of the structural unit represented by formula (5) with the quaternary ammonium site. In addition, Y in Table 2 indicates the bonding site of the structural unit represented by formula (2) with the quaternary ammonium site, Y' indicates the bonding site of the structural unit represented by formula (5) with the Y-site, and Z indicates the bonding site of the structural unit represented by formula (6) with the polymer main chain.

[0262] [Table 2]

[0263] (Example 1-1) [Polymer compound 1 - Preparation of solution] (Toluene solution of polymer compound 1-a) In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 1 part of polymer compound 1-a and 99 parts of toluene were charged, and the temperature was raised to 110° C. and heated for 5 minutes. After confirming that polymer compound 1-a was completely dissolved, the mixture was cooled to room temperature to obtain a toluene solution of polymer compound 1-a.

[0264] [Production of nanoparticles 1-a] 10 parts of cesium carbonate, 27 parts of oleic acid, and 385 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 30 minutes. The mixture was further heated to 150°C under a dry nitrogen stream and held for 30 minutes to obtain a cation raw material liquid.

[0265] Separately, 10 parts of lead(II) bromide and 494 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 1 hour. 89 parts of oleic acid and 31 parts of oleylamine were added, and the mixture was degassed with a vacuum pump for 30 minutes. The nitrogen flow was then replaced and the liquid temperature was raised to 185°C.

[0266] 40 parts of the cation source liquid was added, and after 5 seconds, the mixture was cooled on ice. 2000 parts of ethyl acetate was added, and the mixture was centrifuged to remove the supernatant. The resulting residue was dispersed in toluene to adjust the solid concentration to 1% by weight, and a dispersion of photoresponsive nanoparticles 1-a having a perovskite crystal structure of CsPbBr3 was obtained.

[0267] [Preparation of Ink Composition 1-1] 500 parts of the dispersion of nanoparticles 1-a were placed in a container, and the solvent was removed under reduced pressure. 500 parts of a toluene solution of polymer compound 1-a were added thereto, and the mixture was stirred for 3 hours. After the solvent was removed under reduced pressure again, 100 parts of 3,3,5-trimethylcyclohexyl acrylate (TMCHA) and 5 parts of 1-hydroxycyclohexyl phenyl ketone (Omnirad184) were added to obtain ink composition 1-1.

[0268] (Examples 1-2 to 1-4) Ink compositions 1-2 to 1-4 were obtained in the same manner as in Example 1-1, except that polymer compounds 1-b to 1-d were used instead of polymer compound 1-a, respectively.

[0269] (Examples 1 to 5) Ink composition 1-5 was obtained in the same manner as in Example 1-3, except that tetrahydrofurfuryl acrylate (THFA) was used instead of TMCHA.

[0270] (Examples 1 to 6) An ink composition 1-6 was obtained in the same manner as in Example 1-3, except that 1,6-hexanediol diacrylate (HDDA) was used instead of TMCHA.

[0271] (Examples 1 to 7) Ink composition 1-7 was obtained in the same manner as in Example 1-3, except that cyclohexyl acrylate (CHA) was used instead of TMCHA.

[0272] (Examples 1 to 8) An ink composition 1-8 was obtained in the same manner as in Example 1-3, except that a mixture of 80 parts of THFA and 20 parts of HDDA was used instead of 100 parts of TMCHA.

[0273] (Examples 1 to 9) An ink composition 1-9 was obtained in the same manner as in Example 1-1, except that the polymer compound 1-f was used instead of the polymer compound 1-a.

[0274] (Examples 1 to 10) An ink composition 1-10 was obtained in the same manner as in Example 1-1, except that the polymer compound 1-g was used instead of the polymer compound 1-a.

[0275] (Examples 1 to 11) An ink composition 1-11 was obtained in the same manner as in Example 1-1, except that 250 parts of the toluene solution of polymer compound 1-a was used instead of 500 parts of the toluene solution of polymer compound 1-a, and THFA was used instead of TMCHA.

[0276] (Examples 1 to 12) An ink composition 1-12 was obtained in the same manner as in Example 1-1, except that 1000 parts of the toluene solution of polymer compound 1-a was used instead of 500 parts of the toluene solution of polymer compound 1-a, and THFA was used instead of TMCHA.

[0277] [Production of nanoparticles 1-b] A dispersion of nanoparticles 1-b having a perovskite crystal structure of CsPb(Br / I)3 was obtained in the same manner as nanoparticles 1-a, except that 3.2 parts of lead(II) bromide and 9.3 parts of lead(II) iodide were used instead of 10 parts of lead(II) bromide.

[0278] (Examples 1 to 13) Ink composition 1-13 was obtained in the same manner as in Example 1-1, except that the amount of the dispersion liquid of photoresponsive nanoparticles 1-a was changed to 250 parts instead of 500 parts, and the amount of the toluene solution of polymer compound 1-a was changed to 250 parts instead of 500 parts.

[0279] [Production of nanoparticles 1-c] A dispersion of nanoparticles 1-c having a perovskite crystal structure of CsPbI3 was obtained in the same manner as in the photoresponsive nanocrystal dispersion a, except that 12.5 parts of lead(II) iodide were used instead of 10 parts of lead(II) bromide.

[0280] (Examples 1-14) An ink composition 1-14 was obtained in the same manner as in Example 1-1, except that polymer compound 1-c was used instead of polymer compound 1-a, and nanoparticles 1-c were used instead of nanoparticles 1-a.

[0281] [Preparation of nanoparticles 1-d] First, a solution of methylamine acetate oleate was synthesized as follows. 40 parts of methylamine acetate and 1290 parts of oleic acid were mixed in a flask and degassed for 3 hours at room temperature using a vacuum pump. The liquid temperature was then raised to 120°C and degassed for 30 minutes to obtain a solution of methylamine acetate oleate.

[0282] Next, a solution of formamidine acetate oleate was synthesized as follows: 46 parts of formamidine acetate and 1290 parts of oleic acid were mixed in a flask, and the mixture was degassed for 3 hours at room temperature using a vacuum pump. The mixture was then heated to 120°C and degassed for 30 minutes to obtain a solution of formamidine acetate oleate.

[0283] Separately, 10 parts of lead bromide, 129 parts of oleic acid, 59 parts of oleylamine, and 572 parts of octadecene were placed in a flask, and the liquid temperature was set to 160°C and degassed for 100 minutes using a vacuum pump. 16 parts of the above methylamine acetate oleate solution and 77 parts of the above formamidine acetate oleate solution were mixed and added to the flask all at once. 10 seconds after the addition, the flask was cooled on ice. The ice-cooled solution was centrifuged and the supernatant was removed. The resulting residue was dispersed in hexane and further centrifuged to remove the precipitate. The solid content was adjusted to 1% by weight to obtain a photoresponsive nanocrystal dispersion d having a perovskite-type crystal structure of (MA / FA)PbBr3.

[0284] (Examples 1 to 15) An ink composition 1-15 was obtained in the same manner as in Example 1-1, except that polymer compound 1-c was used instead of polymer compound 1-a, and nanoparticles 1-d were used instead of nanoparticles 1-a.

[0285] (Comparative Example 1-1) An ink composition 1-16 was obtained in the same manner as in Example 1-1, except that 500 parts of toluene was used instead of 500 parts of the toluene solution of polymer compound 1-a.

[0286] (Comparative Example 1-2) An ink composition 1-17 was obtained in the same manner as in Example 1-1, except that the polymer compound 1-e was used instead of the polymer compound 1-a.

[0287] (Comparative Example 1-3) Ink composition 1-18 was obtained in the same manner as in Comparative Example 1-1, except that THFA was used instead of TMCHA.

[0288] (Comparative Examples 1-4) Ink composition 1-19 was obtained in the same manner as in Example 1-1, except that 100 parts of a toluene solution of octadecyldimethyl(3-sulfopropyl)ammonium hydroxide inner salt (ligand a, manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 500 parts of the toluene solution of polymer compound 1-a.

[0289] For ink compositions 1-1 to 19, Table 3 shows the type and concentration of nanoparticles 1- and the type and concentration of polymer compound 1-.

[0290] [Table 3]

[0291] The abbreviations in Table 3 are as follows: TMCHA: 3,3,5-trimethylcyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) HDDA: 1,6-hexanediol diacrylate (Osaka Organic Chemical Industry Co., Ltd.) THFA: Tetrahydrofurfuryl acrylate (Osaka Organic Chemical Industry Co., Ltd.) CHA: Cyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.)

[0292] (Evaluation of Ink Composition 1-) The particle size distribution and absolute luminescence quantum yield (hereinafter, PLQY) of the obtained ink compositions 1-1 to 16 were measured and used as an initial evaluation. Next, the ink composition 1- composition was left to stand for 14 days at a humidity of 70% RH and 25°C using a constant temperature and humidity chamber, and then the particle size distribution and PLQY were measured and used as an evaluation after aging. The particle size distribution was measured using a Zetasizer Nano ZS (manufactured by Malvern Instruments), and the arithmetic mean diameter (number basis) of the particle size distribution was used as the measured value. The evaluation criteria were as follows.

[0293] <Initial particle size evaluation criteria> A: Initial particle size less than 20 nm B: Initial particle size 20 nm or more and less than 50 nm C: Initial particle size 50 nm or more and less than 80 nm D: Initial particle size 80nm or more

[0294] <Evaluation criteria for particle size change> A: Particle size change less than 2 times B: Particle size change 2x or more but less than 3x C: Particle size change 3 times or more but less than 4 times D: Particle size change 4 times or more

[0295] Here, the change in particle size is defined as particle size after aging / initial particle size.

[0296] PLQY is the number of photons of fluorescent emission when the number of excitation photons absorbed by the photoresponsive nanocrystal is taken as 1. The measurement conditions and evaluation criteria are shown below.

[0297] <Measurement conditions> Measurement equipment: Absolute PL quantum yield measurement equipment C9920-03 (Hamamatsu Photonics) Excitation light wavelength: 460 nm Excitation light integration range: Excitation light wavelength ±10nm Emission integral range: (excitation light wavelength + 20) nm to 770 nm

[0298] <Evaluation criteria> A: Absolute value of PLQY change rate is less than 10% B: Absolute value of PLQY change rate is 10% or more and less than 25% C: Absolute value of PLQY change rate is 25% or more and less than 40% D: Absolute value of PLQY change rate is 40% or more The results are shown in Table 4.

[0299] [Table 4]

[0300] According to Table 4, the ink compositions 1-1 to 15 according to Examples 1-1 to 15 of the present invention have small initial particle size, small particle size change, and small PLQY change for a number of media. This is presumably because the shell ligand 20 having the betaine structure 30b at the bonding portion 30 is tightly coordinated to the nanoparticle 1-10, and the organic group 30a or 40a is compatible with the polymerizable compound 50, so that the light-responsive material 100 exhibits high dispersion stability.

[0301] On the other hand, the ink compositions 1-17 to 19 not including the shell ligand 20 as in Comparative Examples 1-1 to 1-4 may have small initial particle sizes, but the particle sizes increased over time and the PLQY decreased. It is presumed that the ink compositions 1-17 to 19 are composed of coarse secondary particles.

[0302] The IR absorption spectrum of Ink Composition 1-9 was measured, and a peak at 1031 cm was observed, which is due to the S=O symmetric vibration of the sulfobetaine group. -1 A peak was observed at 100 nm, confirming the coordination of the shell-like ligand 20 with the nanoparticle 10.

[0303] Hereinafter, the present disclosure will be described in further detail with reference to a second group of examples (Examples 2-14 to 2-28), but the present disclosure is not limited thereto.

[0304] [Preparation of polymer compound 2-a] In a reaction vessel equipped with a cooling tube, a stirrer, a thermometer, and a nitrogen inlet tube, 15.8 parts of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (80% aqueous solution), 82.1 parts of octadecyl methacrylate, 4.1 parts of azobisisobutyronitrile, and 900 parts of n-butanol were charged, and nitrogen bubbling was performed for 30 minutes. The resulting reaction mixture was heated at 65°C for 8 hours under a nitrogen atmosphere to complete the polymerization reaction. After cooling the reaction solution to room temperature, the solvent was distilled off under reduced pressure. The resulting residue was dissolved in chloroform and purified by dialysis using a dialysis membrane (Spectra / Por7 MWCO 1kDa manufactured by Spectrum Laboratories). After distilling off the solvent under reduced pressure, the polymer compound 2-a was obtained by drying at 50°C and 0.1kPa or less under reduced pressure.

[0305] The obtained polymer compound 2-a was analyzed by the above-mentioned analytical method, and it was confirmed that the weight average molecular weight (Mw) was 21,000 and that the monomer containing the partial structure represented by formula (1) was contained in an amount of 21 mol% of all monomer units.

[0306] [Preparation of polymer compound 2-b] A solution of 1.3 parts of sodium bromide dissolved in 2.7 parts of water was slowly added to a solution of 5 parts of polymer compound 2-a dissolved in 95 parts of tetrahydrofuran, and the mixture was stirred at room temperature for 2 hours. The resulting solution was reprecipitated with water, washed with methanol, and then vacuum-dried at 50°C for 2 hours to produce polymer compound 2-b.

[0307] [Production of polymer compound 2-c] Polymer compound 2-c was produced in the same manner as polymer compound 2-b, except that a solution of 1.9 parts of sodium iodide in 2.0 parts of water was used instead of a solution of 1.3 parts of sodium bromide in 2.7 parts of water.

[0308] [Preparation of polymer compound 2-d] Polymer compound 2-d was produced in the same manner as polymer compound 2-b, except that a solution of 0.39 parts of sodium bromide and 1.3 parts of sodium iodide in 2.7 parts of water was used instead of a solution of 1.3 parts of sodium bromide in 2.7 parts of water.

[0309] [Production of polymer compound 2-e] [2-(methacryloyloxy)ethyl]trimethylammonium chloride (80% aqueous solution) 15.8 parts, octadecyl methacrylate 82.1 parts, instead of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (80% aqueous solution) 29.3 parts, octadecyl methacrylate 63.4 parts were used, except that polymer compound 2-5 parts obtained in the same manner as polymer compound 2-a was dissolved in tetrahydrofuran 95 parts, and a solution in which 1.9 parts of sodium iodide was dissolved in water 2.0 parts was slowly added and stirred at room temperature for 2 hours. The obtained solution was reprecipitated with water, washed with methanol, and then vacuum dried at 50 ° C for 2 hours to produce polymer compound 2-e.

[0310] [Production of polymer compound 2-f] Polymer compound 2-af was obtained in the same manner as polymer compound 2-a, except that 48.1 parts of octyl methacrylate was used instead of 82.1 parts of octadecyl methacrylate. A solution of 1.9 parts of sodium iodide dissolved in 2.0 parts of water was slowly added to a solution of 5 parts of the obtained polymer compound 2-af dissolved in 95 parts of tetrahydrofuran, and stirred at room temperature for 2 hours. The obtained solution was reprecipitated with water, washed with methanol, and then vacuum dried at 50 ° C for 2 hours to produce polymer compound 2-f.

[0311] [Production of polymer compound 2-g] Polymer compound 2-ag was obtained in the same manner as polymer compound 2-a, except that 41.3 parts of hexyl methacrylate were used instead of 82.1 parts of octadecyl methacrylate. A solution of 1.9 parts of sodium iodide dissolved in 2.0 parts of water was slowly added to a solution of 5 parts of polymer compound 2-ag thus obtained in 95 parts of tetrahydrofuran, and the mixture was stirred at room temperature for 2 hours. The obtained solution was reprecipitated with water, washed with methanol, and then vacuum dried at 50°C for 2 hours to produce polymer compound 2-g.

[0312] [Preparation of polymer compound 2-h] Polymer compound 2-ah was obtained in the same manner as polymer compound 2-a, except that 34.5 parts of butyl methacrylate was used instead of 82.1 parts of octadecyl methacrylate. A solution of 1.9 parts of sodium iodide dissolved in 2.0 parts of water was slowly added to a solution of 5 parts of polymer compound 2-ah thus obtained in 95 parts of tetrahydrofuran, and the mixture was stirred at room temperature for 2 hours. The obtained solution was reprecipitated with water, washed with methanol, and then vacuum dried at 50°C for 2 hours to produce polymer compound 2-h.

[0313] [Preparation of Comparative Polymer Compound 2-i] Comparative polymer compound 2-i was produced in the same manner as polymer compound 2-a, except that 108 parts of octadecyl methacrylate were used instead of 15.8 parts of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (80% aqueous solution) and 82.1 parts of octadecyl methacrylate.

[0314] The composition ratios and weight average molecular weights (Mw) of the polymer compounds 2-a to 2-i produced as described above are shown in Table 5. In Table 5, a indicates the bonding site with the carbon atom to which R12 in formula (5) is bonded, b indicates the bonding site with the quaternary ammonium moiety, and c indicates the bonding site with R 16 The bond sites with the carbon atom to which each is bonded are shown.

[0315] [Table 5]

[0316] (Example 2-1) [Preparation of polymer compound 2-a to 2-i solutions] (Toluene solution of polymer compound 2-a) In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 0.5 parts of polymer compound 2-a and 99.5 parts of toluene were charged, and the temperature was raised to 110° C. and heated for 5 minutes. After confirming that polymer compound 2-a was completely dissolved, the mixture was cooled to room temperature to obtain a toluene solution of polymer compound 2-a.

[0317] [Preparation of nanoparticle dispersion 2-a] 10 parts of cesium carbonate, 27 parts of oleic acid, and 385 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 30 minutes. The mixture was further heated to 150°C under a dry nitrogen stream and held for 30 minutes to obtain a cation raw material liquid.

[0318] Separately, 10 parts of lead(II) bromide and 494 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 1 hour. 89 parts of oleic acid and 31 parts of oleylamine were added, and the mixture was degassed with a vacuum pump for 30 minutes. The nitrogen flow was then replaced and the liquid temperature was raised to 185°C.

[0319] 40 parts of the cation raw material solution was added, and after 5 seconds, the mixture was cooled on ice. 2000 parts of ethyl acetate was added, and the mixture was centrifuged to remove the supernatant. The resulting residue was dispersed in toluene to adjust the solid content to 1% by weight, and nanoparticle dispersion 2-a having a perovskite crystal structure of CsPbBr3 was obtained. The peak wavelength was 512 nm.

[0320] [Preparation of photoresponsive material 2-1] A dry nitrogen stream was blown onto 10 parts of the nanoparticle dispersion 2-a to remove the solvent, and 10 parts of the toluene solution of the polymer compound 2-a was added thereto and stirred for 3 hours to obtain a photoresponsive material 2-1.

[0321] (Example 2-2) A photoresponsive material 2-2 was obtained in the same manner as in Example 2-1 above, except that polymer compound 2-b was used instead of polymer compound 2-a.

[0322] (Example 2-3) A photoresponsive material 2-3 was obtained in the same manner as in Example 2-1 above, except that 1 part of polymer compound 2-b and 99 parts of toluene were used instead of 0.5 part of polymer compound 2-a and 99.5 parts of toluene.

[0323] (Examples 2-4) A photoresponsive material 2-4 was obtained in the same manner as in Example 2-1 above, except that 1 part of polymer compound 2-c and 99 parts of toluene were used instead of 0.5 part of polymer compound 2-a and 99.5 parts of toluene.

[0324] [Preparation of nanoparticle dispersion 2-b] CsPb(Br 0.3 / I 0.7 ) Nanoparticle dispersion liquid 2-b having a perovskite type crystal structure of 3 was obtained. The peak wavelength was 640 nm.

[0325] (Examples 2-5) A photoresponsive material 2-5 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of nanoparticle dispersion liquid 2-a.

[0326] (Examples 2-6) A photoresponsive material 2-6 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-b was used instead of the polymer compound 2-a.

[0327] (Examples 2-7) A photoresponsive material 2-7 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-c was used instead of the polymer compound 2-a.

[0328] (Examples 2-8) Photoresponsive material 2-8 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of nanoparticle dispersion 2-a, and 1 part of polymer compound 2-c and 99 parts of toluene were used instead of 0.5 parts of polymer compound 2-a and 99.5 parts of toluene.

[0329] (Examples 2-9) A photoresponsive material 2-9 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of the nanoparticle dispersion liquid 2-a, and polymer compound 2-d was used instead of the polymer compound 2-a.

[0330] (Examples 2-10) A photoresponsive material 2-10 was obtained in the same manner as in Example 2-1 above, except that nanoparticles b were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-e was used instead of the polymer compound 2-a.

[0331] [Preparation of nanoparticle dispersion 2-c] Nanoparticle dispersion 2-c having a perovskite crystal structure of CsPbI3 was obtained in the same manner as nanoparticle dispersion 2-a, except that 12.5 parts of lead(II) iodide were used instead of 10 parts of lead(II) bromide. The peak wavelength was 690 nm.

[0332] (Example 2-11) A light-responsive material 2-11 was obtained in the same manner as in Example 2-1 above, except that nanoparticles c were used instead of the nanoparticle dispersion liquid 2-a.

[0333] (Example 2-12) A photoresponsive material 2-12 was obtained in the same manner as in Example 2-1 above, except that nanoparticles c were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-b was used instead of the polymer compound 2-a.

[0334] (Example 2-13) A photoresponsive material 2-13 was obtained in the same manner as in Example 2-1 above, except that nanoparticles c were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-c was used instead of the polymer compound 2-a.

[0335] (Comparative Example 2-1) A photoresponsive material 2-14 was obtained in the same manner as in Example 2-1 above, except that 0.5 parts of polymer compound 2-a and 100 parts of toluene were used instead of 99.5 parts of toluene.

[0336] (Comparative Example 2-2) A photoresponsive material 2-15 was obtained in the same manner as in Example 2-1 above, except that didodecyldimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the polymer compound 2-a.

[0337] (Comparative Example 2-3) A photoresponsive material 2-16 was obtained in the same manner as in Example 2-1 above, except that nanoparticles c were used instead of the nanoparticle dispersion 2-a, and polymer compound 2-i was used instead of the polymer compound 2-a.

[0338] For the photoresponsive materials 2-1 to 21, the type and concentration of nanoparticles, and the type and concentration of the added polymer compound 2- or ligand are shown in Table 6.

[0339] [Table 6]

[0340] The abbreviations in Table 6 are as follows: DDAB: Didodecyldimethylammonium bromide (Tokyo Chemical Industry Co., Ltd.)

[0341] <Evaluation of photoresponsive materials 2-1 to 16> The obtained light-responsive materials 2-1 to 16 were evaluated as follows. The results are shown in Table 7.

[0342] [Evaluation of luminescence characteristics] For each photoresponsive material 2-, the emission peak wavelength, full width at half maximum, and absolute emission quantum yield (PLQY) were measured immediately after preparation and 30 minutes after adding 50 volume% of 2-propanol (IPA). After adding IPA, the samples were stored in a dark room to prevent the promotion of detachment of non-shell ligands and the inhibition of coordination of shell ligands due to light.

[0343] The emission peak wavelength and full width at half maximum are the values of the emission spectrum that form the basis for calculating the PLQY. The PLQY is the number of photons of fluorescence emission when the number of excited photons absorbed by the luminescent nanocrystal is set to 1. Each photosensitive material 2- was diluted with toluene so that the light absorption rate at the excitation wavelength was between 0.2 and 0.3, and then the measurement was performed. The measurement conditions and evaluation criteria are shown below. The full width at half maximum may be paraphrased as the half width.

[0344] <Measurement Conditions> Measuring device: Absolute PL quantum yield measuring device C9920-03 (manufactured by Hamamatsu Photonics) Excitation light wavelength: 460 nm Excitation light integration range: Excitation light wavelength ±10 nm Emission light integration range: (Excitation light wavelength + 20) nm to 770 nm

[0345] <Evaluation Criteria for PLQY Change> A: Absolute value of PLQY change rate less than 20% B: Absolute value of PLQY change rate 20% or more and less than 40% C: Absolute value of PLQY change rate 40% or more and less than 80% D: Absolute value of PLQY change rate 80% or more

[0346]

Table 7

[0347] According to Table 7, the photosensitive materials 2-1 to 13 according to Examples 2-1 to 13 exhibited a high PLQY of 63% or more immediately after preparation, and they could be maintained even when IPA, a polar solvent, was added. This is presumably because in the photosensitive materials 2-1 to 13 according to Examples 2-1 to 13, the nanoparticles 10 are protected by the shell-like ligand 20 having a specific structure, ensuring the stability of the nanoparticles 10.

[0348] On the other hand, the photosensitive materials 2- that do not contain the shell-like ligand 20, such as Comparative Examples 2-1 to 3, may have a low PLQY immediately after preparation and may be greatly deactivated over time.

[0349] (Examples 2-14) [Polymer compound 2 - Preparation of solution] (Toluene solution of polymer compound 2-b) In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 1 part of polymer compound 2-b and 99 parts of toluene were charged, and the temperature was raised to 110° C. and heated for 5 minutes. After confirming that polymer compound 2-a was completely dissolved, the mixture was cooled to room temperature to obtain a toluene solution of polymer compound 2-b.

[0350] [Preparation of Ink Composition 2-1] A dry nitrogen stream was blown onto 500 parts of nanoparticle dispersion 2-a to remove the solvent. 500 parts of the toluene solution of polymer compound 2-b was added thereto and stirred for 3 hours. A dry nitrogen stream was blown onto the stirred solution again to remove the solvent. After that, it was dried, and 100 parts of 3,3,5-trimethylcyclohexyl acrylate (TMCHA) and 5 parts of 1-hydroxycyclohexyl phenyl ketone (Omnirad184) were added as polymerizable compounds to the solid components of the solution and stirred thoroughly to obtain ink composition 2-1.

[0351] (Example 2-15) Ink composition 2-2 was obtained in the same manner as in Example 2-14, except that tetrahydrofurfuryl acrylate (THFA) was used instead of TMCHA.

[0352] (Example 2-16) Ink composition 2-3 was obtained in the same manner as in Example 2-14, except that 1,6-hexanediol diacrylate (HDDA) was used instead of TMCHA.

[0353] (Example 2-17) An ink composition 2-4 was obtained in the same manner as in Example 2-14, except that the nanoparticle dispersion 2-b was used instead of the nanoparticle dispersion 2-a, and the polymer compound 2-c was used instead of the polymer compound 2-b.

[0354] (Example 2-18) Ink composition 2-5 was obtained in the same manner as in Example 2-15, except that tetrahydrofurfuryl acrylate (THFA) was used instead of TMCHA.

[0355] (Example 2-19) Ink composition 2-6 was obtained in the same manner as in Example 2-16, except that 1,6-hexanediol diacrylate (HDDA) was used instead of TMCHA.

[0356] (Example 2-20) An ink composition 2-7 was obtained in the same manner as in Example 2-14, except that the nanoparticle dispersion 2-c was used instead of the nanoparticle dispersion 2-a, and the polymer compound 2-c was used instead of the polymer compound 2-b.

[0357] (Example 2-21) Ink composition 2-8 was obtained in the same manner as in Example 2-20, except that tetrahydrofurfuryl acrylate (THFA) was used instead of TMCHA.

[0358] (Example 2-22) Ink composition 2-9 was obtained in the same manner as in Example 2-20, except that 1,6-hexanediol diacrylate (HDDA) was used instead of TMCHA.

[0359] (Example 2-23) An ink composition 2-10 was obtained in the same manner as in Example 2-14, except that the nanoparticle dispersion 2-c was used instead of the nanoparticle dispersion 2-a, and the polymer compound 2-a was used instead of the polymer compound 2-b.

[0360] (Example 2-24) Ink composition 2-11 was obtained in the same manner as in Example 2-17, except that cyclohexyl acrylate (CHA) was used instead of TMCHA.

[0361] (Example 2-25) An ink composition 2-12 was obtained in the same manner as in Example 2-17, except that 80 parts of TMCHA and 20 parts of HDDA were used instead of 100 parts of TMCHA.

[0362] (Example 2-26) An ink composition 2-13 was obtained in the same manner as in Example 2-17, except that polymer compound 2-f was used instead of polymer compound 2-c.

[0363] (Example 2-27) An ink composition 2-14 was obtained in the same manner as in Example 2-17, except that polymer compound 2-g was used instead of polymer compound 2-c.

[0364] (Example 2-28) An ink composition 2-15 was obtained in the same manner as in Example 2-17, except that polymer compound 2-h was used instead of polymer compound 2-c.

[0365] (Comparative Example 2-4) An ink composition 2-16 was obtained in the same manner as in Example 2-17, except that toluene was used instead of the polymer compound 2-c.

[0366] (Comparative Example 2-5) An ink composition 2-17 was obtained in the same manner as in Example 2-17, except that didodecyldimethylammonium bromide (DDAB) was used instead of the polymer compound 2-c.

[0367] (Comparative Example 2-6) An ink composition 2-18 was obtained in the same manner as in Example 2-17, except that polymer compound 2-i was used instead of polymer compound 2-c.

[0368] [Table 8]

[0369] The abbreviations in Table 8 are as follows: TMCHA: 3,3,5-trimethylcyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) HDDA: 1,6-hexanediol diacrylate (Osaka Organic Chemical Industry Co., Ltd.) THFA: Tetrahydrofurfuryl acrylate (Osaka Organic Chemical Industry Co., Ltd.) CHA: Cyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) DDAB: Didodecyldimethylammonium bromide (Tokyo Chemical Industry Co., Ltd.)

[0370] [Characteristics evaluation] The particle size distribution and absolute luminescence quantum yield (hereinafter, PLQY) of the obtained ink compositions 2-1 to 16 were measured and used as an initial evaluation. Next, the ink composition 2- composition was left to stand for 14 days at a humidity of 70% RH and 25°C using a constant temperature and humidity chamber, and then the particle size distribution and PLQY were measured and used as an evaluation after aging. The particle size distribution was measured using a Zetasizer Nano ZS (manufactured by Malvern Instruments), and the arithmetic mean diameter (number basis) of the particle size distribution was used as the measured value. The evaluation criteria were as follows.

[0371] <Initial particle size evaluation criteria> A: Initial particle size less than 30 nm B: Initial particle size 30 nm or more and less than 60 nm C: Initial particle size 60 nm or more and less than 90 nm D: Initial particle size 90nm or more

[0372] <Evaluation criteria for particle size change> A: Particle size change less than 2 times B: Particle size change 2x or more but less than 3x C: Particle size change 3 times or more but less than 4 times D: Particle size change 4 times or more

[0373] Here, the change in particle size is defined as particle size after aging / initial particle size.

[0374] PLQY is the number of photons emitted by fluorescence when the number of excitation photons absorbed by the luminescent nanocrystal is taken as 1. Each photoresponsive material 2- was diluted with toluene and then measured so that the optical absorptance at the excitation light wavelength was between 0.2 and 0.3. The measurement conditions and evaluation criteria are shown below.

[0375] <Measurement conditions> Measuring device: Absolute PL quantum yield measuring device C9920-03 (manufactured by Hamamatsu Photonics) Excitation light wavelength: 460 nm Excitation light integration range: Excitation light wavelength ±10 nm Emission light integration range: (Excitation light wavelength + 20) nm to 770 nm

[0376] <PLQY evaluation criteria> A: Absolute value of PLQY change rate less than 10% B: Absolute value of PLQY change rate 10% or more and less than 25% C: Absolute value of PLQY change rate 25% or more and less than 40% D: Absolute value of PLQY change rate 40% or more

[0377]

Table 9

[0378] According to Table 9, the ink compositions 2-1 to 15 according to Examples 2-14 to 28 of the present invention have a small initial particle size with respect to a plurality of media, and also have small particle size changes and PLQY changes over time. This is presumably because the shell-like ligand 20 having the quaternary ammonium salt 30b in the bonding portion 30 is strongly coordinated to the nanoparticles 10, and the alkyl chain 30a or 40a is compatible with the polymerizable compound 50, thereby exhibiting the dispersion stability of the photoreactive material 100.

[0379] On the other hand, although the ink compositions 2-16 to 18 that do not contain the shell-like ligand 20 as in Comparative Examples 2-4 to 6 may have a small initial particle size and PLQY change, it is presumed that in all cases, the particle size increases over time and they form coarsened secondary particles.

[0380] Hereinafter, the present disclosure will be described in more detail by the third example group (Examples 3-1 to 15), but the present disclosure is not limited thereto.

[0381] [Production of sulfobetaine silane compound] 5 g of [3-(N,N-dimethylamino)propyl]trimethoxysilane and 3 g of 1,3-propane sultone were dissolved in 25 ml of acetone and stirred for 6 hours under a nitrogen atmosphere. After washing with acetone, the mixture was filtered to obtain 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)propane-1-sulfonate as a sulfobetaine silane compound.

[0382] [Production of carboxybetaine silane compounds] 5g of (N,N-dimethylaminopropyl)trimethoxysilane was mixed with 7g of ethyl-4-bromobutyrate in 20ml of acetonitrile. After reacting under reflux for 72 hours, 60ml of ether was added and the unreacted reactants were removed with a rotary evaporator to obtain a carboxybetaine silane compound.

[0383] (Example 3-1) [Preparation of sulfobetaine silane compound solution] (Toluene solution of sulfobetaine silane compound) In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 2.5 parts of sulfobetaine silane compound and 97.5 parts of toluene were charged, and the temperature was raised to 110° C. and heated for 30 minutes. After confirming that the sulfobetaine silane compound had dissolved, the mixture was cooled to room temperature to obtain a toluene solution of the sulfobetaine silane compound.

[0384] [Production of functionalized sulfobetaine silane compounds] To 97.5 parts of a toluene solution of a sulfobetaine silane compound, 2.5 parts of trimethoxy(propyl)silane was gradually added over 1 hour, and the mixture was stirred for an additional 30 minutes and then cooled to room temperature to obtain a toluene solution of a sulfobetaine silane compound in which a propyl group had been introduced as a functional group (hereinafter, functionalized sulfobetaine silane compound).

[0385] [Preparation of photoresponsive nanoparticles 3-a] 10 parts of cesium carbonate, 27 parts of oleic acid, and 385 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 30 minutes. The mixture was further heated to 150°C under a dry nitrogen stream and held for 30 minutes to obtain a cation raw material liquid.

[0386] Separately, 10 parts of lead(II) bromide and 494 parts of 1-octadecene were placed in a flask, heated to 120°C, and degassed with a vacuum pump for 1 hour. 89 parts of oleic acid and 31 parts of oleylamine were added, and the mixture was degassed with a vacuum pump for 30 minutes. The nitrogen flow was then replaced and the liquid temperature was raised to 185°C.

[0387] 40 parts of the cation raw material solution was added, and after 5 seconds, the mixture was cooled on ice. 2000 parts of ethyl acetate was added, and the mixture was centrifuged to remove the supernatant. The resulting residue was dispersed in toluene to adjust the solid concentration to 1% by weight, and photoresponsive nanoparticles 3-dispersion solution a having a perovskite crystal structure of CsPbBr3 was obtained.

[0388] [Preparation of Ink Composition 3-1] A dry nitrogen stream was blown onto 500 parts of the photoresponsive nanoparticle 3-dispersion liquid a to remove the solvent. 500 parts of a toluene solution of a functionalized sulfobetaine silane compound was added thereto and stirred for 3 hours. After again blowing a dry nitrogen stream to remove the solvent, 50 parts of toluene, 100 parts of 3,3,5-trimethylcyclohexyl acrylate (TMCHA), and 5 parts of 1-hydroxycyclohexyl phenyl ketone (Omnirad184) were added to obtain ink composition 3-1.

[0389] (Example 3-2) An ink composition 3-2 was obtained in the same manner as in Example 3-1, except that hexyltrimethoxysilane was used instead of trimethoxy(propyl)silane.

[0390] (Example 3-3) Ink composition 3-3 was obtained in the same manner as in Example 3-1, except that 3-(trimethoxysilyl)propyl methacrylate was used instead of trimethoxy(propyl)silane.

[0391] (Examples 3-4) Ink composition 3-4 was obtained in the same manner as in Example 3-1, except that 3-(trimethoxysilyl)propyl acrylate was used instead of trimethoxy(propyl)silane.

[0392] (Examples 3-5) Ink composition 3-5 was obtained in the same manner as in Example 3-1, except that a toluene solution of a sulfobetaine silane compound without a functional group was used instead of a toluene solution of a functionalized sulfobetaine silane compound. In this case, no functional group was introduced by the additional compound, but the sulfobetaine silane compound (3-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)propane-1-sulfonate) molecules condensed with each other, and some of them became compounds with a propyl group as a functional group and a betaine structure at the terminal.

[0393] (Examples 3 to 6) An ink composition 3-6 was obtained in the same manner as in Example 3-2, except that tetrahydrofurfuryl acrylate (THFA) was used instead of TMCHA.

[0394] (Examples 3 to 7) Ink composition 3-7 was obtained in the same manner as in Example 3-2, except that 1,6-hexanediol diacrylate (HDDA) was used instead of TMCHA.

[0395] (Examples 3 to 8) Ink composition 3-8 was obtained in the same manner as in Example 3-2, except that cyclohexyl acrylate (CHA) was used instead of TMCHA.

[0396] (Examples 3 to 9) An ink composition 3-9 was obtained in the same manner as in Example 3-2, except that a mixture of 80 parts of THFA and 20 parts of HDDA was used instead of 100 parts of TMCHA.

[0397] (Examples 3-10) An ink composition 3-10 was obtained in the same manner as in Example 3-1, except that a carboxybetaine silane compound was used instead of the sulfobetaine silane compound.

[0398] (Examples 3-11) Ink composition 3-11 was obtained in the same manner as in Example 3-1, except that 1 part of hexyltrimethoxysilane was used in 99 parts of the toluene solution of sulfobetaine silane compound instead of 2.5 parts of trimethoxy(propyl)silane in 97.5 parts of the toluene solution of sulfobetaine silane compound.

[0399] (Examples 3-12) Ink composition 3-12 was obtained in the same manner as in Example 3-1, except that 5 parts of hexyltrimethoxysilane were used in 95 parts of the toluene solution of the sulfobetaine silane compound instead of 2.5 parts of trimethoxy(propyl)silane in 97.5 parts of the toluene solution of the sulfobetaine silane compound.

[0400] [Preparation of photoresponsive nanoparticles 3-dispersion b] Photoresponsive nanoparticles 3-Dispersion b having a perovskite crystal structure of CsPb(Br / I)3 was obtained in the same manner as in the preparation of luminescent nanocrystal dispersion a, except that 3.3 parts of lead(II) bromide and 9.3 parts of lead(II) iodide were used instead of 10 parts of lead(II) bromide.

[0401] (Examples 3-13) An ink composition 3-13 was obtained in the same manner as in Example 3-2, except that the photoresponsive nanoparticle 3-dispersion liquid b was used instead of the photoresponsive nanoparticle 3-dispersion liquid a.

[0402] [Photoresponsive nanoparticles 3 - Preparation of dispersion c] Photoresponsive nanoparticles 3-Dispersion c having a perovskite crystal structure of CsPbI3 was obtained in the same manner as in the luminescent nanocrystal dispersion a, except that 12.5 parts of lead(II) iodide were used instead of 10 parts of lead(II) bromide.

[0403] (Examples 3-14) An ink composition 3-14 was obtained in the same manner as in Example 3-2, except that the photoresponsive nanoparticle 3-dispersion liquid c was used instead of the photoresponsive nanoparticle 3-dispersion liquid a.

[0404] [Preparation of photoresponsive nanoparticles 3-dispersion d] First, a solution of methylamine acetate oleate was synthesized as follows. 40 parts of methylamine acetate and 1290 parts of oleic acid were mixed in a flask and degassed for 3 hours at room temperature using a vacuum pump. The liquid temperature was then raised to 120°C and degassed for 30 minutes to obtain a solution of methylamine acetate oleate.

[0405] Next, a solution of formamidine acetate oleate was synthesized as follows: 46 parts of formamidine acetate and 1290 parts of oleic acid were mixed in a flask, and the mixture was degassed for 3 hours at room temperature using a vacuum pump. The mixture was then heated to 120°C and degassed for 30 minutes to obtain a solution of formamidine acetate oleate.

[0406] Separately, 10 parts of lead bromide, 129 parts of oleic acid, 59 parts of oleylamine, and 572 parts of octadecene were placed in a flask, and the liquid temperature was set to 160°C and degassed for 100 minutes using a vacuum pump. 16 parts of the above methylamine acetate oleate solution and 77 parts of the above formamidine acetate oleate solution were mixed and added to the flask all at once. 10 seconds after the addition, the flask was cooled on ice. The ice-cooled solution was centrifuged and the supernatant was removed. The resulting residue was dispersed in hexane and further centrifuged to remove the precipitate. The solid content was adjusted to 1% by weight to obtain photoresponsive nanoparticles 3-dispersion d having a perovskite crystal structure of (MA / FA)PbBr3.

[0407] (Examples 3-15) An ink composition 3-15 was obtained in the same manner as in Example 3-2, except that the photoresponsive nanoparticle 3-dispersion liquid d was used instead of the photoresponsive nanoparticle 3-dispersion liquid a.

[0408] (Comparative Example 3-1) An ink composition 3-16 was obtained in the same manner as in Example 3-1, except that 500 parts of toluene was used instead of 500 parts of the toluene solution of the functionalized sulfobetaine silane compound.

[0409] (Comparative Example 3-2) Ink composition 3-17 was obtained in the same manner as in Comparative Example 3-1, except that THFA was used instead of TMCHA.

[0410] (Comparative Example 3-3) Ink composition 3-18 was obtained in the same manner as in Example 3-1, except that 100 parts of a toluene solution of octadecyldimethyl(3-sulfopropyl)ammonium hydroxide inner salt (betaine ligand, manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 500 parts of a toluene solution of a functionalized sulfobetaine silane compound.

[0411] For ink compositions 3-1 to 18, Table 10 shows the type and concentration of the photoresponsive nanoparticles 3-, the betaine silane compound, and the type and concentration of the added silane compound.

[0412] [Table 10]

[0413] The abbreviations in Table 10 are as follows: TMCHA: 3,3,5-trimethylcyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) HDDA: 1,6-hexanediol diacrylate (Osaka Organic Chemical Industry Co., Ltd.) THFA: Tetrahydrofurfuryl acrylate (Osaka Organic Chemical Industry Co., Ltd.) CHA: Cyclohexyl acrylate (Osaka Organic Chemical Industry Co., Ltd.)

[0414] <Ink composition 3-Evaluation of the composition> The particle size distribution of the obtained ink compositions 3-1 to 14 was measured and used as an initial evaluation. Next, the ink composition 3- composition was left to stand for 14 days at a humidity of 70% RH and 25°C in a constant temperature and humidity chamber, and then the particle size distribution was measured and used as an evaluation after aging. The particle size distribution was measured using a Zetasizer Nano ZS (manufactured by Malvern Instruments), and the arithmetic mean diameter (number basis) of the particle size distribution was used as the measured value. The evaluation criteria were as follows. Initial particle size A: Initial particle size less than 20 nm B: Initial particle size 20 nm or more and less than 50 nm C: Initial particle size 50 nm or more and less than 80 nm D: Initial particle size 80nm or more Particle size change A: Particle size change less than 2 times B: Particle size change 2x or more but less than 3x C: Particle size change 3 times or more but less than 4 times D: Particle size change 4 times or more

[0415] Here, the change in particle size is defined as particle size after aging / initial particle size.

[0416] The results are shown in Table 11.

[0417] [Table 11]

[0418] According to Table 11, ink composition 3- of the present invention has a small initial particle size and a small change in particle size, regardless of the type of medium.

[0419] By using a betaine silane compound with a functional group introduced as in the present invention, first, the betaine structure acts on the quantum dot surface, and it can be coordinated firmly and densely. Secondly, it is presumed that the organic group of the functional group linked to the main chain having the betaine structure is compatible with the polymerizable compound, resulting in high dispersion stability. It is considered that the same effect is also exhibited when a methacryl chain or an acrylic chain is introduced as a functional group.

[0420] On the other hand, ink compositions 3-16 to 3-18, which do not contain the specific polysiloxane compound of the present application as in Comparative Examples 3-1 to 3, sometimes had small initial particle sizes, but all of them showed a large change in particle size over time.

[0421] The inventions relating to the respective embodiments described in this specification include the following first to fifteenth inventions. The first invention relates to a nanoparticle having photoresponsiveness, a shell-like ligand including a plurality of binding parts each including an ionic structural unit and a polymer part that is bound to the nanoparticle at a plurality of sites via the plurality of binding parts, and a polymerizable compound that is polymerized upon receipt of energy. A second invention includes the ink composition according to the first invention, wherein the plurality of bonding portions include a zwitterionic structural skeleton. A third invention includes the ink composition according to the first or second invention, wherein the plurality of bonds include at least one structural skeleton of a betaine structure and a quaternary ammonium salt. A fourth invention includes the ink composition according to any one of the first to third inventions, wherein the multiple bonds include at least one structural unit of formulae (1) to (5) as a betaine structure.

[0422] [ka]

[0423] [ka]

[0424] [ka]

[0425] [ka]

[0426] [ka]

[0427] In the formulas (1) to (5), R1 to R5, R 12 ~R 15 each independently represents a hydrogen atom or an alkyl group, 11 represents an alkyl group or an aryl group, N represents a nitrogen atom, A1 to A7 represent linking groups, X - represents an anion, Y - is COO - group or SO3 - represents a group, and "*" represents a bond to the polymer moiety. A fifth invention includes the ink composition according to any one of the first to fourth inventions, wherein each of the plurality of bonds includes a structural unit represented by at least any one of formulas (1) to (3). A sixth invention includes the ink composition according to any one of the first to fifth inventions, wherein the polymer portion has a structural unit represented by at least any one of formulas (6) to (8).

[0428] [ka]

[0429] [ka]

[0430] [ka]

[0431] In the formulas (6) to (8), R 16 , R 18 each independently represents a hydrogen atom or an alkyl group; R 17 represents any one of an alkyl group, a carboxylic acid ester group, a carboxylic acid amide group, an alkoxy group, and an aryl group. 19represents an alkyl group, and B represents a bond to the bond. A seventh invention includes the ink composition according to any one of the first to sixth inventions, wherein the shell ligand has at least a portion coordinated to the nanoparticles. An eighth invention includes the ink composition according to any one of the first to seventh inventions, wherein the shell ligand has an organic group extending outward from the polymer portion. A ninth aspect of the present invention includes the ink composition according to the eighth aspect of the present invention, wherein the organic group is a part of an alkyl group contained in at least one of the bonding portion and the polymer portion. A tenth invention includes the ink composition according to the eighth or ninth invention, wherein the organic group is compatible with the polymerizable compound. An eleventh invention includes the ink composition according to any one of the first to tenth inventions, wherein the number average molecular weight of the shell ligand is 1,000 or more and 50,000 or less. A twelfth invention includes the ink composition according to any one of the first to eleventh inventions, wherein the nanoparticles have a perovskite crystal structure. A thirteenth invention includes a wavelength conversion member obtained by curing the ink composition according to any one of the first to twelfth inventions together with the polymerizable compound. A fourteenth aspect of the present invention relates to the thirteenth aspect of the present invention, wherein the wavelength conversion member includes a wavelength conversion layer having an optical coupling surface that is optically coupled to a light emitting layer that emits light of the first wavelength. A fifteenth aspect of the present invention includes the wavelength conversion layer according to the fourteenth aspect of the present invention, in which the nanoparticles emit light of a second wavelength that is longer than the light of the first wavelength received through the optical coupling surface. [Explanation of symbols]

[0432] 100 Photoresponsive materials 200, 220 Ink composition (photoresponsive composition) 10 Nanoparticles 20 Shell Ligands 30 Joint 30b Betaine structure 40, 44 Polymer part 30a and 40a organic groups 50 polymerizable compound

Claims

1. A photoresponsive material comprising: a luminescent nanoparticle; and a shell-like ligand including a plurality of binding moieties having a structural skeleton exhibiting zwitterionicity and a polymer moiety that binds to the nanoparticle at a plurality of sites via the plurality of binding moieties; a polymerizable compound that is polymerized upon receiving energy, The ink composition includes an ink having a shell-like ligand that extends outward from the polymer portion and includes an organic group that is compatible with the polymerizable compound.

2. The ink composition according to claim 1 , wherein the plurality of bonding moieties include at least one structural skeleton selected from the group consisting of a betaine structure and a quaternary ammonium salt.

3. 3. The ink composition according to claim 1, wherein the plurality of bonding moieties include at least one structural unit represented by formula (1) to formula (5). 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 5】 Here, in formulas (1) to (5), R １ ~R ５ , R １２ ~R １５ each independently represents either a hydrogen atom or an alkyl group, ６ ~R １１ represents either an alkyl group or an aryl group, N represents a nitrogen atom, A １ ~A ７ represents a linking group, and X － represents an anion, Y － is COO － group or SO ３ － represents a group, and "*" represents a bond to the polymer moiety.

4. 4. The ink composition according to claim 3, wherein each of the plurality of bonding moieties includes a structural unit represented by at least one of formulas (1) to (3).

5. 4. The ink composition according to claim 3, wherein the polymer portion has a structural unit represented by at least one of formulas (6) to (8). 【Transformation 6】 【Transformation 7】 【Transformation 8】 Here, in formulas (6) to (8), R １６ , R １８ each independently represents a hydrogen atom or an alkyl group; R １７ represents any one of an alkyl group, a carboxylic acid ester group, a carboxylic acid amide group, an alkoxy group, and an aryl group; R １９ represents an alkyl group, and B represents a bond to the bond.

6. The ink composition described in Claim 5, wherein the shell-like ligand comprises a copolymer of a bonding portion containing at least one of the structural units of formulas (1) to (3) and a polymer portion containing at least one of the structural units of formulas (6) to (8).

7. The ink composition according to claim 5, wherein the polymer portion has a structural unit represented by formula (6).

8. The ink composition according to claim 1 or 2, wherein the organic group is a part of an alkyl group contained in at least one of the bonding portion and the polymer portion.

9. The polymerizable compound constitutes a medium interposed between the photoresponsive materials, The ink composition according to claim 1 or 2, wherein the polymerizable compound is co-dispersed together with the photoresponsive material in the medium.

10. The ink composition described in claim 8, wherein the organic group includes an alkyl group having 4 or more carbon atoms.

11. The organic group is less polar than the bonding portion, the organic group is coordinated to a side of the medium containing the polymerizable compound relative to the polymer portion, The ink composition according to claim 1 or 2, wherein the binding moiety is coordinated to the nanoparticles via the polymer moiety.

12. The ink composition according to claim 10, wherein the medium comprises the polymerizable compound and a solvent.

13. The ink composition described in claim 1 or 2, wherein the polymerizable compound is a component that undergoes polymerization and hardens when exposed to energy.

14. 3. The ink composition according to claim 1, wherein the number average molecular weight of the shell-shaped ligand is 1,000 or more and 50,000 or less.

15. The ink composition according to claim 11, wherein the number average molecular weight of the shell-like ligand is 2,000 or more and 30,000 or less.

16. The ink composition according to claim 1 or 2, wherein the content of the shell-like ligand is 3 parts by mass or more and 500 parts by mass or less when the content of the nanoparticles is 100 parts by mass.

17. An ink composition described in claim 5, wherein the molar ratio of the structural unit represented by any one of formulas (1) to (3) to the structural unit represented by any one of formulas (6) to (8) is 6 / 94 or more and 45 / 55 or less.

18. 3. The ink composition according to claim 1, wherein the nanoparticles have a perovskite crystal structure.

19. The ink composition according to claim 18, wherein the perovskite crystal structure has an ABX 3 type crystal structure containing iodide anions at the X site.

20. A wavelength conversion member obtained by curing the ink composition according to claim 1 or 2 together with the polymerizable compound.

21. The wavelength conversion layer according to claim 20 , wherein the wavelength conversion member has an optical coupling surface that is optically coupled to a light emitting layer that emits light of the first wavelength.

22. 22. The wavelength conversion layer of claim 21, wherein the nanoparticles emit light at a second wavelength that is longer than the light at the first wavelength received through the optical coupling surface.

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