JP5257298B2 - Composite particles, colloidal crystals and methods for producing them - Google Patents

Description

  The present invention relates to composite particles, colloidal crystals, and methods for producing them.

  Poly (1,4-phenylene vinylene) (PPV) has been found to exhibit strong electroluminescence (electroluminescence, EL), and its future application to flat panel displays and the like is expected. PPV is a π-conjugated polymer composed of repeating units represented by the following formula.

  For example, Non-Patent Document 1 reports a method of supporting PPV in pores through a process of introducing PPV monomer into mesopores after treating the pores of mesoporous silica with tetrabutylammonium hydroxide. ing.

“A PPV / MCM-41 Composite Material”, Chem. Mater. 2004, Vol. 16, p. 2180-2186

  In order to put the π-conjugated polymer into practical use as a light-emitting material, further improvement in the quantum efficiency of light emission is required. In addition, colloidal crystals formed by particles carrying π-conjugated polymers are thought to be useful for applications as light-emitting materials. Conventionally, colloidal crystals with high regularity have been produced by particles carrying π-conjugated polymers. It was difficult to form.

  Thus, the main object of the present invention is to further increase the quantum efficiency of light emission by the π-conjugated polymer, and to easily form a highly ordered colloidal crystal of particles carrying the π-conjugated polymer. It is in.

  In one aspect, the present invention relates to a composite particle carrying a π-conjugated polymer and a method for producing the same. The production method according to the present invention includes a step of generating precursor particles containing a hydrolyzed polycondensate of alkoxysilane and a surfactant in a reaction solution containing alkoxysilane, a surfactant, water and an alcohol, and a precursor. A step of substituting at least a part of the surfactant in the particles with an ionic monomer, and generating a π-conjugated polymer from the ionic monomer to form a porous body of a hydrolyzed polycondensate and pores of the porous body And a step of obtaining composite particles containing a π-conjugated polymer supported therein.

  According to the method of the present invention, the quantum efficiency of light emission by the π-conjugated polymer can be further increased. The reason why such an effect is exhibited is not necessarily clear, but by utilizing an exchange reaction with a surfactant, a π-conjugated polymer can be reliably introduced into the pores, and mesoporous silica particles as in the conventional method Is not required to be treated with an alkali component, so that the high regularity of the pores is maintained, and further, the PPV tends to be more isolated due to the action of the surfactant remaining in the pores. Conceivable.

  In another aspect, the present invention relates to a method for producing a colloidal crystal. The production method according to the present invention includes a step of generating precursor particles containing a hydrolyzed polycondensate of alkoxysilane and a surfactant in a reaction solution containing alkoxysilane, a surfactant, water and an alcohol, and a precursor. A step of substituting at least a part of the surfactant in the particles with an ionic monomer, and generating a π-conjugated polymer from the ionic monomer to form a porous body of a hydrolyzed polycondensate and pores of the porous body A step of obtaining composite particles containing a π-conjugated polymer supported therein, and a step of forming colloidal crystals from a dispersion containing the composite particles.

  According to the method of the present invention, it is possible to easily form colloidal crystals with high regularity of particles carrying a π-conjugated polymer. Conventional particles carrying a π-conjugated polymer often have a π-conjugated polymer film covering the surface. For this reason, it has been difficult to stably obtain a dispersion of particles used for colloidal crystal production. On the other hand, the π-conjugated polymer is supported substantially only in the pores by supporting the π-conjugated polymer on the silica-based porous material using the exchange reaction with the surfactant as in the present invention. In addition, composite particles having a smooth surface can be obtained. Therefore, the dispersibility of the composite particles in a dispersion medium such as water has been greatly improved, and colloidal crystals using the dispersion can be easily formed.

  According to the present invention, it is possible to further increase the quantum efficiency of light emission by a π-conjugated polymer, and to easily form colloidal crystals with high regularity of particles carrying the π-conjugated polymer. .

It is a SEM photograph of precursor particles. 4 is a SEM photograph of composite particles of Comparative Example 1. 2 is a SEM photograph of composite particles of Example 1. It is a schematic diagram which shows the preparation methods of a colloidal crystal. 2 is a SEM photograph of colloidal crystals obtained from the composite particles of Example 1. 2 is an emission spectrum of a colloidal crystal obtained from the composite particles of Example 1. 2 is a transmission spectrum of a colloidal crystal obtained from the composite particles of Example 1. It is a SEM photograph of precursor particles. 4 is a SEM photograph of composite particles of Example 2. 4 is a SEM photograph of colloidal crystals obtained from the composite particles of Example 2. 4 is a SEM photograph of colloidal crystals obtained from the composite particles of Example 2. 2 is an emission spectrum of a colloidal crystal obtained from the composite particles of Example 2. 2 is a transmission spectrum of a colloidal crystal obtained from the composite particles of Example 2. 3 is an emission spectrum of a colloidal crystal obtained from the composite particles of Example 3. 4 is a transmission spectrum of a colloidal crystal obtained from the composite particles of Example 3. 4 is an emission spectrum of composite particles of Example 4. 7 is an emission spectrum of the composite particles of Example 5.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  The method for producing composite particles according to the present embodiment includes hydrolyzing polycondensation of alkoxysilane in a reaction solution containing alkoxysilane, surfactant, water and alcohol, and hydrolyzing polycondensate of alkoxysilane and surfactant. A step of generating precursor particles containing, a step of substituting at least a part of the surfactant in the precursor particles with an ionic monomer, and generating a π-conjugated polymer from the ionic monomer for hydrolysis. And a step of including a composite particle having a porous body of polycondensate and a π-conjugated polymer supported in pores of the porous body.

  When alkoxysilane and surfactant are mixed in a mixed solvent containing water and alcohol, the surfactant functions as a template for the porous body, and the hydrolytic polycondensation of alkoxysilane while incorporating the surfactant into the pores. A spherical porous body is formed. The hydrolysis polycondensate of alkoxysilane contains silicon oxide as a main component. That is, spherical precursor particles composed of a porous body of alkoxysilane hydrolyzed polycondensate (silicon oxide) and a surfactant supported in the pores of the porous body are formed.

  The alkoxysilane includes at least one of a tetraalkoxysilane having four alkoxy groups bonded to silicon atoms and a trialkoxysilane having three alkoxy groups bonded to silicon atoms. The types of these alkoxy groups are not particularly limited, but those having a relatively small number of carbon atoms in the alkoxy group (such as those having about 1 to 4 carbon atoms) such as methoxy group, ethoxy group, propoxy group and butoxy group are reacted. It is advantageous in terms of sex. The alkoxy group may be substituted with a hydroxy group (—OH). An organic group, a hydroxyl group or the like may be bonded to the silicon atom in the trialkoxysilane, and the organic group may be substituted with a substituent such as an amino group or a mercapto group.

  Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, and dimethoxydiethoxysilane. Examples of the trialkoxysilane include methoxysilanol, triethoxysilanol, trimethoxymethylsilane, trimethoxyvinylsilane, triethoxyvinylsilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyl. Trimethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ- (methacryloxypropyl) trimethoxysilane and β- (3,4-epoxycyclohexyl) ethyl There is trimethoxysilane. Examples of the hydroxyalkoxysilane include tetrakis (2-hydroxyethoxy) silane, tetrakis (3-hydroxypropoxy) silane, tetrakis (2-hydroxypropoxy) silane, and tetrakis (2,3-dihydroxypropoxy) silane. These alkoxysilanes are used alone or in combination of two or more.

  As the surfactant, a cationic surfactant is preferable, and an alkylammonium halide is particularly preferable. A preferred alkyl ammonium halide is at least one selected from the group consisting of tetradecyltrimethylammonium halide, hexadecyltrimethylammonium halide, and octadecyltrimethylammonium halide. The kind of halogen atom constituting the alkylammonium halide is not particularly limited, but a chlorine atom and a bromine atom are preferable from the viewpoint of availability. Surfactant is used 1 type or in combination of 2 or more types. However, since the type greatly affects the shape of the pores of the generated porous body, it is preferable to use only one type as the surfactant in order to obtain a spherical porous body that forms more uniform pores.

  The mixed solvent used for the production of the precursor particles includes water and alcohol. As the alcohol, for example, methanol, ethanol, isopropanol, n-propanol, ethylene glycol, glycerin or a mixture thereof is used.

  The amount of alcohol contained in the mixed solvent is preferably 20 to 55% by volume, more preferably 35 to 50% by volume. By using such a mixed solvent, substantially monodispersed spherical precursor particles can be produced particularly easily.

  The concentration of the surfactant contained in the mixed solvent is preferably 0.003 to 0.03 mol / L, more preferably 0.01 based on the total volume of the alkoxysilane, the surfactant and the reaction solution containing the mixed solvent. -0.02 mol / L. The concentration of alkoxylane is preferably 0.005 to 0.03 mol / L, more preferably 0.007 to 0.012 mol / L, based on the total volume of the reaction solution. By setting these concentration ranges, spherical precursor particles with higher uniformity can be obtained.

  The reaction liquid containing alkoxysilane, surfactant and mixed solvent is preferably basic. For this reason, the reaction solution preferably further contains a basic substance such as sodium hydroxide.

  At least a part of the surfactant in the generated precursor particles is replaced with an ionic monomer by a template ion exchange reaction. For example, the template ion exchange reaction can be advanced by a method in which precursor particles are brought into contact with a solution of an ionic monomer as necessary. Usually, there is a high possibility that the surfactant remains in the precursor particles after the template ion exchange reaction.

As the ionic monomer, an ionic compound that forms a π-conjugated polymer by a reaction including polymerization is used. For example, xylene bis (tetrahydrothiophenium chloride) and its derivatives represented by the following chemical formula (1) are suitable. In the following formulae, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group or an alkoxy group. In the formula (1), for example, R ¹ and R ² may be a hydrogen atom, R ¹ may be a methoxy group, and R ² may be a dodecyloxy group.

  Poly (1,4-phenylene vinylene) (PPV) represented by the following chemical formula (2) can be generated from the ionic monomer of the formula (1).

  After the template ion exchange reaction, by generating a π-conjugated polymer from the ionic monomer introduced into the pores, the silica-based porous body and the π-conjugated system supported in the pores of the silica-based porous body Composite particles having a polymer are formed. Depending on the conditions such as the heating temperature, the template exchange reaction may proceed, and at the same time, the reaction for producing a π-conjugated polymer from the introduced ionic monomer may proceed. The composite particles often further contain a surfactant. Xylene bis (tetrahydrothiophenium chloride) produces PPV through polymerization in the pores and subsequent elimination reaction. Xylene bis (tetrahydrothiophenium chloride) can generate PPV by heating at 200 to 225 ° C. in a reduced pressure atmosphere, for example.

  By increasing the heating time for producing a π-conjugated polymer such as PPV from an ionic monomer, composite particles having more excellent light emission characteristics can be obtained. Specifically, the heating time is preferably 0.5 hours or more, more preferably 2 hours or more. The upper limit of the heating time is not particularly limited, but usually about 50 hours or less is sufficient.

  From the composite particles obtained by the above method, colloidal crystals having high crystallinity can be easily formed by an ordinary method. Specifically, for example, a method in which a dispersion liquid in which composite particles are dispersed in a dispersion medium such as water or alcohol is filled in a film-like space and the dispersion medium is removed from the filled dispersion liquid, or heat convection is performed. Colloidal crystals can be formed by the vertical deposition method utilized. In the vertical deposition method, the composite particles in the dispersion are moved to the dispersion interface by thermal convection to form colloidal crystals at the dispersion interface. In any method, it is preferable that the composite particles have high dispersibility in the dispersion medium.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Synthesis of precursor particles 1
To a mixed solvent of 3326 g of water and 4610 g of methanol, 38.3 g of octadecyltrimethylammonium chloride (surfactant) and 34.2 g of 1N sodium hydroxide were added and stirred at room temperature. A mixed solution of tetramethoxysilane and methanol (26.4 g / 30.0 g) was added thereto, and stirring was continued. Tetramethoxysilane was completely dissolved and a white powder was precipitated. The reaction was stirred at room temperature for a further 8 hours and left overnight. Thereafter, the powder taken out by filtration was washed with deionized water three times and dried to obtain 19.22 g of precursor particles. The obtained precursor particles were confirmed by SEM observation to be monodispersed spherical particles having an average particle diameter of 850 nm (FIG. 1).

Comparative Example 1
The precursor particles were fired at 540 ° C. for 6 hours to remove the surfactant and obtain silica-based porous (mesoporous silica) particles. The silica-based porous particles were dried at 100 ° C. under vacuum, and further treated with a 1M tetrabutylammonium solution under a nitrogen atmosphere. Thereafter, the powder was immersed in a dehydrated ethanol solution (10 to 20% w / w) of xylene bis (tetrahydrothiophenium chloride) for 24 hours. After immersion, the powder was washed with ethanol and water to remove excess monomer and alkali components. The washed powder was vacuum-dried at room temperature and further heat-treated at 200 ° C. for 6 hours in an atmosphere of 10 ⁻² Torr to obtain composite particles carrying PPV in the pores. FIG. 2 is an SEM photograph of the obtained composite particles. It was confirmed that the particle surface was covered with a thin PPV film.

Comparative Example 2
The precursor particles were calcined at 550 ° C. for 6 hours, and the surfactant was removed to obtain silica-based porous (mesoporous silica) particles. The silica-based porous particle powder was dispersed in a dehydrated ethanol solution (10 to 20% w / w) of xylene bis (tetrahydrothiophenium chloride). Ethanol was distilled off from the obtained dispersion using an evaporator to obtain a white powder. This white powder was heated at 200 ° C. for 6 hours in an atmosphere of 10 ⁻² Torr. After heating, the powder remained white and did not emit light at all even when irradiated with light. That is, by bringing the guest molecule solution into contact with the mesoporous silica particles and then distilling off the solvent, composite particles in which the polymer is incorporated into the target pores cannot be obtained.

Example 1
The precursor particles after drying are put into a methanol solution (10 to 20% w / w) of xylene bis (tetrahydrothiophenium chloride) and heated in an oil bath at 60 ° C. for 4 hours. A template exchange reaction for exchanging the surfactant and the PPV monomer in the mesopores of the silica-based porous material was performed. Excess monomer was removed from the powder after the reaction by washing with methanol. The washed powder was vacuum-dried at room temperature and further heat-treated at 200 to 225 ° C. for 6 hours in an atmosphere of 10 ⁻² Torr to obtain spherical composite particles carrying PPV in the pores. The obtained composite particles were yellow. FIG. 3 is an SEM photograph of the obtained composite particles. Unlike Comparative Example 1 (FIG. 2), the particle surface was confirmed to be very smooth without being covered by the PPV film.

Quantum yield of light emission Using a dispersion obtained by dispersing the composite particles obtained in Comparative Example 1 and Example 1 in ethanol, the quantum yield of light emission by these particles was measured. Example 1 was 0.98. These quantum yields are the conversion efficiencies from excitation light to fluorescence. The larger this value, the higher the conversion efficiency and the less waste of energy. The light emission quantum yield of PPV not supported on the porous body is usually about 0.15 to 0.25, and PPV is supported in the pores of the silica-based porous particles by the method of Comparative Example 1. The quantum yield was improved. This is presumably because the presence of PPV chains in the pores inhibits energy transfer and decomposition of the PPV chains by oxygen. In Example 1, the quantum yield was further improved and reached an extremely high value.

Production and Characterization of Colloidal Crystal FIG. 4 is a schematic diagram showing a method for producing a colloidal crystal. A glass cell 10 was prepared by bonding two glass plates 11 cleaned by sulfuric acid treatment with two spacers 15 having a thickness of 10 μm interposed therebetween, and a capillary 21 (φ4 mm) as a dispersion introducing tube was attached thereto. . A 1% by mass aqueous dispersion 20 of the composite particles obtained in Example 1 was prepared in a glass sample bottle 22, and the dispersion was subjected to ultrasonic treatment. Thereafter, the dispersion 20 was introduced into the glass cell 10 while stirring the dispersion 20 with a magnetic stirrer 25. The composite particle dispersion of Example 1 had high stability, and the dispersion could be continuously introduced into the glass cell 10 through the capillary 21. After introduction, colloidal crystals were formed by evaporating water from the spacer portion. The obtained colloidal crystal had a pale yellow color derived from PPV, and a structural color serving as an index of crystal regularity was also observed. FIG. 5 is an SEM photograph of the obtained colloidal crystal. From the SEM photograph, it was confirmed that the colloidal crystal has a highly regular and closely packed structure.

  On the other hand, when an attempt was made to produce a colloidal crystal by the same method using the composite particles of Comparative Example 1, a stable dispersion could not be obtained even after long-time ultrasonic treatment, and the composite was stopped when stirring was stopped. The particles seemed to settle immediately. Even under stirring, the composite particles could not be introduced into the glass cell because the composite particles separated from the water in the capillary.

  6 and 7 are the emission spectrum and transmission spectrum of the colloidal crystal obtained from the composite particles of Example 1, respectively. As shown in the emission spectrum of FIG. 6, the colloidal crystal showed strong emission derived from PPV centered at 500 nm. In FIG. 6, the peak at 440 nm is due to excitation light. As shown in the transmission spectrum of FIG. 7, a very sharp dip was observed around 1700 nm. The position of the dip coincides with the wavelength due to Bragg reflection of the colloidal crystal, which is expected from the particle diameter of the composite particle. From this, it was suggested that the regularity of the colloidal crystal is high.

Synthesis of precursor particles 2
To a mixed solvent of 4126 g of water and 3810 g of methanol, 38.2 g of hexadecyltrimethylammonium chloride (surfactant) and 34.2 g of 1N sodium hydroxide were added and stirred at room temperature. A mixed solution of tetramethoxysilane and methanol (26.4 g / 30.0 g) was added thereto, and stirring was continued. Tetramethoxysilane was completely dissolved and a white powder was precipitated. The reaction was stirred at room temperature for a further 8 hours and left overnight. Thereafter, the powder taken out by filtration was washed three times with deionized water and dried to obtain 18.29 g of precursor particles. The obtained precursor particles were confirmed by SEM observation to be monodispersed spherical particles having an average particle diameter of 480 nm (FIG. 8).

Example 2
Using the precursor particles after drying, spherical composite particles carrying PPV in the pores were obtained in the same procedure as in Example 1. FIG. 9 is an SEM photograph of the obtained composite particles. As in Example 1, no PPV film covering the particle surface was observed, and a very smooth surface was confirmed.

Quantum yield of light emission The quantum yield of light emission by the composite particles obtained in Example 2 was 0.92 when measured using an ethanol dispersion of the composite particles, which was very high as in Example 1. there were.

Production and Characterization of Colloidal Crystal By the method using the glass cell of FIG. 4, a colloidal crystal exhibiting a structural color could be obtained using the composite particles of Example 2 (FIG. 10). Furthermore, colloidal crystals could be formed by the following vertical deposition method using the thermal convection phenomenon using the composite particles of Example 2 (FIG. 11). In the case of the composite particles of Example 1, although the dispersibility of the particles themselves was excellent, precipitation was likely to occur due to the large particle size, and it was difficult to produce colloidal crystals by the vertical deposition method performed without stirring.
(1) Disperse particles in ethanol at a concentration of 1% by mass to prepare an ethanol dispersion, which is subjected to ultrasonic treatment.
(2) A glass plate hydrophilized with sulfuric acid is immersed in an ethanol dispersion and kept at 50 ° C. without stirring.
(3) The particles are moved to the dispersion liquid interface (glass plate surface) by thermal convection to form colloidal crystals on the glass plate surface.

  Observation of the colloidal crystal by SEM and measurement of emission spectrum and transmission spectrum were performed. 12 and 13 are an emission spectrum and a transmission spectrum of a colloidal crystal obtained by the glass cell method, respectively. As shown in the emission spectrum of FIG. 12, the colloidal crystal showed strong emission derived from PPV centered at 500 nm. In FIG. 12, the peak at 440 nm is due to excitation light. As shown in the transmission spectrum of FIG. 13, a very sharp dip was observed near 960 nm. The position of the dip coincides with the wavelength due to Bragg reflection of the colloidal crystal, which is expected from the particle diameter of the composite particle. From this, it was suggested that the regularity of the colloidal crystal is high.

Synthesis of precursor particles 3
To a mixed solvent of 873.2 g of water, 624 g of methanol and 96 g of ethanol, 7.04 g of hexadecyltrimethylammonium chloride (surfactant) and 6.84 g of 1N sodium hydroxide were added and stirred at room temperature. Then, a mixed solution of tetramethoxysilane and 3-aminopropyltrimethoxysilane (5.02 g / 0.31 g) was added as a silica source, and the stirring was further continued. As a result, the silica source was completely dissolved and a white powder was obtained. Precipitated. The reaction was stirred at room temperature for a further 8 hours and left overnight. Thereafter, the powder taken out by filtration was washed with deionized water three times and dried to obtain 3.11 g of precursor particles. The obtained precursor particles were confirmed by SEM observation to be monodispersed spherical particles having an average particle diameter of 330 nm (FIG. 8).

Example 3
Using the precursor particles after drying, spherical composite particles carrying PPV in the pores were obtained in the same procedure as in Example 1.

Quantum yield of light emission The quantum yield of light emission by the composite particles obtained in Example 2 was 0.90 when measured using an ethanol dispersion of the composite particles, which was a very high value as in Example 1. there were.

Production and Characterization of Colloidal Crystal Using the composite particles of Example 3, a colloidal crystal having a very regular structure could be obtained by the vertical deposition method similar to that of Example 2. 14 and 15 are the emission spectrum and transmission spectrum of the obtained colloidal crystal, respectively. As shown in the emission spectrum of FIG. 14, the colloidal crystal showed strong emission derived from PPV centered at 500 nm. In FIG. 14, the peak at 400 nm is due to excitation light. As shown in the transmission spectrum of FIG. 15, a very sharp dip was observed around 610 nm. The position of the dip coincides with the wavelength due to Bragg reflection of the colloidal crystal, which is expected from the particle diameter of the composite particle. From this, it was suggested that the regularity of the colloidal crystal is high.

Example 4
Precursor particles synthesized in “Precursor Particle Synthesis 1” are put into xylene bis (tetrahydrothiophenium chloride) ethanol solution (10-20% w / w) and heated in an oil bath at 80 ° C. for 6 hours. did. The template exchange reaction for exchanging the surfactant and the PPV monomer in the mesopores of the silica-based porous material constituting the precursor particles by heating proceeds, and at the same time, the polymerization of the PPV monomer proceeds to form a spherical yellow color Of composite particles were obtained. Excess monomer was removed by washing to obtain spherical composite particles carrying PPV in the pores. FIG. 16 is an emission spectrum of the obtained composite particles.

Example 5
Precursor particles synthesized in “Precursor Particle Synthesis 2” are put into an ethylene glycol solution (10-20% w / w) of xylene bis (tetrahydrothiophenium chloride) for 6 hours in an oil bath at 100 ° C. Heated. The template exchange reaction for exchanging the surfactant and the PPV monomer in the mesopores of the silica-based porous material constituting the precursor particles by heating proceeds, and at the same time, the polymerization of the PPV monomer proceeds to form a spherical yellow color Of composite particles were obtained. Excess monomer was removed by washing to obtain spherical composite particles carrying PPV in the pores. FIG. 17 is an emission spectrum of the obtained composite particles.

  DESCRIPTION OF SYMBOLS 10 ... Glass cell, 11 ... Glass plate, 15 ... Spacer, 20 ... Dispersion liquid, 21 ... Capillary, 22 ... Sample bottle, 25 ... Stirrer.

Claims (4)

Producing a precursor particle containing the hydrolyzed polycondensate of alkoxysilane and the surfactant in a reaction solution containing alkoxysilane, a surfactant, water and alcohol;
Replacing at least a portion of the surfactant in the precursor particles with an ionic monomer;
Producing a π-conjugated polymer from the ionic monomer to obtain a composite particle containing the hydrolyzed polycondensate porous body and the π-conjugated polymer supported in the pores of the porous body; ,
A method for producing composite particles.   Composite particles obtainable by the production method according to claim 1. Producing a precursor particle containing the hydrolyzed polycondensate of alkoxysilane and the surfactant in a reaction solution containing alkoxysilane, a surfactant, water and alcohol;
Replacing at least a portion of the surfactant in the precursor particles with an ionic monomer;
Producing a π-conjugated polymer from the ionic monomer to obtain a composite particle containing the hydrolyzed polycondensate porous body and the π-conjugated polymer supported in the pores of the porous body; ,
Forming a colloidal crystal of the composite particles from a dispersion containing the composite particles;
A method for producing a colloidal crystal.   A colloidal crystal obtainable by the production method according to claim 3.