JP5326086B2 - Solar energy utilization apparatus and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar energy utilization device which has improved durability such as wear resistance and weather resistance, etc., water droplet taking-off property (also called droplet slidable), and antifouling property, and to provide a method for manufacturing the device. <P>SOLUTION: In the solar energy utilizing device 10, a light-incident-side transparent base material 21 is coated with a coat film 23 made of a first film compound having a first functional group, and at least a part of surfaces of water-shedding transparent particles 12 are coated with coat film 34 made of a second film compound having a second functional group, and the transparent particles 12 are fixed to the surface of the light-incident-side transparent base material 21 via bonding formed by coupling reaction of the first and second functional groups with coupling reaction groups contained in a coupling agent, to constitute a water repellent transparent member 24. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to a solar energy utilization apparatus having a durable, high-performance water separation property (also referred to as water slidability) and a water-repellent coating film having a surface reflection reduction effect on incident light formed thereon, and its manufacture. It is about the method.

In general, it is already well known that a solution composed of a fluorocarbon group-containing chlorosilane-based adsorbent and a non-aqueous organic solvent can be used for chemical adsorption in the liquid phase to form a water- and oil-repellent antifouling monolayer. (For example, refer to Patent Document 1).

The manufacturing principle of such a monomolecular film in a solution is to form a monomolecular film by using a dehydrochlorination reaction between active hydrogen such as hydroxyl group on the substrate surface and chlorosilyl group of chlorosilane-based adsorbent. is there.

JP-A-4-132737

For example, the conventional monomolecular film obtained by the above method uses a covalent bond (siloxane bond) between the adsorbent and the substrate surface, and thus has a certain degree of wear resistance and water / oil / oil repellent / antifouling function. However, there is a problem that the wear resistance and water repellency are insufficient.

The present invention relates to a solar energy utilization device such as a solar cell or a solar water heater that is required to have water / oil / oil repellent antifouling performance, durability such as wear resistance and weather resistance, water droplet separation (sliding), and water resistance. An object of the present invention is to provide a solar energy utilization device with improved soiling and a method for producing the same.

The solar energy utilization apparatus according to the first invention that meets the above-described object is a light incident side transparent base material that is coated with a film formed by a first film compound having a first functional group that is an epoxy group or an amino group . When the first functional group is an epoxy group, the water-repellent transparent fine particles whose surface is coated with at least a part of the surface with a film formed by the first film compound are each one or more amino groups and When the imino group and the first functional group are amino groups, a coupling agent having two or more coupling groups which are two or more epoxy groups or isocyanate groups, and the coupling of the first functional group It is fixed through an N—CH ₂ CH (OH) bond or NH—CONH bond formed by the reaction.

In the solar energy utilization apparatus according to the first invention, the first film compound is covalently bonded to the light incident side surface of the light incident side transparent substrate and the surface of the transparent fine particles, respectively, via Si. Preferably it is.
Surface groups such as hydroxyl groups present on the light incident side surface of the light incident side transparent substrate and the surface of the transparent fine particles react with Si of the first film compound to form a stable covalent bond such as a siloxane bond. Form. Therefore, the peel resistance of the coating formed by the first film compound that covers the surfaces of the light incident side transparent substrate and the transparent fine particles is improved, and the falling off of the water-repellent transparent fine particles due to the peeling of these coatings is suppressed. Therefore, the weather resistance of the solar energy utilization apparatus obtained is improved.

In the solar energy utilization apparatus according to the first invention, it is preferable that either one or both of the films formed by the first film compound are monomolecular films.

In the solar energy utilization apparatus according to the first invention, the surface of the water-repellent transparent fine particles exposed to the atmosphere is further covered with a water-repellent coating formed by the third film compound having a water-repellent functional group. It may be.

In the solar energy utilization apparatus according to the first aspect of the present invention, it is preferable that the water repellent functional group includes a —CF ₃ group.

In the solar energy utilization apparatus according to the first invention, the water repellent film formed by the third film compound is preferably a monomolecular film.

In the solar energy utilization apparatus according to the first invention, the transparent fine particles may be selected from the group consisting of translucent silica, alumina, and zirconia.

In the solar energy utilization apparatus according to the first invention, it is preferable that the transparent fine particles have an average particle size of 10 nm to 300 nm.
“The average particle diameter is 10 nm or more” means that the primary average particle diameter of the transparent fine particles is 10 nm or more and the ratio of the number of fine particles having a particle diameter of less than 10 nm to the whole fine particles is 5% or less. Say. Similarly, “the average particle diameter is 300 nm or less” means that the primary average particle diameter of the transparent fine particles is 300 nm or less and the ratio of the number of fine particles having a particle diameter exceeding 300 nm to the total fine particles is 5% or less. Say.
Furthermore, if these fine particles are hollow fine particles, the effect of improving the light transmittance is high.

In the solar energy utilization apparatus according to the first invention, the bond formed by the coupling reaction is an N—CH ₂ CH (OH) bond formed by a reaction between an amino group or an imino group and an epoxy group. Also good.

In the solar energy utilization apparatus according to the first invention, the bond formed by the coupling reaction may be an NH—CONH bond formed by a reaction between an amino group or an imino group and an isocyanate group.

In the solar energy utilization apparatus according to the first aspect of the invention, the contact angle with respect to water is preferably 150 degrees or more and 180 degrees or less.

The manufacturing method of the solar energy utilization apparatus which concerns on 2nd invention contains the 1st film compound which has the 1st functional group which is an epoxy group or an amino group, and a 1st coupling group at the both ends of a molecule | numerator, respectively. The solution is brought into contact with the light incident side surface of the light incident side transparent base material to form a bond between the first binding group and the surface of the light incident side transparent base material. A step A of preparing a coated light incident side transparent base material having a film to be formed on the light incident side surface, a second solution containing the first film compound is brought into contact with the surface of the transparent fine particles, and the first Forming a bond between a bonding group and the surface of the transparent fine particle, and preparing coated transparent fine particles in which at least a part of the surface of the transparent fine particle is coated with a film formed by the first film compound; , respectively when the first functional group is an epoxy group 1 Amino group and imino group of the above, wherein, when the first functional group is an amino group, a coupling agent having two or more coupling groups of 2 or more epoxy groups or isocyanate groups, the coating light entrance side A surface of the transparent substrate on the light incident side and the surface of the coated transparent fine particle are brought into contact with each other, and an N—CH ₂ CH (OH) bond or NH is formed by a coupling reaction between the first functional group and the coupling reactive group. And a step C of forming a -CONH bond and bonding and fixing the coated transparent fine particles to the light incident side surface of the coated light incident side transparent substrate.

In the method for manufacturing a solar energy utilization device according to the second invention, it is preferable to wash away unreacted substances after one or both of the steps A and B.
The “unreacted material” means an unreacted first film compound in the step A, and an unreacted second film compound in the step B.

In the method for manufacturing a solar energy utilization device according to the second invention, the bond formed by the coupling reaction is an N—CH ₂ CH (OH) bond formed by a reaction between an amino group or an imino group and an epoxy group. It may be.

In the method for manufacturing a solar energy utilization device according to the second invention, the bond formed by the coupling reaction may be an NH-CONH bond formed by a reaction between an amino group or an imino group and an isocyanate group. .

In the method for manufacturing a solar energy utilization device according to the second invention, one or both of the first film compounds contained in the first solution may be an alkoxysilane compound.
The “alkoxysilane compound” refers to a film compound in which the first bonding group is an alkoxysilyl group represented by the general formula —Si (OR) ₃ (R represents an arbitrary alkyl group).

In the method for manufacturing a solar energy utilization device according to the second invention, one or both of the first and second film compounds respectively contained in the first solution may be a halosilane compound.
Note that "halosilane compound", a first coupling group has the general formula -SiX 3 _(X is chlorine, bromine, and one or represents iodine) refers to a film compound is a halosilyl group represented by.

In the method for manufacturing a solar energy utilization device according to the second invention, the first and second solutions containing the alkoxysilane compound further include a carboxylic acid metal salt, a carboxylic acid ester metal salt, and a carboxylic acid metal. It is preferable to include one or more compounds selected from the group consisting of a salt polymer, a carboxylic acid metal salt chelate, a titanate ester, and a titanate ester chelate.

In the method for manufacturing a solar energy utilization device according to the second invention, the first and second solutions containing the alkoxysilane compound further include a ketimine compound, an organic acid, an aldimine compound, an enamine compound, and an oxazolidine compound. And one or more compounds selected from the group consisting of aminoalkylalkoxysilane compounds.

In the method for manufacturing a solar energy utilization device according to the second invention, after the step C, the surface of the coated transparent fine particles exposed to the atmosphere, the water repellent functional groups at both ends of the molecule, and the first functional Contacting a third solution comprising a second membrane compound each having a second linking group that reacts with a group to form a bond between the second linking group and the first functional group; The method may further include a step D of forming a water repellent film formed by the second film compound on the surface exposed to the atmosphere.
In this case, it is preferable to wash away the unreacted second film compound after the step D.

In the method for manufacturing a solar energy utilization device according to the second invention, the third film compound contained in the third solution may be an alkoxysilane compound containing a fluorocarbon group.
The “alkoxysilane compound” refers to a film compound in which the third bonding group is an alkoxysilyl group represented by the general formula —Si (OR) ₃ (R represents an arbitrary alkyl group).

In the method for manufacturing a solar energy utilization device according to the second invention, the third film compound contained in the third solution may be a halosilane compound containing a fluorocarbon group.
The “halosilane compound” refers to a film compound in which the third bonding group is a halosilyl group represented by the general formula —SiX ₃ (X represents any one of chlorine, bromine, and iodine).

In the method for manufacturing a solar energy utilization device according to the second invention, the third solution further includes a carboxylic acid metal salt, a carboxylic acid ester metal salt, a carboxylic acid metal salt polymer, a carboxylic acid metal salt chelate, and a titanic acid ester. And one or more compounds selected from the group consisting of titanate chelates.

In the method for manufacturing a solar energy utilization device according to the second invention, the third solution is further selected from the group consisting of a ketimine compound, an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound. It is preferable to include 1 or 2 or more compounds.

In the solar energy utilization apparatus according to any one of claims 1 to 9 , and the solar energy utilization apparatus according to claims 10 to 21 , a water repellent / oil repellent / antifouling function is required, for example, a solar cell, a solar water heater, In a solar energy utilization device such as a greenhouse, a solar energy utilization device excellent in durability such as wear resistance and weather resistance, water droplet water separation property, and antifouling property can be provided.

Further, the surface of the light incident side transparent base material whose surface is coated with the coating film formed by the first film compound is water-repellent transparent whose at least part of the surface is coated with the coating film formed by the first film compound. The fine particles are fixed through a bond formed by a coupling reaction between the first functional group and the coupling reactive group , and the solar energy utilization device exhibits a complicated surface shape having irregularities. Therefore, it has high water and oil repellency due to the so-called “lotus leaf effect”. Furthermore, since the transparent fine particles fixed on the surface of the light incident side transparent base material whose surface is coated with the film formed by the first film compound has an action of gently changing the refractive index, it has an antireflection effect. Have.

In the solar energy utilization apparatus according to claim 2, the first and second film compounds are covalently bonded to the light incident side surface of the light incident side transparent base and the surface of the surface of the transparent fine particles through Si, respectively. Therefore, the weather resistance can be improved.

In the solar energy utilization apparatus according to claim 3, since one or both of the films formed by the first film compound and the second film compound are monomolecular films, reflection and scattering of light by these films Can be suppressed to a minimum, and has high light transmittance.

In the solar energy utilization device according to claim 4, since the surface of the exposed portion of the transparent fine particles is covered with the water repellent coating formed by the third film compound having a water repellent functional group, for example, it is inexpensive. Water-repellent transparent fine particles can be produced inexpensively and easily using raw materials such as silica, alumina and zirconia which are excellent in wear resistance and the like but are hydrophilic.

In the solar energy utilization system according to claim 5, since the water-repellent functional group contains a group -CF _3, it is possible to improve the water repellency can be imparted also to oil repellency and antifouling property.
In the solar energy utilization apparatus according to claim 6, since the water-repellent coating formed by the third film compound is a monomolecular film, the influence of light reflection and scattering by the water-repellent coating can be suppressed to a minimum, and high It has optical transparency.

In the solar energy utilization apparatus according to claim 7, since the transparent fine particles are selected from the group consisting of silica, alumina, and zirconia, which are inexpensive and excellent in water resistance and wear resistance, the weather resistance and Abrasion resistance can be improved.

In the solar energy utilization apparatus according to claim 8, since the average particle diameter of the transparent fine particles is 10 nm or more and 300 nm or less, scattering of incident light can be suppressed, and utilization efficiency of light energy can be improved.

In the solar energy utilization apparatus according to the ninth aspect , since the contact angle with respect to water is not less than 150 degrees and not more than 180 degrees, the falling angle of the water droplet becomes small and the water droplet does not substantially adhere.

In the method for manufacturing a solar energy utilization device according to claim 11 , since the unreacted material is washed and removed after one or both of steps A and B, the washed coating is a monomolecular film. Therefore, the influence of light reflection and scattering by these films in the solar energy utilization device can be suppressed to the minimum, and a solar energy utilization device having high light transmittance can be obtained.

13. The method for manufacturing a solar energy utilization device according to claim 12 , wherein one or both of the first and second film compounds respectively contained in the first and second solutions react with an active hydrogen group. Since it is an alkoxysilane compound that does not generate harmful hydrogen chloride, the solar energy utilization device can be manufactured more safely, and corrosion of the manufacturing equipment and generation of acidic waste liquid can be suppressed.

In the manufacturing method of the solar energy utilization apparatus according to claim 13 , either one or both of the first and second film compounds contained in the first and second solutions are highly reactive with active hydrogen groups. Since it is a halosilane compound, the solar energy utilization device can be manufactured with higher efficiency, and the addition of a catalyst becomes unnecessary.

In the manufacturing method of the solar energy utilization apparatus of Claim 14, what contains an alkoxysilane compound among 1st and 2nd solutions is further used as a condensation catalyst as carboxylic acid metal salt, carboxylic acid ester metal salt, carboxylic acid Since one or more compounds selected from the group consisting of metal salt polymers, carboxylic acid metal salt chelates, titanate esters and titanate ester chelates are included, the reaction time between the alkoxysilane compound and the active hydrogen group is shortened, The solar energy utilization device can be manufactured with higher efficiency.

16. The method for manufacturing a solar energy utilization device according to claim 15 , wherein the first and second solutions containing an alkoxysilane compound include a ketimine compound, an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane. Since one or more compounds selected from the group consisting of compounds are further included, the reaction time between the alkoxysilane compound and the active hydrogen group can be shortened, and the solar energy utilization device can be manufactured more efficiently. . In particular, when both of these compounds and the above condensation catalyst are included, the reaction time can be further shortened.

In the method for manufacturing a solar energy utilization device according to claim 16, in step D, the exposed surface of the transparent fine particles is covered with a water repellent coating formed by the second film compound having a water repellent functional group. Therefore, for example, water-repellent transparent fine particles can be produced inexpensively and easily using raw materials such as silica, alumina and zirconia which are inexpensive and excellent in abrasion resistance but are hydrophilic.

In the method for manufacturing a solar energy utilization device according to claim 17, since the unreacted second film compound is washed and removed after step D, the water-repellent film formed by the second film compound is a monomolecular film. is there. Therefore, the influence of light reflection and scattering by the water repellent coating can be suppressed to a minimum, and a solar energy utilization device having high light transmittance can be obtained.

In the manufacturing method of the solar energy utilization apparatus according to claim 18, the second film compound contained in the third solution contains a fluorocarbon group, and harmful hydrogen chloride is reacted with the active hydrogen group. Since it is the alkoxysilane compound which does not generate | occur | produce, while being able to manufacture a solar energy utilization apparatus more safely, generation | occurrence | production of corrosion of a manufacturing facility and generation | occurrence | production of an acidic waste liquid can be suppressed.

In the method for manufacturing a solar energy utilization device according to claim 19, since the second film compound contained in the third solution is a halosilane compound containing a fluorocarbon group and highly reactive with an active hydrogen group, The solar energy utilization device can be manufactured with higher efficiency, and the addition of a catalyst becomes unnecessary.

The method for manufacturing a solar energy utilization device according to claim 20 , wherein the third solution further includes a carboxylic acid metal salt, a carboxylic acid ester metal salt, a carboxylic acid metal salt polymer, a carboxylic acid metal salt chelate, titanium as a condensation catalyst. Since one or two or more compounds selected from the group consisting of acid esters and titanate chelates are included, the reaction time between the alkoxysilane compound and the active hydrogen group is shortened, and the solar energy utilization device can be manufactured more efficiently. It can be carried out.

The method for producing a solar energy utilization device according to claim 21 , wherein the third solution is selected from the group consisting of a ketimine compound, an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound. Since two or more compounds are further included, the reaction time between the alkoxysilane compound and the active hydrogen group can be shortened, and the solar energy utilization device can be manufactured more efficiently. In particular, when both of these compounds and the above condensation catalyst are included, the reaction time can be further shortened.

Hereinafter, a solar energy utilization apparatus according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the solar energy utilization apparatus which concerns on one embodiment of this invention is the solar cell 10, Comprising: It has the water-repellent glass plate 24 (an example of a water-repellent translucent member).
The water-repellent glass plate 24 is a monomolecular film (an example of a film formed by the first film compound) 23 of a first film compound having an epoxy group (an example of a first functional group) and has a light incident side surface. the coated surface of the glass substrate 21 which is an example of a light incident side transparent substrate, the surface of the first monolayer film compound (an example of a film formed of the first film compound) 34 having an epoxy group The water-repellent alumina fine particles 12 as an example of the water-repellent transparent fine particles coated with at least a part of the nitrogen atom are the 1- and 3-position nitrogen atoms (coupling reaction) of 2-methylimidazole as an example of the coupling agent. An example of a group) and a structure fixed through a bond formed by a coupling reaction with an epoxy group.
The water-repellent alumina fine particles 12 are alumina fine particles 31 as an example of transparent fine particles whose surface is coated with a monomolecular film 34 of the first film compound (that is, epoxidized alumina fine particles 33 as an example of coated transparent fine particles). The surface of the portion exposed to the atmosphere side of the halosilane compound having a fluorocarbon group (an example of a water repellent functional group) containing a CF ₃ group (for example, a perfluorooctyl group (CF ₃ (CF ₂ ) ₇ —)) ( It is having further coated structure in one example) of the water-repellent film formed of water-repellent monomolecular film 13 (second film compound formed of one example) of a second film compound.

On the side opposite to the light incident side of the water repellent glass plate 24 (back side), a silver paste comb electrode 51 formed using a printing method, an n-type semiconductor layer 52 formed using a vapor deposition method, and a p-type. A solar cell layer 60 having a semiconductor layer 53 and an aluminum back electrode 54 (also serving as a reflective layer) is sequentially formed.
When the junction surface (pn junction) between the n-type semiconductor layer 52 and the p-type semiconductor layer 53 is irradiated with light having energy larger than the forbidden band width (band gap energy), a photovoltaic force is generated, and the silver paste comb An electromotive force is generated between the mold electrode 51 and the aluminum vapor deposition back electrode 54.

The solar cell 10 is manufactured by bringing a first solution containing an alkoxysilane compound having an epoxy group (an example of a first film compound) into contact with the light incident side surface of the glass substrate 21 to obtain an alkoxy of an alkoxysilane compound. Due to the reaction between the silyl group (an example of the first bonding group) and the hydroxyl group 22 on the surface of the glass substrate 21 schematically shown in FIG. a step a of the surface to produce a epoxy glass substrates coated (one example of a coated optical incident side transparent substrate) 11 (FIG. 2 (b)), a second solution containing an alkoxysilane compound having an epoxy group , and an alkoxysilyl group of the alkoxysilane compound, schematically brought into contact with the surface of the alumina particles 31 shown in FIG. 3 (a), by reaction with hydroxyl groups 32, a monomolecular film 34 of the first film compound Step B for producing the surface-coated epoxidized alumina fine particles 33 (FIG. 3 (b)), and 2-methylimidazole is brought into contact with the epoxidized glass substrate 11 in advance, and after the reaction, unreacted 2-methyl After the imidazole is removed and the monomolecular film 14 of 2-methylimidazole is formed on the surface, the epoxidized alumina fine particle 33 is brought into contact with the surface, and the fine particle fixed glass group in which the alumina fine particle is bonded to the surface through a coupling bond. Step C for producing the material 41 (FIG. 4) and a third solution containing a halosilane compound having a fluorocarbon group and a halosilyl group (an example of a second bonding group) at both ends of the molecule are treated with epoxidized alumina fine particles. 33 is brought into contact with the surface exposed to the atmosphere side to form a bond between the epoxy group and the halosilyl group. Surface water-repellent monomolecular film 13 that issued and a step D of further forming (see FIG. 1).
Hereinafter, the processes A to D will be described in more detail.

In step A, the epoxidized glass substrate 11 whose surface is covered with the monomolecular film 23 of the first film compound is manufactured.
There is no restriction | limiting in particular about the material of the glass base material 21 used for manufacture of the epoxidized glass base material 11, and a magnitude | size, The arbitrary glass base materials used in the solar cell 10 can be used. Further, if an active hydrogen group such as a hydroxyl group is present on the surface, a surface coating such as an antireflection film may be formed. In the present embodiment, the active hydrogen group is the hydroxyl group 22, but may be an amino group or an imino group containing active hydrogen.

The first solution used for producing the epoxidized glass substrate 11 is a condensation catalyst for accelerating the condensation reaction between the alkoxysilane compound having an epoxy group and the alkoxysilyl group and the hydroxyl group 22 on the surface of the glass substrate 21. And a non-aqueous organic solvent.

The alkoxysilane compound having an epoxy group has a functional group containing an epoxy group (oxirane ring) and an alkoxysilyl group at both ends of the linear alkylene group, and is represented by the following general formula (Formula 1). An alkoxysilane compound is preferable.

In the above formula, E represents a functional group having an epoxy group, m represents an integer of 3 to 20, and R represents an alkyl group having 1 to 4 carbon atoms.

As an example of the alkoxysilane compound which has an epoxy group which can be used in process A, the compound shown to following (1)-(12) is mentioned.

(1) (CH ₂ OCH) CH ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) _{3
(2) (CH 2 OCH)} CH 2 O (CH 2) 7 Si (OCH 3) 3
_{(3) (CH 2 OCH)} CH 2 O (CH 2) 11 Si (OCH 3) 3
_{(4) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 2 Si (OCH 3) 3
_{(5) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 4 Si (OCH 3) 3
_{(6) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 6 Si (OCH 3) 3
_{(7) (CH 2 OCH)} CH 2 O (CH 2) 3 Si (OC 2 H 5) 3
_{(8) (CH 2 OCH)} CH 2 O (CH 2) 7 Si (OC 2 H 5) 3
(9) (CH ₂ OCH) CH ₂ O (CH ₂ ) ₁₁ Si (OC ₂ H ₅ ) _{3
(10) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 2 Si (OC 2 H 5) 3
_{(11) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 4 Si (OC 2 H 5) 3
_{(12) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 6 Si (OC 2 H 5) 3

Here, the (CH ₂ OCH) CH ₂ O— group represents a functional group (glycidyloxy group) represented by Chemical Formula ₂ , and the (CH ₂ CHOCH (CH ₂ ) ₂ ) CH— group is represented by Chemical Formula 3. Represents a functional group (3,4-epoxycyclohexyl group).

As the condensation catalyst, metal salts such as carboxylic acid metal salts, carboxylic acid ester metal salts, carboxylic acid metal salt polymers, carboxylic acid metal salt chelates, titanate esters and titanate ester chelates can be used.
The addition amount of the condensation catalyst is preferably 0.2 to 5% by mass of the alkoxysilane compound, and more preferably 0.5 to 1% by mass.

Specific examples of carboxylic acid metal salts include stannous acetate, dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, dioctyltin dilaurate, dioctyltin dioctate, dioctyltin diacetate, stannous dioctanoate, naphthenic acid Lead, cobalt naphthenate, and iron 2-ethylhexenoate.

Specific examples of the carboxylic acid ester metal salt include dioctyltin bisoctyl thioglycolate ester salt and dioctyltin maleate ester salt.
Specific examples of the carboxylic acid metal salt polymer include dibutyltin maleate polymer and dimethyltin mercaptopropionate polymer.
Specific examples of the carboxylic acid metal salt chelate include dibutyltin bisacetylacetate and dioctyltin bisacetyllaurate.

Specific examples of the titanate ester include tetrabutyl titanate and tetranonyl titanate.
Specific examples of titanate chelate include bis (acetylacetonyl) di-propyl titanate.

When the first solution is applied to the surface of the glass substrate 21 and reacted in air at room temperature, the alkoxysilyl group and the hydroxyl group 22 on the surface of the glass substrate 21 cause a condensation reaction. A monomolecular film 23 of the first film compound having an epoxy group having a structure as shown is generated. The three single bonds extending from the oxygen atom are bonded to the surface of the glass substrate 21 or the silicon (Si) atom of the adjacent silane compound, at least one of which is a silicon atom on the surface of the glass substrate 21. Is combined with.

Since the alkoxysilyl group decomposes in the presence of moisture, the reaction is preferably performed in air with a relative humidity of 45% or less. The condensation reaction is hindered by oils and fats and moisture adhering to the surface of the glass substrate 21, so that these impurities can be removed in advance by thoroughly washing and drying the glass substrate 21. preferable.
When any of the above metal salts is used as the condensation catalyst, the time required for completion of the condensation reaction is about 2 hours.

When one or more compounds selected from the group consisting of ketimine compounds, organic acids, aldimine compounds, enamine compounds, oxazolidine compounds, and aminoalkylalkoxysilane compounds are used as the condensation catalyst instead of the above metal salts, Time can be shortened to about 1/2 to 2/3.

Alternatively, when these compounds are used as a co-catalyst and mixed with the above-described metal salt (mass ratio 1: 9 to 9: 1 can be used, preferably around 1: 1), the reaction time is further shortened. it can.

For example, when the epoxidized glass substrate 11 is produced by using H3 of Japan Epoxy Resin Co., which is a ketimine compound instead of dibutyltin diacetate as the condensation catalyst, and other conditions are the same, the epoxidized glass substrate 11 is produced. The reaction time can be reduced to about 1 hour without impairing the quality of the product.

Furthermore, when a mixture of H3 and dibutyltin diacetate from Japan Epoxy Resin Co., Ltd. (mixing ratio is 1: 1) is used as the condensation catalyst, and the other conditions are the same, the epoxidized glass substrate 11 is produced. Time can be shortened to about 20 minutes.

The ketimine compound that can be used here is not particularly limited, and examples thereof include 2,5,8-triaza-1,8-nonadiene, 3,11-dimethyl-4,7,10-triaza- 3,10-tridecadiene, 2,10-dimethyl-3,6,9-triaza-2,9-undecadiene, 2,4,12,14-tetramethyl-5,8,11-triaza-4,11-penta Decadiene, 2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene, 2,4,20,22-tetramethyl-5,12,19-triaza -4,19-trieicosadiene and the like.

Moreover, although it does not specifically limit as an organic acid which can be used, For example, a formic acid, an acetic acid, propionic acid, a butyric acid, malonic acid etc. are mentioned.

For the preparation of the first solution, an organic chlorine solvent, a hydrocarbon solvent, a fluorocarbon solvent, a silicone solvent, and a mixed solvent thereof can be used. In order to prevent hydrolysis of the alkoxysilane compound, it is preferable to remove water from the desiccant or the solvent used by distillation. Moreover, it is preferable that the boiling point of a solvent is 50-250 degreeC.

Specific usable solvents include non-aqueous petroleum naphtha, solvent naphtha, petroleum ether, petroleum benzine, isoparaffin, normal paraffin, decalin, industrial gasoline, nonane, decane, kerosene, dimethyl silicone, phenyl silicone, and alkyl-modified silicone. , Polyether silicone, dimethylformamide and the like.
Furthermore, alcohol solvents such as methanol, ethanol, propanol, or a mixture thereof can also be used.

Fluorocarbon solvents that can be used include fluorocarbon solvents, Fluorinert (manufactured by 3M, USA), Afludo (manufactured by Asahi Glass Co., Ltd.), and the like. In addition, these may be used individually by 1 type and may mix 2 or more types as long as it mixes well. Furthermore, an organic chlorine solvent such as dichloromethane or chloroform may be added.

A preferable concentration of the alkoxysilane compound in the first solution is 0.5 to 3% by mass.

After the reaction, the epoxidized glass substrate 11 whose surface is covered with the monomolecular film 23 of the first film compound is removed by washing with a solvent and removing excess alkoxysilane compound and condensation catalyst remaining on the surface as unreacted substances. Is obtained. A schematic view of the cross-sectional structure of the epoxidized glass substrate 11 produced in this way is shown in FIG.

As the cleaning solvent, any solvent that can dissolve the alkoxysilane compound can be used, but dichloromethane, chloroform, N-methylpyrrolidone, etc. that are inexpensive, have high solubility, and can be easily removed by air drying are preferable. .

After the reaction, if the produced epoxidized glass substrate 11 is left in the air without washing with a solvent, a part of the alkoxysilane compound remaining on the surface is hydrolyzed by moisture in the air, and the produced silanol groups are Causes a condensation reaction with an alkoxysilyl group. As a result, an ultrathin polymer film made of polysiloxane is formed on the surface of the epoxidized glass substrate 11. Although this polymer film is not fixed to the surface of the epoxidized glass substrate 11 by a covalent bond, since it contains an epoxy group, it is similar to the monomolecular film 23 of the first film compound with respect to 2-methylimidazole. It has the reactivity of. Therefore, even if it does not wash | clean, the manufacturing process of the solar cell 10 after the process C will not be hindered in particular.

In the present embodiment, an alkoxysilane compound having an epoxy group is used, but a halosilane compound having a halosilyl group may be used instead of the alkoxysilyl group. In this case, a condensation catalyst and a cocatalyst are not required, an alcohol solvent cannot be used, and it is more susceptible to hydrolysis than an alkoxysilane compound, so use a dry solvent in dry air (relative humidity of 30% or less). The reaction conditions (concentration of halosilane compound, reaction time, etc.) other than the necessity of performing the reaction are the same as described above.
Alternatively, an alkoxysilane compound having an amino group and an alkoxysilyl group at both ends of the linear alkylene group and represented by the following general formula (Formula 5) can also be used.

In the above formula, m represents an integer of 3 to 20, and R represents an alkyl group having 1 to 4 carbon atoms. The epoxy group may be protected with a protecting group in order to avoid side reactions with the alkoxysilyl group. The protecting group is preferably one that can be easily removed by hydrolysis or the like, and examples thereof include a ketimine derivative produced by the reaction between a ketone and an amino group.
The amino group may be a secondary amine other than the primary amine shown in Chemical Formula 5, and an alkoxysilane compound containing a functional group having an imino group such as a pyrrole group or an imidazole group may be used instead of the amino group. Can do.
In this case, examples of the alkoxysilane compound having an amino group that can be used include the compounds shown in the following (21) to (28).

(21) H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃
(22) H ₂ N (CH ₂ ) ₅ Si (OCH ₃ ) ₃
(23) H ₂ N (CH ₂ ) ₇ Si (OCH ₃ ) ₃
(24) H ₂ N (CH ₂ ) ₉ Si (OCH ₃ ) _{3
(25) H 2 N (CH} 2) 5 Si (OC 2 H 5) 3
(26) H ₂ N (CH ₂ ) ₅ Si (OC ₂ H ₅ ) ₃
(27) H ₂ N (CH ₂ ) ₇ Si (OC ₂ H ₅ ) ₃
(28) H ₂ N (CH ₂ ) ₉ Si (OC ₂ H ₅ ) ₃

Among condensation catalysts, a compound containing a tin (Sn) salt reacts with an amino group contained in an alkoxysilane derivative to generate a precipitate, and thus cannot be used as a condensation catalyst.
Therefore, when an alkoxysilane compound having an amino group is used, the same compound as that in the first solution is used alone except for a carboxylic acid tin salt, a carboxylic acid ester tin salt, a carboxylic acid tin salt polymer, and a carboxylic acid tin salt chelate. Or two or more types can be mixed and used as a condensation catalyst.
The types of cocatalysts that can be used and combinations thereof, the type of solvent, the alkoxysilane compound, the condensation catalyst, and the concentration of the cocatalyst, the reaction conditions, and the reaction time are the same as when using an alkoxysilane compound having an epoxy group. Since there is, description is abbreviate | omitted.
(End of process A)

In step B, epoxidized alumina fine particles 33 whose surfaces are covered with the monomolecular film 34 of the first film compound having an epoxy group are manufactured.
In order not to impair the light transmittance of the manufactured solar cell 10, the particle diameter of the alumina fine particles 31 used for the production of the epoxidized alumina fine particles 33 is preferably smaller than the visible light wavelength (380 to 700 nm). Specifically, the average particle size of the alumina fine particles 31 is preferably 10 to 300 nm, and more preferably 10 to 100 nm. The alumina fine particles 31 used may have a single particle size. However, when alumina fine particles having two or more different particle sizes are mixed and used, the surface of the resulting solar cell 10 has fractal properties and is repellent. It is preferable because water / oil repellent antifouling property is improved.

The second solution used for the production of the epoxidized alumina fine particles 33 includes an alkoxysilane compound having an epoxy group, a condensation catalyst for promoting the condensation reaction between the alkoxysilyl group and the hydroxyl groups 32 on the surface of the alumina fine particles 31, It is prepared by mixing with a non-aqueous organic solvent.

Regarding the types of cocatalysts that can be used for the preparation of the second solution and combinations thereof, the types of solvents, the concentration of alkoxysilane compounds, condensation catalysts, and cocatalysts, reaction conditions, and reaction time, Since it is the same as that of the preparation of a solution, detailed description is abbreviate | omitted.

When the alumina fine particles 31 are dispersed in the second solution and reacted in air at room temperature, the alkoxysilyl group and the hydroxyl groups 32 on the surface of the alumina fine particles 31 cause a condensation reaction, which is schematically shown in FIG. A monomolecular film 34 of the second film compound having a structure as shown in FIG.

About reaction time and a washing | cleaning solvent, since it is the same as that of the process A, detailed description is abbreviate | omitted. Either continuous processing or batch processing may be used for cleaning. Separation of the cleaning solvent and the epoxidized alumina fine particles 33 can be performed using any known method such as filtration, decantation, and centrifugation.

In the present embodiment, an alkoxysilane compound having an epoxy group is used. However, in Step A, when an alkoxysilane compound having an amino group and represented by the general formula (Chemical Formula 5) is used, The same compound is used in B.

In this embodiment, alumina fine particles are used as the transparent fine particles. However, the surface has active hydrogen groups that react with alkoxysilyl groups and halosilyl groups, such as hydroxyl groups and amino groups, and have translucency. Arbitrary fine particles can be used.
Examples of the transparent fine particles that can be used include other inorganic oxide-based transparent fine particles such as silica and zirconia. Further, although the abrasion resistance is slightly inferior, glass fine particles may be used. For these fine particles, at least a part of the surface may be chemically modified in advance with a hydrophobic functional group such as an alkyl group or a fluoroalkyl group.
Alternatively, if the surface has an active hydrogen group such as a hydroxyl group or an amino group, organic transparent fine particles such as acrylic resin, organic-inorganic hybrid fine particles, and the like can be used.
(End of process B)

In Step C, 2-methylimidazole is brought into contact with the surfaces of the epoxidized glass substrate 11 and the epoxidized alumina fine particles 33, respectively, and the epoxidized alumina fine particles 33 are bonded and fixed to the surface via coupling bonds. The material 41 (FIG. 4) is manufactured.
2-Methylimidazole has an amino group and an imino group which react with an epoxy group at the 1-position and 3-position, respectively, and is bonded (N-CH ₂ CH ( OH) -bond).

As a method of bringing 2-methylimidazole into contact with the surfaces of the epoxidized glass substrate 11 and the epoxidized alumina fine particles 33, for example, a solution of 2-methylimidazole is applied to the surface of the epoxidized glass substrate 11 and then heated. Then, an epoxy group and a nitrogen functional group of 2-methylimidazole (either amino group or imino group) are subjected to a coupling reaction to form a monomolecular film 14 of 2-methylimidazole, and then epoxidized on the surface The method of apply | coating the dispersion liquid of the alumina fine particle 33 is mentioned.
The coating can be performed by any method such as a doctor blade method, a dip coating method, a spin coating method, a spray method, or a screen printing method.
Alternatively, a known thin film forming method such as an LB (Langmuir-Blodget) method may be used.
After coating, it is heated again to cause a coupling reaction between the epoxy group on the surface of the epoxidized alumina fine particle 33 and the nitrogen functional group (either amino group or imino group) of 2-methylimidazole, and is formed by a coupling reaction. The alumina fine particles 31 are fixed to the surface of the glass substrate 21 through the bonding.

For the preparation of the 2-methylimidazole solution, any solvent in which 2-methylimidazole is soluble can be used, but considering the price, volatility at room temperature, toxicity, etc., isopropyl alcohol, ethanol, etc. Lower alcohol solvents are preferred. The solvent used for preparing the dispersion is preferably a lower alcohol solvent such as isopropyl alcohol and ethanol from the same viewpoint.
The addition amount of 2-methylimidazole, the concentration of the solution to be applied, the heating temperature and the heating time are appropriately adjusted according to the type of base material and fine particles used, the thickness of the fine particle film to be formed, and the like.

In the present embodiment, 2-methylimidazole is used as a coupling agent, but any imidazole derivative represented by the following chemical formula 7 can be used. Alternatively, an imidazole-metal complex may be used.

Specific examples of the imidazole derivative represented by Chemical Formula 7 include those shown in the following (31) to (38).
(31) 2-Methylimidazole (R ₂ = Me, R ₄ = R ₅ = H)
(32) 2-Undecylimidazole (R ₂ = C ₁₁ H ₂₃ , R ₄ = R ₅ = H)
(33) 2-Pentadecylimidazole (R ₂ = C ₁₅ H ₃₁ , R ₄ = R ₅ = H)
(34) 2-methyl-4-ethylimidazole _{(R 2 = Me, R 4} = Et, R 5 = H)
(35) 2-Phenylimidazole (R ₂ = Ph, R ₄ = R ₅ = H)
(36) 2-phenyl-4-ethylimidazole _{(R 2 = Ph, R 4} = Et, R 5 = H)
(37) 2-phenyl-4-methyl-5-hydroxymethylimidazole _{(R 2 = Ph, R 4} = Me, R 5 = CH 2 OH)
(38) 2-Phenyl-4,5-bis (hydroxymethyl) imidazole (R ₂ = Ph, R ₄ = R ₅ = CH ₂ OH)
Me, Et, and Ph represent a methyl group, an ethyl group, and a phenyl group, respectively.

In addition, compounds such as acid anhydrides such as phthalic anhydride and maleic anhydride, and phenol derivatives such as dicyandiamide and novolak, which are used as a curing agent for epoxy resins, may be used as a coupling agent. In this case, an imidazole derivative may be used as a catalyst in order to accelerate the coupling reaction.

In this embodiment, the case where a film compound having an epoxy group is used is described. However, when a film compound having an amino group or an imino group is used in steps A and B, the first cup is used. A coupling agent having 2 or 3 or more epoxy groups or 2 or 3 or more isocyanate groups is used as the ring reactive group. In this case, an NH—CONH bond is formed by the coupling reaction. Specific examples of the compound having an isocyanate group include hexamethylene-1,6-diisocyanate, toluene-2,6-diisocyanate, and toluene-2,4-diisocyanate.
The addition amount of these diisocyanate compounds is preferably 5 to 15% by weight of the epoxidized alumina fine particles as in the case of 2-methylimidazole. In this case, examples of the solvent that can be used for the production of the film precursor include aromatic organic solvents such as xylene.
Moreover, as a coupling agent, the compound which has 2 or 3 or more epoxy groups, such as ethylene glycol diglycidyl ether, can also be used.
(End of process C)

In step D, a third solution containing a halosilane compound having a fluorocarbon group and a halosilyl group at both ends of the molecule is brought into contact with the surface of the epoxidized alumina fine particle 33 exposed to the atmosphere, and epoxy groups and A bond is formed with the halosilyl group, and the water-repellent monomolecular film 13 is further formed on the surface exposed to the atmosphere of the epoxidized alumina fine particles 33 to produce the water-repellent glass plate 24.

The third solution used for manufacturing the water-repellent glass plate 24 is a mixture of a halosilane compound containing a halosilyl group and a fluorocarbon group that react with an epoxy group to form a covalent bond, and a non-aqueous organic solvent. It is prepared by.

Examples of the halosilane compound containing a fluorocarbon group include halosilane compounds represented by the following general formula (Formula 8).

In the above formula, m represents an integer of 0 to 20, n represents an integer of 0 to 9, and X represents any of chlorine, bromine, and iodine.
Y represents either (CH ₂ ) _k (k represents an integer of 1 to 3) or a single bond, and Z represents O (ether oxygen), COO, Si (CH ₃ ) ₂ , and single Represents one of the bonds.

Examples of the halosilane compound containing a fluorocarbon group that can be used in Step D include the compounds shown in the following (41) to (46).

(41) CF ₃ CH ₂ O (CH ₂ ) ₁₅ SiCl _{3
(42) CF 3 (CH 2} ) 3 Si (CH 3) 2 (CH 2) 15 SiCl 3
(43) CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (CH ₃ ) ₂ (CH ₂ ) ₉ SiCl ₃
(44) CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (CH ₃ ) ₂ (CH ₂ ) ₉ SiCl ₃
(45) CF ₃ COO (CH ₂ ) ₁₅ SiCl ₃
(46) CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ SiCl ₃

Since the halosilane compound is used for the preparation of the third solution, a condensation catalyst and a cocatalyst are unnecessary, an alcohol solvent cannot be used, and it is more susceptible to hydrolysis than an alkoxysilane compound. The reaction is different from the steps A and B in that the reaction is performed in dry air (relative humidity 30% or less), but the other reaction conditions (concentration of halosilane compound, reaction time, etc.) are the same as those in steps A and B. Detailed description is omitted.

Since the film thickness of the water repellent monomolecular film 13 is only about 1 nm, the unevenness of 10 nm or more formed on the surface of the fine particle fixed glass substrate 41 is hardly damaged. In addition, due to this unevenness effect (so-called “lotus leaf effect”), the apparent surface energy of the light incident side surface of the solar cell 10 can be reduced, and the water droplet contact angle is 140 degrees or more (in this embodiment, 150 degrees). It is possible to achieve super water repellency.

In addition, since the alumina fine particles 31 having higher hardness than glass are fixed on the surface of the glass substrate 21 of the solar cell 10, the wear resistance is also greatly improved.
Further, in the solar cell 10, since the thickness of the coating including the alumina fine particles 31 and the water repellent monomolecular film 13 formed on the surface of the glass substrate 21 is about 100 nm as a whole, the transparency of the glass substrate 21. Will not be damaged.

After the reaction, when the produced solar cell 10 is left in the air without being washed with a solvent, a part of the alkoxysilane compound remaining on the surface is hydrolyzed by moisture in the air, and the produced silanol group is converted into a halosilyl group. Causes a condensation reaction. As a result, an ultrathin polymer film made of polysiloxane is formed on the surface of the solar cell 10. Unlike a monomolecular film, this polymer film is not necessarily fixed to the surface of the solar cell 10 by covalent bonds, but has a fluorocarbon group, so that it has water and oil repellency and antifouling properties. have. Therefore, it can be used as the solar cell 10 in this state as long as the durability is somewhat inferior.

In this embodiment, the case of using a film compound having an epoxy group is described. However, in the case of using a film compound having an amino group or an imino group in Steps A and B, in addition to the halosilane compound, For example, the alkoxysilane compound containing the fluorocarbon group shown to following (51)-(62) can be used.

(51) CF ₃ CH ₂ O (CH ₂ ) ₁₅ Si (OCH ₃ ) _{3
(52) CF 3 (CH 2} ) 3 Si (CH 3) 2 (CH 2) 15 Si (OCH 3) 3
_{(53) CF 3 (CF 2} ) 5 (CH 2) 2 Si (CH 3) 2 (CH 2) 9 Si (OCH 3) 3
_{(54) CF 3 (CF 2} ) 7 (CH 2) 2 Si (CH 3) 2 (CH 2) 9 Si (OCH 3) 3
(55) CF ₃ COO (CH ₂ ) ₁₅ Si (OCH ₃ ) ₃
(56) CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (OCH ₃ ) _{3
(57) CF 3 CH 2 O} (CH 2) 15 Si (OC 2 H 5) 3
_{(58) CF 3 (CH 2} ) 3 Si (CH 3) 2 (CH 2) 15 Si (OC 2 H 5) 3
_{(59) CF 3 (CF 2} ) 5 (CH 2) 2 Si (CH 3) 2 (CH 2) 9 Si (OC 2 H 5) 3
_{(60) CF 3 (CF 2} ) 7 (CH 2) 2 Si (CH 3) 2 (CH 2) 9 Si (OC 2 H 5) 3
(61) CF ₃ COO (CH ₂ ) ₁₅ Si (OC ₂ H ₅ ) ₃
(62) CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃

In this case, the types of cocatalysts that can be used for the preparation of the third solution and their combinations, the types of solvents, the concentration of alkoxysilane compounds, the condensation catalyst, and the cocatalyst, the reaction conditions, and the reaction time are tin. Except for the point that a compound containing (Sn) cannot be used as a condensation catalyst, it is the same as Steps A and B, and thus detailed description thereof is omitted.
(End of process D)

The solar cell 10 is manufactured by forming the solar cell layer 60 on the back side of the water-repellent glass plate 24 thus obtained.
First, the silver paste comb-shaped electrode 51 is formed on the back surface of the water-repellent glass plate 24 using a printing method, and then the n-type semiconductor layer 52 and the p-type semiconductor layer 53 are sequentially formed by vapor deposition. Furthermore, the solar cell layer 60 is formed by vapor-depositing an aluminum vapor deposition back electrode 54 that also serves as a reflective film thereon.
Examples of semiconductors that can be used to form the n-type semiconductor layer 52 and the p-type semiconductor layer 53 include polycrystalline silicon, amorphous silicon, chalcopyrite-based compound semiconductors, and the like.
Examples of a vapor deposition method that can be used for forming the n-type semiconductor layer 52, the p-type semiconductor layer 53, and the aluminum vapor deposition back electrode 54 include a PVD method and a CVD method.

As a solar cell according to the present embodiment, a pn junction solar cell has been described by way of example, the intrinsic (intrinsic) semiconductor layer containing no impurities between the n-type semiconductor layer and the p-type semiconductor layer The formed pin junction solar cell may be used.

The solar cell 10 has a water droplet contact angle of 150 degrees or more and 180 degrees or less.
From the experimental results of examining the relationship between the contact angle to the water droplet on the water repellent surface and the falling angle using water droplets of different volumes (0.02 to 0.08 mL), when the water droplet contact angle is 150 degrees or more, It is known that the falling angle is 15 degrees or less regardless of the volume. Therefore, it can be seen that in the solar cell 10, most of the water droplets adhering to the surface of the water-repellent glass plate 24 cannot fall on the surface and fall down.
In addition, the water-repellent alumina fine particles 12 fixed on the surface of the glass substrate 21 reduce the reflectance of incident light by gently changing the refractive index, so that the n-type semiconductor layer 52, the p-type semiconductor layer 53, The light transmittance to the junction surface (pn junction surface) can be improved.

The solar cell 10 is excellent in durability such as abrasion resistance and weather resistance, water droplet water separation (sliding property), and antifouling property, and is suitably used for a solar power generation panel or the like permanently installed outdoors. be able to.

Although the solar cell and the manufacturing method thereof have been described in the present embodiment, a solar water heater, a greenhouse, or the like using a water-repellent glass plate manufactured by a method including steps A to D as a light incident side transparent substrate. The present invention is also applied to the solar energy utilization apparatus.

Examples carried out for confirming the effects of the present invention will be described below, but the present invention is not limited to these examples.
In this embodiment, a solar cell will be described as a representative example.

Example 1
(1) Preparation of Epoxidized Glass Substrate A light incident side transparent substrate (made of glass; hereinafter referred to as “glass substrate”) of a solar cell was prepared, washed well and dried.
0.99 parts by weight of 3-glycidyloxypropyltrimethoxysilane (Chemical 9; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.01 parts by weight of dibutyltin bisacetylacetonate (condensation catalyst) were weighed, and this was 100 parts by weight. A first solution was prepared by dissolving in hexamethyldisiloxane solvent.

The first solution thus obtained was applied to the surface of a glass substrate and reacted in air (relative humidity 45%) for about 2 hours.
Thereafter, the mixture was washed with chloroform to remove excess alkoxysilane compound and dibutyltin bisacetylacetonate.

(2) Preparation of epoxidized alumina fine particles 3-Glycidyloxypropyltrimethoxysilane (Chemical Formula 9, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.99 parts by weight and dibutyltin bisacetylacetonate (condensation catalyst) 0.01 parts by weight Weighed and dissolved in 100 parts by weight of hexamethyldisiloxane solvent to prepare a second solution.

The dried alumina fine particles (average particle size 200 nm) were mixed and stirred in the second solution thus obtained and reacted in the air (relative humidity 45%) for about 2 hours.
Thereafter, the mixture was washed with chloroform to remove excess alkoxysilane compound and dibutyltin bisacetylacetonate.

(3) Preparation of fine particle fixed glass base material When an ethanol solution of 2-methylimidazole is applied to the surface of the epoxidized glass base material prepared in (1) and heated at 100 ° C, the epoxy group and 2-methylimidazole A reactive glass substrate was obtained by reaction with an amino group. Excess 2-methylimidazole was removed by washing with ethanol.
The ethanol dispersion of the epoxidized alumina fine particles prepared in (2) was applied to the surface of the epoxidized glass base material, the surface of which was further coated with the film formed by 2-methylimidazole, Heated at 100 ° C. After the reaction, it was washed with water to remove excess epoxidized alumina fine particles.

(4) Formation of water-repellent monomolecular film (heptadecafluoro-1,1,2,2-tetrahydrodecyl) 1 part by weight of trichlorosilane (Chemical Formula 10) is dissolved in 100 parts by weight of dehydrated nonane, A solution was prepared.
The third solution was applied to the surface of the fine particle fixed glass substrate prepared in (3) in dry air having a relative humidity of 30% or less and reacted. After the reaction, it was washed with a fluorocarbon solvent to remove the unreacted trichlorosilane compound.

(5) Formation of solar cell After applying silver paste to the back surface of the water-repellent glass plate obtained in (4) using a printing method, the coating film of silver paste was cured to form a silver paste comb-shaped electrode. . Next, an n-type amorphous silicon layer and a p-type amorphous silicon layer were sequentially formed by a CVD method. Furthermore, aluminum was vapor-deposited thereon to form a back electrode, and a solar cell layer was formed on the back surface of the water-repellent glass plate.
Here, the deposition of amorphous silicon and the deposition of the aluminum electrode were carried out at 450 ° C. or lower, so that peeling of the alumina fine particles fixed on the surface of the water-repellent glass plate and destruction of the water-repellent monomolecular film did not occur. .

The apparent water droplet contact angle of the solar cell thus obtained was measured and found to be about 150 degrees.
For comparison, a water-repellent monomolecular film was formed on the surface of a glass substrate on which alumina fine particles were not fixed using the same method as in (4), and the water droplet contact angle was measured. Was about 115 degrees.

(Example 2)
Example 1 (1) except that a monomolecular film is formed on the surface of the glass substrate and alumina fine particles using an alkoxysilane compound having an amino group, and hexamethylene-1,6-diisocyanate is used as a coupling agent. The water-repellent glass plate could be produced by the same method as in (4) to (4).
Then, the solar cell was able to be manufactured using the same method as (5) of Example 1.

It is explanatory drawing which represented typically the cross-section of the solar cell which is a solar energy utilization apparatus which concerns on one embodiment of this invention. It is the schematic diagram expanded to the molecular level in order to demonstrate the process of manufacturing an epoxidized glass base material in the manufacturing method of the solar cell, (a) is the cross-sectional structure of the glass base material surface before reaction, (b) Represents a cross-sectional structure of an epoxidized glass substrate on which a monomolecular film having an epoxy group is formed. In the manufacturing method of the solar cell, in order to explain the process of producing epoxidized alumina fine particles, it is a schematic diagram enlarged to the molecular level, (a) is a cross-sectional structure of alumina fine particles before reaction, (b) is an epoxy group Each represents a cross-sectional structure of an epoxidized alumina fine particle on which a monomolecular film having s is formed. In the manufacturing method of the said solar cell, in order to demonstrate the process of manufacturing a microparticle fixed glass base material, it is the schematic diagram which expanded the cross-sectional structure to the molecular level.

Explanation of symbols

10: solar cell, 11: epoxidized glass substrate, 12: water-repellent alumina fine particles, 13: water-repellent monomolecular film, 14: monomolecular film of 2-methylimidazole, 21: glass substrate, 22: hydroxyl group, 23: Monomolecular film of the first film compound, 24: Water repellent glass plate, 31: Alumina fine particles, 32: Hydroxyl group, 33: Epoxidized alumina fine particles, 34: Monomolecular film of the second film compound, 41: Fine particle fixed glass substrate, 51: silver paste comb electrode, 52: n-type semiconductor layer, 53: p-type semiconductor layer, 54: aluminum vapor deposition back electrode. 60: Solar cell layer

Claims (21)

On the surface of the light incident side transparent substrate coated with the film formed by the first film compound having the first functional group which is an epoxy group or amino group, the surface of the surface is formed by the film formed by the first film compound. When the first functional group is an epoxy group, the water-repellent transparent fine particles coated at least in part are each one or more amino groups and imino groups, and when the first functional group is an amino group, N—CH ₂ CH (OH) bond or NH formed by a coupling reaction between the first functional group and a coupling agent having two or more coupling groups which are two or more epoxy groups or isocyanate groups A solar energy utilization device that is fixed through a -CONH bond. 2. The solar energy utilization device according to claim 1, wherein the first film compound is covalently bonded to the surface of the light incident side transparent substrate and the surface of the transparent fine particle through Si, respectively. To use solar energy. 3. The solar energy utilization device according to claim 1, wherein the first film compound is either one of a film formed on the surface of the light incident side transparent base material and the surface of the transparent fine particles, or A solar energy utilization device characterized in that both are monomolecular films. In the solar energy utilization apparatus of any one of Claims 1-3, the surface of the part exposed to the air | atmosphere side of the said water-repellent transparent fine particle forms the 3rd film | membrane compound which has a water-repellent functional group. A solar energy utilization device, further comprising a water repellent coating. In the solar energy utilization system according to claim 4, wherein, the solar energy utilization system in which the water-repellent functional groups characterized in that it comprises a group -CF _3. 6. The solar energy utilization device according to claim 4, wherein the water-repellent coating formed by the third film compound is a monomolecular film. 7. The solar energy utilization apparatus according to any one of claims 1 to 6, wherein the transparent fine particles are selected from the group consisting of translucent silica, alumina, and zirconia. Use device. The solar energy utilization apparatus of any one of Claims 1-7 WHEREIN: The average particle diameter of the said transparent fine particles is 10 nm or more and 300 nm or less, The solar energy utilization apparatus characterized by the above-mentioned. The solar energy utilization apparatus of any one of Claims 1-8 WHEREIN: The contact angle with respect to water is 150 to 180 degree | times, The solar energy utilization apparatus characterized by the above-mentioned. A first solution containing a first film compound having a first functional group that is an epoxy group or an amino group at each end of the molecule and a first bonding group is applied to the light incident side surface of the light incident side transparent substrate. A coated light incident side having a coating formed by the first film compound on the light incident side surface, wherein the first bonding group and the surface of the light incident side transparent base material are contacted to form a bond; Step A for preparing a transparent substrate;
Forming the first film compound by bringing the second solution containing the first film compound into contact with the surface of the transparent fine particles to form a bond between the first binding group and the surface of the transparent fine particle. A step B of preparing coated transparent fine particles in which at least a part of the surface of the transparent fine particles is coated with a coating film;
When the first functional group is an epoxy group, one or more amino groups and imino groups, respectively, and when the first functional group is an amino group, two or more epoxy groups or isocyanate groups are present. A coupling agent having a coupling group is brought into contact with the surface of the light incident side of the coated light incident side transparent substrate and the surface of the coated transparent fine particles, respectively, and the first functional group and the coupling reactive group And a step C of forming a N—CH ₂ CH (OH) bond or a NH—CONH bond by a coupling reaction, and bonding and fixing the coated transparent fine particles to the light incident side surface of the coated light incident side transparent substrate. The manufacturing method of the solar energy utilization apparatus characterized by the above-mentioned. 11. The method for manufacturing a solar energy utilization device according to claim 10, wherein unreacted substances are washed and removed after one or both of the steps A and B. The method for manufacturing a solar energy utilization device according to claim 10 or 11, wherein one or both of the first film compounds contained in the first and second solutions are alkoxysilane compounds. A method for manufacturing a solar energy utilization device. In the manufacturing method of the solar energy utilization apparatus of any one of Claims 10-12, either one or both of the said 1st film | membrane compounds each contained in the said 1st and 2nd solution are halosilane compounds. A method for manufacturing a solar energy utilization device. 13. The method for manufacturing a solar energy utilization device according to claim 12, wherein the first and second solutions containing the alkoxysilane compound further include a carboxylic acid metal salt, a carboxylic acid ester metal salt, and a carboxylic acid metal salt. The manufacturing method of the solar energy utilization apparatus characterized by including the 1 or 2 or more compound selected from the group which consists of a polymer, carboxylate metal salt chelate, titanate ester, and titanate ester chelate. The method for manufacturing a solar energy utilization device according to any one of claims 12 and 14, wherein the first and second solutions containing the alkoxysilane compound further include a ketimine compound, an organic acid, and an aldimine. The manufacturing method of the solar energy utilization apparatus characterized by including the 1 or 2 or more compound selected from the group which consists of a compound, an enamine compound, an oxazolidine compound, and an aminoalkyl alkoxysilane compound. In the manufacturing method of the solar energy utilization apparatus of any one of Claims 10-15, on the surface exposed to the air | atmosphere of the said covering transparent fine particle after the said process C, a water-repellent functional group on both ends of a molecule | numerator And a third solution containing a second film compound each having a second bonding group that reacts with the first functional group, and the second bonding group and the first functional group A method of manufacturing a solar energy utilization device, further comprising a step D of forming a water repellent film formed by the second film compound on a surface exposed to the atmosphere side by forming a bond between them. 17. The method for manufacturing a solar energy utilization device according to claim 16, wherein after the step D, the unreacted second film compound is washed and removed. 18. The method of manufacturing a solar energy utilization device according to claim 16, wherein the second film compound contained in the third solution is an alkoxysilane compound containing a fluorocarbon group. A method for manufacturing a solar energy utilization device. 18. The method of manufacturing a solar energy utilization device according to claim 16, wherein the second film compound contained in the third solution is a halosilane compound containing a fluorocarbon group. A method for manufacturing a solar energy utilization device. The method of manufacturing a solar energy utilization device according to claim 18, wherein the third solution further includes a carboxylic acid metal salt, a carboxylic acid ester metal salt, a carboxylic acid metal salt polymer, a carboxylic acid metal salt chelate, a titanate ester, and The manufacturing method of the solar energy utilization apparatus characterized by including the 1 or 2 or more compound selected from the group which consists of titanate ester chelate. 21. The method for manufacturing a solar energy utilization device according to claim 18, wherein the third solution further includes a ketimine compound, an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxy. The manufacturing method of the solar energy utilization apparatus characterized by including the 1 or 2 or more compound selected from the group which consists of a silane compound.

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