CN102097513A

CN102097513A - Conductive reflective film and producing method thereof

Info

Publication number: CN102097513A
Application number: CN2010105295203A
Authority: CN
Inventors: 山崎和彦; 荒井将英; 林年治
Original assignee: Mitsubishi Materials Corp
Current assignee: Mitsubishi Materials Corp
Priority date: 2009-10-23
Filing date: 2010-10-22
Publication date: 2011-06-15

Abstract

The invention provides a conductive reflective film and a producing method thereof. The conductive reflective film does not need a vacuum process, has a high reflectivity from the side of a base material, and shows a low resistivity equal to that of the electrode body used as solar energy battery. The conductive reflective film on a transparent conductive film formed on a photoelectric conversion layer of a sheathing-type thin film solar cell is coated on the transparent conductive film with compositions having metallic nano particles in a manner of wet type coating method. The base materials coated with the films are sintered, thereby the reflective film is formed and a part of the interface of the reflective film and the transparent conductive film is provided with an air layer. The total area of the generated air layer with respect to the reflective film area is within 5-70%.

Description

Conductive reflecting film and manufacture method thereof

Technical field

The present invention relates to a kind of conductive reflecting film and manufacture method thereof, this conductive reflecting film forms by composition and the sintering that the coating of wet type rubbing method comprises metal nanoparticle, reflectivity height when the base material side is measured, and the low-resistivity of demonstration and main body same degree.

Background technology

At present, from the position of environmental protection, the research and development of green energy resource develop.Wherein solar cell is unlimited as the sunlight of its resource, and nuisanceless etc., therefore receive publicity.In the past, when the solar power generation that carries out according to solar cell, used following block solar cell: make the main body shape crystal of monocrystalline silicon or polysilicon, it is carried out cut and uses as the thick plate-like semiconductor always.But the crystal growth that is used in the above-mentioned silicon wafer of block solar cell needs big energy and time, and also needs complicated step in follow-up manufacturing process, therefore produces efficient in batches and is difficult to improve, and is difficult to provide the solar cell of low price.

On the other hand, with thickness the semiconductor layer of the amorphous silicon etc. below several microns uses as photoelectric conversion layer, so-called thin-film semiconductor solar cell (hereinafter referred to as thin-film solar cells), as long as on the substrate of cheapnesss such as glass or stainless steel, only form the required semiconductor layer that becomes photoelectric conversion layer.Therefore, this thin-film solar cells be slim and in light weight, cheap for manufacturing cost, realize large tracts of landization easily, therefore can think becomes the main flow of solar cell from now on.

Thin-film solar cells is according to its structure, cladding plate (ス one パ one ストレ one ト) type or substrate (サ Block ストレ one ト) type are arranged, from the cladding plate type solar cell of light-transmitting substrate side incident light, adopt structure usually with the order formation of substrate-transparency electrode-photoelectric conversion layer-backplate.In the cladding plate type solar cell that photoelectric conversion layer is formed by the silicon based material, for example studying the structure that forms by the order that adopts with transparency electrode, amorphous silicon, polysilicon, backplate and improving generating efficiency (for example with reference to non-patent literature 1.)。In the structure shown in this non-patent literature 1, amorphous silicon or polysilicon constitute photoelectric conversion layer.

Especially when photoelectric conversion layer constitutes solar cell by the silicon based material, the absorptivity of the photoelectric conversion layer that is formed by above-mentioned material is less, therefore photoelectric conversion layer is in the micron-sized thickness of number, and the part of incident light sees through photoelectric conversion layer, and the light that sees through does not have effect to generating.Therefore, common following carrying out: backplate perhaps forms reflectance coating on the electrode overleaf as reflectance coating, makes and can't all absorb, and reflect by reflectance coating through the light of photoelectric conversion layer, returns photoelectric conversion layer once more, improves generating efficiency with this.

Up to now, in the exploitation about thin-film solar cells, electrode or reflectance coating become embrane method to form by the sputtering method equal vacuum.But the maintenance of large-scale vacuum film formation device and running need bigger cost usually.Therefore, studied by wet type for these formation methods and to become embrane method to replace the vacuum film formation method, become embrane method by changing to wet type, expectation significantly improves operating cost.

As the example of the conductive reflecting film that becomes embrane method to form by wet type, the reflectance coating that discloses the rear side formation of using electroless plating method to be formed on photo-electric conversion element is (for example with reference to patent documentation 1.)。In the method shown in this patent documentation 1, put down in writing and to have formed the content that reflectance coating is sought productive raising by using electroless plating method.Specifically; the face side that is printed on substrate by whole face becomes the etchant resist of electroplating film; then; use adds the solution of HF gained in non-conductor usefulness pretreatment liquid with the ratio of 2～4 quality %; rear side to substrate is implemented pre-treatment; use electroless plating liquid, form the reflector that constitutes by about 3 μ m plated copper films.Then, in solvent, substrate is carried out ultrasonic waves for cleaning and removes etchant resist, form photo-electric conversion element thus.

But; electroless plating method shown in the above-mentioned patent documentation 1 is because through following operation; promptly form electroplating film in face side; with HF solution one side of carrying out electroplating processes is carried out pre-treatment then; be immersed in the operation of electroless plating liquid etc. then; therefore, except numerous and diverse operation, can also be contemplated to the generation of waste liquid.

In addition, as easier method, disclose following method, i.e. coating makes super fine grain of metal be scattered in solution in the organic system solvent, carries out the method for sintering (for example with reference to patent documentation 2 with 100～250 ℃ low temperature.)。According to the method shown in the above-mentioned patent documentation 2, do not use high vacuum technology can form all high large tracts of land of reflectivity, conductance and even metal electrode.

But in the metal film that is obtained by the method shown in above-mentioned patent documentation 2, the reflectivity of base material side is compared the tendency that decline is arranged with the reflectivity that exposes the face side that is equivalent to opposite sides.This is because when coating usually, the ultramicronized dispersion liquid formation of sintering metal metal film, producing average diameter between the base material of metal film and formation film is the following pore of 100nm.If between metal film and base material, produce pore, then can be presumed as follows situation: the light that enters pore inside interreflection and decaying in pore, the reverberation that perhaps arrives the base material side is when the incidence angle with respect to substrate surface increases, in all ratio increases of reflection of the interface of low refractive index dielectric (air of pore)/high refractive index medium (base material), also cause optical attenuation according to its ratio.

Patent documentation 1: Japan Patent discloses flat 05-95127 communique (paragraph of detailed description of the invention [0015], [0020] and [0021])

Patent documentation 2: Japan Patent discloses flat 09-246577 communique (paragraph of detailed description of the invention [0035])

Non-patent literature 1: people such as Shozo Yanagida work, " film too the most preceding Line of Yang Electricity Chi development～high efficiency mass production popularize Cu Jin To けて～(the exploitation forefront of thin-film solar cells～towards high efficiency or batchs processization or promotion universal～) ", NTS Co., LTD, in March, 2005, P.113 Fig. 1 (a)

Dispersion liquid by coating, sintering metal nano particle is when forming reflectance coating, if estimate reflectivity from light transmission base material sides such as glass, then with from being equivalent to exposing of opposite sides compares when the face side is estimated reflectivity, finds that reflectivity significantly descends.

Summary of the invention

The object of the present invention is to provide a kind of needing no vacuum technology,, and show conductive reflecting film and manufacture method thereof with the low-resistivity of the main body same degree that also can be used as the use of used for solar batteries electrode from the reflectivity height of base material side.

Other purposes of the present invention are to provide a kind of vacuum vapour deposition or sputtering method equal vacuum technology got rid of as far as possible, make the method for the conductive reflecting film of cladding plate type used for solar batteries more at an easy rate by using the wet type rubbing method.

Present inventors further investigate the character of the conductive reflecting film that obtains with coating process in cladding plate type thin-film solar cells, it found that following content and has finished the present invention, promptly by coating metal nanoparticulate dispersion on base material, make a part of emersion of particle in filming with certain certain above specific programming rate heat-agglomerating, form air layer with certain certain gross area in a part with the interface of nesa coating; And this air layer produces according to this air layer to increase reflecting effect with a large amount of average diameters that occur are that pore below the 100nm is different at the interface in coating process in the past, compares reflectivity with reflectance coating in the past and increases; Its result obtains high conversion efficiency by carry this reflectance coating at solar cell.

The 1st viewpoint of the present invention, promptly be formed at the conductive reflecting film on the nesa coating of film forming on the photoelectric conversion layer of cladding plate type thin-film solar cells, it is characterized in that, the composition that will comprise metal nanoparticle by the wet type rubbing method is coated on the nesa coating, sintering has this base material of filming, form reflectance coating thus so that the part at the interface of this reflectance coating and nesa coating has air layer, the air layer of generation with respect to the gross area of reflectance coating area in 5～70% scopes.

The 2nd viewpoint of the present invention promptly based on the invention of the 1st viewpoint, is further characterized in that, the height of air layer is in 5～200nm scope, and the width of air layer is in 10～300nm scope.

The 3rd viewpoint of the present invention, promptly based on the invention of the 1st or the 2nd viewpoint, be further characterized in that, comprise the material more than a kind or 2 kinds that is selected from the group that copolymer and water-soluble cellulose by polyvinylpyrrolidone, polyvinylpyrrolidone constitute in the reflectance coating.

The 4th viewpoint of the present invention promptly based on the invention of the 1st to the 3rd viewpoint, is further characterized in that, in the reflectance coating in the contained metallic element ratio of silver be more than the 75 quality %.

The 5th viewpoint of the present invention based on the invention of the 1st to the 4th viewpoint, is further characterized in that promptly the thickness of reflectance coating is in 0.05～2.0 mu m range.

The 6th viewpoint of the present invention promptly based on the invention of the 1st to the 5th viewpoint, is further characterized in that, with regard to metal nanoparticle contained in the reflectance coating, particle diameter is counted more than 70% with number average at the particle of 10～50nm scope.

The 7th viewpoint of the present invention, promptly based on the invention of the 1st to the 6th viewpoint, be further characterized in that, comprise of the coating of the composition of metal nanoparticle according to the wet type rubbing method, be to be coated with into thickness behind the sintering to become coating in 0.05～2.0 mu m range, the sintering with the base material of filming is to keep carrying out in 10～60 minutes under 100～300 ℃/minute, 130～400 ℃ temperature at programming rate.

The 8th viewpoint of the present invention, promptly based on the invention of the 1st to the 7th viewpoint, be further characterized in that the wet type rubbing method is any one of spraying process, distribution rubbing method, spin-coating method, knife coating, slot coated method, ink-jet application method, silk screen print method, hectographic printing method or die rubbing method.

The 9th viewpoint of the present invention; promptly based on the invention of the 1st to the 8th viewpoint; be further characterized in that; the ratio of the composition that comprises metal nanoparticle by silver in the metallic element is that the metal nanoparticle more than the 75 quality % is dispersed in the decentralized medium and prepares; metal nanoparticle by carbon skeleton be the protective agent of organic molecule main chain of carbon number 1～3 by chemical modification, it is the metal nanoparticle of 10～50nm scope that metal nanoparticle contains the primary particle diameter of counting more than 70% with number average.

The 10th viewpoint of the present invention, promptly based on the invention of the 1st to the 9th viewpoint, be further characterized in that, base material is any one of glass, the pottery that comprises transparent conductive material or the light-transmitting substrate that is made of macromolecular material, or is selected from the light transmission lamination body more than 2 kinds in the group that is made of glass, the pottery that comprises transparent conductive material, macromolecular material and silicon.

The 11st viewpoint of the present invention, promptly based on the invention of the 1st to the 10th viewpoint, be further characterized in that the composition that contains metal nanoparticle further comprises the additive more than a kind or 2 kinds that is selected from the group that is made of organic polymer, metal oxide, metal hydroxides, organo-metallic compound and silicone oil.

The 12nd viewpoint of the present invention promptly based on the invention of the 11st viewpoint, is further characterized in that, organic polymer is the material more than a kind or 2 kinds that is selected from the group that copolymer and water-soluble cellulose by polyvinylpyrrolidone, polyvinylpyrrolidone constitute.

The 13rd viewpoint of the present invention, promptly based on the invention of the 11st viewpoint, be further characterized in that metal oxide is to comprise at least a kind oxide or the composite oxides that are selected from the group that is made of aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.

The 14th viewpoint of the present invention, promptly based on the invention of the 11st viewpoint, be further characterized in that metal hydroxides is to comprise at least a kind the hydroxide that is selected from the group that is made of aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.

The 15th viewpoint of the present invention, promptly based on the invention of the 11st viewpoint, be further characterized in that organo-metallic compound is to comprise at least a kind metallic soap, metal complex or the metal alkoxide that is selected from the group that is made of silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin.

The 16th viewpoint of the present invention promptly based on the invention of the 1st to the 15th viewpoint, is further characterized in that, contains water and the alcohols more than the 2 quality % more than the 1 quality % as decentralized medium.

The 17th viewpoint of the present invention, it is the manufacture method of conductive reflecting film, it is characterized in that, the composition that will comprise metal nanoparticle by the wet type rubbing method is coated on the nesa coating of film forming on the photoelectric conversion layer of cladding plate type thin-film solar cells, to have the base material of filming with 100～300 ℃ of/minute intensifications, under 130～400 ℃ of temperature, kept 10～60 minutes and sintering, form film thus so that this film has air layer in the part with the interface of nesa coating, the gross area with respect to the reflectance coating area of the air layer of generation is located in 5～70% scopes.

The 18th viewpoint of the present invention; promptly based on the invention of the 17th viewpoint; be further characterized in that; the composition that comprises metal nanoparticle is that metal nanoparticle more than the 75 quality % is dispersed in the decentralized medium and prepares according to the ratio of silver in the metallic element; metal nanoparticle is that the protective agent of organic molecule main chain of carbon number 1～3 is by chemical modification by carbon skeleton; it is the metal nanoparticle of 10～50nm scope that metal nanoparticle contains the primary particle diameter of counting more than 70% with number average, by the wet type rubbing method composition coating is become in 0.05～2.0 mu m range for the thickness behind the sintering on nesa coating.

The 19th viewpoint of the present invention, it is the composite membrane of cladding plate type used for solar batteries, it is characterized in that, on the photoelectric conversion layer of cladding plate type solar cell, form nesa coating, on this nesa coating, form conductive reflecting film, or pass through the conductive reflecting film of the manufacture method manufacturing of conductive reflecting film based on the 1st to the 18th viewpoint.

The 20th viewpoint of the present invention, promptly layered product uses the conductive reflecting film based on the 1st to the 19th viewpoint, or passes through the conductive reflecting film of the manufacture method manufacturing of conductive reflecting film.

The 21st viewpoint of the present invention, i.e. solar cell uses conductive reflecting film, layered product or the conductive reflecting film of making by the manufacture method of conductive reflecting film based on the 1st to the 20th viewpoint, layered product as electrode.

The 22nd viewpoint of the present invention, i.e. solar cell uses conductive reflecting film based on the 1st to the 21st viewpoint as electrode.

The invention effect

As mentioned above, according to the present invention, be formed at the conductive reflecting film on the nesa coating of film forming on the photoelectric conversion layer of cladding plate type solar cell, the composition that will comprise metal nanoparticle by the wet type rubbing method is coated on the nesa coating, sintering has this base material of filming, form thus in a part and have air layer with the interface of nesa coating, the air layer of generation with respect to the gross area of reflectance coating area in 5～70% scopes.In the reflection at the interface of nesa coating and conductive reflecting film, though reflectivity height but the decay of light is big, only can't obtain sufficient reflectivity with reverberation composition according to conductive reflecting film, and, when average diameter occurring and be the following pore of 100nm, owing to the light that enters pore inside interreflection in pore is decayed, the reverberation that perhaps arrives the base material side is when the incidence angle with respect to substrate surface increases, in the also all ratio of the reflection increases of the interface of low refractive index dielectric (air of pore)/high refractive index medium (base material), cause optical attenuation according to its ratio, therefore, it also can't obtain sufficient reflectivity, but the air layer formation of the certain above size that in according to the present invention, produces in the reflection at the interface of nesa coating and air layer, because the decay of light is few, therefore as a result of, produce the reflecting effect that increases of reverberation components in proportions increase, obtain sufficient reflectivity.

And conductive reflecting film of the present invention can obtain the close resistivity of resistivity that itself is had with the metal that constitutes the contained metal nanoparticle of composition.That is, show and can be used as the low-resistivity of the main body same degree that the used for solar batteries electrode uses.

And, conductive reflecting film of the present invention with compare the long-time stability excellence of the reflectivity of film or adherence, resistivity by the film of sputter equal vacuum technology film forming.

In addition, get rid of vacuum vapour deposition or sputtering method equal vacuum technology as far as possible, according to using the wet type rubbing method can make conductive reflecting film, composite membrane at an easy rate.

Description of drawings

Fig. 1 is the figure in the cross section of the conductive reflecting film of schematically representing cladding plate type used for solar batteries of the present invention, composite membrane.

Symbol description

The 11-base material, 12-nesa coating, 13-photoelectric conversion layer, 14-nesa coating, 15-air layer, 16-conductive reflecting film, 17-composite membrane.

Embodiment

Then be used to implement mode of the present invention based on description of drawings.

Being used to form the conductive reflecting film composition of conductive reflecting film of the present invention, is to be dispersed in the composition for preparing in the decentralized medium according to metal nanoparticle.In the above-mentioned metal nanoparticle, the ratio of the silver in the metallic element is more than the 75 quality %, is preferably more than the 80 quality %.The ratio of the silver in the metallic element is made as scope more than the 75 quality %, and this is because cause during less than 75 quality % using the reflectivity of the conductive reflecting film that said composition forms to descend.And metal nanoparticle is that the protective agent of organic molecule main chain of carbon number 1～3 is by chemical modification by carbon skeleton.To be made as 1～3 scope to the carbon number of carbon skeleton that metal nanoparticle carries out protectant organic molecule main chain of chemical modification; this is because be difficult to break away from or decompose (separating or burning) if carbon number is heat when then protective agent is by sintering more than 4; residual a large amount of organic detritus in the above-mentioned conductive reflecting film, rotten or deterioration and the conductivity of conductive reflecting film and reflectivity are descended.

Metal nanoparticle is fit to contain with number average to be counted more than 70%, and being preferably 75% above primary particle diameter is the interior metal nanoparticle of 10～50nm scope.With respect to whole metal nanoparticles 100%, the content that with primary particle diameter is the metal nanoparticle in 10～50nm scope is made as in the scope more than 70% in number average, this is because following reason: if less than 70 quality %, then the specific area of metal nanoparticle increases and the shared ratio increase of organic substance, even the thermal capacitance during according to sintering easily breaks away from or decomposes the organic molecule of (separating or burning), the ratio shared owing to this organic molecule is many, therefore also residual a large amount of organic detritus in conductive reflecting film, rotten or the deterioration of this residue and the conductivity of conductive reflecting film and reflectivity are descended, or the particle size distribution of metal nanoparticle becomes wide and the density of conductive reflecting film becomes and descends easily, thereby the conductivity of conductive reflecting film and reflectivity are descended.In addition, the primary particle diameter of above-mentioned metal nanoparticle is made as in the scope of 10～50nm, this is because relevant with time stability (stable all the year round) according to the metal nanoparticle of statistical method primary particle diameter in 10～50nm scope.In addition, the assay method of the primary particle diameter of metal nanoparticle and number average is obtained by the following method in the present invention.At first, take the metal nanoparticle of gained with about about 500,000 times multiplying power by TEM (Transmission Electron Microscope, transmission electron microscope).Then, from the image of gained 200 metal nanoparticles being measured primary particle diameter, serves as that the basis makes particle size distribution with this measurement result.Then, obtaining primary particle diameter from the particle size distribution of making is metal nanoparticle shared number ratio whole metal nanoparticles in 10～50nm scope.

Preferably further comprise the additive more than a kind or 2 kinds that is selected from the group that constitutes by organic polymer, metal oxide, metal hydroxides, organo-metallic compound and silicone oil in composition at the conductive reflecting film that comprises this metal nanoparticle.According to the organic polymer, metal oxide, metal hydroxides, organo-metallic compound or the silicone oil that are contained in as additive in the composition, by combining with the chemical of base material or the anchoring effect increase, perhaps the wettability of metal nanoparticle in the sintering circuit and base material is improved, and can not damage conductivity thus and improves adherence with base material.

In addition, if use said composition to form conductive reflecting film, then can adjust the crystal grain-growth that causes by the sintering between metal nanoparticle.In the formation of the conductive reflecting film that uses said composition, needing no vacuum technology during owing to film forming, so the restriction of technology is little, and can significantly reduce the operating cost of manufacturing equipment.

The content of additive is preferably 0.2～10% for 0.1～20% of the silver nano-grain quality that constitutes metal nanoparticle.If the worry that the content of additive less than 0.1%, then has the density of the pore that occurs at the interface with nesa coating to uprise.If the content of additive surpasses 20%, then the conductivity of the conductive reflecting film that forms is brought harmful effect, produce specific insulation and surpass 2 * 10 ^-5The unfavorable condition of Ω cm.

As the organic polymer that uses with additive, use be selected from the group that copolymer and water-soluble cellulose by polyvinylpyrrolidone (Polyvinylpyrrolidone is hereinafter referred to as PVP), PVP constitute more than a kind or 2 kinds.Particularly, can enumerate PVP-methacrylate copolymer, PVP-styrol copolymer, PVP-vinyl acetate co-polymer etc. as the copolymer of PVP.In addition, can enumerate the cellulose ether of hydroxypropyl methylcellulose, methylcellulose, HEMC etc. as water-soluble cellulose.

As the metal oxide that uses with additive, be suitably for and comprise at least a kind oxide or the composite oxides that are selected from the group that constitutes by aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.Composite oxides are indium oxide-Sn system composite oxides (Indium Tin Oxide:ITO), antimony oxide-Sn system composite oxides (Antimony TinOxide:ATO), indium oxide-Zinc oxide composite oxides (Indium Zinc Oxide:IZO) etc. specifically.

As the metal hydroxides that uses with additive, be suitably for and comprise at least a kind the hydroxide that is selected from the group that constitutes by aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.

As the organo-metallic compound that uses with additive, be suitably for and comprise at least a kind metallic soap, metal complex or the metal alkoxide that is selected from the group that constitutes by silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin.For example metallic soap can be enumerated chromic acetate, formic acid manganese, ironic citrate, cobaltous formate, nickel acetate, silver citrate, Schweinfurt green, copper citrate, tin acetate, zinc acetate, zinc oxalate, acetic acid molybdenum etc.In addition, metal complex can be enumerated acetylacetone,2,4-pentanedione zinc complex, acetylacetone,2,4-pentanedione chromium complex, acetylacetone,2,4-pentanedione nickel complex etc.In addition, metal alkoxide can be enumerated titanium isopropoxide, methyl silicate, NCO propyl trimethoxy silicane, TSL 8330 etc.

As the silicone oil that uses with additive can use pure silicon oil and modified silicon oil both.Modified silicon oil further can use to the part of the side chain of polysiloxanes and import organic group and the silicone oil (branched chain type) that obtains, import organic group and the silicone oil (single tip type) that obtains and to a part and two terminal silicone oil that import organic groups and obtain (the two tip type of side chain) of the side chain of polysiloxanes to two terminal silicone oil (two tip type) that import organic groups and obtain of polysiloxanes, in two ends of polysiloxanes either party.Responding property of modified silicon oil silicone oil and non-reactive silicone oil, its two kinds all can be used as additive of the present invention and use.In addition, that reactive silicone oil is represented is amino modified, epoxide modified, carboxy-modified, methyl alcohol modification, sulfhydryl modified and xenogenesis functional group modification (epoxy radicals, amino, polyether-based), that non-reactive silicone oil is represented is polyether-modified, the modification of methyl styrene base, alkyl-modified, higher fatty acids is ester modified, fluorine modification and hydrophilic special modification.

On the other hand; constitute conductive reflecting film with in the metal nanoparticle of composition, the metal nanoparticle except that silver nano-grain preferably further contains a kind of particle that is selected from the group that is made of gold, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, iron, chromium and manganese or the metal nanoparticle that the mixing more than 2 kinds is formed or alloy composition constitutes.Metal nanoparticle beyond this silver nano-grain preferably is made as more than the 0.02 quality % with respect to whole metal nanoparticle 100 quality % and less than 25 quality %, further preferably is made as 0.03 quality %～20 quality %.The content of the particle beyond the silver nano-grain is made as more than the 0.02 quality % with respect to the whole metal nanoparticles of 100 quality % and less than the scope of 25 quality %, this is because as follows: if be lower than 0.02 quality %, though then there is not king-sized problem, but more than 0.02 quality % and be lower than in the scope of 25 quality %, compare the characteristic that can not worsen have the conductivity of the conductive reflecting film after the atmospheric exposure test (keep 1000 hours test) and reflectivity and atmospheric exposure test in the constant temperature and humidity cabinet of 100 ℃ of temperature and humidity 50% before, and be more than the 25 quality %, then just the conductivity and the reflectivity of the conductive reflecting film behind the sintering descend, and the conductivity and the reflectivity of the conductive reflecting film of the conductive reflecting film after the atmospheric exposure test before than atmospheric exposure test descend.

And, conductive reflecting film preferably contains 2.5～95.0 quality % with the composition that the content of the metal nanoparticle that comprises silver nano-grain in the composition is made of metal nanoparticle and decentralized medium with respect to 100 quality %, further preferably contains 3.5～90 quality %.The content that will comprise the metal nanoparticle of silver nano-grain is made as 2.5～95.0 quality % scopes with respect to the composition 100 quality % that are made of metal nanoparticle and decentralized medium, this is because as follows: if less than 2.5 quality %, though then to the not special influence of the characteristic of the conductive reflecting film behind the sintering, but be difficult to obtain the conductive reflecting film of desired thickness, if and surpass 95.0 quality %, then when the wet type coating of composition, lose as printing ink or the needed flowability of paste.

And, constituting conductive reflecting film uses the decentralized medium of composition with respect to the whole decentralized media of 100 quality %, be fit to contain water that 1 quality % is above, preferred 2 quality % are above and solvent, for example alcohols molten that 2 quality % are above, preferred 3 quality % are above with water.For example, when decentralized medium only is made of water and alcohols, then contain the alcohols of 98 quality % when containing 2 quality % water, contain the water that 2 quality % alcohol time-like then contains 98 quality %.And, decentralized medium, promptly the protection molecule that chemical modification is carried out on the metal nanoparticle surface contains hydroxyl (OH) or carbonyl (any one party C=O) or both sides.Be fit to the content of water is made as scope more than the 1 quality % with respect to the whole decentralized media of 100 quality %, this is because as follows: if less than 1 quality %, then be difficult to the film that sintering at low temperatures obtains by wet type rubbing method coating composition, and the conductivity of the conductive reflecting film behind the sintering and reflectivity descend, be fit to and be made as the above scope of 2 quality % with the content of the molten solvent of water with respect to the whole decentralized media of 100 quality %, this is because as follows: if less than 2 quality %, then same as described above, be difficult to the film that sintering at low temperatures obtains by wet type rubbing method coating composition, and the conductivity of the conductive reflecting film behind the sintering and reflectivity descend.In addition; if in the protective agent that metal nanoparticles such as silver nano-grain is carried out chemical modification, contain hydroxyl (OH); the dispersion stabilization excellence of composition then; also has effective function for the low-temperature sintering of filming; if in the protective agent that metal nanoparticles such as silver nano-grain is carried out chemical modification, contain carbonyl (C=O); then same as described above, the dispersion stabilization excellence of composition also has effective function to the low-temperature sintering of filming.As the solvent preferred alcohols molten that uses in the decentralized medium with water, wherein, as above-mentioned alcohols especially preferably use be selected from the group that constitutes by methyl alcohol, ethanol, propyl alcohol, butanols, ethylene glycol, propylene glycol, diethylene glycol (DEG), glycerine, isobornyl hexanol and erythrite more than a kind or 2 kinds.

The method for compositions that comprises metal nanoparticle that manufacturing is used to form conductive reflecting film of the present invention is as follows.

(a) will the carbon number of carbon skeleton that silver nano-grain carries out protectant organic molecule main chain of chemical modification be made as 3 o'clock,

At first, silver nitrate is dissolved in the water of deionized water etc. and prepares aqueous metal salt.On the other hand, natrium citricum is dissolved in the water such as deionized water, and in the concentration that obtains is 10～40% sodium citrate aqueous solution, in inert gas flows such as nitrogen, directly add graininess or pulverous ferrous sulfate and make its dissolving, preparation contained the reducing agent aqueous solution of citrate ions and ferrous ion with 3: 2 mol ratio.Then, the limit is stirred above-mentioned reducing agent aqueous solution limit and drip above-mentioned aqueous metal salt and mixing in this reducing agent aqueous solution in above-mentioned inert gas flow.Wherein, the addition of aqueous metal salt is preferably regulated the concentration of each solution, makes it become below 1/10 of the water-soluble liquid measure of reducing agent, also can make reaction temperature remain on 30～60 ℃ even drip the aqueous metal salt of room temperature thus.And the equivalent that the mixing ratio of above-mentioned two kinds of aqueous solution is adjusted to the ferrous ion that adds as reducing agent becomes 3 times of metal ion equivalent.That is, be adjusted to (molal quantity of the metal ion in the aqueous metal salt) * (valence mumber of metal ion)=3 * (molal quantity of ferrous ion in the reducing agent aqueous solution).After aqueous metal salt dripped and finishes, further the stirring of lasting mixed liquor was 10～300 minutes, thus the dispersion liquid that preparation is made of metallic colloid.At room temperature place this dispersion liquid, after the aggregation of the metal nanoparticle of precipitation separated by decantation or centrifugal separation etc., the water that adds deionized water etc. in this separator is as dispersion, carry out desalting processing by ultrafiltration, further, continuation is cleaned with the alcohols displacement, and the content that makes metal (silver) is 2.5～50 quality %.Use whizzer then, regulate the centrifugal force of this whizzer, separate coarse granule, silver nano-grain is prepared into that to contain 70% above primary particle diameter in number average be silver nano-grain in 10～50nm scope thus, promptly, being adjusted to respect to 100% whole silver nano-grains, is that the shared ratio of silver nano-grain in 10～50nm scope becomes more than 70% in the number average primary particle diameter.Can obtain thus the carbon number of carbon skeleton that silver nano-grain carries out protectant organic molecule main chain of chemical modification is 3 dispersion.

Then, the dispersions obtained final tenor (silver content) that is adjusted to respect to 100 quality % dispersions is become in the scope of 2.5～95 quality %.And, decentralized medium is made as when containing alcohol solution, preferably with the water in the solvent with alcohols is adjusted to more than 1% respectively and more than 2%.And, when further comprising additive in the composition, undertaken by in dispersion, add the additive more than a kind or 2 kinds that is selected from the group that constitutes by organic polymer, metal oxide, metal hydroxides, organo-metallic compound and silicone oil with required ratio.With respect to the composition of 100 quality % gained, the content of additive is adjusted in the scope of 0.1～20 quality %.The silver nano-grain that the protective agent that can obtain carbon number with carbon skeleton thus and be 3 organic molecule main chain carries out chemical modification is scattered in the composition that obtains in the decentralized medium.

(b) will the carbon number of carbon skeleton that silver nano-grain carries out protectant organic molecule main chain of chemical modification be made as 2 o'clock,

The natrium citricum that uses during with the preparation reducing agent aqueous solution replaces with natrium malicum, in addition carries out in the same manner with above-mentioned (a) and prepares dispersion.Can obtain thus the carbon number of carbon skeleton that silver nano-grain carries out the organic molecule main chain of chemical modification is 2 dispersion.

(c) will the carbon number of carbon skeleton that silver nano-grain carries out protectant organic molecule main chain of chemical modification be made as 1 o'clock,

The natrium citricum that uses during with the preparation reducing agent aqueous solution replaces with sodium glycollate, carries out in the same manner with above-mentioned (a) in addition and prepares dispersion.Can obtain thus the carbon number of carbon skeleton that silver nano-grain carries out the organic molecule main chain of chemical modification is 1 dispersion.

(d) carbon number of carbon skeleton that will carry out protectant organic molecule main chain of chemical modification to the metal nanoparticle beyond the silver nano-grain was made as 3 o'clock,

As the metal that constitutes silver nano-grain metal nanoparticle in addition, can enumerate gold, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, iron, chromium and manganese.The silver nitrate that preparation is used during aqueous metal salt replaces with gold chloride, chloroplatinic acid, palladium nitrate, ruthenium trichloride, nickel chloride, cuprous nitrate, stannous chloride, indium nitrate, zinc chloride, ferric sulfate, chromium sulfate or manganese sulfate, in addition carries out in the same manner with above-mentioned (a) and prepares dispersion.Can obtain thus the carbon number of carbon skeleton that the metal nanoparticle beyond the silver nano-grain carries out protectant organic molecule main chain of chemical modification is 3 dispersion.

In addition; the carbon number of carbon skeleton that will carry out protectant organic molecule main chain of chemical modification to the metal nanoparticle beyond the silver nano-grain is made as 1 or at 2 o'clock; the silver nitrate that preparation is used during aqueous metal salt replaces with the slaine of mentioned kind, carries out in the same manner with above-mentioned (b) or above-mentioned (c) in addition and prepares dispersion.Can obtain thus the carbon number of carbon skeleton that the metal nanoparticle beyond the silver nano-grain carries out protectant organic molecule main chain of chemical modification is 1 or 2 dispersion.

When together containing metal nanoparticle beyond the silver nano-grain as metal nanoparticle and silver nano-grain, for example if the dispersion that will comprise the silver nano-grain of making by the method for above-mentioned (a) as the 1st dispersion, the dispersion that will comprise the metal nanoparticle beyond the silver nano-grain of being made by the method for above-mentioned (d) is as the 2nd dispersion, then becomes 100 quality % with the 1st dispersion more than the 75 quality % with less than the total content that the 2nd dispersion of 25 quality % is mixed into the 1st and the 2nd dispersion.In addition, the 1st dispersion is not limited to comprise the dispersion of the silver nano-grain of being made by the method for above-mentioned (a), also can use to comprise by the dispersion of the silver nano-grain of the method manufacturing of above-mentioned (b) or comprise the dispersion of the silver nano-grain of being made by the method for above-mentioned (c).

In the manufacture method of the present invention, as shown in Figure 1, at first on the photoelectric conversion layer 13 that is laminated to the cladding plate type solar cell on the base material 11 by nesa coating 12, further form nesa coating 14, and, by the wet type rubbing method above-mentioned conductive reflecting film is coated on the nesa coating 14 with composition, form the conductivity reflective coating film,, preferably become the thickness of 0.1～1.5 μ m so that the thickness behind the sintering becomes 0.05～2.0 μ m.

Above-mentioned base material 11 can use glass, comprise the pottery of transparent conductive material or any one of the light-transmitting substrate that is made of macromolecular material, perhaps can use the light transmission lamination body more than 2 kinds that is selected from the group that is made of glass, the pottery that comprises transparent conductive material, macromolecular material and silicon.And, can also use any a kind base material that comprises nesa coating at least or the base material of film forming nesa coating from the teeth outwards.Can enumerate indium oxide system, Sn system, Zinc oxide as nesa coating.Indium tin oxide), IZO (Indium Zic Oxide) can enumerate indium oxide, ITO (Indium Tin Oxide: as indium oxide system.Can enumerate nesa (tin oxide SnO as Sn system ₂), antimony doped tin oxide), fluorine doped tin oxide ATO (Antimony Tin Oxide:.Can enumerate zinc oxide, AZO (Al-Doped ZnO), gallium-doped zinc oxide as Zinc oxide.Base material be preferably solar cell device or the band transparency electrode solar cell device in any one.Can enumerate ITO, ATO, nesa, IZO, AZO or the like as transparency electrode.In addition, can on substrate surface, form thin dielectric film as lead zirconate titanate (PZT).Can enumerate the substrate that forms by polyimides or PET organic polymers such as (PETGs) as polymeric substrate.Above-mentioned dispersion is coated on the surface of transparency electrode of the solar cell device of the surface of opto-electronic conversion semiconductor layer of solar cell device or band transparency electrode.

On photoelectric conversion layer 13, form nesa coating 14.Nesa coating 14 is not particularly limited, and can pass through known method formation in the past such as sputtering method, vacuum vapour deposition, hot CVD method, wet type rubbing method.And, when forming this nesa coating 14, at first make the electrically conducting transparent film composition by the wet type rubbing method.This electrically conducting transparent film composition comprises the electroconductive oxide particulate, is the composition of this electroconductive oxide microparticulate in decentralized medium.Indium oxide-Sn system composite oxides), (Antimony Tin Oxide: stannic oxide powder antimony oxide-Sn system composite oxides) or contain is selected from the Zinc oxide powder etc. of metal more than a kind or 2 kinds in the group that is made of Al, Co, Fe, In, Sn, Ga and Ti to ATO be preferably ITO (Indium Tin Oxide: as being contained in electroconductive oxide particulate in the electrically conducting transparent film composition.Al-Doped ZnO), IZO (Indium Zinc Oxide: indium oxide-Zinc oxide composite oxides), TZO (Tin Zinc Oxide: stanniferous Zinc oxide composite oxides) wherein, especially preferred ITO, ATO, AZO (Aluminum ZincOxide:.And, be contained in containing of electroconductive oxide particulate shared in the solids content in the electrically conducting transparent film composition of the proportional scope that is preferably 50～90 quality %.The electroconductive oxide particulate contain proportional be made as in the above-mentioned scope be because if less than lower limit then conductivity descend and not preferred, if surpass higher limit then adherence descend and not preferred.Wherein, especially be preferably in 70～90 quality % scopes.And the average grain diameter of electroconductive oxide particulate is in order to remain on the stability in the decentralized medium, preferably in 10～100nm scope, wherein especially preferably in 20～60nm scope.

The electrically conducting transparent film composition is the composition that comprises any one party in the polymer type adhesive that hardens by heating or the non-polymeric adhesive or both sides.Can enumerate acrylic resin, Merlon, polyester, alkyd resins, polyurethane, acrylic acid urethane, polystyrene, polyacetals, polyamide, polyvinyl alcohol, polyvinyl acetate, cellulose and siloxane polymer etc. as polymer type adhesive.And the hydrolysis body that preferably in polymer type adhesive, comprises metallic soap, metal complex or the metal alkoxide of aluminium, silicon, titanium, zirconium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum or tin.Comprise collosol and gel in the hydrolysis body of this metal alkoxide.Can enumerate metallic soap, metal complex, metal alkoxide, halogenated silanes class, 2-alkoxyethanol, beta-diketon and alkyl acetate etc. as the non-polymeric adhesive.And the metal that is contained in metallic soap, metal complex or metal alkoxide is aluminium, silicon, titanium, zirconium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium or antimony.These polymer type adhesives, non-polymeric adhesive harden by heating, thereby can form the ground fog rate under the low temperature and the nesa coating 14 of specific insulation.The ratio that proportional conduct accounts for solids content in the electrically conducting transparent film composition that contains of these adhesives is preferably in 5～50 quality % scopes, especially is preferably in 10～30 quality % scopes.

Preferably clear conduction film composition adds couplant according to employed other compositions.This is for the associativity that improves electrically conductive microparticle and adhesive, and the nesa coating 14 that formed by this electrically conducting transparent film composition and the adherence of photoelectric conversion layer 13 or conductive reflecting film 16.Can enumerate silane coupling agent, aluminium couplant and titanium couplant etc. as couplant.

Can enumerate vinyltriethoxysilane, γ-glycidyl ether oxygen base propyl trimethoxy silicane, γ-methacryloxypropyl trimethoxy silane as silane coupling agent.And can enumerate the aluminium couplant that contains the acetate alkoxyl shown in the following formula (1) as the aluminium couplant.In addition, can enumerate the titanium couplant shown in titanium couplant shown in following formula (2)～(4) or the following formula (5) as the titanium couplant with dialkyl phosphate base with dialkyl pyrophosphoric acid ester group.

(C ₈H ₁₇O) ₄Ti[P(OC ₁₃H ₂₇) ₂OH] ---------(5)

When using above-mentioned electrically conducting transparent film composition to form nesa coating 14, at first the electrically conducting transparent film composition is coated on the photoelectric conversion layer 13 and film forming by the wet type rubbing method, so that the thickness behind the sintering becomes 0.03～0.5 μ m, preferably become in 0.05～0.3 mu m range.Wherein, the thickness of nesa coating 14 is limited to 0.03～0.5 mu m range, and this is owing to if then can not get increasing fully reflecting effect less than 0.03 μ m or above 0.5 μ m.Then, this layered product was kept 5～60 minutes with 120～400 ℃ temperature in atmosphere or in the inert gas atmospheres such as nitrogen or argon gas and carry out sintering, thereby form nesa coating 14.

Any one of the preferred especially spraying process of above-mentioned wet type rubbing method, distribution rubbing method, spin-coating method, knife coating, slot coated method, ink-jet application method, silk screen print method, hectographic printing method or die rubbing method, but be not limited to this, can utilize all methods.

Spraying process is by compressed air dispersion to be made vaporific being coated on the base material, or with dispersion itself pressurization and make the vaporific method that is coated on the base material, distributing rubbing method is for example to join dispersion in the syringe and push the piston of this syringe and from the fine nozzle ejection dispersion of syringe front end, coat the method on the base material.Spin-coating method is to be added drop-wise to dispersion on the base material of rotation and the dispersion that will drip is diffused into the method for base material periphery by its centrifugal force, and knife coating is that the base material that the front end with cutter separates specified gap is arranged to and can be moved and from this cutter side group material supply dispersion and make the base material method that moves horizontally of side downstream upstream towards horizontal direction.The slot coated method is dispersion is flowed out from narrow slit and to be coated on method on the base material, and the ink-jet application method is to be filled into dispersion in the Inkjet Cartridge of commercially available ink-jet printer and the method for ink jet printing to the base material.Silk screen print method is to use yarn to make dispersion transfer to method on the base material thereon as the icon indicia material and via the domain picture of making.The hectographic printing method is not that the dispersion that will be attached on the version is attached directly on the base material, but is transferred to the hydrophobic printing process that utilizes printing ink on the base material from sheet rubber again on earlier from the version primary transfer to sheet rubber.The die rubbing method is to distribute dispersion that supplies in the die and the method that is expressed to the surface that is coated with the base material that moves on the film by slit with manifold.The die rubbing method has gap coating mode or slip coating method, curtain coating mode.

Then on nesa coating 14, form conductive reflecting film 16.Particularly, the base material that will have a conductivity reflective coating film in atmosphere or in the inert gas atmospheres such as nitrogen or argon gas with 100～300 ℃/minute, preferred 150～250 ℃/minute speed heats up, with 130～400 ℃, preferred 150～200 ℃ temperature kept 10～60 minutes, preferred 15～40 minutes and carry out sintering.With regard to this sintering, by heating up, thereby make a part of particle emersion in the conductive reflecting film, thereby can form conductive reflecting film 16, so that have air layer 15 with the part at the interface of nesa coating 14 with the speed in the above-mentioned scope.Constitute composite membrane 17 by formed conductive reflecting film 16 with nesa coating 14.In addition, the emersion of programming rate particle in the conductivity reflective coating film during less than 100 ℃/minute is less, generation is difficult to form the necessarily unfavorable condition of the air layer of above size, then the emersion of the particle in the conductivity reflective coating film is too much if surpass 300 ℃/minute, produces the unfavorable condition of nesa coating and the adherence decline of conductive reflecting film.

This air layer 15 is that pore below the 100nm is different with occur average diameter in a large number on the interface in the coating process in the past, on the nesa coating and the interface between the air layer according to air layer formation big or small more than certain, owing to the decay of the light that causes because of reflection is less, its result, produce the reflecting effect that increases of reverberation components in proportions increase, so compare with reflectance coating in the past, reflectivity increases.

The height of air layer 15 is 5～200nm, the scope of preferred 30～100nm, and the width of air layer 15 is 10～300nm, preferred 100～200nm scope.Be meant from calculating mean value at the width of this so-called air layer 15 with the area estimation longest diameter of the air layer 15 at the interface of nesa coating 14 and the shortest diameter and from this measured value.

And, for the gross area of the air layer 15 of reflectance coating area 5～70%, preferably in 30～50% scopes.

At this, the height gage of air layer 15 is fixed on 5～200nm scope, this is owing to produce the unfavorable condition that the increase effect of reflectivity descends during less than 5nm, if surpass the adhesive reduction that 200nm then produces nesa coating and conductive reflecting film.

And the width of air layer 15 is defined in 10～300nm scope, and this is owing to produce the unfavorable condition that the increase effect of reflectivity descends during less than 10nm, if surpass the adhesive reduction that 300nm then produces nesa coating and conductive reflecting film.

And, to be defined in 5～70% scopes with respect to the gross area of the air layer 15 of reflectance coating area, this is because less than 5% o'clock, reflection ratio on the interface of nesa coating 14 and air layer 15 is crossed low and the reverberation components in proportions does not increase, and very few and conductive reflecting film 16 becomes and peels off easily with the contact area of conductive reflecting film 16 if surpass 70% nesa coating 14.

In addition, the Determination of thickness method of the width of the height of the gross area with respect to the reflectance coating area of air layer, air layer, air layer and reflectance coating is obtained according to following method among the present invention.At first, for the conductive reflecting film that is adhered to the nesa coating on the base material, the cross section is exposed with the method processing of convergence ion beam (FIB).Then, by observing this cross section, observe the shape of metal film/substrate interface by scanning electron microscope (SEM).And, about this interface picture, obtain the thickness of reflectance coating, the average height of air layer, the mean breadth of air layer, estimate the gross area with respect to the reflectance coating area of air layer in addition.At this, the peristome diameter of being estimated is by regarding the peristome length in the sectional view as mean breadth evaluation.

At this, the thickness that will be made as according to the coating of wet type rubbing method behind the sintering becomes 0.05～2.0 mu m range, this be since during less than 0.05 μ m the sheet resistance value of the required electrode of solar cell insufficient, then do not have on the characteristic badly if surpass 2.0 μ m, but the use amount of material is more than required and cause the waste of material.

And; the sintering temperature that will have the base material of conductive reflecting film is made as 130～400 ℃ scope; this is because inadequate while of sintering between the metal nanoparticle during less than 130 ℃; heat during owing to the protective agent sintering is difficult to break away from or decomposes (separating or burning); so residual morely organic detritus in the conductive reflecting film behind the sintering; rotten or the deterioration of this residue and cause the conductivity of conductive reflecting film and reflectivity to reduce; if surpass 400 ℃ of advantages that then can't produce in this production of low temperature process; be that manufacturing cost increases the productivity reduction, especially to amorphous silicon; microcrystal silicon or use the optical wavelength zone of the opto-electronic conversion in these the mixed type silicon solar cell to exert an influence.

In addition; the sintering time that will have the base material of conductive reflecting film is made as 10～60 minutes scopes; this is because inadequate while of sintering between the metal nanoparticle during less than 10 minutes; because the heat during the protective agent sintering is difficult to break away from or decomposes (separating or burning); so residual morely organic detritus in the conductive reflecting film behind the sintering; rotten or the deterioration of this residue and cause the conductivity of conductive reflecting film and reflectivity to reduce; if the then not influence on the characteristic that surpasses 60 minutes, but that manufacturing cost increases to is required above and cause productivity to reduce.

In the additive, about copolymer, water-soluble cellulose, knownly in atmosphere, under about 200～300 ℃, begin thermal decomposition lentamente, but its decomposition rate is extremely slow as organic macromolecule PVP, PVP.But then decompose rapidly if surpass 400 ℃.For example in the time of 10 minutes, what the sintering of these organic molecules was preceding remaining in the film more than 90% the metal nanoparticle film at 130 ℃ of following sintering.On the other hand with the metal nanoparticle film at 400 ℃ of following sintering in the time of 10 minutes, the remaining in the film more than 50% of these organic molecules.

Like this, manufacture method of the present invention is by the wet type rubbing method above-mentioned conductive reflecting film to be coated on the nesa coating 14 with composition, can form conductive reflecting film 16 by the simple procedures that sintering have a base material of this conductive reflecting film so that with the interface of nesa coating 14 on have air layer 15.Because needing no vacuum technology during film forming,, and can significantly reduce the operating cost of manufacturing equipment so the restriction of technology is little.

Conductive reflecting film 16 of the present invention can obtain the close resistivity of resistivity that itself had with the metal that constitutes metal nanoparticle contained in the composition.That is, show and can be used as the low-resistivity of the main body same degree that the used for solar batteries electrode uses.

And, conductive reflecting film 16 of the present invention with compare the long-time stability excellence of the reflectivity of film or adherence, resistivity etc. by the film of sputter equal vacuum technology film forming.Its reason can be enumerated as follows: the conductive reflecting film of the present invention of film forming is compared with the film of film forming in a vacuum in atmosphere, is difficult to be subjected to the influence that causes because of the intrusion of moisture or oxidation etc.

The conductive reflecting film 16 of the invention described above is owing to the reflectivity height from the base material side, and the low-resistivity of demonstration and main body same degree, uses so can be used as the electrode of solar cell.

[embodiment]

Then together describe embodiments of the invention in detail with comparative example.

＜embodiment 1～37 〉

By classification 1～8 composition shown in the following table 1, contain proportional preparation electrically conducting transparent film composition.Classification sequence number in the table 1 of the electrically conducting transparent film composition that uses among each embodiment is shown in table 2～4.

In the classification 1, as shown in the following Table 1, IZO powder 15 quality % as the average grain diameter 0.025 μ m of electroconductive oxide powder, isopropyl alcohol 72.77 quality % as decentralized medium, non-polymeric adhesive 2-n-butoxy ethanol and 3-isopropyl-2 as adhesive, the mixed liquor 10 quality % of 4 pentanediones, as the indium nitrate of low resistance agent and the mixture of lead acetate (mass ratio 1: 1) 2.23 quality %, with described ratio and the total amount is made as 60g packs in the vial of 100cc, use the zirconium oxide bead (micro-hiker (ミ Network ロ Ha ィカ) of 100g diameter as 0.3mm, Showa Shell SekiyuK.K) disperseed 6 hours with paint shaker, obtain the electrically conducting transparent film composition thus.

In classification 2, as shown in the following Table 1, average grain diameter as the electroconductive oxide powder is the ito powder 7.5 quality % of 0.025 μ m, as decentralized medium, with isopropyl alcohol, ethanol and N, the mixed liquor of dinethylformamide (mass ratio 4: 2: 1) is made as this mixed solution 92.3 quality % of the 1st mixed liquor, as 2 of the non-polymeric type adhesive of adhesive, 4-pentanedione 0.038 quality %, as the titanium couplant 0.162 quality % shown in the above-mentioned formula (4) of couplant, with shown in ratio according to and classification 1 same method, obtain the electrically conducting transparent film composition.

In the classification 3, as shown in the following Table 1, as the average grain diameter of electroconductive oxide powder be the ATO powder 5 quality % of 0.025 μ m, as above-mentioned the 1st mixed liquor 50.99 quality % of decentralized medium, as the 2-positive propoxy ethanol 44 quality % of the non-polymeric adhesive of adhesive, as the titanium couplant 0.01 quality % shown in above-mentioned (4) of couplant, with shown in ratio according to and classification 1 identical method, obtain the electrically conducting transparent film composition.

In the classification 4, as shown in the following Table 1, AZO powder 5 quality % as the average grain diameter 0.025 μ m of electroconductive oxide powder, as above-mentioned the 1st mixed liquor 74.64 quality % of decentralized medium, as 2 of adhesive, 2-dimethyl-3, the mixed liquor of 5-acetyl butyryl and isopropyl acetate (mass ratio 1: 1) 20 quality %, as the titanium couplant 0.36 quality % shown in the above-mentioned formula (3) of couplant, with shown in ratio according to and classification 1 same method, obtain the electrically conducting transparent film composition.

In the classification 5, as shown in the following Table 1, TZO powder 5 quality % as the average grain diameter 0.025 μ m of electroconductive oxide powder, above-mentioned the 1st mixed liquor 93.95 quality % as decentralized medium, mixed liquor (mass ratio 4: 1: 1) 0.8 quality % as 2-isobutoxy ethanol and 2-(the just own oxygen base) ethanol and the n-pro-pyl acetate of adhesive, as the titanium couplant 0.25 quality % shown in the above-mentioned formula (5) of couplant, with shown in ratio according to and classification 1 same method, obtain the electrically conducting transparent film composition.

In the classification 6, at first, the ATO powder suspension of average grain diameter 0.010 μ m in water and pH is prepared as 7, was handled 30 minutes with ball mill.As water-soluble cellulose derivative hydroxypropyl cellulose being become 0.01% amount by quality ratio with respect to the ATO powder adds suspension to and obtains the conductive liquid acid solution.Like this conductive liquid acid solution that obtains is prepared into the concentration of solids content concn 18.5%, this dispersion liquid 100g is mixed under 40 ℃ with the aqueous gelatin solution 100g of 13.2 quality %, obtain the electrically conducting transparent film composition of water system.

In the classification 7, as shown in the following Table 1, ATO powder as the average grain diameter 0.025 μ m of electroconductive oxide powder is 5.3 quality %, as decentralized medium, with the mixed liquor (mass ratio is 98: 2) of ethanol and butanols this mixed liquor 85 quality %, as the SiO of adhesive as the 2nd mixed liquor ₂Bond 1.7 quality %, the titanium couplant 8.0 quality % as shown in the above-mentioned formula (3) of couplant with described mixed, obtain the electrically conducting transparent film composition.In addition, the SiO that uses as adhesive ₂Bond uses 4 mouthfuls of flasks of glass of 500ml, the tetraethoxysilane of adding 140g, the ethanol of 240g, and the 12N-HC of dissolving 11.0g and once adding in the pure water of 25g while stirring made by reacting down at 80 ℃ afterwards in 6 hours.

In the classification 8, as shown in the following Table 1, as the ito powder 8.0 quality % of the average grain diameter 0.025 μ m of electroconductive oxide powder, as above-mentioned the 2nd mixed liquor 88 quality % of decentralized medium, as the SiO of adhesive ₂Bond 2.0 quality % as the titanium couplant 2.0 quality % shown in the above-mentioned formula (2) of couplant, thereby obtain the electrically conducting transparent film composition with described mixed.In addition, the SiO that uses as adhesive ₂Bond by with classification 7 identical method manufacturings.

[table 1]

Then, by following order, preparation conductive reflecting film composition.

At first, silver nitrate is dissolved in the deionized water preparation aqueous metal salt.In addition, natrium citricum is dissolved in the deionized water, preparation concentration is the sodium citrate aqueous solution of 26 quality %.In remaining 35 ℃ stream of nitrogen gas, in this sodium citrate aqueous solution, directly add granular ferrous sulfate and make its dissolving, be prepared into the reducing agent aqueous solution that contains citrate ions and ferrous ion with 3: 2 mol ratio.

Then, above-mentioned stream of nitrogen gas is being remained under 35 ℃ the state, the stirrer of magnetic stirrer is joined in the reducing agent aqueous solution, make stirrer with the rotation of the rotating speed of 100rpm, the limit is stirred above-mentioned reducing agent aqueous solution limit and is dripped above-mentioned aqueous metal salt and mix in this reducing agent aqueous solution.Wherein, the addition of the aqueous metal salt that adds in the reducing agent aqueous solution is by regulating the concentration of each solution, make below 1/10 of its amount that becomes the reducing agent aqueous solution, thereby also still can remain 40 ℃ even drip the aqueous metal salt reaction temperature of room temperature.And the mixing ratio of the above-mentioned reducing agent aqueous solution and aqueous metal salt is set at: the citrate ions of the reducing agent aqueous solution and the mol ratio of ferrous ion are 3 times with respect to the total atom valence mumber of the metal ion in the aqueous metal salt.After in the reducing agent aqueous solution, dripping the aqueous metal salt end, further mixed liquor is continued to stir 15 minutes, thus, make the inner metallic particles that produces of mixed liquor, acquisition is dispersed with the metallic particles dispersion liquid of metallic particles.The pH of metallic particles dispersion liquid is 5.5, and the chemical stoichiometric growing amount of metallic particles is 5g/L in the dispersion liquid.

By at room temperature placing the dispersion liquid obtain, and make the metallic particles precipitation in the dispersion liquid, separate the aggregation of settled metallic particles by decantation.Add deionized water in the accumulation of metal thing that separates, make dispersion, carry out desalting processing by ultrafiltration, replace cleaning with methyl alcohol in addition then, the content with metal (silver) is made as 50 quality % thus.Use centrifugal separator to regulate the centrifugal force of this centrifugal separator then, particle separation diameter surpasses the bigger silver-colored particle of 100nm, and being adjusted to thus and making primary particle diameter is that the interior silver nano-grain of 10～50nm scope contains 71% in number average.That is, being adjusted in number average is that the shared ratio of silver nano-grain in 10～50nm scope is 71% with respect to the primary particle diameter of 100% whole silver nano-grains.The silver nano-grain that obtains is that the protective agent of 3 organic molecule main chain carries out chemical modification by the carbon number of carbon skeleton.

Then, the metal nanoparticle that 10 mass parts are obtained adds in the mixed solution that 90 mass parts contain water, ethanol and methyl alcohol and mixes, thereby make its dispersion, and, in this dispersion liquid, add the additive shown in table 2～table 4, so that become the ratio shown in following table 2～table 4, can obtain the conductive reflecting film composition respectively thus.In addition, the formation conductive reflecting film contains the above silver nano-grain of 75 quality % with the metal nanoparticle of composition.

In addition, when containing silver nano-grain metal nanoparticle in addition as metal nanoparticle with silver nano-grain, the dispersion liquid of the silver nano-grain that will be obtained by said method is as the 1st dispersion liquid, in addition, use the slaine of the kind that forms the metal nanoparticle in addition of the silver nano-grain shown in following table 2～table 4 to replace silver nitrate, in addition the manufacture method with above-mentioned silver nano-grain is identical, the dispersion liquid of the metal nanoparticle beyond the preparation silver nano-grain, with the dispersion liquid of this metal nanoparticle as the 2nd dispersion liquid, before adding additive, mix the 1st dispersion liquid and the 2nd dispersion liquid so that become the ratio shown in following table 2～table 4, obtain the conductive reflecting film composition thus.

The electrically conducting transparent film composition that obtains is coated on the base material shown in following table 2～table 4 by various film build methods, made the thickness behind the sintering become 0.7～1.3 * 10 ²Nm, forming transparent conductivity 25 ℃ of following dryings of temperature 5 minutes then films, then the conductive reflecting film that will obtain is coated on formed electrically conducting transparent films by various film build methods with composition, make the thickness behind the sintering become 0.05～2.0 μ m, then 25 ℃ of temperature dry 5 minutes and form the conductivity reflective coating film down.Then carry out sintering, on base material, form the composite membrane that constitutes by nesa coating and conductive reflecting film thus according to the heat-treat condition shown in following table 2～table 4.

In addition, in table 2～table 4, PVP represents that Mw is 360,000 polyvinylpyrrolidone, and pet sheet shows PETG.

＜comparative example 1～3 〉

Form nesa coating according to sputtering method, so that thickness becomes 0.5～2 * 10 as vacuum vapour deposition ²After the nm, on this nesa coating, use the conductive reflecting film composition identical with embodiment 1, form the conductivity reflective coating film by the method identical with embodiment 1, carry out sintering according to the heat-treat condition shown in the following table 4, on base material, form the composite membrane that constitutes by nesa coating and conductive reflecting film thus.

[table 2]

[table 3]

[table 4]

＜comparative test 1 〉

About the composite membrane that constitutes by nesa coating and conductive reflecting film that on the base material that obtains by embodiment 1～37 and comparative example 1～3, forms, to the interface of nesa coating on the backside reflection rate of distribution, air layer and conductive reflecting film of the pore that occurs estimate.Evaluation result is shown in respectively at following table 5 and table 6.

The assay method of the average height of air layer, mean breadth and area ratio/occupancy ratio is for the conductive reflecting film that adheres to the nesa coating on the base material, process by convergence ion beam (FIB) method the test portion cross section is exposed, observe the cross section of this test portion, the interface shape of observing metal film/base material thus by scanning electron microscope (SEM).And, about this interface picture, obtain average height, the mean breadth of peristome, further estimate area ratio/occupancy ratio.At this, the diameter of the peristome of being estimated is by regarding the peristome length in the sectional view as mean breadth evaluation.

And the evaluation of the backside reflection rate of conductive reflecting film is measured the diffuse reflectance of the conductive reflecting film under wavelength 500nm and the 1100nm by with ultra-violet and visible spectrophotometer and integrating sphere combination.

[table 5]

[table 6]

As can be known from table 5 and table 6, confirmed following result: in sintering with in the comparative example 1～3 that heats up less than 100 ℃/minute speed, more than the reflectivity height to 85% of 1100nm, but the reflectivity of 500nm is low to moderate less than 80%, because the wavelength reflectivity produces deviation.

On the other hand, in sintering, among the embodiment 1～37 with 100～300 ℃/minute speed intensifications, the reflectivity of both sides' wavelength of 500nm and 1100nm all obtains high to the reflectivity more than 80%.

Industrial applicibility

The present invention is as following technology and very suitable, that is, be suitable for take with transparent bases such as glass as sensitive surface as electrode feature, cladding plate type solar cell, that be used for being arranged at low cost fabrication the sensitive surface opposition side.

And the application of the invention can replace with coating, sintering process with nesa coating and the conductive reflecting film that is formed by the vacuum film formation method in the past, can expect the significantly reduction of manufacturing cost.

Claims

1. a conductive reflecting film is formed on the nesa coating of film forming on the photoelectric conversion layer of cladding plate type thin-film solar cells, it is characterized in that,

The composition that will comprise metal nanoparticle by the wet type rubbing method is coated on the described nesa coating, and sintering has described base material of filming, and forms reflectance coating thus so that the part at the interface of described reflectance coating and described nesa coating has air layer,

The air layer of described generation with respect to the gross area of reflectance coating area in 5～70% scopes.

2. conductive reflecting film as claimed in claim 1, wherein, the height of air layer is the scope of 5～200nm, the width of described air layer is the scope of 10～300nm.

3. conductive reflecting film as claimed in claim 1 or 2 wherein, comprises the material more than a kind or 2 kinds that is selected from the group that copolymer and water-soluble cellulose by polyvinylpyrrolidone, polyvinylpyrrolidone constitute in the reflectance coating.

4. conductive reflecting film as claimed in claim 1, wherein, in the reflectance coating in the contained metallic element ratio of silver be more than the 75 quality %.

5. conductive reflecting film as claimed in claim 1, wherein, the thickness of reflectance coating is in the scope of 0.05～2.0 μ m.

6. conductive reflecting film as claimed in claim 1, wherein, with regard to metal nanoparticle contained in the reflectance coating, particle diameter is counted more than 70% with number average at the particle of 10～50nm scope.

7. conductive reflecting film as claimed in claim 1, wherein, comprise of the coating of the composition of metal nanoparticle according to the wet type rubbing method, be to be coated with into thickness behind the sintering to become coating in 0.05～2.0 mu m range, the sintering with the base material of filming is to keep carrying out in 10～60 minutes under 100～300 ℃/minute, 130～400 ℃ temperature at programming rate.

8. conductive reflecting film as claimed in claim 1, wherein, the wet type rubbing method is any one of spraying process, distribution rubbing method, spin-coating method, knife coating, slot coated method, ink-jet application method, silk screen print method, hectographic printing method or die rubbing method.

9. conductive reflecting film as claimed in claim 1; wherein; the ratio of the composition that comprises metal nanoparticle by silver in the metallic element is that the metal nanoparticle more than the 75 quality % is dispersed in the decentralized medium and prepares; described metal nanoparticle by carbon skeleton be the protective agent of organic molecule main chain of carbon number 1～3 by chemical modification, it is the metal nanoparticle of 10～50nm scope that described metal nanoparticle contains the primary particle diameter of counting more than 70% with number average.

10. conductive reflecting film as claimed in claim 1, wherein, base material is any one of glass, the pottery that comprises transparent conductive material or the light-transmitting substrate that is made of macromolecular material, or is selected from the light transmission lamination body more than 2 kinds in the group that is made of described glass, the pottery that comprises transparent conductive material, macromolecular material and silicon.

11. conductive reflecting film as claimed in claim 1, wherein, the composition that contains metal nanoparticle further comprises the additive more than a kind or 2 kinds that is selected from the group that is made of organic polymer, metal oxide, metal hydroxides, organo-metallic compound and silicone oil.

12. conductive reflecting film as claimed in claim 11, wherein, organic polymer is the material more than a kind or 2 kinds that is selected from the group that copolymer and water-soluble cellulose by polyvinylpyrrolidone, polyvinylpyrrolidone constitute.

13. conductive reflecting film as claimed in claim 11, wherein, metal oxide is to comprise at least a kind oxide or the composite oxides that are selected from the group that is made of aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.

14. conductive reflecting film as claimed in claim 11, wherein, metal hydroxides is to comprise at least a kind the hydroxide that is selected from the group that is made of aluminium, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony.

15. conductive reflecting film as claimed in claim 11, wherein, organo-metallic compound is to comprise at least a kind metallic soap, metal complex or the metal alkoxide that is selected from the group that is made of silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin.

16. conductive reflecting film as claimed in claim 9 wherein, contains water and the alcohols more than the 2 quality % more than the 1 quality % as decentralized medium.

17. the manufacture method of a conductive reflecting film, it is characterized in that, the composition that will comprise metal nanoparticle by the wet type rubbing method is coated on the nesa coating of film forming on the photoelectric conversion layer of cladding plate type thin-film solar cells, to have described base material of filming with 100～300 ℃ of/minute intensifications, under 130～400 ℃ temperature, kept 10～60 minutes and carry out sintering, form film thus so that the part at the interface of this film and described nesa coating has air layer, the gross area with respect to the reflectance coating area of the air layer of described generation is located in 5～70% scopes.

18. the manufacture method of conductive reflecting film as claimed in claim 17, wherein, the composition that comprises metal nanoparticle is that metal nanoparticle more than the 75 quality % is dispersed in the decentralized medium and prepares according to the ratio of silver in the metallic element,

Described metal nanoparticle by carbon skeleton be the protective agent of organic molecule main chain of carbon number 1～3 by chemical modification,

It is the metal nanoparticle of 10～50nm scope that described metal nanoparticle contains the primary particle diameter of counting more than 70% with number average,

On nesa coating, the coating of described composition is become in 0.05～2.0 mu m range for the thickness behind the sintering by the wet type rubbing method.

19. the composite membrane of a cladding plate type used for solar batteries, it is characterized in that, on the photoelectric conversion layer of cladding plate type solar cell, form nesa coating, on described nesa coating, form each described conductive reflecting film in the claim 1 to 18, or pass through the conductive reflecting film of the manufacture method manufacturing of conductive reflecting film.

20. a layered product uses each described conductive reflecting film in the claim 1 to 19, or passes through the conductive reflecting film of the manufacture method manufacturing of conductive reflecting film.

21. a solar cell, each the described conductive reflecting film in the usefulness claim 1 to 20, layered product or the conductive reflecting film of making by the manufacture method of conductive reflecting film, layered product are as electrode.

22. a solar cell, each the described conductive reflecting film in the usefulness claim 1 to 21 is as electrode.