TW201234628A - Sensitizing agent of solar cells and the solar cells using the same - Google Patents

Abstract

The topic of the present invention is to provide a sensitizing agent for solar cell which can suppress diffusion of metal to a power generating layer and expect the realization of high power generation efficiency of near field light produced by the resonance of surface plasmon of free nano metal particles. The problem solving means is a sensitizing agent of solar cell that is characterized by forming nano metal particles with transparent layer having surface plasmon effect and the sensitizing layer of solar cells contain the sensitizing agent of solar cell. The sensitizing layer of the solar cell can be formed by the method of wet type coating.

Description

201234628 VI. Description of the Invention: [Technical Field] The present invention relates to a sensitizer for a solar cell, which is formed by forming a film in the interior of a power generation layer of a solar cell or an interface of a power generation layer, by means of a metal nanoparticle. Surface plasmon effect can be expected to achieve high conversion efficiency. [Prior Art] Now, in terms of environmental protection, research and development of Clean Energy is underway. Among them, solar cells are attracting attention because of the unlimited sunlight and pollution. In the past, for solar power generation by solar cells, most of them used single crystal or polycrystalline sand. On the other hand, a semiconductor such as amorphous germanium, that is, a so-called thin film semiconductor solar cell (hereinafter referred to as a thin film solar cell) is used, and a semiconductor layer of a desired photoelectric conversion layer is formed on an inexpensive substrate such as glass or stainless steel. Just fine. Therefore, this thin film solar cell is considered to be the mainstream of solar cells in the future because it is thin and lightweight, inexpensive to manufacture, and easy to increase in area. The power generation efficiency of these solar cells, that is, in order to improve the photoelectric conversion efficiency, it is important to introduce the incident light into the power generation layer without loss. In order to achieve such a revolutionary approach, attempts have been made to utilize the near field light of surface plasmons induced by metallic nanoparticles, which are tied to the n-type doped charge transport layer. Between each of the charge transport layers of the p-type doped charge transport layer, a photosensitive layer containing a nanoparticle that absorbs near-infrared rays or the like using a surface plasma-5-201234628 or a polaron mechanism is formed (Patent Document 1), or a type A solar cell comprising a bonded body of a P-type thin film semiconductor layer and an N-type thin film semiconductor layer, which is formed by metal nanoparticles which generate surface plasmon resonance (Patent Document 2) 〇 [Prior Art Document] [Patent Document 1] Japanese Laid-Open Patent Publication No. 2009-533025 [Patent Document 2] JP-A-2009-246025 SUMMARY OF INVENTION [Problems to be Solved by the Invention] However, an n-type doped charge transport layer is used. The photosensitive layer formed between the layers of the p-type doped charge transport layer, when the metal nanoparticles directly contact the power generation layer, the metal diffuses into each of the charge transport layers, and the long period of time cannot be obtained. Problems such as reliability. In a solar cell including a metal electrode formed by metal nanoparticles, since the thin film semiconductor layer is in contact with the metal electrode, the metal diffuses into the thin film semiconductor layer, and there is a problem that reliability in a long period of time cannot be obtained. . On the other hand, in order to form a film containing metal nanoparticles on the surface of the substrate without contacting the power generation layer with the metal nanoparticles, the proximity field generated from the surface plasmon resonance of the metal nanoparticles The distance between the light and the power generation layer is far, and sufficient enhancement cannot be obtained. -6- 201234628 The present invention provides a sensitizer for a solar cell, which is a method for suppressing diffusion of a metal to a power generation layer, and is expected to be close by surface plasmon resonance of metal nanoparticles. The realization of high power generation efficiency of field light (hereinafter referred to as "surface plasmon effect"). [Means for Solving the Problem] The present invention relates to a sensitizer for a solar cell, a composition for a sensitizing layer, a sensitizing layer, and a method for using the same according to the configuration described below. Solar battery. (1) A sensitizer for a solar cell characterized in that the surface is a metal nanoparticle which forms a transparent layer and which resonates on the surface plasmon. (2) The sensitizer for a solar cell according to the above (1), wherein the metal of the metal nanoparticles is gold, silver, copper or palladium, or at least selected from the group consisting of gold, silver, copper and palladium. Two kinds of mixed metals or alloys. (3) The sensitizer for a solar cell according to (1) or (2) above, wherein the metal nanoparticles have an average particle diameter of 5 to 300 nm. (4) The sensitizer for a solar cell according to any one of the above (1) to (3), wherein the transparent layer is SiO 2 , TiO 2 or Zr 02 , or is grouped from SiO 2 , Ti 〇 2 and Zr 〇 2 A mixture of at least two of the selected ones. (5) The sensitizer for a solar cell according to any one of the above (1) to (3) wherein the transparent layer is an acrylic resin, a polycarbonate, a polyester, an alkyd resin, or a polyurethane. , at least a group of 201234628 selected from the group consisting of acrylic urethane, polystyrene, polyacetal, polyamidamine, polyvinyl alcohol 'polyvinyl acetate, cellulose and decane polymer One. (6) The sensitizer for a solar cell according to any one of the above (1) to (5) wherein the transparent layer has a thickness of 1 to 20 nm. (7) A sensitizing layer for a solar cell, comprising the sensitizer for a solar cell according to any one of the above (1) to (6), and a dispersing medium. (8) A sensitizing layer for a solar cell, comprising the sensitizer for a solar cell according to any one of the above (1) to (6). (9) A solar cell comprising the sensitization layer for a solar cell according to (8) above. Moreover, the present invention relates to a method for producing a sensitized layer for a solar cell, and a method for producing a sensitized layer for a solar cell, which is characterized in that the sensitizing layer for a solar cell according to the above (7) is used. The material is applied to the power generation layer of the solar cell, the transparent conductive film or the electrode by a wet coating method. (11) The method for producing a sensitized layer for a solar cell according to the above (10), wherein the wet coating method is a spray coating method, a dispensing method, a spin coating method, a knife coating method, or a slit Any one of a coating method, an inkjet coating method, a screen printing method, a lithography method, or a die coating method. [Effect of the Invention] According to the invention (1), the surface plasmon effect of the metal nanoparticles is used to increase the power generation efficiency, and the transparent layer can provide a solar cell having long-term stability and good stability ** 8 - 201234628. Further, the solar cell sensitizer may be contained in the power generation layer, anywhere between the power generation layer and the electrode. According to the invention (7), it is possible to manufacture a sensitized layer for a solar cell which improves the photoelectric conversion efficiency of the solar cell and has good long-term stability. Further, according to the invention (9)', the power generation efficiency of the solar cell can be improved, and the long-term stability is good. Therefore, the solar cell of the invention (11) has high power generation efficiency and good long-term stability. According to the invention (12), it is possible to easily produce a sensitized layer for a solar cell which improves the power generation efficiency of the solar cell and has good long-term stability. [Best Mode for Carrying Out the Invention] Hereinafter, the present invention will be specifically described based on an embodiment.尙 If there is no special notice, in addition to the inherent number of cases, % is shown as mass %. A solar cell using the sensitizer for a solar cell of the present invention (hereinafter referred to as "sensitizer") will be described. Fig. 1 shows an example of a cross-sectional view of a germanium heterojunction solar cell using a sensitizer. 1 shows that a-Si (i type) 32 and a-Si (p type) 33 are formed on a single crystal Si (n type) 31 to form a power generation layer 30, and a transparent conductive film 60 is formed on the power generation layer 30. And the Ag wiring 70; on the other hand, the A1 layer 20 is formed on the back surface of the single crystal Si (n-type). The sensitizer 10 of the present invention is formed between the power generation layer 30 and the transparent conductive film 60, and enhances the sunlight by the plasmonic effect of the metal nanoparticles in the sensitizer 1 以 to enhance the solar cell 1 Power generation efficiency. Here, the metal nanoparticle which generates the surface plasmon resonance is considered to be a light-generating surface corresponding to the surface plasmon resonance frequency of the metal nanoparticle which has been incident into the sunlight of -9-201234628. The plasmonic resonance resonates significantly to enhance the electric field near the metal nanoparticle layer and increase the intensity of the near-field light, which can generate photocurrent in the power generation layer. Fig. 2 shows an example of a cross-sectional view of a super-straight type solar cell using a sensitizer. 2 is a transparent conductive film 61 formed on a glass substrate 71, a power generation layer 40 composed of a_Si (p type) 43 and a-Si (i type) 42 and a-Si (n type) 41, and a back electrode layer. 21. The sensitizer 11 of the present invention is formed between the transparent conductive film 61 and the power generation layer 40, and the surface plasmon effect of the metal nanoparticles in the sensitizer 11 can improve the power generation efficiency of the solar cell 2. Fig. 3 shows another example of a cross-sectional view of a super-straight type solar cell using a sensitizer. When viewed from the sunlight side, this example is an example in which a sensitizer is formed on the back surface of the power generating layer. 3 is a transparent conductive film 63 formed on a glass substrate 72, a power generation layer 50 composed of a-Si (p type) 53 and a-Si (i type) 52 and a-Si (n type) 51, and transparent conductive The film 62 and the back electrode layer 22, the sensitizer 12 of the present invention is formed between the power generation layer 50 and the transparent conductive film 62, and can be improved by the surface plasmon effect of the metal nanoparticles in the sensitizer 12. The power generation efficiency of the solar cell 3. In this way, when viewed from the sunlight side, whether the sensitizer is formed on the incident side of the power generation layer or on the back side, the surface plasmon effect can improve the power generation efficiency of the solar cell, and is also preferable. It is formed on the incident side and the back side of the power generation layer. [The sensitizer for solar cells] -10-.201234628 The sensitizer of the present invention is characterized in that the surface is a metal nanoparticle which is formed with a transparent layer and which generates surface plasmon resonance. The metal of the metal nanoparticle is, for example, one or a mixture of two or more selected from the group consisting of gold, silver, copper, palladium, platinum, rhodium, nickel, tin, indium, zinc, iron, chromium, and manganese. a metal or alloy, if it is gold, silver, copper or palladium, or a mixed metal or alloy of at least two selected from the group consisting of gold, silver, copper and palladium, since the surface plasmonic wavelength can be made visible. Therefore, it is appropriate. The average particle diameter of the metal nanoparticles is preferably 5 to 300 nm, and the surface plasmon effect can be selected to be a strong wavelength by the average particle diameter and the kind of the metal. Here, the average particle diameter is measured by the BET method measured by the specific surface area of QUANTACHROME AUTOSORB-1. Unless otherwise specified, the measurement was carried out by the BET method measured by the specific surface area of QUANTACHROME AUTOSORB-1. When the shape of the metal nanoparticles is spherical or needle-shaped, it is preferable from the viewpoint of dispersibility and conductivity. The transparent layer prevents the diffusion of metal nanoparticles to the power generation layer. Further, when the transparent layer has a refractive index in the middle of the power generation layer or the electrode in the visible light region, reflection of incident light at the interface between the power generation layer and the transparent layer can be suppressed, and the incident light can be efficiently converted to the near field. It is appropriate. The transparent layer of the inorganic material is preferably Si02, Ti02 or Zr02, or a mixture of at least two selected from the group consisting of SiO2, Ti02 and Zr02. Further, the transparent layer of the organic substance is preferably an acrylic resin, a polycarbonate, a polyester, an alkyd resin, a polyurethane, an acrylic urethane, a polystyrene or a polyacetal. At least one selected from the group consisting of polyamine, polyvinyl alcohol, polyvinyl acetate, -11 - 201234628 cellulose and a siloxane polymer. The thickness of the transparent layer is preferably from 1 to 20 nm. When it is less than 1 nm, the metal nanoparticles have a diffusion in the power generation layer; if it exceeds 20 nm, the transparent layer is excessive and has no effect. Here, the thickness of the transparent layer is measured by a transmission electron microscope. [Composition for sensitized layer for solar cell] The composition for sensitized layer for solar cell of the present invention (hereinafter referred to as "the composition for sensitized layer" In addition, the sensitizer for a solar cell and the dispersion-dispersing medium are used to disperse the sensitizer for a solar cell, and the film-forming property of the composition for a sensitizing layer for a solar cell is improved. As the dispersing medium, water or alcohol is preferred. More preferably, the alcohol is selected from the group consisting of methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, diethylene glycol, glycerin, isodecylhexanol, and erythritol. More than two. The composition for the sensitized layer for the solar battery is preferably from 50 to 99 parts by mass based on 100 parts by mass of the dispersion medium. The composition for the sensitized layer may be optionally blended with an antioxidant, a leveling agent, a thixotropic agent, a ruthenium, a stress relieving agent, other additives, etc., without departing from the scope of the object of the present invention. [The sensitizing layer for solar cells] The sensitizing layer for solar cells of the present invention (hereinafter referred to as "sensitizing layer") contains the above sensitizing agent. For example, as shown in FIG. 1, in the sensitized layer 1 00 -12 - 201234628, the transparent conductive film 60 can penetrate between the gaps between the sensitizers 1 。. [Method for Producing Sensitized Layer for Solar Cell] The method for producing a sensitized layer according to the present invention is characterized in that the composition for use is applied to a power generating electrode of a solar cell by a wet coating method. The sensitizer is an example of a manufacturing process in which a transparent layer is coated on the metal nanoparticles, and the following steps are as follows: Step 1: Preparation of a metal nanoparticle dispersion; Step 2: Adding and mixing a surface coating agent for forming a transparent layer In the nanoparticle dispersion; Step 3: Centrifuge the precipitate (sensitizer) to remove the solvent. Step 4: Add the solvent again, stir and make the nanoparticles. Step 5: Centrifuge the precipitate to remove the solvent; Step 6: Repeat steps 4 and 5 to wash. The sensitizing layer uses a composition system to mix the desired components by a conventional paint shaker, a ball mill, a sand mixer, a century triaxial machine, etc., and a translucent adhesive, depending on the situation, can be made electrically The particles are dispersed and produced. Of course, it is also possible to manufacture by normal operation. If the composition of the sensitizing layer is wet-coated on the solar cell, on the transparent conductive film, or on the electrode, it may be appropriately determined according to the solar energy structure, for example, as shown in FIG. On the layer of sensation or. As a gold-binding agent; a sub-dispersed paint shake mill, a transparent conductive power generation layer battery heterojunction-13-201234628, in combination with a solar cell, it is preferred to wet-coat the sensitized layer composition to have been formed beforehand There is a single Si (n type) 31 on a-Si (p type) 33. The wet coating method is preferably spray coating, dispensing, spin coating, knife coating, slit coating, inkjet coating, screen printing, lithography or Any of the die coating methods is not limited thereto, and all methods can be utilized. The sensitized layer can be obtained by drying the sensitized layer formed by wet coating with a composition coating film. The thickness of the sensitized layer is preferably 〇.〇1 to 〇.3μιη in order to suppress the self-absorption of light as much as possible. The sensitized layer of the present invention can be produced in such a manner. When the transparent conductive film is formed on the sensitized layer, if the composition for a transparent conductive film is applied by a wet coating method and then hardened or calcined, it is not necessary to use expensive equipment. It is convenient to manufacture at a low cost. At this time, when the transparent conductive film composition penetrates the sensitized layer, the adhesion strength between the sensitized layer and the power generation layer can be improved. The transparent conductive film composition may be used as long as it is used for a solar cell containing a light-transmitting adhesive. When the transparent conductive particles are contained, the conductivity of the transparent conductive film can be improved, and heat and light can be suppressed. It is preferable that the conductive reflective film is deteriorated. Examples of the light-transmitting adhesive include non-polymer type adhesives such as a polymer type binder such as an acrylic resin, a polycarbonate, or a polyester, or a metal soap, a metal complex, a metal alkoxide, or a hydrolyzate of a metal alkoxide. "Agent" as transparent conductive particles, for example, ITO (Indium Tin Oxide), antimony Tin Oxide (Antimony Tin Oxide), AZO (Aluminum Zinc Oxide: Ming Zhan Oxygen-14-201234628 Word), IZO (Indium Zinc Oxide), ΤΖΟ (Tin Zinc Oxide). When the thickness of the right transparent conductive film is 0.01 to 〇·5 μm, it is preferably from the viewpoint of adhesion, and more preferably 0.02 to Ο.ΐμπι. If the thickness of the transparent conductive film is less than 0.03 μm or more than 0.5 μm, the antireflection effect cannot be sufficiently obtained. [Embodiment] [Embodiment] Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited thereto. <<Preparation of Silver Nanoparticles&gt; Silver nitrate was dissolved in deionized water to prepare an aqueous metal salt solution. Further, sodium citrate was dissolved in deionized water to prepare a sodium citrate aqueous solution having a concentration of 26% by mass. The ferrous ferrous sulfate was directly added to dissolve in the aqueous solution of sodium citrate while maintaining a nitrogen gas flow at 35 ° C to prepare a reducing agent having a molar ratio of citrate ion to ferrous ion of 3:2. Aqueous solution. Next, the nitrogen gas stream was maintained at 35 t while the stirrer of the magnetic stirrer was introduced into the reducing agent aqueous solution, and stirred at a swing speed of the stirrer: 100 rpm, while the above aqueous metal salt solution was dropped into the reduced form. The aqueous solution is mixed and mixed. Here, the addition amount of the metal salt aqueous solution of the reducing agent aqueous solution is adjusted so that the concentration of each solution is equal to or less than 1/1 量 of the amount of the reducing agent aqueous solution, and even if it is dropped into the room temperature, the metal salt dissolves -15- The liquid of 201234628 also kept the reaction temperature set at 40 °C. Further, the mixing ratio of the reducing agent aqueous solution and the metal salt aqueous solution is set to 3 times the molar ratio of the citrated ion and the ferrous ion of the reducing agent aqueous solution with respect to the total atomic valence of the metal ion in the aqueous metal salt solution. . After the dropwise addition of the aqueous solution of the metal salt to the aqueous solution of the reducing agent is completed, the mixture is continuously stirred for 15 minutes to generate silver nanoparticles inside the mixed solution, thereby obtaining silver nanoparticle as a dispersed silver nanoparticle dispersion. The pH of the silver nanoparticle dispersion was 5.5, and the stoichiometric amount of silver nanoparticles in the dispersion was 5 g/liter. By placing the obtained silver nanoparticle dispersion at room temperature, the silver nanoparticles in the dispersion were sedimented, and the aggregates of the settled silver nanoparticles were separated by decantation. Deionized water is added to the separated silver nanoparticle aggregate to prepare a dispersion, and desalted by ultrafiltration, and then washed with methanol, and the content of metal (silver) is set to 50 mass. %. Thereafter, using a centrifugal separator, the centrifugal force of the centrifugal separator is adjusted, and silver nanoparticles having a primary particle diameter of 10 to 50 nm are separated by separating relatively large silver particles having a particle diameter of more than 10 nm. The particles were adjusted to have a number average of 71%. In other words, the ratio of the silver nanoparticles in the range of 1 〇 to 50 nm in the primary particle diameter is adjusted to 7 1% with respect to 1% by mass of the total silver nanoparticles. A silver nanoparticle dispersion stock solution is obtained. The obtained silver nanoparticles and the protective agent for sodium citrate are chemically modified. This silver nanoparticle dispersion dispersion was diluted with deionized water to obtain a silver nanoparticle dispersion liquid containing 100 mass% of silver nanoparticles having an average particle diameter of 20 nm: 100 cm3. -16-201234628 [Example 1] A silver nanoparticle dispersion liquid containing 5% by mass of silver nanoparticles was kept at 40 cm 3 . (: Adding an ethanol solution containing 5 wt% of tetraethoxy decane containing a transparent film raw material after vigorous stirring: 100 cm3 after adding 1% by mass of ammonia water as a catalyst: 5 cm3 'keep for 1 hour' to obtain The dispersion of the sensitizer of Example 1. The dispersion was subjected to ultrafiltration and then washed to obtain 7 g of the sensitizer of Example 1. The sensitizer of Example 1 was used to generate surface plasmon resonance. Further, the thickness of the transparent layer was 2 nm. [Example 2] A sensitizer of Example 2 was obtained in the same manner as in Example 1 except that an ethanol solution containing 20% by mass of tetraethoxysilane was added: 100 cm3. g. The sensitizer of Example 2 is a surface plasmon resonance, and the thickness of the transparent layer is 20 nm. [Example 3] In addition to using silver (III) acid instead of silver nitrate, silver nanoparticle is prepared. In the same operation, a gold nanoparticle dispersion liquid containing 5% by mass of the gold nanoparticles having an average particle diameter of 1 Onm was obtained: 100 cm 3 . The gold nanoparticle dispersion liquid containing 10% by mass of the gold nanoparticles was kept at 10 cm 3 . 50 ° C, at While vigorously stirring, a transparent film raw material acrylic acid: l〇cm3 was added, and azobisisobutyronitrile as a polymerization initiator was added: 〇·5 g for 1 hour to obtain a sensitizer containing Example 3. The dispersion was centrifuged and the solvent was removed, and the sensitizer of Example-17-201234628 3 was separated. Then, in order to "wash the sensitizer", ethanol was added again, and the sensitizer was stirred and stirred. After dispersion, the solvent was removed by centrifugation, and the washing was repeated three times to obtain the sensitizer of Example 3: 1 g. The sensitizer of Example 3 was to produce surface plasmon resonance 'the thickness of the transparent layer 5 nm [Examples 4 to 5, Reference Examples 1 to 2, and Comparative Example 1] The compositions shown in Table 1 were used to produce Examples 4 to 5, Reference Examples 1 to 2, and Comparative Example 1 sensitizers. As a raw material of P d , a raw material using palladium chloride ' C u is copper nitrate, and a raw material of polyethyl urethane is hexamethylene diisocyanate and polycarbonate polyol as a raw material of polyester. Use p-citric acid and ethylene glycol. 实施 'Examples 4 and 5 are the production tables The plasmonic resonance, the surface plasmon resonance was also produced in Reference Examples 1 to 2 and Comparative Example 1. [Table 1] Nanoparticle transparent layer composition (mass ratio) Particle size (nm) Composition (mass ratio) Thickness (nm) Example 1 Ag 20 SiO 2 2 Example 2 Ag 250 SiO 2 20 Example 3 Au 20 Acrylic Resin 5 Example 4 Ag: Pd = 90: 10 40 Polyurethane 10 Example 5 Ag: Cu = 90:10 100 Polyester 20 Reference Example 1 Ag 5 Si〇2 2 Comparative Example 1 Ag 20 I - Reference Example 2 Ag 100 Acrylic Resin 30 <<Manufacture of Composition for Sensitized Layer>> -18· 201234628 The obtained sensitizer: 10 parts by mass of the mixture was added to 90 parts by mass of a mixed solution containing water, ethanol and methanol, and the mixture was dispersed and mixed to prepare a composition for a sensitized layer. "Evaluation of Power Generation Efficiency" Table 2 shows the production conditions of the sensitized layer for evaluation. The "installation place" in Table 2 is the place where the sensitizer is formed, which is shown as the surface electrode side or the back electrode side; the "film thickness" is shown as the film thickness of the sensitized layer (unit: μηι); "Wet coating method j The method of applying the composition for sensitizing layer is shown here. 'Examples 1 and 4, Reference Example 1 is the structure shown in FIG. 4, Examples 2 and 5, and Comparative Example 1 are shown in FIG. The structure of the third embodiment and the reference example 2 is as shown in Fig. 3. The method for producing the solar cell to be evaluated is as follows. &lt;Case of Heterojunction Junction Solar Cell&gt; (Production of Photoelectric Conversion Unit) First, the photoelectric conversion unit 8 00 is produced as follows. As the substrate 81, an n-type single crystal germanium substrate having a resistance of about 1 Q.cm and a thickness of 300 μm is used, and the substrate 8 1 is subjected to a usual method. After the cleaning, the surface 81 of the substrate 81 and the back surface 81 are formed by etching to form a texture surface. Next, on the surface 81 A and the back surface 81 B of the substrate 81, a normal plasma CVD method is used to form The i-type amorphous germanium layer 82, the p-type amorphous germanium layer 83 and the i-type amorphous germanium layer 8 6 N-type amorphous tantalum layer 87. -19- 201234628 Next, the sensitized layers 1〇3 of Examples 1 and 4 and Reference Example 1 were formed over the p-type amorphous germanium layer 8 3. Next, in the n-type On the n-type amorphous germanium layer 87 and the sensitized layer 103 formed on both main surfaces of the single crystal germanium substrate 81, a back transparent electrode layer 88 and a surface composed of germanium having a thickness of 100 nm are formed by sputtering. Transparent electrode layer 84. For surface transparent electrode layer 84, sensitized layer 103, p-type amorphous germanium layer 83, i-type amorphous germanium layer 8, 2, n-type single In the designated area on the back surface and the surface of the photoelectric conversion unit 800 including the laminate of the wafer substrate 81, the i-type amorphous germanium layer 86, the n-type amorphous germanium layer 87, and the back transparent electrode layer 88, the network is used. The back surface electrode 89 and the surface electrode 85 of the comb shape are formed by a plate printing method. <The case of a super-straight type thin film solar cell> A method of manufacturing a tandem solar cell according to each embodiment of the present invention will be described. The material or film thickness of the constituent elements constituting the solar cell according to each of the examples is merely an example, but The invention is not limited to this. <In the case of a super-straight-type thin film solar cell> The cases of the second and fifth embodiments and the comparative example 1 will be described. First, a thickness of 50 nm is formed on the main surface of one side. a glass substrate 71 of a SiO 2 layer (not shown), and a transparent conductive film 61 is formed on the SiO 2 layer. This transparent conductive film 61 is patterned by a laser processing method, and is formed at -20-201234628. At the same time as the array, wirings which are electrically connected to each other were formed. Thereafter, the sensitized layers 101 of Examples 2 and 5 and Comparative Example 1 were formed on the transparent conductive film 61, respectively. Next, the power generation layer 40 is formed on the sensitization layer 101 by a plasma CVD method. In the power generation layer 40, p-type a-Si: Η (amorphous tantalum carbide) 43, i-type a-Si (amorphous germanium) 42, and n-type μα-Si are laminated in this order from the substrate 71 side. It is obtained by a film composed of (microcrystalline niobium carbide) 41. After the power generation layer 40 is subjected to pattern processing by a laser processing method, a back electrode layer (silver electrode layer) 21 having a thickness of 200 nm is sequentially formed on the power generation layer 40 by using an in-line magnetron sputtering apparatus. on. As a method for evaluating a solar cell unit cell, a lead wire is processed on a substrate subjected to a pattern processing by a laser processing method, and after the output characteristic and the short-circuit current (Jsc) at the time of confirming the IV characteristic curve, The photoelectric conversion layer obtained by the same manufacturing method as in the example was used, and the total number of the transparent conductive film and the back electrode layer was determined as a solar cell cell formed by sputtering, and the relative output was evaluated. . These results are shown in Table 2. Here, when all the solar cells formed by the sputtering method are described as being ultra-straight, the so-called super-straight solar cell unit is the sensitizer 11 and the sensitizing layer 101 from FIG. For the first step, a glass substrate 71 having a 50 nm-thick SiO 2 layer (not shown) is formed on the main surface of one side, and the surface of the 3 丨 02 layer is formed with irregularities and doped with A transparent conductive film (Sn02 film) 61 having a thickness of F (fluorine) of 800 nm. This transparent conductive film 61 is subjected to pattern processing by a laser processing method, and wirings which are electrically connected to each other are formed while forming an array. The power generation layer 40 is formed on the transparent conductive film 61 by a plasma CVD method, in connection with -21 - 201234628. The power generation layer 40 is laminated on the substrate 71 side in order. The type a_Si is obtained by a film composed of Η (non-crystalline lanthanum carbide) 43, i-type a-Si (amorphous yttrium) 42 and η-type gc-Si (microcrystalline yttrium carbide) 41. After the power generation layer 40 was subjected to pattern processing by a laser processing method, a back electrode layer (silver electrode layer) 21 having a thickness of 200 nm was sequentially formed on the power generation layer 40 by using an on-line magnetron sputtering apparatus. In the case of a heterojunction type solar cell, the sensitizer 11 and the sensitized layer 1〇1 are removed from FIG. 1, and i-type a-Si (amorphous) is used in the same manner as the super-straight type.矽) 32 and? The type of μο-Si (microcrystalline yttrium carbide) 33 and the transparent conductive film 60 are formed on the single crystal Si (n-type) 31 on which the A1 layer 20 has been formed, and then formed by etching after being formed by sputtering. Ag wiring that has been patterned. "Durability Test" A solar cell in which the initial power generation efficiency was measured was maintained at a temperature of 85 ° C, humidity: 85%, and 1,000 hours as a durability test. 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SS to (4) dig L cloud κ cvl shock* ssm is _·Ιΰ ΝΓΚ9## Ν—ΰ ia -23- 201234628 It can be seen from Table 1 that in the case of Examples 1 to 5, the initial performance of Jsc値 is high, There was no change in Jsc値 after the endurance test, which was a good result. On the other hand, in Comparative Example 1 in which the metal nanoparticle was not formed with the transparent layer, the effect of suppressing Ag diffusion was not obtained, and in Comparative Example 2, the sensitizing effect of the solar cell resonated by the surface plasmon was not observed. Further, Comparative Example 2, which did not contain a sensitizer, was lower in initial performance than in Example 1, Comparative Example 3 was lower in initial performance than in Example 2, and Comparative Example 4 was compared to Example 3 in initial performance. It is low. In the reference example 1 of the metal nanoparticles having an average particle diameter of 5 nm and the reference example 2 of 100 nm, the effect of suppressing Ag diffusion cannot be said to be sufficient. As described above, the sensitizer of the present invention can provide a solar cell having high power generation efficiency and good long-term stability. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] An example of a cross-sectional view of a heterojunction junction type solar cell using a sensitizer. 2] An example of a cross-sectional view of a super-straight type solar cell. FIG. 3 is another example of a cross-sectional view of a super-straight type solar cell. Fig. 4 is a view showing an example of a cross-sectional view of a heterojunction junction type solar cell. [Explanation of main component symbols] 1: Heterogeneous junction type solar cells 2, 3: Ultra-straight solar cells 1 〇, π, 1 2 : Sensitizer for solar cells • 24 - 201234628 100, 101, 102, 103: Solar energy Battery sensitized layer 20: A1 layer 2 1, 22: Back electrode layer 30, 40, 50: Power generation layer 31: Single crystal Si (n type) 41, 51: a-Si (n type) 32, 42, 52 : a-Si (i type) 33, 43, 53 : a-Si ( pM ) 60, 61, 62, 63 · Transparent conductive film 70 : Ag wiring 71 , 72 : Glass substrate 81 : η type single crystal germanium substrate 8 1 A : surface 8 1 B : back surface 82, 86 : i-type amorphous germanium layer 83 : p-type amorphous germanium layer 8 4 : surface side transparent electrode layer 8 5 : surface side electrode 87 : n-type amorphous矽 layer 8 8 : back side transparent electrode layer 8 9 = back side transparent electrode - 25 -

Claims (1)

201234628 VII. Patent application scope: 1. A sensitizer for solar cells, characterized in that the surface is a metal nanoparticle formed with a transparent layer to generate surface plasmon resonance. 2. The sensitizer for solar cells according to claim 1, wherein the metal of the metal nanoparticles is gold, silver, copper or palladium or selected from the group consisting of gold, silver, copper and palladium. Mixing at least two metals or alloys. 3. The sensitizer for a solar cell according to claim 1 or 2, wherein the metal nanoparticles have an average particle diameter of 5 to 300 nm. 4. The sensitizer for a solar cell according to any one of the preceding claims, wherein the transparent layer is SiO 2 , TiO 2 or Zr 02 , or a mixture of at least two selected from the group consisting of SiO 2 , Ti 2 and Zr 02 . The sensitizer for a solar cell according to any one of claims 1 to 3, wherein the transparent layer is an acrylic resin, a polycarbonate, a polyester, an alkyd resin, or a polyurethane. At least one selected from the group consisting of acrylic urethane, polystyrene, polycondensation, polyamine, polyethyl alcohol, polyvinyl acetate, cellulose, and siloxane polymer . The sensitizer for a solar cell according to any one of claims 1 to 5, wherein the transparent layer has a thickness of 1 to 20 nm. A sensitizer for a solar cell, which comprises the sensitizer for a solar cell and a dispersion medium according to any one of claims 1 to 6. A sensitizing layer for a solar cell, which comprises the sensitizer for a solar cell according to any one of the first to sixth aspects of the invention. -26- 201234628 9 · A solar cell comprising a sensitized layer for a solar cell as claimed in claim 8 of the patent application. 10. A method for producing a sensitized layer for a solar cell, characterized in that the composition for a sensitized layer for a solar cell according to claim 7 of the patent application is applied to a power generation layer of a solar cell by a wet coating method On the upper, transparent conductive film or on the electrode. 11. The method for producing a sensitized layer for a solar cell according to claim 10, wherein the wet coating method is a spray coating method, a dispensing method, a spin coating method, a knife coating method, or a narrow method. Any one of a slit coating method, an inkjet coating method, a screen printing method, a lithography method, or a die coating method. -27-