JP5280970B2 - Solar cell having metal nanoparticle dispersed film on its surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell having high energy conversion efficiency by increasing absorbency at the top surface of the solar cell and reducing the reflectance thereof. <P>SOLUTION: The solar cell has a metal nanoparticle dispersion film formed on its light-receiving surface and having metal nanoparticles with a surface plasmon absorption peak dispersed in an organic or inorganic material. A method of manufacturing the solar cell comprises applying an application solution, obtained by dispersing and dissolving both of metal nanoparticles with a surface plasmon absorption peak and an organic or inorganic material in a dispersion medium, to the light-receiving surface to form a metal nanoparticle dispersion film on the light-receiving surface. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a solar cell having a metal nanoparticle-dispersed film on the surface, and more particularly, increases absorbance and / or reflectivity by using absorption and / or scattering by surface plasmons of the metal nanoparticle-dispersed film. This relates to a solar cell in which the conversion efficiency is improved.

  Solar cells are attracting attention as energy systems that can solve the depletion of energy resources and environmental pollution, but further high efficiency and low cost are required for widespread use. In order to increase efficiency, it is necessary to efficiently convert the solar energy irradiated to the surface of the photoelectric conversion layer into electrical energy by increasing the absorbance or decreasing the reflectance of the surface of the photoelectric conversion layer of the solar cell. is there.

  Therefore, there is a technique for covering the light receiving surface of the solar cell with an antireflection film in order for the solar cell to absorb sunlight efficiently. Conventionally, as this type of antireflection film, a technique is known in which a PVD method, a vapor deposition method, a spray method, a dip method, or the like is used to apply an antireflection film material to the surface, followed by heat treatment. A technique for forming a silicon nitride film containing hydrogen on a light receiving surface of a solar cell by plasma CVD is also known (Patent Document 1). In addition, a passivation effect is also known in which hydrogen in a silicon nitride film, which is an antireflection film of a solar cell, is diffused into the silicon substrate of the solar cell, thereby increasing the efficiency of the solar cell (Patent Document 2).

  Moreover, in order to absorb sunlight efficiently, the technique using a light absorption layer (light absorption thin film) is also known (for example, patent documents 3-5).

  On the other hand, in metal nanoparticles, plasmons are localized on the surface, and the electric field of near-infrared to near-ultraviolet light and the localized (surface) plasmons are coupled to cause light absorption. This phenomenon is known as Surface Plasmon Resonance (SPR). As a result, a locally enhanced electric field is generated, and light energy is converted to surface plasmons, resulting in metal Light energy is stored on the nanoparticle surface. There are also resonance wavelengths depending on the particle diameter and the dielectric constant of the surrounding medium.

  Non-Patent Document 1 and Patent Document 6 by the inventors of the present application are known as utilizing this phenomenon for increasing the absorbance of solar cells and increasing energy conversion efficiency. Non-Patent Document 1 describes that the absorption coefficient of the dye N3Dye used in the dye-sensitized solar cell is increased up to 149 times by using silver nanoparticles. Further, Patent Document 6 describes that a dye-sensitized solar cell in which silver nanoparticles are supported in a titania nanoporous film was manufactured using this increasing effect, and conversion efficiency was successfully improved.

  Further, in Patent Document 7, a light irradiation part having a dielectric constant different from the dielectric constant of the metal film is deposited on the metal film to which the photoresponsive molecule is fixed. A solar cell using surface plasmon resonance at the interface is described, and Patent Document 8 describes a dye-sensitized solar cell in which metal fine particles regularly arranged in a laminated structure of metal fine particles and semiconductor fine particles are arranged. A technique is described in which surface plasmon resonance is enhanced by interaction to improve the absorption coefficient of a photosensitizer adsorbed on metal fine particles.

  However, although all are common in that surface plasmons are used, the configuration and form are completely different from those of the solar cell of the present invention, and applicable forms are extremely limited. It was. Moreover, in this invention, it is a solar cell which has a thin film which also has the antireflection effect using the scattering by surface plasmon in addition to the light absorbency increasing effect by surface plasmon absorption.

  In recent years, the demand for an increase in the energy conversion efficiency of solar cells is extremely high, and the known techniques described above are still insufficient in increasing the absorbance and reducing the reflectance, and are also for selecting the form of the solar cell, Further improvements were desired.

JP 2000-299482 A JP 2003-273382 A JP 2006-228867 A JP 2009-054936 A JP 2009-135517 A JP 2007-265694 A Japanese Patent Laid-Open No. 10-340742 JP 2007-335222 A

M. Ihara et al, J. Phys. Chem. B 101, 5153, (1997)

  The present invention has been made in view of the above-described background art, and its problem is to provide a solar cell having high energy conversion efficiency by increasing the absorbance (Absorbance) of the surface of the solar cell, reducing the reflectance (Reflectance), and the like. There is to do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that if a film in which metal nanoparticles having a surface plasmon absorption peak are dispersed is provided on the surface of the solar cell, the absorbance is greatly increased by surface plasmon resonance. And found that high energy conversion efficiency can be achieved. In addition, by controlling the type, average particle diameter, dispersion state, arrangement state, etc. of the metal nanoparticles, the component ratio, the dielectric constant of the film, the film thickness, etc., the plasmon absorption peak position, absorbance, reflectance, etc. As a result, the present invention has been completed.

  That is, the present invention provides a solar cell characterized in that a light-receiving surface has a metal nanoparticle dispersion film in which metal nanoparticles having a surface plasmon absorption peak are dispersed in an organic or inorganic material.

  The present invention also provides a coating solution obtained by dispersing and dissolving a metal nanoparticle having a surface plasmon absorption peak and an organic or inorganic material in a dispersion medium. The present invention provides a method for manufacturing a solar cell, characterized by forming a particle dispersion film.

  According to the present invention, there is provided a solar cell having high energy conversion efficiency, which solves the above-mentioned problems and problems, and achieves an increase in absorbance, a reduction in reflectance, etc., due to an electric field enhancement effect by surface plasmons of metal nanoparticles. can do. Moreover, the solar cell which has a metal nanoparticle dispersion film | membrane which also has the antireflection effect using scattering by surface plasmon can be provided.

  In addition, according to the present invention, the type of solar cell to be applied is not limited, since a film in which metal nanoparticles are dispersed in an organic or inorganic material only needs to be applied and formed on the light receiving surface. It can be applied to many types of solar cells, such as semiconductor solar cells such as compound semiconductor solar cells, organic solar cells, and the like.

  Also, the type of metal nanoparticles, average particle size, dispersion state, arrangement state, etc., and the dielectric constant and content ratio of the organic or inorganic material that is the matrix in which the metal nanoparticles are dispersed, the film thickness of the metal nanoparticle dispersion film Since the plasmon absorption peak wavelength, absorbance, reflectance, and the like can be controlled by controlling etc., the absorbance and reflectance can be controlled in a well-balanced manner in the wavelength of sunlight from near infrared to near ultraviolet.

It is an absorption spectrum of the metal nanoparticle dispersion film used in the solar cell of the present invention. It is a reflection (Reflectance) spectrum of the metal nanoparticle dispersion film | membrane used for the solar cell of this invention. For comparison, it is a reflection spectrum of a single crystal silicon substrate (silicon wafer) alone and a PEG not containing metal nanoparticles coated on a silicon wafer. It is a conceptual diagram which shows the effect of the light absorbency increase of the solar cell by the metal nanoparticle dispersion film in this invention.

  Hereinafter, the present invention will be described, but the present invention is not limited to the following specific embodiments, and can be arbitrarily modified within the scope of the technical idea.

  The solar cell of the present invention has a metal nanoparticle dispersion film having a surface plasmon absorption peak on the surface. With such a metal nanoparticle-dispersed film, the absorbance can be increased or the reflectance can be decreased. In the present invention, the “metal nanoparticle” is a metal particle in which plasmon can be localized on the surface, and the number average particle diameter measured by the dynamic light scattering method is in the range of 0.1 to 1000 nm. Say things. Although the preferable range of the number average particle diameter depends on the kind of metal, it is 1 to 500 nm, and a particularly preferable range is 10 to 200 nm. If the number average particle size is too small, it will be difficult to prepare metal nanoparticles, the plasmon absorption peak of the metal nanoparticle dispersion film will shift to the short wavelength side, and a sufficient absorbance increasing effect will not be obtained, and the reflectance will be sufficiently reduced There are cases where it is no longer. On the other hand, if the number average particle size is too large, the loss due to the shadow of the metal nanoparticles increases, the surface plasmon absorption peak becomes small, the effect of increasing the absorbance by the metal nanoparticle dispersed film cannot be obtained, etc. is there.

  The metal type of the metal nanoparticles is not particularly limited, and examples thereof include silver (Ag), gold (Au), platinum (Pt), copper (Cu), lead (Pb) and the like.

  The solar cell of the present invention has on its surface a metal nanoparticle dispersed film in which the metal nanoparticles are dispersed in an organic or inorganic material. "Organic or inorganic material" functions as a binder or matrix for the above metal nanoparticles, and is essential for the appearance of the coating properties when forming a metal nanoparticle dispersion film, the dispersibility of metal nanoparticles, etc. is there. Such “organic or inorganic material” also contributes to adjustment of dielectric constant, reduction of reflectance, increase of optical path length, and the like.

  In the solar cell of the present invention, the metal nanoparticles are not attached to the surface by vapor deposition or the like, but the organic or inorganic material is used as a binder or matrix of the metal nanoparticles and dispersed in the organic or inorganic material. Metal nanoparticles are applied to the light receiving surface of a solar cell.

  The organic or inorganic material is not particularly limited as long as it functions as a binder or matrix of the metal nanoparticles, but among them, the organic material is suitably dissolved in the dispersion medium of the metal nanoparticles and functions as a binder. Organic polymers are preferred. The organic polymer is not particularly limited, and specifically, for example, ethylene oxide polymers such as polyethylene glycol and polypropylene glycol; hydrophilic vinyl polymers such as polyvinyl alcohol and polyvinyl pyrrolidone; hydrophilicity derived from natural products such as starch and carboxymethyl cellulose Polymers; Thermoplastic polymers such as polyester and polycarbonate; Vinyl such as poly (meth) acrylic acid, poly (meth) acrylic ester, polystyrene, polyacetal, polyvinyl acetate, polyvinyl chloride, polyacrylonitrile, and copolymers thereof System polymers; and the like.

  The inorganic material is not particularly limited, and examples thereof include silica, titania, and glass.

  In the present invention, a method for forming a metal nanoparticle dispersion film containing at least “metal nanoparticles” and “organic or inorganic material” on the light receiving surface of the solar cell is not particularly limited, but a coating solution is applied. Is preferred. Specifically, it is particularly preferable to form a metal nanoparticle-dispersed film by applying a coating solution in which surface-modified metal nanoparticles and an organic or inorganic material are dispersed and dissolved in a dispersion medium to the light-receiving surface of a solar cell. preferable.

  The method for preparing the dispersion of metal nanoparticles is not particularly limited, but it is preferably prepared in the liquid using a phase transfer catalyst as described below. The dispersion of metal nanoparticles can be obtained by substituting the dispersion medium for the obtained dispersion of metal nanoparticles, if necessary, so add “organic or inorganic material” to it and apply it as it is. Can be liquid.

  Metal nanoparticles with a surface plasmon absorption peak are dispersed or dissolved in a dispersion medium together with an organic or inorganic material serving as a binder or matrix, and applied to the light-receiving surface of the solar cell and dried to form a metal nanoparticle dispersion film. Then, the film can increase the absorbance and control the reflectance and the like, and as a result, the energy conversion efficiency of the solar cell can be improved. Since the metal nanoparticle dispersion film can be formed on any surface simply by coating and drying, the present invention is extremely versatile with respect to the types of solar cells that can be applied.

Although the preparation method of a metal nanoparticle is not specifically limited, For example, the following method is mentioned. That is, using a phase transfer catalyst, a metal salt dissolved in an aqueous phase is dispersed as metal ion fine particles in an organic phase such as chloroform in contact with the aqueous phase, and then a surface modifying compound is added to inhibit growth, followed by the aqueous phase. The metal ions are reduced to metal nanoparticles by a reducing agent such as NaBH ₄ .

  The surface modifying compound is important for providing a suitable peripheral dielectric constant in addition to stopping the growth of the metal nanoparticles as described above. In order to obtain a stronger electric field enhancing effect, the type of the surface modifying compound is preferably determined from its dielectric constant.

  As the surface modifying compound, those having an appropriate dielectric constant are preferable in order to efficiently obtain an electric field enhancing effect. Specifically, a compound having one or more functional groups that form a chemical bond with a metal (ion) is preferable. As such a functional group, for example, a mercapto group or an amino group is preferable. The surface modification compound preferably further has one or more parent dispersion medium groups such as a carboxyl group and a hydroxyl group.

Specific examples of the surface modifying compound include those represented by the following general formula (1) or (2).
X-R-SH (1)
X—R—NH ₂
(2)
[In Formula (1) and Formula (2), R represents a linear or branched alkylene group, and X represents a carboxyl group or a hydroxyl group. ]

  R represents a linear or branched alkylene group, and the number of carbon atoms of the alkylene group is preferably determined so as to give a peripheral dielectric constant that can sufficiently exert an electric field enhancing effect. Although carbon number of an alkylene group does not have limitation in particular, 1-24 are preferable and 2-20 are especially preferable. Specific examples of suitable surface modification compounds represented by formula (1) include 3-mercaptopropionic acid and 16-mercaptohexadecanoic acid.

  The dispersion medium for dispersing / dissolving the surface-modified metal nanoparticles and the organic or inorganic material to form a coating solution may use the organic phase liquid as it is, or the dispersion medium may be replaced. . Moreover, as a dispersion medium (after dispersion medium substitution) including the case where metal nanoparticles are formed by a method other than the above method using a phase transfer catalyst, any organic or inorganic material can be dissolved or dispersed. There is no particular limitation, and water; alcohols such as methanol, ethanol and propanol; ketones such as acetone; dimethylformamide; dimethyl sulfoxide; and carbonates such as ethylene carbonate and propylene carbonate; A non-hydrophilic dispersion medium that is not compatible with water in an arbitrary ratio may be used.

  As will be described later, the metal nanoparticle-dispersed film is applicable not only to semiconductor solar cells but also to organic solar cells. Therefore, when applied directly to a photoelectric conversion layer of an organic solar cell, the coating liquid, that is, the above The dispersion medium preferably does not erode the photoelectric conversion layer.

The mass ratio of “metal (a) in metal nanoparticles” and “organic or inorganic material (B) functioning as a binder or matrix of metal nanoparticles” constituting the metal nanoparticle-dispersed film is the dispersion state of metal nanoparticles. It affects the array state, the distance between metal nanoparticles, etc., affects the electric field enhancement effect, and changes the plasmon absorption peak wavelength, absorbance, reflectance, etc., so that they are determined to be optimal. Although there is no particular limitation, a / B = 1 × 10 ⁻⁹ to 1 × 10 ⁻³ is preferable, and a / B = 1 × 10 ⁻⁸ to 1 × 10 ⁻⁴ is particularly preferable.

In addition, "the whole metal nanoparticles (A) including particle-forming substances such as surface modifying compounds" and "organic or inorganic materials (B) that function as a binder or matrix of metal nanoparticles" that constitute the metal nanoparticle dispersion film Since the mass ratio also affects the physical properties, they are determined so as to be optimal. Although there is no particular limitation, A / B = 1 × 10 ⁻⁸ to 1 × 10 ⁻² is preferable, and A / B = 1 × 10 ⁻⁷ to 1 × 10 ⁻³ is particularly preferable.

  The present invention is characterized by having the metal nanoparticle dispersion film on the light receiving surface. The “light receiving surface” refers to a surface on the side where sunlight enters in the solar cell. “Having a metal nanoparticle dispersion film on the light-receiving surface” means that the metal nanoparticle dispersion film is directly present on the surface of the photoelectric conversion layer of the solar cell. However, it is preferable that the metal nanoparticle-dispersed film is directly present on the surface of the photoelectric conversion layer of the solar cell from the viewpoint of energy transfer and the like.

  Since the metal nanoparticle-dispersed film in the present invention amplifies light energy, it is essential to exist on the surface side where sunlight enters in a solar cell, and the surface of such a photoelectric conversion layer is based on the principle of the present invention. , P layer, n layer, i layer, etc.

  There are no particular restrictions on the method of applying the “coating liquid in which the surface-modified metal nanoparticles and organic or inorganic material are dispersed / dissolved in a dispersion medium” to the light-receiving surface. Specifically, for example, spin coating, spraying, etc. Examples thereof include a coating method, a dip coating method, a curtain coating method, an ink jet method, a roll coating method, a blade coating method, a screen printing method, and a die coating method.

  After coating, the dispersion medium is distilled off (dried). After the dispersion medium is distilled off, a post-treatment such as a heat treatment may be added as necessary. When the “organic or inorganic material” is an organic polymer, the metal nanoparticle-dispersed film is usually completed simply by distilling off the dispersion medium.

  The thickness of the metal nanoparticle dispersed film after the dispersion medium is distilled off (dried) is not particularly limited, but is preferably 1 nm to 10000 nm (10 μm), more preferably 2 nm to 3000 nm (3 μm), and 3 nm to 1000 nm (1 μm). Is particularly preferred. If the metal nanoparticle dispersion film is too thick, the distance between the metal nanoparticles and the surface of the photoelectric conversion layer may be too large, which may inhibit energy transfer. If it is too thin, sufficient antireflection The effect may not be obtained or it may be difficult to form a continuous film.

  Kind of metal nanoparticles, average particle size, dispersion state, arrangement state, distance between metal nanoparticles, etc., and dielectric constant of surface modifying compound, dielectric constant of organic or inorganic material that is matrix in which metal nanoparticles are dispersed By controlling the ratio of “metal nanoparticles” and “organic or inorganic material”, the thickness of the metal nanoparticle dispersion film, the viscosity of the coating solution, etc., the electric field enhancement effect, plasmon absorption peak wavelength, absorbance, reflectance, etc. Therefore, it is possible to control the absorbance and the reflectance in a balanced manner in the wavelength region of sunlight.

  The metal nanoparticle-dispersed film in the present invention is suitably applied to, for example, silicon solar cells such as single crystal silicon solar cells, polycrystalline silicon solar cells, and amorphous crystal silicon solar cells; compound semiconductor solar cells; organic solar cells; it can.

  In the present invention, the local electric field enhancement effect by the surface plasmon of the metal nanoparticles is used to increase the absorbance of the semiconductor and the dye, thereby improving the conversion efficiency of the solar cell. FIG. 4 shows a conceptual diagram of the principle of operation when the metal nanoparticle-dispersed film is applied to a (semiconductor) solar cell. In the present invention, the surface plasmon of metal nanoparticles can be used for increasing the efficiency of solar cells such as semiconductor solar cells. As shown in the examples, the silver nanoparticle-dispersed film has an absorption peak derived from surface plasmons at 400 to 500 nm, and a reduction in reflectance was observed. Therefore, the local electric field enhancement effect of surface plasmons (light that is locally stronger than the incident light (near-field light) is generated) increases the absorbance and prevents reflection, thereby increasing the efficiency of the solar cell. For example, the energy conversion efficiency can be improved only by applying the metal nanoparticle dispersion film to a semiconductor solar battery such as a silicon solar battery.

  Specifically, the local electric field enhancement effect can increase the absorbance of a semiconductor thin film or the like. For example, the reduction of loss due to carrier recombination (a factor that reduces photocurrent) by reducing the thickness of a semiconductor film can be achieved. It becomes possible, and high efficiency can be realized.

  In the method of selectively etching the surface of the solar cell to form a texture structure and realizing the antireflection effect, defects may be introduced into the surface of the semiconductor solar cell. However, in the present invention, defects are not introduced because they are simply applied and dried under mild conditions such as room temperature.

  In the present invention, after the above-described metal nanoparticle dispersion film is provided on the light receiving surface of the solar cell, another layer such as an antireflection layer may be further provided thereon.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

Example 1

An aqueous phase in which 0.15 g of silver nitrate (AgNO ₃ ) was dissolved in water and an organic phase in which tetraoctylammonium bromide ((C ₈ H ₁₇ ) ₄ NBr) as a phase transfer catalyst was dissolved in chloroform were contained in a container. After stirring at 20 ° C. for 1 hour to move silver ions to the organic phase, the aqueous phase was removed. Next, 0.23 g of 16-mercaptohexadecanoic acid was added to the organic phase as a surface modification compound and stirred for 15 minutes. Thereafter, an aqueous solution of NaBH ₄ as a reducing agent was mixed with the organic phase and stirred at room temperature for 12 hours. Thereby, silver ions in the organic phase are reduced, and a liquid in which silver nanoparticles whose surface is coated with 16-mercaptohexadecanoic acid (hereinafter abbreviated as “thiol”) is dispersed is prepared. It was done.

  After removing the aqueous phase, “surface-modified silver nanoparticles” were precipitated from the liquid by centrifugation, and after removing the supernatant, ethanol was added to obtain a liquid using ethanol as a dispersion medium. Next, polypropylene glycol (weight average molecular weight 500000) (hereinafter abbreviated as “PEG”), which is an “organic or inorganic material” that functions as a binder or a matrix, was added to the solution to prepare a coating solution.

  Each component was used so as to have a value as shown in Table 1 as a result. The number average particle diameter of the silver nanoparticles was determined by a dynamic light scattering method using ELS-Z2 manufactured by Otsuka Electronics Co., Ltd.

  By applying the coating solution onto a quartz plate and a single crystal silicon substrate (silicon wafer) by a spin coating method, a silver nanoparticle dispersed film was produced. At this time, the concentration of silver nanoparticles was changed by changing the amount of ethanol as a dispersion medium, and the viscosity of the coating solution was changed by changing the amount of PEG to be added.

  About the produced silver nanoparticle dispersion film | membrane, the light absorption spectrum was measured in accordance with the conventional method, and it observed using the scanning electron microscope (SEM).

表１中、銀ナノ粒子の質量には、銀以外に表面修飾化合物等の銀ナノ粒子を構成する成分の質量も含む。

In Table 1, the mass of the silver nanoparticles includes the mass of components constituting the silver nanoparticles such as the surface modification compound in addition to silver.

  Sample No. The light absorption spectra on the quartz plates 1, 2 and 3 and the reflection spectrum on the single crystal silicon substrate are shown in FIGS. 1 and 2, respectively. The light absorption spectrum when only PEG was applied on a quartz plate at 100 to 200 nm was Absorbance = 0.00 in the entire wavelength region of 400 to 650 nm in FIG. Further, FIG. 3 shows a reflection spectrum when only PEG is applied on a single crystal silicon substrate at 100 to 200 nm together with the reflection spectrum of the single crystal silicon substrate itself.

  From the light absorption spectrum of FIG. 1, absorption peaks derived from the surface plasmons of the silver nanoparticles were observed. In the light absorption spectrum by the surface plasmon, the sample No. Although 1 showed the largest absorbance, it is thought that this is because the particle size is smaller than other samples. It is also considered that light absorption is more dominant than scattering.

  In the reflection spectrum of FIG. 2, the antireflection effect appeared in all the silver nanoparticle dispersion films. In the wavelength region substantially the same as the surface plasmon absorption peak in FIG. This is considered to be due to light absorption of silver nanoparticles. Therefore, if the local electric field enhancement effect by this surface plasmon absorption is utilized, the light absorption of the silicon substrate can be increased.

  On the other hand, sample No. In No. 1, no decrease in reflectance was observed near 700 nm. This is considered to be due to the interference effect of light. Sample No. In 2, the decrease in reflectance on the longer wavelength side than the peak wavelength in absorbance was significant. The cause of this was that light scattering contributed due to the large particle size. Since the concentration is higher than 3, the particles are close to each other, the apparent particle size is larger, the contribution of light scattering is further increased, or the silver nano-particles formed by aggregation of the nanoparticles Two points can be considered that fine irregularities on the surface of the particle dispersion film caused an antireflection effect.

  From the above, in the preparation of the silver nanoparticle dispersion film, the surface of the silver nanoparticle dispersion film was changed by changing the particle size and concentration of the silver nanoparticles, the viscosity of the coating solution, the content ratio of silver nanoparticles and PEG, the film thickness, etc. As a result of measuring the absorbance and reflectance caused by plasmons, it was considered that the production conditions, configuration, etc. of the metal nanoparticle dispersion film suitable for high efficiency of the solar cell can be determined.

  The metal nanoparticle dispersion film obtained by optimizing various requirements can have high absorbance and low reflectance in the wavelength region of sunlight. It was found that a solar cell with improved conversion efficiency can be obtained.

  Since the solar cell of the present invention has a metal nanoparticle dispersion film on its light receiving surface, if the local electric field enhancement effect due to surface plasmon absorption of the metal nanoparticle dispersion film is used, the absorbance of the solar cell surface is increased and reflected. Since a solar cell with high energy conversion efficiency can be provided by reducing the rate or the like, it is widely used in the field of manufacturing solar cells.

Claims (4)

  A solar cell comprising a metal nanoparticle-dispersed film in which metal nanoparticles having a surface plasmon absorption peak are dispersed in an organic or inorganic material on a light receiving surface.   2. The metal nanoparticle dispersion film according to claim 1, wherein the metal nanoparticle dispersion film is obtained by coating a light receiving surface with a coating solution in which surface-modified metal nanoparticles and an organic or inorganic material are dispersed and dissolved in a dispersion medium. Solar cell.   The solar cell according to claim 1 or 2, wherein the organic or inorganic material is an organic polymer.   A coating solution obtained by dispersing and dissolving a metal nanoparticle having a surface plasmon absorption peak and an organic or inorganic material in a dispersion medium is applied to the light receiving surface to form a metal nanoparticle dispersed film on the light receiving surface. A method for manufacturing a solar cell.

Images