JP2010278148A - Photovoltaic apparatus and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photovoltaic apparatus capable of absorbing solar light more efficiently even in a photovoltaic apparatus having a structure in which strip-like unit cells are connected in series via an isolation trench on a translucent insulating substrate. <P>SOLUTION: In a photovoltaic apparatus, a cell 10 including a surface electrode layer 11 formed by a transparent conductive material, a photoelectric conversion layer 12 including a semiconductor material that converts light into electricity, and a back surface electrode layer 14 consisting of a conductive material, is formed on an insulating translucent substrate 2. The back surface electrode layer 14 of the cell 10 is connected with the surface electrode layer 11 of an adjacent cell 10 in an isolation trench 22 formed between the cell and the photoelectric conversion layer 12 of the adjacent cell 10, and the plurality of cells 10 are connected in series. The photovoltaic apparatus has a lamination light reflection film 15 in which two or more kinds of material having a refractive index different from each other so as to cover at least the side and the bottom surface of the isolation trench 22. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photovoltaic device that converts light energy into electrical energy and a method for manufacturing the photovoltaic device.

  Conventional photovoltaic devices composed of thin films are required to have a structure capable of increasing the amount of light absorbed by the photoelectric conversion layer in order to improve the conversion efficiency. For example, a structure that allows more light to be absorbed by increasing the film thickness of the photoelectric conversion layer, which is mainly composed of semiconductor layers that perform photoelectric conversion, and unevenness on the substrate on which light is incident to diffuse light A structure for providing light, a structure for diffusing and reflecting light on the substrate or in the photoelectric conversion layer of the solar cell and on the stacked interface of the stacked solar cell have been proposed (for example, see Patent Document 1). In the photovoltaic device having such a structure, a light confinement effect can be obtained for light transmitted without being absorbed in the same direction as the light incident direction.

Japanese Patent No. 3,258,680 JP 2008-305945 A

  By the way, in recent years, a transparent electrode layer formed in a strip shape is formed on a translucent insulating support, a photoelectric conversion layer and a back electrode layer are laminated thereon, and then a separation groove is formed by a laser scribing method. A photovoltaic device having a structure in which a plurality of strip-shaped cell regions are divided into a plurality of strip-shaped cell regions and electrically connected in series has been proposed (for example, see Patent Document 2). However, no countermeasure has been taken for light leaking from the side surface facing the separation groove of the back electrode layer of the photovoltaic device described in Patent Document 2. As a result, there is a problem that a loss is caused by the amount of light leaking from the side surface facing the separation groove of the back electrode.

  The present invention has been made in view of the above, and even in a photovoltaic device having a structure in which strip-shaped unit cells are connected in series via a separation groove on a translucent insulating substrate, sunlight is more efficiently produced. It is an object of the present invention to obtain a photovoltaic device that can be absorbed in the water and a manufacturing method thereof.

  To achieve the above object, a photovoltaic device according to the present invention includes a first electrode layer formed of a transparent conductive material on a light-transmitting substrate and a semiconductor material that converts light into electricity. A cell including a photoelectric conversion layer and a second electrode layer made of a conductive material is formed, and the second electrode layer of the cell is formed between the photoelectric conversion layer of an adjacent cell. In the photovoltaic device in which a plurality of the cells are connected in series so as to cover at least the side surface and the bottom surface of the separation groove in the separation groove and connected to the first electrode layer of the adjacent cell. And a laminated light reflecting film in which two or more kinds of materials having different refractive indexes are laminated.

  According to the present invention, since the separation groove is covered with the laminated light reflecting film, the light leaking laterally from the side surface of the photoelectric conversion layer exposed by forming the separation groove by a method such as a laser scribing method or an etching method. Can be returned to the photoelectric conversion layer again. As a result, the power generation efficiency can be improved. Also, by making the laminated light reflecting film a multilayer film, the reflectance for light of a specific wavelength can be made higher than in the case of a single layer film, more effectively confining light, and generating efficiency can be improved. There is also an effect that it can be improved.

FIG. 1 is a sectional view schematically showing an example of the structure of a photovoltaic device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an enlarged part of the laminated light reflecting film. FIG. 3 is a diagram illustrating a result of calculating the reflectance of the laminated light reflecting film using a general multiple reflection model of light. FIG. 4 is a diagram showing the absorption coefficient of amorphous silicon. FIG. 5 is a diagram showing the quantum efficiency of the amorphous silicon solar cell obtained by simulation. FIG. 6A is a cross-sectional view schematically showing an example of the procedure of the manufacturing method of the photovoltaic device according to this embodiment (No. 1). 6-2 is sectional drawing which shows typically an example of the procedure of the manufacturing method of the photovoltaic device by this embodiment (the 2). 6-3 is sectional drawing which shows typically an example of the procedure of the manufacturing method of the photovoltaic device by this embodiment (the 3). 6-4 is sectional drawing which shows typically an example of the procedure of the manufacturing method of the photovoltaic device by this embodiment (the 4). 6-5 is sectional drawing which shows typically an example of the procedure of the manufacturing method of the photovoltaic device by this embodiment (the 5). 6-6 is sectional drawing which shows typically an example of the procedure of the manufacturing method of the photovoltaic device by this embodiment (the 6).

  Hereinafter, a photovoltaic device and a manufacturing method thereof according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. Moreover, sectional views of the photovoltaic devices used in the following embodiments are schematic, and the relationship between the thickness and width of the layers, the ratio of the thicknesses of the layers, and the like are different from the actual ones.

  FIG. 1 is a sectional view schematically showing an example of the structure of a photovoltaic device according to an embodiment of the present invention. In this photovoltaic device 1, a plurality of unit solar cells (hereinafter simply referred to as cells) 10 are arranged in a predetermined direction (left and right in the figure) on an insulating translucent substrate 2 such as a glass substrate or a resin substrate. Connected in series. Each cell 10 is formed by a photoelectric conversion element in which a front surface electrode layer 11, a photoelectric conversion layer 12, a back surface reflection layer 13, and a back surface electrode layer 14 are sequentially stacked. The surface electrode layer 11 of a certain cell 10 is connected to the back electrode layer 14 of one adjacent cell 10 (left adjacent in FIG. 1), and the back electrode layer 14 is connected to the other adjacent (right adjacent in FIG. 1). And (b) connected to the surface electrode layer 11 of the cell 10. Then, the laminated light reflecting film 15 is formed so as to cover the upper surface and side surfaces of the cells 10 connected in series.

  Further, for example, the laminated light reflecting film 15 is removed from a part on the back electrode layer 14 of the cell 10 at both ends in the series direction to provide an external electrode connection portion, and the external electrode 16 is formed in the external electrode connection portion. Further, an extraction wiring 17 is attached to the external electrode 16. And the photoelectric conversion element on the insulating translucent board | substrate 2 formed in this way is sealed with sealing resin 18, such as an ethylene vinyl acetate copolymer (EVA). Here, a region on the insulating translucent substrate 2 where the photoelectric conversion layer 12 is formed is referred to as a cell formation region R. Moreover, in this photovoltaic apparatus 1, the surface on the light incident side is referred to as the front surface, and the surface opposite to the front surface is referred to as the back surface. Below, the detail of each layer which comprises a photoelectric conversion element is demonstrated.

  The surface electrode layer 11 is made of a transparent conductive material such as zinc oxide, tin oxide, or ITO (Indium Tin Oxide). The surface electrode layer 11 is formed separately for each cell 10 by the separation groove 21, but the formation position thereof does not coincide with the cell formation region R, and a part of the cell formation region R to which the surface electrode layer 11 belongs, It is formed across a part of the cell forming region R adjacent (adjacent to the left side in the example of this figure). That is, in the cell formation region R, the surface electrode layer 11 that functions in the cell formation region R and the surface electrode layer 11 that functions in the adjacent cell formation region R are arranged at a distance. For example, in FIG. 1, a surface electrode layer 11 constituting a part of the photoelectric conversion element of the cell 10 is formed in a substantially left half region of a certain cell forming region R. In the region, a surface electrode layer 11 constituting a part of the photoelectric conversion element of the cell 10 adjacent to the right is formed.

The photoelectric conversion layer 12 has a pn junction or a pin junction, and is configured by a layer including a single layer or a plurality of stacked thin film semiconductor layers that generate power by incident light. As the thin film semiconductor layer, hydrogenated amorphous silicon, microcrystalline silicon, amorphous silicon germanium, microcrystalline silicon germanium, amorphous silicon carbide, microcrystalline silicon carbide, or the like can be used. Further, when the photoelectric conversion layer 12 is composed of a laminated film of a plurality of thin film semiconductor layers, conductivity is improved by doping a transparent conductive film such as ITO or ZnO or impurities between different thin film semiconductor layers. A silicon compound film such as SiO ₂ or SiN may be inserted as an intermediate layer.

  Since the back surface reflection layer 13 is formed between the photoelectric conversion layer 12 and the back surface electrode layer 14, a conductive film is preferable, and a higher reflectance is more preferable. For example, Al or Ag having a reflectance of 90% or more at the time of vertical incidence at a wavelength of 650 nm is desirable. Moreover, since the reflectance of Ag is higher than that of Al from the visible light region to the near infrared region, it is desirable to use Ag as the back surface reflection layer 13.

  The photoelectric conversion layer 12 and the back surface reflection layer 13 are formed separately for each cell 10 by the separation groove 22, and the formation position thereof coincides with the cell formation region R.

  The back electrode layer 14 is made of at least one conductive material selected from Al, Ag, Au, Cu, Pt, Cr, etc., or a transparent conductive material such as zinc oxide, ITO, tin dioxide, and Al, Ag, Au, Cu. , Pt, Cr, and the like, and has a function of collecting the photocurrent generated by the photoelectric conversion layer 12.

  The back electrode layer 14 is also formed on the entire surface of one side surface in the arrangement direction of the cells 10 (right side surface in FIG. 1) and is adjacent to the bottom of the separation groove 22 (adjacent to the right side in FIG. 1). Connected to the surface electrode layer 11 of the cell 10. That is, the back electrode layer 14 conformally covers one side surface in the arrangement direction of the cells 10.

  The laminated light reflecting film 15 is formed by a multilayer film in which a plurality of materials are laminated so as to cover the back electrode layer 14 and the side surfaces of the separation grooves 22 formed in the photoelectric conversion layer 12 and the back reflecting layer 13. The For example, the laminated light reflecting film 15 includes a thin film made of a first material having a refractive index lower than that of the photoelectric conversion layer 12, a thin film made of a second material having a higher refractive index than that of the first material, and a first material. The thin film is formed by alternately laminating a plurality of thin films having different refractive indexes. Thus, a high light confinement effect can be obtained by alternately laminating a material having a high refractive index and a material having a low refractive index.

FIG. 2 is a cross-sectional view schematically showing an enlarged part of the laminated light reflecting film. In this figure, a laminated light reflecting film 15 formed on the back electrode layer 14 and on the side surface of the separation groove 22 includes a silicon oxide (SiO _x (x = 1 to 2)) film 151, a silicon (Si) film 152, a nitride film. In this example, a silicon (SiN _x (x = 1 to 2)) film 153 is formed. Note that a silicon oxynitride (SiON _x (x = 1 to 2)) film may be used instead of the silicon nitride film 153. The typical film thickness of each of these films 151 to 153 is in the range of several to 100 nm. The laminated light reflecting film 15 having such a structure can improve the adhesion between the back electrode layer 14 and the sealing resin 18 in addition to the light confinement function, and can also be back electrode made of oxygen or water. Can prevent corrosion. The material used for the laminated light reflecting film 15 is not limited to silicon oxide, silicon nitride, or silicon oxynitride, and may be any material that satisfies the above refractive index conditions.

  FIG. 3 is a diagram illustrating a result of calculating the reflectance of the laminated light reflecting film using a general multiple reflection model of light. Here, when (a) only a 75 nm silicon oxide film is used as the laminated light reflecting film 15, (b) when a 75 nm silicon oxide film, a 25 nm silicon film, and a 75 nm silicon oxide film are laminated, And (c) The reflectivity when three layers of a 75 nm silicon oxide film, a 50 nm silicon film, and a 75 nm silicon oxide film are stacked is shown.

  As shown in this figure, in the case of the silicon oxide film (a), the maximum reflectance is near 55% near 450 nm, the reflectance decreases as the wavelength increases, and the reflectance is 700 nm. About 10%. On the other hand, in the case of the laminated film (b), the reflectance is about 30% at 400 nm, the reflectance is 0 near 470 nm, the maximum reflectance is near 62% near 560 nm, and the wavelength is The reflectance decreases as the length increases, but the reflectance is about 55% near 630 nm, the reflectance at 700 nm is about 38%, and the reflectance at 800 nm is about 18%. In the case of the laminated film (c), the reflectivity is about 10% at 400 nm, the maximum reflectivity is 65% near 500 nm, and the reflectivity decreases as the wavelength increases. The reflectivity is almost the same as that of the silicon oxide film (a).

  Thus, it can be seen that high reflectivity and wavelength selectivity can be obtained by laminating. Moreover, since the selectivity of this wavelength can be changed by changing the film thickness like the laminated film of (b) and the laminated film of (c), the wavelength that is difficult to be absorbed by the applied photoelectric conversion layer 12 The photovoltaic device 1 having high conversion efficiency can be manufactured by designing the laminated light reflecting film 15 having a reflectance suitable for the above.

FIG. 4 is a diagram showing the absorption coefficient of amorphous silicon, and FIG. 5 is a diagram showing the quantum efficiency of the amorphous silicon solar cell obtained by simulation. In FIG. 4, the horizontal axis indicates the wavelength (nm), and the vertical axis indicates the absorption coefficient (cm ⁻¹ ). In FIG. 5, the horizontal axis indicates the wavelength (nm) and the vertical axis indicates the quantum efficiency. FIG. 4 shows "Optical and Electrical Properties of Undoped Microcrystalline Silicon Deposited by the VHF-GD with Different Dilutions of Silane in Hydrogen" (Beck N., Torres P., Fric J., Remes Z., Poruba A., Stuchlikova HA, Fejfar A., Wyrsch N., Vanecek M., Kocka J., Shah A., MRS Symp., Vol. 452, 1997, p.761-766).

As shown in FIG. 4, in the amorphous silicon, the quantum efficiency of the photovoltaic device is less than 0.3 for light having a wavelength longer than the wavelength (about 630 nm) at which the absorption coefficient is 10,000 cm ^−1. , You can see that it is not available effectively. Therefore, by installing the laminated light reflecting film 15 having a high reflectance with respect to light having a wavelength of absorption coefficient of 10,000 cm ⁻¹ or less, light that has not been effectively used in the conventional structure can be regenerated. It can be returned to the power device and used. The same applies to other materials, and the wavelength range of reflected light can be changed by designing the film thickness and constituent materials of the laminated light reflecting film 15 in accordance with the material of the photoelectric conversion layer 12.

Further, from FIG. 5, if the wavelength is 720 nm or less, the quantum efficiency is increased to some extent, so that light can be converted into electricity. The absorption coefficient of amorphous silicon at 720 nm is 100 cm ⁻¹ from FIG.

As described above, when amorphous silicon is used as the photoelectric conversion layer 12, it is sufficient that the reflectance is in a certain range within a wavelength range of 630 to 720 nm (that is, an absorption coefficient of 10,000 to 100 cm ⁻¹ ). For example, in the case of the laminated light reflecting film 15 shown in FIG. 3, the laminated film (b) having a reflectance of about 55% at a wavelength of 630 nm and a reflectance of about 18% at a wavelength of 800 nm is laminated. More desirable as the light reflecting film 15.

In addition, the above description is a case where amorphous silicon is used as the photoelectric conversion layer 12, and the value varies depending on the material used for the photoelectric conversion layer 12. Therefore, the wavelength range in which the reflectance is increased depending on the material used for the photoelectric conversion layer 12. Must be obtained by experiments in advance. For example, when microcrystalline silicon is used as the photoelectric conversion layer 12, light in a longer wavelength region, that is, light up to approximately 1 μm can be converted. The absorption coefficient of the microcrystalline silicon at a wavelength of 1 μm is about 100 cm ⁻¹ . Therefore, in the case of microcrystalline silicon, the laminated light reflecting film 15 having a certain degree of reflectance may be used in the range where the absorption coefficient is 10,000 to 100 cm ⁻¹ (that is, the wavelength is 630 nm to ¹ μm).

Note that the higher the reflectance in the above description, the better. The spectra of the laminated films (b) and (c) in FIG. 3 are not necessarily optimal. For example, as in the laminated films (b) and (c), at least 630 nm (absorption coefficient is 10,000 cm ^−1). ) And the reflectance is desirably 20% or more. Further, it is desirable that the reflectance is 30% or more in the entire wavelength range of 630 to 720 nm as in the laminated film (b), and it is more desirable that the reflectance is 50% or more within the range.

As described above, the laminated light reflecting film 15 has a reflection coefficient of at least 20% or more in the wavelength range in which the absorption coefficient of the material constituting the photoelectric conversion layer 12 is 10,000 cm ⁻¹ or less and the quantum efficiency is greater than 0. Those with a rate are desirable.

  With the configuration as described above, the back electrode layer 14 of a certain cell 10 is connected to, for example, the surface electrode layer 11 of the cell 10 adjacent to the right in the separation groove 22, and the surface electrode layer 11 of a certain cell 10 is adjacent to the left The photovoltaic device 1 in which a plurality of cells 10 are connected in series is formed by being connected to the back electrode layer 14 of the other cell 10 in the separation groove 22 and repeating this.

  Here, an outline of the operation of the photovoltaic device 1 having such a structure will be described. When sunlight enters from the back surface of the insulating translucent substrate 2 (the surface on which the cell 10 is not formed), free carriers are generated in the photoelectric conversion layer 12 of each cell 10 and current is generated. The current generated in each cell 10 flows into the adjacent cell 10 via the front electrode layer 11 and the back electrode layer 14, and generates a generated current of the entire photovoltaic device 1 (module). Then, a generated current (photovoltaic force) is taken out of the photovoltaic device 1 through the external electrode 16 and the extraction wiring 17.

  Further, part of the light transmitted without being absorbed by the photoelectric conversion layer 12 is reflected by the back surface reflection layer 13 to the photoelectric conversion layer 12 side. Further, the light transmitted through the back surface reflection layer 13 is reflected to the photoelectric conversion layer 12 side by the laminated light reflection film 15. Furthermore, the light that has entered the photoelectric conversion layer 12 and reached the side surface of the separation groove 22 is also reflected by the laminated light reflection film 15 toward the photoelectric conversion layer 12. The light reflected by the back surface reflection layer 13 and the laminated light reflection film 15 enters the photoelectric conversion layer 12 again and becomes light that contributes to the generation of free carriers.

  Next, a method for manufacturing the photovoltaic device 1 having such a structure will be described. 6-1 to 6-6 are cross-sectional views schematically showing an example of the procedure of the method for manufacturing the photovoltaic device according to this embodiment.

  First, the surface electrode layer 11 made of a transparent conductive material containing zinc oxide, tin oxide, ITO or the like is formed on the insulating translucent substrate 2 by a film forming method such as sputtering, and photolithography technology, laser scribing, etc. By this method, the separation groove 21 is formed and separated at a predetermined position, and patterning is performed (FIG. 6-1).

  Subsequently, the photoelectric conversion layer 12 and the back surface reflection layer 13 are formed in order on the patterned surface electrode layer 11 (FIG. 6-2). Here, the photoelectric conversion layer 12 is made of a semiconductor thin film such as an amorphous silicon film having a pin-type three-layer structure, for example, and is formed by a film forming method such as a CVD (Chemical Vapor Deposition) method. Moreover, the back surface reflection layer 13 is made of a film having a high reflectivity from the visible light region to the near infrared region, such as Ag and Al, and is formed by a film forming method such as a sputtering method or a vapor deposition method.

  Thereafter, the separation groove 22 is formed at a predetermined position of the back surface reflection layer 13 and the photoelectric conversion layer 12 so as to be substantially parallel to the separation groove 21 formed between the front surface electrode layers 11 and not to overlap the position of the separation groove 21. It is processed into a line by a laser scribing method, a mechanical scribing method, an etching method, or the like (FIG. 6-3).

  Next, the back electrode layer 14 is formed so as to cover the back reflection layer 13 and the separation groove 22 (FIG. 6-4). A film forming method such as sputtering using a conductive material such as Ag or Al having high reflectivity and high electrical conductivity as the back electrode layer 14, or a laminated film of Ag and Al with a transparent conductive material such as tin oxide or ITO. Can be formed. At this time, the back electrode layer 14 is formed so as to conformally cover the separation groove 22.

  After that, for example, laser light is irradiated along the separation groove 22 from the back surface side of the insulating translucent substrate 2, and only a part of the back electrode layer 14 formed on the bottom and side surfaces of the separation groove 22 is the surface. Other portions are removed so as to be connected to the electrode layer 11 (FIGS. 6-5). Here, the back electrode layer 14 formed on the bottom surface portion and the right side surface portion of the separation groove 22 is removed. Thereby, the back electrode layer 14 between the adjacent cells 10 is electrically insulated.

  Next, a cover 31 such as a film is installed on the formation region of the external electrode connection portions of the cells 10 at both ends connected in series. Thereafter, the laminated light reflecting film 15 is formed on the back electrode layer 14 and the cover 31 partially separated by the separation groove 22 so as to conformally cover the side and bottom surfaces of the separation groove 22 (FIG. 6). -6). For example, when the laminated light reflecting film 15 is composed of a laminated film of silicon oxide and silicon, a material obtained by adding hydrogen and carbon dioxide to a silane-based gas such as monosilane or disilane by plasma CVD is used as a source gas. By forming the film, a laminated light reflecting film can be formed. At this time, a stacked film of silicon oxide and silicon can be formed by a simple operation such as switching on / off of the supply of carbon dioxide.

  Next, the cover 31 is removed, a resist, for example, is applied onto the laminated light reflecting film 15, and an opening is provided by photolithography so that the external electrode connection portion from which the cover 31 has been removed is opened. Thereafter, the external electrode 16 is formed of a metal material such as Ag or Al at the external electrode connection portion, and the resist is removed. Finally, an extraction wiring 17 is provided on the external electrode 16, and the cell 10 is sealed with a sealing resin 18, whereby the photovoltaic device 1 shown in FIG. 1 is obtained.

  In addition, in forming the external electrode connection portion, the method of covering the cover 31 before forming the laminated light reflecting film 15 is exemplified, but the present invention is not limited to this. For example, after the laminated light reflecting film 15 is formed, a resist is applied, and a resist mask having an opening at an external electrode formation position is formed by photolithography. Then, after etching the laminated light reflecting film 15 until the back electrode layer 14 is exposed using a resist mask, the external electrode 16 may be formed.

  Further, the multilayer structure of the laminated light reflecting film 15 described above is an example, and the layer configuration, the number of laminated layers, and the film thickness can be appropriately changed so as to have appropriate reflection characteristics.

  By the way, in the structure of the conventional photovoltaic device, the light which the light which injected into the photoelectric converting layer 12 leaked into the separation groove | channel 22 from the side surface was not able to be utilized effectively. However, by forming the laminated light reflecting film 15 that covers the side surface and the bottom surface of the separation groove 22 as in this embodiment, light leaking from the side surface of the photoelectric conversion layer 12 to the separation groove 22 is photoelectrically converted again. By returning to the layer 12, it can be used effectively, and the back electrode layer 14 can be protected at the same time.

  According to this embodiment, since the laminated light reflecting film 15 is formed in the separation groove 22 that separates the photoelectric conversion layers 12 between the cells 10, the side surface on which the separation grooves 22 are formed without being absorbed by the photoelectric conversion layer 12. The light that reaches has been returned to the cell 10 again. As a result, compared to the conventional structure in which the separation groove 22 does not have a reflecting structure, the leaked light can be used effectively, so that the photocurrent in the cell 10 increases and the conversion efficiency improves. Has the effect of In addition, the back electrode layer 14 can be protected by the laminated light reflecting film 15.

  As mentioned above, the photovoltaic device concerning this invention is useful for the solar cell comprised with a thin film.

DESCRIPTION OF SYMBOLS 1 Photovoltaic apparatus 2 Insulating translucent board | substrate 10 Cell 11 Front surface electrode layer 12 Photoelectric conversion layer 13 Back surface reflecting layer 14 Back surface electrode layer 15 Laminated light reflecting film 16 External electrode 17 Extraction wiring 18 Sealing resin 21 Separation groove 22 Separation groove 31 Cover 151 Silicon oxide film 152 Silicon film 153 Silicon nitride film

Claims (7)

A first electrode layer formed of a transparent conductive material on a light-transmitting substrate; a photoelectric conversion layer including a semiconductor material that converts light into electricity; and a second electrode layer formed of a conductive material. The second electrode layer of the cell is separated from the first electrode layer of the adjacent cell in a separation groove formed between the photoelectric conversion layer of the adjacent cell and the second electrode layer of the cell. In a photovoltaic device in which a plurality of the cells are connected in series,
A photovoltaic device comprising: a laminated light reflecting film in which two or more kinds of materials having different refractive indexes are laminated so as to cover at least a side surface and a bottom surface of the separation groove.   The photovoltaic device according to claim 1, wherein the laminated light reflecting film is also formed on the second electrode layer of the cell.   3. The photovoltaic according to claim 1, wherein the laminated light reflecting film has a material that selectively reflects light having a wavelength that is difficult to be absorbed by the photoelectric conversion layer, a film thickness, and the number of laminated layers. apparatus. The photoelectric conversion layer is composed of one or more semiconductor thin films each having a pin structure,
4. The laminated light reflecting film according to claim 1, wherein the photoelectric conversion layer has a reflectance of 20% or more in a wavelength region corresponding to 10,000 to 100 cm ^−1. A photovoltaic device according to claim 1.   The laminated light reflecting film is constituted by a multilayer film in which a plurality of low refractive index materials having a refractive index lower than that of the semiconductor material and a plurality of high refractive index materials having a refractive index higher than that of the low refractive index material are laminated. The photovoltaic device according to any one of claims 1 to 4. The low refractive index material is a dielectric film mainly composed of silicon oxide, silicon nitride or silicon oxynitride,
6. The photovoltaic device according to claim 5, wherein the high refractive index material is a semiconductor film mainly composed of Si having a refractive index higher than that of the dielectric film. A first step of forming a first electrode layer of each cell by forming a film made of a transparent conductive material on a light-transmitting substrate and patterning so as to separate each cell;
A second step of forming a photoelectric conversion layer containing a semiconductor material on the substrate on which the first electrode layer is formed;
A third step of forming a separation groove for separating the photoelectric conversion layer for each cell;
A fourth step of forming a second electrode layer by forming a conductive material layer on an upper surface of the photoelectric conversion layer and on a side surface and a bottom surface of the separation groove, and separating the conductive material layer between adjacent cells; When,
A fifth step of forming a laminated light reflecting film in which a plurality of materials configured to reflect light that is difficult to be absorbed by the semiconductor material is laminated so as to cover at least a bottom surface and a side surface of the separation groove;
A method for manufacturing a photovoltaic device, comprising:

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