JP2018174263A - Photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a decrease in conversion efficiency due to light deterioration when a silicon solar cell is installed on a window glass or the like. A photoelectric conversion device according to the present disclosure is a photoelectric conversion device including an amorphous silicon photoelectric conversion part and a microcrystalline silicon photoelectric conversion part at least in this order on a back surface side of a light-transmissive substrate and having a thickness of 400 nm. Of the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion part in the wavelength region of ˜750 nm and the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion part in the wavelength region of 400 nm to 750 nm, the smaller one is the larger one. The first value divided by the value of is included in the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion part in the wavelength region included in the sunlight spectrum of air mass 1.5 and the sunlight spectrum of air mass 1.5. Of the spectral sensitivity integrated current values of the microcrystalline silicon photoelectric conversion portion in the wavelength region, the smaller value is larger than the second value obtained by dividing the smaller value by the larger value. [Selection diagram] Figure 2

Description

  The present invention relates to a photoelectric conversion device.

  Patent Document 1 below discloses a window glass in which a solar cell is disposed inside a pair of glasses. Moreover, using an amorphous silicon solar cell as a solar cell arrange | positioned inside this pair glass is disclosed.

  The solar cell placed inside the pair glass is limited in the wavelength range in which light can be received by the transmittance of the pair glass, but is relatively high even in such a situation where the wavelength range in which light can be received is limited. Amorphous silicon solar cells that are easy to obtain conversion efficiency were suitable.

International Publication No. 2011/158568

  However, the conventional amorphous silicon solar cell has a large light deterioration, and it has been difficult to maintain high conversion efficiency in the long term. For this reason, there has been a problem in use for building-integrated photovoltaics (BIPV) applications, such as installation on window glass that is difficult to replace.

  The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to use a tandem solar cell having an amorphous silicon photoelectric conversion portion and a microcrystalline silicon photoelectric conversion portion that is less affected by light degradation as a window glass or the like. It is to obtain high conversion efficiency in the case where it is installed.

  (1) A photovoltaic device according to the present disclosure is a photoelectric conversion device including at least an amorphous silicon photoelectric conversion unit and a microcrystalline silicon photoelectric conversion unit in this order on the back surface side of a light-transmitting substrate, and has a wavelength of 400 nm. The smaller one of the spectral sensitivity integral current value of the amorphous silicon photoelectric conversion portion in the wavelength region of ˜750 nm and the spectral sensitivity integral current value of the microcrystalline silicon photoelectric conversion portion in the wavelength region of 400 nm to 750 nm. The first value divided by the value of is included in the spectral sensitivity integral current value of the amorphous silicon photoelectric conversion part in the wavelength region included in the solar spectrum of the air mass 1.5 and the solar spectrum of the air mass 1.5. A second value obtained by dividing the smaller value among the spectral sensitivity integrated current values of the microcrystalline silicon photoelectric conversion portion in the wavelength region by the larger value. Greater than the value.

  (2) In the photovoltaic device according to the above (1), the translucent substrate is disposed on the back side of the glass substrate, and the glass substrate has a transmittance in the ultraviolet region and the infrared region. Further, the configuration may be lower than the transmittance in the visible light region.

(3) In the photovoltaic device in the above (1) to (2), the photovoltaic device further includes a transparent conductive film provided between the translucent substrate and the amorphous silicon photoelectric conversion unit, it may be configured to include an SnO ₂ or ZnO.

  (4) In the photoelectric conversion device according to (1) to (3), the photoelectric conversion device further includes a back surface reflective electrode layer provided on a back surface side of the microcrystalline silicon photoelectric conversion unit, and the back surface reflective electrode layer includes Ag, Al, And any of these alloys may be used.

  (5) In the photoelectric conversion device in the above (4), the photoelectric conversion device further includes a transparent electrode layer provided between the microcrystalline silicon photoelectric conversion portion and the back surface reflective electrode layer, and the transparent electrode layer is made of ZnO or ITO. It is good also as a structure including.

  (6) In the photoelectric conversion device according to the above (1) to (5), the amorphous silicon photoelectric conversion part may have a film thickness that is 7% or less of the film thickness of the microcrystalline silicon photoelectric conversion part.

FIG. 1 is a plan view schematically showing a state in which the photoelectric conversion device according to this embodiment is installed on a glass substrate. FIG. 2 is a cross-sectional view schematically showing the photoelectric conversion device according to this embodiment. FIG. 3 is a spectral sensitivity characteristic diagram of the amorphous silicon photoelectric conversion unit and the microcrystalline silicon photoelectric conversion unit according to the present embodiment. FIG. 4 is a characteristic table of the photoelectric conversion devices of one example and a comparative example in the present embodiment under standard test conditions. FIG. 5 is a characteristic table under the ultraviolet light and infrared light cut of the photoelectric conversion devices of one example and a comparative example in this embodiment. FIG. 6 is a table showing spectral sensitivity integral current values and second values in a wavelength region included in the sunlight spectrum of the air mass 1.5 of the photoelectric conversion device of one example and a comparative example in the present embodiment. FIG. 7 is a table showing spectral sensitivity integral current values and first values in the wavelength region of 400 nm to 750 nm of the photoelectric conversion devices of one example and a comparative example in this embodiment.

  Embodiments of the present disclosure will be described below with reference to the drawings.

  FIG. 1 is a plan view schematically showing a state in which the photoelectric conversion device 100 according to the present embodiment is installed on the back side of a glass substrate 200 used for a window or the like.

  As shown in FIG. 1, the glass substrate 200 is provided so as to cover the light receiving surface sides of a plurality of photoelectric conversion devices 100 arranged at intervals. The plurality of photoelectric conversion devices 100 have, for example, a shape that extends in one direction, and each photoelectric conversion device 100 is disposed, for example, in an end region of the glass substrate 200. The photoelectric conversion device 100 is fixed to the glass substrate 200 with, for example, a sealing material.

  Here, the glass substrate 200 is a glass substrate used for a building window or the like, and is generally made of a material having high transmittance so that sunlight is incident on the room and the surface of the solar cell.

  However, in recent years, many types of glass base materials that cut infrared light and ultraviolet light contained in sunlight have been used, and the glass base material 200 according to the present embodiment is also capable of transmitting infrared light and ultraviolet light. Is a glass substrate 200 of a type that is significantly lower than the transmittance in the visible light region. As the glass substrate 200 in the present embodiment, the transmittance in the wavelength region of 90% or more in the wavelength region of 200 nm to 400 nm is lower than the minimum value of the transmittance in the visible light region, and in the wavelength region of 750 nm to 1400 nm. The transmittance of 95% or more in the wavelength region is lower than the minimum transmittance in the visible light region. That is, the glass substrate 200 in the present embodiment has a transmittance of 90% or more in the ultraviolet region and a transmittance of 95% or more in the infrared region in the wavelength region of 200 nm to 1400 nm. It is lower than the minimum value of transmittance in the visible light region.

  FIG. 2 is a cross-sectional view illustrating an outline of the photoelectric conversion device 100 according to the present embodiment.

  As illustrated in FIG. 2, the photoelectric conversion device 100 of the present disclosure includes a light-transmitting substrate 10, and the light-transmitting substrate 10 is disposed on the back side of the glass base material 200. The translucent substrate 10 is made of a material such as glass having a high transmittance.

A first transparent conductive film 20 is provided on the back side of the translucent substrate 10. For example, SnO ₂ or ZnO can be used as the first transparent conductive film 20. The first transparent conductive film 20 has a relatively high transmittance in the entire wavelength region, but absorbs an infrared light component and a part of the ultraviolet light component.

  An amorphous silicon photoelectric conversion unit 30 is provided on the back side of the first transparent conductive film 20. The amorphous silicon photoelectric conversion unit 30 includes a p-type amorphous silicon carbide layer 36 provided on the back side of the first transparent conductive film 20, and a non-doped i-type amorphous provided on the back side of the p-type amorphous silicon carbide layer 36. It has a silicon photoelectric conversion layer 34 and an n-type silicon layer 32 provided on the back side of the non-doped i-type amorphous silicon photoelectric conversion layer 34.

  The amorphous silicon photoelectric conversion unit 30 receives light transmitted from the glass substrate 200, the translucent substrate 10, and the first transparent conductive film 20 from the p-type amorphous silicon carbide layer 36 side, and is mainly non-doped i. In the type amorphous silicon photoelectric conversion layer 34, photoelectric conversion is performed. In the present embodiment, the p-type amorphous silicon carbide layer 36 is used as the p-type amorphous silicon layer disposed on the light receiving surface side of the non-doped i-type amorphous silicon photoelectric conversion layer 34. However, the present invention is not limited to this. Not.

  As described above, since the glass substrate 200 cuts ultraviolet light and infrared light, light of approximately 400 nm to 750 nm is incident on the amorphous silicon photoelectric conversion unit 30. Here, as shown in FIG. 3 showing the spectral sensitivity characteristics of the amorphous silicon photoelectric conversion unit 30 and the microcrystalline silicon photoelectric conversion unit 40, the amorphous silicon photoelectric conversion unit 30 has sensitivity in a wavelength range from 300 nm to around 700 nm. Thus, it can be seen that it is suitable as the photoelectric conversion device 100 attached to the glass substrate 200 that cuts such ultraviolet light and infrared light.

  On the other hand, the amorphous silicon photoelectric conversion unit 30 has a problem of causing light degradation.

  In the photoelectric conversion device 100 according to the present embodiment, a microcrystalline silicon photoelectric conversion unit 40 is provided on the back surface side of the amorphous silicon photoelectric conversion unit 30 to constitute a so-called tandem solar cell.

  The microcrystalline silicon photoelectric conversion unit 40 includes a p-type microcrystalline silicon layer 46 provided on the back side of the amorphous silicon photoelectric conversion unit 30 and an i-type microcrystal provided on the back side of the p-type microcrystalline silicon layer 46. It has a silicon photoelectric conversion layer 44 and an n-type microcrystalline silicon layer 42 provided on the back side of the i-type microcrystalline silicon photoelectric conversion layer 44.

  The microcrystalline silicon photoelectric conversion unit 40 receives light transmitted to the amorphous silicon photoelectric conversion unit 30 from the p-type microcrystalline silicon layer 46 side. Conversion is performed.

  Here, as shown in FIG. 3, the microcrystalline silicon photoelectric conversion unit 40 has higher spectral sensitivity on the longer wavelength side than the amorphous silicon photoelectric conversion unit 30, and has a wavelength range from about 500 nm to about 1000 nm. Has sensitivity. Therefore, the microcrystalline silicon photoelectric conversion unit 40 can efficiently absorb the long wavelength light that is not absorbed by the amorphous silicon photoelectric conversion unit 30 and contribute to power generation.

  In addition, unlike the amorphous silicon photoelectric conversion unit 30, the microcrystalline silicon photoelectric conversion unit 40 does not cause photodegradation. Therefore, the microcrystalline silicon photoelectric conversion unit 40 is configured to join the microcrystalline silicon photoelectric conversion unit 40 and the amorphous silicon photoelectric conversion unit 30. By doing so, the rate at which the conversion efficiency decreases due to light degradation can be reduced as compared with a photoelectric conversion device composed only of amorphous silicon solar cells.

  However, in the present disclosure, among the long-wavelength light that can be efficiently contributed to power generation by the microcrystalline silicon photoelectric conversion unit 40, infrared light is cut by the glass substrate 200 described above. Therefore, light having a wavelength longer than about 750 nm cannot be contributed to power generation, and the current value generated in the microcrystalline silicon photoelectric conversion unit 40 becomes small.

  When the current value generated in the microcrystalline silicon photoelectric conversion unit 40 becomes small, the current value generated in the amorphous silicon photoelectric conversion unit 30 connected in series to the microcrystalline silicon photoelectric conversion unit 40 becomes microcrystalline silicon. The current value generated in the photoelectric conversion unit 40 is limited, and as a result, the photoelectric conversion device 100 as a whole cannot expect high conversion efficiency.

  Therefore, in the present disclosure, of the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit 30 in the wavelength region of 400 nm to 750 nm and the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 in the wavelength region of 400 nm to 750 nm. The first value obtained by dividing the smaller value by the larger value is the spectral sensitivity integral current value of the amorphous silicon photoelectric conversion unit 30 in the wavelength region included in the solar spectrum of the air mass 1.5, and the air mass 1. 5 of the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 in the wavelength region included in the sunlight spectrum of 5 is larger than the second value obtained by dividing the smaller value by the larger value.

  The spectral sensitivity integrated current value means an output current density calculated by multiplying the spectral sensitivity by the sunlight spectrum intensity of the air mass 1.5 for each wavelength and integrating in a predetermined wavelength region.

  By adopting such a configuration, even in the photoelectric conversion device 100 attached to the glass substrate 200 from which ultraviolet light and infrared light are cut, the current value generated in the microcrystalline silicon photoelectric conversion unit 40 The current value generated in the amorphous silicon photoelectric conversion unit 30 can be suppressed from being significantly restricted, and the current generated in the microcrystalline silicon photoelectric conversion unit 40 by the current value generated in the amorphous silicon photoelectric conversion unit 30 can be suppressed. It can suppress that a value is restrict | limited remarkably. Furthermore, since the photoelectric conversion device 100 includes the microcrystalline silicon photoelectric conversion unit 40, it is possible to suppress a decrease in conversion efficiency due to light degradation, and it is possible to generate power in a wider wavelength range. Hereinafter, this configuration will be described in detail.

  First, of the current value generated in the amorphous silicon photoelectric conversion unit 30 and the current value generated in the microcrystalline silicon photoelectric conversion unit 40, the larger the value obtained by dividing the smaller value by the larger value, the greater the current matching. Indicates that is being done properly. And when light in a wavelength region of 400 nm to 750 nm is irradiated, the smaller one of the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit 30 and the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40. The first value obtained by dividing by the larger value indicates the degree of current matching in the photoelectric conversion device 100 in a state where the ultraviolet light and the infrared light are cut as in the present disclosure. By setting the first value to a value larger than the second value indicating the degree of current matching in the wavelength region included in the solar spectrum of the air mass 1.5, ultraviolet light and infrared light are used. Even in the photoelectric conversion device 100 attached to the glass substrate 200 having a cut, the current value generated in the amorphous silicon photoelectric conversion unit 30 is significantly limited by the current value generated in the microcrystalline silicon photoelectric conversion unit 40. It can be suppressed.

  FIG. 4 shows a standard test condition for the photoelectric conversion device of one example and a comparative example in the present embodiment (test condition where the solar radiation intensity is 1000 W / m2, the air mass is 1.5, and the temperature of the photoelectric conversion device is 25 ± 2 ° C.). It is the characteristic table below. The photoelectric conversion device 100 according to this embodiment includes an amorphous silicon photoelectric conversion unit 30 as a top cell and a microcrystalline silicon photoelectric conversion unit 40 as a bottom cell. In FIG. 4, the conversion efficiency and short circuit current density (Jsc) of the photoelectric conversion device 100 of one example in the present embodiment is 1, and the conversion efficiency and short circuit current density of the photoelectric conversion devices of Comparative Examples 1 to 3 are The values are shown as relative values with respect to the conversion efficiency and the short-circuit current density in one example. In one example of the present embodiment, as shown in FIG. 4, the amorphous silicon photoelectric conversion unit 30 has a film thickness of 130 nm, and the microcrystalline silicon photoelectric conversion unit 40 has a film thickness of 2300 nm. The film thickness of the conversion unit 30 is approximately 5.7% of the film thickness of the microcrystalline silicon photoelectric conversion unit 40.

  FIG. 6 is a table showing the spectral sensitivity integral current value and the second value in the wavelength region included in the solar spectrum of the air mass 1.5 of the photoelectric conversion devices of one example and a comparative example in the present embodiment. . In FIG. 6, the spectral sensitivity integrated current value of the top cell in the wavelength region included in the solar spectrum of the air mass 1.5 of the photoelectric conversion device 100 of one example in this embodiment is set to 1, and Comparative Examples 1 to 3 is a relative value of the spectral sensitivity integrated current value of the top cell in the wavelength region included in the sunlight spectrum of the air mass 1.5 of the photoelectric conversion device 3 with respect to the spectral sensitivity integrated current value of the top cell of the photoelectric conversion device 100 of one embodiment. Is displayed. In addition, the spectral sensitivity integrated current value of the bottom cell in the wavelength region included in the sunlight spectrum of the air mass 1.5 of the photoelectric conversion device 100 of the example and the photoelectric conversion devices of Comparative Examples 1 to 3 is converted into the photoelectric conversion of the example. It is displayed as a relative value to the spectral sensitivity integrated current value of the top cell of the apparatus 100.

  Moreover, in FIG. 6, in the photoelectric conversion apparatus 100 of one Example and the photoelectric conversion apparatus of Comparative Examples 2 and 3, the spectral sensitivity integral current value of the top cell in the wavelength region included in the solar spectrum of the air mass 1.5 and The second value obtained by dividing the smaller value among the spectral sensitivity integrated current values of the bottom cell by the larger value is displayed. Note that the photoelectric conversion device of Comparative Example 1 does not have the second value because it includes only the amorphous silicon photoelectric conversion unit.

  In the configuration of an example in the present embodiment, the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 that is the bottom cell is larger than the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit 30 that is the top cell. ing. Therefore, 1 which is the relative value of the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit 30 which is the top cell is 1.58 which is the relative value of the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 which is the bottom cell. 0.63, which is a value divided by, indicates the degree of current matching in the wavelength region included in the solar spectrum of the air mass 1.5, and this is the second value described above.

  As Comparative Example 1 shown in FIG. 4, a photoelectric conversion device composed of only amorphous silicon solar cells is used, and has a film thickness of 270 nm. Under standard test conditions, the relative value of the conversion efficiency of Comparative Example 1 is 0.93, which is slightly lower than the above-described example, and the relative value of the short-circuit current density is 1.57. Moreover, as shown in FIG. 6, the relative value of the spectral sensitivity integral current value in the wavelength region included in the solar spectrum of the air mass 1.5 is 1.57.

  As Comparative Example 2 shown in FIG. 4, similarly to the photoelectric conversion device 100 as an example in the present embodiment, a tandem having an amorphous silicon photoelectric conversion unit as a top cell and a microcrystalline silicon photoelectric conversion unit as a bottom cell. Type solar cells are used. The film thickness of the amorphous silicon photoelectric conversion portion is set to 230 nm, which is thicker than one example in the present embodiment described above. Further, the film thickness of the microcrystalline silicon photoelectric conversion portion is 2300 nm, which is the same film thickness as that of one example in this embodiment. Under standard test conditions, the relative value of the conversion efficiency of Comparative Example 2 is 1.25, which is higher than that of one example of the present embodiment, and the relative value of the short circuit current density is 1.31.

  Here, as shown in FIG. 6, in the photoelectric conversion device of Comparative Example 2, the relative value of the spectral sensitivity integrated current value of the top cell in the wavelength region included in the solar spectrum of the air mass 1.5 is 1.30. Thus, the value is higher than the relative value of the spectral sensitivity integral current value of one example in this embodiment. This is because the film thickness of the amorphous silicon photoelectric conversion part is thicker than that of one embodiment. On the other hand, the relative value of the spectral sensitivity integrated current value of the bottom cell in the wavelength region included in the solar spectrum of the air mass 1.5 is 1.32, which is a lower value than one example in the present embodiment. . This is because the film thickness of the amorphous silicon photoelectric conversion part is thicker than that of one embodiment, so that the light transmitted to the amorphous silicon photoelectric conversion part decreases and the light incident on the microcrystalline silicon photoelectric conversion part decreases. It is because it is doing.

  In Comparative Example 2, the second value obtained by dividing 1.30 which is the relative value of the spectral sensitivity integrated current value of the top cell by 1.32 which is the relative value of the spectral sensitivity integrated current value of the bottom cell is 0.99. Therefore, the value is higher than that of one example in the present embodiment. That is, the comparative example 2 has a higher current matching degree in the wavelength region included in the solar spectrum of the air mass 1.5 than the one in the present embodiment, and the spectral characteristics of the microcrystalline silicon photoelectric conversion unit. The integral value of the sensitivity and the integral value of the spectral sensitivity of the amorphous silicon photoelectric conversion unit are very close to each other.

  As a comparative example 3 shown in FIG. 4, a tandem having an amorphous silicon photoelectric conversion unit as a top cell and a microcrystalline silicon photoelectric conversion unit as a bottom cell, like the photoelectric conversion device 100 as an example in the present embodiment. Type solar cells are used. The film thickness of the amorphous silicon photoelectric conversion portion is set to 180 nm, which is thicker than one example in the present embodiment described above. Further, the film thickness of the microcrystalline silicon photoelectric conversion portion 40 is 2300 nm, which is the same film thickness as that of one embodiment. Under standard test conditions, the relative value of the conversion efficiency of Comparative Example 3 is 1.17, which is higher than that of one example of the present embodiment, and the relative value of the short circuit current density is 1.18.

  Here, as shown in FIG. 6, in the photoelectric conversion device of Comparative Example 3, the relative value of the spectral sensitivity integrated current value of the top cell in the wavelength region included in the solar spectrum of the air mass 1.5 is 1.18. Thus, the value is higher than the relative value of the spectral sensitivity integral current value of one example in this embodiment. This is because the film thickness of the amorphous silicon photoelectric conversion part is thicker than that of one embodiment. On the other hand, the relative value of the spectral sensitivity integrated current value of the bottom cell in the wavelength region included in the solar spectrum of the air mass 1.5 is 1.48, which is a lower value than one example in the present embodiment. . This is because the film thickness of the amorphous silicon photoelectric conversion part is thicker than that of one embodiment, so that the light transmitted to the amorphous silicon photoelectric conversion part decreases and the light incident on the microcrystalline silicon photoelectric conversion part decreases. It is because it is doing.

  In Comparative Example 3, the second value obtained by dividing 1.18 which is the relative value of the spectral sensitivity integrated current value of the top cell by 1.48 which is the relative value of the spectral sensitivity integrated current value of the bottom cell is 0.79. Thus, the value is higher than that of one example in the present embodiment and lower than that of Comparative Example 2. That is, the comparative example 3 has a higher current matching degree than the one example in the present embodiment and a lower current matching degree than the comparative example 2 in the wavelength region included in the solar spectrum of the air mass 1.5. ing.

  FIG. 5 is a characteristic table under the ultraviolet light and infrared light cut of the photoelectric conversion device of one example and a comparative example in the present embodiment, and each photoelectric conversion device 100 is installed in the ultraviolet light and infrared light cut glass. The relative value of the simulation value at is displayed. In FIG. 5, the conversion efficiency and the short-circuit current density (Jsc) under the standard test conditions of the photoelectric conversion device 100 of the embodiment shown in FIG. Conversion values under the standard test conditions of the photoelectric conversion device 100 of one embodiment are converted into simulation values of conversion efficiency and short-circuit current density in the state where the photoelectric conversion devices of Comparative Examples 1 to 3 are installed in the ultraviolet light and infrared light cut glass. It is displayed as a relative value to the efficiency and the short-circuit current density.

  As shown in FIG. 5, the relative value of the conversion efficiency in the state installed in the ultraviolet light and infrared light cut glass of the photoelectric conversion device 100 of one embodiment is 0.50, and the relative value of the short circuit current density is 0.51. It has become. Under the installation of ultraviolet light and infrared light cut glass, light in each wavelength region is absorbed or reflected, and the amount of light incident on the photoelectric conversion device 100 is reduced. In particular, the ultraviolet light region and the infrared light region are reduced. There is almost no incident light. Therefore, it is estimated that the short circuit current density is greatly reduced, and the conversion efficiency is lowered accordingly.

  FIG. 7 is a table showing spectral sensitivity integrated current values and first values in the wavelength region of 400 to 750 nm of the photoelectric conversion devices of one example and a comparative example in the present embodiment. In FIG. 7, the spectral sensitivity integrated current value of the top cell in the wavelength region included in the solar spectrum of the air mass 1.5 of the photoelectric conversion device 100 of one example in the present embodiment is 1, and 400 to 750 nm. In the wavelength range, the spectral sensitivity integrated current value and the bottom cell spectral sensitivity integrated current value of the photoelectric conversion device 100 of one embodiment and the photoelectric conversion devices of Comparative Examples 1 to 3 are included in the solar spectrum of the air mass 1.5. In the wavelength region, the photoelectric conversion device 100 of one embodiment of the present invention is displayed as a relative value to the spectral sensitivity integrated current value of the top cell.

  In FIG. 7, the spectral sensitivity integrated current value of the top cell and the spectral sensitivity integrated current of the bottom cell in the wavelength region of 400 to 750 nm in the photoelectric conversion device 100 of one example and the photoelectric conversion devices of Comparative Examples 2 and 3. The first value obtained by dividing the smaller value by the larger value among the values is displayed. In addition, since the photoelectric conversion apparatus of the comparative example 1 has only an amorphous silicon photoelectric conversion part, it does not have a 1st value.

  In the configuration of an example in this embodiment, the relative value of the spectral sensitivity integral current value of the amorphous silicon photoelectric conversion unit 30 that is the top cell is 0.93 in the wavelength range of 400 to 750 nm, and the air mass It can be seen that there is a slight decrease from the relative value of the spectral sensitivity integral current value of the amorphous silicon photoelectric conversion unit 30 in the wavelength region included in the 1.5 sunlight spectrum.

  On the other hand, in the wavelength range from 400 to 750 nm, the relative value of the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 that is the bottom cell is 0.99, and is included in the solar spectrum of the air mass 1.5. It can be seen that the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 in the wavelength region is significantly reduced from 1.58 which is a relative value. As shown in the spectral sensitivity characteristics of microcrystalline silicon in FIG. 3, the microcrystalline silicon photoelectric conversion unit 40 has a higher spectral sensitivity on the longer wavelength side than the amorphous silicon photoelectric conversion unit 30, and is approximately 500 nm. This is because light in the wavelength range from 750 nm to 1000 nm is excluded from the integral range of spectral sensitivity.

  In the photoelectric conversion apparatus 100 shown in an example of this embodiment, the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 that is the bottom cell is amorphous that is the top cell even in the wavelength range from 400 to 750 nm. It is slightly larger than the spectral sensitivity integral current value of the silicon photoelectric conversion unit 30. Therefore, 0.93 which is the relative value of the spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit 30 which is the top cell is 0, which is the relative value of the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit 40 which is the bottom cell. 0.94 which is a value divided by .99 indicates the current matching degree in the wavelength region of 400 nm to 750 nm, which is the first value described above.

  Thus, in one example of the present embodiment, the second value indicating the degree of current matching in the wavelength region included in the solar spectrum of the air mass 1.5 was 0.63, whereas 400 nm to The first value indicating the current matching degree in the wavelength region of 750 nm is a high value of 0.94. In addition, as shown in FIG. 5, the relative value of the conversion efficiency of the photoelectric conversion device 100 of one example in the present embodiment is 0.50 under the installation of ultraviolet light and infrared light cut glass. Is a value higher than the relative value of any conversion efficiency of Comparative Examples 1 to 3 under the setting of ultraviolet light and infrared light cut glass.

  This is because the current value generated in the microcrystalline silicon photoelectric conversion unit 40 is expected to decrease under the setting of ultraviolet light and infrared light cut glass, and the amorphous silicon photoelectric conversion unit 30 is intentionally used under standard test conditions. By keeping the current value generated and the current value generated in the microcrystalline silicon photoelectric conversion unit 40 unbalanced, it is possible to obtain a relatively high conversion efficiency even under the installation of ultraviolet light and infrared light cut glass. Indicates that it has been done.

  As for Comparative Examples 2 and 3, in the wavelength region from 400 to 750 nm, the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric conversion unit that is the bottom cell is significantly reduced, and the spectrum of the amorphous silicon photoelectric conversion unit that is the top cell is reduced. It is smaller than the sensitivity seat current value. Therefore, the value obtained by dividing the spectral sensitivity integrated current value of the bottom cell, which is the smaller value, by the spectral sensitivity integrated current value of the top cell, which is the larger value, is the current matching degree in the wavelength region from 400 to 750 nm. The first values are 0.57 in Comparative Example 2 and 0.77 in Comparative Example 3, respectively.

  In Comparative Examples 2 and 3, the second value indicating the current matching degree in the wavelength region included in the solar spectrum of the air mass 1.5 was higher than that of one example of the present embodiment, but this 400 to 750 nm. The first value indicating the current matching degree in the wavelength region up to is lower than that of one example of the present embodiment.

  As a result, in the wavelength region included in the solar spectrum of the air mass 1.5, the current value generated in the microcrystalline silicon photoelectric conversion unit that is well matched to the current value generated in the amorphous silicon photoelectric conversion unit is In the wavelength range of 400 to 750 nm, the current value generated in the amorphous silicon photoelectric conversion part is limited as a result of a significant decrease. In addition, in FIG. 5, the relative value of the conversion efficiency in the state attached to the glass substrate 200 that cuts ultraviolet light and infrared light so as to support this is 0.34 in Comparative Example 2 and Comparative Example 3 0.42, which is lower than the relative value of the conversion efficiency of one example of this embodiment, and further smaller than the relative value of 0.49 of the conversion efficiency of Comparative Example 1 consisting only of an amorphous silicon photoelectric conversion unit. It is a value.

  On the other hand, in the photoelectric conversion device 100 of one example of this embodiment, the film thickness of the amorphous silicon photoelectric conversion unit 30 is set to 5.7% of the film thickness of the microcrystalline silicon photoelectric conversion unit 40, and a comparative example. By forming a thin film as compared with 1 to 3 and setting a large amount of light that can be absorbed by the microcrystalline silicon photoelectric conversion unit 40, a high current can be obtained even when ultraviolet light and infrared light cut glass are installed. The degree of matching can be realized, and conversion efficiency higher than those of Comparative Examples 1 to 3 can be obtained. The film thickness of the amorphous silicon photoelectric conversion section 30 is preferably 7% or less of the film thickness of the microcrystalline silicon photoelectric conversion section 40, and further, 5.7% as shown in one example of this embodiment. The following is desirable.

  In the present embodiment, the second transparent conductive film 52 and the back reflective electrode layer 50 are provided on the back side of the microcrystalline silicon photoelectric conversion unit 40.

  As a constituent material of the second transparent conductive film 52, for example, ZnO, ITO, or the like can be used.

  As a constituent material of the back surface reflective electrode layer 50, for example, Ag or Al can be used. The back surface reflective electrode layer 50 reflects the light transmitted to the amorphous silicon photoelectric conversion unit 30 and the microcrystalline silicon photoelectric conversion unit 40 again to the microcrystalline silicon photoelectric conversion unit 40 and the amorphous silicon photoelectric conversion unit 30 side, The microcrystalline silicon photoelectric conversion portion 40 and the amorphous silicon photoelectric conversion portion 30 side serve to absorb this reflected light.

[Method for Manufacturing Photoelectric Conversion Device 100]
Hereinafter, the manufacturing method of the photoelectric conversion apparatus 100 according to the present embodiment will be described.

[Transparent substrate 10 preparation step]
First, as shown in FIG. 2, a translucent substrate 10 is prepared. As the translucent board | substrate 10, the plate-shaped member and sheet-like member which consist of glass, transparent resin, etc. are used, for example.

[Step of forming first transparent conductive film 20]
Next, as shown in FIG. 2, a first transparent conductive film 20 made of a conductive metal oxide or the like is formed on the back surface side of the translucent substrate 10. Specific examples of the conductive metal oxide include SnO ₂ and ZnO. The first transparent conductive film 20 can be formed on the rear surface side of the translucent substrate 10 by a method such as CVD (Chemical Vapor Deposition), sputtering, or vapor deposition. The first transparent conductive film 20 desirably has an effect of increasing the scattering of incident light on the surface thereof. Specifically, it is desirable that the first transparent conductive film 20 has an effect of increasing the scattering of incident light by having fine irregularities on the surface.

[Step of forming amorphous silicon photoelectric conversion unit 30]
Next, as shown in FIG. 2, an amorphous silicon photoelectric conversion unit 30 is formed on the back side of the first transparent conductive film 20. The amorphous silicon photoelectric conversion unit 30 includes a p-type amorphous silicon carbide layer 36, a non-doped i-type amorphous silicon photoelectric conversion layer 34, and an n-type silicon layer 32. The amorphous silicon photoelectric conversion unit 30 can be formed by, for example, a high frequency plasma CVD method.

  Note that a low refractive index layer such as a silicon oxide layer containing microcrystalline silicon may be provided on the back side of the non-doped i-type amorphous silicon photoelectric conversion layer 34 instead of the n-type silicon layer 32. By providing the low refractive index layer, the light that has not been absorbed by the non-doped i-type amorphous silicon photoelectric conversion layer 34 and has passed through to the back surface side is reflected again to the non-doped i-type amorphous silicon photoelectric conversion layer 34 side, and non-doped i-type It can be absorbed in the amorphous silicon photoelectric conversion layer 34.

As conditions for using the high-frequency plasma CVD method as a method for forming the amorphous silicon photoelectric conversion portion 30, in this embodiment, the substrate temperature is 100 to 300 ° C., the pressure is 30 to 1500 Pa, and the high-frequency power density is 0. 01-0.5 W / cm2. As a raw material gas to be used, a silicon-containing gas such as SiH ₄ or Si ₂ H ₆ or a mixture of these gases and H ₂ is used. B ₂ H ₆ or the like is preferably used as a dopant gas for forming the p-type amorphous silicon carbide layer 36. As a dopant gas for forming the n-type silicon layer 32, PH ₃ or the like is preferably used.

  In this embodiment, the film thickness of the amorphous silicon photoelectric conversion unit 30 is made thinner than the film thickness of the microcrystalline silicon photoelectric conversion unit 40 and can be absorbed by the microcrystalline silicon photoelectric conversion unit 40. By setting a large amount of light, high current matching can be realized and relatively high conversion efficiency can be obtained even when ultraviolet light or infrared light cut glass is installed.

[Step of forming microcrystalline silicon photoelectric conversion section 40]
Next, as shown in FIG. 2, a microcrystalline silicon photoelectric conversion unit 40 is formed on the back side of the amorphous silicon photoelectric conversion unit 30. The microcrystalline silicon photoelectric conversion portion 40 is formed including a p-type microcrystalline silicon layer 46, an i-type microcrystalline silicon photoelectric conversion layer 44, and an n-type microcrystalline silicon layer 42. The microcrystalline silicon photoelectric conversion unit 40 can be formed by, for example, a high-frequency plasma CVD method.

  Note that a low refractive index layer such as a silicon oxide layer containing microcrystalline silicon may be interposed between the i-type microcrystalline silicon photoelectric conversion layer 44 and the n-type microcrystalline silicon layer 42. By providing the low refractive index layer, the long wavelength light that has not been absorbed by the i-type microcrystalline silicon photoelectric conversion layer 44 and has passed through to the back surface side is reflected again to the i-type microcrystalline silicon photoelectric conversion layer 44 side. It can be absorbed in the type microcrystalline silicon photoelectric conversion layer 44.

As a condition for using the high-frequency plasma CVD method as a method for forming the microcrystalline silicon photoelectric conversion portion 40, the substrate temperature is set to 100 to 300 ° C. in the present embodiment, similarly to the amorphous silicon photoelectric conversion portion 30 described above. The pressure is 30 to 1500 Pa and the high frequency power density is 0.01 to 0.5 W / cm ² . As a raw material gas to be used, a silicon-containing gas such as SiH ₄ or Si ₂ H ₆ or a mixture of these gases and H ₂ is used. As a dopant gas for forming the p-type microcrystalline silicon layer 46, B ₂ H ₆ or the like is preferably used. As a dopant gas for forming the n-type microcrystalline silicon layer 42, PH ₃ or the like is preferably used.

[Step of forming second transparent conductive film 52]
Next, as shown in FIG. 2, a second transparent conductive film 52 is formed on the back side of the microcrystalline silicon photoelectric conversion unit 40. As a material constituting the second transparent conductive film 52, for example, ZnO, ITO, or the like can be used. As a method for forming the second transparent conductive film 52, for example, sputtering, vapor deposition, or the like can be used.

[Backside reflective electrode layer 50 forming step]
Next, as shown in FIG. 2, a back surface reflective electrode layer 50 is formed on the back surface side of the second transparent conductive film 52. As a material constituting the back surface reflective electrode layer 50, for example, Ag, Al, or an alloy thereof can be used. As a method of forming the back surface reflective electrode layer 50, for example, sputtering, vapor deposition, or the like can be used.

DESCRIPTION OF SYMBOLS 10 Translucent substrate, 20 1st transparent conductive film, 30 Amorphous silicon photoelectric conversion part, 32 n-type silicon layer, 34 Non-doped i-type amorphous silicon photoelectric conversion layer, 36 p-type amorphous silicon carbide layer, 40 Microcrystalline silicon photoelectric Conversion unit, 42 n-type microcrystalline silicon layer, 44 i-type microcrystalline silicon photoelectric conversion layer, 46 p-type microcrystalline silicon layer, 50 back reflective electrode layer, 52 second transparent conductive film, 100 photoelectric conversion device, 200 glass Base material.

Claims (6)

On the back side of the translucent substrate, a photoelectric conversion device including at least an amorphous silicon photoelectric conversion unit and a microcrystalline silicon photoelectric conversion unit in this order,
The smaller one of the spectral sensitivity integrated current value of the amorphous silicon photoelectric converter in the wavelength region of 400 nm to 750 nm and the spectral sensitivity integrated current value of the microcrystalline silicon photoelectric converter in the wavelength region of 400 nm to 750 nm is increased. The first value divided by the value of
The spectral sensitivity integrated current value of the amorphous silicon photoelectric conversion unit in the wavelength region included in the solar spectrum of the air mass 1.5, and the microcrystalline silicon photoelectric conversion unit in the wavelength region included in the solar spectrum of the air mass 1.5. Of the spectral sensitivity integral current value, larger than the second value obtained by dividing the smaller value by the larger value,
Photoelectric conversion device. The translucent substrate is disposed on the back side of the glass substrate,
The glass substrate has a lower transmittance in the ultraviolet region and in the infrared region than in the visible region.
The photoelectric conversion device according to claim 1. A transparent conductive film provided between the translucent substrate and the amorphous silicon photoelectric conversion unit;
The transparent conductive film includes SnO ₂ or ZnO.
The photoelectric conversion device according to claim 1. Further comprising a back surface reflective electrode layer provided on the back surface side of the microcrystalline silicon photoelectric conversion part,
The back reflective electrode layer includes any one of Ag, Al, and alloys thereof.
The photoelectric conversion apparatus as described in any one of Claims 1 thru | or 3. Further comprising a transparent electrode layer provided between the microcrystalline silicon photoelectric conversion portion and the back reflective electrode layer,
The transparent electrode layer includes ZnO or ITO.
The photoelectric conversion device according to claim 4. The film thickness of the amorphous silicon photoelectric conversion part is 7% or less of the film thickness of the microcrystalline silicon photoelectric conversion part.
The photoelectric conversion apparatus as described in any one of Claims 1 thru | or 5.

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