WO2017126683A1

WO2017126683A1 - Transmission type thin film solar cell

Info

Publication number: WO2017126683A1
Application number: PCT/JP2017/001996
Authority: WO
Inventors: 康之渡邊
Original assignee: 学校法人東京理科大学
Priority date: 2016-01-21
Filing date: 2017-01-20
Publication date: 2017-07-27
Also published as: JP7093988B2; JPWO2017126683A1

Abstract

A transmission type thin film solar cell (10) which comprises: a solar cell sheet (12) that transmits at least some of sunlight; a transmission type organic EL sheet (16); and a light control unit (14) that controls the transmission amount of the sunlight.

Description

Transmission type thin film solar cell

The present disclosure relates to a transmissive thin film solar cell.

A solar cell using sunlight as an energy source has attracted attention as a utilization of natural energy. As a technology for utilizing solar cells in the agricultural field, a technology that balances farming with solar power generation using solar cells (so-called solar sharing) is being studied.
As one mode of solar sharing, there is a method of installing a non-translucent solar cell (silicon-based solar cell panel) on farmland. At this time, it is preferable to increase the installation area of the solar cell panel in view of securing the amount of power generation. However, there is concern about adverse effects on agricultural products because the solar panels can shade the farmland. For this reason, at present, in order to suppress a decrease in crop yield, solar panels are installed with a certain amount of space secured. The installation area of solar panels necessary to secure the amount of sunshine suitable for the growth of agricultural crops is estimated to be about 30% of the entire farmland, and at present, farmland is used effectively enough for both power generation and agriculture. It is hard to say that it is.

As a technique for using conventional solar cells for farmland, for example, a solar cell panel is installed in a part of farmland, an auxiliary light source is driven by the electric power obtained by the solar cell panel, and it is cultivated in other parts of the farmland. There has been proposed a plant cultivation method in which a plant is irradiated with auxiliary light emitted from the auxiliary light source together with sunlight (see JP 2011-200163 A).

In addition, a greenhouse has been proposed in which auxiliary irradiation light is used in the absence of solar radiation. That is, a thin-film solar cell module that is substantially translucent in the first wavelength region, receives solar radiation, and converts solar radiation in a second wavelength region different from the first wavelength region into electrical energy. And a selective reflection layer disposed opposite the photoelectric layer so as to selectively reflect radiation in the second wavelength region transmitted by the photoelectric layer, and radiation in the second wavelength region. An additional photoelectric layer that absorbs light and converts it into electrical energy, a selective reflection layer is disposed between the photoelectric layer and the additional photoelectric layer, and a first wavelength region has a first wavelength of 350 to 500 nm The thin film solar cell module including a band and a second wavelength band of 600 to 700 nm and a second wavelength region including a wavelength range of 500 to 600 nm is disclosed (refer to Japanese Patent Application Publication No. 2014-522101). .

Also, a part of external light such as sunlight, specifically, a phosphor that absorbs light with a wavelength that has a small contribution to photosynthesis of plants and converts it into light with a wavelength that has a large contribution to photosynthesis, and radiation from the phosphor. There has been proposed a plant cultivation apparatus including a daylighting unit having a fluorescent light guide that guides a part of the emitted light and a solar cell element that receives the fluorescent light guide (International Publication WO2012 / 141091 pamphlet).

However, in the technique described in Japanese Patent Application Laid-Open No. 2011-200163, the farmland is shared between the installation of solar cells and the cultivation of crops. When pursued, the amount of sunlight necessary for the growth of agricultural products cannot be secured, and the function as farmland may be impaired.
On the other hand, in the technique described in Japanese Patent Publication No. 2014-522101, it is disclosed that a light-transmitting thin film solar cell module is used in a greenhouse and the wavelength of sunlight is divided into power generation and photosynthesis. In Japanese Patent Laid-Open No. 2014-522101, although a wavelength of 500 nm to 600 nm is selectively reflected and converted into electric energy, there is no proposal to convert it into light having a wavelength that contributes to photosynthesis.

An object of an embodiment of the present invention is a transmission that has a dimming function and a transmissive organic EL sheet, and can control the light environment under the solar cell to a desired state regardless of the intensity of sunlight. It is to provide a type thin film solar cell.

Means for solving the problems include the following embodiments.
<1> A transmissive thin-film solar cell having a solar cell sheet that transmits at least part of sunlight, a transmissive organic EL (electroluminescence) sheet, and a light control unit that adjusts the amount of transmitted sunlight.
<2> The transmissive thin-film solar cell according to <1>, including the solar cell sheet, the light control unit, and the transmissive organic EL sheet in this order from the sunlight incident side.
<3> The transmissive thin-film solar cell according to <1>, including the solar cell sheet, the transmissive organic EL sheet, and the light control unit in this order from the sunlight incident side.

<4> The transmissive thin film solar cell according to any one of <1> to <3>, wherein the solar cell sheet has selective light transmittance.
<5> The transmissive thin film solar cell according to <4>, wherein the selective light transmittance is a characteristic of transmitting light in a visible light region.
<6> The transmissive thin-film solar cell according to any one of <1> to <5>, wherein the solar cell sheet is an organic thin-film solar cell sheet.

<7> Any one of <1> to <6>, further including a wavelength conversion unit that converts a wavelength of light incident through the solar cell sheet on a side opposite to a sunlight incident side of the solar cell sheet 2. A transmission type thin film solar cell according to item 1.

<8> Further, a light amount measuring unit that measures the amount of transmitted light that has passed through the solar cell sheet is provided, and the transmission type is measured when the amount of transmitted light measured by the light amount measuring unit does not reach a predetermined amount. The transmission type thin film solar cell according to any one of <1> to <7>, in which energy is applied to the organic EL sheet to emit light.

According to one embodiment of the present invention, it is possible to provide a transmissive thin-film solar cell that has a dimming function and can maintain a desired light environment regardless of the amount of received sunlight.

It is a schematic sectional drawing which shows the structure of 1st Embodiment which is an example of the transmissive | pervious thin film solar cell of this indication. It is a schematic sectional drawing which shows the structure of 2nd Embodiment which is another example of the transmissive | pervious thin film solar cell of this indication. It is a schematic sectional drawing which shows 3rd Embodiment structure which is an example of the transmission type thin film solar cell of this indication which further has a wavelength conversion part. It is the schematic which shows the usage condition of the thin film solar cell 30, and the state of light in case the light quantity of sunlight in the daytime is large. It is the schematic which shows the usage condition and the state of light of the thin film solar cell 30 in case the light quantity of sunlight in the daytime is moderate. It is the schematic which shows the use aspect of the thin film solar cell 30, and the state of light in the case of controlling the transmitted light quantity of sunlight as needed in the daytime of the fine weather, morning or evening. It is the schematic which shows the usage condition and light state of the thin film solar cell 30 when sunlight is not irradiated at night. It is the schematic which shows the usage condition and light state of the thin film solar cell 30 when the light quantity of sunlight is comparatively small at the time of rainy weather or cloudy weather. 3 is a graph showing the spectral irradiance of transmitted light of the transmissive thin film solar cell 1 of Example 1. FIG. 4 is a graph showing current-voltage characteristics of the transmission-type thin film solar cell 1 of Example 1 measured under sunlight irradiation. It is a graph which shows the spectral irradiance of the transmitted light of the transmission type thin film solar cell 2 of Example 2 which has a wavelength conversion part.

Hereinafter, embodiments of the present invention will be described in detail.
In the present specification, a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.

The transmission-type thin film solar cell of the present disclosure (hereinafter, simply referred to as “thin film solar cell”) may be referred to as a solar cell sheet that transmits at least part of sunlight (hereinafter, simply referred to as “solar cell sheet”). ), A transmission type organic EL sheet (hereinafter, sometimes simply referred to as “organic EL sheet”), and a light control unit (hereinafter simply referred to as “light control unit”) that adjusts the amount of transmitted sunlight. Have). A thin film solar cell has a solar cell sheet, an organic EL sheet, and a light control part, and may have another member as needed.
In each embodiment of the thin-film solar cell described in this specification, “having members in this order” constituting the thin-film solar cell means having the members in the predetermined configuration order in each embodiment, It does not prevent having any other members.

Hereinafter, the configuration of the thin film solar cell will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing the layer configuration of the thin-film solar cell 10 of the first embodiment.
The thin film solar cell 10 of this embodiment has the solar cell sheet 12, the light control part 14, and the organic EL sheet 16 in this order from the sunlight receiving side. The sunlight receiving side is indicated by an arrow in FIG.
There is a region where the light environment is adjusted or controlled on the side opposite to the light receiving side of the thin-film solar cell 10 (hereinafter, the region where the light environment is adjusted or controlled may be referred to as a “light environment adjusting region”). 1, the region indicated by (A) on the side opposite to the light receiving side of the thin-film solar cell 10 is an example of the light environment adjustment region, although not illustrated, in FIGS. The region opposite to the light receiving side of the thin-film

solar cells

20 and 30 is an optical environment adjustment region similar to the region indicated by (A) in FIG.
Examples of the light environment adjustment area include a light-receiving side of a thin-film solar cell, such as a greenhouse that grows plants, a plant factory that uses sunlight, a poultry house, a livestock house that raises animals such as pigs, and a fish farm. Is the region on the opposite side.

Since the solar cell sheet 12 transmits at least part of sunlight, the light (transmitted light) transmitted through the solar cell sheet 12 reaches the light control unit 14. Further, the transmitted light passes through the light control unit 14 and reaches the organic EL sheet 16, and further passes through the organic EL sheet 16 and reaches the light environment adjustment region. The light control unit 14 adjusts the amount of transmitted light that reaches the light environment adjustment region.
For example, when the sunlight is too strong and the leafy vegetables have a light quantity that causes sunburn, the light control unit 14 can reduce the transmitted light of the sunlight to a desired light quantity.
At night, in cloudy weather, or when there is no need to reduce the amount of sunlight, the light control unit 14 does not adjust the amount of light and transmits the received light as it is.
As will be described later, when a chromic material is used for the light control unit 14, the light control unit 14 itself changes color according to the amount of received light and controls light transmission without using a sensor such as a light meter. can do. However, the light control part 14 is not limited to the aspect using a chromic material.

The organic EL sheet 16 emits light when given energy. When the amount of sunlight is small, energy is applied to the organic EL sheet 16 to emit light, and a necessary amount of light is supplied to plants and the like. The energy applied to the organic EL sheet 16 may be the power generated by the solar cell sheet 12 described above, or may be energy supplied as power from an external power source.

According to the thin film solar cell 10 of the first embodiment, when the amount of irradiated sunlight is large, power generation by the solar cell sheet 12 is efficiently performed, and the dimmer 14 transmits more sunlight than necessary. Therefore, the amount of light reaches the light environment adjustment region as designed. On the other hand, when the amount of irradiated sunlight is small, the light control unit 14 does not suppress the transmission of sunlight, and the organic EL sheet 16 emits light and emits light of a desired wavelength in the light environment adjustment region. It can be supplied with the required amount of light.
For this reason, when the thin film solar cell 10 of the present embodiment is applied together with a resin sheet such as a roof sheet or instead of a roof sheet in, for example, a greenhouse, an optical environment adjustment region is formed in the greenhouse, and it is related to the weather. First, the light environment is controlled to a predetermined condition, and a light quantity suitable for plant growth is supplied.

The thin-film solar cell 10 of the present embodiment may further include a light amount measuring unit (not shown) that measures the amount of transmitted light that is incident on the solar cell sheet 12 and transmitted through the solar cell sheet 12. As the light amount measuring means, an illuminometer used for measuring the light environment for photosynthesis of plants, a photon sensor having sensitivity in the photosynthesis effective wavelength region, or the like is preferably used. By having such light quantity measuring means, it is possible to design the organic EL sheet 16 to emit light when the quantity of transmitted light does not reach the amount necessary for plant growth, for example. The thin-film solar cell reflects the light amount measurement means, the determination means for comparing and determining the result measured by the light amount measurement means, and the energy application to the organic EL sheet according to the determination by the determination means. By providing the means and the wavelength conversion element, the light emission of the organic EL sheet 16 can be controlled, and the light environment in the light environment adjustment region can be controlled easily and precisely.
Moreover, the energy saving effect at the time of maintaining a suitable light environment can also be anticipated by storing the energy generated by the solar cell sheet 12 as the energy for causing the organic EL sheet 16 to emit light and applying it as necessary.
In addition, the structure of a thin film solar cell is not limited to 1st Embodiment.

FIG. 2 is a schematic cross-sectional view showing a second embodiment of the thin-film solar cell. The thin film solar cell 20 of the second embodiment shown in FIG. 2 includes the solar cell sheet 12, the organic EL sheet 16, and the light control unit 14 in this order from the sunlight receiving side. In this embodiment, the light transmitted through the solar cell sheet 12 is supplied to the transmitted light environment adjustment region through the organic EL sheet 16. When the amount of light supplied is insufficient, the organic EL sheet 16 emits light by applying energy. In the light control part 14, by adjusting both the sunlight which permeate | transmitted the solar cell sheet | seat 12, and the light light-emitted in the organic electroluminescent sheet | seat 16, it controls suitably the light quantity which reaches | attains an optical environment adjustment area | region. .

Hereinafter, each member that can be provided in the thin film solar cell of the present disclosure will be described in detail.

(Solar cell sheet that transmits at least part of sunlight: solar cell sheet)
If the solar cell sheet 12 used for the thin film

solar cells

10 and 20 of this embodiment is a solar cell sheet which permeate | transmits at least one part of sunlight, there will be no restriction | limiting in particular. As a solar cell sheet that transmits at least part of sunlight, for example, an organic thin film solar cell sheet using an organic semiconductor, a dye-sensitized solar cell, a perovskite solar cell, an organic-inorganic hybrid solar cell, a tandem solar cell, Examples thereof include a CuO type solar cell. The solar cell sheet may be an inorganic solar cell sheet using a silicon type, a compound semiconductor, or the like.
As a solar cell sheet, an organic thin film solar cell sheet is preferable from the viewpoint that it has flexibility and can be manufactured by coating, so that the manufacturing cost is low and it is advantageous for enlargement, and a transmission type using an organic semiconductor A solar cell sheet or the like is more preferable.
Both the light transmission and absorption wavelengths of the organic thin film solar cell sheet can be appropriately set by selecting the material.
In this specification, the solar cell sheet means that “at least a part of sunlight is transmitted” means that the solar cell sheet transmits at least a part of the total light of sunlight and receives the solar cell sheet. It means to transmit to the side opposite to the side.
At least a part of sunlight is, for example, the amount of light of all light in the visible light region, the ultraviolet light region, the infrared light region, or the total light of sunlight. Refers to at least part of the light.

It is preferable that the solar cell sheet has selective light transmission, in other words, can selectively transmit light having a specific wavelength suitable for the light environment adjustment region.
For example, when a plant is cultivated in the light environment adjustment region, among the above, the selective light transmittance of the solar cell sheet has a wavelength in the visible light region (400 nm to 700 nm) useful for plant growth. It is preferable that it has the characteristic of transmitting light.
The solar cell sheet transmits a part of the light hitting the light receiving surface, and the rest is scattered or absorbed by the solar cell sheet and used for power generation.
By selecting a material used for the solar cell sheet, the wavelength of specific light is selectively transmitted or absorbed, so that the amount of light to be transmitted and the conversion efficiency can be adjusted.
In a preferred embodiment of the present disclosure, the solar cell sheet has selective light transmittance. In this case, the thin film solar cell of the present disclosure itself also has selective light transmittance. It goes without saying that light having at least one of a preferable light amount and a preferable wavelength can be selectively made to reach the light environment adjustment region on the side opposite to the side.

The transmittance when the solar cell sheet transmits at least part of sunlight is not particularly limited, but the transmittance of the thin film solar cell with respect to incident light is preferably 10% or more, and is 30% or more. Is more preferable.
For example, the transmittance is obtained by measuring the spectral irradiance in a predetermined wavelength region with respect to the transmitted light on the side opposite to the light-receiving side of the thin-film solar cell with a spectral radiometer, and the spectral irradiance of incident light (sunlight) It can be calculated by measuring the ratio to.

As a preferable aspect of the selective light transmittance of the solar cell sheet 12, for example, when used for plant cultivation in agricultural applications, a transmission wavelength of 400 nm to less than 500 nm (blue) and a transmission wavelength of 600 nm to less than 800 nm (red) contribute greatly to photosynthesis. It is preferable to transmit at least one of the light. In the case of a thin-film solar cell having absorption in the visible light region, the light transmittance is large at least at any of a transmission wavelength of 400 nm to less than 500 nm (blue) and a transmission wavelength of 600 nm to less than 800 nm (red), and the transmission wavelength is 500 nm to less than 600 nm. It is preferable that (green) light is absorbed by the solar cell sheet and used for power generation.

By selecting a solar cell sheet as described above, that is, having a good light transmittance in at least one of the blue region and the red region as a selective light transmittance, Electricity can be generated without impairing the growth effect.
In addition, when the solar cell sheet has selective light transmission, for example, by absorbing ultraviolet rays harmful to certain types of animals and plants to generate power, the arrival of ultraviolet rays to the light environment adjustment region is suppressed, and the light environment adjustment region The light environment in can be made more suitable for animals and plants.

The thickness of the solar cell sheet 12 is not particularly limited as long as it can transmit at least part of sunlight. For example, a sheet having a thickness corresponding to the purpose can be selected from 100 μm to 500 μm sheets.
A commercial item can be used for the solar cell sheet 12. As a commercial item, the organic solar cell in the Geoa solar power generation system of Mitsubishi Chemical Corporation etc. is mentioned.

(Transmission type organic EL sheet: organic EL sheet)
The thin film

solar cells

10 and 20 have an organic EL sheet 16.
The organic EL sheet 16 is not particularly limited as long as it is a sheet that can transmit at least part of sunlight, and a known organic EL sheet can be appropriately selected and used. The organic EL sheet 16 is preferably a flexible sheet.
The phrase “can transmit at least part of sunlight” means the same as described in the above-described solar cell sheet, and the organic EL sheet is at least one of the light transmitted by the solar cell sheet. It is preferable that the part can be transmitted.
The organic EL sheet 16 may be a double-sided emission type or a single-sided emission type. Among these, the single-sided emission type is preferable from the viewpoint that the emitted light directly reaches the light environment adjustment region and is used efficiently.
The organic EL sheet 16 may be integrally laminated on the thin film

solar cell

10 or 20.

As described above, the electric power applied to the light emission of the organic EL sheet 16 may be supplied from an external power source, or the electric power generated by the solar cell sheet 12 may be stored as the power source. By using the power generation energy by the solar cell sheet 12 as at least a part of the light emission energy of the organic EL sheet 16, the running cost of the thin film solar cell of this embodiment can be further reduced, which is preferable.

Examples of the organic EL sheet include an organic EL sheet having a light emitting layer or a plurality of organic layers including a light emitting layer between a pair of electrodes.
In the organic EL sheet 16, the emission color can be changed by mixing various emission dopants in the emission layer. For this reason, the organic EL sheet | seat 16 which light-emits the light of the wavelength range which contributes to plant growth, for example can be produced. In addition, since the organic EL sheet 16 is surface emitting, unlike a point light source such as a light emitting diode (LED) light source, the organic EL sheet 16 has a feature that light unevenness is difficult to occur, and can prevent plant growth unevenness due to light unevenness. There is also an advantage of low power consumption. Furthermore, when the transmissive organic EL sheet used in the present embodiment does not emit light, it is preferable that sunlight can be transmitted and sunlight necessary for plants can be supplied.

More specific examples of organic EL sheets include, for example, N, N′-dinaphthyl-N, N′-diphenylbenzidine on a polyethylene naphthalate (PEN) film with a transparent electrode (indium tin oxide: ITO). Visible light transmission type having (α-NPD) as a hole transporting layer, tris (8-hydroxyquinolinato) aluminum (Alq3) as an electron transporting light emitting layer, and using Ga—Zn—O (GZO) as a transparent electrode as an upper electrode Organic EL sheet.

(Light control unit that adjusts the amount of transmitted sunlight: Light control unit)
The thin film

solar cells

10 and 20 of the embodiment include a light control unit 14. As long as the light control part 14 can adjust the transmitted light amount of sunlight, there is no restriction | limiting in particular in a material and a structure. As the light control unit 14, for example, a sheet of a chromic material that changes color according to the amount of received light, a liquid crystal film, a blind that can be opened and closed, a removable cloth that has a light shielding property, and a member having a liquid flow path In addition, examples include, but are not limited to, a member that controls light transmittance by supplying a translucent or light-shielding liquid to the flow path.

Among them, in particular, from the viewpoint that the light quantity can be kept constant without requiring a light control operation according to the result of measuring the light quantity, the light control section 16 includes a chromic material. Is preferred. As a chromic material, a well-known chromic material, for example, a photochromic material, a gas chromic material, an electrochromic material, etc. are mentioned preferably.
Moreover, a commercially available light control device can also be employed as the light control unit as it is.

(Any member)
The thin film solar cell of the embodiment may further include an arbitrary member in addition to the solar cell sheet, the organic EL sheet, and the light control unit.
Optional members include, for example, a wavelength conversion unit that converts at least part of sunlight into light having a wavelength that is suitable for plant photosynthesis or suppresses photosynthesis, and reinforcement for improving the physical strength of the thin-film solar cell. Examples thereof include a sheet, an adhesive layer that improves the adhesion between adjacent sheets or members, a sealing material that suppresses moisture permeation into the solar cell, oxygen permeation, and the like, and a protective sheet.

(Wavelength converter)
The thin-film solar cell of the embodiment preferably further includes a wavelength conversion unit that converts the wavelength of light (transmitted light) incident via the solar cell sheet on the side opposite to the sunlight incident side.
The thin-film solar cell is provided with a wavelength conversion unit to reinforce light in a wavelength range effective for photosynthesis of plants absorbed by the solar cell sheet or organic EL sheet, or to absorb ultraviolet rays harmful to animals and plants. The amount reaching the environmental adjustment area can be suppressed.
For example, the wavelength conversion unit absorbs harmful ultraviolet light or blue light in the sunlight, converts it into useful visible light, and emits light in the wavelength region useful for plant photosynthesis as fluorescence. Therefore, it is preferable to absorb light in the wavelength range of 250 nm to 650 nm and emit fluorescence in the wavelength range of 450 nm to 700 nm. When the fluorescence emission wavelength region is within this range, when the thin film solar cell is used for plant growth, a sufficient effect of promoting photosynthesis for the plant can be obtained.

As the wavelength conversion unit, for example, a fluorescent radioactive net described in Japanese Patent No. 5505630 or a fluorescent radioactive sheet is preferably exemplified.
The fluorescent radiation net or the fluorescent radiation sheet can attenuate ultraviolet rays having a wavelength range of 250 to 320 nm. Each of the fluorescent radiation net or the fluorescent radiation sheet contains a thermoplastic resin capable of forming a net or a sheet and a fluorescent dye such as a fluorescent dye or a fluorescent pigment. Examples of fluorescent dyes include perylene dyes, pyrene dyes, xanthene dyes, thioxanthene dyes, coumarin dyes, and the like. Only 1 type of fluorescent dye may be used and it may use 2 or more types together according to the objective.

The thin-film solar cell 10 of the present embodiment can further include a light amount measuring unit that measures the amount of transmitted light that is incident on the solar cell sheet 12 and transmitted through the solar cell sheet 12.
Examples of the light quantity measuring means include an illuminometer used for measuring the light environment for photosynthesis of plants, a photon sensor having sensitivity in the photosynthesis effective wavelength region, and the like. By having such a light quantity measuring means, it is possible to design the organic EL sheet 16 to emit light when the quantity of transmitted light does not reach a predetermined amount.

FIG. 3: is a schematic sectional drawing which shows 3rd Embodiment of a thin film solar cell provided with a wavelength conversion part. A thin film solar cell 30 shown in FIG. 3 has a configuration in which the thin film solar cell 10 shown in FIG.
The thin-film solar cell 30 shown in FIG. 3 includes a solar cell sheet 12, a light control unit 14, an organic EL sheet 16, and a wavelength conversion unit 18 in this order from the light receiving side.
Taking plant growth as an example, in the thin film solar cell 30 of the third embodiment, light in a wavelength band useful for photosynthesis of plants out of sunlight passes through the thin film solar cell 30 and reaches the plant. . Part of light in a wavelength band that is not useful for photosynthesis is used for power generation in the solar cell sheet 12. In addition, a part of light in a wavelength band that is not useful for photosynthesis reaches the wavelength conversion unit 18, and is converted into light of a desired wavelength, for example, light in a wavelength band necessary for photosynthesis, by the wavelength conversion unit, to the plant. Irradiated to reinforce light in a wavelength band necessary for photosynthesis.
Also in the thin film solar cell 30 of the third embodiment, when sunlight is not sufficiently irradiated at night, rainy weather, cloudy weather, etc., power is generated by the solar cell sheet 12 and supplied from the stored power or an external power source. When the organic EL sheet 16 emits light using the electric power to be generated, the amount of light necessary for the photosynthesis of the plant can be ensured.

The configuration of the thin-film solar cell having the wavelength conversion unit 18 is not limited to the mode illustrated in FIG. 3. For example, the solar cell sheet 12, the light control unit 14, the wavelength conversion unit 18, and the organic EL sheet 16 are arranged from the light receiving side. The aspect provided in this order, the aspect provided with the solar cell sheet 12, the organic EL sheet 16, the light control part 14, and the wavelength conversion part 18 in this order from the light-receiving side. The aspect provided with the solar cell sheet 12, the organic EL sheet 16, the wavelength conversion part 18, and the light control part 14 in this order may be sufficient. In addition, from the viewpoint of expanding the range of selection for controlling the light environment, when the wavelength conversion unit 18 is provided, the configuration of the thin-film solar cell 30 illustrated in FIG. 3 is preferable.

According to the thin-film solar cell of the third embodiment, control of sunlight permeability, power generation by a solar cell sheet, light irradiation by an organic EL sheet, and in a preferred aspect, further a necessary wavelength by a wavelength conversion unit By combining the band light reinforcement, the target light environment can be maintained for a long time. Moreover, since the light environment can be adjusted as desired, its application range is wide.

Hereinafter, an example in which the thin film solar cell 30 of the third embodiment shown in FIG. 3 is used for plant cultivation will be described in detail.
FIG. 4 is a schematic diagram showing a usage mode and light state of the thin-film solar cell 30 when the amount of sunlight is large, such as during daytime when the weather is good in midsummer. In FIGS. 4 to 8 below, the light is represented by arrows or rectangles with the signs (a) to (f), and the area of the area partitioned by the arrows or rectangles schematically indicates the amount of light.
4 to 8, the region where the plant is schematically described on the side opposite to the light receiving side of the thin-film solar cell 30 corresponds to the light environment adjustment region shown in FIG.
In FIG. 4, the area (a) indicates sunlight that contributes to the growth of the plant among the irradiation light from the sun, and the area indicated by (b) contributes to the growth of the plant dimmed by the dimming unit 14. The area | region shown by (c) shows the sunlight which is absorbed by the solar cell sheet 12 with a part of sunlight which does not contribute so much to plant growth, and is used for electric power generation. The area shown by (d) shows a part of sunlight that does not contribute much to the growth of the plant, and (e) shows that the light shown by (d) is attenuated by the dimming unit 14 and is fluorescent in the wavelength conversion unit 18. The light absorbed by the pigment is shown, and (f) shows the light that is wavelength-converted via the wavelength converter 18 and greatly contributes to plant photosynthesis.

As shown in FIG. 4, since the sunlight is too strong during the daytime in midsummer, when the plant to be cultivated is a leafy vegetable or the like that causes sunburn, as shown in FIG. Part of the sunlight (a) that contributes to the growth of the plant is shielded by the light control unit 14, and the remaining part (b) that is set to a light quantity suitable for plant growth passes through the light control unit 14 and the transparent organic EL sheet 16. The plant is then irradiated to grow the plant.
Light (c) in the wavelength region that does not contribute much to the photosynthesis of plants is absorbed by the solar cell sheet 12 and used for power generation. Part (d) of the light in the wavelength region that does not contribute much to the photosynthesis of plants is light (e) that is attenuated by the light control unit 14 and absorbed by the wavelength conversion unit 18. The wavelength is converted, and the plant is irradiated as light (f) that greatly contributes to the photosynthesis of the plant.
As shown in FIG. 4, when the light environment is suitable for plant growth, the organic EL sheet 16 does not emit light.

FIG. 5 is a schematic diagram showing a usage mode of the thin-film solar cell 30 and a light state when the amount of sunlight is moderate during a sunny day.
In FIG. 5, (a), (c), (d), and (f) indicate the same light as shown in FIG.
As shown in FIG. 5, when the amount of sunlight is moderate during a sunny day, light control by the light control unit 14 is not performed.
The sunlight (a) that contributes to the growth of the plant passes through the light control unit 14 and the transparent organic EL sheet 16, and is irradiated to the plant in an amount sufficient for growing the plant. Light (c) in the wavelength region that does not contribute much to the photosynthesis of plants is absorbed by the solar cell sheet 12 and used for power generation. Further, a part (d) of the light in the wavelength region that does not contribute much to the photosynthesis of the plant is converted into light (f) having a wavelength that contributes to the photosynthesis of the plant via the wavelength conversion unit 18 and irradiated to the plant. The As a result, a light environment useful for plant growth can be maintained.
As shown in FIG. 5, when the light environment is suitable for plant growth, the organic EL sheet 16 does not emit light.

FIG. 6 is a schematic diagram illustrating a usage mode and a light state when adjusting the amount of light irradiated to the plant by the light control unit 14 of the thin-film solar cell 30.
In FIG. 6, (a) and (b) show the same light as shown in FIG.
When the sunshine hours are long as in summer, the light control unit 14 shields sunlight (a) from light and light through the light control unit 14 and the transparent organic EL sheet 16 in a predetermined time zone in the morning and evening. Thus, by setting the light (b) irradiated to the plant to almost zero, a short day treatment for controlling the irradiation time of sunlight can be performed to obtain a desired sunshine time.
Similarly to FIG. 4, light (c) in a wavelength region that is not significantly involved in plant photosynthesis is absorbed in the solar cell sheet 12 and used for power generation.

FIG. 7 is a schematic diagram showing a usage mode and light state of the thin-film solar cell 30 when sunlight is not irradiated, such as at night. In FIG. 6, (g) indicates light emitted from the organic EL sheet 16.
As shown in FIG. 7, light (g) supplied from the organic EL sheet 16 is irradiated to the plant as needed even at night when sunlight cannot be obtained, or in the winter morning or evening when the sunshine time is short. Irradiation of light (g) useful for plant growth to the plant can be continued for an arbitrary time. By applying this method, plant growth can be promoted by irradiating a certain amount of light for a long time. It is also possible to irradiate a certain amount of light continuously at a necessary time during the day.

Next, the aspect of the thin film solar cell 30 of the third embodiment at the time of cloudy or rainy weather will be described. The symbols (a) to (g) indicate the same light as shown in FIGS.

FIG. 8 is a schematic view showing a use mode of the thin-film solar cell 30 and a light state during a rainy or cloudy day.
As shown in FIG. 8, even in the rainy or cloudy day, sunlight (a) that contributes to the growth of plants is radiated slightly. Since the amount of received sunlight (a) that contributes to the growth of the plant is small, the light control unit 14 does not block the light, and the received sunlight (a) passes through the light control unit 14 and the transparent organic EL sheet 16. The plant is irradiated. Light (c) in a wavelength region that does not contribute much to plant photosynthesis in sunlight is absorbed by the solar cell sheet 12 and used for power generation.
On the other hand, when the amount of received sunlight is small, a sufficient amount of light for plant growth cannot be obtained. Therefore, energy (g) emitted from the organic EL sheet 16 is emitted by applying energy to the organic EL sheet 16 to emit light. The plant is irradiated. As a result, it is possible to maintain a light environment useful for growing plants even in rainy weather or cloudy weather when the amount of sunlight irradiation is small. Note that part of the light (g) emitted from the organic EL sheet 16 may be converted to a wavelength that greatly contributes to the photosynthesis of the plant via the wavelength conversion unit 18 and may be irradiated to the plant.
From the examples shown in FIGS. 4 to 8, by using the thin film solar cell 30 of the present embodiment, the plant can be used throughout the day, regardless of the season, regardless of the weather such as fine weather, cloudy weather, and rainy weather. It can be seen that a light environment suitable for growing can be maintained.

When the thin-film solar cell of the present embodiment described above is used for growing crops, for example, a dimming function that operates a dimming unit to block light when there is a large amount of solar radiation from morning to evening, and an amount of solar radiation in the daytime When there is little light, and when combined with lighting using organic EL sheets at night, light of the desired illuminance is applied to the crop every day for a certain period of time, regardless of fluctuations in the sunshine hours depending on the season, in plant factories and plastic houses using sunlight. Can be supplied.
As a result, it is possible to control the timing of growth, shipment, etc. of crops, and it is possible to achieve high-profit agriculture through planned production.
In a known artificial light plant factory, for example, the energy required for light irradiation of an LED light source or the like is 100% electric energy supplied from the outside. On the other hand, in the thin film solar cell of the present embodiment, sunlight can be used as it is, and furthermore, power can be generated using light in a wavelength band that does not contribute to the cultivation of agricultural products. Cost can be reduced.
Since the thin-film solar cell of the present embodiment has a dimming unit, the dimming function effectively blocks midsummer excessive light and effectively suppresses undesired rises in the temperature in the greenhouse, light damage to crops, and the like. be able to.

When using the thin film solar cell of this embodiment in a plant growing factory, a greenhouse, etc., it is not necessary to use the thin film solar cell for all of the facilities, and the thin film solar cell is applied to at least a part of the sunlight receiving surface. Even if it only does, there exists an effect of this indication. On the other hand, since the thin film solar cell of this indication can be used for the whole area | region of the light-receiving surface of sunlight, electric power generation in a large area is attained, and the generated electric power can also be supplied outside.
As described above, in the known solar cell panel that does not transmit light, the use of about 30% of the total area of the farmland is the limit in order to maintain the plant growth environment. The solar cell can be installed in 100% of the total area of the farmland, and even if the power generation efficiency by the solar cell sheet is slightly lower than the power generation efficiency of the conventional fixed inorganic solar cell panel, the total power generation amount Is expected to be larger.

Further, by using the thin film solar cell of the present disclosure not only for plants such as agricultural crops but also for poultry houses, livestock houses, fish culture ponds, etc., the growth environment can be controlled to a light environment suitable for animal growth. . Furthermore, it is expected that a suitable light environment is controlled by applying the thin film solar cell of the present disclosure when used in outer space, for example, when a human lives in a space colony.

Hereinafter, the thin film solar cell of the present disclosure will be described in detail with reference to examples, but the thin film solar cell of the present disclosure is not limited to the examples shown below.

[Example 1]
A thin-film solar cell 1 having a layer configuration shown in FIG. 1 including a solar cell sheet, a light control unit, and an organic EL sheet in this order was produced from the sunlight receiving side. Details of each member are as follows.

Solar cell sheet: (Organic thin film solar cell sheet) Power Plastic, Medium Red: Konarka Inc. Light control part: Light control film (LCF-1103DHA, Hitachi Chemical Co., Ltd.)
Organic EL sheet: An organic sheet having α-NPD as a hole transport layer, Alq3 as an electron transporting light emitting layer, and GZO as an upper transparent electrode on a PEN film with a transparent electrode (ITO)

(Evaluation of light transmission)
The light transmittance of the obtained thin film solar cell 1 was measured and evaluated as the illuminance of the light transmitted through the thin film solar cell 1 with a spectroradiometer (portable spectroradiometer MS-720, manufactured by Eihiro Seiki Co., Ltd.). . The result is shown in the graph of FIG.
As is clear from FIG. 9, it was confirmed that the illuminance in the vicinity of wavelengths 450 nm and 650 nm was high, the light transmittance was good, and the light transmittance in the red wavelength band particularly suitable for photosynthesis was excellent.

(Evaluation of power generation characteristics)
The power generation characteristics of the obtained thin-film solar cell 1 were measured and evaluated using a DC voltage / current source monitor (6241A: ADMT) and a solar simulator (System House Sunrise: automatic measurement software GP-IB library). The result is shown in the graph of FIG.
FIG. 10 shows the current-voltage characteristics of the thin-film solar cell 1 measured under irradiation with actual sunlight, similar to the measurement of the light transmission in FIG.
Table 1 below shows the characteristics of the thin-film solar cell 1 measured under actual sunlight irradiation as in FIG.

(Evaluation of light emission of organic EL sheet)
In the obtained thin film solar cell 1, the light emission characteristics of the organic EL sheet were evaluated by the following methods.
The measuring device used for the evaluation of the light emission characteristics is an ADMT 6241A as a voltage source and an ammeter, and the luminance meter is Konica Minolta Sensing LS-100. In addition, System House Sunrise W32-R6243IVL3-R was used as measurement software.
The luminance-voltage characteristics of the thin film solar cell 1 are shown in Table 2.
From the results in Table 2, it can be seen that the thin-film solar cell 1 can emit light from the organic EL sheet by using the organic thin-film solar cell described in Table 1. It can also be seen that the organic EL sheet has light emission characteristics sufficient to make up for the shortage of sunlight useful for growing plants at night, rainy weather, and cloudy weather.

(Application to plant cultivation)
A model greenhouse having a width of 150 cm, a length of 210 cm, and a height of 190 cm was produced, and the obtained thin-film solar cell 1 was placed on the top surface of the model greenhouse.
As a control example, a comparative model greenhouse having the same size and a transparent vinyl chloride sheet disposed on the top surface was prepared.
A model greenhouse and a comparative model greenhouse were placed outdoors, and under the same conditions, sanche, a leafy vegetable, was cultivated inside. After 4 weeks, the growth state of Sanche was compared. When using the model greenhouse in which the thin-film solar cell 1 of Example 1 was installed on the top surface, it was confirmed that the growth of the plant was smoother than when the comparative model greenhouse was used.

[Example 2]
In the thin film solar cell 1 of Example 1 having the layer configuration shown in FIG. 1, the organic thin film solar cell sheet 12 is replaced with the solar cell sheet 12 having the following configuration, and further on the side opposite to the light receiving direction of the organic EL sheet 16. The organic thin-film solar cell 2 of Example 2 having the wavelength conversion unit 18 having the layer configuration shown in FIG. 3 was produced in the same manner as Example 1 except that the following wavelength conversion unit 18 was provided.
Solar cell sheet: Organic thin-film solar cell sheet (Bulk hetero in which transparent PEN film with ITO transparent electrode is mixed with poly (3-hexylthiophene) (P3HT) and [6,6] phenyl-C61-methylbutyrate (PCBM) A transparent solar cell sheet with a GZO transparent electrode formed after producing a power generation layer with a structure)
Wavelength conversion part: fluorescent film made of polyethylene terephthalate (PET) resin containing 0.02% by mass of Lumogen Red 305 manufactured by BASF

(Evaluation of light transmission)
The light transmittance of the obtained thin film solar cell 2 was evaluated in the same manner as the thin film solar cell 1 of Example 1. The result is shown in the graph of FIG.
As is clear from FIG. 11, the illuminance in the vicinity of wavelengths 450 nm and 650 nm is large, the light transmittance is good, the light transmittance in the red wavelength band is particularly suitable for photosynthesis, and the red wavelength is higher than other wavelength ranges It was confirmed that the light transmittance of the band was larger.
Moreover, in contrast with FIG. 11 and FIG. 9, it turns out that the amount of light irradiation of the wavelength band which contributes greatly to the photosynthesis of a plant improves more by providing a thin film solar cell further with a wavelength conversion part.

The thin film solar cell of the present embodiment can maintain a desired light environment regardless of the amount of received sunlight, so that it can maintain a desired light environment, such as a plant breeding factory, a greenhouse such as a greenhouse, a poultry house, a livestock house, an aquaculture pond, etc. It is suitable for application to animal breeding facilities.

The disclosure of Japanese Patent Application 2016-010051 filed on January 21, 2016 is incorporated herein by reference.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

Claims

A transmissive thin film solar cell having a solar cell sheet that transmits at least part of sunlight, a transmissive organic EL sheet, and a light control unit that adjusts the amount of transmitted sunlight.
The transmission type thin film solar cell according to claim 1, comprising the solar cell sheet, the light control unit, and the transmission type organic EL sheet in this order from a sunlight incident side.
The transmission type thin film solar cell according to claim 1, wherein the solar cell sheet, the transmission type organic EL sheet, and the light control unit are provided in this order from the sunlight incident side.
The transmissive thin-film solar cell according to any one of claims 1 to 3, wherein the solar cell sheet has selective light transmittance.
The transmissive thin film solar cell according to claim 4, wherein the selective light transmittance is a characteristic of transmitting light in a visible light region.
The transmission thin film solar cell according to any one of claims 1 to 5, wherein the solar cell sheet is an organic solar cell sheet.
7. The wavelength converter according to claim 1, further comprising a wavelength conversion unit that converts a wavelength of light incident through the solar cell sheet on a side opposite to a sunlight incident side of the solar cell sheet. The transmissive thin film solar cell described.
Further, the transmission type organic EL sheet has a light amount measuring means for measuring the amount of transmitted light transmitted through the solar cell sheet, and the transmitted type organic EL sheet when the amount of transmitted light measured by the light amount measuring means does not reach a predetermined amount. The transmissive thin-film solar cell according to any one of claims 1 to 7, wherein energy is applied to the substrate to emit light.