BACKGROUND
The present invention relates, in general, to bifacial photoactive devices.
In recent times, bifacial photoactive devices have been employed to absorb direct radiation from one side and radiation reflected off a nearby surface from the other side. Conventional bifacial photoactive devices have utilized amorphous silicon and micro-silicon in their photoactive cells. However, conventional bifacial photoactive devices suffer from several disadvantages. Silicon-based photoactive cells work efficiently only in direct radiation. Therefore, the use of silicon-based photoactive cells in bifacial photoactive devices has failed to achieve high efficiency as would be expected from any bifacial photoactive device. Moreover, silicon-based photoactive cells are quite expensive. This makes conventional bifacial photoactive devices very expensive considering the low efficiencies they yield.
In light of the foregoing discussion, there is a need for a bifacial photoactive device that has a higher efficiency at a lower cost, compared to conventional bifacial photoactive devices.
SUMMARY
An object of the present invention is to provide a bifacial photoactive device that has a higher efficiency, compared to conventional bifacial photoactive devices.
Another object of the present invention is to provide a bifacial photoactive device that has a lower cost, compared to conventional bifacial photoactive devices.
Embodiments of the present invention provide a bifacial photoactive device. The bifacial photoactive device has a first side and a second side. The bifacial photoactive device includes one or more first photoactive cells on the first
side and one or more second photoactive cells on the second side. The first photoactive cells are configured to receive direct radiation and generate charge-carriers upon activation by direct radiation. The second photoactive cells are configured to receive diffused radiation and generate charge-carriers upon activation by diffused radiation. Diffused radiation may, for example, include at least one of: reflected direct radiation or indoor light radiation. Direct radiation and diffused radiation may, for example, be electromagnetic radiations, such as Infra-Red (IR) radiation, Radio waves, Microwaves, X-rays, Gamma rays, visible spectrum, and Ultra-Violet (UV) radiation.
The first photoactive cells may be any type of photoactive cells, for example, semiconductor-based photoactive cells, thin-film photoactive cells, organic photoactive cells, and so on. In accordance with an embodiment of the present invention, each of the first photoactive cells is an organic photoactive cell. Each of the second photoactive cells is an organic photoactive cell.
In accordance with an embodiment of the present invention, the first photoactive cells and the second photoactive cells are flexible and allow modification in the shape of the bifacial photoactive device.
In accordance with an embodiment of the present invention, the first photoactive cells could be connected in a first predefined manner and encapsulated to form a first photoactive module, while the second photoactive cells could be connected in a second predefined manner and encapsulated to form a second photoactive module. In such a case, the first photoactive cells and the second photoactive cells are separable, and are capable of functioning independent of each other.
In accordance with an embodiment of the present invention, each of the first photoactive cells includes a first band gap material, such as poly (3-hexylthiophene) (P3HT), or poly (9,9-dihexylfluorene-alt-bithiophene) (F6T2),
while each of the second photoactive cells includes a second band gap material,
such as poly[2,6-(4,4-bis-(2-ethylhexyl)-4H- cyclopenta[2,1-b;3,4-
b[prime]]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), or poly[(4,40-
bis(2- ethylhexyl)dithieno[3,2-b:20,30-d]silole)-2,6-diyl-alt-(2,1,3-
benzothiadiazole)-4,7-diyl] (PSBTBT).
In accordance with an embodiment of the present invention, the first photoactive cells and the second photoactive cells are configured to allow transmission of radiation through the bifacial photoactive device. Accordingly, the first photoactive cells and the second photoactive cells may be made transparent or semi-transparent. In accordance with an embodiment of the present invention, the first photoactive cells have first predefined transmittance and the second photoactive cells have a second predefined transmittance.
The bifacial photoactive device is configured to be placed on a surface of an enclosed area, in accordance with an embodiment of the present invention. The bifacial photoactive device is, therefore, suitable for use in windows, curtains, doors, wind screens of vehicles, and other suitable applications requiring transparency or semi-transparency.
Organic photoactive cells work efficiently even in diffused radiation. Moreover, organic photoactive cells have a lower cost, compared to silicon-based photoactive cells. Therefore, the bifacial photoactive device has a higher efficiency at a lower cost, compared to conventional bifacial photoactive devices.
BRIEF DESCRIPTION OF DRAWINGS
Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:
FIG. 1 depicts a bifacial photoactive device, in accordance with an embodiment
of the present invention;
FIG. 2 depicts an organic photoactive cell, in accordance with an embodiment of
the present invention;
FIGs. 3A and 3B depict a method of manufacturing a bifacial photoactive device,
in accordance with an embodiment of the present invention;
FIGs. 4A and 4B depict a method of manufacturing a bifacial photoactive device,
in accordance with another embodiment of the present invention;
FIGs. 5A and 5B depict a method of manufacturing a bifacial photoactive device,
in accordance with yet another embodiment of the present invention;
FIG. 6 depicts a system for manufacturing a bifacial photoactive device, in
accordance with an embodiment of the present invention;
FIG. 7 depicts a method of manufacturing a bifacial photoactive device, in
accordance with an embodiment of the present invention;
FIG. 8 depicts a bifacial photoactive device placed on the surface of an enclosed
area, in accordance with an embodiment of the present invention; and
FIG. 9 depicts a side view of the bifacial photoactive device, in accordance with
an embodiment of the present invention.
DETAILED DESCRIPTION
Various embodiments of the present invention provide a bifacial photoactive device and a method and system for manufacturing the bifacial photoactive device. The bifacial photoactive device has a first side and a second side. A 'bifacial photoactive device' is defined as a photoactive module that is configured to receive radiation from two sides. The bifacial photoactive device includes one or more first photoactive cells on the first side and one or more second photoactive cells on the second side. A 'photoactive cell' is defined as a cell whose functioning is based on activation of electrons due to incident photons.
The first photoactive cells are configured to receive direct radiation, and generate charge-carriers upon activation by direct radiation. The first photoactive cells could be any type of photoactive cells, for example, semiconductor-based photoactive cells, thin-film photoactive cells, organic photoactive cells, and so on. In accordance with an embodiment of the present invention, each of the first photoactive cells is an organic photoactive cell.
The second photoactive cells are configured to receive diffused radiation and generate charge-carriers upon activation by diffused radiation. Each of the second photoactive cells is an organic photoactive cell.
Direct radiation and diffused radiation may, for example, be electromagnetic radiations, such as Infra-Red (IR) radiation, Radio waves, Microwaves, X-rays, Gamma rays, visible spectrum, and Ultra-Violet (UV) radiation. 'Direct radiation' is defined as radiation that is incident directly on a photoactive cell. 'Diffused radiation' is defined as radiation that is incident indirectly on a photoactive cell. Diffused radiation may, for example, include at least one of: reflected direct radiation (e.g., radiation reflected off a nearby surface), indoor light radiation, or radiation that is not absorbed by the first photoactive cells. In an embodiment of the present invention, an organic lighting device may act as a source of diffused radiation.
Referring now to figures, FIG. 1 depicts a bifacial photoactive device 100, in accordance with an embodiment of the present invention. Bifacial photoactive device 100 has a first side 102 and a second side 104. Bifacial photoactive device 100 includes one or more first photoactive cells (not shown in FIG. 1) on first side 102 and one or more second photoactive cells (not shown in FIG. 1) on second side 104.
The first photoactive cells are configured to receive direct radiation from sun. These direct radiations lead to generation of charge-carriers in the first
photoactive cells. The first photoactive cells may be any type of photoactive cells, for example, semiconductor-based photoactive cells, thin-film photoactive cells, organic photoactive cells, and so on. In accordance with an embodiment of the present invention, each of the first photoactive cells is an organic photoactive cell.
The second photoactive cells are configured to receive diffused radiation and generate charge-carriers upon activation by diffused radiation. Diffused radiation include at least one of: reflected direct radiation (e.g., radiation reflected off a nearby surface), indoor light radiation, or radiation that is not absorbed by the first photoactive cells. The radiations not absorbed by the first photoactive cells and passed on to the second photoactive cells may be termed as indirect radiations. In an embodiment of the present invention, the terms 'diffused radiation' and 'indirect radiation' are interchangeable and the indirect radiation may also be redirected by any other surface.
In an embodiment of the present invention, the one or more second photoactive cells are organic photoactive cells.
In accordance with an embodiment of the present invention, the first photoactive cells and the second photoactive cells are flexible and allow modification in the shape of bifacial photoactive device 100.
In accordance with an embodiment of the present invention, the first photoactive cells could be connected in a first predefined manner and encapsulated to form a first photoactive module, while the second photoactive cells could be connected in a second predefined manner and encapsulated to form a second photoactive module. In such a case, the first photoactive cells and the second photoactive cells are separable, and are capable of functioning independent of each other.
In accordance with an embodiment of the present invention, each of the first photoactive cells includes a first band gap material that is capable of absorbing direct radiation. The first band gap material may, for example, be poly(3-hexylthiophene) (P3HT), or poly(9,9-dihexylfluorene-alt-bithiophene) (F6T2).
In accordance with an embodiment of the present invention, each of the
second photoactive cells includes a second band gap material that is capable of
absorbing diffused radiation. The second band gap material may, for example, be
poly[2,6-(4,4-bis-(2-ethylhexyl)-4H- cyclopenta[2,1-b;3,4-b[prime]]dithiophene)-
alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), or poly[(4,40-bis(2-
ethylhexyl)dithieno[3,2-b:20,30-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (PSBTBT).
In accordance with an embodiment of the present invention, the first photoactive cells and the second photoactive cells are configured to allow transmission of radiation through bifacial photoactive device 100.
In accordance with an embodiment of the present invention, the first photoactive cells have a first predefined transmittance, while the second photoactive cells have a second predefined transmittance. 'Transmittance' is defined as a fraction of incident radiation that passes through the cells. In a first embodiment of the present invention, the first predefined transmittance is such that the first photoactive cells are semi-transparent and partially absorb direct radiation. In a second embodiment of the present invention, the first predefined transmittance is such that the first photoactive cells are transparent and allow all direct radiation to pass through them. In various embodiments of the present invention, the value of the second predefined transmittance is such that it enables the second photoactive cells to be transparent or semi-transparent. Accordingly, the first photoactive cells and the second photoactive cells may be made transparent or semi-transparent.
In an embodiment of the present invention, the bifacial photoactive device 100 is configured to be placed on the surface of an enclosed area. Bifacial photoactive device 100 is, therefore, suitable for use in windows, curtains, doors, wind screens of vehicles, and other suitable applications requiring transparency or semi-transparency. Details corresponding to the placement of bifacial photoactive device 100 have been provided in conjunction with FIG. 8 and FIG. 9.
It is to be understood that the specific designation for bifacial photoactive device 100 and its various components is for the convenience of the reader and is not to be construed as limiting bifacial photoactive device 100 to a specific size, shape, type, or arrangement of its components.
In accordance with an embodiment of the present invention, each of the first photoactive cells and the second photoactive cells is an organic photoactive cell. FIG. 2 depicts an organic photoactive cell 200, in accordance with an embodiment of the present invention. Organic photoactive cell 200 includes a substrate 202, a first electrode 204 formed over substrate 202, a hole-transport layer 206 formed over first electrode 204, a photoactive layer 208 formed over hole-transport layer 206, and a second electrode 210 formed over photoactive layer 208.
Substrate 202 allows a large amount of radiation incident on its surface to pass through with minimal reflection from its surface. Substrate 202 may, for example, be made of an optically-transparent material that is tolerant to moisture, UV radiation, abrasion, and natural temperature variations. Examples of such optically-transparent materials include, but are not limited to, glass, plastics, polycarbonates, polymers, and acrylics.
In accordance with an embodiment of the present invention, substrate 202 may be coated with an anti-reflective coating to reduce loss of radiation incident
on organic photoactive cell 200. The anti-reflective coating minimizes reflection occurring at a medium boundary between air and substrate 202.
A first conductive material could be used to form first electrode 204 over substrate 202. First electrode 204 is configured to allow transmission of radiation. Accordingly, the first conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the first conductive material.
A hole-transport material could be used to form hole-transport layer 206 over first electrode 204. Examples of the hole-transport material include, but are not limited to, Poly(3,4-ethylenedioxythiophene) (PEDOT), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS).
Hole-transport layer 206 allows incident radiation to pass through towards photoactive layer 208. In one example, hole-transport layer 206 may be made of a hole-transport material that is optically transparent in a specific region of the incident radiation, for example, the visible spectrum and/or IR radiation.
In accordance with an embodiment of the present invention, the thickness of hole-transport layer 206 could be adjusted to allow proper transmission of radiation and transportation of charge carriers simultaneously. For example, the thickness of hole-transport layer 206 may range from 30 nm to 150 nm.
A photoactive material could be used to form photoactive layer 208 over hole-transport layer 206. In one example, the photoactive material may include an active polymer and a fullerene-based electron acceptor. An active polymer is an organic polymer that generates charge carriers upon being activated by incident radiation. In another example, the photoactive material may include a
nano-particle-based electron acceptor, instead of a fullerene-based electron acceptor.
A second conductive material could be used to form second electrode 210 over photoactive layer 208. In accordance with an embodiment of the present invention, second electrode 210 is configured to allow transmission of radiation. In such a case, the second conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the second conductive material. In accordance with an alternative embodiment of the present invention, the second conductive material may be Aluminum, Silver, Calcium and Barium.
When radiation is incident over photoactive layer 208, electron-hole pairs are created in photoactive layer 208. Electrons and holes are separated at an interface between photoactive layer 208 and hole-transport layer 206, thereby generating a voltage. When a load is connected across first electrode 204 and second electrode 210, the generated voltage drives current, thereby producing electricity.
It is to be understood that the specific designation for organic photoactive cell 200 and its various components is for the convenience of the reader and is not to be construed as limiting organic photoactive cell 200 to a specific size, shape, type, or arrangement of its components.
In accordance with an alternative embodiment of the present invention, each of the first photoactive cells is a semiconductor-based photoactive cell. In accordance with an embodiment of the present invention, a semiconductor-based photoactive cell includes a substrate on which one or more photoactive elements are arranged. The photoactive elements may, for example, be
connected in a series and/or parallel arrangement. The photoactive elements may, for example, be made of mono-crystalline silicon (c-Si), poly-crystalline or multi-crystalline silicon (poly-Si or mc-Si), ribbon silicon, proto-crystalline silicon, nano-crystalline silicon (nc-Si or nc-Si:H), or germanium (Ge).
In accordance with another alternative embodiment of the present invention, each of the first photoactive cells is a thin-film photoactive cell. In accordance with an embodiment of the present invention, a thin-film photoactive cell includes a substrate on which a thin film of a suitable photoactive material is made. Examples of the photoactive material include, but are not limited to, cadmium telluride (CdTe), copper-indium diselenide (CulnSe2), copper indium/gallium diselenide (CIGS), gallium arsenide (GaAs), and gallium indium phosphide (GalnP2), and amorphous silicon (a-Si or a-Si:H).
FIGs. 3A and 3B depict how a bifacial photoactive device 300 is manufactured, in accordance with an embodiment of the present invention. Bifacial photoactive device 300 includes at least one first photoactive cell, shown as a first photoactive cell 302, and at least one second photoactive cell, shown as a second photoactive cell 304.
First photoactive cell 302 has a first front side 306 and a first rear side 308. In accordance with an embodiment of the present invention, first photoactive cell 302 is an organic photoactive cell, and cell layers 310 are formed on first rear side 308 of first photoactive cell 302. First photoactive cell 302 is configured to receive direct radiation from first front side 306, and generate charge-carriers upon activation by direct radiation.
Second photoactive cell 304 has a second front side 312 and a second rear side 314. In accordance with an embodiment of the present invention, second photoactive cell 304 is an organic photoactive cell, and cell layers 316 are formed on second rear side 314 of second photoactive cell 304. Second
photoactive cell 304 is configured to receive diffused radiation, and generate charge-carriers upon activation by diffused radiation. Second photoactive cell 304 may, for example, receive diffused radiation from second front side 312. In addition, second photoactive cell 304 may receive radiation not absorbed by first photoactive cell 302 from second rear side 314.
First photoactive cell 302 and second photoactive cell 304 are arranged back-to-back to form bifacial photoactive device 300. As depicted in FIGs. 3A and 3B, first photoactive cell 302 and second photoactive cell 304 are arranged in a manner that first rear side 308 of first photoactive cell 302 is adjacent to second rear side 314 of second photoactive cell 304.
In accordance with an embodiment of the present invention, the amount of direct radiation that is not absorbed by first photoactive cell 302 is transmitted towards second photoactive cell 304. Accordingly, first photoactive cell 302 and second photoactive cell 304 may be made transparent or semi-transparent. In accordance with an embodiment of the present invention, first photoactive cell 302 and second photoactive cell 304 include one or more electrodes that are configured to allow transmission of radiation that is not absorbed by first photoactive cell 302 towards second photoactive cell 304.
In accordance with an embodiment of the present invention, bifacial photoactive device 300 includes a covering member 318 arranged in between first photoactive cell 302 and second photoactive cell 304. Covering member 318 seals first rear side 308 of first photoactive cell 302 and second rear side 314 of second photoactive cell 304, as depicted in FIGs. 3A and 3B.
In accordance with an embodiment of the present invention, covering member 318 is configured to allow transmission of radiation that is not absorbed by first photoactive cell 302 towards second photoactive cell 304. Accordingly, covering member 318 may be made transparent or semi-transparent.
Covering member 318 has a first cover side 320 and a second cover side 322. First cover side 320 includes a first cavity in which first rear side 308 and cell layers 310 of first photoactive cell 302 are sealed. Second cover side 322 includes a second cavity in which second rear side 314 and cell layers 316 of second photoactive cell 304 are sealed. First cover side 320 and second cover side 322 may, for example, be attached to first rear side 308 and second rear side 314, respectively, using a glue.
Covering member 318 protects cell layers 310 and cell layers 316 against any mechanical or chemical damage. Covering member 318 is made of a transparent material. Examples of transparent material include glass, plastics, polycarbonates, polymers, and acrylics. In an embodiment of the present invention, covering member 318 is made of an epoxy material in an inert environment.
In accordance with an embodiment of the present invention, a getter is placed in between cell layers 310 and first cover side 320 and in between cell layers 316 and second cover side 322. The getter may, for example, be in the form of a thin sheet, or a thin coat. In accordance with an embodiment of the present invention, the getter is configured to allow transmission of radiation. Accordingly, the getter may be made transparent or semi-transparent. The getter may, for example, be capable of absorbing air and moisture, thereby protecting cell layers 310 and cell layers 316 against any damage due to air and moisture.
In accordance with a specific embodiment of the present invention, bifacial photoactive device includes a plurality of bifacial photoactive units arranged in a series and/or parallel arrangement to achieve a desired output. Each of the plurality of bifacial photoactive units includes one or more first photoactive cells similar to first photoactive cell 302 and one or more second photoactive cells
similar to second photoactive cell 304 encapsulated together to form a unitary one-piece unit.
FIGs. 4A and 4B depict how a bifacial photoactive device 400 is manufactured, in accordance with another embodiment of the present invention. Bifacial photoactive device 400 includes at least one first photoactive cell, shown as first photoactive cell 302, and at least one second photoactive cell, shown as second photoactive cell 304.
First photoactive cell 302 and second photoactive cell 304 are arranged back-to-back to form bifacial photoactive device 400. As depicted in FIGs. 4A and 4B, first photoactive cell 302 and second photoactive cell 304 are arranged in a manner that first rear side 308 of first photoactive cell 302 is adjacent to second rear side 314 of second photoactive cell 304.
Bifacial photoactive device 400 includes a covering member 402 arranged in between first photoactive cell 302 and second photoactive cell 304. Covering member 402 seals first rear side 308 of first photoactive cell 302 and second rear side 314 of second photoactive cell 304, as depicted in FIGs. 4A and 4B.
In accordance with an embodiment of the present invention, covering member 402 is configured to allow transmission of radiation that is not absorbed by first photoactive cell 302 towards second photoactive cell 304. Accordingly, covering member 402 may be made transparent or semi-transparent.
Covering member 402 has a first cover side 404 and a second cover side 406. First cover side 404 seals first rear side 308 and cell layers 310 of first photoactive cell 302, while second cover side 406 seals second rear side 314 and cell layers 316 of second photoactive cell 304.
In accordance with an embodiment of the present invention, first cover side 404 and second cover side 406 are attached to first rear side 308 and second rear side 314, respectively, using a glue with spacers 408. Spacers 408 facilitate a substantially uniform gap between first cover side 404 and first rear side 308, and between second cover side 406 and second rear side 314. Spacers 408 may, for example, be spherical or oval in shape. The size of spacers 408 may, for example, range from 200 nm to 300 nm.
In accordance with an embodiment of the present invention, covering member 402 is an insulating layer. Covering member 402 protects cell layers 310 and cell layers 316 against any mechanical or chemical damage. Covering member 402 may, for example, be made of plastics, polycarbonates, polymers, or acrylics.
In accordance with an embodiment of the present invention, a getter is placed in between cell layers 310 and first cover side 404 and in between cell layers 316 and second cover side 406. The getter may, for example, be in the form of a thin sheet, or a thin coat. In accordance with an embodiment of the present invention, the getter is configured to allow transmission of radiation. Accordingly, the getter may be made transparent or semi-transparent. The getter may, for example, be capable of absorbing air and moisture, thereby protecting cell layers 310 and cell layers 316 against any damage due to air and moisture.
FIGs. 5A and 5B depict how a bifacial photoactive device 500 is manufactured, in accordance with yet another embodiment of the present invention. Bifacial photoactive device 500 includes at least one first photoactive cell, shown as first photoactive cell 302, and at least one second photoactive cell, shown as second photoactive cell 304.
First photoactive cell 302 and second photoactive cell 304 are arranged back-to-back to form bifacial photoactive device 500. As depicted in FIGs. 5A
and 5B, first photoactive cell 302 and second photoactive cell 304 are arranged in a manner that first rear side 308 of first photoactive cell 302 is adjacent to second rear side 314 of second photoactive cell 304.
With reference to FIGs. 5A and 5B, first rear side 308 of first photoactive cell 302 and second rear side 314 of second photoactive cell 304 are attached using a glue with spacers 502. Spacers 502 facilitate a substantially uniform gap between first rear side 308 and second rear side 314, thereby avoiding any short circuit. Spacers 502 may, for example, be spherical or oval in shape. The size of spacers 502 may, for example, range from 200 nm to 300 nm.
It is to be understood that the specific designation for bifacial photoactive devices 300, 400 and 500 and their various components is for the convenience of the reader and is not to be construed as limiting bifacial photoactive devices 300, 400 and 500 to a specific size, shape, type, or arrangement of their components. For example, first photoactive cell 302 is not limited to an organic photoactive cell, and could be any other type of photoactive cell, such as a semiconductor-based photoactive cell, thin-film photoactive cell, and so on.
FIG. 6 depicts a system 600 for manufacturing a bifacial photoactive device, in accordance with an embodiment of the present invention. System 600 includes a first photoactive-cell manufacturing unit 602, a second photoactive-cell manufacturing unit 604, and an arranging unit 606.
First photoactive-cell manufacturing unit 602 is configured to manufacture at least one first photoactive cell, while second photoactive-cell manufacturing unit 604 is configured to manufacture at least one second photoactive cell. As described earlier, the at least one first photoactive cell is configured to receive direct radiation, while the at least one second photoactive cell is configured to receive diffused radiation.
Consider, for example, that each of the at least one first photoactive cell and the at least one second photoactive cell is an organic photoactive cell, and is manufactured as explained below.
First, a substrate is obtained. For example, an injection molding machine may be used to mold a polymeric material to form a substrate of a desired shape. The substrate may, for example, be made of an optically-transparent material that is tolerant to moisture, UV radiation, abrasion, and natural temperature variations. Examples of such optically-transparent materials include, but are not limited to, glass, plastics, polycarbonates, polymers, and acrylics.
Next, a first electrode is formed over the substrate. For example, a first conductive material may be deposited over the substrate to form the first electrode. The first electrode is configured to allow transmission of radiation. Accordingly, the first conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the first conductive material.
Subsequently, a hole-transport layer is formed over the first electrode. For example, a hole-transport material may be coated over the first electrode to form the hole-transport layer. Examples of the hole-transport material include, but are not limited to, Poly(3,4-ethylenedioxythiophene) (PEDOT), Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOTPSS).
Thereafter, a photoactive layer is formed over the hole-transport layer. For example, a photoactive material may be coated over the hole-transport layer to form the photoactive layer. In one example, the photoactive material may include an active polymer and a fullerene-based electron acceptor. In another example, the photoactive material may include a nano-particle-based electron acceptor, instead of a fullerene-based electron acceptor.
In accordance with an embodiment of the present invention, the
photoactive material is selected on the basis of the absorption spectrum of the
active polymer. Consequently, each of the at least one first photoactive cell
includes a photoactive layer that includes a first band gap material, while each of
the at least one second photoactive cell includes a photoactive layer that
includes a second band gap material. The first band gap material is capable of
absorbing direct radiation, while the second band gap material is capable of
absorbing diffused radiation. In other words, the first band gap material is
capable of absorbing a first portion of radiation, while the second band gap
material is capable of absorbing a second portion of radiation. The first portion of
radiation corresponds to a wavelength range that is shorter than that of the
second portion of radiation. The first band gap material may, for example, be poly
(3-hexylthiophene) (P3HT), or poly(9,9-dihexylfluorene-alt-bithiophene) (F6T2).
The second band gap material may, for example, be poly[2,6-(4,4-bis-(2-
ethylhexyl)-4H- cyclopenta[2,1 -b;3,4-b[prime]]dithiophene)-alt-4,7-(2,1,3-
benzothiadiazole)] (PCPDTBT), or poly[(4,40-bis(2- ethylhexyl)dithieno[3,2-b:20,30-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl](PSBTBT).
Finally, a second electrode is formed over the photoactive layer. For example, a second conductive material may be deposited over the photoactive layer to form the second electrode. In accordance with an embodiment of the present invention, the second electrode is configured to allow transmission of radiation. In such a case, the second conductive material may, for example, be a transparent conductive oxide, such as Indium Tin Oxide (ITO), Zinc Oxide, Aluminum-doped Zinc Oxide, and Fluorine-doped Tin Oxide (FTO). Alternatively, a suitable transparent conductive polymer may be used as the second conductive material. In accordance with an alternative embodiment of the present invention, the second conductive material may, for example, be Aluminum, Silver, Calcium and Barium.
Arranging unit 606 is configured to arrange the at least one first photoactive cell and the at least one second photoactive cell back-to-back to form the bifacial photoactive device.
In accordance with an embodiment of the present invention, arranging unit 606 arranges a covering member in between the at least one first photoactive cell and the at least one second photoactive cell, as depicted in FIGs. 3A and 3B and FIGs. 4A and 4B. Arranging unit 606 then attaches the covering member with the at least one first photoactive cell and the at least one second photoactive cell, so as to seal the at least one first photoactive cell and the at least one second photoactive cell.
In accordance with another embodiment of the present invention, arranging unit 606 attaches the at least one first photoactive cell and the at least one second photoactive cell using a glue with spacers, as depicted in FIGs. 5A and 5B.
In accordance with a specific embodiment of the present invention, first photoactive-cell manufacturing unit 602 could be configured to connect a plurality of first photoactive cells in a first predefined manner and encapsulate them to form a first photoactive module, while second photoactive-cell manufacturing unit 604 is configured to connect a plurality of second photoactive cells in a second predefined manner and encapsulate them to form a second photoactive module. The first predefined manner and the second predefined manner may, for example, be a desired series and/or parallel arrangement. In such a case, arranging unit 606 could be configured to arrange the first photoactive module and the second photoactive module back-to-back to form the bifacial photoactive device.
FIG. 6 is merely an example, which should not unduly limit the scope of the claims herein.
FIG. 7 depicts a method of manufacturing a bifacial photoactive device, in accordance with an embodiment of the present invention.
At step 702, at least one first photoactive cell is manufactured. At step 704, at least one second photoactive cell is manufactured. As described earlier, the at least one first photoactive cell is configured to receive direct radiation, while the at least one second photoactive cell is configured to receive diffused radiation.
Step 702 and step 704 may, for example, be performed by first photoactive-cell manufacturing unit 602 and second photoactive-cell manufacturing unit 604, respectively, as described above.
Subsequently, at step 706, the at least one first photoactive cell and the at least one second photoactive cell are arranged back-to-back to form the bifacial photoactive device.
In accordance with an embodiment of the present invention, step 706 includes arranging a covering member in between the at least one first photoactive cell and the at least one second photoactive cell, and attaching the covering member with the at least one first photoactive cell and the at least one second photoactive cell, as depicted in FIGs. 3A and 3B and FIGs. 4A and 4B.
In accordance with another embodiment of the present invention, step 706 includes attaching the at least one first photoactive cell and the at least one second photoactive cell using a glue with spacers, as depicted in FIGs. 5A and 5B.
In accordance with a specific embodiment of the present invention, step 702 could include connecting a plurality of first photoactive cells in a first predefined manner and encapsulating them to form a first photoactive module,
while step 704 could include connecting a plurality of second photoactive cells in a second predefined manner and encapsulating them to form a second photoactive module. The first predefined manner and the second predefined manner may, for example, be a desired series and/or parallel arrangement. In such a case, step 706 could include arranging the first photoactive module and the second photoactive module back-to-back to form the bifacial photoactive device.
It should be noted here that steps 702-706 are only illustrative and other alternatives can also be provided where steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. For example, step 702 and step 704 may be performed simultaneously.
FIG. 8 depicts bifacial photoactive device 100 placed on a surface 802 of an enclosed area 804, in accordance with an embodiment of the present invention.
Enclosed area 804 may, for example, be a three-dimensional space covered from all the sides. Enclosed area 804 may, for example, be a room, a vehicle, such as a car, a cubicle, or a building. Accordingly, surface 802 may, for example, be a window, a curtain, a door, or a wind screen.
Enclosed area 804 may be of various shapes and sizes. Enclosed area 804 may, for example, be in the form of a cube, a cuboid, a circular cylinder, a triangular cylinder, a pentagonal cylinder, a prism, a cone, a sphere and the like.
FIG. 9 depicts a side view of bifacial photoactive device 100 placed on surface 802, in an embodiment of the present invention.
Bifacial photoactive device 100 includes at least one first photoactive cell on first side 102 configured to receive direct radiation and at least one second photoactive cell on second side 104 configured to receive diffused radiation. Bifacial photoactive device 100 is placed on surface 802 of enclosed area 804 in a manner that the first photoactive cell is exposed to direct radiation and the second photoactive cell is facing the inner space of enclosed area 804.
Embodiments of the present invention provide a bifacial photoactive device and a manufacturing method and system thereof. The bifacial photoactive device includes one or more first photoactive cells on one side and one or more second photoactive cells on the other side. The first photoactive cells are configured to receive direct radiation, while the second photoactive cells are configured to receive diffused radiation. In accordance with an embodiment of the present invention, the first photoactive cells and the second photoactive cells are organic photoactive cells.
Organic photoactive cells work efficiently even in diffused radiation. Therefore, the bifacial photoactive device has a higher efficiency, compared to conventional bifacial photoactive devices.
In addition, organic photoactive cells have a lower cost. Therefore, the bifacial photoactive device has a lower cost, compared to conventional bifacial photoactive devices.
Moreover, organic photoactive cells may be made transparent or semi-transparent. Furthermore, organic photoactive cells may be manufactured in the form of flexible sheets. Therefore, the bifacial photoactive device manufactured from such organic photoactive cells may be utilized in a variety of applications requiring transparency or semi-transparency, for example, in windows, curtains, doors and wind screens of vehicles.
The bifacial photoactive device may also be used in various other applications. For example, an array of bifacial photoactive devices may be used to generate electricity on a large scale for grid power supply. In another example, bifacial photoactive devices may be used to generate electricity on a small scale for home/office use. Alternatively, bifacial photoactive devices may be used to generate electricity for stand-alone electrical devices, such as automobiles and spacecraft.
In the description herein for the embodiments of the present invention, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of the embodiments of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the present invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of the embodiments of the present invention.
Reference throughout this specification to "one embodiment", "an embodiment", or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of an embodiment of the present invention and not necessarily in all embodiments. Thus, respective appearances of the phrases "in one embodiment", "in an embodiment", or "in a specific embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present invention may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the
teachings herein and are to be considered as part of the spirit and scope of the present invention.
It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.
As used in the description herein and throughout the claims that follow, "a", "an", and "the" includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the present invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the present invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.
Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of the embodiments of the present invention will be employed without a corresponding use of other features without departing from the scope and spirit of the present invention as set forth.
Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the present invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this present invention, but that the present invention will include any and all embodiments and equivalents falling within the scope of the appended claims.

WHAT IS CLAIMED IS:
1. A bifacial photoactive device, the bifacial photoactive device having a first side
and a second side, the bifacial photoactive device comprising:
one or more first photoactive cells on the first side, the one or more first photoactive cells being configured to receive direct radiation and generate charge-carriers upon activation by direct radiation; and
one or more second photoactive cells on the second side, the one or more second photoactive cells being configured to receive diffused radiation and generate charge-carriers upon activation by diffused radiation, each of the one or more second photoactive cells being an organic photoactive cell.
2. The bifacial photoactive device of claim 1, wherein each of the one or more first photoactive cells are organic photoactive cells.
3. The bifacial photoactive device of claim 1, wherein the one or more first photoactive cells and the one or more second photoactive cells are flexible and allow modification in the shape of the bifacial photoactive device.
4. The bifacial photoactive device of claim 1, wherein the one or more first photoactive cells are connected in a first predefined manner and encapsulated to form a first photoactive module, and the one or more second photoactive cells are connected in a second predefined manner and encapsulated to form a second photoactive module, further wherein the one or more first photoactive cells and the one or more second photoactive cells are separable and capable of functioning independent of each other
5. The bifacial photoactive device of claim 1, wherein each of the one or more first photoactive cells comprises a first band gap material selected from the group
consisting of: poly (3-hexylthiophene) (P3HT), or poly (9,9-dihexylfluorene-alt-
bithiophene) (F6T2), and each of the one or more second photoactive cells
comprises a second band gap material selected from the group consisting of:
poly[2,6-(4,4-bis-(2-ethylhexyl)-4H- cyclopenta[2,1-b;3,4-b[prime]]dithiophene)-
alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT), or poly[(4,40-bis(2-
ethylhexyl)dithieno[3,2-b:20,30-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (PSBTBT).
6. The bifacial photoactive device of claim 1 is suitable for use in at least one of: windows, curtains, doors, and wind screens of vehicles.
7. A bifacial photoactive device comprising:
at least one first photoactive cell, the at least one first photoactive cell having a first front side and a first rear side, the at least one first photoactive cell being configured to receive direct radiation from the first front side and generate charge-carriers upon activation by direct radiation; and
at least one second photoactive cell, the at least one second photoactive cell having a second front side and a second rear side, the at least one second photoactive cell being configured to receive diffused radiation and generate charge-carriers upon activation by diffused radiation, the second rear side of the at least one second photoactive cell being adjacent to the first rear side of the at least one first photoactive cell,
wherein the amount of direct radiation that is not absorbed by the at least one first photoactive cell is transmitted towards the at least one second photoactive cell.
8. The bifacial photoactive device of claim 7, wherein the at least one first
photoactive cell and the at least one second photoactive cell comprise one or
more electrodes that are configured to allow transmission of radiation, that is
not absorbed by the at least one first photoactive cell, towards the at least
one second photoactive cell.
9. The bifacial photoactive device of claim 7 further comprising a covering member arranged in between the at least one first photoactive cell and the at least one second photoactive cell, wherein the covering member seals the first rear side of the at least one first photoactive cell and the second rear side of the at least one second photoactive cell.
10. The bifacial photoactive device of claim 9, wherein the covering member is configured to allow transmission of radiation that is not absorbed by the at least one first photoactive cell towards the at least one second photoactive cell.
11. The bifacial photoactive device of claim 9, wherein the covering member has a first cover side and a second cover side, the first cover side comprising a first cavity in which the first rear side of the at least one first photoactive cell is sealed, and the second cover side comprising a second cavity in which the second rear side of the at least one second photoactive cell is sealed.
12. The bifacial photoactive device of claim 7 further comprising a plurality of
bifacial photoactive units arranged in a series and/or parallel arrangement to
achieve a desired output, wherein each of the plurality of bifacial photoactive
units comprises one or more first photoactive cells and one or more second
photoactive cells encapsulated together to form a unitary one-piece unit.
13. A bifacial photoactive device substantially as herein above described in the
specification with reference to the accompanying drawings.