Photoelectrochemical cells for conversion of solar energy to electricity
First Claim
1. A tandem photovoltaic device comprising a sandwich structure of at least three semiconductor layers each separated from one another by an intermediate layer of thin film dry solid polymer electrolyte, and electrodes connected to the outer faces of the outer semiconductor layers, one of said outer semiconductor layers adapted to receive incident light on its said outer face, said last mentioned semiconductor having a higher band gap than the adjacent semiconductor.
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Accused Products
Abstract
A double photoelectrochemical cell for converting solar energy directly to electricity. The device in one embodiment has two semiconductors which are separated from each other by a dry solid polymer electrolyte. The two semiconductors have a different band gap; for example, one is n-type CdS and the other is p-type CdTe. The polymer electrolyte, for example, is a thin film polyethylene oxide acting as a polymer matrix containing a polysulfide redox couple, for example, Na2 S4. The polymer electrolyte is transparent, insulating and capable of transporting ions. At least one of the semiconductors is semi-transparent. The short wavelengths of light are absorbed by the semi-transparent wide band gap semiconductor, and the long wavelengths pass therethrough, and through the polymer film electrolyte, and are absorbed by the narrow band gap semiconductor. The output of the cell is double; one from each semiconductor, i.e., they are series-connected. Output voltage, for example, is about 0.625 volts. The theoretical efficiencies in the example are about 35%, compared with about 25% for a standard photovoltaic cell having a single junction. Also included is a method of manufacturing such a cell.
38 Citations
14 Claims
- 1. A tandem photovoltaic device comprising a sandwich structure of at least three semiconductor layers each separated from one another by an intermediate layer of thin film dry solid polymer electrolyte, and electrodes connected to the outer faces of the outer semiconductor layers, one of said outer semiconductor layers adapted to receive incident light on its said outer face, said last mentioned semiconductor having a higher band gap than the adjacent semiconductor.
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4. A photoelectric device for converting incident electromagnetic radiation to electricity comprising a plurality of unit cells each having a transparent counter electrode, a thin film dry solid polymer electrolyte adjacent thereto, a semiconductor adjacent to said electrolyte and having a higher resistivity than said electrolyte at at least the interface;
- said units being positioned adjacent to one another, and separated by a transparent conductive layer, with the radiation passing successively through the units; and
the band gap of the semiconductors to first receive the incident radiation being greater than the band gap of the adjacent semiconductor to next receive the radiation.
- said units being positioned adjacent to one another, and separated by a transparent conductive layer, with the radiation passing successively through the units; and
- 6. A photoelectric device comprising, a transparent counter electrode, a thin film dry solid polymer electrolyte adjacent thereto, a semiconductor adjacent to said polymer electrolyte film, said semiconductor having a surface layer of higher resistivity than the electrolyte and an underlying body adjacent said surface layer and of lower resistivity than said layer.
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9. A photoelectric device comprising:
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a transparent counter electrode; a thin dry film solid polymer electrolyte adjacent thereto; a thin transparent highly conductive film adjacent said polymer; a semiconductor adjacent said highly conductive film; said thin transparent conductive film having a work function sufficient to produce a rectifying barrier with said semiconductor. - View Dependent Claims (10, 11, 12)
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Specification