US4764439A
Expired / Lapsed
US
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Photoelectrochemical cell
Assignee: Sera Solar Corp
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Filing: 1984-07-05
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Granted: 1988-08-16
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Expires: 2004-07-05
Abstract
Abstract A method for converting solar energy to electricity is provided using solid-liquid interface photoelectrochemical cells wherein the liquid phase comprises a nonaqueous solvent, an electrolyte dissolved therein forming an ionically conductive solution and a redox couple suitable to accept and donate electrons from and to the electrodes. The redox couple is present in an amount sufficient to sustain a predetermined current and the concentrations of the electrolyte and redox couple in the solution are sufficient to provide no greater than a selected small voltage drop relative to the output voltage of the cell. The efficiency of conversion of light to electrical energy of such photoelectrochemical cells is 10% and greater.
Inventors
- 👤 James F. Gibbons
- 👤 George W. Cogan
- 👤 Christian M. Gronet
- 👤 Nathan S. Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:38
CPC Classifications
H; H01; H01G; H01G9/00; H01G9/20; H01M; H01M14/00; H01M14/005
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
137 words
A method for converting solar energy to electrical energy, comprising the step of exposing to solar radiation a cell comprising a semiconductor photoactive electrode, a nonaqueous solvent and an electrolyte dissolved therein forming an ionically conductive solution, a counterelectrode providing an electrical connection from said solution to said photoactive electrode; and a redox couple dissolved in said solvent suitable to accept and donate electrons from and to said electrodes upon incidence upon said cell by an external source of light, said redox couple present in an amount sufficient to sustain a predetermined current; wherein the concentrations of said electrolyte and said redox couple in said solution are selected to provide no greater than a predetermined small voltage drop in comparison to the output voltage of said cell during conversion in said cell of said light to electricity.
Claim 2
Independent Claim
137 words
A method for converting solar energy to electrical energy, comprising the step of exposing to solar radiation a cell comprising a semiconductor photoactive electrode, a nonaqueous solvent and an electrolyte dissolved therein forming an ionically conductive solution, a counterelectrode providing an electrical connection from said solution to said photoactive electrode; and a redox couple dissolved in said solvent suitable to accept and donate electrons from and to said electrodes upon incidence upon said cell by an external source of light, said redox couple present in an amount sufficient to sustain a predetermined current; wherein the concentrations of said electrolyte and said redox couple in said solution are selected to provide no greater than a predetermined small voltage drop in comparison to the output voltage of said cell during conversion in said cell of said light to electricity.
Claim 3
Dependent Claim
34 words
A method according to claim 1 wherein said solvent further comprises an agent which induces formation of a predetermined amount of an insulating compound at the interface of said semiconductor electrode and said solution.
Claim 4
Dependent Claim
16 words
A method according to claim 2 wherein said agent is water and said semiconductor comprises silicon.
Claim 5
Dependent Claim
13 words
A method according to claim 1 wherein said semiconductor conductor is an n-type.
Claim 6
Dependent Claim
12 words
A method according to claim 1 wherein said semiconductor is a p-type.
Claim 7
Independent Claim
22 words
A method according to claims 4 or 5 wherein said solution is a liquid film of a thickness less than 100 microns.
Claim 8
Independent Claim
24 words
A method according to claims 4 or 5 wherein the band gap of said semiconductor is in the range of 1.0 to 2.3 eV.
Claim 9
Dependent Claim
31 words
A method according to claim 7 wherein said semiconductor is selected from the group consisting of silicon, gallium arsenide, gallium arsenide phosphide, cadmium telluride, cadmium selenide, indium phosphide, and a-Si:H alloy.
Claim 10
Dependent Claim
27 words
A method according to claim 8 wherein said semiconductor is selected from silicon, GaAs and GaAs x P 1-x , wherein x is between 0.0 and 1.
Claim 11
Dependent Claim
12 words
A method according to claim 8 wherein said semiconductor comprises cadnium telluride.
Claim 12
Dependent Claim
13 words
A method according to claim 4 or 5 wherein said semiconductor is amorphous.
Claim 13
Dependent Claim
11 words
A method according to claim 5 wherein said semiconductor comprises p-silicon.
Claim 14
Dependent Claim
26 words
A method according to claim 1 wherein said nonaqueous solvent is characterized by a dielectric constant greater than 20 and a viscosity less than 2 centipoise.
Claim 15
Dependent Claim
28 words
A method according to claim 13 wherein said solvent is selected from an alkanol of 1 to 10 carbon atoms or nitrile of 2 to 10 carbon atoms.
Claim 16
Dependent Claim
15 words
A method according to claim 14 wherein said solvent is selected from methanol or acetonitrile.
Claim 17
Dependent Claim
19 words
A method according to claim 13 wherein said electrolyte is selected from lithium perchlorate and tetra alkyl ammonium borontetrafluoride.
Claim 18
Dependent Claim
18 words
A method according to claim 1 wherein said redox couple is selected from ferrocene-ferrocenium salts and derivatives thereof.
Claim 19
Independent Claim
35 words
A method according to claims 4, 16, 15 or 17 wherein said electrolyte is lithium perchlorate, said solvent is methanol, said redox couple is (1-hydroxyethyl) ferrocene/ (1-hydroxyethyl) ferrocenium salt, and said semiconductor is n-type silicon.
Claim 20
Independent Claim
45 words
A method according to claims 4, 16, 15 or 17 wherein said electrolyte is tetraethyl ammonium borotetrafluoride, said solvent is acetonitrile, said redox couple is ferrocene/ferrocenium salt and said semiconductor is an epitaxial layer of GaAs 0 .72 P 0 .28 on a GaAs substrate.
Claim 21
Independent Claim
31 words
A method according to claims 4, 16, 15 or 17 wherein said solvent is acetonitrile, said redox couple is ferrocene/ferrocenium salt, said electrolyte is tetraethyl ammonium borontetrafluoride and said semiconductor n-GaAs.
Claim 22
Dependent Claim
20 words
A method according to claim 1 wherein the selected small voltage drop is less than 10% of the output voltage.
Claim 23
Dependent Claim
32 words
A method according to claim 1 wherein the predetermined current is the solar photon flux with energies greater than the bandgap of the photoactive electrode multiplied by the charge of an electron.
Claim 24
Dependent Claim
163 words
A photoelectrochemical cell having improved solar to electrical energy efficiency in the range of 10% and above, comprising a semiconductor photoactive electrode, a nonaqueous solvent and an electrolyte dissolved therein forming a ionically conductive solution, a counterelectrode providing an electrical connection from said solution to said photoactive electrode; and a redox couple dissolved in said solvent suitable to accept and donate electrons from and to said electrodes upon incidence upon said cell by an external source of light, said redox couple present in an amount sufficient to sustain a predetermined current; wherein the concentrations of said electrolyte and said redox couple in said solution are selected to provide no greater than a predetermined small voltage drop in comparison to the output voltage of said cell during conversion in said cell of said light to electricity, and wherein said solvent comprises a mixture of alkylene carbonate and an alcohol of 1-10 carbon atoms and said redox couple is a ferrocene-ferrocenium salt or derivative thereof.
Claim 25
Dependent Claim
163 words
A photoelectrochemical cell having improved solar to electrical energy efficiency in the range of 10% and above, comprising a semiconductor photoactive electrode, a nonaqueous solvent and an electrolyte dissolved therein forming a ionically conductive solution, a counterelectrode providing an electrical connection from said solution to said photoactive electrode; and a redox couple dissolved in said solvent suitable to accept and donate electrons from and to said electrodes upon incidence upon said cell by an external source of light, said redox couple present in an amount sufficient to sustain a predetermined current; wherein the concentrations of said electrolyte and said redox couple in said solution are selected to provide no greater than a predetermined small voltage drop in comparison to the output voltage of said cell during conversion in said cell of said light to electricity, and wherein said solvent comprises a mixture of alkylene carbonate and an alcohol of 1-10 carbon atoms and said redox couple is a ferrocene-ferrocenium salt or derivative thereof.
Claim 26
Dependent Claim
12 words
A cell according to claim 23 wherein said solvent comprises propylene carbonate.
Claim 27
Dependent Claim
13 words
A cell according to claim 24 wherein said redox couple comprises dimethylferrocene-dimethylferrocenium salt.
Claim 28
Dependent Claim
24 words
A cell according to claim 25 wherein said solvent comprises an alcohol selected from the group consisting of n-octanol, n-hexanol, n-butanol, trifluoroethanol, and methanol.
Claim 29
Dependent Claim
11 words
A cell according to claim 26 wherein said alcohol is methanol.
Claim 30
Dependent Claim
11 words
A cell according to claim 26 wherein said alcohol is n-octanol.
References Cited (Backward Citations)
US4459343A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
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