US4064522A
Expired / Lapsed
US
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High efficiency selenium heterojunction solar cells
Assignee: BP Solar International LLC
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Filing: 1976-02-04
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Granted: 1977-12-20
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Expires: 1996-02-04
Abstract
Abstract A photocell includes a metallic base electrode, a continuous, crystalline P-type semiconductive selenium layer less than about 50 microns thick, a thin tellurium layer interposed therebetween to metallurgically bond the base electrode to the selenium layer and to form an ohmic contact between the base electrode and the selenium layer, a thin N-type semiconductive cadmium selenide layer contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween, a pellucid layer of at least one cadmium chalcogenide contiguous with the cadmium selenide layer and forming an ohmic contact therewith and a current collecting electrode on the cadmium chalcogenide layer. The sunlight conversion efficiency of the cell is at least about 3.0%. The efficiency can be further improved by doping the selenium layer to improve its conductivity and by providing an N-type layer of cadmium selenide and N + cadmium oxide. This can be done by continuously varying the oxygen content of the N-type layer. It is further helpful if a counterelectrode in the form of a grid is added, which minimizes both the resistance between the grid members in the cadmium layer and the blockage of light by the grid.
Inventors
- 👤 Robert F. Shaw
- 👤 Amal K. Ghosh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:58
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; H10F77/121; H10F10/00; H10F10/10; H10F10/16; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/34; H10P14/3402; H10P14/3424; H10P14/3426; H10P14/3434; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/543
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
96 words
A photovoltaic device which comprises a metallic base electrode; a continuous, crystalline P-type semiconductive selenium layer; a thin tellurium layer interposed between the base electrode and the selenium layer to provide a metallurgical bond between the base electrode and the selenium layer and to provide an ohmic contact therebetween; a thin N-type semiconductive cadmium selenide layer contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween; a pellucid layer of cadmium oxide contiguous with the cadmium selenide layer and forming an ohmic contact therebetween and a metallic current collecting electrode on the cadmium chalcogenide layer.
Claim 2
Dependent Claim
96 words
A photovoltaic device which comprises a metallic base electrode; a continuous, crystalline P-type semiconductive selenium layer; a thin tellurium layer interposed between the base electrode and the selenium layer to provide a metallurgical bond between the base electrode and the selenium layer and to provide an ohmic contact therebetween; a thin N-type semiconductive cadmium selenide layer contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween; a pellucid layer of cadmium oxide contiguous with the cadmium selenide layer and forming an ohmic contact therebetween and a metallic current collecting electrode on the cadmium chalcogenide layer.
Claim 3
Dependent Claim
30 words
The photovoltaic cell described in claim 1 wherein the P-type selenium layer is doped with at least one dopant selected from the group consisting of chlorine, tellurium, thallium and mercury.
Claim 4
Dependent Claim
21 words
The photovoltaic device described in claim 2 wherein the dopant is present in amounts less than about 20,000 parts per million.
Claim 5
Dependent Claim
19 words
The photovoltaic cell described in claim 1 wherein the P-type selenium layer is less than about 50 microns thick.
Claim 6
Dependent Claim
20 words
The photovoltaic cell described in claim 4 wherein the P-type selenium layer is between about 3 and 50 microns thick.
Claim 7
Dependent Claim
49 words
The photovoltaic cell as described in claim 1 wherein the N-type layer is a mixture of N-type cadmium selenide and N+ type cadmium oxide with the oxygen content varying from substantially zero at the P-N junction to about 50 atomic % at the outer surface of the N-type layer.
Claim 8
Dependent Claim
21 words
The photovoltaic cell as described in claim 1 wherein the N-type layer is between about 20 A and 1000 A thick.
Claim 9
Dependent Claim
156 words
A photovoltaic device which comprises a metallic base electrode, the metal being at least one metal selected from the group consisting of iron, nickel, cobalt, aluminum and alloys thereof; a continuous, crystalline P-type selenium layer less than about 50 microns thick; a tellurium layer between about 50 A and 10,000 A thick interposed between the base electrode and the selenium layer and forming an ohmic contact therebetween; an N-type cadmium selenide layer less than about 1000 A thick contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween; an N+ type cadmium oxide layer less than about 1000 A thick in ohmic contact with the cadmium selenide layer; and a metallic current collecting electrode in grid form on the cadmium oxide layer which maximizes transmission of incident light through the N+ and N-type layers to the heterojunction while minimizing the resistance between fingers of the grid whereby conversion of sunlight to electrical energy is maximized.
Claim 10
Dependent Claim
156 words
A photovoltaic device which comprises a metallic base electrode, the metal being at least one metal selected from the group consisting of iron, nickel, cobalt, aluminum and alloys thereof; a continuous, crystalline P-type selenium layer less than about 50 microns thick; a tellurium layer between about 50 A and 10,000 A thick interposed between the base electrode and the selenium layer and forming an ohmic contact therebetween; an N-type cadmium selenide layer less than about 1000 A thick contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween; an N+ type cadmium oxide layer less than about 1000 A thick in ohmic contact with the cadmium selenide layer; and a metallic current collecting electrode in grid form on the cadmium oxide layer which maximizes transmission of incident light through the N+ and N-type layers to the heterojunction while minimizing the resistance between fingers of the grid whereby conversion of sunlight to electrical energy is maximized.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-19 | 1981-06-20 | 1981-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-19 | 1985-06-20 | 1985-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-19 | 1989-06-20 | 1989-12-20 | $7700.00 | Window Closed / Lapsed |