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US4649227A
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Photoactive pyrite layer and process for making and using same
Assignee: Hahn Meitner Institut Berlin GmbH
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Filing: 1985-07-24
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Granted: 1987-03-10
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Expires: 2005-07-24
Abstract
Abstract Photoactive pyrite layers, whose preparation and use represent a commercially highly interesting alternative to materials hitherto in common use. The semiconductor material chiefly used until now, e.g. for solar cells, is silicon. However, its costs of manufacture are too high to allow solar cells to be made at favorable cost. The significance of the disclosure and development of pyrite as a semiconductor material, especially for solar cells, lies in the fact that it is plentifully occurring and cheap, as well as environmentally compatible. Pyrite (iron pyrites, FeS 2 ) can be used as a photoactive material in solar cells and in optoelectronic components. It is possible to use both naturally occurring pyrite, after a material treatment to improve the photosensitivity, as well as synthetically produced, single-crystal and polycrystalline pyrite.
Inventors
- 👤 Helmut Tributsch
- 👤 Ahmed Ennaoui
- 👤 Wolfram Jaegermann
- 👤 Sebastian Fiechter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:57
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; C; C30; C30B; C30B25/00; C30B29/00; C30B29/10; C30B29/46; Y; Y02; Y02E; Y02E10/00; Y02E10/50
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
57 words
A photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, with a concentration of other impurities of less than 10 20 per cm 3 .
Claim 2
Dependent Claim
57 words
A photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, with a concentration of other impurities of less than 10 20 per cm 3 .
Claim 3
Dependent Claim
66 words
A photoactive structure according to claim 1, wherein the body of pyrite is doped so as to have an effective charge carrier density of more than 10 15 per cm 3 , a derived charge carrier mobility of about 200 cm 2 /Vs, a conversion yield of at least 1%, a quantum yield of up to about 90% and a photovoltage of more than 0.25 V.
Claim 4
Dependent Claim
110 words
A process of making a photoactive structure comprising a layer of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, with a concentration of other impurities of less than 10 20 per cm 3 , the process comprising subjecting naturally occurring pyrite to a thermochemical treatment for improving the desired crystallinity, purity, and stoichiometry of the pyrite material, and subjecting the layer of heat treated pyrite material to a selected etching, immersion, or anodic polarization surface treatment for improving the photosensitivity of the layer.
Claim 5
Dependent Claim
110 words
A process of making a photoactive structure comprising a layer of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, with a concentration of other impurities of less than 10 20 per cm 3 , the process comprising subjecting naturally occurring pyrite to a thermochemical treatment for improving the desired crystallinity, purity, and stoichiometry of the pyrite material, and subjecting the layer of heat treated pyrite material to a selected etching, immersion, or anodic polarization surface treatment for improving the photosensitivity of the layer.
Claim 6
Dependent Claim
32 words
A process according to claim 3, wherein the pyrite material is originally in the form of a block, and including cutting of thin layers from the block to form a photoactive layer.
Claim 7
Dependent Claim
30 words
A process according to claim 3, wherein the naturally occurring pyrite material is originally in the form of powder and the layer of pyrite material is produced by chemical transport.
Claim 8
Dependent Claim
28 words
A process according to claim 3, wherein the thermal treatment is carried out in an evacuated vessel at about 500° C. over a period of about one week.
Claim 9
Dependent Claim
65 words
A process according to claim 3, including polishing the pyrite layer and etching the polished pyrite layer using wet chemical means in a first step for about 30 to 60 seconds with a concentrated solution of HF/CH 3 COOH/HNO 3 in the proportions of 1:1:2, and then with H 2 O 2 (30%)/H 2 SO 4 (95%) in the proportion of 1:1 under anodic polarization.
Claim 10
Dependent Claim
36 words
A process according to claim 7, including using the pyrite layer as an electrode in a photoelectrochemical solar cell with an aqueous solution of 4M HI, 0.05M I 2 and 1M CaI 2 as an electrolyte.
Claim 11
Dependent Claim
72 words
A process of making a photoactive structure comprising producing a pyrite material synthetically by reaction between either iron or iron containing compounds, and either sulfur or sulfur containing compounds, forming the produced pyrite material into either thin layers or crystalline bodies by crystal growth from which slices of pyrite material can be cut and further surface treating the slices of material by etching, immersion, or anodic polarization to improve the photosensitivity thereof.
Claim 12
Dependent Claim
72 words
A process of making a photoactive structure comprising producing a pyrite material synthetically by reaction between either iron or iron containing compounds, and either sulfur or sulfur containing compounds, forming the produced pyrite material into either thin layers or crystalline bodies by crystal growth from which slices of pyrite material can be cut and further surface treating the slices of material by etching, immersion, or anodic polarization to improve the photosensitivity thereof.
Claim 13
Dependent Claim
139 words
A process according to claim 9, including melting high purity sulfur under high vacuum for about 30 minutes, cooling the melted sulfur while maintaining a vacuum, manipulating the cooled sulfur under a protective gas for the purpose of removing material, heating high purity iron in the form of either a powder or foil to about 800° C. under a stream of dry H 2 /Ar gas mixture for about two hours to reduce the surface of the high purity iron, mixing stoichiometric quantities of the iron and sulfur together in an evacuated, sealed vessel at about 650° C. to react the iron and sulfur, continuing the reaction for about 100 hours with the addition of small amounts of halogen and in the presence of small amounts of excess sulfur to avoid thermal dissociation of pyrite into pyrrhotite and sulfur.
Claim 14
Dependent Claim
120 words
A process according to claim 9, wherein powdered pyrite and arsenic are placed at one location in a vessel, subjecting the vessel to high vacuum, adding bromine to the vessel and sealing the vessel, heating the vessel to 800° C. at the location where the powdered pyrite and arsenic are placed, a temperature of 550° C. being maintained at another location in the vessel so that over a period of about ten days pyrrhotite crystals are formed in a thin layer of decomposition of the pyrite powder and by local transport with the bromine, and reversing the temperature gradient in the vessel to reform the thin layer of pyrrhotite crystals during about ten more days into statistically oriented pyrite crystals.
Claim 15
Dependent Claim
32 words
A process according to claim 9, wherein the crystal growth of pyrite is carried out by way of gas transport reactions with either a halogen or interhalogen compound as the transport agent.
Claim 16
Dependent Claim
38 words
A process according to claim 9, wherein the pyrite is deposited as a thin layer from the gas phase by thermal decomposition and reaction of either iron carbonyls or iron halides, with either sulfur or hydrogen sulfide gas.
Claim 17
Independent Claim
103 words
A method of using as a solar cell electrode in a circuit, a photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, wherein x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, and a concentration of other impurities of less than 10 20 per cm 3 , the method comprising subjecting the body of pyrite material in the form of a solar cell electrode in a circuit to illumunation by light to convert the light to electrical energy in the circuit.
Claim 18
Independent Claim
103 words
A method of using as a solar cell electrode in a circuit, a photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, wherein x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, and a concentration of other impurities of less than 10 20 per cm 3 , the method comprising subjecting the body of pyrite material in the form of a solar cell electrode in a circuit to illumunation by light to convert the light to electrical energy in the circuit.
Claim 19
Independent Claim
95 words
A method of using as an opto-electronic component in a circuit, a photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, and a concentration of other impurities of less than 10 20 per cm 3 , the method comprising subjecting the body of pyrite material in the form of an opto-electronic component in a circuit to light pulses to obtain electrical signal responses.
Claim 20
Independent Claim
95 words
A method of using as an opto-electronic component in a circuit, a photoactive structure comprising a body of pyrite material having the formula FeS 2 ±x, where x is ≦0.05, a doping of from 10 16 to 10 19 per cm 3 selected from the group consisting of manganese, arsenic, cobalt, and chloride, and a concentration of other impurities of less than 10 20 per cm 3 , the method comprising subjecting the body of pyrite material in the form of an opto-electronic component in a circuit to light pulses to obtain electrical signal responses.
Claim 21
Dependent Claim
23 words
A method of claim 15, wherein said body is subjected to laser light pulses and the responses are measured as light-induced microwave absorption.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |