Photocell device for evolving hydrogen and oxygen from water

• US 4,643,817 A
• Filed: 06/07/1985
• Issued: 02/17/1987
• Est. Priority Date: 06/07/1985
• Status: Expired due to Fees

• Current Assignee: Electric Power Research Institute
• Original Assignee: Electric Power Research Institute Incorporated
• Inventors: Appleby, A. John
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US06/742,476
• Time in Patent Office: 620 Days
• Field of Search: 136/249 TJ, 429/111, 204/129, 204/242, 204/278, 204/DIG. 3, 204/157.15, 204/157.40, 204/157.52
• US Class Current: 204/242
• CPC Class Codes: C25B 1/55 Photoelectrolysis
• CPC Class Codes: H01L 31/03529 Shape of the potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/0687 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• CPC Class Codes: H01L 31/076 Multiple junction or tandem solar cells
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y10S 204/03 Auxiliary internally generated electrical energy

Abstract

A photocell device for evolving hydrogen and oxygen from water using solar radiation is formed with a plurality of p-n junctions. A transparent ohmic window is disposed at the p-n junctions to avoid lattice mismatch and to provide maximized equal current densities in each layer of the plurality of p-n cells.

Claims

1. A photovoltaic assembly useful for splitting water into hydrogen and oxygen gases, comprising:

a p-I-n type photovoltaic cell having a p-type conductivity layer, an intrinsic semiconductor layer, and an n-type conductivity layer formed to provide a medium bandgap cell;

a high bandgap n-type layer disposed above said p type layer of said photovoltaic cell and adapted to contact an electrolyte including water;

a low bandgap p-type layer disposed below said n type layer of said photovoltaic cell and adapted to contact an electrolyte including water; and

transparent ohmic window layers formed between the p and n layers of said photovoltaic cell and the high bandgap and low bandgap layers.

2. A photovoltaic assembly as in claim 1, wherein said p-I-n cell is about 400 nanometers or less in thickness, and the high gap n-layer and low gap p-layer are about 100-400 nanometers in thickness.

3. A photovoltaic assembly useful for splitting water into hydrogen and oxygen gases, comprising:

a plurality of stacked p-I-n type photovoltaic cells, each cell having a p-type conductivity layer, an intrinsic semiconductor layer and an n-type semiconductor layer, wherein, the bandgap of each cell decreases from the illuminated top cell to the nonilluminated lowest cell and wherein adjacent cells are ohmically interconnected in series by means of a transparent conductive layer and the uppermost p type layer and the lowermost n type layer are adapted to contact an electrolyte including water.

4. A photovoltaic cell assembly useful for splitting water into hydrogen and oxygen gases comprising:

a spherical type structure having a plurality of concentric n-p or p-n type layer pairs in that order; and

a transparent ohmic window formed at the junction between adjacent n-p or p-n layer pairs.

5. A photovoltaic cell assembly useful for splitting water into hydrogen and oxygen gases, comprising:

a photovoltaic cell having at least two p-n type conductivity semiconductor layer pairs formed in a concentric spherical type configuration, the n-type layer of one of said pairs being at the center of said spherical type configuration; and

transparent ohmic windows formed in each p-n layer pair of said cell between the p and n conductivity type layers of each said pair.