Steven A Kaiser

US Patent:

44143001, Nov 8, 1983

Filed:

Mar 29, 1977

Appl. No.:

5/782596

Inventors:

Mark S. Wrighton - Medford MA
Arthur B. Ellis - Brookline MA
Steven W. Kaiser - South Charleston WV

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H01M 636

US Classification:

429111

Abstract:

Sustained conversion of low energy visible or near i. r. light (>1. 25 eV) to electrical energy has been obtained using wet photoelectrochemical cells where there are no net chemical changes in the system. Stabilization of n-type semi-conductor anodes of CdS, CdSe, CdTe, GaP, GaAs and InP to photoanodic dissolution is achieved by employing selected alkaline solutions of Na. sub. 2 S, Na. sub. 2 S/S, Na. sub. 2 Se, Na. sub. 2 Se/Se, Na. sub. 2 Te and Na. sub. 2 Te/Te as the electrolyte. The oxidation of (poly) sulfide, (poly)selenide or (poly)telluride species occurs at the irradiated anode, and reduction of polysulfide, polyselenide or polytelluride species occurs at the dark Pt cathode of the photoelectrochemical cell. Optical to electrical energy conversion efficiencies approaching 15% at selected frequencies have been observed in some cells. The wavelength for the onset of photocurrent corresponds to the band gap of the particular anode material used in the cell.