Browse Prior Art Database

Optical Multipass Structure for Photolysis of Water

IP.com Disclosure Number: IPCOM000087205D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+4]

Abstract

Very thin layers of photoactive materials are required to produce charge transfer during photolysis, i.e., photodecomposition of H(2)O into H(2) and O(2). However, these thin layers have not absorbed all of the incident radiation [1].

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Optical Multipass Structure for Photolysis of Water

Very thin layers of photoactive materials are required to produce charge transfer during photolysis, i.e., photodecomposition of H(2)O into H(2) and O(2). However, these thin layers have not absorbed all of the incident radiation [1].

An efficient electrode structure is described for the photodecomposition of water. It utilizes a tungsten dendritic structure [2] which is overcoated with a very thin photoactive material. Enhanced light absorption by the very thin photoactive material is due to multiple optical passes inherent in the dendritic structure.

This structure, which is shown schematically in the drawing, allows the use of a very thin photoactive layer, which can improve the charge transfer characteristic in addition to the enhanced optical absorption. In order to transfer charge efficiently from a photoactive material to decompose water into hydrogen and oxygen, it is necessary to impose a large electric field across the material. This field sweeps holes to the surface where they combine with OH/-/ ions to produce O(2) and sweeps electrons to the other electrode (usually Pt) where they combine with H/+/ ions to give H(2). The thinner the layer the higher the field (or band bending per unit thickness of material). However, on a flat plate structure very thin layers can lead to low conversion efficiencies due to the lack of complete light absorption. Thus, by using a thin layer in conjunction with the dend...