7.2% efficient polycrystalline silicon photoelectrode

George W. Cogan, Chris M. Gronet, James F. Gibbons, Nathan S. Lewis

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


After etching, n-type cast polycrystalline silicon photoanodes immersed in a solution of methanol and a substituted ferrocene reagent exhibit photoelectrode efficiencies of 7.2%±0.7% under simulated AM2 illumination. Scanning laser spot data indicate that the grain boundaries are active; however, the semiconductor/liquid contact does not display the severe shunting effects which are observed at a polycrystalline Si/Pt Schottky barrier. Evidence for an interfacial oxide on the operating polycrystalline Si photoanode is presented. Some losses in short circuit current can be ascribed to bulk semiconductor properties; however, despite these losses, photoanodes fabricated from polycrystalline substrates exhibit efficiencies comparable to those of single crystal material. Two major conclusions of our studies are that improved photoelectrode behavior in the polycrystalline silicon/methanol system will primarily result from changes in bulk electrode properties and from grain boundary passivation, and that Fermi level pinning by surface states does not prevent the design of efficient silicon-based liquid junctions.

Original languageEnglish
Pages (from-to)539-541
Number of pages3
JournalApplied Physics Letters
Issue number5
Publication statusPublished - 1984

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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