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H_(2) evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover.

Published

Author(s)

Daniel V. Esposito, Igor Levin, Thomas P. Moffat, Albert A. Talin

Abstract

Photoelectrochemical (PEC) water splitting represents a promising route for renewable production of hydrogen, but trade-offs between photoelectrode stability and efficiency have greatly limited the performance of PEC devices. In this work, we employ a metal–insulator–semiconductor (MIS) photoelectrode architecture that allows for stable and efficient water splitting using narrowbandgap semiconductors. Substantial improvement in the performance of Si-based MIS photocathodes is demonstrated through a combination of a high-quality thermal SiO_(2) layer and the use of bilayer metal catalysts. Scanning probe techniques were used to simultaneously map the photovoltaic and catalytic properties of the MIS surface and reveal the spillover-assisted evolution of hydrogen off the SiO_(2) surface and lateral photovoltage driven minority carrier transport over distances that can exceed 2 cm. The latter finding is explained by the photo- and electrolyte-induced formation of an inversion channel immediately beneath the SiO_(2)/Si interface. These findings have important implications for further development of MIS photoelectrodes and offer the possibility of highly efficient PEC water splitting.
Citation
Nature Materials
Issue
3626

Keywords

Hydrogen spillover, photoelectrochemicals cells, water splitting, MOS photoelectrodes, scanning electrochemical microscopy, laser beam induced current (LBIC)

Citation

Esposito, D. , Levin, I. , Moffat, T. and Talin, A. (2013), H_(2) evolution at Si-based metal-insulator-semiconductor photoelectrodes enhanced by inversion channel charge collection and H spillover., Nature Materials, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=912894 (Accessed February 22, 2024)
Created May 5, 2013, Updated February 19, 2017