1. | Bozheyev F.♦, Akinoglu E.M.♦, Wu L.♦, Lu H.♦, Nemkayeva R.♦, Xue Y.♦, Jin M.♦, Giersig M.♦, Band gap optimization of tin tungstate thin filmsfor solar water oxidation, International Journal of Hydrogen Energy, ISSN: 0360-3199, DOI: 10.1016/j.ijhydene.2020.01.126, Vol.45, No.15, pp.8676-8685, 2020Abstract:Semiconducting ternary metal oxide thin films exhibit a promising application for solarenergy conversion. However, the efficiency of the conversion is still limited by a band gapof a emiconductor, which determines an obtainable internal photovoltage for solar watersplitting. In this report the tunability of the tin tungstate band gap by O2 partial pressurecontrol in the magnetron co-sputtering process is shown. A deficiency in the Sn concentration increases the optical band gap of tin ungstate thin films. The optimum band gap of 1.7 eV for tin tungstate films is achieved for a Sn to W ratio at unity, which establishes thehighest photoelectrochemical activity. In particular, a maximum photocurrent density of 0.375 mA cm^2 at 1.23 VRHE and the lowest reported onset potential of -0.24 VRHE for SnWO4 thin films without any co-catalyst are achieved. Finally, we demonstrate that a Ni protection layer on the SnWO4 thin film enhances the photoelectrochemical stability, which isof paramount importance for application. Keywords:thin film, tin tungstate, reactive magnetron sputtering, photocurrent density, thickness band gap Affiliations:Bozheyev F. | - | other affiliation | Akinoglu E.M. | - | University of Melbourne (AU) | Wu L. | - | other affiliation | Lu H. | - | South China Normal Universit (CN) | Nemkayeva R. | - | other affiliation | Xue Y. | - | South China Normal Universit (CN) | Jin M. | - | South China Normal Universit (CN) | Giersig M. | - | other affiliation |
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