ARTICLE pubs.acs.org/JPCC
Photoelectrochemical Properties of Fe2O3SnO2 Films Prepared by SolGel Method Hiroaki Uchiyama,* Masashi Yukizawa, and Hiromitsu Kozuka Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita, 564-8680, Japan
bS Supporting Information ABSTRACT: Fe2O3SnO2 coating films of various Sn/(Fe þ Sn) mole ratios, rSn, were prepared by dip-coating on Nesa silica glass substrates from the solutions consisting of Fe(NO3)3 3 9H2O, SnCl4 3 5H2O, H2O, CH3COCH2COCH3, and CH3OC2H4OH. The photoanodic properties were studied in a three-electrode cell with an aqueous buffer solution of pH = 7 as the supporting electrolyte. The Fe2O3SnO2 films of rSn = 00.25 comprised hematite phase and exhibited photoresponse under the UV and visible light. The photoanodic response of the RFe2O3 film was enhanced by doping with Sn4þ; the film of rSn = 0.1 exhibited the maximum IPCE (incident photon-to-current efficiency) of 26.9% and 8.6% at the wavelengths of 350 and 425 nm, respectively, which were higher than those of the Fe2O3TiO2 film of Ti/(Fe þ Ti) = 0.1 prepared by similar process. IPCE decreased with increasing rSn from 0.1 to 0.25. The films of rSn g 0.5 comprised rutile phase without hematite phase, showing very low IPCE.
1. INTRODUCTION Wet-type solar cells using semiconductor photoelectrodes have been widely investigated since the discovery of the Honda Fujishima effect in 1972.1 The photoelectrodes for the solar cells are required to have high photoelectrochemical stability in aqueous solutions and high energy conversion efficiency. Anatase-type TiO2 was first suggested as a photoanode and has good photochemical stability and high photoanodic performance. However, TiO2 has a large band gap of about 3 eV and hence is photoexcited only by UV light (
