Photoelectrochemical Characterization of Sprayedα-Fe2O3Thin Films: Influence of Si Doping andSnO2Interfacial Layer

α-Fe2O3thin film photoanodes for solar water splitting were prepared by spray pyrolysis ofFe(AcAc)3. The donor density in theFe2O3films could be tuned between1017–1020 cm-3by doping with silicon. By depositing a 5 nmSnO2interfacial layer between theFe2O3films and the transparent conducting substrates, both the reproducibility and the photocurrent can be enhanced. The effects of Si doping and the presence of theSnO2interfacial layer were systematically studied. The highest photoresponse is obtained forFe2O3doped with 0.2% Si, resulting in a photocurrent of 0.37 mA/cm2at 1.23 VRHEin a 1.0 M KOH solution under 80 mW/cm2AM1.5 illumination.