Facile synthesis of NiSe2:α-Fe2O3 thin film: Physical, optical and photoelectronic properties

In this study, a highly scalable approach to fabricating NiSe2:α-Fe2O3 heterojunction thin film in the absence of a dehydration step or lattice parameter matching was established. The attachment of NiSe2 to α-Fe2O3 leads to an 82% and 97% decrease in charge transfer resistance (with and without illumination respectively) compared to pristine α-Fe2O3. The magnitude of the open circuit potential increased from approximately -0.30 V to -0.42 V vs Ag/AgCl, providing a stronger electric field for charge carrier separation. Charge transfer efficiency was calculated by using a ratio of charge carriers removed and those produced in the bulk. Scanning electron microscopy coupled with the electrodeposition current-time transients study proved that the attachment process involved the progressive nucleation of NiSe2 and the simultaneous cathodic reduction of α-Fe2O3.