Examining the potential of BiCuSeO thin films for photoelectrochemical water splitting

Photoelectrochemical cells with semiconductor photoelectrodes for water splitting have attracted increased interest in the field of solar energy, which requires suitable photoelectrode materials with excellent electrical properties and a visible light response. In this article, BiCuSeO thin films were obtained by evaporating CuBi precursors followed by a selenization treatment. The annealing temperatures (350 - 475°C) and oxygen concentrations (0 - 33%) were optimized to obtain high-quality thin films. A great number of thin flakes were found on the surface of the optimized films, which could benefit the catalyst application. The optical absorption measurement indicated a high absorption coefficient for BiCuSeO thin films in the 300 nm to 700 nm range. Photoelectrochemical analyses of BiCuSeO thin films showed that a large photocurrent density of 10 mA/cm² was achieved at a relatively low bias, −0.55 V, versus reversible hydrogen electrode, significant for a strong photoresponse for BiCuSeO thin films exhibiting flakes on the surface. These results indicate that BiCuSeO is a potential material for photocatalyst applications.