Switched Photocurrent on Tin Sulfide-Based Nanoplate Photoelectrodes

A new type of SnS₂ nanoplate photoelectrode is prepared by using a mild wet-chemical method. Depending on the calcination temperatures, SnS₂ -based photoelectrodes can either retain their n-type nature with greatly enhanced anodic photocurrent density (ca. 1.2 mA cm^-2 at 0.8 V vs. Ag/AgCl) or be completely converted into p-type SnS to generate approximately 0.26 mA cm^-2 cathodic photocurrent density at -0.8 V vs. Ag/AgCl. The dominance of sulfur and tin vacancies are found to account for the dramatically different photoelectrochemical behaviors of n-type SnS₂ and p-type SnS photoelectrodes. In addition, the band structures of n-type SnS₂ and p-type SnS photoelectrodes are also deduced, which may provide an effective strategy for developing SnS₂ /SnS films with controllable energy-band levels through a simple calcination treatment.