Cu2ZnSnS4-Ag2S nanoscale p-n heterostructures as sensitizers for photoelectrochemical water splitting

A cation exchange-based route was used to produce Cu2ZnSnS4 (CZTS)–Ag2S nanoparticles with controlled composition. We report a detailed study of the formation of such CZTS–Ag2S nanoheterostructures and of their photocatalytic properties. When compared to pure CZTS, the use of nanoscale p–n heterostructures as light absorbers for photocatalytic water splitting provides superior photocurrents. We associate this experimental fact to a higher separation efficiency of the photogenerated electron–hole pairs. We believe this and other type-II nanoheterostructures will open the door to the use of CZTS, with excellent light absorption properties and made of abundant and environmental friendly elements, to the field of photocatalysis.