Controllable electronic energy structure of size-controlled Cu2ZnSnS4 nanoparticles prepared by a solution-based approach.

Cu2ZnSnS4 nanoparticles with sizes of 2-5 nm, synthesized in hot organic solutions, exhibited size-dependent photoelectrochemical properties due to the quantum size effect. The potentials of the valence band edge and conduction band edge of the nanoparticles, experimentally determined by photoelectrochemical measurements, were shifted more positively and more negatively, respectively, with a decrease in particle size.