Light-induced cleaning of CdS and ZnS nanoparticles: superiority to annealing as a post-synthetic treatment of functional nanoparticles

Abstract

The generation of clean CdS nanoparticles from as-synthesized ones was examined using visible light. Irradiating visible light onto the nanoparticles removes organic impurities from the synthesis of CdS, while preserving the crystalline phase and nanoscale structure of the as-synthesized semiconductor as well as creating mesopores. Compared with conventional thermal annealing, which causes oxidation and sintering of nanoparticles, the indigenous light-induced cleaning provides a better post-treatment procedure for photoactive semiconductor nanoparticles. A similar feature was also observed for the ZnS nanoparticle system. The water reduction activity (lambda >= 420 nm) of light-treated CdS was 5 times higher than that of annealed CdS.