iso-Propylthiobiuret-copper and indium complexes as novel precursors for colloidal synthesis of CuInS2 nanoparticles

Abstract

CuInS₂ nanoparticles were synthesized by thermal decomposition of a mixture of [Cu(SON(CNⁱPr₂)₂)₂] and [In(SON(CNⁱPr₂)₂)₃] in oleylamine and/or dodecanethiol. X-ray diffraction showed that chalcopyrite (tetragonal) CuInS₂, wurtzitic (hexagonal) CuInS₂, or chalcopyrite with minor amount of wurtzitic phases could be obtained by varying the reaction conditions. Changing the reaction conditions could also control the morphology of the CuInS₂ nanoparticles (spherical, hexagonal, trigonal or conical). Luminescent CuInS₂ nanoparticles were obtained only in the absence of oleylamine. Wurtzite-chalcopyrite polytypism was observed in one of the samples by high-resolution transmission electron microscopy.