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

CuInS2 nanoparticles were synthesized by thermal decomposition of a mixture of [Cu(SON((CNPr2)-Pr-i)(2))(2)] and [In(SON((CNPr2)-Pr-i)(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.