Solution-phase synthesis of metal chalcogenide nanocrystals at low temperatures using dialkyl dichalcogenide precursors

Solution-phase synthetic reactions have proven to be viable routes toward semiconductor metal chalcogenide nanocrystals; however, these reactions are often reliant upon high temperatures, designer single-source precursors, or environmentally harmful reagents. To overcome these obstacles, a versatile method for the moderately low temperature synthesis of metal chalcogenide nanocrystals using dialkyl dichalcogenides as the chalcogen source has been developed. These precursors decompose in solution to promote the growth of kinetically controlled nanoscale products. Well-defined, 1-D indium sulfide (In2S3) nanorods are synthesized using di-tert-butyl disulfide as the sulfur source at 180°C. In a similar fashion, monodisperse wurtzite copper indium sulfide (wz-CuInS2) and tin sulfide (SnS) nanocubes can be synthesized by using di-tert-butyl disulfide. This method proves equally effective toward the synthesis of novel nanocrystals of tin selenide (SnSe) using di-tert-butyl diselenide and cubic indium oxide (In2O3) nanocrystals using a family of peroxides. To better understand the role of these dialkyl dichalcogenide precursors, the nanocrystal growth mechanisms have been explored for the dichalcogenide-mediated synthesis of wz-CuInS2 and c-In2O3.