Phase-Selective Synthesis of CuInS 2 Nanocrystals

Single-source precursor, [(Ph3P)CuIn(SC{O}Ph)4] (1), and dual-source precursors, [Cu(SC{O}Ph)] (2) and [In(bipy)(SC{O}Ph)3] (3), have been used to obtain the monodispersed wurtzite (hexagonal) and zincblende (also called sphalerite, cubic) phases of copper indium sulfide nanocrystals (CIS NCs). The NCs have been characterized by X-ray powder diffraction patterns, transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray analysis. It is shown that the relative ratios of surfactants have influence on the formation of the wurtzite or zincblende phase of CIS. Moreover, the reaction temperature plays a role in stabilizing the high-temperature metastable zincblende cubic phase at room temperature. In the presence of trioctylphosphine oxide (TOPO) and dodecanethiol (DT), 1 generates the wurtzite phase of CIS when the reaction temperature is below 275 °C, but above this temperature the obtained product belongs to zincblende (cubic). The morphology of the CIS also changes fr...