Water-induced structure phase transition of CdSe nanocrystals in composite hydroxide melts

Single-crystalline CdSe nanostructures have been synthesized for the first time by the composite-hydroxide-mediated approach with a small amount of water. The phase transition of CdSe nanocrystals from zinc blende to wurtzite phase can be controlled by varying the water content and the morphologies of the CdSe nanocrystals are controlled simultaneously. The phase transition and morphology have been characterized by XRD, SEM and TEM. The phase transition critical points with respect to proper water content have been found at different temperatures. The phase transition and growth mechanism have been discussed. Optical band gaps of these two CdSe nanostructures have been investigated by an UV–vis spectrophotometer.