Controllable Synthesis Of Metal Sulfide Nanomaterials Via A Two-phase Approach

Metal sulfide semiconductor nanomaterials have attracted great interest due to the applications in optoelectronic devices, solar cells, biological labeling and photo catalysis. For further study of physical and chemical properties, developing new metal sulfide nanomaterials systematically has great meaning. It’s significant to develop a simple, controllable and environment-friendly method for nanomaterials applications. The two-phase synthetic method is a powerful strategy for preparing different semiconductor nanocrystals due to its generality and practicability. The work is focused on the investigation of the synthesis of copper-based semiconductor nano materials via two-phase interface method. The main contents as followed:(1) Copper sulfide (Cu31S16) nanocrystals have been synthesized via a two-phase approach, in which pure DDT or DDT in toluene was selected as the organic phase, and different metal salts in water are used as the aqueous phase. DDT served as caping agents, sulfide sources and reducer at the same time. The competition between DDT and hydroxylion is a important factor. The nucleation and growth process can be controlled through the reactivity of metal sources and the dosage of DDT at the water/oil interface.This two-phase approach has also been extended to prepare Ag2S and Ni9S8 nanocrystals, which may shed light on the design and synthesis of metal sulfide nanocrystals.(2)Two different-shaped Cu31S16-metal sulfide (ZnS and CdS) heteronanostructures(HNS) have been synthesized via a two-phase approach. The shape(short-matchstick, mushroom-like and ice-cream like) of Cu31S16-ZnS HNS can be effectively tailored by varying the molar ratio of the Cu/Zn precursors and the anions in the Zn sources. The drift speed of zinc ions to the water/oil interface is of great importance for the nucleation and growth which caused the change of Cu31S16-ZnS HNS in shape and structure. With an reducing of the Cu/Cd ratio, the highly fluidic nature of the Cu ions enables the saturated Cd ions to self-nucleate to form a CdS phase, followed by the doping of Cu ions into the CdS host.(3)Several different Cu31S16-CuInS2 HNS have been synthesized via a two-phase approach. The shape and structure of HNS can be controlled by varying the type of anion ions,the molar ratio of the Cu/In precursors,the Cu sources, In sources and times.