Fe-Ion-Catalyzed Synthesis of CdSe/Cu Core/Shell Nanowires.

CdSe/Cu core/shell nanowires (NWs) are successfully synthesized by a wet chemical method for the first time. By utilizing the solution-liquid-solid (SLS) mechanism, CdSe NWs are fabricated by Bi seeds, which act as catalysts. In the subsequent radial overcoating of the Cu shell on the CdSe NWs, Fe ions have been proven to be an indispensable and efficient catalyzer. The thickness of the Cu shell could be well controlled in the range of 3 to 6 nm by varying the growth temperature (from 300 to 360 °C). Our synthetic strategy pioneers a new possibility for the controlled synthesis of semiconductor-metal heterostructure NWs (especially for II-VI semiconductors), such as CdS/Cu, ZnS/Au, and ZnO/Ag, which had broad application prospects in photoconductors, thin-film transistors, and light-emitting diodes. Theoretically, electrons flow from a higher Fermi-level material to the bottom Fermi-level at the metal-semiconductor heterojunction interface, which aligns the Fermi level and establishes the Schottky barrier. It leads to excess negative charges in metals and excess positive charges in semiconductors. Therefore, those effective electron traps reduce the probability of photogenerated electron-hole pair recombination efficiently, which has been widely applied in solar cells, sensors, photocatalysis, and energy storage. The breakthrough and innovation of this synthesis method have opened up a new synthetic route with a mild reaction environment, low energy consumption, and convenience.