Photoluminescence and Characterization of ZnO/Zn2SnO4 Nanocables

ZnO and Zn2SnO4 are excellent functional semiconducting materials with wide direct band gap, high electron mobility and photocatalytic activity. High―density single―crystalline ZnO/Zn2SnO4 nanocables were successfully synthesized by using a simple thermal co―evaporation from a mixture source of ZnO and SnO2 powders. The products in general contain various geometries of wires, with an average diameter of 50―100 nm. These nanowires are consisted of ZnO core and Zn2SnO4 sheath with ultra―length, up to several hundred microns. The images of transmission electron microscope (TEM) show that the ZnO core of the nanocable grows along the direction of <0001>. The interface between ZnO and Zn2SnO4 performs lattice coherent. The photoluminescence (PL) spectra recorded from the nanocables at room temperature show only a strong peak corresponding to UV band emission of ZnO at about 380.58 nm, which indicates that the sheath of Zn2SnO4 prohibits the oxygen deficiency in the surface of nanocables. ZnO/Zn2SnO4 nanocables can effectively suppress the recombination of the photogenerated electrons and holes, which is promising as anode for dye―sensitized solar cells.