Nanostructural Tin-Based Semiconductor Oxides:Synthesis And Applications

The main contents of the present work are as follows: Nanostructural tin-basedsemiconductor oxides were successfully synthesized by the hydrothermal route. The obtainedproducts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM)and transmission electron microscope (TEM) measurements. Based on the experimentalresults, possible mechanisms for the formation of the nanostructural tin-based oxides wereproposed. Furthermore, these nanostructured oxides were used as the electrode materials forLi-ion batteries (LIB) and dye-sensitized solar cells (DSSCs), and the relationships between thenanostructured electrode materials and the photovoltaic performances were also investigated.(i) SnO2hollow spheres covered by nanorods have been synthesized by using SnSO4asprecursor in the absence of template. XRD and TEM characterizations reveal that thesesynthesized SnO2are hollow spheres and their diameter is found to be ca.50-200nm. Thenanorods covered on the external surfaces of hollow spheres are found to be ca.5nm indiameter and50nm in length. Based on the experimental results, anoxidizing-aggregating-Ostwald ripening model has been proposed for the formation of the SnO2nanostructural hollow spheres covered by nanorods. The pH value of the reaction system hasa close impact on the formation of those unique SnO2hollow spheres.(ii) By using a hydrothermal route, highly crystalline ZTO polyhedrons have been preparedunder the different reaction conditions. It was found that the reaction conditions, such as pHvalue, reaction time influenced significantly the growth of ZTO crystals. On the basis ofexperimental results, a possible growth mechanism of ZTO crystals was proposed.Furthermore, single crystalline ZTO polyhedrons with monodispersity were prepared accordingto the proposed mechanism.(iii) SnO2hollow spheres covered by nanorods were used as the anode materials in Li-ionbatteries, and exhibited an initial capacity of2176mAhg-1. After30cycles, the capacityremained550mAhg-1. Furthermore, ZTO nanocrystals were applied in dye-sensitized solarcell, and an efficiency of2.67%was obtained using organic dye D131dye as a sensitizer.