Preparation And Characterization Of Metal-Oxide Semicomductor Nanomaterials

ZnO and SnO2, as a semiconductor material, are widely applied in many fields. Recently, their application is extended further due to some special characteristics as the size of the prepared material is decreased to nanoscale. Much attention has been paid to this area in the world. In this thesis, nanoporous ZnO crystalline thin films, nanoporous SnO2 thin films and crystalline SnO2 nanobelts were prepared by electrochemical deposition and water assisted vapor deposition technique. Their applications on dye sensitized solar cell, electrocatalytic oxidation were studied. The major research work and results for this dissertation are as follows:1. The electrochemical deposition was employed to prepare nanocrystalline ZnO/EY hybrid porous thin films from solution containing dye with adsorption group. ZnO is hexagonal wurtzite crystal. Single crystal ZnO has preferred growth direction perpendicular to the FTO conductive glass substrate along the c-axis. In the more negative potential, we can deposit a thicker film. Through desorption and re-adsorption process, eosinY sensitized nanocrystalline ZnO films can be prepared. This kind of film was applied to dye-sensitized solar cells presenting good photoelectric properties2. Porous crystalline SnO2 thin films were successfully electrodeposited from an oxygen-saturated acid aqueous solution of SnCl2 containing different concentrations of butyl rhodamine B (BRhB) at 70℃. HCl was added to suppress hydrolysis of SnCl2, BRhB can be dissolved in the acid deposition solution due to its substitutes of amidocyanogen, and can adsorb on the surface of SnO2 due to its carbonate group. Therefore, it was used as a structure-directing agent to control the crystal growth of SnO2 and thus affects the crystalline structure and surface morphology of the deposited film. The electrodeposited thin films show porous morphology and rutile-type SnO2 crystalline structure due to addition of BRhB, and these structure features were controlled by the added amount of BRhB. The SnO2 thin film electrodeposited with addition of BRhB exhibits electrocatalytic characteristic enhancement on oxidation of phenol due to its porous structure.3. SnO2 nanobelts were synthesized by the water-assisted vapor deposition method using high pure Sn particles as the source materials. The SnO2 nanobelts synthesized by this method have rutile structure and smooth surface. The SnO2 thin film prepared by SnO2 nanobelts has good electrocatalytic activity to degrade phenol.