Synthesis of tungsten trioxide Nanoarchitecture for Highly Efficient Photoelectrochemical Device

Abstract

Extrinsic and intrinsic properties of a PEC cell determine the performance of the PEC device. Many researches have been conducted with metal oxides such as ZnO and TiO2, but now that WO3 is being spotlighted as another promising material, it is worthwhile to further the study on WO3, especially nanoarchitectured WO3. Hence, this paper aims to figure out the optimal synthesis condition of WO3 nanoarchitecture which enables the PEC cell performance to maximize. Among various methods to synthesize nanoarchitecture, laser ablation method was adopted, and the experiment was designed to find the optimal combination of oxygen working pressure and growth temperature, which allegedly are the primary experimental parameters in laser ablation. And it was derived from the experiment that WO3 nanoarchitecture demonstrates the highest efficiency when the temperature is 500 °C and the working pressure is 300 mTorr. The increase of oxygen working pressure enhances the active surface area between electrode and electrolyte. On the other hand, the high oxygen working pressure leads to lower the conductivity and charge transfer efficiency at the interface. Furthermore, growth temperature controls the surface area, conductivity, and charge transfer resistance. The surface area decreased by increased growth temperature while conductivity and charge transfer efficiency were improved. This thesis focuses on the optimization of WO3 nanoarchitecture and the comparison with dense film to confirm the enhanced PEC performance by applying nanostructure. The results show the advantages of nanoarchitecture in that it improves charge transfer efficiency by shortening the hole diffusion pathway and suppressing the charge recombination rate. Extrinsic and intrinsic properties of a PEC cell determines the performance of the PEC device. Many researches has been conducted with metal oxides such as ZnO and TiO2, but now that WO3 is being spotlighted as another promising material, it is worthwhile to further the study on WO3, especially as a nanoarchitectured WO3.