Abstract
The effectiveness of simultaneous etching and W-doping has been demonstrated in improving the quantum-dots anchoring and charge transport properties of CdS/TiO2 heterojunction films, thereby enhancing their photoelectrochemical performances. After the process of etching and doping, a rough and amorphous W-doped TiO2 shell is formed on the TiO2 nanorods surface. It can not only provide more active sites and larger surface areas for quantum-dots loading, light-harvesting and photoelectrochemical reaction, but also protect the electron-hole pairs from recombination at the interface. Furthermore, W-doping plays a role in motivating the separation and transfer of photo-generated carriers by introducing the intermediate energy level and inducing the positive shift of TiO2 conduction band, meanwhile prominently increase the amount of electrons due to the intrinsic valence difference between W6+ and Ti4+. Based on the above advantages, the uniform and compact deposition of CdS quantum-dots on the surface of etched and W-doped TiO2 nanorods pose a great influence on the establishment of the built-in electric field, heterojunction areas, light-capture ability, and the separation and injection efficiency of photo-generated carriers. Therefore, the optimal photocurrent density of improved CdS/TiO2 photoelectrodes is 7.05 mA cm?2, approximately 12 and 2.6-fold enhancement compared with conventional TiO2 and CdS/TiO2 photoelectrodes, respectively.
NSTL
Elsevier