We report three-dimensional (3D) nanostructures based on shape- and phase-controlled TiO2 coated transparent conducting oxide (TCO) nanowire array. Core-shell and branched nanostructures were obtained using an aqueous chemical bath deposition (CBD) method at room temperature. Adjusting the pH of a TiCl4 solution is a key factor that determines the morphology of the nanostructure. Spherical TiO2 anatase covered a Sb-doped SnO2 (ATO) nanowire when pH was maintained at a high level. In contrast, branched nanostructures with TiO2 rutile nanorods were synthesized by keeping a TiCl4 solution going down to a low pH. Nanorods were grown epitaxially along the  direction on ATO nanowires. Morphological and structural analysis indicates that phases and shapes of the 3D hybrid nanostructure are determined by the pH of the solution and the reaction time. A two-fold higher photoconversion efficiency of rutile TiO2 rod@ATO was obtained under simulated solar illumination compared to that of the anatase TiO2 nanoshell@ATO. These 3D hybrid nanostructures can offer (i) a large surface area and efficient charge transport in the TiO2 nanostructure, and (ii) an effective charge collection path through one-dimensional TCO, which is promising for various areas, including photoelectrochemical water splitting, as well as for application in electronic and photonic nanodevices.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology