Hybrid Lithographic Arbitrary Patterning of TiO 2 Nanorod Arrays.

In this work, we report a hybrid lithographic method that combines the top-down soft lithography and the bottom-up hydrothermal approach for growing single-crystalline TiO 2 nanorod arrays with arbitrary patterns. The arbitrary patterns of TiO 2 seeds were obtained through the microcontact printing of the TiO 2 seed precursor onto Si substrates using prepatterned poly(dimethylsiloxane) (PDMS) as stamps, followed by a baking process. Afterward, TiO 2 nanorod arrays were selectively grown on patterned TiO 2 seeds through conventional hydrothermal methods. By controlling the TiO 2 seed precursor concentration, the hydrothermal reaction time and temperature and the patterns, the morphology and density of the TiO 2 nanorods can be tuned in a controllable manner. Overall, this work provides a new strategy for the low-cost and facile preparation of patterned TiO 2 nanorod arrays that has potential applications in micro-nano-optoelectronic devices and other fields.