Hybrid Lithographic Arbitrary Patterning of TiO₂ 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 TiO₂ nanorod arrays with arbitrary patterns. The arbitrary patterns of TiO₂ seeds were obtained through the microcontact printing of the TiO₂ seed precursor onto Si substrates using prepatterned poly(dimethylsiloxane) (PDMS) as stamps, followed by a baking process. Afterward, TiO₂ nanorod arrays were selectively grown on patterned TiO₂ seeds through conventional hydrothermal methods. By controlling the TiO₂ seed precursor concentration, the hydrothermal reaction time and temperature and the patterns, the morphology and density of the TiO₂ nanorods can be tuned in a controllable manner. Overall, this work provides a new strategy for the low-cost and facile preparation of patterned TiO₂ nanorod arrays that has potential applications in micro-nano-optoelectronic devices and other fields.