Fabrication of TiO2 Micropatterns on Flexible Substrates by Vacuum‐Ultraviolet Photochemical Treatments

Titanium dioxide (TiO2) micropatterns have received great attention for application in photocatalysis, electronics, and optoelectronics. Formation of such micropatterns on polymer substrates is of importance in flexible device fabrication. Vacuum ultraviolet (VUV) oxidative treatment applied on metalorganic precursor gel films serves as a strategy to fabricate metal oxide films on heat‐sensitive substrates such as polymers. Here, 172 nm VUV oxidative treatment through a photomask is used to directly convert the titanium metalorganic precursor films into TiO2 patterns without further heat annealing. In comparison to the commonly used alkoxide‐based precursors, titanium acetylacetonate proves to be an appropriate precursor due to its chemical stability in an ambient environment. With this precursor, clear removal of untreated precursor gels is achieved, resulting in well‐defined amorphous TiO2 micropatterns with a minimum feature of 1 µm and a small edge roughness less than ≈4%. The innovativeness arises from the one‐step VUV photochemical conversion in the whole ambient conditions, which largely reduces complex processes, for example, nitrogen‐filled glovebox or post‐heat treatments. High‐quality amorphous TiO2 micropatterns can be applied to device fabrication of solar cells and memories. This patterning approach highlighting TiO2 can be also extended to other metal oxides, which has great potential in surface and device processing. A one‐step vacuum ultraviolet treatment applied on titanium acetylacetonate gel films directly generates titanium dioxide (TiO2) micropatterns on polymer substrates in the whole ambient conditions. Deliberate processes such as glovebox and heat treatments are no longer needed. Energy‐dispersive X‐ray spectrometry element mappings reveal clear removal of untreated precursor gels from the undesired regions, which leads to high‐quality inorganic TiO2 patterns.