Low-Temperature Fabrication of Mesoporous Titanium Dioxide Thin Films with Tunable Refractive Indices for One-Dimensional Photonic Crystals and Sensors on Rigid and Flexible Substrates

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• 作者：Cheng Li ; Nicholas S. Colella ; James J. Watkins
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 24, 2015
• 年：2015
• 卷：7
• 期：24
• 页码：13180-13188
• 全文大小：475K
• ISSN：1944-8252

文摘

Highly transparent mesoporous titanium dioxide (TiO₂; anatase) thin films were prepared at room temperature via ultraviolet (UV) irradiation of hybrid polymer鈥揟iO₂ nanoparticle thin films. This approach utilized a UV-curable polymer in conjunction with the photocatalytic activity of TiO₂ to form and degrade the organic component of the composite films in one step, producing films with well-controlled porosity and refractive index. By adjustment of the loading of TiO₂ nanoparticles in the host polymer, the refractive index was tuned between 1.53 and 1.73. Facile control of these properties and mild processing conditions was leveraged to fabricate robust one-dimensional photonic crystals (Bragg mirrors) consisting entirely of TiO₂ on silicon and flexible poly(ethylene terephthalate) substrates. The mesoporous Bragg mirrors were shown to be effective chemical vapor sensors with strong optical responses.