Au Nanoparticles Dispersed Inside Porous TiO_2 Thin Films: High Performance Optical Gas Sensors Through Localized Surface Plasmon Resonance Monitoring

摘要

Colloidal solutions of Au and TiO_2 nanoparticles are prepared and used as nanocrystal inks for the fabrication of porous thin films to be used as optical gas sensor. The introduction of Au nanoparticles in the TiO_2 matrix affects the reactions mechanism improving the sensing process, moreover the Au Surface Plasmon Resonance peak can be used for the realization of a gas sensor with tunable sensitivity. The effect of thermal treatment, Au dimension and concentration is analyzed in order to tailor films microstructure and their sensing properties. The nanocomposites showed reversible change in optical absorption/reflection when exposed to reducing gasses (H_2, CO) at 300 °C operative temperature or when exposed to volatile organic compounds (alcohols) at room temperature.