Optical gas sensing of TiO2 and TiO2/Au nanocomposite thin films

The optical gas sensing properties of virgin TiO2 thin films and with inclusion of dot- and rod-shaped gold nanoparticles (NPs) prepared by a sol–gel method and annealed at 200 °C have been investigated. The obtained nanostructures have been analysed from both optical and morphological points of view. In particular, the prepared films show interesting dynamic optical absorption sensing responses towards different kinds of alcohol vapours in the spectral range corresponding to the surface plasmon resonance (SPR) peak of the gold nanoparticles. Total attenuation surface plasmon resonance measurements in controlled atmosphere demonstrate a sensing activity due to variation of the thickness and the real part of the active sensing layer refractive index