Modulation of mixed-phase titania photoluminescence by oxygen adsorption

We investigate the effect of oxygen (O-2) adsorption on photoluminescence properties of mixed-phase titania nanoparticle films deposited by femtosecond pulsed laser deposition, aiming to assess preliminary conclusions about the feasibility of opto-chemical sensing based on titania. We evidence that O-2 produces opposite responses in rutile and anatase photoluminescence efficiency, highlighting interesting potentialities for future double-parametric optical sensing based on titania. The results evidence an important role of lattice oxygen atoms, suggesting that the standard Schottky barrier mechanism driving the response toward gas species in most used metal-oxide sensors (e. g., tin dioxide) is not the only active mechanism in titania. (C) 2014 AIP Publishing LLC.