Photoelectrochemical study of TiO2 inverse opals

Abstract

The optical and photoelectrochemical behaviour of TiO₂ inverse opals and TiO₂ disordered macroporous structures has been investigated by means of UV-vis spectroscopy, cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. These techniques, together with photonic band structure calculations, confirmed the better absorption of light of TiO₂ inverse opals, due to the slow light phenomenon, and indeed the status of metamaterials for such structures. TiO₂ inverse opals and TiO₂ disordered macroporous structures are shown to have the same recombination rate of photogenerated charge carriers, but TiO₂ inverse opals are characterized by a better reactivity towards O₂ which can also contribute to the improvement of the photocatalytic activity observed by several groups.