Kinetics of TiO2 photochromic response in different hole scavenging solvents

Abstract

There has recently been a renewed interest in the photochromic properties and uses of TiO₂ as a potential candidate for smart windows. However, the surrounding medium of TiO₂ nanoparticles (NPs) is of equal importance, as it facilitates hole scavenging and, in turn, photochromism. Here, we investigated the impact of scavenging power on the photochromic properties of TiO₂. TiO₂ NP colloids in these solvents exhibit a photochromic response in a broad wavelength range from the visible to near-infrared region. We have shown that solvents such as ethanol have the best hole scavenging properties among the alcohols tested. The response can be further modified by the addition of a supplementary hole scavenger, such as hydroxylamine. The photochromism of TiO₂ is fully reversible and could be used for applications in smart windows.