Charge-carrier dynamics in titania powders

Abstract

Contactless transient photoconductivity measurements in TiO{sub 2} powder are presented. Large differences between the modifications anatase and rutile are observed with anatase exhibiting higher yields and longer lifetimes of photoinduced excess charge carriers. It is shown that surface modification drastically changes the electron decay kinetics, where adsorption of 2-propanol and of tetranitromethane leads to a lower and a higher decay rate, respectively. Platinization opens an additional fast decay channel. The results are discussed in view of their relevance for photocatalysis.