Direct observation of electron-hole recombination kinetics in photoexcited semiconductor nanoparticles by ultrafast laser spectroscopy

摘要

Semiconductor photocatalytic rections have been investigated extensively. Titanium (IV) oxide (TiO_2) is one of the most promising photocatalysts because of its sufficient photostability and relatively higher photocatalytic activity. However, it has been also clarified that its photocatalytic activity strongly depends on its physical proprties. We have suggested that TiO_2 of both high surface area and high crystallinity, leading to, respoectively, enhancement of the capture of photoexcited electrons and positive holes by substrates and suppression of recombination, should show high photocatalytic activity.