Efficient luminescence and photocatalytic behaviour in ultrafine TiO2 particles synthesized by arrested precipitation

Abstract

We have demonstrated optical and photophysical properties of newly synthesized ultrasmall TiO₂nanoparticles. The particles are synthesized by arrested precipitation method in trioctylphosphine oxide (TOPO) and benzophenone as the capping agent and also as solvent at high temperature in Ar atmosphere. High-resolution TEM and XRD measurements revealed that the particles are in the size range of 3.3–3.5 nm. Optical absorption spectra of these particles show large blue shift indicating a quantum confinement effect. The particles are highly luminescent, which is very unusual for an indirect band gap material. The emission quantum yield has been measured to be >2%. Again the photocatalytic activity of newly synthesized TiO₂ particles was found to be much higher as compared to TiO₂nanoparticles, indicating a better photocatalytic material arising due to size quantization.