High photoluminescence quantum yield of TiO2 nanocrystals prepared using an alcohothermal method.

Highly dispersible TiO2 nanocrystals (approximately 6 nm) were prepared by an alcohothermal method. A strong and stable photoluminescence emission with a maximum at 450 nm was observed in the original TiO2 nanocrystals colloid. Compared with the emission from quinine sulphate in 0.05 mol/L sulphuric acid, the emission quantum yield of TiO2 nanocrystals was determined to be about 0.20, which was much higher than the values (0.002 and 0.001) reported in previous studies. The fluorescence micrograph of TiO2 nanocrystals encapsulated in lipsomes shows that TiO2 nanocrystals prepared in such a way have potential application as a fluorescence probe in biological imaging. Research on the luminescence mechanism indicates that the surface state and extent of crystallization of the TiO2 nanocrystals are crucial factors in the high photoluminescence quantum yield obtained in this study.