Anomalous Tb3+ luminous spectrum in the TiO2 nanocrystals

Abstract In order to get Tb 3+ luminescence in the TiO 2 nanocrystals, nanoaggregate of terbium oxide in the TiO 2 nanocrystal has been produced using a reverse micelles and solvothermal method in toluene solution. Transmission electron microscopy and X-ray diffraction measurements have identified particles with average size of 6.7–10.2 nm in the anatase phase corresponding to the sintering temperature. The time-resolved spectroscopic technique has been used for the measurement of luminescence spectra and decay curves. No emission from Tb 3+ ions was observed from the sample with Tb 3+ ions dispersed in TiO 2 . However, from the sample that terbium oxide is formed a colony of aggregates in the TiO 2 solution strong emissions from 5 D 4 levels of Tb 3+ ions were observed. The PL spectrum was very anomalous, extraordinarily it has a very strong emission band due to the transition of 5 D 4 → 7 F 2 . It was proposed to describe anomalous spectrum that two kinds of energy migrations ( 5 D 4 – 7 F 6 and 5 D 4 – 7 F 2 ) are occurred among Tb 3+ ions, and quenching centers located at the boundary of titanium oxide powerfully operate to higher energy.