Spectroscopic characterization of La1/2Na1/2TiO3 nanocrystals prepared by a stearic acid gel process

Perovskite-type La1/2Na1/2TiO3 nanocrystals were prepared by a stearic acid gel method. Photoluminescence spectra of the samples were recorded on a fluorescence spectrometer at room temperature. The general appearance of the spectra was similar in all samples. For the sample with a grain size of 14 nm, a strong blue luminescence band with a peak at 480 nm was observed, and the peak intensity of the band was influenced strongly by the grain sizes. In the case of bulk titanates, room-temperature photoluminescence could not be observed due to thermal quenching. The results show that size and surface effects play an important role in determining the luminescence of the nanosized materials.