Spectroscopic properties of LaAlO3 nanocrystals doped with Tb3+ ions

Terbium-doped LaAlO3 nanopowders were obtained by the Pechini method. The perovskite structure was confirmed by XRD data. LaAlO3 was synthesized already at 700 °C. The crystalline size depends on annealing temperature and varies from 25 nm for 700 °C to 36 nm for 1000 °C. Obtained nanocrystals exhibit strong green emission from the 5D4 level, centered at 543.4 nm. Emission from the 5D3 level is also observed; its intensity decreases with increasing of Tb3+ concentration. Emission from color centers is observed at about 730 nm, its intensity increases with annealing temperature and decreases at higher terbium concentration. Formation of the color center is due to excess of oxygen and La vacancies. A decay time of the 5D4 emission depends on crystalline size and weakly depends on Tb3+ concentration (in the 0.5–5 at% range).