The effect of annealing on the photoluminescence of layered perovskite H1.77[Sr0.8Bi0.21Ta2O7] powders

The microstructural and luminescent properties of H1.77[Sr0.8Bi0.21Ta2O7] powders under different dehydrating conditions were investigated. The powders were obtained by protonating Bi2SrTa2O9 powders in 3 M aqueous HCl solution, and were dehydrated by a post-annealing in air from 250 to 700 °C. The photoluminescence was enhanced for all dehydrated powders, especially for the sample annealed at 400 °C. The thermogravimetric analysis showed that there is an obvious dehydration temperature range from 200 to 400 °C, which was corresponding to the changing of the microstructure and photoluminescence in the same temperature range. The mechanism behind the experimental results was discussed.