Tunable photoluminescence properties of Pr3+/Er3+-doped 0.93Bi0.5Na0.5TiO3–0.07BaTiO3 low-temperature sintered multifunctional ceramics

Pr3+/Er3+-doped 0.93Bi0.5Na0.5TiO3–0.07BaTiO3 ceramics have been fabricated at a low sintering temperature of 960°C using a sintering aid of Li2CO3. The effects of energy transfer between Pr3+and Er3+on their photoluminescence properties have been investigated. Our results reveal that the down-conversion emissions of Pr3+are weakened and the lifetimes are shortened by the co-doping of Er3+. As a result, when both Pr3+and Er3+are excited simultaneously, with increasing the concentration of Er3+, the green emissions from Er3+increase but the red emissions from Pr3+decrease. Moreover, the emission color of the ceramics can be reversibly changed between red, yellow and yellowish green by using excitation sources of different wavelengths. Strong up-conversion green emissions with short lifetimes arisen from Er3+have also been observed for the ceramics under the excitation of 980 nm. Owing to the Li2CO3 sintering aid, the low-temperature sintered ceramics also exhibit reasonably good ferroelectric and piezoelectric properties, and hence should be promising for multifunctional applications such as electro-optical coupling devices.