Fatigue-resistant, temperature-insensitive strain behavior and strong red photoluminescence in Pr-modified 0.92(Bi0.5Na0.5)TiO3-0.08(Ba0.90Ca0.10)(Ti0.92Sn0.08)O3 lead-free ceramics

An electric-field-induced large strain and strong photoluminescence was achieved by introducing trivalent Pr3+ as the activator into 0.92(Bi0.5Na0.5)TiO3 − 0.08(Ba0.90Ca0.10)(Ti0.92Sn0.08)O3 (BNT−8BCST) ceramics. Around a critical composition of 0.4 mol% Pr3+, a large strain of ∼0.39% with a relatively small hysteresis compared with existing lead-free Bi-perovskite ceramics was obtained. In particular, the strain is very resistant to field cycling and thermal shock, giving the materials attractive for its exceptionally good fatigue resistance and high temperature stability. Besides the excellent electrical properties, Pr3+-modified BNT−8BCST host exhibits a strong photoluminescence with a bright red emission at 610 nm assigned to 1D2 → 3H4 transitions of the Pr3+ ions upon a blue light excitation of 400-500 nm. The photoluminescence can be enhanced through poling treatment of the samples. Moreover, samples have a superior water resistance property which almost maintaining the same photoluminescence intensity after 40 h water immersion time. These results suggest the material may have potential application as a multifunctional device such as “on-off” actuator and electric field-controlled photoluminescence devices by integrating its excellent luminescence and electrical properties.