Strong red emission and enhanced electrostrain in (Bi_0.5Na_0.5)_0.935−xPr_xBa_0.065Ti_1−xSb_xO₃ lead-free multifunctional ceramics

Lead-free perovskite (Bi_0.5Na_0.5)_0.935−xPr_xBa_0.065Ti_1−xSb_xO₃ (BNBT6.5–xPS) ceramics are prepared by ordinary sintering technique. The compositional dependence of phase structure, electrical and photoluminescence properties of the ceramics was systematically investigated. Results showed that all samples exhibit pure perovskite structure with dense microstructures. With the addition of PS, a strong red emission located at 610 nm and a weak red emission at 660 nm under a light 450 nm excitation was observed. The strong red emission band is ascribed to the inter-4f transition from the excited ¹D₂ to the ground state ³H₄ and the weak red emission located at 660 nm is due to the ³P₀ → ³F₂ transition. And then the BNBT6.5–0.004PS ceramic exhibited the strongest photoluminescence property. Besides the excellent photoluminescence properties, PS modifications induced an enhanced filed-induced strain. At x = 0.001, a large strain of 0.31% was obtained at a driving field of 70 kV/cm. As a multifunctional material, it has potential application as a multifunctional device such as optical-electro integration and coupling device applications.