Piezoluminescence from ferroelectric Ca_3Ti_2O_7:Pr^3+ long-persistent phosphor

A variety of up-and-coming applications of piezoluminescence in artificial skins, structural health diagnosis, and mechano-driven lightings and displays recently have triggered an intense research effort to design and develop new piezoluminescent materials. In this work, we deduced and verified an efficient piezoluminescence in ferroelectric Ca₃Ti₂O₇:Pr³⁺ long-persistent phosphor, in view of three fundamental elements forming piezoluminescence - piezoelectricity, luminescent centers and carrier traps. Under the stimulation of mechanical actions including compression and friction, Ca₃Ti₂O₇:Pr³⁺ shows an intense red emission from ¹D₂-³H₄ transition of Pr³⁺. On the basis of investigations on structural and optical characteristics especially photoluminescence, persistent luminescence and thermoluminescence, we finally proposed a possible piezoluminescent mechanism in Ca₃Ti₂O₇:Pr³⁺. Our research is expected to expand the horizon of existing piezoluminescent materials, accelerating the development and application of new materials.