Intense mechanoluminescence, thermoluminescence and photoluminescence in Pr3+ doped K0.02Na0.98NbO3 ferroelectric phosphor

Defect control is an important factor in the design of elastic-mechano-luminescence (EML) materials. In this work, the volatile ferroelectric K0.02Na0.98NbO3 phosphor was choose as a host, and with rare earth ion Pr3+. The material exhibited intense red photoluminescence (PL),long-persistent luminescence (LPL) and mechanoluminescence (ML) with the intensity peaked at 610 nm, which is ascribed to 1D2→3H4 transitions of Pr3+. The intense and recoverable red emission was observed under compression stress stimulation, indicating that EML was produced during the deformation process. By adjusting the concentration of Pr3+, a ferroelectric material that exhibited a high ML intensity, which much higher than the NaNbO3 system material was obtained. The thermoluminescence (TL) curve was used to explore the defect level of K0.02Na0.98NbO3: xPr3+ phosphors. Finally, a mechanistic model was proposed to illustrate the probable process of PL, TL and ML. Present study provided necessary information and knowledge for the further development of ML material system based on perovskite structure KXNa1-XNbO3.