Defect modulated luminescent and photochromic behaviors in Pr/Er codoped Na0.5Bi2.5Nb2O9 ceramics for display and optical storage

In order to explore the mechanism of luminescence modulation and photochromism of Na0.5Bi2.5Nb2O9 (NBN)-based photochromic materials, the luminescence, photochromism and luminescence modulation properties of Pr3+/Er3+ co-doped NBN ceramics under different sintering atmospheres (Air, O-2, and N-2) were systematically studied. The results show that the samples exhibit excellent properties of mull-color luminescence (red-green), mull-mode (upconversion/downshifting) luminescence properties. Correspondingly, the upconversion and downshifting emission intensities are significantly decreased for samples sintered at nitrogen. And, the luminescence switching contrast (Delta R-t) of the sample sintered in N-2 is also obviously lower than the Delta R-t values under air and O-2 atmospheres upon 405 nm irradiation. Such color and Delta R(t )value changes under different atmospheres are closely related to defects and traps due to Bi and Na element volatilizations, which are well verified by XPS analysis. Meanwhile, various pattern displays based on photochromic NBN materials can be well achieved with fast response and good fatigue resistance.