Thermally stimulated color-tunable performance of Ca3Ga4O9: Bi3+ by co-doping with alkali metal ions

Abstract

Thermally stimulated color-tunable persistent luminescent materials can serve in many practical applications. Integrating color-tunable luminescence into a stable charge carrier trapping phosphor is a promising strategy but remains a challenge. In this work, by co-doping with alkali metal ions, Ca2.90Ga4O9: 5 mol% Bi3+, 5 mol% A+ (A+= Li+, Na+, K+) phosphors show noticeable thermal stimulated luminescence color-tunability. Among these samples, the phosphor co-doped with Na+ shows a dramatic color variation with temperature from cyan (513 nm) at 99 °C to yellow (602 nm) at 237 ℃. Further studies confirm that the thermally stimulated color-tunable feature of the sample is attributed to the interplay between dual traps and different emission centers. This work reports the dynamic color-tunable persistent luminescence under different temperatures in alkali metal ions co-doped gallate and provides a new perspective for the design of thermally responsive dynamic optical materials for the application of visual temperature warning or counterfeiting.