Temperature-dependent long persistent luminescence properties and trap distributions in Sr2MgAl22O36: Eu2+

Long persistent luminescence (LPL) materials can be released its stored energy by various temperature induced thermal disturbance for a period of time. However, the accelerated release of trapped carriers at higher temperatures inhibits the use of LPL materials in extreme environments. In this work, a series of blue-emitting LPL phosphors Sr2MgAl22O36: Eu2+ were prepared by high temperature solid phase reaction. The investigation of photoluminescence (PL) and LPL preliminary indicated that the optimal room-temperature LPL time is 80 s, and the depth of trap was about 0.84 eV and 1.078 eV. Analyses of temperature-dependent LPL decay curves and thermoluminescence (TL) spectra show that the LPL initial brightness and duration time increase first and then decrease with the increase of temperature, and the optimal temperature is 453 K. These findings ensure the application of the discovered LPL phosphors above room temperature, including optical information storage and anti-counterfeiting among others.