High‐temperature persistent luminescence and visual dual‐emitting optical temperature sensing in self‐activated CaNb 2 O 6 : Tb 3+ phosphor

Abstract The long persistent luminescence (PersL) and color adjustable properties in high‐temperature environment are of great significance for luminescent materials in the fields of multiple anti‐counterfeiting, biological imaging, and optical temperature sensing (OTS). In this work, a series of self‐activated CaNb 2 O 6 (CNO): Tb 3+ phosphors have been successfully synthesized by solid‐state reaction route, the OTS, and temperature‐dependent PersL of these phosphors is carried out and investigated in detail. Relying on the energy transfer from host to the activator Tb 3+ ion, the visual color‐tunable emissions from blue to green were detected with the increase of temperature and the maximum absolute and relative sensitivities reach 0.955% K ‐1 and 1.243% K ‐1 . Moreover, the temperature‐dependent PersL characteristics were investigated systematically, and the initial brightness and the lasting time all reach a maximum value at 323 K in the representative CNO: 1%Tb 3+ sample. All the results show that the high‐temperature persistent phosphor has potential applications in OTS and anti‐counterfeiting field.