NaLa(MoO4)2: Sm3+, Tb3+ phosphor: Optical temperature sensing material with a wide change range of luminescence color

Abstract In this work, a temperature-sensitive material based on FIR was studied. A train of NaLa(MoO4)2: x% Sm3+, 5% Tb3+ (x = 0.1, 0.3, 1, 1.5) phosphors was synthesized via the hydrothermal method. The microstructure and the morphology of developed phosphors were investigated with the help of XRD and FE-SEM, and the phosphors temperature-dependent emission spectra were surveyed. Since the thermal quenching behavior for the Sm3+ with Tb3+ ions varied, the FIR of the Sm3+ and Tb3+ in molybdate showed significant temperature dependence at 303 K–603 K, which indicates that the prepared samples could be used for temperature measurement. The experimental data show that the sensitivity of the phosphors increased with the Sm3+ concentration. The sensitivity was found to reach a maximum value of 0.2521 K−1 at 603 K (the Sm3+ concentration was 1.5%). The relative sensitivity increased with the Sm3+ concentration at 303–410 K, and it decreased with the Sm3+ concentration increase at 460–603 K. Its maximum value was 1.90% K−1 at 506 K when the Sm3+ concentration was 0.1%. Additionally, it can be seen the luminescence color of the materials continuously changed from green to orange-red at 303–603 K, which could be used to characterize the temperature change.