Energy transfer from VO43- group to Sm3+ ions in Ba3(VO4)2:3xSm3+ microparticles: A bifunctional platform for simultaneous optical thermometer and safety sign

The Sm3+-doped Ba-3(VO4)(2) microparticles were successfully synthesized via a simple sol-gel method. Both the recorded three-dimensional photoluminescence (PL) emission spectra and counter lines revealed that the nearultraviolet light was a proper excitation lighting source for the studied samples. Under 352 nm of irradiation, the effect of Sm3+ ion concentration on the PL emission properties of the microparticles was investigated and the optimum doping concentration was demonstrated to be 4 mol%. Based on the diversity in the thermal quenching performance of VO43- group and Sm3+ ions, a novel self-referencing non-invasion optical thermometer with high sensitivity and superior signal discriminability was designed. By taking the advantage of the temperature-dependent fluorescence intensity ratio between the VO43- group and Sm3+ ions, the optical thermometric properties of the Sm3+-doped Ba-3(VO4)(2) microparticles in the temperature range of 303-463 K were analyzed. The maximum absolute and relative sensor sensitivities, which were hardly influenced by the PL emission intensity, were obtained to be 0.039 K-1 and 2.24% K-1, respectively. Furthermore, the emitting color of the resultant compounds was found to be significantly dependent on the external temperature. These results suggest that the Sm3+-doped Ba-3(VO4)(2) microparticles are a potential candidate for high-performance self-referencing optical thermometer and safety sign applications.