Ratiometric optical thermometer with high-sensitive temperature sensing based on synergetic luminescence of Ce3+-Eu2+ in LiSr4(BO3)3 phosphors

Abstract Single-phase Ce3+, Eu2+ co-doped LiSr4(BO3)3 phosphors are successfully prepared via solid reaction process. The crystal structure, luminescence characteristics and thermal quenching performance of LiSr4(BO3)3:Ce3+, Eu2+ samples are systematically studied. The presence of two crystallographic positions of Sr2+ ions in LiSr4(BO3)3 host makes the emission bands of Ce3+ ion and Eu2+ ion exhibit asymmetry. Based on the configuration coordinate model, the thermal quenching of luminescence from Ce3+ ion and Eu2+ ion is investigated in detail. The temperature-sensitive performance is further studied by analyzing the temperature-dependent luminescence spectra of LiSr4(BO3)3:0.06Ce3+, 0.04Eu2+ phosphor. The maximum absolute and relative sensitivities are 0.057 K-1 and 4.017% K−1, respectively, which are better than many previously reported inorganic optical thermometry materials. Besides, the emissions of Ce3+ ion and Eu2+ ion are clearly separated, providing good signal discrimination ability. The results demonstrate that LiSr4(BO3)3:Ce3+, Eu2+ phosphors have outstanding temperature-sensitive properties and can be the excellent optical thermometric materials.