A multi-mode optical thermometry based on the up-conversion La2MgGeO6: Er3+, Yb3+ phosphor

The up-conversion (UC) La 2 MgGeO 6 : Er 3+ , Yb 3+ phosphors were prepared by a high-temperature solid-phase method. The structural phase and luminescence characteristics of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence spectra . The research systematically investigated a multi-mode optical thermometry based on fluorescence intensity ratios (FIR) of the thermal-coupled energy levels 2 H 11/2 / 4 S 3/2 , non-thermal-coupled energy levels 4 S 3/2 / 4 F 9/2 , and the fluorescence lifetime of the 4 S 3/2 state. Based on these methods, the maximum relative sensitivity reached 1.130%K −1 , 0.623%K −1 , and 2.914%K −1 , respectively. According to the results, the manufactured samples have remarkable temperature measuring performance, which is characterized by a broad temperature measurement range, high sensitivity, and superior stability.