Optical temperature sensing properties of Stokes fluorescence-based high color-purity green-emitting Sr^sub 2^Gd^sub 8^(SiO^sub 4^)^sub 6^O^sub 2^:Er^sup 3+^ phosphors

Fluorescence intensity ratio (FIR)-based optical thermometry has attracted a great deal of attention because it allows accurate and reliable temperature measurements with high spatial resolution and real-time monitoring. Herein, we report the novel Sr2Gd8(SiO4)6O2:Er3+ (SGSO:Er3+) phosphor as an optical thermometry material. The sol-gel method is used to synthesize the oxyapatite structured SGSO:Er3+ phosphors, which exhibits a rod-like morphology. The photoluminescence spectra of SGSO:Er3+ phosphors displays two distinct green emission bands corresponding to the electronic transitions 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2. The temperature-induced variations in the FIR result in a maximum sensitivity of 3.4 × 10−3 K−1 at 463 K. Further, the CIE chromaticity coordinates do not shift from the green region when the temperature is increased from 303 to 483 K and the color purity only decreasing from 77.6 to 71.4%. The SGSO:2Er3+ phosphor exhibits the color-purity of 93.5% when excited with low-energy electron beam. These results suggest that the SGSO:2Er3+ phosphor is a promising material for optical temperature sensors and display devices.