GdMgAl11O19: Dy3+ Phosphor for Dual-Functional White Light LED Lighting and Ratiometric Optical Temperature Sensing

In this work, a GdMgAl 11 O19: Dy 3+ phosphor with dual functions of optical temperature sensing and white light illumination was synthesized using the high-temperature solid-state method. When excited by 348 nm UV light, the phosphor emits warm white light, and its luminescence behavior exhibits both overall thermal stability and local thermal sensitivity. By utilizing the reverse response characteristics of the luminescence intensity of two blue emission bands corresponding to Dy 3+ thermally coupled level transitions ( 4 F 9/2 → 6 H 15/2 , 452 nm; 4 I 15/2 → 6 H 15/2 , 476 nm) with temperature, its optical temperature sensing potential was explored using the fluorescence intensity ratio (FIR) method. Experimental results show that this phosphor can perform temperature detection over a wide range of 298-973 K, with a relative sensitivity of 0.746% K -1 at 298 K. Among all emission peaks, the 452 nm emission peak is a locally thermally sensitive peak, accounting for a very small proportion of the overall emission and having no decisive effect on the overall luminescence. The fluorescence intensities of the 476 nm blue, 570 nm yellow, and 663 nm red emissions, however, show consistent attenuation with increasing temperature. Even when the temperature rises to 423 K, the fluorescence intensity still retains 85% of its initial room temperature value, indicating excellent overall thermal stability. GdMgAl 11 O 19 : Dy 3+ phosphor integrates the dual functions of high-stability white LED and wide-range high-sensitivity optical temperature sensing. This study provides important reference for the application expansion of Dy 3+ -doped phosphors in LED devices and temperature detection systems, as well as for the development of multifunctional phosphors.