Upconversion luminescence of Yb3+/Er3+ co-doped NaSrPO4 glass ceramic for optical thermometry

Abstract

In order to expand the types of up-conversion (UC) luminescent materials used for optical thermometry, a novel Yb3+/Er3+ double doped glass ceramic (GC) containing NaSrPO4 nanocrystals was synthetised via melt quenching and heat treatment. The crystal structure morphology and UC optical properties were systematically studied, and the luminescence mechanism and energy transfer process were described. In addition, the relationship between the UC luminescence and temperature change of the GC specimen from 298 K to 573 K was measured under a 980 nm laser. The optical thermo-sensitive performance of GC was studied by the luminescence intensity ratio based on the thermally coupled emission states of Er3+, 2H11/2 and 4S3/2. For the GC sample annealed at 630 °C for 3 h, the maximum relative sensitivity Sr-max at 298 K was 1.78% K−1, the maximum absolute sensitivity Sa-max at 573 K was 5.28 × 10−3 K−1, which indicated that the GC materials might be potential candidates for optical temperature sensors.