Yb3+/Mn2+ co-doped Y3Al5O12 phosphors for optical thermometric application

Yb3+/Mn2+ co-doped Y3Al5O12 phosphors are prepared by the high-temperature solid-phase reaction via sintering the raw materials at 1600 °C in reducing atmosphere. Orange-red up-conversion (UC) emission of Mn2+ was observed at room temperature. Under the 980 nm excitation, the orange UC emission band peaked at 585 nm was realized, which came from the 4T1(4G) → 6A1(S) transition of cooperative luminescence of Yb3+-Mn2+ dimers. Due to rapid decrease of the UC emission intensity with increasing temperature, high absolute sensitivity (Sa) and relative sensitivity (Sr) were obtained. The maximum value of Sa is 0.017 K−1 at 423 K, and the maximum value of Sr is 3.4% K⁻1 at 423 K. All the Sr value were over 1.7% K−1 in the range from 298 K to 423 K. The thermal reliability was 95.2% at 423 K and 96.9% at 298 K, respectively. In summary, YAG:Yb3+, Mn2+ can be a reliable candidate for optical temperature sensing.