Excellent optical thermometry based on upconversion emission in SrMoO_4:Er^3+ phosphor

In this paper, SrMoO4:Er3+ phosphor excited by 976 nm diode laser shows remarkably intense green and relatively weak red upconversion emissions. Subsequently, within the temperature range from 310.8 K to 629.4 K, we tested a temperature-dependent fluorescence intensity ratio originating from the thermally coupled 2H11/2 and 4S3/2 states. It is revealed that SrMoO4:Er3+ phosphor exhibits a high sensitivity of 0.0326 K−1 at 554.0 K, indicating that the phosphor can be regarded as a promising building block for optical temperature sensor.