Intense red upconversion luminescence and optical thermometry of a novel Yb3+/Er3+co-doped Ba3Sc2WO9 phosphor

Yb3+/Er3+ co-doped Ba3Sc2WO9 strong red upconversion luminescent (UCL) phosphors have been achieved by high-temperature solid-phase method. Under 980 nm laser excitation, the phosphor emits strong red light at-667 nm and weak green light at-560 nm, with the intensity ratio of the red-green integrals up to 23.06. The band gap of the optimally doped Ba3Sc2WO9: 0.1 Yb3+, 0.03 Er3+ sample was calculated to be 3.14 eV. The main excitation process for the red light emission is the transition of Er3+ from the 4I13/2 energy state to the 4F9/2 energy state. In addition, the Yb3+/Er3+ doped Ba3Sc2WO9 red UCL phosphors have great potential for ambient temperature sensing in the temperature range 298-498 K. The Ba3Sc2WO9: 0.1 Yb3+, 0.03 Er3+ phosphor as a temperature sensor has a maximum sensitivity of 0.0096 K-1 at 498 K. This study provides a groundbreaking method for exploring new materials for strong red light upconversion emission.