An Er³⁺ doped Ba₂MgWO₆ double perovskite: a phosphor for low-temperature thermometry

A bifunctional luminescent material is one of the most intriguing topics in recent years with significant growth in the number of investigations. Herein, we report the potential of Ba₂MgWO₆ doped with Er³⁺ as a candidate for white-light emitting phosphor and noncontact luminescent thermometry. The synthesis of the samples was carried out by the co-precipitation method. The influence of the dopant concentration on the emission intensity, as well as the capability of temperature readout, was investigated for the first time. The highest emission intensity exhibits a sample comprising 4% Er³⁺; above it, the concentration quenching process by the dipole-dipole interaction occurs. However, high quality white light generates Ba₂MgWO₆ with 0.5% of Er³⁺ due to the coexistence of the host and erbium ion emission with a CIE of (0.30, 0.35). To construct a non-contact luminescent thermometer based on Er³⁺, the ratio of the emission from ⁴I_11/2 → ⁴I_15/2 to the host emission was examined. The highest sensitivity S_r of the obtained luminescent thermometers was 2.78% K^-1 at 198 K. The repeatability of the calculated results and the uncertainty δT of the temperature readout were investigated.