Multiple ways for temperature detection based on La2MgTiO6 double perovskite co-doped with Mn4+ and Cr3+ ions

Optical thermometers play an increasingly important role in enabling allowing work in harsh conditions in low temperatures. In this work, multiple ways of the non-contact temperature readout based on La2MgTiO6 double perovskite doped and co-doped with transition metal ions (Mn4+ and Cr3+) have been investigated for the first time. It was possible thanks to the occurrence of the host emission – [TiO6] groups, as well as the spin-forbidden emission 2E–4A2 of the Mn4+ and Cr3+ ions. The potential of the temperature sensing performance of La2MgTiO6: Mn4+, La2MgTiO6: Cr3+, and La2MgTiO6: Mn4+, Cr3+ luminescent thermometers was examined. It was found that the optimal concentration of manganese ions is 0.8 %. In addition, the La2MgTiO6:Mn4+, Cr3+ has the potential for a multimodal approach to temperature detection. It was shown that the relative sensitivity (Sr) can be easily modified by the sample composition and dopant concentration. The outstanding relative sensitivities of 2.68 % K−1 and 1.74 % K−1 at 220 K from La2MgTiO6: 0.1 % Cr3+ and La2MgTiO6:0.8 % Mn4+, 0.5 % Cr3+, respectively, were obtained.