Length High sensitivity dual-mode ratiometric optical thermometry based on Bi³⁺/Mn⁴⁺ co-doped Ba₂LaTaO₆

While considering metal oxides co-doped by non-rare earth ions potential for non-contact luminescence thermometry applications, a series of novel Ba2LaTaO6:Bi3+, Mn4+ phosphors were synthesized and thoroughly tested. Herein we describe the synthesis procedure as well as the results of systematic characterization of the phosphors including phase structure, morphology, luminescence properties and thermal behaviour. The Ba2LaTaO6:Bi3+, Mn4+ phosphors revealed the presence of dual emission centres with different temperature responses. The maximum absolute and relative sensitivity of the Ba2LaTaO6:Bi3+, Mn4+ phosphors reached 0.029 K-1 and 3.81% K-1 in the 80-470 K range, respectively. At the same time, the apparent change of Ba2LaTaO6:Bi3+, Mn4+ emitting colour from blue at 80 K to red at 470 K was achieved, which is readily detected by eye. All the experimental results showed that Ba2LaTaO6:Bi3+, Mn4+ phosphors have a good potential for application as luminescence temperature sensors.