Customization of novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ red-emitting phosphors for luminescence lifetime thermometers with good relative sensing sensitivity

Luminescent thermometry with some outstanding advantages of quick response, large measurement range, and good sensing sensitivity has been widely investigated and suggested for practical applications as a kind of potential technique to detect real temperature. Herein, novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ red-emitting phosphors were prepared and further designed for the luminescence lifetime thermometers based on the temperature-dependent decay curves. At first, the crystal structure, morphology, and some luminescent properties (i.e., photoluminescence (PL) emission spectrum, concentration quenching mechanism, crystal field strength, chromaticity coordinate, color purity, quantum yield, thermal stability, and decay curve) of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were systematically analyzed and compared. Afterward, it revealed that the PL properties of Ca2InNbO6:Mn4+ phosphors were excellent compared to Sr2InNbO6:Mn4+ phosphors owing to the stronger crystal field strength of Mn4+ ion. Most interestingly, the relative sensing sensitivities of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were estimated as high as 3.30 % and 4.25 % K−1 with the low-temperature uncertainty of 0.11 and 0.09 K, respectively, indicating that the resultant novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ phosphors could be proposed for luminescence lifetime thermometers with high sensing sensitivity.