Rare-earth and transition metal ion single-/co-doped double-perovskite tantalate phosphors: Validation of suitability for versatile applications

Abstract

Novel rare-earth (RE; e.g., europium (Eu3+), samarium (Sm3+), and praseodymium (Pr3+)) and transition metal (TM4+; e.g., manganese (Mn4+)) ion single-/co-doped double-perovskite Ca2 InTaO6 (CITO) phosphors were prepared and investigated with respect to their crystal structure and photoluminescence (PL) properties. Among them, the CITO:Eu3+ phosphors were found to exhibit an ultra-high internal PL quantum yield (89.1%) and good thermal stability (78.7% at 423 K relative to the initial value at 303 K). As such, the corresponding packaged white light-emitting diode (LED) was able to display a remarkable color rendering index (CRI; = 91.51@10 mA). Besides, the potential in applications of anti-counterfeiting fields and a novel LED structure based on flexible phosphor-converted films was also studied. Moreover, due to their different thermal quenching, trivalent lanthanide (Ln3+)/Mn4+ co-doped CITO phosphors were designed for optical thermometry based on the luminescence intensity ratio (LIR) between different 4f transitions of various Ln3+ ions and2 Eg →4A2g (Mn4+) transition. Particularly, the LIR between the4 G5/2 →6 H9/2 and2 Eg →4 A2g peaks of the CITO activated with 5 mol% Sm3+ and 0.3 mol% Mn4+ exhibited the most excellent relative sensitivity (Sr; = 3.80 %·K−1) with beneficial temperature uncertainty of 0.0648 K. Overall, these results are of significance to offer valuable databases for constructing multifunctional high-performance optical platforms using single-/co-doped double-perovskite tantalates.