Modulating A site compositions of europium(iii)-doped double-perovskite niobate phosphors

Abstract

A series of novel red-emitting europium(III) (Eu³⁺)-doped double-perovskite niobate phosphors were synthesized by modulating the A site composition. In this respect, Ca₂InNbO₆:Eu³⁺ showed an outstanding quantum efficiency value (87.00%) because the Eu³⁺ ion substituted the absolutely non-centrosymmetric site in the Ca₂InNbO₆ matrix with a highly distorted [InO₆] octahedron as determined by analyzing its electronic structure, occupying environment, and photoluminescence performances. Impressively, such high-efficiency red-emitting Ca₂InNbO₆:Eu³⁺ phosphors exhibited the best structural rigidity among other prepared phosphors by calculating the Debye temperature. As such, Ca₂InNbO₆:Eu³⁺ revealed good thermal stability (the emission intensity remained about 74.87% at 423 K) and the accordingly fabricated white light-emitting diode exhibited a superior color rendering index (CRI = 93.35). Moreover, the potential of the prepared phosphors in applications of flexible anti-counterfeiting films and luminescent lifetime thermometers was also studied.