Lattice Distortion‐Induced Performance Enhancement of Red Phosphors for White LEDs

Modulating the local coordination environment of the luminescent centers represents a compelling strategy for designing high‐performance red phosphors. However, it remains challenging for Eu‐doped phosphors to simultaneously achieve high internal quantum efficiency and negative thermal quenching performance. In this work, Ca 2 AlNbO 6 was selected as the matrix. The spatial arrangement of the Ca sites provides relatively separated substitutional positions for Eu, contributing to the high optimal Eu concentration of x = 0.18. At the optimized W concentration (y = 0.02), W incorporation modifies the local crystal field of Eu through structural coupling and enhances the local lattice rigidity. As a result, the phosphor exhibits a 3.98‐fold enhancement in emission intensity, an internal quantum efficiency of 98.2%, and an emission intensity of 121% at 423 K relative to that at 303 K. The fabricated white light‐emitting diode (WLED) presents a color temperature of 4238 K, and a color rendering index of 92.1. This work provides a feasible strategy for simultaneously optimizing luminescence efficiency and thermal stability in Eu − activated double‐perovskite phosphors.