Cr3+-activated phosphors have recently attracted significant research interest because their excellent luminescence properties are comparable to those of lanthanides, enabling diverse applications in modern optical devices. However, Cr3+ ions often encounter a spin-forbidden 2E→4A2 transition in a strong crystal field, such as AB2O4-type spinel oxides, causing a significant limited far-red-emitting performance. Herein, we adopted an effective antisite defect strategy for reducing the local lattice symmetry and breaking the forbidden transition of Cr3+ by constructing antisite defects based on ingenious Al-by-Zn substitution within the ZnAl2O4 matrix, thus converting harmful lattice defects into beneficial luminescence elevations. As a result, the emissive intensity of the Cr3+-activated phosphors was increased by 2.5-fold, while the internal quantum efficiency (IQE) increased from 46.40% to 73.74%. Moreover, rational ion doping of nonmetallic B3+, rare earth-based Y3+, and Lu3+ further reinforced the absorption and luminescence of phosphors by intensifying lattice distortion, which actualized diverse applications of plant lighting devices, light-converted films, and night vision. This antisite defect strategy provides a fresh perspective for an in-depth understanding of intrinsic structure-property relationships and the design of high-performance phosphors.
Wang et al. (Mon,) studied this question.