Lattice Site Competition Regulates the Luminescence Centers of Cr ³⁺ ‐Doped NIR Phosphor for Phonon Sidebands Ratiometric Thermometer and Night Vision

Near‐infrared luminescent materials have attracted extensive attention based on their application prospects in many fields. Herein, the high‐efficiency near‐infrared luminescent material BaAl 3.772 Sb 2 O 12 :0.028Cr 3+ ,0.20Ga 3+ with internal and external quantum efficiencies of 97.5% and 34.4% have been reported. The BASO:Cr 3+ has two potential luminescent centers. Based on the lattice sites competition, the introduction of Ga 3+ successfully subtracted one luminescent center in the BASO: Cr 3+ phosphor. The lattice distortion analysis, the calculation of site occupation formation energy, and spectral analysis indicate that the occupation competitiveness of Cr 3+ at the AlO 6 site is weaker than that of Ga 3+ . After modification with Ga 3+ ions, the luminescence intensity is increased by ≈1.56 times. The luminescence intensity of the BASO:0.028Cr 3+ ,0.20Ga 3+ material at 423 K is 106.5% of that at room temperature, which is related to its high structural rigidity (Debye temperature = 468.9 K). Importantly, the material has potential optical temperature measurement applications due to its relative sensitivity of 3.46% K −1 at 198 K. Finally, the prepared NIR‐pc‐LED demonstrated potential applications in near‐infrared non‐destructive testing and night vision.