Tuning Shortwave Infrared Emission Wavelengths by Chemical Pressure in Cr³⁺,Ni²⁺ Co‐Doped Spinel Phosphors

Abstract A chemical pressure‐induced shortwave infrared emission tuning strategy is constructed through partially inverse to normal and inverse spinel structural evolution. MgGa 2 O 4 :Cr 3+ ,Ni 2+ solid‐solution systems with Al 3+ and Sn 4+ cation dopants are synthesized, and crystal phase change is observed. Electron paramagnetic resonance investigations reveal different results of how cation substitutions affect the microstructure of the Cr 3+ clusters in two solid‐solution series. The photoluminescence analysis presents tunable broadband Ni 2+ emission, whose peak position can be effectively controlled from 1215 to 1465 nm via chemical pressure. Finally, phosphor‐converted light‐emitting diodes are prepared to demonstrate potential applications of shortwave infrared light sources on bio‐image and anti‐counterfeiting fields. Under 300 mA driving current, the radiant flux for Mg 0.98 Ga 0.94 AlO 4 :0.06Cr 3+ ,0.02Ni 2+ and Mg 1.48 Ga 0.94 Sn 0.5 O 4 :0.06Cr 3+ ,0.02Ni 2+ is 55.76 and 33.41 mW, respectively. This work provides insight into the chemical pressure affecting photoluminescent properties of Cr 3+ cluster‐contained spinel phosphors and reveals the importance of shortwave infrared light sources in various applications.