Near-infrared luminescence in Ca3ZnMGe3O12:Cr3+ (M = Zr, Hf, Sn, Ti) garnet family for light-emitting diode applications

Near-infrared (NIR) phosphors as crucial components of NIR light sources have multifunctional and smart spectroscopy applications, prompting an increasing research interest in developing efficient and stable NIR materials. Focusing on this issue, the present study explored the luminescent properties of Cr 3+ -doped Ca 3 ZnMGe 3 O 12 (M = Zr, Hf, Sn and Ti) garnet family. These materials exhibit an emission peak falls within the range of 785–805 nm with a full width at half maximum (FWHM) varying from 114 to 123 nm. Among them, the Ca 3 ZnZrGe 3 O 12 :Cr 3+ phosphor shows the highest photoluminescence quantum yield (PLQY = 60.3 %) and an excellent thermal stability ( I 423K / I 298K  = 77.51 %). Moreover, the performance of a prototype Ca 3 ZnZrGe 3 O 12 :Cr 3+ -containing NIR pc-LED device was estimated, which achieves an NIR output of 23.46 mW and a photonic efficiency of 14.09 % under 100 mA driving current. Non-destructive examination can be realized using this light source, demonstrating the good potential of the material in NIR spectroscopy applications.