A broadband near-infrared phosphor BaZrGe3O9:Cr3+: The luminescence and application for light-emitting diodes

Recently, near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) have attracted considerable interest in the research field worldwide. As the key material, broadband NIR phosphors have become a research hotspot. Herein, a series of Cr3+-doped BaZrGe3O9 phosphors were successfully designed via nonequivalent substitution. The phosphors exhibited a broadband emission extending from 700 nm to 1200 nm (FWHM = 159 nm) with a maximum of ∼830 nm in the first biological window. To optimize the luminescence properties, the relationships between the doping concentration and crystal structure, luminescence spectra, decay curves were discussed. More importantly, the crystal field parameters Dq, B and Huang–Rhys factor were calculated, and the results may provide insight into factors determining and modifying the luminescence properties of the materials. The persistent luminescence of Cr3+ could also be realized, and the luminescence mechanism was proposed. Moreover, a pc-LED prototype was fabricated by combining the BaZrGe3O9:Cr3+ phosphor with a blue LED chip, and the potential application for broadband NIR pc-LEDs was discussed.