Tunable and efficient broadband short-wave infrared emission of Ni2+-activated spinel phosphors for advanced NIR light sources

Broadband shortwave infrared (SWIR) light-emitting diodes (LEDs) have attracted significant attention due to their widespread applications in spectroscopy, food industry, agriculture, optical communications, night vision, and biomedical technologies. Nevertheless, their performance remains limited by the critical phosphor layer's low quantum efficiency and narrow emission bandwidth. This work presents a series of Ni 2+ -doped spinel phosphors emitting in the SWIR range with high efficiency and tunable broadband emission. Upon UV illumination, normal spinel MgAl 2 O 4 :Ni 2+ phosphors exhibit an emission range of 1100–1600 nm and an internal quantum efficiency (IQE) of 5.2 %. By contrast, the inverse spinel MgGa 2 O 4 :0.02Ni 2+ demonstrates a significantly improved IQE of 77.2 % and excellent thermal stability (62.9 %@423 K), achieved by cation substitution. Furthermore, the significant spectral tuning over a broad range of 405 nm is realized through In 3+ cation- and F − anion-substitution in MgGa 2 O 4 :0.02Ni 2+ . Finally, SWIR pc-LEDs incorporating MgGa 2 O 4 :Ni 2+ phosphors were fabricated, and its potential applications in night vision, high-penetrating imaging, and non-destructive detection were evaluated. This work offers a promising pathway for developing tunable near-infrared light sources, thereby expanding their applicability across a range of advanced technologies.