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.