Mg2+-modified LiBaF3:Ni2+ perovskite single crystals with broadband long wavelength near-infrared emission for imaging human vascular structures

Near-infrared (NIR) luminescence materials are ideal candidates for applications in three-dimensional biomedical imaging and night vision. Here, we constructed an ultra-broadband NIR material based on LiBaF₃:Ni²⁺ single crystals with NIR emission at 1400 nm and a full width at half maximum (FWHM) of 254 nm from 1100 to 1700 nm wavelengths, covering the NIR-II and NIR-III regions. Through the activation of inactive Mg²⁺, the NIR emission could be improved by a factor of two, and the FWHM enhanced to 273 nm. This is ascribed to the lattice distortion by the addition of Mg²⁺ as well as the charge asymmetry between the Mg²⁺ and Li⁺ ions. The prepared Ni²⁺/Mg²⁺-doped NIR perovskite single crystals were packaged with a commercial high-efficiency near-ultraviolet LED chip (@395 nm) to construct NIR single-crystal LEDs, and their promising applications with high efficiency were demonstrated in NIR night-vision monitoring and vein non-destructive imaging.