Application of Sb<sup>3+</sup>-Doped Cs<sub>2</sub>ZnCl<sub>4</sub> Single Crystals in Near-Infrared Imaging

Near-infrared emission has been widely used in night vision and smart devices due to their low thermal effects, non-invasion, and appropriate penetration. As a new generation of luminescent materials, metal halides are considered a promising next-generation near-infrared light source. Zinc-based halides have attracted much attention due to their excellent stabilities, low toxicity, and wide band gaps. However, most zinc-based halides composed of non-optically active [ZnX 4 ] 2- units exhibit poor photoluminescence quantum yields (PLQYs). In this paper, Sb 3+ ions were doped into Cs 2 ZnCl 4 single crystals to regulate their luminescence properties and investigate corresponding emissive mechanisms. Sb 3+ -doped Cs 2 ZnCl 4 single crystals exhibit efficient near-infrared emission, which is attributed to the self-trapped excitons emission of Sb 3+ . The prepared near-infrared LEDs based on Sb 3+ -doped Cs 2 ZnCl 4 exhibit excellent near-infrared imaging performance, demonstrating the potential application of zinc-based halides in military night vision.