A Rare Blue-Light-Excitable—Near-Infrared-Emissive Copper(I) Iodide Hybrid with Facile Synthesis for Near-Infrared Imaging

Metal halide hybrid luminescent materials have attracted significant attention due to their tunable emission properties and excellent photoelectric performance. However, achieving metal halides that exhibit near-infrared (NIR) emission under blue light excitation remains a major challenge. This paper reports a novel 2D copper(I) iodide hybrid material, Cu 2 I 2 (THQx) (THQx = 5,6,7,8-Tetrahydroquinoxaline), which is constructed by linking -Cu 2 I 2 - chains with the THQx ligand and achieves broadband NIR luminescence. It can be effectively excited by blue LEDs and has a peak emission at 730 nm with a full width at half maximum of 159 nm. Theoretical calculations indicate that its luminescence originates from the triplet metal/halide-to-ligand charge transfer ( 3 MLCT/HLCT). This material also exhibits excellent thermal stability, air stability, and photostability, demonstrating potential applications in night vision and biological imaging in NIR phosphor-converted LED (pc-LED) devices. This research not only expands the application boundaries of copper(I) halide hybrid materials, but also provides a new approach for the development of low-cost and environmentally friendly NIR luminescent materials.