High-performance Cr3+-doped Sr2AlNbO6 double perovskite for near-infrared night-vision applications

Double-perovskites materials are suitable matrices for hosting Cr 3+ ions to achieve highly efficient near-infrared (NIR) luminescence. In this study, the Sr 2 AlNbO 6 : x Cr 3+ (SANO:0.15 % Cr 3+ ) phosphors were synthesized by doping Cr 3+ ions into the double perovskite Sr 2 AlNbO 6 (SANO) using a high-temperature solid-state method. The substitutional preferences of Cr 3+ ions in the lattice were systematically investigated, considering variations in ionic radius, crystal field strength, and energy transfer dynamics. The optimal SANO:0.15 % Cr 3+ phosphor exhibited narrowband NIR emission centered at 760 nm (700–900 nm) under 323 nm excitation, with distinct phonon sidebands. The strong crystal field environment was evidenced by a Dq / B value of 2.66. The phosphor demonstrated outstanding performance, including an internal quantum efficiency of 66.1 %, absorption efficiency of 43.0 %, and external quantum efficiency of 28.4 %. Additionally, it exhibited excellent thermal stability, retaining 52 % of its room-temperature emission intensity at 423 K. When incorporated into an NIR pc-LED device with a 310 nm chip, the phosphor enabled clear imaging of objects in dark environments using an NIR camera. These results underscore the potential of SANO:0.15 % Cr 3+ phosphors for night-vision illumination and next-generation NIR technologies.