Bright Near-Infrared Emission in Molybdenum Ions Doped with Lead-Free Double Perovskites

In this work, lead-free perovskite Cs2SnCl6:Mo4+ powder was synthesized via a precipitation method. Bright near-infrared (NIR) emission (750–1100 nm) was achieved under photoexcitation by doping metal ion Mo4+ into lead-free perovskite. Density functional theory (DFT) analyses suggest that the NIR emission arises from the d-d transition of the incorporated Mo4+. The structural characteristics and NIR luminescence properties of the doped material were analyzed using XPS, XRD, and UV–visible (UV–vis) diffuse reflectance spectroscopy. The phosphor-converted light-emitting diodes (pc-LEDs) device fabricated using Cs2SnCl6:Mo4+ demonstrates excellent luminescence stability across driving currents ranging from 100 to 600 mA and shows promising potential for applications in vein imaging and night vision. This study provides insights into the design of NIR-emitting perovskite materials and paves the way for their practical applications in NIR technologies.