Highly Efficient Broadband Near Infrared Emission Based on Copper-Alloyed Metal Halides

Abstract

Near-infrared (NIR) emitting materials are widely used in a variety of fields due to the properties of high penetration depth, minimal thermal effect, and no damage to skin tissue. However, producing broadband NIR emission with high luminescence efficiency and good structure stability remains a significant problem. In this study, we present an efficient NIR-emitted lead-free metal halide CsAgBr2 through copper ions alloying, which locates at 830 nm, with a FWHM (full width at half maximum) of 332 nm. Theoretical calculations show that the effective NIR emission may come from the self-trapped excitons, and the incorporation of Cu+ could effectively modulate the density of states population and enhance the localized characterization, which become the key factor drastically boosting the photoluminescence efficiency. Furthermore, in addition to its efficient broadband emission, Cu+-alloyed CsAgBr2 has good stability under ambient conditions, displaying favorable structure stability proofing moisture and oxygen. This study demonstrates the great application potential of Cu+-alloyed CsAgBr2 in the field of NIR optical electronics.

Keywords: photoluminescence, Metal halide, Near-infrared emission, self-trapped excitons