Efficient broadband near-infrared emission based on copper-alloyed metal halides

Recently, metal halides have shown broad application prospects due to excellent electronic and optical properties. Although significant developments have been realized, the spectra range of their photoluminescence (PL) emission is mainly limited to the visible region. Near-infrared (NIR) emitting materials are widely used in the fields of night vision, biomedical imaging, non-destructive food inspection, etc. On this occasion, extending the luminescence scope of metal halides to NIR region is of great significance. Generally, NIR-emitted metal halides are realized through rare earth (RE) ions doping. However, RE luminescence usually have narrow-band characteristics, which makes it difficult to realize broadband NIR emission. In this study, we present an efficient broadband NIR-emitted metal halide CsAgBr2 through copper ions alloying, its emission locates at 830 nm with a large FWHM (full width at half maximum) of 332 nm. Theoretical calculations suggest that the incorporation of Cu+ could effectively modulate the density of states and enhance the localized characterization, which is beneficial to boost the PL efficiency. Furthermore, this material displays favorable structure stability under ambient conditions. This study demonstrates the great application potential of Cu+-alloyed CsAgBr2 in the field of NIR optical electronics.