Simultaneously boosting visible and near-infrared luminescence of Ho in Cs2AgInCl6 double perovskites via Bi3+ sensitization

The emergence of near-infrared (NIR) luminescence from lanthanide (Ln 3+ ) ions doped lead-free Cs 2 AgInCl 6 double perovskites (DPs) has garnered significant attention due to its extensive range of potential applications. Unfortunately, they still suffer from weak NIR emission due to the inherent wide band gap of DPs resulting in inefficient energy transfer from the host to Ln 3+ . Herein, Bi 3+ can act as the sensitizer to activate Ho 3+ emission and reduce the excitation energy in Cs 2 AgInCl 6 : Ho. Under 400 nm excitation, Bi 3+ co-doped Cs 2 AgInCl 6 : Ho shows 39 times and 21 times higher emission intensity than Cs 2 AgInCl 6 : Ho in Visible and NIR. As a result, a photoluminescence quantum yield of 18.63 % ranging from 800 to 1600 nm can be obtained. Finally, by coupling a Bi-doped sample with a commercial near-ultraviolet LED chip (395 nm), a compact Vis-NIR ultrawideband light source was prepared, which has promising applications in multifunctional illumination and night vision.