Electrically-Driven Violet Light-Emitting Devices Based on Highly Stable Lead-Free Perovskite Cs₃Sb₂Br₉ Quantum Dots

Recently, substantial progress has been made in perovskite-based light-emitting devices (LEDs) with near-infrared, red, green, and blue emissions. However, short-wavelength perovskite LEDs targeted at violet emission remain a great challenge. Moreover, the majority of previously reported devices were focused on the conventional lead halide perovskites. In this study, for the first time, electrically driven violet emission (408 nm) from lead-free Cs3Sb2Br9 quantum dots (QDs) was demonstrated at room temperature, the shortest wavelength for perovskite LEDs as far as we know, and an external quantum efficiency of ∼0.206% was achieved. The device demonstrated an excellent working stability. After a long-term running for 6 h, almost 90% of the initial electroluminescence performance was retained, and no current density rising occurred with the running time. The results obtained suggest that the lead-free Cs3Sb2Br9 QDs are potentially attractive candidates for the preparation of environment-friendly and stable violet LEDs, making practical applications of them a real possibility.