An Improved Strategy for High-Quality Cesium Bismuth Bromine Perovskite Quantum Dots with Remarkable Electrochemiluminescence Activities

Low-toxic trivalent bismuth, with the isoelectronic structure (6s26p0) and similar ionic radius to divalent lead, represents a promising candidate for constructing lead-free perovskites. Herein, cesium bismuth halide perovskite quantum dots (Cs3Bi2Br9 QDs) were synthesized via a comprehensively improved ligand-assisted reprecipitation method with the additions of γ-butyrolactone, trace distilled water, and tetrabutylammonium bromide, as well as the aid of ultrasonic technology. The as-prepared QDs displayed remarkable monodispersity, outstanding stability, and highly passivated surfaces with a near single-component PL decay, thus affording superb optical properties with photoluminescence quantum yield up to 37 %, outperforming all the reported bismuth-based perovskites. Furthermore, Cs3Bi2Br9 QDs were first attempted for electrochemiluminescence (ECL) and exhibited a stable and efficient ECL response following either annihilation or coreaction ECL mechanism. Not only did the optical properties and stabili...