Mixed-halide blue perovskites CsPb(Br/Cl)₃ are considered promising candidates for developing efficient deep-blue perovskite light-emitting diodes (PeLEDs), but their low photoluminescence quantum yield (PLQY), environmental instability, and poor device performance gravely inhibit their future development. Here, we employ a heteroatomic Cu²⁺ doping strategy combined with post-treatment Br⁻ anion exchange to prepare high-performance deep-blue perovskites CsPb(Br/Cl)₃. The Cu²⁺ doping strategy significantly decreases the intrinsic chlorine defects, ensuring that the inferior CsPbCl₃ quantum dots are transformed into two-dimensional nanosheets with enhanced violet photoluminescence and increased exciton binding energy. Further, with the post-treatment Br⁻ anion exchange, the as-prepared CsPb(Br/Cl)₃ nanosheets with more radiation recombination and less ion migration present an enhanced PLQY of 94% and better humidity stability of 30 days. Based on the optimized CsPb(Br/Cl)₃, we fabricated deep-blue PeLEDs with luminescence emission at 462 nm, a maximum luminance of 761 cd m⁻², and a current density of 205 mA cm⁻². This work puts forward a feasible synthesis strategy to prepare efficient and stable mixed-halide blue perovskite CsPb(Br/Cl)₃ and related blue PeLEDs, which may promote the further application of mixed-halide perovskites in the blue light range.

混合卤化物蓝色钙钛矿 CsPb(Br/Cl) ₃被认为是开发高效深蓝色钙钛矿发光二极管 (PeLED) 的有希望的候选者，但它们的低光致发光量子产率 (PLQY)、环境不稳定性和较差的器件性能严重抑制他们未来的发展。在这里，我们采用杂原子 Cu ²⁺掺杂策略结合后处理 Br ^-阴离子交换来制备高性能深蓝色钙钛矿 CsPb(Br/Cl) ₃。Cu ²⁺掺杂策略显着降低了本征氯缺陷，确保劣质 CsPbCl ₃量子点被转化为二维纳米片，具有增强的紫光光致发光和增加的激子结合能。此外，通过后处理 Br ^-阴离子交换，所制备的具有更多辐射复合和更少离子迁移的CsPb(Br/Cl) ₃纳米片呈现 94% 的增强 PLQY 和更好的 30 天湿度稳定性。基于优化的CsPb(Br/Cl) ₃，我们制造了深蓝色PeLED，其发光波长为462 nm，最大亮度为761 cd m ^-2，电流密度为205 mA cm ^-2。该工作提出了一种可行的合成策略来制备高效稳定的混合卤化物蓝色钙钛矿CsPb(Br/Cl) ₃ 以及相关的蓝色PeLED，这可能会促进混合卤化物钙钛矿在蓝光范围内的进一步应用。