Perovskite light-emitting diodes (LEDs) show promises for next-generation displays owing to their excellent luminescent properties and low cost. Despite substantial progress with green- and red-emitting devices, the development of efficient blue perovskite LEDs has lagged behind. Here we demonstrate efficient blue perovskite LEDs based on a mixed two-dimensional–three-dimensional perovskite and a multifunctional ionic additive that enables control over the reduced-dimensional phases, non-radiative recombination channels and spectral stability. We report a series of devices that emit efficient electroluminescence from mixed bromide/chloride quasi-three-dimensional regions, with external quantum efficiencies of up to 21.4% (at a luminance of 22 cd m^–2 and emission peak at 483 nm), 13.2% (at a luminance of 2.0 cd m^–2 and emission peak at 474 nm) and 7.3% (at a luminance of 6 cd m^–2 and emission peak at 464 nm). Devices show a nearly 30-fold increase in operational stability compared with control LEDs, with a half-lifetime of 129 min at an initial luminance of 100 cd m^–2. Our findings demonstrate the performance of blue perovskite LEDs close to that of state-of-the-art blue organic LEDs and inorganic quantum dot LEDs and provide a new approach to design multifunctional molecules to boost the performance of perovskite optoelectronic devices.

钙钛矿发光二极管（LED）因其优异的发光性能和低成本而有望成为下一代显示器。尽管绿光和红光发射器件取得了实质性进展，但高效蓝光钙钛矿 LED 的开发仍然落后。在这里，我们展示了基于混合二维-三维钙钛矿和多功能离子添加剂的高效蓝色钙钛矿 LED，该添加剂能够控制降维相、非辐射复合通道和光谱稳定性。我们报道了一系列从混合溴化物/氯化物准三维区域发射高效电致发光的器件，外量子效率高达 21.4%（亮度为 22 cd m ^–2，发射峰值为 483 nm），13.2 %（亮度为 2.0 cd m ^{– 2}，发射峰值为 474 nm）和 7.3%（亮度为 6 cd m ^–2，发射峰值为 464 nm）。^{与对照 LED 相比，器件的运行稳定性提高了近 30 倍，初始亮度为 100 cd m –2}时半衰期为 129 分钟。我们的研究结果表明，蓝色钙钛矿 LED 的性能接近最先进的蓝色有机 LED 和无机量子点 LED，并提供了一种设计多功能分子以提高钙钛矿光电器件性能的新方法。