Metal halide perovskites are attracting a lot of attention as next-generation light-emitting materials owing to their excellent emission properties, with narrow band emission^1,2,3,4. However, perovskite light-emitting diodes (PeLEDs), irrespective of their material type (polycrystals or nanocrystals), have not realized high luminance, high efficiency and long lifetime simultaneously, as they are influenced by intrinsic limitations related to the trade-off of properties between charge transport and confinement in each type of perovskite material^5,6,7,8. Here, we report an ultra-bright, efficient and stable PeLED made of core/shell perovskite nanocrystals with a size of approximately 10 nm, obtained using a simple in situ reaction of benzylphosphonic acid (BPA) additive with three-dimensional (3D) polycrystalline perovskite films, without separate synthesis processes. During the reaction, large 3D crystals are split into nanocrystals and the BPA surrounds the nanocrystals, achieving strong carrier confinement. The BPA shell passivates the undercoordinated lead atoms by forming covalent bonds, and thereby greatly reduces the trap density while maintaining good charge-transport properties for the 3D perovskites. We demonstrate simultaneously efficient, bright and stable PeLEDs that have a maximum brightness of approximately 470,000 cd m⁻², maximum external quantum efficiency of 28.9% (average = 25.2 ± 1.6% over 40 devices), maximum current efficiency of 151 cd A⁻¹ and half-lifetime of 520 h at 1,000 cd m⁻² (estimated half-lifetime >30,000 h at 100 cd m⁻²). Our work sheds light on the possibility that PeLEDs can be commercialized in the future display industry.

金属卤化物钙钛矿作为下一代发光材料因其出色的发射性能和窄带发射^1,2,3,4而备受关注。然而，钙钛矿发光二极管 (PeLED)，无论其材料类型（多晶或纳米晶）如何，都没有同时实现高亮度、高效率和长寿命，因为它们受到与性能权衡相关的固有限制的影响每种钙钛矿材料中电荷传输和限制之间的关系^5,6,7,8. 在这里，我们报告了一种由核/壳钙钛矿纳米晶体制成的超亮、高效和稳定的 PeLED，尺寸约为 10 nm，是通过苄基膦酸 (BPA) 添加剂与三维 (3D) 多晶的简单原位反应获得的钙钛矿薄膜，无需单独的合成过程。在反应过程中，大的 3D 晶体分裂成纳米晶体，BPA 包围纳米晶体，实现强载流子限制。BPA 壳通过形成共价键钝化配位不足的铅原子，从而大大降低陷阱密度，同时保持 3D 钙钛矿良好的电荷传输性能。我们同时展示了高效、明亮和稳定的 PeLED，其最大亮度约为 470,000 cd m ^-2，最大外部量子效率为 28.9%（40 个器件的平均值 = 25.2 ± 1.6%），最大电流效率为 151 cd A ^{−1 ，在 1,000 cd m −2}时的半衰期为 520 h （估计半衰期 >30,000 h在 100 cd m ^-2）。我们的工作揭示了 PeLED 在未来显示行业中商业化的可能性。