Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse colloidal particles (confining electrons and holes, and boosting radiative recombination) with fewer surface defects (reducing non-radiative recombination). Doping of guanidinium into formamidinium lead bromide PNCs yields limited bulk solubility while creating an entropy-stabilized phase in the PNCs and leading to smaller PNCs with more carrier confinement. The extra guanidinium segregates to the surface and stabilizes the undercoordinated sites. Furthermore, a surface-stabilizing 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene was applied as a bromide vacancy healing agent. The result is highly efficient PNC-based light-emitting diodes that have current efficiency of 108 cd A⁻¹ (external quantum efficiency of 23.4%), which rises to 205 cd A⁻¹ (external quantum efficiency of 45.5%) with a hemispherical lens.

金属卤化物钙钛矿纳米晶体 (PNC) 的电致发光效率受到缺乏既能抑制缺陷形成又能增强电荷载流子限制的材料策略的限制。在这里，我们报告了一种单掺杂合金化策略，该策略可以生成更小的、单分散的胶体颗粒（限制电子和空穴，并促进辐射复合），同时具有更少的表面缺陷（减少非辐射复合）。将胍掺杂到甲脒溴化铅 PNC 中会产生有限的体积溶解度，同时在 PNC 中产生熵稳定相，并导致更小的 PNC 具有更多的载流子限制。额外的胍分离到表面并稳定了配位不足的位点。此外，表面稳定的 1,3,5-三（溴甲基）-2,4，6-三乙苯用作溴化物空位愈合剂。结果是高效的基于 PNC 的发光二极管，其电流效率为 108 cd A^-1（外部量子效率为 23.4%），使用半球形透镜可升至 205 cd A ^-1（外部量子效率为 45.5%）。