The authors present a method to enhance the current efficiency (CE) of perovskite light-emitting diodes (PeLEDs) by 20,000-fold, achieving a maximum CE of 42.9 cd A\(^{-1}\) and an external quantum efficiency (EQE) of 8.53%. They achieve this by modifying the stoichiometry of methylammonium bromide (MABr) to prevent the formation of metallic Pb atoms, which quench excitons, and by using nanocrystal pinning (NCP) to reduce the exciton diffusion length and spatially confine excitons within uniform MAPbBr\(_3\) nanograins. These modifications significantly increase the steady-state photoluminescence intensity and lifetime of the MAPbBr\(_3\) nanograin layers, leading to higher CE and EQE in PeLEDs. The study demonstrates a promising approach to overcome the efficiency limitations of PeLEDs, bringing them closer to the performance of phosphorescent OLEDs.The authors present a method to enhance the current efficiency (CE) of perovskite light-emitting diodes (PeLEDs) by 20,000-fold, achieving a maximum CE of 42.9 cd A\(^{-1}\) and an external quantum efficiency (EQE) of 8.53%. They achieve this by modifying the stoichiometry of methylammonium bromide (MABr) to prevent the formation of metallic Pb atoms, which quench excitons, and by using nanocrystal pinning (NCP) to reduce the exciton diffusion length and spatially confine excitons within uniform MAPbBr\(_3\) nanograins. These modifications significantly increase the steady-state photoluminescence intensity and lifetime of the MAPbBr\(_3\) nanograin layers, leading to higher CE and EQE in PeLEDs. The study demonstrates a promising approach to overcome the efficiency limitations of PeLEDs, bringing them closer to the performance of phosphorescent OLEDs.