Suppressing nonradiative recombination enables highly efficient red perovskite light-emitting diodes.

An effective defect passivation strategy is demonstrated by introducing the diethylene glycol bis(3-aminopropyl) ether (DGBE) additive to suppress the non-radiative recombination. Thus, high-performance red PeLEDs are realized with a maximum EQE of 24.2%, which provides a rational strategy for boosting the performance of red PeLEDs. [Display omitted] • The defect-induced nonradiative recombination is effectively suppressed by introducing the Lewis base additive of diethylene glycol bis(3-aminopropyl) ether (DGBE). • The PLQYs of the DGBE-modified perovskite films significantly increase from 39% to 80%. • High color purity and efficient red PeLEDs is achieved with a maximum EQE of 24.2%, representing one of the best performing red PeLEDs reported so far. • This work provides a reliable approach to promote the development of highly efficient red PeLEDs. Quasi-two-dimensional perovskites are promising emitters for red light-emitting diodes. However, the practical application of red perovskite light-emitting diodes (PeLEDs) is still limited by the defect-induced nonradiative recombination. In this study, we demonstrate efficient red PeLEDs by introducing the diethylene glycol bis(3-aminopropyl) ether (DGBE) additive. The coupling effect between oxygen (O) atoms in DGBE and unsaturated Pb2+ not only regulates crystallization, but also passivates defects. Benefiting from the reduced defect densities and enhanced radiative recombination efficiencies, the photoluminescence quantum yield (PLQY) increases from 39 % to 80 %. Consequently, we achieve high-performance red PeLEDs with a maximum external quantum efficiency of 24.2 %, which provides a reliable approach to promote the development of highly efficient red PeLEDs. [ABSTRACT FROM AUTHOR]