Multi-Functional Interface-Driven Defect Passivation Enabling High Efficiency and Stability in Vacuum-Processed Perovskite Light-Emitting Diodes

Abstract

Vacuum-processed perovskite light-emitting diodes (PeLEDs) hold great promise for large-area, high-resolution display technologies owing to their compatibility with scalable patterning and fabrication processes. However, their performance has been constrained by interfacial defects that induce non-radiative recombination losses. Herein, we demonstrate highly efficient and stable CsPbBr3-based PeLEDs fabricated via evaporation through a multi-functional interfacial engineering strategy that enables comprehensive defect passivation. A synergistic combination of phenylethylammonium bromide (PEABr), lithium bromide (LiBr), and (2-(3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (Br-2PACz) is introduced to concurrently suppress halide vacancies, modulate crystallization kinetics, and passivate trap states in perovskite. Time-resolved photoluminescence and space-charge-limited current analyses further confirm the prolonged exciton lifetime and reduced defect density. This cooperative effect enhances radiative recombination and carrier balance, resulting in a record external quantum efficiency (EQE) of 9.46% and a peak luminance of 21,931cd m−2, representing ∼135- and 49-fold improvements compared with the pristine device (0.07% EQE and 446.7cd m−2). Moreover, the optimized PeLED exhibits a 15.8-fold increase in operational lifetime (from 15.5 to 245.7min at 100cd m−2) and markedly reduced current hysteresis, attributed to suppressed ion migration and stabilized interfacial energetics. This work highlights an effective pathway toward realizing vacuum-processed, high-performance perovskite emitters through rational multi-functional interface design. © 2026 Wiley-VCH GmbH.