Synergistic Passivation via Amino Acid Derivative for Highly Efficient Quasi-2D Perovskite Green Light-Emitting Diode

Quasi two-dimensional (2D) perovskite light-emitting diodes (PeLEDs) have emerged as promising candidates for next-generation displays and solid-state lighting. However, defects in the perovskite films often hinder the device performance of quasi-2D PeLEDs, leading to nonradiative recombination and efficiency losses. Herein, we introduce a novel synergistic passivation strategy using an amino acid derivative of Boc-N3-Cbz-L-2,3-diaminopropionic acid (BNCDA), with multiple C═O and N-H functional groups to passivate defects and suppress ion migration in perovskite films. By incorporating the passivation agent into the precursor solution, we significantly reduced the defect density and enhanced radiative recombination. As a result, the optimized PeLEDs demonstrate a remarkable external quantum efficiency (EQE) of 22.6% and a maximum luminance of 57951 cd m^-2 for 511 nm emission. Simultaneously, the optimal devices display superior spectral stability and an enhanced operation lifetime in ambient air. This work highlights the importance of the synergistic effect in effectively passivating defects in quasi-2D PeLEDs and provides an interesting way to select passivating molecules for fabricating high-performance PeLEDs for future display and lighting applications.