Highly Efficient Pure‐Red Quasi‐2D Perovskite Light‐Emitting Diodes Enabled by Propylammonium Chloride Passivator

Perovskite light-emitting diodes (PeLEDs) based on quasi-2D perovskites have attracted great attention in the past few years. Although significant achievements are made in device performance, fabrication of high-efficiency PeLEDs with pure-red (620-635 nm) light emission remains a significant challenge, which inhibits their practical application for full-color displays. Herein, a series of efficient red PeLEDs at 625 nm are realized by employing volatile alkylammonium chlorides (propylammonium chloride) passivators. The interaction of PbI2 with propylamine (PA) horizontal ellipsis H+Cl- in the precursor solution effectively passivates the defects, leading to reduced non-radiative recombination and enhanced device performance. By optimizing the amount of PACl, an external quantum efficiency (EQE) of 16.1% and a maximum brightness of 1701 cd m-2 are achieved, among the best-performing quasi-2D I-based PeLEDs with emissions ranging from 620 to 635 nm. This work provides a new route to improve the stability and efficiency of pure-red PeLEDs. Efficient quasi-2D red PeLEDs at 625 nm are realized by employing volatile alkylammonium chlorides (propylammonium chloride) passivators. The interaction of PbI2 with propylamine (PA) horizontal ellipsis H+Cl- effectively passivates the defects, leading to reduced non-radiative recombination and improved carrier transfer. Consequently, the PACl-treated devices achieve the highest external quantum efficiency (EQE) of 16.1% for quasi-2D I-based pure-red PeLEDs. image