LAUSR

Abstract The highly stable and efficient perovskite light-emitting diodes (PeLEDs) via applying an insulating layer of polyethylenimine ethoxylated (PEIE) are fabricated. The PeLED consisted of an ultrathin PEIE layer exhibits 90.6% of initial maximum luminance after 2 h and can still emit light after 8 days. Meanwhile, by realizing the morphology improvement of MAPbBr 3 and more balanced charge injection of perovskite film, a high efficiency PeLEDs with a maximum luminance of 914.5 cd/m 2 and a maximum current efficiency of 0.28 cd/A at a bias of 8.1 V are achieved. This work not only proposes a concise and effective approach for the significant improvement of PeLEDs stability, but also opens a high potential route for the practical application of high efficiency PeLEDs.