Enhanced Performance of ZnO-Based Deep Red Perovskite Light-Emitting Diodes through Polyethylenimine Ethoxylated/1- Aminopyridinium Iodide Dual-Function Modification Layer

Deep red perovskite light-emitting diodes (LEDs) based on a zinc oxide (ZnO) electron transporting layer (ETL) have achieved great improvement in recent years. Polyethylenimine ethoxylated (PEIE) is widely employed as a modification layer for ZnO in deep red perovskite LEDs to address the interfacial reaction between ZnO and perovskites. However, there is a lack of research on the regulation of the PEIE properties. In this work, we design a dual-function modification layer of PEIE doped with 1-aminopyridinium iodide (PyNI) to achieve improved energy level alignment and enhanced perovskite film quality. As a result, the deep red perovskite LEDs with a PEIE/PyNI dual-function modification layer exhibit a peak external quantum efficiency of 17.5%, a brightness of 1644 cd m^–2, and extended operational stability (T₅₀ = 8.3 h at 20 mA cm^–2). These advancements highlight the critical role of ZnO surface modification in achieving high-performance ZnO-based deep red perovskite LEDs.