Boosting the Operational Stability of Near-Infrared Perovskite LEDs Utilizing a Zinc Ion-Chelated Hybrid Electron-Transport Layer: The Critical Role of Interfacial Reactions
Near-infrared perovskite light-emitting diodes (NIR-PeLEDs) suffer from poor operational stability, largely due to interfacial reactions at the electron-transport layer (ETL)/perovskite interface. Here, we introduce a zinc ion (Zn2+)-chelated hybrid ETL derived from a Zn2+-chelated polyethylenimine ethoxylated (PEIE) complex, which partially retains the surface properties of ZnO but exhibits significantly reduced oxygen defects and surface-adsorbed hydroxyl groups. This well-modulated surface promotes perovskite crystallization and mitigates interface-induced deprotonation of organic cations during device operation. Consequently, NIR-PeLEDs employing this hybrid ETL achieve a peak external quantum efficiency (EQE) of 20.1%, a high radiance of 652 W sr-1 m-2, and an exceptional T50 lifetime of 270.7 hours at a high current density of 100 mA cm-2, which is over five times that of devices based on conventional ZnO nanocrystal (NC) ETLs. Our results present an effective ETL strategy for operationally stable NIR-PeLEDs and thoroughly reveal the critical role of regulating interfacial reactions in stabilizing buried interfacial contacts. These findings provide valuable insights for advancing perovskite optoelectronic devices that suffer from interface-induced performance degradation.