Abstract 

Metal halide perovskite light-emitting diodes (PeLEDs) show immense promise for next-generation lighting, display technologies, and visible light communication, but face significant challenges. Our research attempts to address these issues through innovative strategies. For green PeLEDs, we utilize interfacial chemistry-assisted in-situ growth of high-quality perovskite films, achieving ultra-low trap densities comparable to single-crystal films. This significantly enhances charge transport and minimizes interfacial emission quenching, leading to substantial improvements in brightness, operational lifetimes, and efficiency, with promising results also observed in lasing applications. Blue and white PeLEDs present additional challenges, such as stability, efficiency, and color purity. To address these, we introduce a self-assembled monolayer (SAM) with functional hole injection properties, significantly improving interfacial adhesion, reducing trap density, and optimizing energy levels. Furthermore, we achieve high-quality white PeLEDs using a downconversion approach. These advancements pave the way for brighter, more efficient, and faster-responding PeLEDs, expanding their potential applications in various fields, including visible light communication and lasing.