Advancements and challenges in post-treatment anion exchange process for high-performance perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) are rapidly evolving for next-generation display technologies, owing to their facile solution-processing, high luminous efficiency and exceptional color purity. Although significant progress has been achieved in near-infrared, red, and green PeLEDs, however, the performance of deep-blue PeLEDs lags significantly behind due to halide segregation, poor solubility of inorganic chlorides, and low photoluminescence quantum yields. To address these challenges, the Post-Treatment Anion Exchange (PTAE) method has emerged as a novel approach for developing high-performance deep-blue PeLEDs. This work focuses on recent advancements in PTAE-treated PeLEDs, highlighting different strategies for the generation of Cl⁻ ions. The impacts of cation size on film morphology and optoelectronic properties and the underlying halide exchange kinetics are analyzed. This review highlights the application of the PTAE method for producing bright and stable red, green, and blue emissions essential to multi-color display technologies. It investigates the importance of thorough improvement of the PTAE technique and advancing the understanding of the halide exchange mechanism. The review also outlines key challenges and proposes future research directions to tackle with them. Overall, this work aims to serve as a valuable resource and to inspire researchers in condensed matter physics, materials science, and solid-state chemistry.