Enhancing Photoluminescence and Stability of CsPbI3 Perovskite Quantum Dots via Cysteine Post-Processing

Red-emitting cesium lead iodide (CsPbI3) perovskite quantum dots (CQDs) are extremely unstable due to their structural composition and the weak binding force of ligands on the surface of nanocrystals. Herein, we report an effective method to enhance the photoluminescence and stability of CQDs by simple post-processing with cysteine (Cys). Compared to the pristine CQDs with a photoluminescence quantum yield (PLQY) of 38.61%, the Cys-processed one has fewer surface defects, obtaining a PLQY of 70.77%, nearly twice as much as the pristine samples, and, simultaneously, the Cys-processed CQDs retained more than 86% of the initial PL intensity after 20 days of storage in the atmosphere. This research provides a new idea for the preparation of high-performance and red-emitting quantum dots.