15.13% Sr-doped CsPbI₃ quantum dots with near-unity quantum yield via surface ligand compensation

Sr-doping of perovskite quantum dots (QDs) is a promising strategy to reduce Pb content and improve optical performance and stability. However, excessive Sr introduces new defects that degrade photoluminescence quantum yield (PLQY). Therefore, it is a challenge to balance high optical performance with high doping concentration for the preparation of environmentally friendly perovskite QDs. In this study, we report the highest Sr/Pb ratios Sr-doped CsPbI₃ QDs (15.13%) with a near-unity PLQY. The balance between high PLQY and high Sr-doping rate is achieved through the introduction of oleylammonium iodide (OAmI) ligand compensation during the anti-solvent purification process, which can form an iodine-enriched environment and effectively passivates the surface defects of QDs caused by excessive Sr-doping. Moreover, the Sr-doped CsPbI₃ QDs exhibit superior stability in environments with high temperature and humidity or direct contact with water. This strategy provides a novel approach for the preparation of lead-less and lead-free QDs with superior optical performance and stability, offering a potential solution for environmentally friendly applications.