Direct optical patterning of CsPbBr3 quantum dots with zwitterionic photocrosslinkable ligand

Direct optical patterning of perovskite colloidal quantum dots (QDs) mediated by surface chemistry has emerged as a critical focus for new display technologies. However, the instability of weakly bound ligands on QD surfaces significantly restricts their practical applications. To address this challenge, we propose a novel and straightforward strategy that utilizes the strongly binding zwitterionic photocrosslinkable ligand 2-methacryloyloxyethyl phosphorylcholine (MPC) via ligand exchange, enabling direct optical patterning of CsPbBr 3 QDs without requiring an inert environment or precise ultraviolet (UV) light intensity control. The MPC ligand exhibits dual functionality: it effectively passivates QD surface defects, achieving a photoluminescence quantum yield (PLQY) of 83.8 ± 1.4 % for CsPbBr 3 QD colloidal solutions, while simultaneously enabling direct optical patterning in ambient air. This patterning mechanism relies on methacrylate groups that initiate polymerization upon UV irradiation, forming a robust crosslinked network. The resulting patterns exhibit a high PLQY of 72.5 ± 5.9 %. Additionally, theoretical calculations reveal that the planar orientation of MPC ligands on the QD surface minimizes inter-QD spacing, promoting the formation of dense and smooth films. This innovative approach not only enhances the optical performance of CsPbBr 3 QDs but also paves the way for their practical implementation in high-quality, vivid image displays.