Unlocking Subunit Cell Precision Overgrowth in CsPbBr ₃ Quantum Dots

Perovskite quantum dots (pQDs) combine highly tunable optical properties with facile solution-phase synthesis, transforming both classical and quantum light-driven applications. However, heterogeneous overgrowth in pQDs remains challenging, especially for small QDs (<10 nm). Here, we demonstrate the precision overgrowth of CsPbBr₃ QD seeds using stepwise injection and quasi-continuous precursor injections. We found that higher ligand coordination suppresses burst nucleation and directs the reaction toward heterogeneous nucleation, allowing for submonolayer thickness control. Together, these insights outline how ligand strength, monomer availability, and thermal energy collectively govern overgrowth behavior, providing a clear design framework for the controlled synthesis of colloidal perovskites.