Aromatic Molecules Control Perovskite Quantum Dot Ripening for Efficient Solar Cells

High Resolution Image Download MS PowerPoint Slide Perovskite quantum dots (PQDs) combine solution processability with excellent optoelectronic properties for next-generation photovoltaics. However, ligand depletion across synthesis, purification, film formation, and storage accumulates surface defects that drive aggregation and Ostwald ripening of the PQDs. Meanwhile, long-chain oleic acid (OA)/oleylamine (OAm) ligands act as insulating barriers within PQD solids, inhibiting charge carrier transport and solar cell performance. Here, we introduce a ligand-assisted ripening control (LARC) strategy that fortifies aromatic-molecule binding on formamidinium lead triiodide (FAPbI 3 ) QDs to strengthen surface coordination and suppress ripening. Post-synthesis dosing with thiopheneacetic acid (TEAA) tunes the native OA/OAm acid–base equilibrium, facilitating proton exchange that drives controlled ligand desorption. The enhanced surface coordination suppresses ion detachment and breaks the dissolution–reprecipitation loop, thereby improving inter-QD electronic coupling. These synergistic effects yield FAPbI 3 QD-based solar cells with power conversion efficiencies up to 18.88% and enhanced stability under both humidity storage and standard one-sun operational conditions.