Surface Lattice‐Adaptive Integrity Reconstruction of Perovskite Quantum Dots for Efficient Solar Cells

Formamidinium lead triiodide perovskite quantum dots (FAPbI 3 PQDs) receive increasing attention for next‐generation solar cells owing to their remarkable optoelectronic properties and solution processability. However, the dynamic binding of native surface ligands inevitably induces surface lattice vacancies and distortions, significantly deteriorating the optoelectronic properties and stability of PQDs. Herein, a facile surface lattice‐adaptive integrity reconstruction strategy is reported to regulate the surface lattice of PQDs. After molecule screening, the 3‐guanidinopropionic acid (GPA) with a geometry‐adaptive configuration can effectively passivate the intrinsic surface lattice vacancies through the Pb‐O coordination and guanidinium‐mediated hydrogen‐bonding interactions. Meanwhile, the surface lattice‐adaptive configuration of the GPA can also substantially ameliorate the distorted surface lattice, which largely improves the surface lattice integrity and enhances the electronic coupling of PQDs, facilitating charge carrier transport in the PQD solids. Consequently, the power conversion efficiency is increased from 16.15% for the control solar cell to 19.32% for the GPA‐based solar cell. This work provides important insight into the physical design principles for the surface lattice of PQDs through lattice‐adaptive molecules and offers implementable strategies for the development of high‐performance optoelectronic devices.