Complementary Dual‐Ligands Resurfacing CsPbI <sub>3</sub> Perovskite Quantum Dots for High‐Performance Solar Cells
Xinyi Mei, Bainian Ren, Junming Qiu, Zhimei Sun, Xiaoliang Zhang
Abstract
perovskite quantum dots (PQDs) emerge as promising optoelectronic materials for photovoltaics due to their high photoluminescence quantum yields and solution processability. However, the dynamic binding of long-chain ligands on the PQD surface generally induces numerous surface defects, which severely degrade the optoelectronic properties and stability of PQDs, to a large extent limiting the photovoltaic performance and operational stability of PQD solar cells (PQDSCs). Herein, a complementary dual-ligand reconstruction strategy is proposed to resurface the PQDs, in which the trimethyloxonium tetrafluoroborate and phenylethyl ammonium iodide can form a complementary dual-ligand system on the PQD surface through hydrogen bonds. The results reveal that the complementary dual-ligand system can not only stabilize the surface lattice of PQDs maintaining their good dispersion in the colloidal solution but also largely improve the inter-dot electronic coupling in the PQD solids. As a consequence, the PQDs demonstrate substantially improved optoelectronic properties and environmental stability, as well as a more uniform stacking orientation in the PQD solids, leading to a record high efficiency of up to 17.61% being realized in inorganic PQDSCs. This work provides a new avenue for the surface ligand engineering of PQDs for high-performance optoelectronic devices.