Multidentate passivation crosslinking perovskite quantum dots for efficient solar cells

The surface ligand chemistry is vital to diminish surface defects and improve the electronic coupling of perovskite quantum dots (PQDs) toward emerging applications in optoelectronic devices. Herein, we report a “surface surgery treatment” of PQDs using multidentate ligands, ethylene diamine tetraacetic acid (EDTA), for resurfacing PQDs. The results reveal that the EDTA could not only peel the suspended Pb²⁺ ions from the PQD surface but also effectively passivate the surface defects of PQDs by occupying I^- vacancies. Meanwhile, the EDTA could also crosslink PQDs as a charger bridge to improve the electronic coupling of PQDs. Consequently, the charge carrier transport within the PQD solid films is substantially improved with suppressed nonradiative recombination, boosting the efficiency of up to 15.25% in inorganic PQD solar cells (PQDSCs), among the highest efficiencies of inorganic PQDSCs realized by regulating surface ligands of PQDs. This work provides a distinctive understanding of the surface functionalization of PQDs to improve their optoelectronic properties for application in high-performance optoelectronic devices.