5-Chloro-2-Hydroxypyridine Derivatives with Push-Pull Electron Structure Enable Durable and Efficient Perovskite Solar Cells

Abstract

Targeted passivation of defects in perovskite is the primary consideration in the design of additives containing functional groups. However, the precise modulation of electron structure in functional groups and the structure-activity relationship between electronic configuration and performance of perovskite solar cells (PSCs) still need to be explored. In this study, 5-chloro-2-hydroxypyridine derivatives with –NH2 (HNCLP) and –F (HFCLP) end groups are selected to realize the push-pull electronic structure configuration. Density functional theory demonstrates that, compared with HFCLP, HNCLP with the electron-donating terminal of –NH2 has a long dipole moment and immobilize the interstitial I3−, and the N side of pyridine with high-density electron cloud enables strong passivation with undercoordinated Pb2+ ions. The experimental results confirm that HNCLP with optimized electronic configuration emerges strong passivation ability, greatly suppresses the nonradiative recombination of perovskite absorber, and remarkably improves the film crystal quality along with the extraction and transfer process of photogenerated carriers. The HNCLP-contained PSC exhibits a remarkable efficiency of 24.47%, and HNCLP helps to enhance the moisture-proof of perovskite film and device storage stability.