Dual-site passivation by heterocycle functionalized amidinium cations toward high-performance inverted perovskite solar cells and modules

Abstract

Presently, most high-efficiency inverted perovskite solar cells (PSCs) are fabricated using toxic antisolvent and in a nitrogen-filled glovebox, which results in increased cost, reduced reproducibility, and incompatibility with large-area modules. In addition, interfacial trap-assisted nonradiative recombination impedes the further advancement of power conversion efficiency (PCE) and long-term operational stability of p–i–n inverted PSCs. Herein, we report a dual-site passivation of anionic and cationic defects through heterocycle functionalized amidinium cations, which stabilizes the interface between perovskite films and electron transport layers and minimizes interfacial nonradiative recombination loss. The dual-site passivation of amidinium cations is accomplished through precisely modulating the distance between two anchoring sites and spatial conformation. The dual-site passivation endows pyridine-functionalized amidinium salt 4-amidinopyridinium chloride (APCl) with an exceptional defect passivation ability. The APCl modulation enables high-efficiency inverted PSCs with a champion PCE of 26.83% (certified steady-state PCE of 26.32%), which is the best PCE ever reported for PSCs fabricated based on vacuum flash and in ambient air. The APCl-modulated devices could retain 95.8% of their initial performance after 2000 h of continuous maximum power point tracking. Moreover, the high-efficiency large-area module with a PCE of 19.83% (aperture area of 40.1 cm²) is obtained by this dual-site passivation technique of amidinium cations.