Electrical properties of carbon-based fully-printed mesoscopic perovskite solar cells with BAI as an additive

Carbon-based mesoscopic perovskite solar cells (MPSCs) usually suffer from severe defects-induced carrier recombination loss caused by the poor crystal quality of perovskite in the triple-mesoporous architecture. Herein, carbon-based MPSCs are fabricated via one-step drop-casting a mixed perovskite precursor solution of MAPbI₃ and benzylamine hydroiodide (BAI). BAI-MAPbI₃ MPSCs achieve a high PCE of 12.7%, which is nearly two times superior to 6.4% of pristine MAPbI₃ devices. Systematic studies have found that the introduction of BAI not only reduces defect concentration in perovskite films but also induces sufficient pore filling in the triple-mesoporous architecture and better interface contact between perovskite and TiO₂ layers, and increases the carrier lifetime of photo-generate charges in BAI-MAPbI₃ MPSCs. Additionally, BAI-MAPbI₃ MPSCs show improved operational stability by maintaining more than 50% of the original PCE after 5000 min continuous light irradiation in ambient air. These results indicate that BAI is an effective additive for carbon-based MPSCs. This facile additive strategy opens a promising direction for further developing carbon-based MPSCs.