Awais, MuhammadKundu, SoumyaZhang, DongyangYeddu, VishalKokaba, Mohammad RezaAhmed, YameenZhou, WenDayneko, SergeyTan, FuruiSaidaminov, Makhsud I.2024-01-232024-01-2320232023Awais, M., Kundu, S., Zhang, D., Yeddu, V., Kokaba, M. R., Ahmed, Y., ... Saidaminov, M. I. (2023). Selective deactivation of perovskite grain boundaries. Cell Reports Physical Science, 4(10), 101634. https://doi.org/10.1016/j.xcrp.2023.101634https://doi.org/10.1016/j.xcrp.2023.101634http://hdl.handle.net/1828/15848Grain boundaries in perovskites are a major source of degradation in perovskite solar cells. Here, we report selective passivation of perovskite grain boundaries with the aid of biphenyl-containing moieties. We find that biphenyl ligands selectively react with PbI2-rich interfaces but not with perovskite itself. Such targeted defect deactivation of grain boundaries leads to extended radiative recombination lifetime from 1 to 2.7 μs while allowing for efficient charge transfer from grains. The hydrophobic nature of benzene ring present in biphenyl improves the stability of perovskite in direct reaction with water by a factor of 3. The devices, all fabricated in ambient air, show significantly improved reproducibility (17%–21% efficiency) and increased open-circuit voltage of 1.11 V. This work offers a design principle for selective passivation of grain boundaries and chemical stabilization of hybrid structures.enperovskite solar cellssurface passivation4-phenylbenzylammonium iodidebiphenyl methylammonium iodideArticleDepartment of Electrical and Computer EngineeringDepartment of Chemistry