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Mechanistic Insight into the Attachment of Fullerene Derivatives on Crystal Faces of Methylammonium Lead Iodide Based Perovskites
journal contribution
posted on 2016-09-07, 00:00 authored by M. F.
N. Taufique, S. M. Mortuza, Soumik BanerjeeRecent studies suggest that electron
transport layers (ETLs) comprising
[6,6]-phenyl-C61-butyric acid methyl ester (PCBM), employed in planar
perovskite solar cells, reduce hysteresis by passivating the deep
trap states, thereby underscoring the importance of interfacial structures.
To gain physical insights into the PCBM–perovskite interfaces
during solution processing, we performed molecular dynamics simulations
of PCBMs solvated in chlorobenzene near (110) and (100) perovskite
surfaces. Our results indicate strong orientational preferences of
deposited PCBMs with the strongest associations between the carbonyl
oxygen atom of PCBM and the terminating Pb and H atoms of (110) and
(100) faces of perovskite, respectively. The phenyl moiety shows weak
associations with the (100) perovskite surface enabling two-pronged
anchoring that might facilitate charge transfer. In-plane ordering
of PCBMs on perovskite surfaces indicates that a more densely packed
monolayer is formed on the (110) surface compared to that on the (100)
surface and might lead to more efficient electron transport.