Li, YangMilic, Jovana V.Ummadisingu, AmitaSeo, Ji-YounIm, Jeong-HyeokKim, Hui-SeoLiu, YuhangDar, M. IbrahimZakeeruddin, Shaik M.Wang, PengHagfeldt, AndersGratzel, Michael2019-02-012019-02-012019-02-012019-01-0110.1021/acs.nanolett.8b03552https://infoscience.epfl.ch/handle/20.500.14299/154293WOS:000455561300018Three-dimensional (3D) perovskite materials display remarkable potential in photovoltaics owing to their superior solar-to-electric power conversion efficiency, with current efforts focused on improving stability. Two-dimensional (2D) perovskite analogues feature greater stability toward environmental factors, such as moisture, owing to a hydrophobic organic cation that acts as a spacer between the inorganic layers, which offers a significant advantage over their comparatively less stable 3D analogues. Here, we demonstrate the first example of a formamidinium (FA) containing Dion Jacobson 2D perovskite material characterized by the BFA(n-1)Pb(n)I(3n+1) formulation through employing a novel bifunctional organic spacer (B), namely 1,4-phenyl-enedimethanammonium (PDMA). We achieve remarkable efficiencies exceeding 7% for (PDMA)-FA(2)Pb(3)I(10) based 2D perovskite solar cells resisting degradation when exposed to humid ambient air, which opens up new avenues in the design of stable perovskite materials.Chemistry, MultidisciplinaryChemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinaryPhysics, AppliedPhysics, Condensed MatterChemistryScience & Technology - Other TopicsMaterials SciencePhysicstwo-dimensional perovskiteslayered perovskitesbifunctional spacersmolecular designlightmigrationdegradationtext::journal::journal article::research article