Elucidation of Chemical Species and Reactivity at Methylammonium Lead Iodide and Cesium Tin Bromide Perovskite Surfaces via Orthogonal Reaction Chemistry

• DOI: 10.1021/acs.jpcc.8b05352
• Publication Date: 2018-07-19T14:09:59Z
• Authors: Weiran Gao; Kenneth Zielinski; Benjamin N. Drury; Alexander D. Carl; Ronald L. Grimm
• Keywords: Reactivity

We quantified the chemical species present at and reactivity of (100) face tetrahedral single-crystal methylammonium lead iodide, MAPbI3(100), polycrystalline cesium tin bromide, CsSnBr3. For these ABX3 perovskites, experiments utilized orthogonal A+-site cation, B2+-site X–-site halide anion. Ambient pressure exposure to BF3 solutions probed interfacial halides. Reactions with p-trifluoromethylanilinium chloride exchange cation. A complex-forming ligand, 4,4′-bis(trifluoromethyl)-2,2′-bipyridine, for cations. Fluorine features in X-ray photoelectron spectroscopy (XPS) reaction outcomes each solution-phase species. XPS revealed adsorption BF3, indicating surface-available anions on both MAPbI3(100) Temperature-programmed desorption a ∼200 kJ mol–1 activation energy from ∼215 Adsorption fluorinated anilinium cation included no concomitant chlorine as by absence Cl 2p within limits detection. interpret observation exchanging surfaces CsSnBr3 surface. Within detection limits, bipyridine ligand demonstrated suggestive Pb2+ deficient surface, but that suggests surface-accessible Sn2+. The combination results implies cations iodide dominate tetragonal surface that, respectively, enables Lewis adduct formation derivatization. discuss context stability, passivation, perovskite-based conversion.