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Coupling methylammonium and formamidinium cations with halide anions: Hybrid orbitals, hydrogen bonding, and the role of dynamics

Kamal, C.; Weinhardt, L.; Odelius, M.; Hauschild, D.; Seitz, L.; Steininger, R.; Yang, W.; Heske, C.


The electronic structures of four precursors for organic–inorganic hybrid perovskites, namely, methylammonium chloride and iodide, as well as formamidinium bromide and iodide, are investigated by X-ray emission (XE) spectroscopy at the carbon and nitrogen K-edges. The XE spectra are analyzed based on density functional theory calculations. We simulate the XE spectra at the Kohn–Sham level for ground-state geometries and carry out detailed analyses of the molecular orbitals and the electronic density of states to give a thorough understanding of the spectra. Major parts of the spectra can be described by the model of the corresponding isolated organic cation, whereas high-emission energy peaks in the nitrogen K-edge XE spectra arise from electronic transitions involving hybrids of the molecular and atomic orbitals of the cations and halides, respectively. We find that the interaction of the methylammonium cation is stronger with the chlorine than with the iodine anion. Furthermore, our detailed theoretical analysis highlights the strong influence of ultrafast proton dynamics in the core-excited states, which is an intrinsic effect of the XE process. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000140546
Veröffentlicht am 03.12.2021
DOI: 10.1021/acs.jpcc.1c08932
Zitationen: 1
Web of Science
Zitationen: 1
Zitationen: 1
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Photonenforschung und Synchrotronstrahlung (IPS)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1932-7447, 1932-7455
KITopen-ID: 1000140546
HGF-Programm 56.12.11 (POF IV, LK 01) Materials - Quantum, Complex and Functional
Erschienen in Journal of Physical Chemistry C
Verlag American Chemical Society (ACS)
Band 125
Heft 46
Seiten 25917–25926
Vorab online veröffentlicht am 11.11.2021
Nachgewiesen in Dimensions
Web of Science
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