Title: Coupling Methylammonium and Formamidinium Cations with Halide Anions: Hybrid Orbitals, Hydrogen Bonding, and the Role of Dynamics

Abstract

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. The inclusion of this effect is necessary for an accurate description of the experimental nitrogen K-edge X-ray emission spectra and gives information on the hydrogen-bonding strengths in the differentmore » precursor materials.« less

Authors:

Kamal, Chinnathambi  ^[1];

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Hauschild, Dirk  ^[2];

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Seitz, Linsey  ^[3];

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Steininger, Ralph ^[4]; Yang, Wanli  ^[5];

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Heske, Clemens  ^[2];

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Weinhardt, Lothar  ^[2];

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Odelius, Michael  ^[6]

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+ Show Author Affiliations

1. Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden, Theory and Simulations Laboratory, HRDS, Raja Ramanna Centre for Advanced Technology, Indore 452013, India, Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
2. Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany, Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany, Department of Chemistry and Biochemistry, University of Nevada Las Vegas (UNLV), Las Vegas, Nevada 89154-4003, United States
3. Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany, Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
4. Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany
5. Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
6. Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden

Publication Date:

2021-11-11

Research Org.:

Stockholm Univ. (Sweden); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1829948

Alternate Identifier(s):

OSTI ID: 1832875; OSTI ID: 1845110

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Name: Journal of Physical Chemistry. C Journal Volume: 125 Journal Issue: 46; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Energy; Inorganic compounds; Mathematical methods; Cations; Halogens; energy; inorganic compounds; mathematical methods; cations; halogens