Influence of chloride substitution on the rotational dynamics of methylammonium in MAPbI(3-x)Cl(x) perovskites
- Hybrid halide perovskites, MAPbI(3), MAPbI(2.94)Cl(0.0)6, and MAPbCl(3) (MA, methylammonium), were investigated using inelastic and quasielastic neutron scattering (QENS) with the aim of elucidating the impact of chloride substitution on the rotational dynamics of MA. In this context, we discuss the influence of the inelastic neutron scattering caused by low-energy phonons on QENS, resulting from the MA rotational dynamics in MAPbI(3-x)Cl(x). Through a comparative temperature-dependent QENS investigation with different energy resolutions, which allow a wide Fourier time window, we achieved a consistent description of the influence of chlorine substitution in MAPbI(3) on the MA dynamics. Our results showed that chlorine substitution in the low-temperature orthorhombic phase leads to a weakening of the hydrogen bridge bonds, since the characteristic relaxation times of C-3 rotation at 70 K in MAPbCl(3) (135 ps) and MAPbI(2.94)Cl(0.06) (485 ps) are much shorter than that in MAPbI(3) (1635 ps). For the orthorhombic phase, we obtained theHybrid halide perovskites, MAPbI(3), MAPbI(2.94)Cl(0.0)6, and MAPbCl(3) (MA, methylammonium), were investigated using inelastic and quasielastic neutron scattering (QENS) with the aim of elucidating the impact of chloride substitution on the rotational dynamics of MA. In this context, we discuss the influence of the inelastic neutron scattering caused by low-energy phonons on QENS, resulting from the MA rotational dynamics in MAPbI(3-x)Cl(x). Through a comparative temperature-dependent QENS investigation with different energy resolutions, which allow a wide Fourier time window, we achieved a consistent description of the influence of chlorine substitution in MAPbI(3) on the MA dynamics. Our results showed that chlorine substitution in the low-temperature orthorhombic phase leads to a weakening of the hydrogen bridge bonds, since the characteristic relaxation times of C-3 rotation at 70 K in MAPbCl(3) (135 ps) and MAPbI(2.94)Cl(0.06) (485 ps) are much shorter than that in MAPbI(3) (1635 ps). For the orthorhombic phase, we obtained the activitin energies from the temperature-dependent characteristic relaxation times tau (c3). by Arrhenius fits, indicating lower values of E-a for MAPbCl(3) and MAPbI(2.94)Cl(0.06) compared to that of MAPbI(3). We also performed QENS analyses at 190 K for all three samples. Here, we observed that MAPbCI(3) shows slower MA rotational dynamics than MAPbI(3) in the disordered structure.…
Author details: | Götz SchuckORCiDGND, Frederike LehmannORCiD, Jacques OllivierORCiD, Hannu MutkaORCiD, Susan SchorrORCiDGND |
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DOI: | https://doi.org/10.1021/acs.jpcc.9b01238 |
ISSN: | 1932-7447 |
Title of parent work (English): | The journal of physical chemistry : C, Nanomaterials and interfaces |
Publisher: | American Chemical Society |
Place of publishing: | Washington |
Publication type: | Article |
Language: | English |
Date of first publication: | 2019/04/16 |
Publication year: | 2019 |
Release date: | 2021/02/08 |
Volume: | 123 |
Issue: | 18 |
Number of pages: | 11 |
First page: | 11436 |
Last Page: | 11446 |
Funding institution: | HyPerCell (Hybrid Perovskite Solar Cells) joint Graduate School |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |