Lead-Halide Scalar Couplings in 207Pb NMR of APbX3 Perovskites (A = Cs, Methylammonium, Formamidinium; X = Cl, Br, I)

Marcel Aebli; Laura Piveteau; Olga Nazarenko; Bogdan M Benin; Franziska Krieg; René Verel; Maksym V Kovalenko

doi:10.1038/s41598-020-65071-4

Lead-Halide Scalar Couplings in ²⁰⁷Pb NMR of APbX₃ Perovskites (A = Cs, Methylammonium, Formamidinium; X = Cl, Br, I)

Sci Rep. 2020 May 19;10(1):8229. doi: 10.1038/s41598-020-65071-4.

Authors

Marcel Aebli^{1

2}, Laura Piveteau^{1

2

3}, Olga Nazarenko^{1

2}, Bogdan M Benin^{1

2}, Franziska Krieg^{1

2}, René Verel⁴, Maksym V Kovalenko^{5

6}

Affiliations

¹ Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093, Switzerland.
² Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Überlandstrasse 129, CH-8600, Switzerland.
³ Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHTI), UPR 3079 CNRS, Université d'Orléans, 1D Avenue de la Recherche Scientifique, 45071, Orléans, France.
⁴ Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093, Switzerland. verelr@ethz.ch.
⁵ Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, CH-8093, Switzerland. mvkovalenko@ethz.ch.
⁶ Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Überlandstrasse 129, CH-8600, Switzerland. mvkovalenko@ethz.ch.

Abstract

Understanding the structure and dynamics of newcomer optoelectronic materials - lead halide perovskites APbX₃ [A = Cs, methylammonium (CH₃NH₃⁺, MA), formamidinium (CH(NH₂)₂⁺, FA); X = Cl, Br, I] - has been a major research thrust. In this work, new insights could be gained by using ²⁰⁷Pb solid-state nuclear magnetic resonance (NMR) spectroscopy at variable temperatures between 100 and 300 K. The existence of scalar couplings ¹J_Pb-Cl of ca. 400 Hz and ¹J_Pb-Br of ca. 2.3 kHz could be confirmed for MAPbX₃ and CsPbX₃. Diverse and fast structure dynamics, including rotations of A-cations, harmonic and anharmonic vibrations of the lead-halide framework and ionic mobility, affect the resolution of the coupling pattern. ²⁰⁷Pb NMR can therefore be used to detect the structural disorder and phase transitions. Furthermore, by comparing bulk and nanocrystalline CsPbBr₃ a greater structural disorder of the PbBr₆-octahedra had been confirmed in a nanoscale counterpart, not readily captured by diffraction-based techniques.