Cation Dynamics in Mixed-Cation (MA)x(FA)1-xPbI3 Hybrid Perovskites from Solid-State NMR

Dominik J Kubicki; Daniel Prochowicz; Albert Hofstetter; Péter Péchy; Shaik M Zakeeruddin; Michael Grätzel; Lyndon Emsley

doi:10.1021/jacs.7b04930

Cation Dynamics in Mixed-Cation (MA)_x(FA)_1-xPbI₃ Hybrid Perovskites from Solid-State NMR

J Am Chem Soc. 2017 Jul 26;139(29):10055-10061. doi: 10.1021/jacs.7b04930. Epub 2017 Jul 11.

Authors

Dominik J Kubicki¹, Daniel Prochowicz^{2

3}, Albert Hofstetter¹, Péter Péchy², Shaik M Zakeeruddin², Michael Grätzel², Lyndon Emsley¹

Affiliations

¹ Laboratory of Magnetic Resonance, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
² Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne, Switzerland.
³ Institute of Physical Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.

PMID: 28641413
DOI: 10.1021/jacs.7b04930

Abstract

Mixed-cation organic lead halide perovskites attract unfaltering attention owing to their excellent photovoltaic properties. Currently, the best performing perovskite materials contain multiple cations and provide power conversion efficiencies up to around 22%. Here, we report the first quantitative, cation-specific data on cation reorientation dynamics in hybrid mixed-cation formamidinium (FA)/methylammonium (MA) lead halide perovskites. We use ¹⁴N, ²H, ¹³C, and ¹H solid-state MAS NMR to elucidate cation reorientation dynamics, microscopic phase composition, and the MA/FA ratio, in (MA)_x(FA)_1-xPbI₃ between 100 and 330 K. The reorientation rates correlate in a striking manner with the carrier lifetimes previously reported for these materials and provide evidence of the polaronic nature of charge carriers in PV perovskites.

Publication types

Research Support, Non-U.S. Gov't