Does Dipolar Motion of Organic Cations Affect Polaron Dynamics and Bimolecular Recombination in Halide Perovskites?

Autor:	Munson KT; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Swartzfager JR; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Gan J; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Asbury JB; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Jazyk:	angličtina
Zdroj:	The journal of physical chemistry letters [J Phys Chem Lett] 2020 Apr 16; Vol. 11 (8), pp. 3166-3172. Date of Electronic Publication: 2020 Apr 07.
DOI:	10.1021/acs.jpclett.0c00762
Abstrakt:	The role of dipolar motion of organic cations in the A-sites of halide perovskites has been debated in an effort to understand why these materials possess such remarkable properties. Here, we show that the dipolar motion of cations such as methylammonium (MA) or formamidinium (FA) versus cesium (Cs) does not influence large polaron binding energies, delocalization lengths, formation times, or bimolecular recombination lifetimes in lead bromide perovskites containing only one type of A-site cation. We directly probe the transient absorption spectra of large polarons throughout the entire mid-infrared and resolve their dynamics on time scales from sub-100 fs to sub-μs using time-resolved mid-infrared spectroscopy. Our findings suggest that the improved optoelectronic properties reported of halide perovskites with mixed A-site cations may result from synergy among the cations and how their mixture modulates the structure and dynamics of the inorganic lattice rather than from the dipolar properties of the cations themselves.
Databáze:	MEDLINE
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