Role of Dielectric Drag in Polaron Mobility in Lead Halide Perovskites
ACS Energy Letters
American Chemical Society
© 2017 American Chemical Society
Reason for embargo
Under embargo until 7 October 2018 in compliance with publisher's policy
Hybrid organic-inorganic lead halide perovskites (HOIPs) have attracted much attention because of their remarkable carrier lifetimes and diffusion lengths. These properties have been attributed to the efficient screening of charge carriers via polaron formation in the highly polar and dynamic environment. Polaron formation explains, at least in part, the moderate charge carrier mobility, but the calculated mobilities are somewhat higher than experimental values. Here we discuss a factor that has been previously overlooked and can potentially account for the discrapency: the effect of dielectric drag. While optical phonon modes of the lead halide sublattice are mainly responsible for polaron formation, slower orientational relaxation of surrounding dipoles adds a dielectric drag to the moving charge. We discuss the role of this dielectric drag based on the measured dielectric function in the gigahertz to terahertz frequency range and how we can understand the unique carrier physics in HOIPs in view of its crystal-liquid duality.
We thank Prof. X. Roy, Dr. Johannes Hunger, Dr. Jarvist Frost, Prof. Shaul Mukamel, Prof. Casey Hynes, and Prof. Louis Brus for insightful discussions. X.Y.Z. thanks Profs. Song Jin, Vitaly Podzorov, and Filippo De Angelis for fruitful collaborations and his group, particularly Dr. Daniel Niesner, Dr. Xiaoxi Wu, Dr. Haiming Zhu, Dr. M. Tuan Trinh, Mr. Jue Wang, and Ms. Prakriti Joshi, for the experimental work which precipitated the ideas presented here. X.Y.Z. acknowledges U.S. Department of Energy, Office of Science - Basic Energy Sciences, Grant ER46980 for support during the writing of this Perspective. K.M. acknowledges JSPS for financial support.
This is the author accepted manuscript. The final version is available from American Chemical Society via the DOI in this record.
Vol. 2, Iss. 11, pp. 2555 - 2562