Electron-phonon coupling and polaron mobility in hybrid perovskites from first-principles
2017-09-11T21:54:12Z (GMT) by
Density functional theory electronic structures, maximally localized Wannier funcitons and linear response theory are used to compute the electron and hole mobility of both inorganic, Cs-containing, and hybrid, CH<sub>3</sub>NH<sub>3</sub>-containing, lead bromide perovskites. When only phonon scattering is considered we find hole mobilities at room temperature in the 40-180~cm<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup> range, in good agreement with experimental data for highly-ordered crystals. The electron mobility is about an order of magnitude larger, because low-energy phonons are ineffective over the Pb 6<i>p</i> shell. Most importantly, our parameter-free approach, finds a <i>T</i><sup>-3/2</sup> power-law temperature dependence of the mobility, which is a strong indication of polaronic transport. Our work then offers an independent theoretical validation of the many hypotheses about the polaronic nature of the charge carriers in lead halide perovskites.