Quantifying Polaronic Effects on Charge-Carrier Scattering and Mobility in Organometal Halide Perovskites

The formation of large polarons due to the interaction between charge carriers and the crystal lattice has been proposed to have wide-ranging effects on charge carrier dynamics in organometal halide perovskites (OHPs), with an underlying hypothesis that charge carriers are “protected” from scattering [1, 2]. We derive expressions for the rates of scattering of polarons by polar optical phonons, acoustic phonons and ionised impurities, and quantify them for electrons and holes in the OHPs MAPbI₃, MAPbBr₃ and CsPbI₃. We then compute polaron momentum distribution functions which satisfy the Boltzmann transport equation using a semiclassical Monte Carlo method, from which we extract temperature dependent mobilities. By carrying out analogous calculations for bare band carriers, we conclude that polaronic effects on the scattering and mobilities of charge carriers in OHPs are limited, contrary to claims in the recent literature.

[1] Zhu, X. and Podzorov, V. J. Phys. Chem. Lett. 6, 4758 (2015)
[2] Ghosh, D. et al. J. Phys. Chem. Lett. 11, 9, 3271 (2020)