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HL: Fachverband Halbleiterphysik

HL 21: Photo-voltaics II

HL 21.1: Vortrag

Dienstag, 13. März 2018, 14:00–14:15, EW 202

First principles carrier lifetimes, effective masses, and mobilities in MAPbI₃ — •Martin Schlipf, Samuel Ponce, and Feliciano Giustino — Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom

Electron-phonon coupling (EPC) fundamentally limits the mobility of charge carriers in halide perovskites. A comprehensive study of all EPC effects has not been conducted fully from ab initio, because the organic molecule leads to a large number of atoms in the primitive unit cell. We performed a detailed analysis of the prototypical methylammonium (MA) lead iodide (MAPbI₃) in its orthorhombic ground state structure. This contribution assesses the relative impact various scattering channels on the lifetime, mass renormalization, and carrier mobility. A breathing mode of the octahedra emerges as the dominant scattering channel, but two further polar phonon modes exhibit a significant contribution to lifetime and mass renormalization. The coupling to acoustical and transversal phonon modes is weak. The relaxation time of carriers due to this scattering mechanism is below 10 fs at room temperature. The calculated mobilities of the electron and the hole are very similar due to their comparable effective masses and agrees with experimental observations over a wide temperature range. We expect the possibility of higher mobility devices by selective engineering of the identified relevant scattering processes.