Abstract
As a novel semiconductor, hybrid halide perovskites become candidate materials for the next generation of solar cells due to their high conversion efficiency and low processing cost. In the face of the uncertainty of electric transport properties in experimental measurement, it is necessary to predict the upper limit of mobility that they theoretically achieve. In this work, a new approach is adopted to improve the computational efficiency. Phonon-limited mobility for CH3NH3SnX3 and CH3NH3PbX3 (X=Br and I) is successfully predicted by ab initio Boltzmann transport equation (BTE) including all electron–phonon interactions (EPI). The convergent values for high frequency dielectric constant and Born effective charge are first obtained with moderate k grids of 16×16×16, and then they are substituted into the program. Subsequently, EPI matrix element is obtained by density functional perturbation theory (DFPT) with coarse 4×4×4k/q grids. To correct the shape of the band edge, the spin–orbit coupling (SOC) effect is included in the calculation. We reveal that longitudinal optical (LO) phonons associated with the stretching of Pb(Sn)-I(Br) atoms limit carrier mobility. CH3NH3SnI3 exhibits higher mobility than other materials. Its drift mobility is as high as μe=403∼559 and μh=1558∼1734cm2V−1s−1. Furthermore, Hall factor is investigated by analyzing the average relaxation time, and Hall mobility is predicted to be μe=432∼598 and μh=1725∼1920cm2V−1s−1. Compared with other typical semiconductors, CH3NH3SnI3 exhibits high hole mobility.
Published Version
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