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Jari Järvi, Jingrui Li and Patrick Rinke have developed a multiscale model to describe the disordered structures in hybrid perovskites. This model can generate large-scale picture of these amazing materials in good agreement with reality, and allows real-time dynamical simulation of important processes such as charge transport.

Multi-scale model for the structure of hybrid perovskites: analysis of charge migration in disordered MAPbI3 structures

Jari Järvi, Jingrui Li and Patrick Rinke, New J. Phys., 20 103013 (2018) ()

We have developed a multi-scale model for organic-inorganic hybrid perovskites (HPs) that applies quantum mechanical (QM) calculations of small HP supercell models to large coarse-grained structures. With a mixed quantum-classical hopping model, we have studied the effects of cation disorder on charge mobilities in HPs, which is a key feature to optimize their photovoltaic performance. Our multi-scale model parametrizes the interaction between neighbouring methylammonium cations (MA+) in the prototypical HP material, methylammonium lead triiodide (CH3NH3PbI3, or MAPbI3). For the charge mobility analysis with our hopping model, we solved the QM site-to-site hopping probabilities analytically and computed the nearest-neighbor electronic coupling energies from the band structure of MAPbI3 with density-functional theory. We investigated the charge mobility in various MAPbI3 supercell models of ordered and disordered MA+ cations. Our results indicate a structure-dependent mobility, in the range of 50–66 cm2V-1s-1, with the highest observed in the ordered tetragonal phase.