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Molecular ferroelectric contributions to anomalous hysteresis in hybrid perovskite solar cells

Research paper by Jarvist M. Frost, Keith T. Butler, Aron Walsh

Indexed on: 19 Jun '14Published on: 19 Jun '14Published in: Physics - Mesoscopic Systems and Quantum Hall Effect



Abstract

We report a model describing the molecular orientation disorder in CH3NH3PbI3, solving a classical Hamiltonian parametrised with electronic structure calculations, with the nature of the motions informed by ab-initio molecular dynamics. We investigate the temperature and static electric field dependence of the equilibrium ferroelectric (molecular) domain structure and resulting polarisability. A rich domain structure of twinned molecular dipoles is observed, strongly varying as a function of temperature and applied electric field. We propose that the internal electrical fields associated with microscopic polarisation domains contribute to hysteretic anomalies in the current--voltage response of hybrid organic-inorganic perovskite solar cells due to variations in electron-hole recombination in the bulk.