Light-induced reversal of ion segregation in mixed-halide perovskites
Wenxin Mao, Christopher R Hall, Stefano Bernardi, Yi-Bing Cheng, Asaph Widmer-Cooper, Trevor A Smith, Udo Bach
NATURE MATERIALS | NATURE RESEARCH | Published : 2021
Bandgap instability due to light-induced phase segregation in mixed-halide perovskites presents a major challenge for their future commercial use. Here we demonstrate that photoinduced halide-ion segregation can be completely reversed at sufficiently high illumination intensities, enabling control of the optical bandgap of a mixed-halide perovskite single crystal by optimizing the input photogenerated carrier density. We develop a polaron-based two-dimensional lattice model that rationalizes the experimentally observed phenomena by assuming that the driving force for photoinduced halide segregation is dependent on carrier-induced strain gradients that vanish at high carrier densities. Using ..View full abstract
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Awarded by Australian Research Council through the Centre of Excellence in Exciton Science
Awarded by Australian Research Council
This work was financially supported by the Australian Research Council through the Centre of Excellence in Exciton Science (CE170100026) and additional grants (DP160104575, LE170100235). We acknowledge financial support from the Australian Government through the Australian Renewable Energy Agency and the Australian Centre for Advanced Photovoltaics (ACAP). W.M. acknowledges an ACAP fellowship supported by the Australian Government through the Australian Renewable Energy Agency (ARENA). We acknowledge XPS measurements by T. Gengenbach from The Commonwealth Scientific and Industrial Research Organisation (CSIRO). We also acknowledge the use of facilities within the Monash Centre for Electron Microscopy (MCEM), Monash X-Ray Platform and Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). This work was supported by resources provided by the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia.