Understanding the role of Cesium and Rubidium additives in perovskite solar cells: trap states, charge transport, and recombination

Hu, Y. et al. (2018) Understanding the role of Cesium and Rubidium additives in perovskite solar cells: trap states, charge transport, and recombination. Advanced Energy Materials, 8(16), 1703057. (doi: 10.1002/aenm.201703057)

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Adding cesium (Cs) and rubidium (Rb) cations to FA0.83MA0.17Pb(I0.83Br0.17)3 hybrid lead halide perovskites results in a remarkable improvement in solar cell performance, but the origin of the enhancement has not been fully understood yet. In this work, time‐of‐flight, time‐resolved microwave conductivity, and thermally stimulated current measurements are performed to elucidate the impact of the inorganic cation additives on the trap landscape and charge transport properties within perovskite solar cells. These complementary techniques allow for the assessment of both local features within the perovskite crystals and macroscopic properties of films and full devices. Strikingly, Cs‐incorporation is shown to reduce the trap density and charge recombination rates in the perovskite layer. This is consistent with the significant improvements in the open‐circuit voltage and fill factor of Cs‐containing devices. By comparison, Rb‐addition results in an increased charge carrier mobility, which is accompanied by a minor increase in device efficiency and reduced current–voltage hysteresis. By mixing Cs and Rb in quadruple cation (Cs‐Rb‐FA‐MA) perovskites, the advantages of both inorganic cations can be combined. This study provides valuable insights into the role of these additives in multiple‐cation perovskite solar cells, which are essential for the design of high‐performance devices.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Docampo, Dr Pablo
Authors: Hu, Y., Hutter, E. M., Rieder, P., Grill, I., Hanisch, J., Aygüler, M. F., Hufnagel, A. G., Handloser, M., Bein, T., Hartschuh, A., Tvingstedt, K., Dyakonov, V., Baumann, A., Savenije, T. J., Petrus, M. L., and Docampo, P.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Advanced Energy Materials
ISSN (Online):1614-6840
Published Online:26 January 2018
Copyright Holders:Copyright © 2018 WILEY-VCH Verlag GmbH and Co. KGaA,
First Published:First published in Advanced Energy Materials 8(16):1703057
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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