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Dramatic maturing effects on all inorganic CsPbBr3 perovskite solar cells under different storage conditions

Commandeur, Daniel; Draper, Thomas; Alabdulla, Zainab T. Y.; Qian, Rong; Chen, Qiao

Authors

Daniel Commandeur

Dr Thomas Draper Tom.Draper@uwe.ac.uk
Research Fellow Biosensing/ Healthcare Technology

Zainab T. Y. Alabdulla

Rong Qian

Qiao Chen



Abstract

As perovskite solar cells have yielded impressive efficiency at a low cost, the focus has shifted to increase their service life as they are plagued by rapid degradation. Refreshingly, CsPbBr3 solar cells built on a conductive ZnO nanowire electron transport layer with a graphite counter electrode not only avoided degradation but also showed some of the reverse trends under specific conditions, showing significant maturation over time. In this work, this phenomenon is first confirmed to be reproducible from a large sample size with on average a 40 ± 10% increase in efficiency after 2 weeks of storage. To explore the mechanisms of this positive maturing effect, samples were stored under different controlled conditions and tested regularly by using scanning electron microscopy, powder X-ray diffraction, current-voltage (IV) curves, and impedance spectroscopy. The samples stored in a methanol atmosphere presented a dramatic positive effect, giving a 4-fold increase in efficiency after 2 days of storage. However, in the saturated H2O environment, the device performance rapidly degraded. By observing the solar cell performance affected by various storage conditions, including various solvent vapors, light illumination, and an inert gas (N2), we suggest three possible complementary factors. First, solvents shifted the equilibrium of crystal phase ratio of CsPbBr3 to CsPb2Br5. Second, the CsPbBr3 grain size was reduced with improved electrical contact with the conductive ZnO nanowires. Finally, ion migration and accumulation lead to the formation of local p-n junctions at crystal grain boundaries with improved charge separation. This was evidenced by the increased kinetic relaxation times on ionic time scales. Rather than degrading, under appropriate conditions, these cells were able to increase in value/efficiency over storage time. By elucidating the underlying mechanisms for the CsPbBr3 solar cell stability, the work offers guidelines for improving perovskite solar cell long-term efficiency.

Citation

Commandeur, D., Draper, T., Alabdulla, Z. T. Y., Qian, R., & Chen, Q. (2021). Dramatic maturing effects on all inorganic CsPbBr3 perovskite solar cells under different storage conditions. Journal of Physical Chemistry C, 125(36), 19642-19652. https://doi.org/10.1021/acs.jpcc.1c05714

Journal Article Type Article
Acceptance Date Aug 20, 2021
Online Publication Date Sep 2, 2021
Publication Date Sep 16, 2021
Deposit Date Apr 7, 2022
Publicly Available Date Mar 28, 2024
Journal Journal of Physical Chemistry C
Print ISSN 1932-7447
Electronic ISSN 1932-7455
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 125
Issue 36
Pages 19642-19652
DOI https://doi.org/10.1021/acs.jpcc.1c05714
Keywords Surfaces, Coatings and Films; Physical and Theoretical Chemistry; General Energy; Electronic, Optical and Magnetic Materials
Public URL https://uwe-repository.worktribe.com/output/9303887