Local Nanoscale Phase Impurities are Degradation Sites in Halide Perovskites.
View / Open Files
Authors
Macpherson, Stuart
Winchester, Andrew J
Kosar, Sofiia
Johnstone, Duncan N
Galkowski, Krzystof
Andaji-Garmaroudi, Zahra
Parker, Julia E
Midgley, Paul A
Publication Date
2022-05-24Journal Title
Nature
ISSN
0028-0836
Publisher
Springer Science and Business Media LLC
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Macpherson, S., Doherty, T. A., Winchester, A. J., Kosar, S., Johnstone, D. N., Chiang, Y., Galkowski, K., et al. (2022). Local Nanoscale Phase Impurities are Degradation Sites in Halide Perovskites.. Nature https://doi.org/10.1038/s41586-022-04872-1
Abstract
Understanding the nanoscopic chemical and structural changes that drive instabilities in emerging energy materials is essential for mitigating device degradation. The power conversion efficiency of halide perovskite photovoltaic devices has reached 25.7% in single junction and 29.8% in tandem perovskite/silicon cells1,2, yet retaining such performance under continuous operation has remained elusive3. Here, we develop a multimodal microscopy toolkit to reveal that in leading formamidinium-rich perovskite absorbers, nanoscale phase impurities including hexagonal polytype and lead iodide inclusions are not only traps for photo-excited carriers which themselves reduce performance4,5, but via the same trapping process are sites at which photochemical degradation of the absorber layer is seeded. We visualise illumination-induced structural changes at phase impurities associated with trap clusters, revealing that even trace amounts of these phases, otherwise undetected with bulk measurements, compromise device longevity. The type and distribution of these unwanted phase inclusions depends on film composition and processing, with the presence of polytypes being most detrimental for film photo-stability. Importantly, we reveal that performance losses and intrinsic degradation processes can both be mitigated by modulating these defective phase impurities, and demonstrate that this requires careful tuning of local structural and chemical properties. This multimodal workflow to correlate the nanoscopic landscape of beam sensitive energy materials will be applicable to a wide range of semiconductors for which a local picture of performance and operational stability has yet to be established.
Sponsorship
Royal Society (UF150033)
European Research Council (756962)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (841136)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (841386)
Engineering and Physical Sciences Research Council (EP/S030638/1)
EPSRC (EP/T02030X/1)
EPSRC (2127077)
EPSRC (EP/V012932/1)
Engineering and Physical Sciences Research Council (EP/R023980/1)
Embargo Lift Date
2022-11-24
Identifiers
External DOI: https://doi.org/10.1038/s41586-022-04872-1
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337493
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.