Tetrafluoroborate-Induced Reduction in Defect Density in Hybrid Perovskites through Halide Management
Authors
Hope, mic
Li, weiwei
Verma, S
Chiang, Y
Publication Date
2021-08Journal Title
Advanced Materials
ISSN
0935-9648
Publisher
Wiley
Volume
33
Issue
32
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Nagane, S., Hope, m., Kubicki, D., Li, w., Verma, S., Ferrer Orri, J., Chiang, Y., et al. (2021). Tetrafluoroborate-Induced Reduction in Defect Density in Hybrid Perovskites through Halide Management. Advanced Materials, 33 (32) https://doi.org/10.1002/adma.202102462
Abstract
Hybrid perovskite-based optoelectronic devices are demonstrating unprecedented growth in
performance, and defect passivation approaches are highly promising routes to further improve
properties. Here, the effect of the molecular ion BF4-, introduced via methylammonium
tetrafluoroborate (MABF4) in a surface treatment for MAPbI3 perovskite is reported. The
optical spectroscopic characterisations shows that the introduction of tetrafluoroborate leads to
reduced non-radiative charge carrier recombination with a reduction in first order
recombination rate from 6.5 × 106 to 2.5 × 105 s-1 in BF4--treated samples, and a consequent
increase in photoluminescence quantum yield by an order of magnitude (from 0.5% to 10.4%).
19F, 11B and 14N solid-state NMR is used to elucidate the atomic-level mechanism of the BF4- additive-induced improvements, revealing that the BF4- acts as a scavenger of excess MAI by
forming MAI–MABF4 cocrystals. This shifts the equilibrium of iodide concentration in the
perovskite phase is presumably due to the formation of MAI-MABF4 cocrystal, thereby
reducing the concentration of interstitial iodide defects that act as deep traps and non-radiative
recombination centers. These collective results allow us, for the first time, to elucidate the
microscopic mechanism of action of BF4-.
Relationships
Is supplemented by: https://doi.org/10.17863/CAM.70304
Sponsorship
S.N. would like to acknowledge Royal Society-SERB Newton International Fellowship for
funding. S.D.S. acknowledges the Royal Society and Tata Group (UF150033) and the EPSRC
(EP/R023980/1). This work has received funding from the European Union’s Horizon 2020
research and innovation program under the Marie Skłodowska-Curie grant agreement No.
841136. M.A.H. acknowledges support from the Royal Society (RP/R1/180147). S.M. thanks
the EPRSC for funding. J.L.M-D. and W.-W. L. thank the UK Royal Academy of Engineering,
grant CiET1819_24, EPSRC grants EP/N004272/1, EP/P007767/1, the Winton Programme for
the Physics of Sustainability, and Bill Welland.
Funder references
Royal Society (UF150033)
European Research Council (756962)
Engineering and Physical Sciences Research Council (EP/R023980/1)
Royal Society (NIF\R1\181365)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (841136)
Engineering and Physical Sciences Research Council (EP/N004272/1)
Engineering and Physical Sciences Research Council (EP/P007767/1)
Embargo Lift Date
2100-01-01
Identifiers
External DOI: https://doi.org/10.1002/adma.202102462
This record's URL: https://www.repository.cam.ac.uk/handle/1810/322436
Rights
Attribution 4.0 International (CC BY)
Licence URL: http://creativecommons.org/licenses/by/4.0/
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