Rothmann, Mathias Uller, Lohmann, Kilian B., Borchert, Juliane et al. (4 more authors) (2023) Atomistic Understanding of the Coherent Interface Between Lead Iodide Perovskite and Lead Iodide. Advanced materials interfaces. ISSN 2196-7350
Abstract
Abstract Metal halide perovskite semiconductors have shown great performance in solar cells, and including an excess of lead iodide (PbI2) in the thin films, either as mesoscopic particles or embedded domains, often leads to improved solar cell performance. Atomic resolution scanning transmission electron microscope micrographs of formamidinium lead iodide (FAPbI3) perovskite films reveal the FAPbI3:PbI2 interface to be remarkably coherent. It is demonstrated that such interface coherence is achieved by the PbI2 deviating from its common 2H hexagonal phase to form a trigonal 3R polytype through minor shifts in the stacking of the weakly van-der-Waals-bonded layers containing the near-octahedral units. The exact crystallographic interfacial relationship and lattice misfit are revealed. It is further shown that this 3R polytype of PbI2 has similar X-ray diffraction (XRD) peaks to that of the perovskite, making XRD-based quantification of the presence of PbI2 unreliable. Density functional theory demonstrates that this interface does not introduce additional electronic states in the bandgap, making it electronically benign. These findings explain why a slight PbI2 excess during perovskite film growth can help template perovskite crystal growth and passivate interfacial defects, improving solar cell performance.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Authors. |
Keywords: | electron microscopy,electronic structure of crystallographic interfaces,lead iodide polytypes,perovskite solar cells |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Physics (York) |
Funding Information: | Funder Grant number EPSRC EP/P023843/1 |
Depositing User: | Pure (York) |
Date Deposited: | 26 Jul 2023 10:00 |
Last Modified: | 08 Feb 2025 00:50 |
Published Version: | https://doi.org/10.1002/admi.202300249 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1002/admi.202300249 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:201908 |
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Description: Adv Materials Inter - 2023 - Rothmann - Atomistic Understanding of the Coherent Interface Between Lead Iodide Perovskite
Licence: CC-BY 2.5