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Interface limited hole extraction from methylammonium lead iodide films
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dc.contributor.author | Blaszczyk, Oskar | |
dc.contributor.author | Krishnan Jagadamma, Lethy | |
dc.contributor.author | Ruseckas, Arvydas | |
dc.contributor.author | Sajjad, Muhammad Tariq | |
dc.contributor.author | Zhang, Yiwei | |
dc.contributor.author | Samuel, Ifor David William | |
dc.date.accessioned | 2020-01-06T17:30:02Z | |
dc.date.available | 2020-01-06T17:30:02Z | |
dc.date.issued | 2019-12-09 | |
dc.identifier | 263751537 | |
dc.identifier | cf11c9d5-c589-47c3-b650-22b7c9afc442 | |
dc.identifier | 85082240957 | |
dc.identifier | 000519943400021 | |
dc.identifier.citation | Blaszczyk , O , Krishnan Jagadamma , L , Ruseckas , A , Sajjad , M T , Zhang , Y & Samuel , I D W 2019 , ' Interface limited hole extraction from methylammonium lead iodide films ' , Materials Horizons , vol. Advance Article . https://doi.org/10.1039/C9MH01517E | en |
dc.identifier.issn | 2051-6347 | |
dc.identifier.other | ORCID: /0000-0001-9114-3522/work/66398372 | |
dc.identifier.other | ORCID: /0000-0002-4339-2484/work/66398428 | |
dc.identifier.uri | https://hdl.handle.net/10023/19231 | |
dc.description | This work was supported by the Engineering and Physical Sciences Research Council (grant EP/L017008/1 and studentship grant EP/M508214/1 to O. Blaszczyk) and the European Research Council (grant 321305). Dr L. K. Jagadamma acknowledges support from a Marie Skłodowska-Curie Individual Fellowship (European Commission) (MCIF: No. 745776). | en |
dc.description.abstract | Small solar cells based on metal halide perovskites have shown a tremendous increase in efficiency in recent years. These huge strides in device performance make it important to understand processes such as accumulation and extraction of charge carriers to better address the scalability and stability challenges which have not been solved yet. In most studies to date it is unclear whether the limiting factor of charge extraction is charge transport in the bulk of the perovskite or transfer across the interface with the charge extracting layer, owing largely to the inaccessibility of buried interfaces. Separating bulk and interfacial effects on charge extraction can help the search for new charge extracting materials, improve understanding of charge transport in active layer materials and help optimise device performance; not only in the laboratory setting but also for commercial production. Here we present a method to unambiguously distinguish between bulk and interface effects on charge extraction dynamics which is based on time-resolved photoluminescence with different excitation density profiles. We use this method to study charge extraction from solution-deposited CH3NH3PbI3 films to NiO and PEDOT:PSS layers. We find that NiO shows faster hole extraction than PEDOT:PSS from the 300 nm thick perovskite film on the time scale of 300 ps which is independent of charge carrier density in the region of 1016-1017 cm-3 . The interface with NiO is found to only slightly limit charge extraction rate at charge densities exceeding 1016 cm-3 as the extraction rate is fast and does not decrease with time. This is in contrast to PEDOT:PSS where we find the charge extraction rate to be slower, decreasing with time and dependent on charge density in the region 1016-1017 cm-3 which we interpret as charge accumulation at the interface. Hence we find that charge extraction is severely limited by the interface with PEDOT:PSS. These findings are confirmed by transient absorption spectroscopy. A hole diffusion coefficient of D=(2.2 ±0.4) cm2/s was determined in the perovskite film that is independent of charge density. This indicates a band-like hole transport regime, not observed for solution processed films before. Our findings stress the importance of interface optimization in devices based on perovskite active layers as there is still room for improvement of the hole extraction rate even in the case of the superior NiO layer. | |
dc.format.extent | 2380252 | |
dc.language.iso | eng | |
dc.relation.ispartof | Materials Horizons | en |
dc.subject | QC Physics | en |
dc.subject | TK Electrical engineering. Electronics Nuclear engineering | en |
dc.subject | DAS | en |
dc.subject.lcc | QC | en |
dc.subject.lcc | TK | en |
dc.title | Interface limited hole extraction from methylammonium lead iodide films | en |
dc.type | Journal article | en |
dc.contributor.sponsor | EPSRC | en |
dc.contributor.institution | University of St Andrews. School of Physics and Astronomy | en |
dc.contributor.institution | University of St Andrews. Centre for Biophotonics | en |
dc.contributor.institution | University of St Andrews. Condensed Matter Physics | en |
dc.identifier.doi | https://doi.org/10.1039/C9MH01517E | |
dc.description.status | Peer reviewed | en |
dc.date.embargoedUntil | 2019-12-09 | |
dc.identifier.grantnumber | ep/l017008/1 | en |
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