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dc.contributor.authorZhang, Siyuan
dc.contributor.authorTang, Ming-Chun
dc.contributor.authorFan, Yuanyuan
dc.contributor.authorLi, Ruipeng
dc.contributor.authorNguyen, Nhan V
dc.contributor.authorZhao, Kui
dc.contributor.authorAnthopoulos, Thomas D.
dc.contributor.authorHacker, Christina A
dc.date.accessioned2020-07-22T10:41:04Z
dc.date.available2020-07-22T10:41:04Z
dc.date.issued2020-07-01
dc.date.submitted2020-05-07
dc.identifier.citationZhang, S., Tang, M.-C., Fan, Y., Li, R., Nguyen, N. V., Zhao, K., … Hacker, C. A. (2020). Role of Alkali-Metal Cations in Electronic Structure and Halide Segregation of Hybrid Perovskites. ACS Applied Materials & Interfaces. doi:10.1021/acsami.0c08396
dc.identifier.issn1944-8244
dc.identifier.pmid32609487
dc.identifier.doi10.1021/acsami.0c08396
dc.identifier.urihttp://hdl.handle.net/10754/664352
dc.description.abstractThe ability to control or prevent phase segregation in perovskites is crucial to realizing stable and tunable mixed-halide optoelectronic devices. In this work, we systematically examine the impact of alkali-metal-cation (Cs+ and K+) concentration on the band structure, chemical composition, phase segregation, and polycrystalline microstructure on formamidinium-dominated mixed-halide mixed-cation perovskite films. It was found that the incorporation of Cs+ and K+ cations decreases the work function and the core levels of all components shift toward higher binding energy consistent with n-doping the perovskite film, which facilitates electron transfer to the electron transport layer TiO2. A concentration-dependent film structure was observed by X-ray photoemission spectroscopy and grazing incidence wide-angle X-ray scattering where the halides and cations are distributed evenly across perovskite films at low metallic cation concentration (5%). A high metal-cation ratio (20%) leads to halide segregation within the perovskite film and the surface becomes bromide-poor, whereas the bromide and metal cations diffuse more deeply within the film. These differences in electronic properties, element distribution, and film morphology were reflected in the device performance where the power conversion efficiency of low-metallic-cation concentration (5% of Cs+ and K+) perovskite solar cells is ≈5% higher than the high-concentration ones (20%). This study provides valuable chemical and physical insight into the underlying trade-offs in the careful tuning of electrical properties and film structure to optimize multication and mixed-halide hybrid perovskites.
dc.description.sponsorshipThis work was supported by the National Institute of Standards and Technology (NIST) Financial Assistance Award with Federal Award ID 70NANB16H228, King Abdullah University of Science and Technology (KAUST), and National Natural Science Foundation of China (61974085). Dr. Tang acknowledges support under the Cooperative Research Agreement between the University of Maryland and the National Institute of Standards and Technology Physical Measurement Laboratory, Award 70NANB14H209, through the University of Maryland.
dc.publisherAmerican Chemical Society (ACS)
dc.relation.urlhttps://pubs.acs.org/doi/10.1021/acsami.0c08396
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS applied materials & interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsami.0c08396.
dc.titleRole of Alkali-Metal Cations in Electronic Structure and Halide Segregation of Hybrid Perovskites.
dc.typeArticle
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentMaterial Science and Engineering
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.contributor.departmentKAUST Solar Center (KSC)
dc.identifier.journalACS applied materials & interfaces
dc.rights.embargodate2021-07-02
dc.eprint.versionPost-print
dc.contributor.institutionPhysical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States
dc.contributor.institutionTheiss Research, La Jolla, California 92037, United States
dc.contributor.institutionInstitute for Research in Electronics and Applied Physics & Maryland NanoCenter, University of Maryland, College Park, Maryland 20742, United States
dc.contributor.institutionKey Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, and Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710119, China
dc.contributor.institutionBrookhaven National Laboratory (BNL), Upton, New York 11973, United States
kaust.personTang, Ming-Chun
kaust.personAnthopoulos, Thomas D.
dc.date.accepted2020-07-01
refterms.dateFOA2020-07-23T06:32:09Z
dc.date.published-online2020-07-01
dc.date.published-print2020-07-29


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