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dc.contributor.authorClassen, Andrej
dc.contributor.authorChochos, Christos L.
dc.contributor.authorLüer, Larry
dc.contributor.authorGregoriou, Vasilis G.
dc.contributor.authorWortmann, Jonas
dc.contributor.authorOsvet, Andres
dc.contributor.authorForberich, Karen
dc.contributor.authorMcCulloch, Iain
dc.contributor.authorHeumüller, Thomas
dc.contributor.authorBrabec, Christoph J.
dc.date.accessioned2020-09-07T12:16:50Z
dc.date.available2020-09-07T12:16:50Z
dc.date.issued2020-08-31
dc.date.submitted2019-10-18
dc.identifier.citationClassen, A., Chochos, C. L., Lüer, L., Gregoriou, V. G., Wortmann, J., Osvet, A., … Brabec, C. J. (2020). The role of exciton lifetime for charge generation in organic solar cells at negligible energy-level offsets. Nature Energy. doi:10.1038/s41560-020-00684-7
dc.identifier.issn2058-7546
dc.identifier.doi10.1038/s41560-020-00684-7
dc.identifier.urihttp://hdl.handle.net/10754/664985
dc.description.abstractOrganic solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate organic solar cell blends with highest occupied molecular orbital energy-level offsets (∆EHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ∆EHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quantitatively describe this finding via the Boltzmann stationary-state equilibrium between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ∆EHOMO. Moreover, the Boltzmann equilibrium quantitatively describes the major reduction in non-radiative voltage losses at a very small ∆EHOMO. Ultimately, highly luminescent near-infrared emitters with very long exciton lifetimes are suggested to enable highly efficient organic solar cells.
dc.description.sponsorshipA.C. and C.J.B. gratefully acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project no. 182849149-SFB 953. C.J.B. gratefully acknowledges financial support through the ‘Aufbruch Bayern’ initiative of the state of Bavaria (EnCN and SFF) and the Bavarian Initiative ‘Solar Technologies go Hybrid’ (SolTech) and funding from DFG project DFG INST 90/917. C.C.L. thanks the European Union for the financial support. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements no. 761112 (PRESTIGE) and no. 820789 (OLEDSOLAR).
dc.publisherSpringer Nature
dc.relation.urlhttp://www.nature.com/articles/s41560-020-00684-7
dc.rightsArchived with thanks to Nature Energy
dc.titleThe role of exciton lifetime for charge generation in organic solar cells at negligible energy-level offsets
dc.typeArticle
dc.contributor.departmentChemical Science Program
dc.contributor.departmentKAUST Solar Center (KSC)
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalNature Energy
dc.rights.embargodate2021-03-03
dc.eprint.versionPost-print
dc.contributor.institutionInstitute of Materials for Electronics and Energy Technology (i-MEET), Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
dc.contributor.institutionAdvent Technologies SA, Platani, Greece
dc.contributor.institutionInstitute of Chemical Biology, National Hellenic Research Foundation (NHRF), Athens, Greece
dc.contributor.institutionNational Hellenic Research Foundation (NHRF), Athens, Greece
dc.contributor.institutionDepartment of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
dc.contributor.institutionHelmholtz-Institute Erlangen-Nürnberg (HI ERN), Erlangen, Germany
dc.contributor.institutionBavarian Center for Applied Energy Research (ZAE Bayern), Erlangen, Germany
kaust.personMcCulloch, Iain
dc.date.accepted2020-07-29
dc.identifier.eid2-s2.0-85089969136
dc.date.published-online2020-08-31
dc.date.published-print2020-09


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