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dc.contributor.authorJakowetz, Andreasen
dc.contributor.authorBöhm, MLen
dc.contributor.authorSadhanala, Adityaen
dc.contributor.authorHuettner, Sen
dc.contributor.authorRao, Aen
dc.contributor.authorFriend, Richarden
dc.date.accessioned2017-03-31T16:24:50Z
dc.date.available2017-03-31T16:24:50Z
dc.identifier.issn1476-1122
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/263429
dc.description.abstractInterfaces play a crucial role in semiconductor devices, but in many device architectures they are nanostructured, disordered and buried away from the surface of the sample. Conventional optical, X-ray and photoelectron probes often fail to provide interface-specific information in such systems. Here we develop an all-optical time-resolved method to probe the local energetic landscape and electronic dynamics at such interfaces, based on the Stark effect caused by electron–hole pairs photo-generated across the interface. Using this method, we found that the electronically active sites at the polymer/fullerene interfaces in model bulk-heterojunction blends fall within the low-energy tail of the absorption spectrum. This suggests that these sites are highly ordered compared with the bulk of the polymer film, leading to large wavefunction delocalization and low site energies. We also detected a 100 fs migration of holes from higher- to lower-energy sites, consistent with these charges moving ballistically into more ordered polymer regions. This ultrafast charge motion may be key to separating electron–hole pairs into free charges against the Coulomb interaction.
dc.description.sponsorshipThis work was supported by the Engineering and Physical Sciences Research Council (EPSRC) and the Winton Programme for the Physics of Sustainability. A.C.J. thanks the University of Cambridge for funding (CHESS). Synchrotron measurements were undertaken on the SAXS beamline at the Australian Synchrotron, Victoria, Australia and we acknowledge the help of N. Lal with the measurements. S.H. thanks the framework project Soltech for funding.
dc.languageengen
dc.language.isoenen
dc.publisherNature Publishing Group
dc.subjectelectron transferen
dc.subjectexcited statesen
dc.subjectsolar cellsen
dc.subjectoptical spectroscopyen
dc.titleVisualizing excitations at buried heterojunctions in organic semiconductor blendsen
dc.typeArticle
prism.publicationNameNature Materialsen
dc.identifier.doi10.17863/CAM.8771
dcterms.dateAccepted2017-01-19en
rioxxterms.versionofrecord10.1038/nmat4865en
rioxxterms.versionAMen
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2017-01-19en
dc.contributor.orcidSadhanala, Aditya [0000-0003-2832-4894]
dc.contributor.orcidFriend, Richard [0000-0001-6565-6308]
dc.identifier.eissn1476-4660
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEPSRC (1227777)
pubs.funder-project-idEngineering and Physical Sciences Research Council (EP/M006360/1)
cam.issuedOnline2017-02-20en
rioxxterms.freetoread.startdate2017-08-20


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