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dc.contributor.authorThampi, Aryaen
dc.contributor.authorStern, Hannahen
dc.contributor.authorCheminal, Alexandreen
dc.contributor.authorPetty II, Johnen
dc.contributor.authorAnthony, Johnen
dc.contributor.authorRao, Akshayen
dc.date.accessioned2018-03-01T11:18:57Z
dc.date.accessioned2018-05-03T19:20:56Z
dc.date.available2018-03-01T11:18:57Z
dc.date.available2018-05-03T19:20:56Z
dc.identifier.issn0002-7863
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/275547
dc.description.abstractSinglet fission is the spin allowed conversion of a photo-generated singlet exciton into two triplet excitons in organic semiconductors, which could enable single-junction photovoltaic cells to break the Shockley-Queisser limit. The conversion of singlets to free triplets is mediated by an intermediate correlated triplet pair (TT) state, but an understanding of how the formation and dissociation of these states depend on energetics and morphology is lacking. In this study, we probe the dynamics of TT states in a model endothermic fission system, TIPS-Tc nanoparticles, which show a mixture of crystalline and disordered regions. We observe the formation of different TT states, with varying yield and different rates of singlet decay, depending on the excitation energy. An emissive TT state is observed to grow in over 1ns when exciting at 480nm, in contrast to excitation at lower energies where this emissive TT state is not observed. This suggests that the pathway for singlet fission in these nanoparticles is strongly influenced by the initial sub-100 fs relaxation of the photoexcited state away from the Frank-Condon point, with multiple possible TT states. On nanosecond timescales, the TT states are converted to free triplets, which suggests that TT states might diffuse into the disordered regions of the nanoparticles where their breakup to free triplets is favored. The free triplets then decay on µs timescales, despite the confined nature of the system. Our results provide important insights into the mechanism of endothermic singlet fission and the design of nanostructures to harness singlet fission.
dc.description.sponsorshipWe acknowledge EPSRC and the Winton Programme for the Physics of Sustainability for funding. A.T. thanks the Dr. Manmohan Singh scholarship, St John’s College, University of Cambridge, for funding. M.J.Y.T. acknowledges receipt of a Marie Curie Individual Fellowship.
dc.publisherAmerican Chemical Society
dc.relation.replaceshttps://www.repository.cam.ac.uk/handle/1810/273650
dc.relation.replaces1810/273650
dc.titleElucidation of Excitation Energy Dependent Correlated Triplet Pair Formation Pathways in an Endothermic Singlet Fission Systemen
dc.typeArticle
prism.endingPage4622
prism.issueIdentifier13en
prism.publicationNameJournal of the American Chemical Societyen
prism.startingPage4613
prism.volume140en
dc.identifier.doi10.17863/CAM.20708
dc.identifier.doi10.17863/CAM.22785
dcterms.dateAccepted2017-12-24en
rioxxterms.versionofrecord10.1021/jacs.7b06274en
rioxxterms.versionAM*
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2017-12-24en
dc.contributor.orcidThampi, Arya [0000-0001-6003-5991]
dc.contributor.orcidCheminal, Alexandre [0000-0001-9969-672X]
dc.contributor.orcidRao, Akshay [0000-0003-0320-2962]
dc.identifier.eissn1520-5126
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEPSRC (EP/M006360/1)
pubs.funder-project-idEPSRC (EP/M024873/1)
pubs.funder-project-idEPSRC (EP/P027741/1)
pubs.funder-project-idEuropean Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (705113)
cam.issuedOnline2017-12-24en
rioxxterms.freetoread.startdate2018-12-24


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