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dc.contributor.authorPandya, Rajen
dc.date.accessioned2020-10-14T23:31:52Z
dc.date.available2020-10-14T23:31:52Z
dc.identifier.issn1936-0851
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/311539
dc.description.abstractLuminescent colloidal CdSe nanorings are a new type of semiconductor structure that have attracted interest due to the potential for unique physics arising from their non-trivial toroidal shape. However, the exciton properties and dynamics of these materials with complex topology are not yet well understood. Here, we use a combination of femtosecond vibrational spectroscopy, temperature-resolved photoluminescence (PL), and single particle measurements to study these materials. We find that on transformation of CdSe nanoplatelets to nanorings, by perforating the center of platelets, the emission lifetime decreases and the emission spectrum broadens due to ensemble variations in the ring size and thickness. The reduced PL quantum yield of nanorings (~10%) compared to platelets (~30%) is attributed to an enhanced coupling between: (i) excitons and CdSe LO-phonons at 200 cm-1 and (ii) negatively charged selenium-rich traps which give nanorings a high surface charge (~-50 mV). Population of these weakly emissive trap sites dominates the emission properties with an increased trap emission at low temperatures relative to excitonic emission. Our results provide a detailed picture of the nature of excitons in nanorings and the influence of phonons and surface charge in explaining the broad shape of the PL spectrum and the origin of PL quantum yield losses. Furthermore, they suggest that the excitonic properties of nanorings are not solely a consequence of the toroidal shape but are also a result of traps introduced by puncturing the platelet center.
dc.publisherAmerican Chemical Society
dc.rightsAll rights reserved
dc.titleOptical and electronic properties of colloidal CdSe Quantum Ringsen
dc.typeArticle
prism.publicationNameACS Nanoen
dc.identifier.doi10.17863/CAM.58632
dcterms.dateAccepted2020-10-06en
rioxxterms.versionofrecord10.1021/acsnano.0c01752en
rioxxterms.versionAM
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2020-10-06en
dc.contributor.orcidPandya, Raj [0000-0003-1108-9322]
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idEPSRC (1805376)
cam.issuedOnline2020-10-13en
datacite.issupplementedby.urlhttps://doi.org/10.17863/CAM.58042
cam.orpheus.successMon Oct 19 07:30:25 BST 2020 - Embargo updated*
rioxxterms.freetoread.startdate2021-10-13


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