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Liu, Sue ; Borys, Nicholas J. ; Huang, Jing ; Talapin, Dmitri V. ; Lupton, John M.

Exciton storage in CdSe/CdS tetrapod semiconductor nanocrystals: Electric field effects on exciton and multiexciton states

Article

Liu, Sue, Borys, Nicholas J., Huang, Jing, Talapin, Dmitri V. and Lupton, John M. (2012) Exciton storage in CdSe/CdS tetrapod semiconductor nanocrystals: Electric field effects on exciton and multiexciton states. Physical Review B (PRB) 86 (4), 045303.

DOI to cite this document: 10.5283/epub.26694


Abstract

CdSe/CdS nanocrystal tetrapods are interesting building blocks for excitonic circuits, where the flow of excitation energy is gated by an external stimulus. The physical morphology of the nanoparticle, along with the electronic structure, which favors electron delocalization between the two semiconductors, suggests that all orientations of a particle relative to an external electric field will ...

CdSe/CdS nanocrystal tetrapods are interesting building blocks for excitonic circuits, where the flow of excitation energy is gated by an external stimulus. The physical morphology of the nanoparticle, along with the electronic structure, which favors electron delocalization between the two semiconductors, suggests that all orientations of a particle relative to an external electric field will allow for excitons to be dissociated, stored, and released at a later time. While this approach, in principle, works, and fluorescence quenching of over 95% can be achieved electrically, we find that discrete trap states within the CdS are required to dissociate and store the exciton. These states are rapidly filled up with increasing excitation density, leading to a dramatic reduction in quenching efficiency. Charge separation is not instantaneous on the CdS excitonic antennae in which light absorption occurs, but arises from the relaxed exciton following hole localization in the core. Consequently, whereas strong electromodulation of the core exciton is observed, the core multiexciton and the CdS arm exciton are not affected by an external electric field.



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Details

Item typeArticle
Journal or Publication TitlePhysical Review B (PRB)
PublisherAMER PHYSICAL SOC
Open Access TypeDue to SHERPA/RoMEO
Place of PublicationCOLLEGE PK
Volume86
Number of Issue or Book Chapter4
Page Range045303
Date9 July 2012
Date of publication15 Nov 2012 08:20
InstitutionsPhysics > Institute of Experimental and Applied Physics > Chair Professor Lupton > Group John Lupton
Identification Number
ValueType
10.1103/PhysRevB.86.045303DOI
Classification
NotationType
73.22.-fPACS
73.50.GrPACS
73.63.BdPACS
78.47.D-PACS
KeywordsQUANTUM DOTS; PHOTOLUMINESCENCE INTENSITY; DYNAMICS; RECOMBINATION; EMISSION; FLUORESCENCE; CHARGE; AUGER; WELL; SPIN;
Dewey Decimal Classification500 Science > 530 Physics
StatusPublished
RefereedYes, this version has been refereed
Created at the University of RegensburgPartially
URN of the UB Regensburgurn:nbn:de:bvb:355-epub-266945
Item ID26694

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