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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2011-7-1
pubmed:abstractText
Improving the performance of photoactive solid-state devices begins with systematic studies of the metal-semiconductor nanocomposites (NCs) upon which such devices are based. Here, we report the photo-dependent excitonic mechanism and the charge migration kinetics in a colloidal ZnO-Au NC system. By using a picosecond-resolved Förster resonance energy transfer (FRET) technique, we have demonstrated that excited ZnO nanoparticles (NPs) resonantly transfer visible optical radiation to the Au NPs, and the quenching of defect-mediated visible emission depends solely on the excitation level of the semiconductor. The role of the gold layer in promoting photolytic charge transfer, the activity of which is dependent upon the degree of excitation, was probed using methylene blue (MB) reduction at the semiconductor interface. Incident photon-to-current efficiency measurements show improved charge injection from a sensitizing dye to a semiconductor electrode in the presence of gold in the visible region. Furthermore, the short-circuit current density and the energy conversion efficiency of the ZnO-Au NP based dye-sensitized solar cell (DSSC) are much higher than those of a DSSC comprised of only ZnO NP. Our results represent a new paradigm for understanding the mechanism of defect-state passivation and photolytic activity of the metal component in metal-semiconductor nanocomposite systems.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Jul
pubmed:issn
1463-9084
pubmed:author
pubmed:copyrightInfo
This journal is © the Owner Societies 2011
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12488-96
pubmed:year
2011
pubmed:articleTitle
Photoselective excited state dynamics in ZnO-Au nanocomposites and their implications in photocatalysis and dye-sensitized solar cells.
pubmed:affiliation
Department of Chemical, Biological and Macromolecular Sciences, Unit for Nano Science & Technology, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
pubmed:publicationType
Journal Article