Linked Life Data

19606145

Source:http://linkedlifedata.com/resource/pubmed/id/19606145

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7253
pubmed:dateCreated
2009-7-16
pubmed:abstractText
In traditional photoconductors, the impinging light generates mobile charge carriers in the valence and/or conduction bands, causing the material's conductivity to increase. Such positive photoconductance is observed in both bulk and nanostructured photoconductors. Here we describe a class of nanoparticle-based materials whose conductivity can either increase or decrease on irradiation with visible light of wavelengths close to the particles' surface plasmon resonance. The remarkable feature of these plasmonic materials is that the sign of the conductivity change and the nature of the electron transport between the nanoparticles depend on the molecules comprising the self-assembled monolayers (SAMs) stabilizing the nanoparticles. For SAMs made of electrically neutral (polar and non-polar) molecules, conductivity increases on irradiation. If, however, the SAMs contain electrically charged (either negatively or positively) groups, conductivity decreases. The optical and electrical characteristics of these previously undescribed inverse photoconductors can be engineered flexibly by adjusting the material properties of the nanoparticles and of the coating SAMs. In particular, in films comprising mixtures of different nanoparticles or nanoparticles coated with mixed SAMs, the overall photoconductance is a weighted average of the changes induced by the individual components. These and other observations can be rationalized in terms of light-induced creation of mobile charge carriers whose transport through the charged SAMs is inhibited by carrier trapping in transient polaron-like states. The nanoparticle-based photoconductors we describe could have uses in chemical sensors and/or in conjunction with flexible substrates.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1476-4687
pubmed:author
pubmed:issnType
Electronic
pubmed:day
16
pubmed:volume
460
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
371-5
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Photoconductance and inverse photoconductance in films of functionalized metal nanoparticles.
pubmed:affiliation
[1] Department of Chemistry, [2] Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
pubmed:publicationType
Journal Article