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The Effects of Aging on the Luminescence of PEG-Coated Water-Soluble ZnO Nanoparticle Solutions

Authors :
Alan G. Joly
Wei Chen
Ramaswami Sammynaiken
Boon Kuan Woo
Source :
The Journal of Physical Chemistry C. 112:14292-14296
Publication Year :
2008
Publisher :
American Chemical Society (ACS), 2008.

Abstract

Water-soluble ZnO nanoparticles coated with polyethylene glycol biscarboxymethyl (PEG(COOH)2) were prepared in ethanol/water solutions. The ZnO nanoparticles have a hexagonal structure with an average size of 10 nm. Three different luminescence bands are observed from the nanoparticle solutions: green emission at 530 nm from surface states or defects, UV emission at 380 nm from the ZnO exciton, and an emission band at around 338 nm from the PEG(COOH)2. The fresh as-prepared samples have very strong green emission at 530 nm from surface states or defects but very weak excitonic emission at 380 nm. After dilution with ethanol, the green emission decreases in intensity and the excitonic emission increases. In the diluted samples, the excitonic luminescence intensity increases with storage time. This intensity increase is attributed to surface passivation by CH3COO− ligands resulting from precursor reactions in the ethanol solvent.

Details

ISSN :
19327455 and 19327447
Volume :
112
Database :
OpenAIRE
Journal :
The Journal of Physical Chemistry C
Accession number :
edsair.doi...........ed5d6ce802a9b42238851eb8d2d92518
Full Text :
https://doi.org/10.1021/jp803649k