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ID 48647
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creator
Iwasaki, Hideharu
Aishima, Kana
Iskandar, Ferry
Wang, Wei-Ning
Takimiya, Kazuo
abstract
A facile, economic and environmentally friendly one-step approach for the preparation of highly luminescent graphene quantum dots (GQDs) was developed using a hydrothermal reaction between citric acid and urea. Unlike previous reports, we focused on the effect of the transient nature of GQD formation on the photoluminescence (PL) properties and molecular structure changes of the products. We found that the GQDs have an optimum reaction time and require an effective precursor to achieve excellent luminescent properties. The PL, ultraviolet-visible (UV-vis) absorption, zeta potential, and nuclear magnetic resonance (NMR) analyses of the GQDs prepared at various reaction times revealed that the molecular structures responsible for the luminescence of the GQDs are aggregates or condensation products of citric acid amides. We found that urea addition to the precursor drastically enhances the PL intensity of the GQDs, and it is 40 times higher than those prepared using the pure citric acid precursor. Additionally, a GQDs–polyvinyl alcohol composite achieved an excellent quantum yield (QY) of 43.6%.
description
This work was supported by JSPS KAKENHI Grant numbers 26709061 and 24656413. We thank Dr Eishi Tanabe from the Hiroshima Prefectural Institute of Industrial Science and Technology for helping with TEM analyses, and Drs Naoya Tochio and Junichi Kakimura from Hiroshima University for NMR analyses.
journal title
RSC Advances
volume
Volume 4
issue
Issue 99
start page
55709
end page
55715
date of issued
2014-10-21
publisher
Royal Society of Chemistry
issn
2046-2069
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
This journal is © The Royal Society of Chemistry 2014.
relation url
department
Graduate School of Engineering