Revealing the tunable photoluminescence properties of graphene quantum dots
Sk, Mahasin Alam
Lim, Kok Hwa
Date of Issue2014
School of Chemical and Biomedical Engineering
Graphene quantum dots (GQDs) are a new class of fluorescent reporters promising various novel applications including bio-imaging, optical sensing and photovoltaics. They have recently attracted enormous interest owing to their extraordinary and tunable optical, electrical, chemical and structural properties. The widespread use of GQDs, however, is hindered by the current poor understanding of their photoluminescence (PL) mechanisms. Using density-functional theory (DFT) and time-dependent DFT calculations, we reveal that the PL of a GQD can be sensitively tuned by its size, edge configuration, shape, attached chemical functionalities, heteroatom doping and defects. In addition, it is discovered that the PL of a large GQD consisting of heterogeneously hybridized carbon network is essentially determined by the embedded small sp2 clusters isolated by sp3 carbons. This study not only provides explanation to the previous experimental observations but also provides insightful guidance to develop methods for controllable synthesis and engineering of GQDs.
Journal of materials chemistry C
© 2014 The Royal Society of Chemistry. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Material Chemistry C, The Royal Society of Chemistry. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: http://dx.doi.org/10.1039/C4TC01191K.