Limits...
Theoretical Investigations of Optical Origins of Fluorescent Graphene Quantum Dots.

Wang J, Cao S, Ding Y, Ma F, Lu W, Sun M - Sci Rep (2016)

Bottom Line: Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized.The recombination of excited, well-separated electron-hole (e-h) pairs can result in enhanced fluorescence.This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Department of Physics, Liaoning University, Shenyang 110036, PR China.

ABSTRACT
The optical properties of graphene quantum dots (GQDs) were investigated theoretically. We focused on the photoinduced charge transfer and electron-hole coherence of single-layer graphene in the electronic transitions in the visible regions. Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized. The recombination of excited, well-separated electron-hole (e-h) pairs can result in enhanced fluorescence. This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs.

No MeSH data available.


The models used for the calculations.(a) GQD and (b) SF-GQD with -NH2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4837401&req=5

f1: The models used for the calculations.(a) GQD and (b) SF-GQD with -NH2.

Mentions: The models used for the calculations can be seen in Fig. 1(a,b), which show a GQD and an SF-GQD with -NH2, respectively. In mode (a), there are four zigzag edges and one armchair edge. The calculated absorption spectra of both GQDs in the visible region are presented in Fig. 2 and demonstrate that the optical absorption peaks of SF-GQD with -NH2 groups are significantly red shifted. This finding indicated that the fluorescence peaks of SF-GQD with -NH2 should also be significantly red shifted. These red-shift phenomena are consistent with the experimental findings131921.


Theoretical Investigations of Optical Origins of Fluorescent Graphene Quantum Dots.

Wang J, Cao S, Ding Y, Ma F, Lu W, Sun M - Sci Rep (2016)

The models used for the calculations.(a) GQD and (b) SF-GQD with -NH2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837401&req=5

f1: The models used for the calculations.(a) GQD and (b) SF-GQD with -NH2.
Mentions: The models used for the calculations can be seen in Fig. 1(a,b), which show a GQD and an SF-GQD with -NH2, respectively. In mode (a), there are four zigzag edges and one armchair edge. The calculated absorption spectra of both GQDs in the visible region are presented in Fig. 2 and demonstrate that the optical absorption peaks of SF-GQD with -NH2 groups are significantly red shifted. This finding indicated that the fluorescence peaks of SF-GQD with -NH2 should also be significantly red shifted. These red-shift phenomena are consistent with the experimental findings131921.

Bottom Line: Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized.The recombination of excited, well-separated electron-hole (e-h) pairs can result in enhanced fluorescence.This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Department of Physics, Liaoning University, Shenyang 110036, PR China.

ABSTRACT
The optical properties of graphene quantum dots (GQDs) were investigated theoretically. We focused on the photoinduced charge transfer and electron-hole coherence of single-layer graphene in the electronic transitions in the visible regions. Surface functionalization with donor or acceptor groups produced a red shift in the absorption spectrum, and electrons and holes were highly delocalized. The recombination of excited, well-separated electron-hole (e-h) pairs can result in enhanced fluorescence. This fluorescence enhancement by surface functionalization occurs because of the decreased symmetry of the graphene resulting from the roughened structure of the surface-functionalized GQDs.

No MeSH data available.