Anomalous Behaviors of Visible Luminescence from Graphene Quantum Dots: Interplay between Size and Shape
- 15 August 2012
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 6 (9), 8203-8208
- https://doi.org/10.1021/nn302878r
Abstract
For the application of graphene quantum dots (GQDs) to optoelectronic nanodevices, it is of critical importance to understand the mechanisms which result in novel phenomena of their light absorption/emission. Here, we present size-dependent shape/edge-state variations of GQDs and visible photoluminescence (PL) showing anomalous size dependences. With varying the average size (da) of GQDs from 5 to 35 nm, the peak energy of the absorption spectra monotonically decreases, while that of the visible PL spectra unusually shows nonmonotonic behaviors having a minimum at da = ∼17 nm. The PL behaviors can be attributed to the novel feature of GQDs, that is, the circular-to-polygonal-shape and corresponding edge-state variations of GQDs at da = ∼17 nm as the GQD size increases, as demonstrated by high-resolution transmission electron microscopy.Keywords
This publication has 32 references indexed in Scilit:
- Excitonic absorption in gate-controlled graphene quantum dotsPhysical Review B, 2010
- Triplet States and Electronic Relaxation in Photoexcited Graphene Quantum DotsNano Letters, 2010
- Hydrothermal Route for Cutting Graphene Sheets into Blue‐Luminescent Graphene Quantum DotsAdvanced Materials, 2010
- Graphene: Status and ProspectsScience, 2009
- The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbonsNature Materials, 2009
- Tuning of energy levels and optical properties of graphene quantum dotsPhysical Review B, 2008
- Chaotic Dirac Billiard in Graphene Quantum DotsScience, 2008
- Energy Band-Gap Engineering of Graphene NanoribbonsPhysical Review Letters, 2007
- The rise of grapheneNature Materials, 2007
- Energy Gaps in Graphene NanoribbonsPhysical Review Letters, 2006