Next Article in Journal
Mechanical Modelling of the Plastic Flow Machining Process
Next Article in Special Issue
Energy Transfer from Photosystem I to Thermally Reduced Graphene Oxide
Previous Article in Journal
Composite Bonding Pre-Treatment with Laser Radiation of 3 µm Wavelength: Comparison with Conventional Laser Sources
Previous Article in Special Issue
In Situ Room Temperature Electron-Beam Driven Graphene Growth from Hydrocarbon Contamination in a Transmission Electron Microscope
Open AccessArticle

Interband Absorption in Few-Layer Graphene Quantum Dots: Effect of Heavy Metals

1
Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden
2
Frantsevich Institute for Problems of Materials Science, NASU, 142 Kyiv, Ukraine
*
Author to whom correspondence should be addressed.
Materials 2018, 11(7), 1217; https://doi.org/10.3390/ma11071217
Received: 26 June 2018 / Revised: 12 July 2018 / Accepted: 13 July 2018 / Published: 16 July 2018
(This article belongs to the Special Issue Carbon Nanomaterials: Graphene, Nanoribbons and Quantum dots)
Monolayer, bilayer, and trilayer graphene quantum dots (GQDs) with different binding abilities to elemental heavy metals (HMs: Cd, Hg, and Pb) were designed, and their electronic and optical properties were investigated theoretically to understand deeply the optical response under heavy metal exposure. To gain insight into the nature of interband absorption, we performed density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations for thickness-varying GQDs. We found that the interband absorption in GQDs can be efficiently tuned by controlling the thickness of GQDs to attain the desirable coloration of the interacting complex. We also show that the strength of the interaction between GQDs and Cd, Hg, and Pb is strongly dependent on the number of sp2-bonded layers. The results suggest that the thickness of GQDs plays an important role in governing the hybridization between locally-excited (LE) and charge-transfer (CT) states of the GQDs. Based on the partial density-of-states (DOS) analysis and in-depth knowledge of excited states, the mechanisms underlying the interband absorption are discussed. This study suggests that GQDs would show an improved sensing performance in the selective colorimetric detection of lead by the thickness control. View Full-Text
Keywords: DFT; few-layer graphene quantum dots; heavy metals; interaction; absorption spectroscopy; DOS DFT; few-layer graphene quantum dots; heavy metals; interaction; absorption spectroscopy; DOS
Show Figures

Figure 1

MDPI and ACS Style

Shtepliuk, I.; Yakimova, R. Interband Absorption in Few-Layer Graphene Quantum Dots: Effect of Heavy Metals. Materials 2018, 11, 1217.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop