Ghosh, Siddharth and Awasthi, Manohar and Ghosh, Moumita and Seibt, Michael and Niehaus, Thomas A. (2016) Graphene quantum dots with visible light absorption of the carbon core: insights from single-particle spectroscopy and first principles based theory. 2D MATERIALS, 3 (4): 041008. ISSN 2053-1583,
Full text not available from this repository. (Request a copy)Abstract
Luminescent carbon nanodots (CND) are a recent addition to the family of carbon nanostructures. Interestingly, a large group of CNDs are fluorescent in the visible spectrum and possess single dipole emitters with potential applications in super-resolution microscopy, quantum information science, and optoelectronics. There is a large diversity of CND's size as well as a strong variability of edge topology and functional groups in real samples. This hampers a direct comparison of experimental and theoretical findings that is necessary to understand the unusual photophysics of these systems. Here, we derive atomistic models of finite sized (<2.5 nm) CNDs from high resolution transmission electron microscopy (HRTEM) which are studied using approximate time-dependent density functional theory. The atomistic models are found to be primarily two-dimensional (2D) and can hence be categorised as graphene quantum dots (GQD). The GQD model structures that are presented here show excitation energies in the visible spectrum matching previous single GQD level photoluminescence studies. We also present the effect of edge hydroxyl and carboxyl functional groups on the absorption spectrum. Overall, the study reveals the atomistic origin of CNDs photoluminescence in the visible range.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | NANODOTS; FLUORESCENCE; NANORIBBONS; ARMCHAIR; ZIGZAG; EDGES; PHOTOLUMINESCENCE; NANOCRYSTALS; NANOFLAKES; MICROSCOPY; carbon nanodots; graphene quantum dots; single-particle spectroscopy; photoluminescence; high resolution transmission electron microscopy; time-dependent density functional based tight binding (TD-DFTB) |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 04 Apr 2019 07:26 |
| Last Modified: | 04 Apr 2019 07:26 |
| URI: | https://pred.uni-regensburg.de/id/eprint/3811 |
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