Evidence for Edge‐State Photoluminescence in Graphene Quantum Dots |
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Authors: | Kiran Lingam Ramakrishna Podila Haijun Qian Steven Serkiz Apparao M. Rao |
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Affiliation: | 1. Department of Physics and Astronomy, Clemson University, , Clemson, SC, 29634 USA;2. Electron Microscope Facility, Clemson Research Park, Clemson University, , Anderson, SC, 29625 USA;3. Savannah River National Laboratory, , Aiken, SC, 29808 USA;4. Center for Optical Materials Science and Engineering Technologies, Clemson University, , Clemson, SC, 29634 USA |
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Abstract: | For a practical realization of graphene‐based logic devices, the opening of a band gap in graphene is crucial and has proven challenging. To this end, several synthesis techniques, including unzipping of carbon nanotubes, chemical vapor deposition, and other bottom‐up fabrication techniques have been pursued for the bulk production of graphene nanoribbons (GNRs) and graphene quantum dots (GQDs). However, only limited progress has been made towards a fundamental understanding of the origin of strong photoluminescence (PL) in GQDs. Here, it is experimentally shown that the PL is independent of the functionalization scheme of the GQDs. Following a series of annealing experiments designed to passivate the free edges, the PL in GQDs originates from edge‐states, and an edge‐passivation subsequent to synthesis quenches the PL. The results of PL studies of GNRs and carbon nano‐onions are shown to be consistent with PL being generated at the edge sites of GQDs. |
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Keywords: | graphene quantum dots photoluminescence edge‐states |
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