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Title: Graphene quantum dots: effect of size, composition and curvature on their assembly

Graphene Quantum Dots (GQDs) are a relatively new class of molecules that have ignited tremendous research interest due to their extraordinary and tunable optical, electrical, chemical and structural properties. In this paper, we report a molecular-level elucidation of the key mechanisms and physical–chemical factors controlling the assembly and stability of nanostructures formed by GQDs in an aqueous environment, using molecular dynamics simulations. We observe the general tendency to form small aggregates and three recurring configurations, one of them with a single layer of water separating two GQDs. The type and characteristics of the structure are mostly determined by the hydrophobicity of the GQDs as well as the steric hindrance of the dangling groups. The composition of the terminal groups plays a key role in determining the configuration of the GQDs, which is also markedly affected by the formation of clusters. Notably, the aggregated GQDs assume strongly correlated shapes and, in some cases, display a radically different conformation distribution compared to single molecules. This cooperative effect prolongs the lifetime of the GQD configurations and can explain the observed persistence of chiral conformations that are only marginally more stable than their specular images.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [3]
  1. Univ. of Michigan, Ann Arbor, MI (United States). Mechanical Engineering
  2. Univ. of Michigan, Ann Arbor, MI (United States). Chemical Engineering
  3. Univ. of Michigan, Ann Arbor, MI (United States). Mechanical Engineering, Chemical Engineering and Biophysics program and Macromolecular Science and Engineering
Publication Date:
Grant/Contract Number:
SC0002619
Type:
Accepted Manuscript
Journal Name:
RSC Advances
Additional Journal Information:
Journal Volume: 7; Journal Issue: 29; Journal ID: ISSN 2046-2069
Publisher:
Royal Society of Chemistry
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1430214