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

Abstract

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:

Elvati, Paolo  ^[1];

• Search DOE PAGES for author "Elvati, Paolo"
• Search DOE PAGES for ORCID "0000-0002-6882-6023"

Baumeister, Elizabeth ^[2]; Violi, Angela  ^[3]

• Search DOE PAGES for author "Violi, Angela"
• Search DOE PAGES for ORCID "0000-0001-9517-668X"

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+ Show Author Affiliations

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:

Tue Mar 21 00:00:00 EDT 2017

Research Org.:

Univ. of Michigan, Ann Arbor, MI (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1430214

Grant/Contract Number:  

SC0002619

Resource 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

Country of Publication:

United States

Language:

English

Subject:

77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY