Overcoming the Phase Inhomogeneity in Chemically Functionalized Graphene: The Case of Graphene Oxides

Huang, Bing; Xiang, Hongjun; Xu, Qiang; Wei, Su‐Huai

doi:10.1103/physrevlett.110.085501

Cited by 52 publications

(51 citation statements)

References 34 publications

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“…The kinetics of agglomeration is governed by diffusion processes, and in case of isolated epoxide and hydroxyl groups on graphene, their diffusion rates are controlled by migration energies of 0.8 eV and 0.5 eV, respectively (ESI). A number of DFT studies have addressed the diffusion and interaction of epoxide and hydroxyl species on graphene, and the results thus far discussed are in agreement with these recent computational works2537394042475253545556. Here, we address in detail the effects played by agglomeration phenomena onto the chemical stability and structure of GO.…”

Section: Resultssupporting

confidence: 79%

Origin of the Chemical and Kinetic Stability of Graphene Oxide

Zhao

Bongiorno

2013

Sci Rep

177

155

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At moderate temperatures (≤ 70°C), thermal reduction of graphene oxide is inefficient and after its synthesis the material enters in a metastable state. Here, first-principles and statistical calculations are used to investigate both the low-temperature processes leading to decomposition of graphene oxide and the role of ageing on the structure and stability of this material. Our study shows that the key factor underlying the stability of graphene oxide is the tendency of the oxygen functionalities to agglomerate and form highly oxidized domains surrounded by areas of pristine graphene. Within the agglomerates of functional groups, the primary decomposition reactions are hindered by both geometrical and energetic factors. The number of reacting sites is reduced by the occurrence of local order in the oxidized domains, and due to the close packing of the oxygen functionalities, the decomposition reactions become – on average – endothermic by more than 0.6 eV.

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Section: Resultssupporting

confidence: 79%

Origin of the Chemical and Kinetic Stability of Graphene Oxide

Zhao

Bongiorno

2013

Sci Rep

177

155

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“…In the former, the oxygen functionalities are randomly distributed across the graphene plane, while in the latter, the oxygen groups diffuse and form distinct clusters. Although we know that such a process is energetically favorable from our previous work 31,40 and other literature, 35,41,42 what exactly happens to the surface chemistry upon clustering, i.e. , changes in the relative concentration of oxygen functional groups, remains unknown to date.…”

Section: Resultsmentioning

confidence: 94%

Enhanced Cell Capture on Functionalized Graphene Oxide Nanosheets through Oxygen Clustering

Bardhan

Kumar

et al. 2017

ACS Nano

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With the global rise in incidence of cancer and infectious diseases, there is a need for the development of techniques to diagnose, treat, and monitor these conditions. The ability to efficiently capture and isolate cells and other biomolecules from peripheral whole blood for downstream analyses is a necessary requirement. Graphene oxide (GO) is an attractive template nanomaterial for such biosensing applications. Favorable properties include its two-dimensional architecture and wide range of functionalization chemistries, offering significant potential to tailor affinity toward aromatic functional groups expressed in biomolecules of interest. However, a limitation of current techniques is that as-synthesized GO nanosheets are used directly in sensing applications, and the benefits of their structural modification on the device performance have remained unexplored. Here, we report a microfluidic-free, sensitive, planar device on treated GO substrates to enable quick and efficient capture of Class-II MHC-positive cells from murine whole blood. We achieve this by using a mild thermal annealing treatment on the GO substrates, which drives a phase transformation through oxygen clustering. Using a combination of experimental observations and MD simulations, we demonstrate that this process leads to improved reactivity and density of functionalization of cell capture agents, resulting in an enhanced cell capture efficiency of 92 ± 7% at room temperature, almost double the efficiency afforded by devices made using as-synthesized GO (54 ± 3%). Our work highlights a scalable, cost-effective, general approach to improve the functionalization of GO, which creates diverse opportunities for various next-generation device applications.

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“…The ease with which graphene can be functionalized with hydrogen [3][4][5], oxygen [6][7][8], and metal atoms [9][10][11] has further added a new dimension into its potential for novel applications. Atomic layer deposition (ALD) is an efficient surface controlled thin film growth technique that is often used to deposit metal atoms on graphene [12].…”

Section: Introductionmentioning

confidence: 99%

Tailoring Li adsorption on graphene

et al. 2014

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The technological potential of functionalized graphene has recently stimulated considerable interest in the study of the adsorption of metal atoms on graphene. However, a complete understanding of the optimal adsorption pattern of metal atoms on a graphene substrate has not been easy because of atomic relaxations at the interface and the interaction between metal atoms. We present a partial particle swarm optimization technique that allows us to efficiently search for the equilibrium geometries of metal atoms adsorbed on a substrate as a function of adatom concentration. Using Li deposition on graphene as an example we show that, contrary to previous works, Li atoms prefer to cluster, forming four-atom islands, irrespective of their concentration. We further show that an external electric field applied vertically to the graphene surface or doping with boron can prevent this clustering, leading to the homogeneous growth of Li.

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Overcoming the Phase Inhomogeneity in Chemically Functionalized Graphene: The Case of Graphene Oxides

Cited by 52 publications

References 34 publications

Origin of the Chemical and Kinetic Stability of Graphene Oxide

Origin of the Chemical and Kinetic Stability of Graphene Oxide

Enhanced Cell Capture on Functionalized Graphene Oxide Nanosheets through Oxygen Clustering

Tailoring Li adsorption on graphene

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