Controlling anisotropic electrical conductivity in porous graphene-nanotube thin films

2020

Materials

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The development of electrochemical biosensors is an important challenge in modern biomedicine since they allow detecting femto- and pico-molar concentrations of molecules. During this study, pillared graphene structures supported by vertically aligned carbon nanotubes (VACNT-graphene) are examined as the potential recognition element of DNA biosensors. Using mathematical modeling methods, the atomic supercells of different (VACNT-graphene) configurations and the energy profiles of its growth are found. Regarding the VACNT(12,6)-graphene doped with DNA nitrogenous bases, calculated band structure and conductivity parameters are used. The obtained results show the presence of adenine, cytosine, thymine, and guanine on the surface of VACNT(12,6)-graphene significantly changes its conductivity so the considered object could be the prospective element for DNA biosensing.

Section: Methods and Resultsmentioning

confidence: 82%

Section: Construction Of Vacnt-graphene Atomic Supercellsmentioning

confidence: 99%

Pillared Graphene Structures Supported by Vertically Aligned Carbon Nanotubes as the Potential Recognition Element for DNA Biosensors

Shunaev

2020

Materials

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“…Nanomaterials 2021, 11, x FOR PEER REVIEW 2 of 10 the possibility to grow nanotubes of different chirality on its surface [23,24]. Earlier, authors of this study showed that that the growth of single-walled carbon nanotubes (6,6) and (9,9) in HG round-shaped holes with a size of approximately 0.8-1.2 nm was energetically favorable [25,26]. The aim of this work was to study the dependency of the electrical conductivity in the HG with round holes on the neck width.…”

Section: Methodsmentioning

confidence: 86%

“…Another advantage of HG with round holes is the possibility to grow nanotubes of different chirality on its surface [ 23 , 24 ]. Earlier, authors of this study showed that that the growth of single-walled carbon nanotubes (6,6) and (9,9) in HG round-shaped holes with a size of approximately 0.8–1.2 nm was energetically favorable [ 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

Holey Graphene: Topological Control of Electronic Properties and Electric Conductivity

Barkov

2021

Nanomaterials

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This paper studies holey graphene with various neck widths (the smallest distance between two neighbor holes). For the considered structures, the energy gap, the Fermi level, the density of electronic states, and the distribution of the local density of electronic states (LDOS) were found. The electroconductive properties of holey graphene with round holes were calculated depending on the neck width. It was found that, depending on the neck width, holey graphene demonstrated a semiconductor type of conductivity with an energy gap varying in the range of 0.01–0.37 eV. It was also shown that by changing the neck width, it is possible to control the electrical conductivity of holey graphene. The anisotropy of holey graphene electrical conductivity was observed depending on the direction of the current transfer.

“…The atomistic model of pillared graphene represents two sheets of monolayer graphene with SWCNTs (9,9) of 1.2 nm in diameter between them. These tubes were chosen for two reasons: (1) The tubes of this diameter are being synthesized most often; (2) earlier it was shown that the pillared graphene with tubes (9,9) is the most energetically favorable [45]. Two models that differ in the height of the tubes were built (Figure 1).…”

Section: Atomistic Modelsmentioning

confidence: 99%

Theoretical Study of a New Porous 2D Silicon-Filled Composite Based on Graphene and Single-Walled Carbon Nanotubes for Lithium-Ion Batteries

Kolosov

2020

Applied Sciences

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The incorporation of Si16 nanoclusters into the pores of pillared graphene on the base of single-walled carbon nanotubes (SWCNTs) significantly improved its properties as anode material of Li-ion batteries. Quantum-chemical calculation of the silicon-filled pillared graphene efficiency found (I) the optimal mass fraction of silicon (Si)providing maximum anode capacity; (II) the optimal Li: C and Li: Si ratios, when a smaller number of C and Si atoms captured more amount of Li ions; and (III) the conditions of the most energetically favorable delithiation process. For 2D-pillared graphene with a sheet spacing of 2–3 nm and SWCNTs distance of ~5 nm the best silicon concentration in pores was ~13–18 wt.%. In this case the value of achieved capacity exceeded the graphite anode one by 400%. Increasing of silicon mass fraction to 35–44% or more leads to a decrease in the anode capacity and to a risk of pillared graphene destruction. It is predicted that this study will provide useful information for the design of hybrid silicon-carbon anodes for efficient next-generation Li-ion batteries.