Graphene - Science topic
Platform for anything related to graphene; its synthesis and applications
Questions related to Graphene
For modelling graphene, the CST software includes both a graphene and a graphene-Eps model. The graphene model expressed in the CST with a thickness of 0.3 nm is considered a single layer of graphene, while the graphene-EPS model is expressed as a multilayer of graphene sheets with a suitable thickness. Whenever I use the ''graphene-EPS'' model and increase the chemical potential, it does not affect any changes while using the "graphene'' model. Even at 0 eV chemical potential, it reflects all waves.Now my question is: why does it reflect all waves, even in insulting phases? I suspect that I may have made mistakes while creating the graphene material.
How to synthesis manganese doped graphene oxide after the synthe of graphene oxide by Hummers method ?
What will be the condition that s11 will be the same?
- I have tried to replace copper with graphene, but the results are very different.
- I also changed the chemical potential from 0.1eV to 0.5ev, but the results didn't match.
- Will the thickness of copper and graphene be the same?
- Is relaxation time have also any role to play in determining the s11.
I am very confused about the simulation of a graphene-based antenna. Can anybody help me with this concept? I appreciate any help anybody can provide.
We know various synthesis routes of graphene. Most of them lead by mechanical exfoliation. Is there any method developed to convert glucose directly into graphene?
I have come across a few articles where an effort was made to understand the effect of rhombohedral (ABC stacking) graphite effect on the li-ion battery performance. However, I have not found any work (academic or industrial) which precisely says why a certain kind (ABC vs ABAB) is more favourable, or with great conviction say: it doesn't matter and why.
Love to hear from my science and tech colleagues here about their thoughts. Also can you please tell me why and provide a reference?
Some references that I would like to mention:
What are the applications of deep learning, especially deep reinforcement learning, in nanotechnology, especially micro- and nanoelectronics? Please answer the question or recommend some articles.
- Piezoresitive flexible pressure sensors
- PDMS nanocomposites
- CNTs, Graphene, etc.
- Numerical model to predict the behaviour of flexible pressure sensors and porous flexible pressure sensor
- Simulation method for micro structures presence on conductive layer in flexible piezoresisitve pressure sensors
In this question, I am asking about the benefits of using graphene in construction projects. Graphene has been shown to offer superior strength, durability, and energy efficiency compared to other materials. Graphene is highly weather resistant, meaning construction projects can last longer and need less maintenance. Additionally, graphene is highly conductive, meaning that energy efficiency can be maximized in constructing buildings and other structures.
I was solving the tight binding model for graphene mono layer and found the zero band gaps at dirac points but then I saw some literatures stating that hBN which is a 2D material , also known as white graphene , has a BG of ~6ev , I am not able to understand what makes graphene different from hBN , is it the symmetry of Carbon atoms over B and N atoms or anything else ,Because tight binding model will apply the same way on hBN as in graphene
a. +4 is the place of co2 molecule in front of the graphene.
How the integral in equation 1 is calculated into equation 3 depicted in the attached picture using equation 2?
Dear all, I am evaluating the Young's modulus of graphene via Molecular Dynamics simulation with OPLS-AA potential. The method I am using is a tensile test by "pulling apart the opposite rows of carbon rings of a monolayer graphene sheet at a specified speed an registering the strain - potential energy curve.
Results are in good agreement with literature when I run the simulations at 300° K.
At 1 ° K I obtain results which are substantially similar to the ones at T = 300 °K. It seems to me that the OPLS-AA coefficients as generated by the LigParGen website, or found in literature, do no have any temperature dependent relationship. So I am not surprised to find results substantially independent from the temperature of the simulation. But I found a paper in which the authors sustain to have calculated graphene's modulus at 1°K and their data are different from mine, even when I apply exactly their MD procedure and conditions.
I am really puzzled. Any comment, suggestion or explanation would be very welcome. Thanks a lot
Do Graphene and its derivatives GO and rGO show antimicrobial properties when blended with polymer matrix ?
the atom of Carbon should be respect the Octet rule. But our professor tells us otherwise
I want to apologize if the answer to my question is already somewhere around, have been searching a lot and haven't found it yet.
I do a TBA on Graphene. Going through the article attached below, I got the hamiltonian's eigenvalues and eigenvectors, and calculated fermi velocity function near the K and K' points of the Graphene Brillouin zone. What I need to proceed with my calculations are wave functions of Graphene's pi and pi* orbitals. Now, I know that there is a LCAO method to achieve this, but despite going through a lot of articles, I have found only generic math and procedure explanations. As I am not that much into LCAO, can you please give me some hint how to apply it to Graphene (where to start)?
Thank you in advance,
I am working on graphene and CNT-based composites. out of the two, which has higher hardness value?
I want to synthesis graphene by co2 cw laser. I want to to know;
1. is there any specific polymer ?
2. what is suitable power and speed be used for this work ? (if u have any experience on cw co2 laser, it would make me happy to share it with me )
While synthesizing graphene oxide by modified Hummers method, I used HCl and acetone for washing purposes. When washing with acetone, while adding the acetone on to graphene oxide, it turns into a gel like product. I centrifuged it at 4000 rpm for 30 mins but so precipitation occurred. I don't know what happened. I was wondering, is there any way I can avoid such a gel like product?
We are working on metal oxide decorated on graphene oxide,
what was the solvent can we use for dissolving metal oxide decorated on graphene oxide.
We have tried DMSO, DMF and NMP, but it was not dissolved.
This GitHub repository (https://github.com/nuwan-d/fracture_of_grahene) contains a MATLAB script to generate the LAMMPS input files for the molecular dynamics simulation shown below. Additional MATLAB scripts are available to post-process the simulation outputs. This tutorial can be helpful to graduate students who are relatively new to MD simulations. Good luck!
Is it possible to fabricate "experimentally" graphene multi-layers with a thickness of 30 nm? What is the limitation of this thickness?
I have synthesized Ag-Go composite using chemical reduction method using NaBH4 as reducing agent. When I took the UV -VIS of the sample, I can observe only the characteristic peak of silver nanoparticle at around 420 nm. But, I couldn't observe any peak that determines the presence of Graphene oxide. Why is it so?
What kind of grids are used for TEM test of graphene oxide?
I synthesised graphene by using the electrochemical exfoliation method. How to calculate the weight of graphene for finding the specific capacitance of graphene?
The substrate used is a microscopic glass slide. rGO is dispersed in NMP (N-Methyl-2-pyrrolidone) to form a dispersed solution. What is the best suited deposition technique to obtain an even deposition of rGO on the glass substrate? Should we use hydrophilic glass substrates or hydrophobic glass substrates?
rGO was obtained by reducing GO that was synthesized by modified hummers method. If it is possible to produce thin flakes of rGO from a bult rGO, how could we characterize so that I can prove the presence of thin flakes?
Hello, for a research project, I need to composite graphene oxide with a ceramic powder and sinter it at 1300 degrees under vacuum and argon gas. Does graphene oxide disappear?
In recent days, batteries have a lot of attention, especially for Electric vehicles. Besides Li-ion Battery, I've read about aluminium ion batteries, but I can't understand, Why aluminium act as an anode and cathode uses graphene?
I treated PLLA/Graphene composite with 1m NaOH solution in different times.
I expected increasing time of NaOH treatment make composite more hydrophile and decrease contact angle. but contact angle increased.
could anyone help me to realize how this happened.
thanks in advance.
we got many peaks, actually graphene oxide have the first peak in 10.06 (2Theta), is that GO formed? or if not what is the reason?
The layered materials, also called the van der Waals (vdWs) materials, are those having strong in-plane bonding and weak vdWs interactions in out-of-plane directions (e.g. graphene or h-BN). The in-plane electrical conduction/conductivity is justified by the movement of "free" electrons through bonds but how these electrons conduct through the out-of-plane directions as there are only weak interactions present? Do electron move by the phenomenon of hopping? and if there is hopping which type of hopping would be this? What would be the range of hopping (At which distance electrons can exhibit the hopping phenomenon)?
to be used in PSF file, the atom type of oxygen in Graphene_oxide shoulde be known! or how can I make the psf file by making the pdb file manually!!?
I have a question about fixing graphene oxide sheet for simulation with gromacs
I used three methods to MD Simulation of graphene oxide, but unfortunately, in the next stage, I encountered problems with nvt and npt step.
In the first method, I used the strong position restrained and used the command, however, I encountered the collapse of the graphene oxide sheets.
In the second method, I used the option of freezing and fixing the graphene oxide screen and modified the parameters related to mdp file, in which case I should have used the group algorithm instead of verlet, which is obsolete according to the new versions of Gromacs.
In the third method, I used the method of setting non-banded parameters to zero, which was mentioned in the articles, but again, the results were not acceptable.
Thank you for helping me if you have experience in this field.
I guess we can change the parameters in GULP very easily to match with AIREBO. Notice the changes in both REBO and AIREBO potential in LAMMPS database. I am attaching LAMMPS file. So GULP has already brenner.F90, brennermd.F90 and brennerd.F90 and changes in the parameters are to be done accordingly. But I cannot find a way as to where these changes are to be done ?
Should I need to create my own new library file in GULP and call it from script file?
Has anyone encountered such procedure ?
CIF file of a graphene nanotube?
Could someone help me with a suitable process with doping graphene? As I read from many papers, graphene needs to be ultrasonicated to eliminate the solvent (alcohol) before being doped into the polymers gel.
However, if I directly buy the powder graphene, can I directly pour it into the polymers?
I have prepared graphene oxide by modified Hummer's Method and after drying it in an oven, it has dried out in a sheet form. But I want to make graphene oxide powder. How can I make it powder from a sheet form ?
I want to calculate the magnetic field parameters in the twisted bilayer graphene, which approach would be more suitable for the same?
Graphene materials synthesis from organic waste and their application in emerging contaminants removal.
I read on paper that graphene foam need to fix on glass slide before immerse into the solution during hydrothermal method. May I know how to make sure that the graphene foam is stick/fix to the glass slide?
I'm going to make a graphene aerogel-coated electrode that substrate is copper foam, but I can't coat a uniform layer of it in the case of loading less than 5 mg slurry. I would appreciate it if you share your experiences about this matter.
I have synthesized convert graphite to graphene oxide(GO) and then GO to reduced graphene oxide(rGO) using the modified Hummer method. During PXRD characterization I found that GO XRD peak comes very intense, sharp but rGO XRD peak comes weak, less intense and broad. Why?
Hello, fellow scientists. Resently I have been experimenting on PMMA/Graphene composites. I have obtained a flexural strength of ~40MPa and a flexural modulus of ~2500MPa under the following conditions: 120°C, 50PSI, 1h air curing; obtaining bubble free Samples. I have been reading several papers that report higher flexural properties but I have no idea were I am making a mistake or missing details. I was thinking in adding some EGMMA as co-monomer. Is there any way to increase flexural properties without adding additives? Greetings!
What type of oxide was formed during wear test of Aluminum MMCs reinforced with cerium oxide and graphene ?
I treated graphene nanoplatelets (GNP, C-750) by sonicating them with a mixture of 50%H2SO4/50%HNO3 (3:1) and washed repeatedly with water until neutral. The idea was to introduce oxygenated functional groups (as -COOH and -OH) on the surface of the graphene layers as confirmed by XPS and XRD. However, when I recorded the RAMAN spectra of both GNP and ox-GNP, the ID/IG value of the acid-treated graphene was lower than the pristine GNP!!!
For GNP: ID/IG=0.72
For acid-treated GNP: ID/IG=0.66
When obtaining a composite based on graphene oxide and ceramic oxides, a dark brown powder is formed. obviously graphene oxide is there. However, only ceramic peaks are present in the diffraction patterns of such samples. The graphene oxide reflection appears only in samples with very high carbon content. Please, help me explain this phenomenon.
I want to analyze Graphene oxide by XRD and I want to use 0.02 degrees for step size. the rang of 2 theta is 5-80 degrees but I can not calculate the scan step time.
AssalamoAlaikum Hello Everyone hope you are doing well.
Yesterday I received an email from my supervisor in which he mentioned that to make a new proposal on the Topic of CO2 storage/capture as impurity by using GO (graphene oxide). I haven't worked on it. Could you suggest me some articles that are related to the topic and helpful to understand the topic. Actually I have to submit it in next 5 days so please if you have some information please guide me on this topic.
I am highly thankful to all of you for your time and suggestions (in advance)
I would like to ask about the best conditions of sonication of graphite oxide in terms of apparatus (probe or bath), time and power in order to effectively exfoliate the graphite oxide without damaging the structure of GO sheets. The objective is to obtain water dispersion of about 5 mg/mL of the highest possible quality.
Thank you very much.
Is is good to have high moisture retention capacity of polymer film in packaging application.
What is the reason of higher MRC of Graphene oxide/PVA film then neat PVA film ??
Si nanoparticles are insoluble in water while Graphene oxide(GO) is highly soluble in water. For preparing a nanocomposite of Si/GO what are the solvents used for dispersing the two precursors separately before mixing them together.
Thanks and regards
Hi everyone. The reported photo refer to graphite flakes exfoliated by a chemo-mechanical method. I would like to know if the observed structures could be identified with few- or mono-layer graphene nanosheets. Or in other words, do graphene nanosheets exhibit similar topology under cross polarizers?
Image A and B shows a wide field view (scale bars 200 and 40 um, respectively)
While C and D compare the same site, with polarizers at 90 and 78 degrees respectively (scale bar 50 um).
It is possible to see how as polarizers are rotated from the 90 position, the observed features seems progressively to "vanish"...
In literature I found prevalently optical images of graphenes with lateral size in the order of nanometres, but not in the order of microns, therefore I wanted to ask. Every feedback, answer will be of big help and very appreciated. Thank you all in advance.
I came across this video, https://www.youtube.com/watch?v=hKoXk9s2LI8 which discusses on preparation of graphene foam with just sugar and Ammonium Chloride. Has anyone tried this method? Also, please tell me number of graphene layers presented in the final product.
I want to know what's different between bilayer and few layer graphene uv spectra (absorption wavelength)?
I am panning to make Graphene Oxide following the methodology on the paper https://www.youtube.com/watch?v=sTooYDp1KD4 (explanation given by Professor James Tour himself) caught my attention. Since, I am working at a new lab, I don't want to cause any trouble while following this procedure.
Please share with me if you have faced any problems while following this procedure and also suggest me the improvisations if you have any.
Sometimes it's reported brownish in colour. I would like understand the reason for the colour formation.
GO is brown in colour and water soluble and rGO is black in colour but which analytical tools help to distinguish between both.
I'm trying to calculate graphene doping on some substrate. The whole question is in case 3 paragraph and case 1 and 2 are just to show that calculations make physical sense.
CASE 1: graphene on semiconductor. Distance between graphene and substrate is about 3.1 angstroms. There is no doping. The dos graphene cone is in the middle of semiconductor band gap and everything is fine.
CASE 2: graphene on the same substrate but there is a monovacancy on the substrate surface in the supercell. The substrate becomes metallic due to dangling bond. The graphene cone shifts toward valence band of the substrate and according to the Fermi level there is a p-doping of graphene by ~0.5 eV.
CASE 3: I shift the same optimized graphene by 15 angstroms from substrate slab to be sure there is no interaction. Of cource the periodic images of the supercell are also separated by 15 ang vacuum. I expect that because there is no interaction between graphene and substrate there is no doping but I'm wrong! The graphene is still p-doped by 0.4 eV and this shift doesn't depend on the distance between graphene and substrate. Why?
The pdos of the heterostructures are illustrated in case123.jpg file.
The results are similar for vasp and siesta so the issue probably is related not to a dft package but to the way how in dft occupancies are determined. Does it mean that dft considers the whole electrons as "shared" electrons and place part of graphene electrons on to valence states of the substrate despite the graphene is far from it. And thereby there is a fiction doping?
Thank you in advance if you can explain my results to me)
Please assist me how can i import or manufacture Graphene layer into Comsol software?
I'm looking at and trying to interpret XPS data from this paper:
The paper looks at oxidation of graphite through thermal treatment which is relevant to my future research... I'm a bit confused at why sp3 - carbon bonds are present in pristine graphite at 61.4% when I always thought that graphite was sp2 hybridised?
This sp3-C group disappears after thermal treatment (at 1000 Celsius for 10 mins) and is replaced by sp2-C group of 88.5%.
Can anyone help me understand why sp3 bonds are appearing (like in diamond) and will this affect its electrical conductivity?
Thanks for any help,
In the world wide, researcher select 0.1 wt% for graphene as nano dispersion in PCM, but not prove or determined the ratio.
I would like to create a well-mixed solution of 6-10 wt% polyetherimide (PEI) and 0.5-3 wt% graphene oxide (GO). What solvent would best help me achieve this mixture?
I welcome any other general suggestions for creating a PEI/GO solution mix with good GO dispersion.
I want to synthesize a few layer graphene by CVD method and using of zinc oxide powder as a catalyst substrate.
I need a reference for kinetic growth of graphene by zinc oxide powder as catalyst but I couldn't find such an article.
I am planning to conduct MD simulation research in graphene and I wanted to know why (111) surface of substrates are preferred for graphene deposition.
Hello Dear researchers,
I'm seeking to simulate a graphene oxide nanoparticle with protein. I wish to do so by simulating them with the Gromacs programme, but I have no idea how to carry out the simulation of protein-containing nanoparticles. Please recommend any tutorials or research articles to me. I have already performed the simulation of protein and ligand complex.
There is already a large number of literature on graphene oxide stating that the number of epoxy groups is quite similar to the number of ethyl groups. However, I was wondering if the number of carboxyl groups attached to the edges of the graphene oxide is either more or less than these groups attached to the basal plane of the graphene oxide. Or does it usually depends on the process of synthesis of graphene oxide?
I am only looking into the perspective of these three major functional groups present in graphene oxide. Although, I know that many functional groups can be present in graphene oxide.
I am trying to pill of graphite to get few layer of graphene using the scotch tape. But unable to get any thing and don,t know how this layer can be transferred to the glass from the tape. Can resistance of graphene layers measure by the simple multi meter. If yes what will be the range of the resistance in ohm. Help is appreciated.
I have made a polymer nanofiber nanocomposite in which I have added graphene oxide. I can't see the graphene oxide in my SEM and TEM photos. To make sure that there is graphene oxide in the composition, I used the FTIR test, where the peaks related to graphene oxide were observed. Can anyone help me with what is the way to visually see the graphene oxide?
thanks in advance
In many researches, plain sand and GO-coated sand almost show similar efficiency. why people did not discuss clearly the efficiency of plain sand in their researches. ?