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We are coating graphene based materials on SPE. How we can clean this screen printed electrodes for further use?
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There are three methods available for cleaning SPE before use. These are:
Process 1: 5 min. sonication of electrodes in 100% ethanol in a water bath.
Process 2: application of 1.5 ml of piranha solution (3:7 30% (v/v) H2O2 and 98% (v/v) H2SO4) on each working electrode for 2 min (please note that piranha solution is highly corrosive), followed by washing with deionized H2O.
Process 3: Electrode cleaning in 0.1 M H2SO4 for 10-15 cycles at a scan rate of 0.05 V/s from -1.0 V to 1.0 V, followed by deionized water washing and nitrogen drying.
CV cleaning is the optimum cleaning method which yield a smooth surface. Sonication is also a good cleaning method.
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I'm going to extend my research for turning biochar derived from biomass into graphene. But I'm in the early stages of the project and involving in collecting materials and articles to broaden my knowledge scope in this area of science. I completely know about pyrolysis process and turning the biomass into biochar. So, I need to have some further information on the conditions needed to produce graphene from biochar like type of the reactor, Temperature, Catalyst and etc. Also, I would appreciate, if you could let me know about the Latest Projects and new ideas of researchers and also give me some feedback on this research.
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I have a graphene-based material with secondary amine groups and carboxyl groups. I deposited antibodies in buffer solution onto the graphene and let sit at 4 C for 48 hr. Would the antibodies covalently bind to the graphene?
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If course if you have the aforementioned functional groups, there will be formation of an amide from the reaction between acid-amine groups. My Regards
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Want to design a graphene microstrip patch antenna.Thanks in advance.
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to simulate a graphene-based antenna using HFSS, That's what you should do:
1. Calculate conductivity from kubo's formula in Matlab.
2. Export conductivity over frequency into a *.tab file.
3. In HFSS, add a new material with frequency-dependent properties, then import the tab file of conductivity mentioned before.
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We have carried out H2 adsorption and desorption measurements at 77 and 273 K using a low-pressure (0-1 bar) gas sorption analyzer (i.e. volumetric method) for a pure few-layer graphene powder (FLG) and a Pt-doped FLG analogue with 1 wt.% dopant (Pt-FLG). It should be pointed out that the pure FLG has a higher BET specific area than the Pt-FLG sample.
Both samples exhibited fully reversible H2 sorption isotherms at 77 K (the H2 uptake for the pure FLG sample was higher at 1 bar), however for the case of Pt-FLG at 273 K we have observed that desorption does not follow the same pathway with adsorption (even though there is a slightly higher H2 uptake for the Pt-FLG at 1 bar) and a small hysteresis is observed. To be more precise, the desorption isotherm is present above the adsorption isotherm and forms that hysteresis.
I would presume that this may attributed to weak chemisorption phenomena (e.g. spillover effect), which leads to a slightly higher H2 uptake at 273 K for the Pt-FLG relative to the pure FLG, as well as to a not fully-reversible H2 desorption.
Thank you in advance for your consideration and please let me know your thoughts.
Best regards,
Nikos
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manly inn metals, such phenomena can be observed due to formation of hydrogen-induced vacancies. But I don't think it happen in carbon. Pt is known to be the high catalytic activities; the probability of Hcs formation is expected.
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Hello,
Following many procedures, I am spin coating a 1mg/ml GO in water suspension onto a nylon membrane, repeated 5 times (3000rpm, 30sec). However, there still seems to be defects, as the gas permeance of the membrane is much higher than previously reported. Any idea what the issue might be? Should I do some heat treatment to ensure proper adhesion? Dry the membrane in vac. oven between spin coating additional layers? Visually, the GO layer seems to be well stuck to the support ( no peeling).
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Maybe you should check your membrane by SEM to make sure that there is no defects in it. Besides, is the size of your membrane identical to that reported?
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Hello,
I am preparing GO using hummers method as follows:
Briefly, 69 mL of concentrated H2SO4 was slowly
added to a mixture of graphite powder (3 g, 1 wt equivalent) and
NaNO3 (1.5 g, 0.5 wt equivalent) in a 500 mL beaker. The mixture
was cooled down to 0 ◦C in an ice bath and stirred for 1 h. Then,
KMnO4 (9.0 g, 3 wt equivalent) was slowly added in portions to
keep the reaction temperature below 20 ◦C. The beaker was then
placed in a 35 ◦C water bath and the solution was stirred for ∼1 h
to form a thick paste to which ultra-pure DI water (138 mL) was
added slowly, which produced a large 98 ◦C exotherm; maintained
atthis temperature for 15 min. Then, a mixture of DI water (420 mL)
and 30% H2O2 (10 mL) were added, producing another exotherm at
below 20 ◦C. Finally, the solution was filtered to obtain the precipitate.
i followed these instructions very closely, especially maintaining the temp, i got the green color after adding kmno4 and brown after adding water, however i was unable to get the bright yellow color on adding hydrogen peroxide, instead i got a dirty greenish brown color (pic attached). I did see yellow bubbles on adding h202 but the color of the whole solution does not change to yellow.../
My questions what does the color change to yellow indicate? If I am not getting it which step could the mistake be in?
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Hi there
I had the same problem while synthesizing graphene oxide. I know this question has been asked several years ago, but I am about to share with my experience about preparing graphene oxide, I hope it works for all those researchers who face this challenge and see this page. The problem of your procedure is that you applied low temperature while adding H2O2. You must pour it when the temperature of mixture is high, around 45 to 98, depending on the application predicted to the GO product. Actually the logic behind adding water before adding H2O2 is to rise the temperature of mixture, but unfortunately you kept T below 20 degrees of centigrade. So the next time you need to put the mixture into a high T water bath if you want to get GO and brownish yellow color.
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Graphene has been a material of interest since its discovery in 2004 on account of its excellent physical properties. Can someone please explain the synthesis of Graphene by electrolysis?
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Graphite as anode, sulphates or sulphuric acid as electrolyte, approx 10-15 V D.C. (cathode -graphite, some metals:Ti, Pt, Fe alloys. ).
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I'm currently repeating literature experiments to chemically exfoliate graphite into graphene oxide, and two things that always pop up are the use of dimethylformamide and methanol. Does anyone know the purpose of these two chemicals in graphene oxide?
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I think this paper is very good
A Study of Stable Graphene Oxide Dispersions in Various Solvents.
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Graphene has even been termed as the “miracle material” and is often said to be the new silicon by many. Do we know where we are now on the Gartner hype curve? How far are we from the technology’s broad production, commercialization, and market applicability?
Thank you very much.
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Being somebody on the sideline, reading every once in a while about graphen research, feel as if I read about a similar history as I have experienced. I am active in conductive polymers since the early days of polyacetylene, and I have successfully developed a conductive polymer and technologies based on it which are successful in the market, and during all this time, I had lots of discussions in this research field, cf
As with graphene, conductive polymers had been declared to be "miracle materials" well before anybody had even scratched the surface of understanding these materials, not to talk about a real deep understanding of their chemistry, physics and technology.
Conductive polymers had been declared to be able to do anything you can name, light-weight batteries for cars, polymer LEDs for flat-screen TVs, actuators for robots, sensors for any task you could imagine ...
What has finally emerged as quite small and not too exciting application are transparent antistatic coating (Bayer's PEDOT based on a license granted by me) and my own technologies
- final finishing of printed circuit boards
(competitor's process not based on the Organic Metal Polyaniline)
- and corrosion protection
none of which had been predicted by anybody (including myself), and if so: it would not have excited anybody because "corrosion protection" or "printed circuit boards" (PCB) are not considered being "high-tech" (in spite of that PCBs are part of the core of any high-tech device).
My feeling is that graphene is also on the downhill part of the "hype curve", and I would not be surprised if such applications would finally arise which nobody has ever predicted.
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can we also identify Few layer graphene and multi layer graphine by seeing Intensity ratio values i.e. (ID/IG) 
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I think AFM is far better option then using Raman for distinguishing different layers of Graphene.
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Graphene ia a allotrope of carbon extremely conductive,strong and hard
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I used alfa aeser 13382 Copper foil, 0.025mm (0.001in) thick, annealed in CVD when growing graphene. But surface roughness is not enough smooth. some technique was used like chemically etching by nitric acid and etc. but i am not sure which one is best.
best regards
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This is how I did it with 100 micron Cu foil by recrystallizing top surface and used chemical hand polishing method to get very large area monolayer Gr.
1. Annealing 1050 / 1060 CAnnealing time = around 5 hr (Ramping up time = 30 min to 1 hr, Steady temp time = 5 hrs)Gas condition Ar:H2 :: 5:1
2. Chemical polishing:
  • Take Cu etchant with different dilutation. At least 4-5 dilutation of Cu etchant with water
  • High concentration Cu etchant will smooth up the Cu substrate, but it will oxidized the Cu substrate also
  • Rub with diluted Cu etchant to remove the majority of oxide
  • Rub with more diluted etchant to romve more oxide
  • Reapet these procesess untill all of the Oxide removes and Substrate looks clean and shiny
  • Rub with water at the end to remove CuCl3 from the substrate
After these you will get something like this attached image..Good luck..
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The examination has been conducted on GO suspension samples. The major problem came across to my mind is referred to possible damage on the apparatuses.
Thanks for your kind help.
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The anomalous steps in apparatus 2 are due to lamp/filter changes.
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Such that after centrifugation, it was quite difficult to see the impurities that settled.. what is the possible reason for the dark color??
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HI Elaine
because 1- increasing time  sonication
2-increasing acid and time
product  not graphene oxide
change of stracture product porous and capture gas 
product brown liquid .
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Hi,I am trying to make graphene based hydrogel via the hydrothermal route.I tried heating a 30mL, 1mg/ml graphene oxide(GO) solution in 50 ml autoclave for 12hrs.At the end i found only carbon soot left at the bottom.Also,I tried heating 30 ml, 2mg/ml GO  solution in 50ml autoclave for 3 hrs,but got a paste at the bottom with no mechanical strength.I do not understand what I am doing wrong.Please help.
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yes Mohammad Rehan Sir these factor may affect the gelation 
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I am simulating graphene nanoribbon. It is working when Transmission is a function of energy, but i want to calculate transmission as a function of different applied bias, I have done it for zero bias, when transmission is a function of both applied bias as well as energy then how to calculate transmission function. Please share your views if any idea.
Thanks in advance
regards
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Hi, The best method is to use Sancho algorithm. This method is well documented
for instance take look at :
The Non-Equilibrium Green’s Function Method  for Nanoscale Device Simulation
by Mahdi Pourfath
good luck with your research
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Most of the literature that I am going through use graphene flakes for liquid phase exfoliation, The Graphene flakes that sigma provide is with particle size +100 mesh (≥75% min) which is around 150 μm
(http://www.sigmaaldrich.com/catalog/product/aldrich/332461?lang=en&region=IN) while graphite powder is with particle size <20 μm ( http://www.sigmaaldrich.com/catalog/product/aldrich/282863?lang=en&region=IN). How does the particle size effect the graphene and which one is suitable for liquid phase exfoliation? My end use is for inkjet printing, so I have to take care of the nozzle clogging, the particl size should be less than 2 μm. Looking for valuable suggestions and advices. Thanks
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Thank you very much for the advice and suggestion, I will try it out and let you people know the result
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It's easy to build a perovskite structure (CaTiO3 unit cell) or a graphene sheet individually in VESTA. But I am interested to know if its possible to place a Graphene on any perovskite such as CaTiO3 in VESTA. I'm trying to build but the mismatch of the lattice constant distorts the overall structure. I am new in using VESTA so any help or suggestions from the experts is welcome. 
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I try to report all the steps:
- open your cif file with Vesta
- go to the edit menu>edit data>phase
- click import and then select you new file
- click apply
- Now you can edit the position and the orientation of each phase changing the respective layers 
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I found in a lot of papers showing 3 realizable peaks D,G and 2D. In some works, there usually is a significant small peak (next to the 2D peak, you can google with keyword Graphene Raman), which is mostly appriximate 2435 cm-1. I haven't read any information about it.
I did the raman tests several times but the strange peak is still at the same position. Could it be the new phase/mode of graphene?
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Hi Şenyıldız,
I believe it is the D+D". They have some arguments about it but I prefer this work:
May, P. et al. Signature of the two-dimensional phonon dispersion in graphene probed by double-resonant Raman scattering. Physical Review B 87, doi:10.1103/PhysRevB.87.075402 (2013). .
The band at approximately 2440 cm-1 is assigned to the contribution of a transverse optical phonon D and a longitudinal acoustic phonon D”, usually referred as D+D” or G* mode.
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Dear all
Is there a way that I could have time evolution of the number of water molecules between a given residue and graphene sheet?
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All we weighed, after a while the water has evaporated you weighed residue, etc.
This is a simple gravimetric method.
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I am trying to obtain transfer curve (Vg, gate voltage vs. Id, drain current) with graphene transistor using 2636A Keithley source-meter. Device basic structure is attached.
I have put drain voltage fixed as 30 mV and made the gate voltage sweep from -20 V to 20 V. When the gate voltage is negative, I am getting perfect curve as it should be theoretically. But when the gate voltage appears as positive, I am getting negative current. I have attached the curve I have obtained. Your kind suggesting is requested to come out from this predicament.    
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If the structure is large enough, you could call in the assistance of a theorist and ask them to construct a simulation based on my latest QED model, please see link to my latest paper on the subject for more details, if required:
Deleted research item The research item mentioned here has been deleted
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I want to prepare Graphene Nanoplatelets (GNP) solution in ethanol for a coating process. I want to achieve a well-dispersed GNP solution and I have GNP with me. I also want to make it in the least time possible. The best possible combination I found on surveying research papers was 0.05g GNP in 20 mL ethanol sonicated for 2 hours. However that is not very practical given the amount of GNP solution I require. Does anybody know of any other conc/time combination which can be achieved by ultrasonication. 
One advantage is I do not require dispersion for long amount of time: maximum stability for 3 days.
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To improve dispersion of  graphene,you can functionalize it  with hydrophilic group or add a sufficient surfactant
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Dear researchers, would anyone help me understanding how the spin of electrons could be affected on graphene layer if hBN is laid beneath that graphene layer?
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What would count as "affected" for you? In any case , Id be surprised if it was . 
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I am working on graphene based biosensor can someone help with any useful link or material. Any assistance would be much appreciated.
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Just go through this
1) Graphene-gated biochip for the detection of cardiac marker Troponin I 
2) One step in-situ synthesis of amine functionalized graphene for immunosensing of cardiac marker cTnI
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I work with striper foils from grapheme  for cyclotrons. The results are good and interesting. Right now I need to find producers of grapheme fooils with thickness 105 microns. I bought from Nanotech from Austin, TX, but I need to find supplier, which I can input to list of suppliers. It is not simple question.
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Please contact me Kaneka has such films
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I am preparing Graphene by using modified hummers method... I have little confusion with colour...
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You can't obtain graphene from modified Hummers method. Starting from natural graphite, by means of the modified Hummers method you can obtain, after exfoliation, graphene oxide (GO). GO can be reduced (thermically or chemically) in a product similar to graphene (but more defective) usually named as reduced-graphene oxide (rGO).
However, the color of graphene in powder or dispersed in a solvent is black. The same for rGO. The colour of GO, instead, depends from the oxidation and from the solvent in which it is dispersed. GO dispersed in water is brownish.
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what are the ways to create controlled defects in graphene? which one is the simplest that can be implemented in the lab?
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You can also produce defects by large fabrication of graphene, secondly by the irradiation of heavy ions to create vacancies.
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synthesis of GO
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Simply (guestion is too general), the longer time of oxidation you will apply, the more oxygen containing groups you will obtain (which is usually desired). GO with higher amount of oxygen groups is more polar (hydrophylic) and its "solution" is more stable and surface is more active (C/O ratio is one of important characteristic of GO). Not only oxidation time but ofcourse other conditions (temperature, pH, used oxidants, starting material, good timing) are very important too. And one thing is in my opinion more important than the others - exfoliation process. Even if you will make everything perfect except of exfoliation, you will never obtain material with full scale properties. So good oxidation process only is not guarantee of success in GO synthesis.
The oxidation proces of carbon can be generally understood in the very simplified way (increasing numbers of C-O bonds on one C atom from 1-4):
RC-C > RC-C-OH > RC-C(O)H > RC-C(O)OH > RC + CO2
Stable groups are taken into account only. The formation of epoxides is possible too (but is overestimated in my opinion). The best is the penultimate case (highest oxygen content, highest stability in water), the last one possibility which can happend under vigorous conditions (decarboxylation) is unvanted in greater extent.
Some works precisely examining the effects of oxidation - there exist many studies and more can be easily found than these two below.
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i want to find a graphene ball.
i mean, i make a graphene nanoball
but i have a difficult to find a this shape at the TEM
 when i make a TEM sampleing, i usually use a Etanol and sonication
but, during the process, the shape was collapse
so, TEM Image was just like sheet, not nanoball.
please help.
how can i anaysis the TEM to find a graphene microball sample
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I guess that the structure of G-nanoball is not stable, so let think about how to stabilizing this before processing TEM technique. If you can't, let try other technique like SEM (I'm not sure that the ball structure can be perfect visible by this technique but let try).
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In my experiment, I find that the transferred graphene on SiO2 wafer chip off from the wafer in aqueous solution and  organic solvents. As described in the title, I want to get an effective method to improve the interaction between transferred graphene and SiO2 wafer.
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In our experiments, O3-treated and Boiled in the solution of H2SO4/H2O2 would improve the hydrophily of SiO2 wafers, which  result in the imporvement of the interaction between graphene and wafer.
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i synthesized RGO from GO in different reduction techniques with NH2-NH2, NaBH4, NaOH, and some more from the attached review paper. in all these cases i am getting least 1-5 k ohm resistance, which is not suitable for the high conductive application. can anyone suggest to improve its conductance .
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You could try with N-doped rGO, has more conductivity than rGO.
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1- Cutting graphene on Cu foil ?
2- Cutting  PMMA coated graphene on Cu foil ?
3- Cutting graphene after transfer on substrate? 
Which technique can be true for this question and what can be the drawbacks of these situations?
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Cutting the graphene/Cu foil with clean scissors have generally worked fine for me, where I generally grow graphene on a large copper foil, and then cut into smaller 1X1 cm using a scissor (cleaned with Acetone). The conductivity seems to be the same over all my pieces.
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going to print the super capacitor using graphene ink in screen printing,help me out for the design , super capacitor in series
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DOI: 10.1002/aenm.201300184
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Would it be possible to fabricate the 3d graphene, for instance, graphene sponge by plasma or cvd rather than reduction of GO by hydrothermal? how to design such experiments? thank you very much
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Pretty simple.. if by CVD use some 3D structured catalyst like Nickel foam.. if you have GO, freeze drying.. dozens of papers on this topic
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I needed to model a graphene layer on top of any solid blocks and want to analyze the properties of graphene? Pleases suggest me any simulation tools. It can be done in comsol: if then how to proceed in it. Please guide me step by step.
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Santhosh,
You can do this simulation using ANSYS ans ABAQUS as well.
In ANSYS, you can assign diffrent properties to the layers you designed by creating two materials models while imputting material properties and select diffrent mesh attributes for diffrent layers before meshing.
Hope this helps.
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This is to have an insight on plating/ coating of graphene on a metal, plastic or a substrate, its viability, in order to increase its application into different verticals like automotive, energy, manufacturing etc. 
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The basic question to electroplate by  a material is  to have it  in  the liquid state ( in solution, I mean). Is it possible to dissolve graphene ? No, so the alternate is to use graphene oxide ( GO ) with supporting electrolyte , once done transform the GO to graphene , an easy but nevertheless a difficult task to keep uniform surface but worth trying
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Graphene oxide is easily dispersed in water through ultrasonic processing and their aqueous dispersion is stable. However, this graphene oxide suspension begin to agglomerate with addition of magnesium chloride.
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[1] Although pH did not have a notable influence on GO stability from pH 4 to 10,  ionic compounds have significant effect on GO stability due to electrical double layer compression, similar to other colloidal particles.
[2]The critical coagulation concentration (CCC) values of GO were determined to be 44 mM NaCl, 0.9 mM CaCl2, and 1.3 mM MgCl2.,i.e. follow DLVO and Schulze-Hardy rule .
[3] Mg^2  binds with  with the oppositely charged hydroxyl and carbonyl  groups of GO and destabilize[ by neutralization] it so that GO particles  start coagulating/ flocculating   [ analogous to aggolomerization]
 REFERENCE:
Environ Sci Technol. 2013 Jun 18;47(12):6288-96. doi: 10.1021/es400483k. Epub 2013 May 28.
Colloidal properties and stability of graphene oxide nanomaterials in the aquatic environment.
Chowdhury I1, Duch MC, Mansukhani ND, Hersam MC, Bouchard D
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Use of prepeg reinforced with carbon nanotubes and graphene in naval industry such as hull construction
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What benefit would you be expecting from the use of such expensive and hard to process additives ?  So far there have been no real benefits to mechanical performance of  such modified resin matrices, all measurable effects have been associated with electrical /thermal conductivity enhancement. 
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I have read many papers reporting the synthesis of single-crystal graphene or pervoskite material. However, I have not gained a clear insight into how can we confirm the single-crystal phase? I will appreciate if who can give me some hint.
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Dear Xu,
This is very much depending on how pristine your samples is. If your sample is 2-3 layers you can pretty much assured it is of a single crystal in nature. So first, you need to determine the type of graphene (layers) you are producing.
Generally we use HRTEM image to measure the lattice spacing to determine if the structure is really single crystal in nature. The lesser the number of layers the easier for you to determine. If the sample is say 5-10 layers, we usually sample more locations within the same specimen and repeat it with several specimens to get a good statistical data. This is done as confirmation even if the SAED shows definite bright spots. This can be a really tedious job in the beginning. 
You can even use scanning tunneling microscope but again the number of sample/location has to be statistically sound.
For metals usually we use XRD to do a wide scan. XRD scans a larger area and would give us a quick response on the crystal structure. However, I'm not so sure if this really possible with pristine graphene with <5 layers.
Usually samples are polycrystals  made of large qty of single crystals with dislocations, faults, etc. So I think it is a bit difficult to expect a pure single crystal graphene phase at the level that you are working on. It may be possible with quantum dots based on my experience.
Not sure if this really addressed your problem but hope it helps.
Rgds
Dr Shutesh
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Which is an easy and simple method to synthesize graphene quantum dots in lab?
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Hi dear
In a typical procedure of GQDs preparation, 2 g Citric acid was put into a 5 mL beaker and heated to 200 C using a heating mantle. About 5min later, the CA was liquated. Subsequently, the color of the liquid was changed from colorless to pale yellow,
and then orange in 30 min, implying the formation of GQDs. The obtained orange liquid for preparing GQDs was added drop by drop into 100 mL of 10 mg mL1 NaOH solution,
under vigorous stirring. After neutralized to pH 7.0 with NaOH, the aqueous solution of GQDs was obtained.
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Actually I have almost everything for the experiment - chemicals, foil, CVD equipment and so on. And here is the thing - how to adjust the flow of gases?
Here you can see a part of a receipt from an article "The copper foil deposition substrate was loaded into a furnace and heated to 1,000 °C in an argon/hydrogen reducing environment to remove any native oxide on the surface of the copper. A small flow of methane was added to the gas flow."
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You have to start with copper and silicon wafer substrates. You can use copper foil (25-50 μm-thick Cu foils). However, before using the foil make it annealed to a high temperature to remove the oxcide content (in case present).
You have to use three diffrent gases Ar, H2, CH4 by using three gas cylinders. You can adjust the gas flow rate by a mass flow controler (MFC).
If you do not have Annealing system (for Cu foil) you can also follow the below procedure:
1. Hydrogen gas (say 40 sccm flow rate) can be discharged by an RF power of 50-100 W for 2-3 minutes to eliminate surface oxides on the copper foil.
2. After that purge with Ar at the flow rate of 100 sccm for 2-3 minutes to remove residual hydrogen gas.
3. Then you have either you can select Ar + CH4 or H2 + CH4
Put pressure (operating condition for your graphine film) = 10 mTorr. For this inject 1 sccm of CH4. and then add Ar or H2 to achieve 10 mTorr.
4. Vary your RF power from 50-200 W and grow your film.
After trying with Ar + CH4 or H2 + CH4  combinations you can go for Ar + CH4 +H2 gases.
Good luck.
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I study the mechanical properties for polyurethane (TPUs) with graphite nanoplatelets (GNP) nanofillers . I have seen that for annealing samples the mechanical properties increase for pristine one due to phase separation between the hard segment and soft segment, but decrease for TPU nanocomposites?
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If possible, please try to compare the morphology of the nanocomposite samples before and after annealing. There can be several reasons for the different behavior. If e.g. the nanoparticles tend to agglomerate after annealing, the material becomes from nanocomposite to a microcomposite - with worse mechanical properties.
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Looking for a direct quantification method that evaluates the difference primarily reflected due to the carbon coordination. If any relevant literature is available please share. Thanks in advance.
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Apart from directly visualizing the structure using  STM, XPS can be a powerful tool as an alternative. Depending upon vacancies and non-conjugated carbon, the line shape of C1s spectrum broadens.  A careful analysis will help to quantify these defects.
Kindly go thru the following articles...
1. Electronic and mechanical degradation of oxidized CNTs doi:10.1016/j.carbon.2011.12.009
2. Initial Stages of Oxidation on Graphitic Surfaces: Photoemission Study and Density Functional Theory Calculations; DOI: 10.1021/jp902051d
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what is the difference between graphene nanosheets , graphene nanplatelets and graphene nanopowder
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Dear Farhan,....
that's a very good question. In principle there is always the need to get clear characterizations and definitions of new material modifications. In the case of carbon materials there is an institution in Germany, the AKK (Arbeitskreis Kohlenstoff) within the DKG (Deutsche keramische Gesellschaft) and the EAC (European Carbon Assoziation). This working group was founded in the 60ies and is an independent association for scientific and technical exchange. They have two meetings each year, including a technical commitee meeting, which are providing advice about terms for new carbon materials or nanomaterials. The publish the actual results in:
 „Terminologie zur Beschreibung von Kohlenstoff als Feststoff“ (ISBN print version: 978-3-89958-770-8; Onlineversion: 978-3-89958-771-5).
With best regards
Michael
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Is truly necessary to the operation of the rGO-CeO2 nanocomposite as photo-emitter or photo-catalyst that rGO is of good quality? Could similar results be obtained directly using GO? What will the possible difference between the results?
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Yes, rGO should be of good quality. Otherwise, low photocatalytic activity will be observed as a result of low mobility and/or quick recombination of photoproduced charge carriers. rGO is mostly better than GO.
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Graphene has negative thermal expansion coefficient (TEC) i.e. it increases when temperature decreases unlike all metals which show positive TEC. Why does graphene and metal/insulators like SiC or Si have difference in the sign of  thermal expansion coefficient (TEC)?
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One might also note the in-plane CTE of high quality graphite and its temperature dependence.  
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Hello researchers, I need your help.
I am currently trying to conjugate a murine antibody and Graphene Oxide. 
The reaction will be conducted under EDC coupling, which uses the amine group of lysein on the antibody and carboxylic acid groups on GO.
I am confused on how much antibody per mg of GO I should use. 
Also after conjugation, other than FT-IR analysis, what could be a good determinant method for yield of conjugation.
Please share your thoughts and knowledge. Thank you
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GO interaction with antibody can be seen also from the XRD pattern. Is there any shift in the XRD peak of GO? Moreover, if amide linkages are formed then one can easily see the functional groups in the FTIR spectra or by ATR. Thermal analysis data will also give you indication of the bonding between GO and antibody.
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Does any one know the sheet resistance of graphene in ohm-cm^2 ?
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30 ohm/sq for single layer
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I want to know more about the surface of nanocomposites, especially graphene-based nanocomposite and my major field is nanochemistry.
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Thank you very much @Phebe
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I'm doing the retention test with Galvano. The material is Graphene/PANI.
By considering graphene is in the sample the galvano should be continue till the end (1000 cycle) even though retention is not very good.
My  problem here is, they do not go until 1000 cycle (Refer to the attached photo plz). Could you please help me out with the possible answer?
Ag/AgCl Electrod
Electrolyte - H2SO4
I       (-1mA~1mA)
T1     (100~10)
EM     (-0.2V~0.8V)
E Range (-1V;1V)
I Range 10mA
Thank you in advance.
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@Soojeong >> Thanks for your answer.
Do you think i did wrong in the method of in-situ polymerization ? Or the fabrication method for the electrode? (I mix all of the Graphene/PANI+Carbon black+PTFE by simple mixing method) 
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 Some groups have been reported after annealing graphene on SiO2/Si substrate, the value of  I(2D)/I(G) decreases. So on the basis of intensity ratio of Raman peaks, after annealing, we can not say graphene is mono layer or bi-layer.
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It is difficult to confirm graphene (monolayer) or bilayer graphene with Raman analysis. I(2D)/I(G) ratio of graphene, which has been used as criterion of graphene, largely ranges between ~1 and 4.5 (L. Tao et. al., Uniform wafer-scale chemical vapor deposition of graphene..., The Journal of Physical Chemistry C (2012) 24068). This indicates that Raman cannot provide conclusive evidence of graphene. Also we have to know that different Raman signals can be obtained even from a SAME position of a sample.
AFM reveals an angstrom thick step, rather than graphene. The signals of SAED patterns can be changed with tilts of the sample, and thus cannot provide direct evidence of graphene.
HRTEM images (for sheet typed graphene) and XRD patterns (for powder typed graphene) can be DIRECT (Physical) evidence of the presence graphene. Please see Lee et. al.’s paper, The seeded growth of graphene, Scientific Reports, 2014. Graphene nano-sheets and graphene nano-powders are clearly and simply demonstrated by conventional HRTEM (working at 200 kV) images and unique XRD patterns, respectively.
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I have tio2/graphene nanocomposite XRD spectra and want to see graphene peak position.
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The XRD peak at 26.6 deg demonstrates that the sigma graphene sample is of graphite where quality can be confirmed by Raman. I know that such unphysical problem is not only yours, but prevails in the studies of graphene. The samples are practically graphite.
I understand that scientific papers must be based on facts.
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Dear All
please, Why P25/GO has a bad dispersion in pollutant than P25. I used both of them for MB removal and i found that P25/GO is not dispersed well in MB, but i just put P25 in MB, it is dispersed well and the removal efficiency of P25 is higher than P25/GO
Regards,
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 As Dr. Sarkar mentioned, you need to use reduced Graphene Oxide (rGO) if you are looking for ameliorating the catalytic efficiency. That way, the efficiency might increase which can be attributed to any/both of the following factors:
1. These might be degradation of dye due to surface adsorption on the rGO sheets.
2. rGO might act as macromolecular photosensitizer and inject electrons into conduction band of TiO2. This way it uses the photons efficiently.
Hope this is helpful.
Many thanks.
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Dear All
I prepared P25/GO 0.1 % ratio. When filtrating the solution to get the solid P25/GO 0.1 %, I found that the filterate is white as the titania pass through the filter paper. This is completely different from P25/GO 5 % ratio (the filterate is clear with no titania). Is this normal for preparation of small ratios.? I think this is not fair when comparing P25 with P25/GO 1 % ratio because a large amount of titania was not bound with GO.
I am look forward to helping me to understand this issue
Regards,
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You could prepare a GO dispersion and by dryness you know the GO concentration. To that concentration determined GO dispersion add the % in mass of p25. The dispersion will precipitate and by centrifugtion you get a p25 -GO at disired concentration.
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I measured BET of few layered graphene.But, it is giving very low specific area around 8-10 m2/g only. Before BET measurement is there any process required for materials..?
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The sample should be dried completely so that no water molecule should present in between the layers.
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If there any method to find the dielectric constant and permeability of graphene in GHz? I want to use it in an antenna. I find a lot of paper to consider the value of dielectric constant of graphene, but a lot of paper didn't showed the appropriate value of graphene.
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Dear Shen-Ming Chen  and Hamza Kaouach,
Thank you very much for all of your answer .
Dear Anvesh Kumar Nella,
Why the dielectric constant and permeability are not in GHz? I really don't know about it.
Thank you very much to everyone.
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It is difficult to weigh the pellet if I start with the low scale GO. 
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UV-Vis can be used to estimate the concentration.  The maximum absorption (Abs) at around 230 nm.  cGO in mg/mL = Abs/0.47*0.01
To accurately determine the concentration, freeze drying or drying the supernatant in oven at 60-70 oC would be better. 
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I have graphene already grown on Ni metal. I want to dope graphene with Al or Al-like atoms in order to enhance the sensing property of graphene.
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You could use hydrothermal technique to dope graphene by using precursor of requested atom. It would be worth trying it.
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I have prepared graphene hydrogel from aqueous dispersion with ascorbate acid.
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 "Facile sonochemical synthesis and electrochemical investigation of ceria/graphene nanocomposites." Journal of Materials Chemistry B 3.11 (2015): 2362-2370.
DOI: 10.1039/C4TB01847H
or here
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while changing the condition I am getting FLG. But the literature says graphene growth is self limited so what is the reason for forming FLG on SLG on copper foil.
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You may find your answer in our paper:
Controlled growth of large area multilayer graphene on copper by chemical vapour deposition, Physical Chemistry Chemical Physics 17(35) · July 2015.
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Scientific drawing software. What kind of software is used for the same?
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Inkscape for 2D and Blender for 3D pictures.
Blender for animations
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Dear All
I used TiO2/GO 5% wt composite to degrade carbofuran at UV 350 nm and the activity of P25 was better than P25/GO 5% wt composite Also I used in visible range and there is no any activity of P25/GO. I do not know what is the reason that GO suppress P25 activity.
Regards,
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I think that PhCat activity of TiO2/GO composites is strongly dependent on quality of GO. 
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I want  user friendly codes or packages for tight binding calcualtiuons of graphene like materials
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Thanks for all of you, for your kind suggestions
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How can I prove the intercalation of molecules between the graphene sheet?Theory and explanation?
I mean, many papers have reported the synthesis G from exfoliation, and others have also studied about the intercalation of molecules (metal/metal oxide, polymer, etc). What's the difference between the exfoliation from intercalation vs only intercalation (for somewhat purpose)? Furthermore, the gap between G sheet is very small and I cannot imagine the intercalation of big molecule to small gap, and how to control the adsoption/intercalation? Temperature, stirring speed, pH, solvent, condition phase, or what?
Thanks
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First of all, the intercalation into the graphene layer could be proved by X-ray diffraction studies where the layers are exfoliated due to intercalation, as a result, the spacing between layers got increased. XRD peak will shift towards lower 2 theta.
Typical van der Wall separation of graphene layers is 0.335 nm. The extent of intercalation depends on the above parameters you have mentioned, including potential.
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As you know graphene quantum dots have luminescent properties. I'm looking for an applicable method which yields graphene QD with emission in IR or NIR  region!
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Dear Mana Farivar & Shantilal Mehetre i have attached a pdf, i hope it helps.
with regards Dhanu Chettri.
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I am trying to synthesize GQDs by a practical way but the prevalent methods contribute to blue or green absorption. I need a process to have Near IR.
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Dear Pegah Bagheri, do check the pdf file i have attached
also you can find more in the articles 
Three Colors Emission from S,N Co-doped Graphene Quantum Dots for Visible Light H2 Production and Bioimaging. DOI: 10.1002/adom.201400549
N, S co-doped graphene quantum dots from a single source precursor used for photodynamic cancer therapy under two-photon excitation. DOI: 10.1039/b000000x
minFluorescence Carbon Nanoparticles Derived from Natural Material of Mango Fruit for Bio-imaging Probes. DOI: 10.1039/C4NR04805A
Quantum-Sized Carbon Dots for Bright and Colorful Photoluminescence. DOI:10.1021/ja062677d
I hope it helps. 
With regards Dhanu Chettri.
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In graphene transfer to polymeric substrate. How does the substrate surface affect the transfer ability?
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The surface roughness of the substrate is crucial for the transfer-ability of graphene. The flatter the substrate, the stronger are the van der Waals forces keeping it attached to the substrate. Graphene on SiO2, for example, is easily peeled-off in contact with a Boron nitride (hBN) substrate. 
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As graphane is used almost every where to make composite materials, what is the best way to ensure the quality of it?
XRD?
RAMAN?
Electrical conductivity?
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The best way to ensure the quality of graphene depends on its applications, i.e. where will you use that graphene. If you want to use in electronics, then definitely electrical conductivity would be a prime choice. But for composite with graphene, Raman is the best way to judge the graphene quality. As it is known that Raman spectroscopy is the best characterization method for carbon materials where D band (defect band) and G band (graphitic band) ensure the quality of graphene from the their intensities. Moreover, being a spectroscopy technique, it is fast and provides the probable interactions within the composite also.
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I have prepared graphene quantum dots but they are dissoving in water.
Is GQD soluble in water irrespective of the method we use to prepare them? or the solubility depends on preparation method. Kindly answer me if any one is familliar with GQD.
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GQD is not soluble. It is only extremely small graphene sheet in size., which is difficultly observed with our eyes. Usually, GQD is exists in faint yellow solution form due to its easy aggregation.
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Dear All,
I am trying to fabricate graphene with high conductivity and also of large size (Micrometer) on SiO2 surface. Can you please suggest me the best way of doing so?
Thanks in advance
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I guess below mentioned paper can be helpful for you to synthesis large scale graphene flakes with high conductivity.
 "Solid-state functionalization of graphene with amino acids toward water-dispersity: implications on a composite with polyaniline and its characteristics as a supercapacitor electrode material"
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Which type of graphite did you use?
I've done experiment with method on this paper.
I was using graphite foil instead of flake type graphite on conductive carbon tape.
When I've done with flake on carbon tape. It didn't even have a current, that would mean that resistance was too big.
Can anyone give some advice for it?
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Hi Jang,
For graphene preparation by electrochemical method, graphite flakes, foil and rod can be used for the exfoliation. Exfoliation with graphite foil and rod is much easier to handle. But with the flakes, it's a bit tricky. You need to use big graphite flakes (particle size +100 mesh). Make sure the flakes are tightly adhered on the carbon tape. I am not sure what type of carbon tape you used or if there was any problem with connecting the tape with electrical wires. Nevertheless, it's better to use double sided tape. In the paper you mentioned, the carbon tape used for the exfoliation experiments are the small round shaped tapes that's normally used in the SEM measurements to fix the sample in the holder.  
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I have deposited iron oxide (4-10nm) on the graphene surface, but only D and G band of graphene can be detected, while iron oxide peaks can't observe in range 200-1000cm-1.
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Hi Zainul , you can use the infrared reflection techniques.
I'm sure by measurement of reflection at normal incidence, you could detectar some band FeyOx,  but ellipsometry technique is more sensitive to layer veri thin and  you can detect  FeyOx.
Even with the data that you get, you can determine a model to calculate the thickness.
regards...
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I want to use AFM to compare the surface roughness of Cu under different pretreatment process. But the Cu surface is waviness, whcich domainates the AFM results. Does anyone know how to obtain the results of the picture below?(Picture comes from "Effects of annealing on copper substrate surface morphology and graphene growth by chemical vapor deposition")
Thanks a lot.
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CMP
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I doubt on the leakage of chamber. how to make sure that the pressure of the chamber is good enought?
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I can't design your experiment for you; however, I have added a citation below that will give you a good place to start. 
Li, X., Cai, W., An, J., Kim, S., Nah, J., Yang, D., ... & Ruoff, R. S. (2009). Large-area synthesis of high-quality and uniform graphene films on copper foils. Science, 324(5932), 1312-1314.
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Waiting for your answer.Thanks!
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There has been an extensive discussion on this issue among RG members. Take a close look.
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I have Fe3O4@TiO2 on the surface of graphene. I am going to check the catalytic activity of this catalyst. what type of organic reaction do you suggest which match good with this catalytic system? I look for a transformation that is simple, green and doesn't need any expensive starting materials.
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Considering your reaction conditions, synthesis of bis-indolyl methanes, bis-pyrazoles, bis-coumarins, xanthenes or quinoxalines derivatives are suggested. All of above products are prepared fast and simple via cheap starting materials and Lewis acid catalysts.
With the best wishes