HRTEM technique can show the layers but for scalable amount of graphene powder, I believe it's not an effective way. Another method, using XRD analyzing samples with similar examined amount (quantity), by comparing the intensity of the same peak location, we can calculate the number of layers. Is this true and what equation is it?
Are there any technique apart from Raman and XPS?
You should do it by XRD, but not with the peaks heights:
The number and separation of layers is related to the (002) peak of graphite (around 24 2theta degree if using CuKalpha radiation).
First, you calculate the interlayer separation from the position of the (002) peak using Bragg's law.
Second, you calculate the crystallite size using the width of the (002) peak in the Scherrer's formula.
Finally, dividing the crystal size (Scherrer), in the layer separation (Bragg) you obtain the average number of graphene layers.
You should do it by XRD, but not with the peaks heights:
The number and separation of layers is related to the (002) peak of graphite (around 24 2theta degree if using CuKalpha radiation).
First, you calculate the interlayer separation from the position of the (002) peak using Bragg's law.
Second, you calculate the crystallite size using the width of the (002) peak in the Scherrer's formula.
Finally, dividing the crystal size (Scherrer), in the layer separation (Bragg) you obtain the average number of graphene layers.
XRD is not a suitable technique for checking the number of graphene layers.
You should perfom a statistical analysis by AFM.
Hi Emanuele,
There is no fundamental reason why a few layers of graphene cannot be observed in XRD. The number of graphene layer can indeed be easily determined by the broad (002) XRD peak (if more than one layer, of course). Literature on 'few layer graphene' and XRD is vast:
Determination of non-uniform graphene thickness on SiC (0 0 0 1) by X-ray diffraction [Applied Surface Science 282 (2013) 297–301 ]
Few-layer graphene under high pressure: Raman and X-ray diffraction studies [Solid State Communications Volume 154, January 2013, Pages 15–18]
Feel free to remove the downvote!
Regards
Hi Dr. Vallejos-Burgos,
If the width of two samples are likely the same (similar crystallite size), by comparing the intensity of graphite source and the resulted graphene, could we determine the difference in number of layers? I mean if the heigh of the graphene peak is 1/3 smaller than graphite one (at same location 2theta=27 degree), respectively the number of graphene layers is 1/3 smaller than the graphite one. Is that correct?
May be he is asking you to check the FWHM of the scanned data. Therefore though the peaks are at the same 2Theta angle your Full Width Half Maxima (FWHM) will be different. From that the crystallite size can be determined.
Dear Minh Nhat Dang,
I know this question is one year old, but it was brought to life by Ali.
As Tanmay said, You cannot do what you asked me: the height of the peak DOES NOT DETERMINE the size of the crystal.
I told you how to do it in my first question: with the FWHM, not with the height.
Raman spectroscopy is the perfect method for determination of graphene layers.Also XRD can given an approximated results.
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