When I applied the same characterization condition and same weight of graphitic materials, graphene (red line) and graphite source (black line) got different intensities but the similar peak positions.
We conclude that the graphitic lattice of graphite had changed its periodic arrangement in the z-direction after exfoliation into graphite flakes.
Is that true and is there any formula for layers number and peak intensity?
Dear Minh
I think the peak intensity increase when number of layers increase, where the thickness (number of layers) for the material act important role in xrd characterization. you can note Bragg s law, where the reflection angle 2 theta of the beam was determined from the spacing between the layers and the number of peaks and their intensity depend mostly on crystal structure and other parameters.
I hope i help you, with my regards
Red line cannot be graphene, since the peak at 26 º indicates that you have ABAB stacking. Graphene is (by definition) a single layer of graphite, so there should be no stacking. Your peak says the opposite.
What do you mean z direction? We cannot guess what you mean if you don't show what z means in a figure. Anyway, since the peak at 26º remains in the same position, you did not change the interlayer distance.
You can estimate how many graphene you have by using the Scherrer equation to the FWHM of that peak (002) at 26º.
Graphene mentioned here is few-layer graphite. My point is why the intensity decreased while the peak position remained the same. Does it relate to the reduction of layer number of graphite? The z-direction is perpendicular to the basal plane (x,y) of graphene in graphitic structure.
No, it does not relate. Only the FWHM of the (002) peak at 26º is related to the number of layers of graphite. Your PEEG material (red curve) has a sharp (002) peak, so I would expect to have quite a lot of layer (very far from the graphene case).
In any case, graphene should show the peaks at ~43º corresponding to (10) reflections.
This is virtually the same suggestion we gave you in your previous question here: https://www.researchgate.net/post/How_to_determine_the_number_of_layers_of_graphene_nanopowder
Could you show me the formula about the relationship of FWHM (002) and number of layers of graphite?
Above, I already said the 'Scherrer equation':
http://bfy.tw/90Bi
http://bfy.tw/90Bi
Dear Minh,
You can also calculate the R parameter. It has been demonstrated in the literature that R can be used as a measure of the number of carbon sheets arranged as single layer. It decreases as the single-layer content of the carbon increases, such that when R = 1, all graphene layers are randomly distributed as single layers while larger (>1) values of R indicate a higher percentage of graphene sheets stacked in parallel. For further details please go to the: Liu et al., Carbon 1996, 34, 193–200 or Q. Deyang, Carbon, 2007, 45, 1296–1301.
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