Hi Danny, directly speaking the peak intensity can not serve as measure of the crystallinity in any case. Explicitly only peak FWHM can be used for the determination of crystallite size (but not materials crystallinity). The 002 peak of the graphite is a measure of interplanar spacing for two neighbouring graphene layers and its low intensity (compared to the commercial graphites) might be on the first glance associated to the positional disorder (and enhanced Debye-Waller factors). However without seeing data and their comparison it is hard to judge.

Yes intensity of peak is differed due to miller indices, Its intensity will be directly proportional to the number of diffracting electron densities in that indices. It will be changed only when there is a change in phase

Please refer the attached figure.

Peak maximum (or peak height), denoted as Imax, is fairly self explanatory, however it should not be used as a measure of diffracted intensity.

Peak area is indicated (in yellow) which is generally taken to be synonymous with "peak intensity” - regardless of the peak shape. (Source: http://pd.chem.ucl.ac.uk/pdnn/peaks/peakcon.htm )

Sharper XRD peaks are typically indicative of larger crystallite materials. Refer: XRD-crystallinity index and morphology index (https://www.researchgate.net/publication/233981900_Konjac_Bio-Molecules_Assisted_Rod-Spherical_shaped_Lead_Nano_PowderSynthesized_by_Electrolytic_Process_and_Its_Characterization_Studies?ev=prf_pub )

Sharper peaks = smaller peak area = smaller peak intensity = larger crystallite size

Peak broaden = larger peak area = larger peak intensity = small crystallite size

Article Konjac Bio-Molecules Assisted, Rod-Spherical shaped Lead Nan...

XRD is a well-known non-destructive analytical technique to determine the crystal structure. In particular, powder XRD becomes effective when large single crystals are difficult to obtain. XRD data gives information about samples in terms of peak position and intensity. The peak position is indicative of crystal structure and symmetry of contributing phase. The peak intensity reflects the total scattering from each crystal planes, and depends on the distribution of atoms in the crystal structure. In other words, intensity is related to both the crystal structure and composition. Relation between the atomic positions and the intensity of Bragg reflections can be established by considering the X-ray scattering by an electron, then by an atom, and finally by all the atoms in the unit cell. The intensity of diffracted beam in a particular direction is proportional to the modulus of square of geometrical structure factor (Fhkl), which depends on the occupancy of atoms in different Wyckoff positions of a unit cell and then, crystal. Since thermal vibration of atoms in the lattice point has influence on intensity of diffracted beam, a term that describes the thermal vibration of atoms should be included in the atomic scattering factor (fa). Apart from the structure and temperature factors, several others influence the intensity of the scattered beam in the case of a polycrystalline sample: polarization, multiplicity factor, Lorentz factor and absorption factor. In conclusion, intensity depends on both crystalline nature as well as occupancy of individual Wyckoff position in a crystal. If crystalline nature increases, number of planes orientated in a particular direction increases and hence multiplicity increases which lead to increase in intensity. Similarly, if all the Wyckoff positions in a crystal are occupied by the required number of atoms, then the structure factor gives high value, which will lead to high intensity. Apart from these things, sample preparation for XRD is also an important factor for intensity.

Hi Danny, directly speaking the peak intensity can not serve as measure of the crystallinity in any case. Explicitly only peak FWHM can be used for the determination of crystallite size (but not materials crystallinity). The 002 peak of the graphite is a measure of interplanar spacing for two neighbouring graphene layers and its low intensity (compared to the commercial graphites) might be on the first glance associated to the positional disorder (and enhanced Debye-Waller factors). However without seeing data and their comparison it is hard to judge.

Yes it has direct proportion to the peaks intensity. As the diffraction is due to the electron and according to the braggs law to the crystalline plates in a certain 2theta, the more intensity is equal to the more crystalline plates grown in a certain 2 theta. So, if the XRD background is smooth, and the peaks have a good separation, the more intensity is equal to the more crystalline plates grown in a certain 2 theta and you have a good crystalline material

Hello Danny,

did you try capillary measurements (Debye-Scherrer geometry)? Not every machine has the required sample stages, but moving away from Bragg-Brentano or transmission geometry will in most cases also reduce the effects of preferred orientation (given that your intensity problem really is caused by preferred orientation). The question might seem odd, but did you rotate your samples during measurements? This is usually the first thing to do if you suspect an effect of preferred orientation in your samples.

Also, the anisotropic shape of your crystals (needles instead of spheres like in the commercial sample) may have an effect on the peak intensity. For small crystallite sizes (nm range) anisotropic crystallite shape may lead to uneven peak broadening between the reflexes depending on the preferred growth direction of the crystallites. Do you have an idea on how big your graphite crystallites are?

Hope this helps, yet, without having a look on the data, these are only guesses.

Cheers,

Chris

I think this article might be helpful for you. It pretty much agree with Anatoliy Senyshyn's statement.

http://www.sciencedirect.com/science/article/pii/S0008622307001467

Let me know if you need a copy.