For my perovskite material I have got this XRD pattern (see the attachment). The baseline subtraction has already been done but still the prominent peaks are not arising from the baseline. I want to calculate crystalline size but I am not sure which peaks I should be taking into account. I try to calculate crystalline size from every peak and got vary large variations. Even if I exclude broader peaks, I get 5-10nm difference in D between prominent peaks. So please guide me in choosing in the peak(s) which must give accurate value of crystalline size D and microstrain.
Sushrut Mane To calculate the crystalline size D and microstrain for your perovskite material, you should focus on the most intense and sharp peaks in the XRD pattern. In this case, it would be beneficial to consider the peak near 25–28 degrees 2 theta as it is prominent and sharp. The peaks provide the most reliable information for size determination. Avoid broader peaks as they can lead to inaccuracies in size calculations.
Dear Sir Sushrut Mane
To find the crystallite size of a sample we need to know full width at half maxima (FWHM), wavelength of the X-ray.
Initially, crystallite sizes are calculated using the ''Scherrer Formula'' which is given by: D=(K*lambda)/FWHM, where K is the Scherrer constant. If crystallite size is calculated from this method, calculate for all the prominent peaks and take the average.
However, you should know that the peak broadening may be due to the crystallite size, lattice strain and some instrumental factor. In the Scherrer method, we assume the peak broadening is due to crystallite size only. Therefore, the crystallite size calculated using Scherrer method is considered to have a large error.
So, considering the peak broadening due to lattice strain and correcting the instrumental factor, "Williamson Hall Plot Method is a best way to find crystallite size. Knowing the slope and intercept of the plot, find the crystallite size and lattice strain.
First find the FWHM value of the high intense peak, then calculate the crystallite size.
Sushru
We can easily calculate the size of particles from Scherrer formula given: Scherrer Formula: Dp = (0.94 Χ λ) / (β Χ Cosθ) Where, Dp = Average Crystallite size, β = Line broadening in radians, θ = Bragg angle, λ = X-Ray wavelength. In your case according to my point of view you can select the peak at 26 the more heighted one.
Ayaz Mahsud , I too thought about selecting peak at 26 deg and using Scherrer formula but that peak had broad base and importantly elevated from baseline. Also, it has other peaks very close to it.
I found in one recent article, which has the same material as mine, that the author has used peak at 30 deg, mainly because of its sharp nature and distinct from other peaks.
So, I have decided to do the calculations with peak at 30 deg for rest of my doping samples also.
Thanks Ayaz Mahsud , B. Srikanth Ragunath , Haobam Samananda Singh and Alvena Shahid for your kind response.
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