I have synthesized titanium dioxide thin films by ultrasonic spray a 400 °C with a different solution precursor, the prepared films annealing at 600°C.XRD results show that the crystalline size increase after annealing for lower concentration however, for a high concentration of precursor, the crystalline size diminish after annealing.
Why does crystalline size decrease after annealing ??
Dear Okba Ben Khetta
I suppose your experiments were carried out in razing angle setup.
The increased crystalline size with annealing corresponds to the expected behavior for a regular diffraction of such oxide.
Nevertheless, increasing the deposited amount by ultrasonic deposition may generate local saturation on the film deposition surface.
At drying by thermal treatment, a set of phenomena may occur. The expulsion of trapped solvent, interstitial substitution elimination, stoichiometry break-inducing phase segregation (it could be amorphous) are possibilities, and therefore a direct cell parameters interference on the desirable phase.
In the literature, you find examples of cell shrink by interstitial cation or solvent molecules elimination after thermal treatments. When so many solvent molecules are still trapped in the material, the thermal treatment is likely to find a lower energy stable configuration, by eliminating the excess and consequently lowering the tension in the overall cell energy.
Best regards,
WNM
Another possibility: How do you measure crystallite size by XRD? If Scherrer equation, you really do not know what causes broadening. Annealing may reduce crystal imperfections (defects, dislocations, etc.), which cause peaks to sharpen. Sharper peaks look like larger crystallites if you are assuming size broadening.
Never assume all broadening is due to crystallite size (or any one contribution). Use Williamson-Hall or Warren-Averbach or such analysis to separate the various broadening contributions.
The particle or crystallise size is lowered since annealing is used in the fission process.
My question is:
for samples prepared at high concentration, it is assumed that the crystalline size increases after annealing, but the opposite has happened. I need to know, what happened during the annealing between crystallines ( growth mechanism) when the concentration was increased.
https://link.springer.com/article/10.1007/s40089-021-00343-z#:~:text=The%20crystallite%20size%20and%20lattice,(Zn2%2B)%20increased.
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