I have made TiO2/Graphene nanocomposite films with varying compositions of graphene by doctor blade technique on ITO substrate and then annealed at 450 C. And recorded XRD, I found that in all graphene + tio2 samples, all the peaks shift toward higher angles w.r.t. pure Tio2 thin film.
Depending on the shift value in relation with the diffraction angle you can find the reason. Can be stress, difraction plane shift etc.
To evaluate the stress, I would refer to Noyan and Cohen's book. But you should also consider that you might have partially reduced the TiO2 or added a significant oxygen vacancy concentration by annealing in contact with carbon. Determining whether you have a residual stress or a change in the lattice parameters at zero stress requires analyzing multiple peaks at multiple angles to the surface.
1987Residual Stress
Measurement by Diffraction and Interpretation
Authors:
Dr. Ismail C. Noyan,
Prof. Jerome B. Cohen
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ISBN: 978-1-4613-9571-3 (Print) 978-1-4613-9570-6 (Online)
That means there is a uniform decrease in the lattice parameters similar to the homogeneous compression in the system, which yields shift to higher theta angles regardless the hkl indices while keeping Bravais lattice invariant.
Roughly speaking İnhomogeneous lattice strain results peak broadening but not unidirectional spectral shift.
Sir..if the original sample like TiO2 thin film in my case has good xrd pattern but when I have added 0.5 wt% graphene in it by direct mixing in mortar patsle and deposited by doctor blade, then a peak next to the main 25 degree peak lost..what would have happened ? or i should repeat the spectra..?
I confirm the anatase or rutile phase formation. In my experience sometimes the particles get crushed in mortar pastel also confirm the thickness is same if nanocrystals are formed and thickness is not enough u may not get sharp peak but a very broad amorphous type peak can be observed.
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