I performed XRD analysis on a functionalized solid core. After doping it with a metal, I observed a leftward shift in one of the peaks of the functionalized solid core. What could be the reason for this shift? Why does the peak shift to the left after metal doping?
Dear Eden Sinchana D'Souza
Usually a leftward shift in the 2theta position of a peak in XRD is due to an increase of the d-spacing of the crystal lattice. If the atomic radii of your dopant is larger than that of the crystal lattice of your material, the structural parameters of the lattice changes. You can calculate from the diffraction data the d-spacing, lattice parameter, crystallite size, dislocation density, texture parameter and strain of the structure unit cell, and compare to the powder diffraction file standars.
I attach an example of this.
Regards!
Article One-step, low temperature synthesis of reduced graphene oxid...
The shift in XRD peaks during doping is related to the size (ionic radius) of the dopant metals with related to the size of the host. If the ionic radius of dopant is lower than the host, the shift will be to the right, for the reverse case, the shift will be to the left. For further Information, just refer these articles
It is more complicated than Dagne indicates.
A peak shift to lower angles indicates in increase in lattice parameter (Bragg's law).
An increase in lattice parameter can be caused by a
- small dopant atom (probably much smaller than the rest of the atoms), if it is interstitial
- large dopant atom (slightly larger than bulk of the material), if it is substitutional
For completeness, a shift to greater angle indicates a decrease in lattice parameter. This is likely only caused by dopant atom too large to be interstitial but smaller than the bulk atoms.
- Badges
- Science topic
- Similar topics
- Mathematics
- Algebra
- Matrix