How reliable the powder XRD data is in case of small hybrid (metal @semiconductor) core shell nanoparticles say 12nm in size? Do you observe a small shift?
The sample is not highly crystalline.
It is depending on the types of interactions between the metal core and semiconductor shell. During the coating of semiconductor onto metal, if the surface of metal core is oxidised or formed any metal compound then the XRD peak intensity and position may change. If not occur any chemical change of metal core there is no shifting in XRD patterns. However, there might be find a new broad signal for the semiconductor materials depending on the nature of crystal structures and thickness of the coating layer onto metal surface.
It is depending on the types of interactions between the metal core and semiconductor shell. During the coating of semiconductor onto metal, if the surface of metal core is oxidised or formed any metal compound then the XRD peak intensity and position may change. If not occur any chemical change of metal core there is no shifting in XRD patterns. However, there might be find a new broad signal for the semiconductor materials depending on the nature of crystal structures and thickness of the coating layer onto metal surface.
Thanks, but what if the metal core is too small in size, 4nm.
Do you still observe peaks from the core?
Yes, broader XRD signal due to smaller size of MNPs. Because the incident X-Ray can easily penetrate this thickness (12-4 = 8/2 = 4 nm) of the semiconducting layer.
In the case of core-shell structures, the shift of XRD peaks is expected specially when the core size is very small. This is, in addition to the effect of the extreme surface tension of the small particles, mainly due to the effect of the interfaces between the core and shell materials which are, in most cases, semi-coherent and/or in-coherent.
Better if you do the PL study to confirm the formation of core shell structure.
Sagar Rawat PL study? You mean Photoluminescence? I have already done TEM on those particle and they are core shell according to the contrast difference and lattice fringes and various other reasons.
PL will help only in case of fluorescent particles I think.
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