You can verify by following methods: Morphological analysis, SEM-EDX, FT-IR, XRD, TEM, and so, on.

Further optical investigations like absorpbance, PL too helps.

I hope this might help you.

Thanks,

Vasanth

If these are small quantum dots, showing carrier confinement effects, then probably only TEM or STEM will be able to directly confirm or falsify their existence. As Pb is much heavier than the other elements, if it is enriched in the core then it may be difficult to prove by imaging methods (as round particles will be thicker in their centres in projection you would get stronger scattering from there anyway, i.e. imaging a Pb-rich shell is easier than imaging a Pb-rich core). So STEM-EDX may be the best method.

Thank you Mr. Thomas Walther and Mr. Vasanthan. Thanks for the answers.

By the way, from the PL, how can we confirm the sample is in a core shell structure?

Thanks.

not without detailed modelling, I guess, and even then results may not be unambiguous; hence, a direct imaging method is the method of choice.

Thank you very much Mr. Tomas Walther.