I found a paper on why I received a peak at 212 nm, for UV-Vis spectroscopy, when the absorption range should have been around 250 to 370 nm depending on the preparation process.
The paper said "The UV-Visible absorption spectroscopy of ZnO nanoparticles in ethanol solvent shows an excitonic absorption peak at about 214 nm, which lies much below the band gap wavelength of 388 nm of bulk ZnO. The peak at ~214 nm is due to interband transition of copper electron from deep level of valence band. The blue shift in the peak centered at ~214 nm in absorption spectra may be due to the transition of electrons from the more inner shell of copper to the uppermost shell as time passes. It is possible that, due to aggregation and agglomeration, particle size increases and material settled down on the bottom of container causing decrease in the absorbance"
I don't understand the relevance of a copper transition band here.I would be much appreciative if someone was able to explain what this means.
I am attaching the paper for more information.
Thank you.
The UV cut-off wavelength for ethanol solvent is 210 nm. Pl. check whether the peak you get is by virtue of solvent and it may deviate if it is impure.
The solvent I used was distilled water sir. I did the analysis in the form of a nanosuspension.
when the size of nano particles of ZnO is very low, the band gap will increase and the wavelength is decreased also.....
What is the optical gap (or band gap) for your ZnO...As Luma Ahmed suggested, what is the size of ZnO you are dealing with, 10nm or 5nm or 1nm???
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