I have calculated band gap of cerium oxide using UV-vis absorption spectra and PL emission spectra. The values of band gaps calculated by both technique differ by ~ 0.7eV. What can be the possible cause behind this difference?
While changing the method and calculating the bandgap, the difference should be within (0.01-0.1). 0.7 is a very large difference. The reason is related to the difference between emissions and absorptions process. Read more about both techniques and choose the most suitable one for your calculations.
Emissions process is much more longer than absorption. Many processes (solvent relaxation) can lead to stabilization of excited state hence lowering of the band gap as compared to absorption.
While changing the method and calculating the bandgap, the difference should be within (0.01-0.1). 0.7 is a very large difference. The reason is related to the difference between emissions and absorptions process. Read more about both techniques and choose the most suitable one for your calculations.
Prof. Mudila,
you have not mentioned the name of techniques that was used for charecterization, Anyhow;
While changing the technique minute change in difference is ok but 0.7 is the huge difference. The difference in band gap depends upon various factors:
1. how the tangents fixed for band gap calculation.
2. calculation of band gap for which absorption peaks (first, second or third ?)
Better to calculate the band gap with multiple no.s of sections.
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