Hello, everyone. I have synthesized some nano particles and want to find out their band gap energies. I have found the Tauc method and the Kubelka–Munk equation, used to calculate band gap energies in previous literature. I need your help to carry out these methods.
Dear Mukherjee,
As far as I know, we can find an intercept point, as the optical bandgap, of the [F(R)hν]² using Tauc plot. F(R) is the Kubelka-Munk as a function of energy (hν).
Best regards.
@ Shibghatullah Muhammady
Thanks Sir, for your kind attention. I want to know how to plot it. Can you provide me any tool for these?
Thank you, Sir, @ Ahmed Y. Yassin.
I want to inform everyone that I want to know about the technique of the Kubelka–Munk plot. So, Please provide some files that will help in this purpose.
Hello Arnab Mukherjee,
Tauc method and the Kubelka–Munk function are relatively complicated techniques and requires a lot of parameters to be determined, like film thickness and so on.
But I found the method for determination of the absorption edge and optical band gap directly from the UV-Vis spectra. It is described in the article:
Article Flame-excited luminescence in the oxides Ta 2O 5, Nb 2O 5, T...
(See part 4. Absorption edge measurements).
I used it for my TiO2-based fibrous materials and I agree with the authors, it is a really good technique, especially if you are working with photocatalysts or you need to characterise the optical properties of the material.
I hope it will help You.
You should use Tauc's plot and Kubelka Munk functions for band gap evaluation:
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Whatever method you eventually apply, please first study the underlying concepts so that you know what to do from your own study. Just as an example: to apply the Tauc plot methodology you need to know the character of the relevant optical transition (direct vs. indirect, allowed vs. forbidden). Concerning the Kubelka Munk method, it is based on an over-simplification of the scattering process in the sample. There are improvements available in the literature which come at very little computational cost. Yet, you really need to understand the underlying assumptions in order to not run the risk of producing wrong results.
Whenever, in studying the concepts and methods, new questions arise, come back to ask them. Concerning the methods in question here, you will find good and less good discussion threads about them. Most of the time, the "easy" ones are less fruitful...