There are many from of Kubelka-Munk function I have found in literature:
1. F= (1-R)2/2R
2. F= (1-R2)/2R
3. F(hv)= (1-R(hv))2/2R(hv)
Again to calculate direct band gap some used (Fhv)2 where some used F.(hv)2. Same things are found for indirect band gap.
I am confused. Please give me a clear explanation to calculate band gap of powder sample from reflectance data.
Dear colleague Rana,
Have a nice time and good day
Please check the 7 attached papers.
I wish this is useful and help you.
Yours
A. El-Denglawey
Dear A. Eldenglawey,
Your files were very helpful to an article that I have been writing. Could you inform the reference of the file number 3? It will help me to improve this paper and I would want to cite the document properly.
Best regards
Kubelka-Munk provides the conversion of reflectance data into a parameter named F(R), which is proportional to the rate between absorption coefficient (alpha) and scattering (S). The scattering is almost constant for all the wavelengths, therefore, knowing the F(R) behavior we also know the behavior for alpha. Lastly, Tauc plot is constructed assuming F(R) = alpha, i.e., (F(R)x h x freq.)^n. The nature of transition "n" needs to be known, but it is a information easily found in literature (estimated by DFT for instance). I usually assume the Y axis from Tauc plot as arbitrary, because only the behavior for F(R) and alpha are the same; but the values of these parameters are not.
both equations are right, the first equation assumes that R does not change with the thickness of the material. the second equation is used when R does not change with the concentration of the material however, in this case, F(R) is proportional to the thickness. you should determine in which case you are.
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