I want to quantify light absorption of a piece of solid sample. I use UV-Vis Spectrometer with an integrating sphere. Result of the measurement is %R. Besides the R, the transmission part is very very small. So %T can be ignored. K-M model is the most popular model to calculate the absorbance from the R data. In my case can I simply quantify the absorption by %A = 100% - %R ?
if you are using reference material for solid sample, your calculation for % A is OK.
Are you interested in the absorbance (Lambert-Beer / Kubelka Munk) or in the absorption, which is A = 1 - T - R ?
Dear Thomas,
Thank you very much for your reply.
I am interested in both of them. Could you explain for me how can I calculate the absorbance and the absorption for my sample. (For more detail of my sample: it is a layer of TiO2 with thickness between 10-20um, more exact it is TiO2-x because of some oxygen vacancies.)
Do your samples have a smooth surface? Then I would either go for a spectroscopic ellipsometry measurement (the result can be directly converted to yield the complex dielectric function from which you can obtain the index of absorption and thereby absorbance) or for a reflectance measurement from which you can obtain the dielectric function through a Kramers-Kronig analysis. Measuring the diffuse reflectance and applying Kubelka-Munk is something which I would do as a last resort since it is not Maxwell equations compatible method.
Unfortunately not. I'm no expert in ellipsometry but my guess is that the roghness of the sample would need to be much smaller (roughly probably less than a tenth of the lowest wavelengths you are interested in) and your sample should have a shiny appearance.
- Badges
- Science method
- Similar topics
- Methodology
- Absorption Spectroscopy
- UV-Visible Spectroscopy