The photolectron binding energies are characteristic of the irradiated atoms, permitting identification of all elements with the exception of H and He. For polyimide, C, O and N are seen. Also, XPS is quantitative: The intensities of photoelectron peaks are directly proportional to the number of atoms present. Therefore, using elemental sensitivity factors, peak intensities can be converted to atomic concentrations with a relative error of ~10%.
Chemical state determination: The polyimide C 1s peak
The exact binding energy of core electrons is determined by the local chemical environment, permitting the identification of nearest neighbor bonding or oxidation states. For PI, 4 separate carbon features are found.
(C:0.25, O:0.66, N:0.42),
peak intensities are converted
into atomic concentrations
(C:74%, O:20%, N:6%)
Relative error < 5%
Theory: C:75.9%, O:17.2%, N:6.9%