Origins of sp(3)C peaks in C-1s X-ray Photoelectron Spectra of Carbon Materials

摘要

X-ray photoelectron spectroscopy (XPS) is among the most powerful techniques to analyze defective structures of carbon materials such as grapheme and activated carbon. However, reported assignments of defects, especially sp(3)C and sp(2)C, are questionable. Most reports assign sp(3)C peaks to be higher than sp(2)C peaks, whereas a few reports assign sp(3)C peaks to be lower than sp(2)C peaks. Our group previously reported that calculated binding energies of sp(3)C were basically lower than those of sp(2)C. This work clarified that one of the reasons for the prevailing ambiguous assignments of sp(3)C peaks is charging effects of diamond.