Raman spectroscopy-in situcharacterization of reversibly intercalated oxygen vacancies in a-MoO3

Abstract

This work reports on thein situstrategy to reversibly generate or suppress oxygen vacancies on a-MoO3which were probed by Raman spectroscopy. Reversible changes in two features of the a-MoO3Raman spectrum could be correlated to the generation of oxygen vacancies: displacement of the Tbband frequency and the intensity decrease of the symmetrical stretching (?s) band. These two features could be used to qualitatively describe oxygen vacancies. Raman results also indicate that oxygen vacancies are located in the interlayer region of the a-MoO3lattice. This observation is corroborated byin situX-ray diffraction, which also indicates the absence of nonstoichiometric phase transitions.