XPS study of lead vanadate glasses

Abstract EN

X-ray photoelectron spectroscopy (XPS) has been used to obtain structural information from the Pb 4 f, V 2p, and O 1s core level photoelectron peaks in glasses of general formula xPbO–(1–x)V2O5 where x = 0.22 and 0.54.

The Pb 4 f7/2 peaks was symmetrical for the x = 0.22 glass and asymmetrical for the x = 0.54 glass and was therefore fitted with two contributions, one from Pb atoms forming PbO3 trigonal pyramids, and the other from Pb atoms forming PbO4 square pyramids.

The V 2p3/2 peaks were also asymmetrical and fitted with two contributions, one from V4+ ions and the other from V5+ ions.

The concentration of V5+ was high in the x = 0.22 glass and no V4+ ions were detected in the glass with x = 0.54.

The O 1s spectra show asymmetry for the samples having the composition x = 0.22.

For this glass composition, the O 1s peak was fitted with two contributions, one from oxygens in the configuration V–O–V, called bridging oxygens, and the other from oxygens in the configurations V–O–Pb and Pb–O–Pb, called non-bridging oxygens.

For x = 0.54, the O 1s spectrum was symmetric and was fitted to a single peak.

This is explained by the fact that the polarization of Pb atoms grows with the increase in PbO content in the glass and the Pb–O bond becomes covalent at x = 0.54.

The oxygen atoms in the three configurations, V–O–V, V–O–Pb, and Pb–O–Pb are of the bridging type and therefore the contributions to the O 1s core level spectrum from these three configurations for the x = 0.54 glass composition are undistinguishable.