XPS investigation of atomic environment changes on surface of B2O3-Bi2O3 glasses

Melt derived glasses of (1-x)B2O3∙xBi2O3 system with 0.1 ≤ × ≤ 0.875 were investigated by X-ray photoelectron spectroscopy (XPS) in order to evidence the structural changes that occur at the surface of bismuth borate glasses as Bi/B ratio increases from 1:9 to 7:1. The high resolution XPS spectra of O 1s, Bi 4f and B 1s photoelectrons emphasizes consistent changes in the vicinity of oxygen, and small changes around bismuth and boron atoms by increasing of Bi2O3 content. The deconvolution of O 1s spectra was used to investigate the Bi/B ratio effect on the number of bridging and non-bridging oxygens and the results obtained were discussed considering four components occurring from oxygen atoms implied in BOB, BOBi, BiOBi and BO/BiO bonds. From the deconvolution of Bi 4f high resolution spectra, four components related to Bi0 and bismuth atoms connected in bonds of BiOBi, BOBi and BiO types were identified. It was concluded that boron and bismuth play a network former role in the entire compositional range.