X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy and electrical conductivity studies of copper phosphate glasses

Phosphate glasses containing CuO with composition (CuO)_x(P₂O₅)_1-x, where x = 0.1, 0.2, 0.3, 0.4 and 0.5, were studied by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and room temperature electrical conductivity, σ. The spin orbit components Cu 2p _{3 2} and Cu 2p _{1 2} show doublet structures which may be associated with Cu⁺ and Cu²⁺. The ratio C = Cu⁺ Cu_total as a function of x was determined using the Cu 2p _{3 2} spectra. It is observed that the ratio, C, initially decreases with x, becomes minimum at x = 0.3 and then increases. Although the variation of σ with C was very small, it is close to the uncertainty in the measurement of its value; nevertheless it was maximum at C = 0.5, in agreement with the previous prediction. The FT-IR spectra indicated a maximum shift in the P = O absorption at 30% CuO contents in the glasses, which essentially follows the same pattern as the shift for the POP absorption. Further, the development of the high energy component peak in the O 1s (associated with POP oxygen) spectra follows a trend similar to the 760 cm^-1 (also associated with POP) absorption band in the FT-IR spectra.