The effect of B2O3/CdO substitution on structural, thermal, and optical properties of new black PVB/Cd semiconducting oxide glasses

Novel semiconducting P2O5–V2O5–(B2O3/CdO) oxide glasses containing high ratios of V2O5 and P2O5 were synthesized with melting–quenching method and their characterizations were performed. B2O3 were gradually replaced with CdO within the structure. Structural characteristics of the synthesized glasses were determined with XRD, SEM–EDS, and Fourier transform infrared spectroscopy (FTIR) with diamond ATR. Amorphous character of the glasses was determined with XRD and supported additionally with SEM images. The presence of CdO within the structure was confirmed with EDX spectrum. Structural units of vanadium, phosphate, and boron were determined with FTIR examination. CdO was observed to be present in the structure as a modifier. According to DSC data, glass transition (Tg), crystallization (Tc), melting (Tm) temperatures, and thermal stabilities (ΔT) were determined, and their relation with B2O3/CdO substitution was explained. According to DSC data, Tg decreased to 425 °C from 431 °C with the replacement of B2O3 with CdO; Tc, increased to 509 °C from 494 °C. Thermal stabilities of the synthesized glass samples increased to 84 °C from 63 °C. Transmittance and absorption spectra were obtained between the range of 200–3000 nm, and the transmittance belonging to the samples was observed to start around 1800 nm. Direct and indirect optical band gaps were determined with Tauc method. In addition, Urbach energies of the samples were determined and obtained results were evaluated. The newly synthesized cadmium–vanadium–phosphate glass is appropriate to be used as an absorbent layer in solar energy systems.