Optical and thermal properties of P2O5–Na2O–CaO–Al2O3:CoO glasses doped with transition metals

The aim of this paper is to report the optical and thermal properties of V2O5 and CuO doped P2O5–Na2O–CaO–Al2O3:CoO glasses so as to investigate their possible use in solar collection applications. The optical absorption spectra of the glasses at room temperature were in the spectral range of 200–1100 nm. The optical band gaps of the glass samples were determined for direct and indirect transitions. When transition metal ions doped to the base glass, the optical band gap decreased. Changes in the refractive indices vs. wavelength for all the specimens were also examined by spectroscopic ellipsometry. By measuring the heat capacities and thermal diffusion coefficients of the specimens at varying temperatures, their thermal conductivities were calculated to be in the 320–620 K temperature range. The obtained glasses seem to be promising materials and can be used in solar collector applications.

Research highlights
► CoO incorporated black glasses were produced and doped by transition metal ions (such as V2O5 and CuO) to obtain technologically important glass structures.
► Optical properties were determined by Spectroscopic Ellipsometry for the first time.
► Thermal properties and band gap values were investigated.