Preparation and characterization of nanocomposite of Co:CuO by radio-frequency sputtering for solar selective absorber application

In this work, CuO thin films with different cobalt percentages were deposited, at room temperature on glass and copper substrates, using radio-frequency sputtering under 30% oxygen partial pressure. The effect of Co content on structural, electrical, morphological and optical properties of CuO films was investigated in detail. The X-ray diffraction measurements revealed a polycrystalline monoclinic structure for all sputtered films. Raman analyses showed a peak broadening and shift due to the quantum confinement effect in the copper oxide nanoparticles. Adding cobalt leads to the decrease of the crystallite size and the band gap energy. Electrical measurements showed that the film conductivity increases with the Co content. All films exhibited good solar selectivity (>12) with high solar absorptance (> 92%) and low thermal emittance (< 7%). The obtained Co:CuO thin films could be suitable as potential candidates for selective absorber applications in CSP technology.