Synthesis and optical characterization of C-SiO2 and C-NiO sol-gel composite films for use as selective solar absorbers

Abstract

The authors present a cheaper and environmentally friendly method to fabricate efficient spectrally selective solar absorber materials. The sol-gel technique was used to fabricate carbon-silica (C-SiO2) and carbon-nickel oxide (C-NiO) composite films on aluminium substrates. UV-Vis and FTIR spectrophotometers were used to determine the solar absorptance and thermal emittance of the coatings. C-NiO coatings gave the best spectral characteristics. The authors then show that it is possible to achieve a solar absorptance of 0.94 and a thermal emittance of 0.12. So far, to our knowledge, no commercial spectral solar absorber has these spectral responses