Concentrator Solar Power (CSP) technologies use mirrors to concentrate the Sun’s light energy on a small area called receiver. This technology is gaining interest of many researchers due to its high potential to generate power best during the late afternoon hours and to potentially displace the use of fossil fuel plants that emit the greenhouse gases that cause climate change. One of the crucial challenges of CSP technology is lack of a high-performance solar absorbing material at high temperature. Therefore, the present work is focused to synthesize cobalt oxide nanoparticles and testing of these particles as solar concentrator receiver. These particles are synthesized by sol-gel method with varying concentration of precursors. Further, the surface morphology of these particles are analyzed using Scanning Electron Microscopy (SEM). The crystal structure of cobalt oxide is confirmed by X-ray diffraction studies. To study the optical properties of prepared samples, FTIR and UV-Visible-NIR spectroscopies have also been done. Synthesized black oxide Co3O4 nanoparticles are dispersed in locally available solar absorber materials and different samples are prepared. The composite of cobalt oxide nanoparticles and black matt paint are characterized by UV-Vis-NIR spectroscopy. The mixing of cobalt oxide nanoparticles in solar absorber paint increases the absorbing capacity of the paint.