high performance thermal coating comprising (cuo:nio) nanocomposite/c spectrally selective to absorb solar energy

Anovel nanocomposite consisted of nanomaterials as (cuo:nio) and carbon (fuel ash) were designed to absorb solar energy. thin films were made via casting and spin coating of the dopants nanocomposite thin films, containing different concentration ratios of cuo:nio. these thin films are precipitated on a glass and copper substrates. the optical properties of the doped fuel ash films with nanoparticles were measured in the range of 250-1300 nm. the intensity of solar radiation was measured too. the data were analyzed and interpreted in terms of the theory of phonon-assisted direct electronic transitions. the eg of the doped c was measured with different concentration ratios of (cuo:nio) (a=0.5:2.5, b=1:2, c=1.5:1.5, d=2:1, e=2.5:0.5) wt. %, with a fixed concentration of c of (7) wt.%. the results of the doped samples revealed an energy gap of (2.5-3.9 ev) and the absorptivity ranged from (85-99 %) for all nanocomposites. the energy gap of this nanocomposite system is very similar to those of semiconductor and has high efficiency to absorb the solar energy radiation. in addition, the results showed that the heat absorbed by the samples subjected to solar energy on the surface would be a selective surface. thus, the synthesized coating will be utilized on a flat plate collector as a trap to absorb solar energy.