Hierarchic random nanosphere model for broadband solar energy absorbers

In this paper, a light absorbing model based on the hierarchic structure with randomly distributed nanospheres is proposed for strong absorption over 400-900 nm. The effect of different parameters including the size range, the particle number and the hierarchic height of the nanospheres on the light absorption is systematically analyzed. It is found that this structure can absorb light efficiently with an average absorptivity of 91% at the 400-900 nm waveband. The great enhancement of light absorption can be attributed to the localized surface plasmon resonant of the random metallic nanospheres as well as the strong light scattering of the metallic nanospheres embedded in the dielectric film.