Self-assembled nanostructured composites for solar absorber

Nanostructured composites designed for highly efficient solar energy absorption and conversion were studied. Self-assembled nanostructure was constructed on the Fe-Cr-Ni alloy surface directly through electrochemical treatment by applying potential of wave pulse in a mixed solution of sulfuric and chromic acid. The surface structure, featuring 2D quasi-periodic nano-needle array, was composed by a mixture of spinel oxides of the substrate elements. Film of this structure displays absorptivity of 99% over the solar spectrum (0.3-1.5 μm), with low thermal emission in the IR region. The high selective absorption capability of nanostructured composites realizes efficient energy conversion and could be accepted in practice.