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 mu m), 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. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.