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Opt Express. 2010 Mar 15;18(6):5525-40. doi: 10.1364/OE.18.005525.

High performance solar-selective absorbers using coated sub-wavelength gratings.

Author information

1
Dept. of Electrical Engineering, Stanford University, Stanford, CA 94305 USA.

Abstract

Spectral control of the emissivity of surfaces is essential for efficient conversion of solar radiation into heat. We investigated surfaces consisting of sub-wavelength V-groove gratings coated with aperiodic metal-dielectric stacks. The spectral behavior of the coated gratings was modeled using rigorous coupled-wave analysis (RCWA). The proposed absorber coatings combine impedance matching using tapered metallic features with the excellent spectral selectivity of aperiodic metal-dielectric stacks. The aspect ratio of the V-groove can be tailored in order to obtain the desired spectral selectivity over a wide angular range. Coated V-groove gratings with optimal aspect ratio are predicted to have thermal emissivity below 6% at 720K while absorbing >94% of the incident light. These sub-wavelength gratings would have the potential to significantly increase the efficiency of concentrated solar thermal systems.

PMID:
20389569
DOI:
10.1364/OE.18.005525
[Indexed for MEDLINE]

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