Colloidal plasmonic structures for harvesting solar radiation

Direct Solar Absorption Collectors explore the thermo-optical properties of fluids to convert solar radiation into thermal energy. Colloids of metallic nanoparticles have shown a great potential to convert solar radiation into thermal energy efficiently, because of the matching between the absorption peak of the localized surface plasmon resonance and the solar radiation spectrum. Recently, multilayered metallic nano structures have been broadly studied for Thermo-optical applications due to the possibility to tune the plasmon resonance next to the near infrared region. In this work, using a full-wave field numerical model, we study the solar absorption of metallic nanofluids composed of Solid structures (Sphere, Cube, Tetrahedral, Octahedral), Silica-based structures (Shell and Multilayered) and its elliptical versions. Although a large part of the metallic material is replaced for SiO2 in the nanofluid composition of NanoShell (NS) and Multilayered (ML) structures, the values of solar radiation absorber coefficients are larger than the obtained with solid particles. Also, the quantity of metal is just 18% (NS) and 53% (ML) of the material necessary to fabricate colloids of solid particles. For the elliptical structures, the values of solar radiation absorber condition are larger than the obtained with spherical structures.