Multimetal plasmonic nanomaterials for solar energy harvesting

Efficient broadband solar absorbing coatings could significantly enhance the performance of Si solar cells. Here, we present the design of novel SiO$_{2}$-based nanomaterial coatings based on multimetal plasmonic absorption. By implementing an efficient homogenization procedure based on the tight lower bounds of the Bergman-Milton formulation {[}Garcia et al. Phys. Rev. B, 75, 045439 (2007)], we have predicted the absorption coefficient of a quaternary nanocomposite consisting of Cu, Ag, and Au nanospheres embedded in a SiO$_{2}$ host matrix. A simulated annealing algorithm was used to predict nanocomposite properties (particle size and volume fractions) which result in a broadband absorption (350 - 800 nm) that matches the shape of the solar emission. These results show that novel optical materials can be made from multimetal-dielectric nanocomposites.