Enhancements of absorption and photothermal conversion of solar energy enabled by surface plasmon resonances in nanoparticles and metamaterials

Abstract

During the past decade, a great deal of research work has been carried out on near-field photonics and nano-optics relating to photo-thermal conversion process. In this paper, recent analytical, numerical and experimental studies on radiation properties in visible and near-infraed wavelengths of electromagnetic waves incident on nanoparticles and metamaterials with applications to solar energy harvesting are reviewed. These nanoparticles and metamaterials are made of both isotropic and anisotropic materials. Mie theory is employed for analyses of absorption properties of spherical nanoparticles composed of different materials. The finite difference time domain (FDTD) method and the rigorous coupled-wave analysis (RCWA) method are used for numerical studies of absorption properties of nanoparticles with arbitrary shapes and power dissipation density distribution of metamaterials, respectively. In addition, a perfect absorber with pyramidal nanostructures made of Bi2Te3 is proposed, and measurements of absorption properties of some fabricated metamaterials are summarized. Potential applications of these nanostructures for solar energy harvesting enhancement are discussed. The results of these studies have provided not only improved understanding of physical mechanisms in enhanced absorption of solar energy by nanoparticles and metamaterials, but also clarified contradictory explanations on the photo-thermal conversion process in solar energy harvesting as well.