2023 年 21 巻 4 号 p. 310-317
Absorption efficiency and performances of nanoparticles (NPs) for solar irradiance harvesting were investigated using quasi-static approximation of electrodynamics. This work considered gold (Au)- and silver (Ag)-based NPs in five configurations: solid, metal–graphene (MG), dielectric–metal (DM), dielectric–metal–graphene (DMG), and dielectric–graphene–metal (DGM). SiO2 and HfO2 were the dielectric materials of the structure or the host medium. The size-dependent Drude–Lorentz model determines the permittivity of the metal and the Kubo formula determines the surface conductivity of the graphene. The calculated results show that DGM NPs have the highest absorption performance compared to others with the same radius of 15.34 nm (including a 0.34 nm graphene layer). A SiO2–graphene–metal NP in HfO2 gave the best performance when the dielectric material and environment in the structure were exchanged. Furthermore, adding a graphene layer to an NP generates a secondary peak at a low frequency but reduces the primary peak. Additionally, the performance was enhanced by varying the core radius from 5 to 20 nm for a fixed-size DGM NP with a radius of 25.34 nm until it declines after reaching the maximum performance point. Also, the thickness of graphene influenced the performance of this structure. As a result, a DMG NP can be chosen to be applied in solar irradiance harvesting devices because this structure enhances the solar irradiance absorption performance.
