Ultrathin tandem-plasmonic photovoltaic structures for synergistically enhanced light absorption

Abstract

Recently, plasmonic nanostructures have been playing a key role in enhancing the optical absorption in thin film solar cells, which are poor absorbers due to their decreased optical travelling path length. Here, we have proposed and simulated a tandem ultra-thin silicon solar cell, in which each layer is integrated with metal nanostructures, using the FDTD method. The Si layers are disconnected via a SiO₂ layer with embedded Ag strips. The surface of the top Si layer and the underside of the bottom Si layer are connected to each other using contacts from a Ag periodic array nanostructure. The simulation results have demonstrated that the proposed structure has a synergistic effect on light absorption and gives rise to a 172% light absorption enhancement and 139% short-circuit current density enhancement over the whole usable solar spectrum, compared with the one layer bared structure.