Enhancement of plasmonic photovoltaics with pyramidal nanoparticles.

Abstract

Light trapping as a result of embedding plasmonic nanoparticles (NPs) into photovoltaics (PVs) has been recently used to achieve better optical performance compared to conventional PVs. This light trapping technique enhances the efficiency of PVs by confining incident light into hot-spot field regions around NPs, which have higher absorption, and thus more enhancement of the photocurrent. This research aims to study the impact of embedding metallic pyramidal-shaped NPs inside the PV's active region to enhance the efficiency of plasmonic silicon PVs. The optical properties of pyramidal-shaped NPs in visible and near-infrared spectra have been investigated. The light absorption into silicon PV is significantly enhanced by embedding periodic arrays of pyramidal NPs in the cell compared to the case of bare silicon PV. Furthermore, the effects of varying the pyramidal-shaped NP dimensions on the absorption enhancement are studied. In addition, a sensitivity analysis has been performed, which helps in identifying the allowed fabrication tolerance for each geometrical dimension. The performance of the proposed pyramidal NP is compared with other frequently used shapes, such as cylinders, cones, and hemispheres. Poisson's and Carrier's continuity equations are formulated and solved for the current density-voltage characteristics associated with embedded pyramidal NPs with different dimensions. The optimized array of pyramidal NPs provides an enhancement of 41% in the generated current density when compared to the bare silicon cell.