Design of a Plasmonic Photocatalyst Structure Consisting of Metallic Nanogratings for Light-Trapping Enhancement

Abstract

In this paper, a novel SPP-based photocatalytic system with high photocatalytic performance consisting metallic nanograting elements is proposed and simulated numerically with finite-differential time-domain (FDTD) method. Various nanograting metallic shapes, rectangular and trapezoidal, are studied. Results shows that the absorption significantly increases for the trapezoidal grating-based structure compared to its flat and rectangular grating elements. In addition, the effect of the incident angle of the sun light is considered to achieve an optimum design. It is found that in all angles of the incidence, trapezoidal grating (TG) has larger visible photocatalytic activities than the flat and rectangular cases. The best configuration was realized for the trapezoidal grating-based structure at 60° of inclination when the height of the grating elements is 43 nm. The photocatalytic activity of the metallic grating structure was attributed to scattering of the incident light and return to the host TiO2 medium and the surface plasmon excitation of the metallic elements.