Optical properties of a grating-nanorod assembly structure for solar cells

• A grating-nanorod assembly structure applied to silicon solar cells is proposed.
• The average absorptance can reach 0.955 in the 300–1100 nm wavelength region.
• The high absorptance is attributed to guided mode resonance and microcavity effect.
• The transient and steady-state magnetic field distribution are plotted.
• The effects of incident angle on absorptance are discussed.

This paper proposes a grating-nanorod assembly structure that can be applied to silicon solar cells. The optical properties of the assembly structure are examined by applying the finite difference time domain method in the 300–1100 nm wavelength region, where the average spectral absorptance of the structure can reach 0.955. This high absorptance is attributed to guided mode resonance and microcavity effect. The transient and steady-state magnetic field distribution of the structure reveals the underlying mechanisms of such extraordinary phenomena. Absorptance is further investigated at different diameters and lengths of the nanorod component. The effects of incident angle on absorptance are also discussed. The solar cells of the structure can yield an optimum conversion efficiency of 25.91%. Thus, the proposed structure can be applied to silicon solar cells.