Comparison of bioinspired hillock and pit textures for silicon solar cells

Inspired by the apposition compound eyes of some dipterans, we analyzed the effect of texturing the exposed face of a silicon solar cell by ray-tracing simulation. Bioinspired textures of two types were considered: hillock textures and pit textures. A multifrequency analysis-that took into account the broadband nature of solar radiation and its amplitude at the sea-level, as well as the wavelength dependence of the complex-valued refractive index of silicon-showed that both types of bioinspired textures are beneficial. We found that the light-coupling efficiency can be enhanced by as much as 20% and 24% with respect to that of a flat surface when the exposed face of a silicon solar cell is decorated with the bioinspired hillock texture and the bioinspired pit texture, respectively.