Light Trapping in Monocrystalline Si Solar Cells Using Back–Side Diffraction Gratings
Back–side diffraction gratings enhance a solar cell’s near–band–gap response by diffracting light into higher orders and thereby reducing front–side escape losses. The resulting increased photon absorption and carrier generation improves short–circuit current densities and solar cell efficiencies. Combining rigorous coupled–wave analysis and ray tracing yields a three–dimensional, polarization sensitive optical model to calculate Si absorbance, front–side and back–side losses. For industrially used, pyramidally textured, 180 μm Si solar cells with 85 nm SiNx anti–reflection coating, the application of an optimized back–side grating enhances the short–circuit current density by ≈ +1 mA/cm2, a relative increase of ≈ +2.7 %.
W. Jantsch and F. Schäffler
R. Rothemund et al., "Light Trapping in Monocrystalline Si Solar Cells Using Back–Side Diffraction Gratings", Solid State Phenomena, Vols. 178-179, pp. 446-450, 2011