Nanoimprint-textured Glass Superstrates for Light Trapping in Crystalline Silicon thin-film Solar Cells

Recent progress in Liquid Phase Crystallization (LPC) of silicon enabled reaching a material quality of thin-film silicon solar cells on glass comparable to multicrystalline silicon wafers. However, decreasing the absorber thickness requires taking measures for efficient coupling and trapping light into the solar cell device. Here, we successfully integrated different periodic sub-micrometer sized structures at the sun-facing air-glass superstrate interface of 5 x 5 cm2 LPC silicon thin-film solar cells by nanoimprint lithography. These structured superstrates were modularly attached to the device and found to provide both, anti-reflective and scattering properties. In this study, the influence of the structure type and geometry is examined. With the structures used an enhancement in short-circuit current density of + 5% (relative) compared to the planar device could be achieved.