Periodic nano-textures enhance efficiency in multi-junction silicon thin-film solar cells

In this work, we report on the prototyping of thin-film silicon tandem solar cells with periodic light-trapping textures. Our approach combines an industrial applicable nano-imprint process, for the fabrication of advanced light management concepts, with state-of-the-art thin film silicon solar cell technology. In a joint experimental effort between project partners of the European thin-film silicon project "Fast-Track", we demonstrate that optimal periodic light-trapping nano-textures at the front-side of a multijunction solar cell enhance the power conversion efficiency of the device in comparison to solar cells with conventional textured TCO (transparent conductive oxide) front contacts from 11.7% to 12.1%. This improved power conversion efficiency is mainly driven by an enhancement of the short-circuit current density through the use of periodic light-trapping nano-textures. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim