Direct structuring of a biomimetic anti-reflective, self-cleaning surface for light harvesting in organic solar cells.

A one-step method to fabricate a biomimetic dual-scale hierarchical structure for a transparent anti-reflective, self-cleaning layer for organic solar cells is reported. Template-mediated UV replica molding is used to directly create a multi-functional surface with an acrylate-functionalized perfluoropolyether without complicated processing steps. The surface exhibits superhydrophobic properties and self-cleaning characteristics. In addition, the surface leads to an enhancement of photovoltaic power conversion efficiency by ≈10% as a result of reflection suppression and transmittance enhancement. The method can easily be applied to large area substrates (22 cm × 24 cm) in a cost-effective manner. Furthermore, the solar cell can withstand harsh outdoor conditions for a long time, without a notable change in the device performance, owing to robust surface layer and non-fouling properties.