Inorganic‐Nanoparticle‐Based Super‐Hydrophobic Colored Coatings for Sustainable Building‐Integrated Photovoltaics

Abstract Building‐integrated photovoltaics (BIPVs) have gained significant attention by promising renewable electricity without concerns of additional space, environmental damage, and maintenance problems. However, silicon‐based BIPVs generally limit aesthetic appearance due to their monotonous dark blue modules. In addition, maintaining performance is challenging because BIPV modules are easily contaminated by particulate matter, hindering practical applicability. In this study, a solution‐based process of functional nanoparticles (NPs) is employed to fabricate large‐area colored films with self‐cleaning properties. The stable and robust NPs comprising inorganic‐based fluorinated silica (F‐SiO₂) NPs and silica‐coated gold (Au@SiO₂) NPs are synthesized for self‐cleaning and aesthetic integration, respectively. The NPs are then self‐assembled into a hierarchical structure with the aid of a silicone‐based binder over a large area (1 m²) using customized convective‐assembly equipment, resulting in tunable colored hydrophobic and super‐hydrophobic surfaces. Finally, they are applied on the front glass of BIPV modules of a 3 kW solar system on a constant over 1 year, with a system energy efficiency of ≈89.5%. Moreover, the colored glass modules show excellent stability after damp heat (85 °C/85%) and accelerated weathering tests. Hence, they are expected to be utilized as a functional colored film for sustainable BIPVs.