Hot-embossed microcone-textured fluoropolymer as self-cleaning and anti-reflective photovoltaic module covers

Superhydrophobic self-cleaning covers, exhibiting small roll-off angles of water droplets, mitigate the soiling of photovoltaic (PV) modules. In this work, microcone-textured fluorinated ethylene propylene (FEP) covers attached to the front side of PV modules offer improved performance via dual functionality, namely via self-cleaning and reduced parasitic reflection losses. The aspect ratio of the FEP microcone-textures was investigated in view of both functionalities. The best performing microcone-textured cover (aspect ratio of 0.7) demonstrated a significant enhancement in short-circuit current density (JSC) of 3.1% relative when applied to Cu(In,Ga)Se2 solar cells. Furthermore, compared to a planar FEP layer, the microcone-textures showed superior self-cleaning capability when tested using different soil types. Microcone-textured FEP recovered 100% and 65.8% of photocurrent generated when soiled with sea sand and Arizona test dust, respectively. We also present robust microcone-textured FEP covers such that superhydrophobicity was still achieved even with truncated microcones.