Enhanced dust removal stability of highly transparent superhydrophobic coatings by ultrathin ZnO “nano-armor” conformal micro/nanostructures

Transparent superhydrophobic coatings provide passive self-cleaning and dust removal functionality for photovoltaic (PV) modules to sustain the energy conversion efficiency, which is highly dependent on micro/nanostructures of coatings. However, it remains challenge to enhance the micro/nanostructures robustness of such coatings while preserving their optical transparency, self-cleaning and dust removal functionality. Herein, we proposed dense and conformal “nano-armor” by atomic layer deposition (ALD) on transparent superhydrophobic coatings to enhance their resistance to particle impact and structural durability. Experimental results revealed that the ALD-treated coating (SZ90-F) maintained the high optical transparency (89.27 %) and superhydrophobicity with water contact angle of 160.3°, while also exhibiting excellent dust removal efficiency of 99.23 %. Meanwhile, the SZ90-F coating retained the superhydrophobicity and excellent dust removal performance after exposure to 6000 g of sand and 4000 g of water droplets, respectively. Mechanism analysis revealed that the enhanced durability of the transparent superhydrophobic coatings originated from the ZnO layer deposited by ALD, which formed strong chemical bonds on the micro/nanostructures surface, resulting in a continuous “nano-armor” structure, thereby providing effective protection against dust impact and preventing damage to the micro/nanostructures. This study provides a novel strategy for designing durable, transparent superhydrophobic coatings with enhanced mechanical robustness.