Fabrication of superhydrophilic SiO₂-HNTs composite coating and its self-cleaning and anti-fouling performance on PV modules

Surface contamination of photovoltaic (PV) modules is a major constraint on their photoelectric conversion efficiency. To address this issue, we developed a multifunctional composite coating using a synergistic composite of SiO₂ and halloysite nanotubes (HNTs). The unique tubular structure of HNTs allows them to integrate uniformly with SiO₂, creating a nanostructured surface when dispersed in the coating. The aluminum hydroxyl groups (Al—OH) on the HNTs surface undergo condensation with the silicon hydroxyl groups (Si—OH) of SiO₂, forming robust Si—O—Si and Si—O—Al bonds. When combined with 3,4-ethylenedioxythiophene (PEDOT), a dense composite network is produced, resulting in a coating with substantially higher hardness and abrasion resistance than those based on SiO₂ or HNTs only. The coating exhibits both superhydrophilicity and antistatic behavior. These two properties work together to effectively minimize dust accumulation and improve light transmittance, thereby supporting stable and efficient power generation from PV modules. Furthermore, the coating demonstrates excellent anti-fogging and anti-corrosion performance. Test results revealed that under standard illumination conditions, the peak power output of coated modules increased by 1.33% compared to uncoated ones. In simulated dust accumulation environments with incident light angles of 45° and 75°, the power generation of coated modules rose by 19.8% and 44.8%, respectively, relative to uncoated modules. In addition to outstanding environmental adaptability and durability, this coating offers a cost-effective and practical route toward the surface functionalization of PV modules.