Hollow MgF2@TiO2 self-cleaning nanocoatings for photovoltaic performance enhancement

The efficiency of photovoltaic (PV) modules, the core unit for converting solar energy to electricity, is limited by the reflection loss of the glass cover and the adsorption of organic pollutants. Thus, the development of coatings with antireflective and self-cleaning composite functions is important. In this study, based on the sol-gel method, hollow MgF 2 /TiO 2 (MgF 2 @TiO 2 ) composites were prepared and, combined with the Essential Macleod software, coatings were designed and optimized. Using this approach, a three-layer antireflective coating with a self-cleaning function was developed. Moreover, subjecting the MgF 2 @TiO 2 composites to 24 h heat treatment resulted in the production of MgF 2 with a stable hollow rod structure and a refractive index of 1.18. The photocatalytic performance of TiO 2 was enhanced by optimizing the annealing temperature, and the strongest effect was achieved at 300 °C. In addition, the optimization of the coating structure resulted in a gradient refractive index coating with high process tolerance, with an average reflectance of 0.81% in the visible wavelength band. The application of the coating to mini-PV modules increased the light transmittance to 97.58% and the efficiency of the module by 5.71%, with a strong self-cleaning effect. The coating was demonstrated to have excellent durability and reliability upon exposing it to 2000 h of damp heat and subjecting it 1000 abrasion cycles. This study promotes the design and application of functional coatings on the surfaces of PV modules.