Hydrophobic antireflective coatings based on the synergistic effect of hollow and solid silica for application in photovoltaic modules

Abstract

Photovoltaic glass coatings with multiple functions, such as strong broad-spectrum antireflectivity, effective self-cleaning, anti-abrasiveness, stability, and durability, have great potential for improving and ensuring the outdoor operation of photovoltaic modules. In this study, alkali-catalyzed hollow and solid silica nanoparticles were mixed at controlled ratios by sol-gel method, and the resulting solution was modified with HMDS to improve hydrophobicity, and obtain refractive indices ranging from 1.45 to 1.13. Subsequently, based on the principle of gradient refractive index, a trilayer hydrophobic antireflective (TLHA) coating was developed, comprising a top layer (n = 1.13), a middle layer (n = 1.27), and a bottom layer (n = 1.44). The TLHA coating exhibited an average transmittance of 97.77 % in the wavelength range of 380–1800 nm, with a peak transmittance of 98.97 % at 572 nm, and a hydrophobic contact angle of 144°. Additionally, after 144 h of thermal cycling and 600 abrasion cycles, the average transmittance of the TLHA coating decreased by 2.43 % and 1.63 %, respectively, in the 380–1800 nm range, and the coating's pencil hardness reached 5 H. And further application results showed that the crystalline silicon micro-modules with the TLHA coating could exhibit a 7.63 % and 5.24 % increase in Jsc, as calculated from EQE and J-V curves respectively, and a 5.34 % increase in PCE, compared to modules without the TLHA coating. These results highlight the extensive applicability of the TLHA coating in enhancing outdoor photovoltaic operation efficiency, durability, and wear resistance.