TEOS-regulated TiO2@SiO2 oxide composite coatings for broadband antireflection, photocatalytic self-cleaning and photovoltaic cover glass applications

Oxide composite coatings with tunable refractive index, high optical transparency and self-cleaning functionality are important for advanced glass-based optical and photovoltaic applications. In this work, TEOS-regulated TiO 2 @SiO 2 interfacial coatings were fabricated by a sol–gel dip-coating route to construct multifunctional antireflective coatings for photovoltaic glass. The effect of TEOS content on the SiO 2 shell/network formation around TiO 2 nanoparticles was systematically investigated. Increasing TEOS content improved particle dispersion, promoted TiO 2 @SiO 2 interfacial construction, reduced coating roughness and tuned the effective refractive index from 2.19 to 1.47. Based on this interfacial regulation, a three-layer coating consisting of a TiO 2 @SiO 2 bottom layer, a hybrid intermediate layer and an HMDS-modified SiO 2 top layer was designed as a multilayer optical architecture with sequential refractive-index variation. The optimized coating exhibited an average transmittance of 96.50% over 380–1800 nm. In addition, the TiO 2 -containing interfacial layer endowed the coating with photocatalytic self-cleaning behavior, enabling optical recovery after methylene-blue contamination under UV irradiation. An accelerated thermal-cycling aging test conducted in accordance with the relevant IEC 61215 procedure, together with abrasion testing, showed limited optical losses under the applied laboratory conditions. When applied to mini crystalline silicon photovoltaic modules, the coated glass increased the short-circuit current density and power conversion efficiency by 8.86% and 8.84%, respectively, in relative terms. This work demonstrates that TEOS-regulated TiO 2 @SiO 2 interfacial engineering is an effective strategy for developing self-cleaning antireflective coatings with laboratory-scale optical stability for photovoltaic cover glass.