Tailored highly transparent porous silica coatings for enhanced optical and mechanical performance of solar covers

• Tailored durable anti-reflective coatings were designed through induced porosity using a pore-forming agent (Pluronic® P-123). • An increase of up to 5.2 % in optical transmission was achieved compared to bare glass. • Extended thermal treatments weakened the silica network, leading to reduced mechanical resistance • The silica precursor ratio was found to significantly influence coating density. • Adjusting the silica precursor and pore-forming agent concentrations affected the environmental durability of the coatings. Sol-gel porous silica-based anti-reflective coatings (AR) represent a key solution to minimize reflectance losses and improve solar systems efficiency. However extreme climatic conditions compromise the long-term durability of the coatings. This study focuses on the impact of pore-forming agent (Pluronic® P-123) concentration, thermal treatment, and silicon precursor ratio on optical, structural, and environmental durability properties. The introduction of Pluronic® reduced the refractive index, achieving a minimum value of 1.215 at 600 nm, corresponding to a porosity of 56 %, and increased optical transparency, with transmittance reaching 99.8 % at 600 nm. However, higher porosity minimized mechanical stability, with abrasion resistance decreasing as Pluronic® concentration increased. Prolonged (1 h) thermal treatments at 500 °C led to excessive burnout of the Pluronic®, reducing mechanical resistance. Modifying the silicon precursor ratio (TEOS:MTES) impacts coating density, while both silicon precursor ratio and Pluronic® concentration influence the coatings’ environmental durability. These findings highlight the importance of achieving a balance between optical performance and mechanical/environmental durability. Optimal balanced performance was achieved with 2 % v/v Pluronic® and TEOS:MTES ratio of 70:30. By carefully controlling the formulation and processing parameters, AR coatings properties can be tailored for solar applications, ensuring high efficiency and stability under operational conditions.