Scalable deposition of sol–gel based monolayer antireflective thin films by using a dual alkoxysilane precursor chemistry

In this study, we investigate the prospect of using dual alkoxysilane precursor chemistry for the scalable deposition of antireflection thin films on soda lime silicate glass. The hybrid chemistry involves the use of tetraethyl orthosilicate (TEOS) in combination with methyltriethoxysilane (MTES). Throughout the study, we use a dual acidic catalyst system comprising an organic (acetic acid) and an inorganic (nitric acid) acid. After the coating process, the coated glasses are cured at 100 °C and then annealed at 700 °C to mimic a typical industrial tempering process. The effects of altering the MTES/TEOS mole ratio on the resulting colloidal sol are studied with five different sols using Fourier Transform Infrared (FTIR) analysis and the final properties of solid thin films are investigated in detail through optical spectrophotometry, contact angle measurements, optical microscopy and electron microscopy (Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)) techniques. In addition to the coated glasses, we investigate the thermal stability of dried gels at room conditions as well as at 100 °C, 400 °C, and 700 °C annealing temperatures. Since the PV panel glasses are typically deployed to stay in contact with the external environment, the weathering durability of the samples having optimum properties are investigated in accordance with EN 1096-2 and IEC 61215 standard test methods. It is shown that the presented dual precursor chemistry can produce coatings that exhibit high mechanical and chemical resistance and retain their anti-reflective properties when treated with an industrial tempering process. Finally, we provide evidence that laboratory scale dip coating process can be directly scaled up to a roller coating process without compromising optical performance. Our results show that commercial solar module dimensions and patterned glasses can be directly accommodated with the proposed coating chemistry. Sample preparation process flow chart and contact angle measurements of coated samples which were cured at 100 °C and then annealed at 700 °C using S0.3, S0.6, S1.2, S2.4, and S4.8 solutions with different time intervals. Highlights Highly durable monolayer anti-reflective (AR) coatings that can be annealed with an industrial tempering process up to 700 o C are demonstrated. Using a dual precursor chemistry based on tetraethyl orthosilicate (TEOS) and methyltriethoxysilane (MTES) highly durable AR coatings are obtain