Synthesis and characterization of hydrophobic silica nano particles as anti-reflective coating for photovoltaic

Abstract

Enhancing the power conversion efficiency is an essential research subject in the manufacturing industry of photovoltaic (PV) devices which makes these devices more cost-competitive as compared to traditional energy sources. The revolutionary impact on the performance and efficiency of many optical systems and components come from the integrative design of multifunctional coatings which must be mechanically robust, efficient and a combination of required optical functions with scalable fabrication formulations. In numerous optical systems, suppression of light reflection from surfaces is a critical consideration to enhance their performance. Various designs of antireflective (AR) coatings are implemented extensively in a wide variety of optical systems to enhance the efficiency and power output . In photovoltaic devices, nano coatings are used on glass to make hydrophobic and anti-reflective coating. The rough surface and low-wetting properties of hydrophobic coating make it easier to clean the glass especially under extreme weather conditions such as pollution, rain and dust or sands. The present project proposed deposition of anti-reflection hydrophobic coating base on silica nanoparticles. The silica nanoparticles are prepared and modified using dimethyldichlorosilane (DMDCS) to enhance the surface roughness in nano-size range 60 - 90 nm. The spin-coating technique at room temperature is employed to deposit modified silica hydrophobic thin film. The deposited thin films are annealed at different temperatures (100°C, 200°C, 300°C and 400°C) for 3 hours. The deposited thin films are subjected to rain droplet and roll off simulator’s performance test measurements. Field emission scanning electron microscope topographic image shows that the morphology of silica nanoparticle is rougher when it functionalized with organosilane. The water contact angle measurement shows a higher contact angle 94.45° and the lowest roll off angle 12.93° is observed for a thin film annealed at 300°C . The thin film apparently looked clean and transparent after subjected to the rain droplet simulator. Furthermore, the optical analysis revealed that all deposited thin films have no significance change of transmittance and reflectance before and after the performance test which indicate that the coatings are durable and possess hydrophobic and antireflective characteristics.