Síntese e caracterização de xerogéis aílica/orgânico dopados com cério visando a aplicação como filtro UV para painéis fotovoltaicos

Abstract

Photovoltaic technology is the most promising for global energy transition, seeking to reduce the consumption of fossil fuels by replacing them with renewable and low cost environmental sources. Generally, a photovoltaic panel comprises a set of silicon cells responsible for converting solar radiation into electrical energy, covered by a glass plate for the mechanical protection of the system. The junction between the cells and the cover glass is made by a polymeric encapsulant, with Ethylene Vinyl Acetate (EVA) being the most used. These materials are fundamental because they chemically and mechanically protect the delicate silicon cells. However, the most used encapsulating polymers undergo a degradation process induced by ultraviolet radiation, which significantly challenges extending the panels' lifespan. Applying films or coating material with UV radiation blocking properties can be a promising alternative to overcome this issue. In this sense, organic inorganic hybrid materials have gained significant prominence due to their optimized properties from combining the constituent phases' properties, such as flexibility, low density, thermal and chemical stability, mechanical resistance, high transparency, and ease of production of thin films. This work proposes synthesizing and characterizing silica organic xerogel monoliths with high optical quality doped with cerium. The xerogels were prepared based on Tetraethylorthosilicate (TEOS) and 3 Glycidoxypropyltrimethoxysilane (GPTS) via the sol gel process. X ray diffraction, thermal analysis, and infrared spectroscopy characterization reveal an amorphous and stable hybrid structure depending on the dopant concentration, reaching up to 1% by mass. The undoped matrix presents a wide transmission window and adding cerium results in a redshift of the cutoff edge from around 300 to 410 nm and a slight reduction in reflectance. Furthermore, all samples exhibit suitable refractive index values, combined with the EVA encapsulant, which minimizes losses due to the reflection of the radiation above 410nm transmitted. These results point to the GPTS/TEOS system doped with cerium as a promising candidate for UV filter coating in photovoltaic panels.