Broadband antireflective coating stack based on mesoporous silica by acid-catalyzed sol-gel method for concentrated photovoltaic application

• Published in: Solar energy materials and solar cells Vol. 186; pp. 154 - 164
• Main Authors: Agustín-Sáenz, Cecilia, Sánchez-García, José Ángel, Machado, Maider, Brizuela, Marta, Zubillaga, Oihana, Tercjak, Agnieszka
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2018; Elsevier BV
• Subjects: Acid-catalyzed; Acids; Antireflection; Antireflection coatings; Atomic force microscopy; Block copolymers; Broadband; Coatings; Ellipsometry; Evaporation; Irradiance; Microscopy; Multilayers; Optical properties; Photovoltaic cells; Photovoltaics; Porous coating; Self-assembly; Silica; Silica gel; Silicon dioxide; Sol-gel; Sol-gel processes; Solar energy; Sols; Spectrophotometry; Acid-catalyzed; Antireflection; Broadband; Porous coating; Silica; Sol-gel
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2018.06.040

Silica multi-layer stacks have been designed with the aim to provide broadband antireflective (AR) properties for glass components in concentrated photovoltaic (CPV) application. Silica porous coatings were grown by combining acid-catalyzed sol-gel route and evaporation induced self-assembly (EISA) method with four types of organic/inorganic systems. Sols were prepared using tetraethylorthosilicate (TEOS) as inorganic precursor assembled with two di-block copolymers, one tri-block copolymer and one cationic surfactant as organic templates. Optical properties were characterized by ellipsometry and spectrophotometry while the material structure was analyzed by environmental ellipsometric porosimetry (EEP) and atomic force microscopy (AFM). The concentration of inorganic and organic phases was optimized and a broadband AR bi-layer stack was obtained providing a 7.2% (under the reference AM1.5 solar spectral irradiance) increase in transmittance over bare glass in the wavelength range 300–2000 nm when coated on both sides.
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•Broadband AR layer stack has been theoretically adapted to spectral response of MJ cells.•Acid-catalyzed sol-gel / EISA method permitted to fit n and thickness of layers.•Layer with highest porosity was obtained from sol with di-block copolymer Brij58.•Mesoporous and dense layers stack provided 7.2% (300–2000 nm), gain transmittance.