Browsing by Author "Namwiha, Leonard Etuna"

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    Enhancing solar photovoltaic efficiency with porous silica coatings
    (University of Namibia, 2025) Namwiha, Leonard Etuna; Dobreva, Petja
    Solar surface glass is known to exhibit reflectance loss of no less than 4%, depending on the angle of the incident light. Furthermore, the high operating temperature of the solar photovoltaic (PV) module also reduces the solar PV module efficiency by approximately 0.45 − 0.50 %/℃ depending on the temperature coefficient and the type of the solar modules[1]. The study investigated porous silica which is known to have high transmittance in the solar spectrum range (0.3-1.1μm) and high emissivity in the mid-infrared range (8-13μm) due to its bonding structure. The research employed the base/acid double catalysis technique of the sol-gel method, using Pluronic F127 as a surfactant, Tetraethylorthoxysilicate (TEOS), ethanol, hydrochloric acid, ammonium hydroxide, hexamethyldisilazane (HMDS) and distilled water to synthesise silicon dioxide sol. The sol was afterwards spin-coated on a glass substrate, resulting in a porous silica layer approximately 200 nm thick. Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Ultraviolet-Visible-Near Infrared Spectroscopy (UV-Vis-NIR) spectrophotometer were employed to investigate the optical characteristics of the coatings. The study achieved an approximate 2% increase in transmittance within the solar spectrum (0.3- 1.1μm) with a single porous silica layer with 8% emissivity in the mid-infrared range (8-13μm). In addition, it observed a nearly 20% enhancement in emissivity with three layers in the mid-infrared range (8-13μm), while transmittance in the solar spectrum (0.3-1.1μm) decreased almost linearly by 8% from 0.3-0.55μm with three layers