Dobreva, PetjaNamwiha, Leonard Etuna2025-09-162025-09-162025http://hdl.handle.net/11070/4122A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Renewable EnergySolar 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 layersenPorous silicaSol-gel methodAnti-reflective coatingRadiative coolingTransmittanceEmissivityNamibiaUniversity of NamibiaThesis