Facile Synthesis of Hydrophobic Thermal Insulation Nano-TiO<sub>2</sub>/ZnO and SnO Coating for Solar Cell

The solar light radiation causes some of the heat to be trapped inside the solar cell that raises the solar cell’s temperature, then reduces the electrical efficiency of the overall system. The thermal radiation from solar light causes overheating on the solar cell surface and degrades its functionality. In this study, the thermal insulation coating has been proposed to prevent interior trapped heat. Different nanocoating systems have been developed using nano-Titanium Dioxide (TiO 2 ) namely T1B2 and T2B2, nano-Zinc Oxide (ZnO) namely Z1B2 and Z2B2 and nano-Tin Oxide (SnO) namely S1B2 and S2B2. All the nanoparticles have been synthesized at various weight percentages which are 20wt.% and 60wt.% in the B2 binder system, Methyltrimethoxysilane (MTMS) / nitric acid (HNO 3 ). The incorporation of nanoparticles increases the hydrophobicity of binder coating in which the Water Contact Angle (WCA) of coating improves up to 105°. The embedded nanoparticles increase the surface roughness, then reduce the contact of water to the substrate’s surface. Apart from that, the coating is also capable to halt the drastic increment in surface temperature. The result has shown that the B2 binder coating increases the surface temperature of solar cell by 2.54°C after 1hr of Xe 1000 W/m 2 irradiation. The raise in temperature is due to the strong oxidation of nitric acid. However, the incorporation of nano-ZnO and nano-SnO in B2 binder matrix capable to reduce the temperature of the solar cell. The wide bandgap of both nanoparticles induces good stability of coating at high operating temperature. The Z1B2 and S2B2 has reduced the temperature of solar cell by 7°C and 3°C, indicating their great thermal insulation property for solar cell application.