Simulation of anti-reflective TiO2/SiO2 coating for silicon photovoltaic application by ray tracing / Imran Al-Haqeem Jaffar

In solar systems, anti-reflective coatings are used to reduce reflection and increase efficiency. However, the front surface on the solar cells alone is not effective because most of the light from the sun is reflected and very less energy absorption into the solar cells occur. An anti-reflective coating (ARC) of a sufficient thickness can greatly reduce front surface reflectance. Nanoscale surface texturing, on the other hand, can efficiently capture a higher ratio of incident light to boost optical absorption. In this study, the light trapping scheme within the wavelength of 300nm to 1200nm is used to improve the overall efficiency of silicon solar cells. A thin layer of TiO2 and SiO2 anti-reflective coating with different thicknesses is stacked alternatingly due to their different refractive index with TiO2 having a high refractive index and SiO2 with a low refractive index. Solar irradiance spectrum AM1.5G is used in this simulation according to the ASTM standard. For the ray-tracing simulation, the front planar with multilayer ARC with different thicknesses are investigated to obtain the optimum value for optical properties and current density. All the four combination arrangements of SiO2 and TiO2 were studied and from the data obtained, the value of Jmax is calculated. The Jmax value of c-Si (without ARC) is only at 24.93mA/cm2 but when ARC was used on the front surface, the value of Jmax increased to 30.28mA/cm2. This represents an increasement of 21.46% enhancement compared to the Jmax of the c-Si reference.