Sol-gel-derived nano-sized double layer anti-reflection coatings (SiO ₂/TiO₂) for low-cost solar cell fabrication

We investigate nano-sized double layer anti-reflection coatings (ARCs) using a TiO₂ and SiO₂ sol- gel solution process for mono-crystalline silicon solar cells. The process can be easily adapted for spraying sol-gel coatings to reduce manufacturing cost. The spray-coated SiO₂/TiO₂ nanosized double layer ARCs were deposited on mono-crystalline silicon solar cells, and they showed good optical properties. The spray coating process is a lower-cost fabrication process for largescale coating than vacuum deposition processes such as PECVD. The measured average optical reflectance (300-1200 nm) was about ∼8% for SiO₂/TiO ₂ nano-sized double layer ARCs. The electrical parameters of a mono-crystalline silicon solar cell and reflection losses show that the SiO ₂/TiO₂ stacks can improve cell efficiency by 0.2% compared to a non-coated mono-crystalline silicon solar cell. In the results, good correlation between theoretical and experimental data was obtained. We expect that the sol-gel spray-coated mono-crystalline silicon solar cells have high potential for low-cost solar cell fabrication.