Silver Paste with Nano-sized Glass Frits for Silicon Solar Cells

Scientists are looking for alternatives to fossil fuels as energy source in order to reduce the environmental issues. Solar energy is one of the candidates that have attracted our attention. Monocrystalline and polycrystalline silicon materials are the most common ones for solar cell panels, and one of the key properties of silicon solar cells is the interfacial resistivity between the front silver electrodes and the n-type silicon emitters. The interfacial resistivity is hugely affected by the interfacial structure between silver electrodes and n-type silicon emitters, which plays a very substantial role for the electrical and mechanical properties of the fabricated silicon solar cells. Previous studies show that the residual glass frits layers at the Ag/Si interfaces after the firing process will dramatically increase the contact resistance and this phenomenon subsequently leads to degradation in the overall efficiency of the silicon solar cells. In this study, nano-sized glass frits were employed to improve the interfacial conductivity. Transfer length method (TLM) was applied to evaluate the electrical performance of samples made by different glass frits. Because of the excellent etching ability of nano-sized glass frits, the total amount of isolating compositions can be reduced and therefore there is less residual ceramic at the interfaces. For samples made with nano-sized glass frits, the specific contact resistivity was found to be only 40% of that of samples made with micro-sized glass frits after otherwise identical processing. Our results show that nano-sized glass frits can provide better energy efficiency, less processing time and lower manufacturing cost.