Nano-glass frit for inkjet printed front side metallization of silicon solar cells prepared by sol-gel process

Sol-gel derived nano-sized glass frits were incorporated into the Ag conductive ink for silicon solar cell metallization. This mixture was specifically formulated for inkjet printing on textured Si wafers with 80 nm thick SiN_x anti reflection coating layers. The correlation between the contact resistance and interface microstructures were studied using scanning electron microscopy and transmission electron microscopy. In addition, the specific contact resistance between the front contact and emitter was measured at various firing conditions using the transfer length model. On an emitter with the sheet resistance of 60 Ω/sq, a specific contact resistance below 5 mΩ cm² could be achieved at a peak firing temperature around 800 °C. We found that the incorporated nano-glass frit act as a very effective fire through agent, and an abundant amount of Ag crystallites was observed along the interface glass layer.