Front side photovoltaics metallization pastes for high aspect ratio grid lines

For the front side photovoltaics metallization paste, acquiring a high aspect ratio grid line is one of the keys to boosting crystalline silicon solar cell efficiencies. Currently, with screen printing technology, fired grid line width under standard production parameters are commonly in the range of 80-120 μm with about 0.2 aspect ratios. In this paper, we report our most recent efforts and progresses on developing novel types of organic vehicles, which influence the rheological behavior of front side pastes drastically. Along with the optimization of screen and printing parameters, we observed a significant improvement in the high resolution printed line quality. With single pass screen printing, 60-70 μm width with 0.25-0.35 aspect ratio fingers were fabricated, while maintaining excellent lay-down features.