Hot melt ink technology for crystalline silicon solar cells

This paper presents a new thick film system for forming front and rear contacts on crystalline solar cells; the aim is to improve manufacturing throughput, reduce wafer breakage and improve cell efficiency. The Hot Melt ink technology presented differs from conventional thick film because unlike thick film ink that is a liquid at room temperature, the Hot Melt ink is a solid. The solid ink is processed using a resistively heated screen to melt the ink which then allows conventional screening. Once the ink is transferred to the wafer, maintained at approximately 25°C, it instantly resolidifies, traditional drying processes are therefore unnecessary. By eliminating the drying processes, throughput and yield is increased due to reduced substrate handling. The resolidification property of the hot melt ink may be used to reduce line spreading of the front side contact and reduce shadow losses.