Metal aerosol jet printing for solar cell metallization

Metal aerosol jet printing is a new non‐contact direct‐write technique for the front side metallization of highly efficient industrial silicon solar cells. With this technique the first layer of a two‐layer contact structure is created. It features a low contact resistance and good mechanical adhesion to the silicon surface. The second layer is formed by light‐induced silver plating (LIP) to increase the line conductivity. To form the first layer a metal‐containing aerosol is created in the printer and focused via a second surrounding gas stream through a nozzle and deposited onto the substrate. The focussing gas avoids the contact between the aerosol and the nozzle tip. In addition, line widths significantly smaller than the outlet diameter of the nozzle tip can be reached. Fine and continuous lines with a width of 14 µm were printed using a metal organic ink. As the adhesion of these layers was not sufficient, a commercially available screen‐printing paste for solar cell metallization was modified and tested. Monocrystalline silicon solar cells of 12·5 cm × 12·5 cm with an aluminum back surface field were processed, achieving energy conversion efficiencies up to 17·8%.