The Link between Ag-Paste Rheology and Screen Printed Solar Cell Metallization

Today’s PV production chain is moving into a material crisis as the use of silver for front-side metallization of PERC solar cells remains a crucial requirement. The shared effort of the scien-tific and industrial community to further reduce Ag-consumption as much as possible without compromising cell efficiency has become more challenging in recent years. Further improve-ments require a deep understanding on the paste-screen interaction at narrow line widths. This study presents the impact of Ag-paste rheology on fine line screen printing for screen openings between 15 μm and 24 μm at industrial printing speeds of up to 600 mm/s. A clear trade-off be-tween maintaining a sufficient reproducibility of the screen printing process and achieving an optimized printed Ag-electrode geometry, thus optimal Ag-consumption emerges. Further, a cor-relation between the work of adhesion at the paste-wire interface within the screen and the result-ing deviation of the printed electrode height has been discovered, highlighting the importance of an advanced screen optimization for the future of fine line screen printing. Finally, we present an easy to use method for analyzing the reproducibility of printed Ag-electrode geometries even for lab-scale data sets.