Laser transfer printing forms high-aspect-ratio fingers using 10 μm thick films, helping reduce shading and improve current collection
Solamet reported efficiency gains of around 0.13% absolute, driven by improvements in current density, Voc and fill factor
Remaining challenges include micro-break detection, finger peeling, and paste splattering during high-power laser processing
As metallization pathways continue to evolve beyond conventional screen and stencil printing, laser-assisted approaches are attracting attention as another route to fine-line metallization. By enabling high-aspect-ratio metallization with reduced shading losses, these techniques offer additional opportunities for incremental efficiency improvements.
At the TaiyangNews Solar Technology Conference.India 2026, Daniel Lim, Senior Technical Engineer at Solamet, discussed the latest developments in laser transfer printing, highlighting its potential to improve current collection while enabling finer metallization patterns.
As part of the solutions for fine-line printing, Solamet’s Lim also discussed laser transfer printing. By transferring 10 μm thick films, the technique enables well-defined finger geometries with high aspect ratios. On the performance front, it supports reduced shading and improved current collection, reflected in an efficiency gain of around 0.13% absolute, attributable to an increased current density of about 0.28 mA/cm², a slightly higher Voc of 3 mV, and a modest gain in fill factor.
At the same time, the technology is still undergoing optimization. Key challenges include paste handling during transfer, where idle time on the film can affect film release and lead to broken fingers, which has been resolved, according to Lim. Issues still under optimization include micro-breaks of 50 μm that are difficult to detect during visual inspection. The higher aspect ratio of the fingers also introduces the risk of finger peeling during downstream post-firing processes. In addition, achieving finer trench dimensions requires higher laser power, which can lead to paste splattering and negatively impact current collection.
The table below compares the current capabilities and future development targets of the major fine-line printing technologies.
The roadmap for fine-line printing continues to focus on reducing both opening dimensions and finger widths. Conventional screen printing currently operates with openings of 8-11 μm and finger widths of 15-19 μm, with future targets of 6-9 μm and 13-17 μm, respectively. Despite ongoing improvements, screen printing remains limited by paste spreading and screen stability at very fine dimensions.
Stencil printing offers a more advanced pathway for fine-line metallization. Current stencil processes achieve openings of 6-11 μm and finger widths of 12-15 μm, with development targets of 4-6 μm for openings and 9-11 μm for finger widths. The technology benefits from improved paste transfer and higher aspect ratios compared to conventional screen printing.
Laser transfer printing currently enables openings of 8-10 μm and finger widths of 10-12 μm, already among the narrowest in production-oriented approaches. Future targets aim for openings of 6-8 μm and finger widths of 7-10 μm. These dimensions highlight the technology’s potential to support further silver reduction and efficiency improvements through reduced shading and improved current collection.
The text is an edited excerpt from TaiyangNews’ report on Cell & Module Technology Trends 2026, which can be downloaded for free here.