ISFH Makes a Key Contribution to a New Record of PERC Efficiency of 21.2%
October 05 06:08:32, 2025
DEK Solar and the Hamelin Institute of Solar Energy (ISFH) have joined forces to push the boundaries of crystalline silicon solar cell performance. Their collaboration focused on enhancing efficiency through the use of screen-printed metal contacts on the back side of the cells, combined with a two-step screen and steel mesh printing process on the front. This innovative approach led to a record-breaking conversion efficiency of 21.2% for PERC (Passivated Emitter and Rear Cell) technology.
Typically, screen-printed solar cells achieve efficiencies between 17.5% and 19.5%. However, this latest breakthrough—leveraging advanced metallization techniques like screen and stencil printing—has set a new benchmark in the industry. The achievement highlights the potential of cost-effective, scalable methods that can significantly boost performance without compromising on production feasibility.
Key technologies from DEK Solar played a crucial role in reaching this milestone. The high-precision Eclipse metallization platform, along with ultra-fine grid wire meshes and precision stencils, contributed to the remarkable 21.2% efficiency. The cells used Heraeus’ optimized front-side silver paste, while the two-step printing process from DEK enabled precise front metallization. First, the main grid was printed using a five-line design from DEK’s Precision Mesh, followed by the fine grid lines—46 micrometers wide—printed via an ultra-fine grid stencil.
The ultra-fine grid stencils from DEK ensure exceptional print uniformity and aspect ratio, even at widths as narrow as 40 micrometers. By precisely controlling the relative heights of the main and fine grids, shading losses are minimized, silver paste usage is reduced, and non-contact main grid pastes can be employed to boost open-circuit voltage (Voc), ultimately enhancing cell efficiency. On the backside, DuPont’s aluminum paste was used for metal contact printing.
“This achievement should not be overlooked,†said Tom Falcon, Chief Engineer at DEK Solar. “The collaboration between ISFH and DEK has delivered a solution that the solar market has been seeking: a cost-effective metallization process using screen and stencil printing to produce highly efficient, industrial-scale PERC cells. This is a major leap forward for the global solar industry.â€
Dr. Thorsten Dullweber, head of the ISFH research group on solar cell production, also emphasized the significance of the improvement: “Achieving such a notable increase in efficiency, especially when using silk screen and stencil printing with less than 80 mg of silver paste per wafer, is no small feat. DEK Solar has been—and will continue to be—an essential partner to ISFH, offering not only cutting-edge equipment and tools, but also deep process expertise.â€