One big improvement brought about by this technology is that it limits ultraviolet-induced degradation (UVID120) to less than 1%, addressing a major durability issue faced by high-efficiency solar modules. DAS Solar says it achieved this with a stacked passivation structure applied on front side using atomic layer deposition (ALD), which protects against UV damage, enabling it to keep UVID120 below 0.8%. Another improvement on the front side is that a special trapezoid-shaped busbar, combined with optimized screen-printing techniques and paste formulations, enhances photon collection and raises the fill factor to over 85%.
On the back of the cell, a customized high-performance laser system creates the ‘PolyFinger’ structure (micro-scale features that trap more infrared light), increasing absorption by 0.3% to 0.5%. For improved charge extraction, nanosecond lasers form ultra-small metal contacts with contact resistance under 0.5 mΩ·cm². The technology also involves passivating edge passivation of half cut cells. DAS Solar treats the cell edges with hybrid organic-inorganic passivation layer to reduce edge-recombination losses
Taking TOPCon as its core technology stream, DAS Solar is branching into 3 more advanced technologies. The company says it focuses its R&D on TOPCon while developing proprietary innovations, in line with its ‘One Core, Three Branches’ strategy. The company calls its in-house back-contact architecture as Diamond Back Contact (DBC), while tandem technologies include the proprietary perovskite-silicon platform (TSiP) and silicon-based singlet fission (SFOS).
At SNEC 2024, DAS Solar showcased its DBC modules based on the earlier TOPCon 4.0 Plus platform, featuring efficiencies above 24%. A new generation combining DBC with TOPCon 5.0 is currently under development. In parallel, DAS Solar’s 4-terminal tandem module, developed in partnership with China Three Gorges Group, has reached 25.4% efficiency and entered pilot deployment. Its 2-terminal tandem cell has achieved a laboratory efficiency of 33.5%.
DAS Solar collaborated with institutions like Zhejiang University, Xiamen University, UNSW, and Hebei University, along with equipment and materials partners, to develop TOPCon 5.0.
In the commercial segment, DAS Solar’s TOPCon module is featured in the TaiyangNews TOP SOLAR MODULES listing. The DAS-DH156NA n-type module, built on a 182 mm wafer format, uses 156 half-cells and delivers a power output of 630 W with an efficiency of 22.5%. It is a bifacial glass-glass module with 2 mm glass on both sides and offers up to 80% bifaciality (see TOP SOLAR MODULES Listing – April 2025).
