Jolywood and Imec Achieve Record 23.2% with Bifacial n-PERT Solar Cells

The result was certified by the solar cells laboratory at the calibration and test center of Germany’s Institute for Solar Energy Research.

Belgian micro and nano-electronic research center Imec, has announced that its n-PERT (Passivated Emitter and Rear Totally diffused) solar cells developed with Chinese bifacial solar panel maker Jolywood have reached a certified and record front-side conversion efficiency of 23.2 percent.

“Compared to the previous results imec reported, we have further optimised the fully screen-printed bifacial n-PERT cell process and adopted design with twelve busbars. The current cells also have a screen-printed front grid and rear soldering pads that use less silver,” says Loic Tous, project leader at imec/EnergyVille.

“The open circuit voltage is now above 690mV with fill factors up to 83%. These remarkable results are obtained using the same industry-compatible equipment to produce bifacial p-PERC cells, with the addition of boron diffusion.”

A batch of 12 new M2-sized cells (244.3 cm²) measured at Germany’s Institute for Solar Energy Research (ISFH) CalTec showed an average conversion efficiency of 23.0 percent, with the best cell topping 23.2 percent. While the research centres own measurements revealed a bifaciality above 80 percent.

The developed n-PERT technology has a number of inherent advantages over p-type PERC cell technology, which is demonstrated in these newest cells: the potential for higher efficiencies because of lower sensitivity to metal impurities, and the absence of light-induced degradation (LID). Therefore, n-type PERT technology could become a cost-effective contender to p-type PERC cells. To enable this, the current cells have a screen-printed front grid and rear soldering pads which together amounts to less than 80mg of silver used per cell. 

Jia Chen, R&D director at Jolywood said, “Jolywood targets to bring the best solar solution to the market. Devoted to R&D and manufacturing of the world’s best n-type cells and modules, we believe n-type technology can contribute to the industry with high performance, high reliability, and low LCOE. We have chosen imec to help us reach that target because of their unique expertise and research infrastructure. We are also developing bifacial n-PERT cells with passivating contact technology, and have already achieved efficiencies above 23%. Combining all the technical know-how, we are confident that our bifacial n-type solar cells will achieve an efficiency above 24% very soon.”

Imec and Jolywood are confident that their bifacial n-PERT cells will soon reach efficiencies above 23.5 percent, coupled to a bifaciality above 90 percent.