Longi improves efficiency of its heterojunction cell from 25.82 to 26.30% in just one week

Chinese PV module maker Longi claims it was able to improve the efficiency of its heterojunction solar cell based on an M6 wafer from 25.82 to 26.30% in just one week.

The result, which the company says also represents the world’s highest efficiency for a front-back contact (FBC) solar cell, was confirmed, once again, by Germany’s Institute for Solar Energy Research Hamelin (ISFH).

“The fill factor (FF) of the certified cells breached the threshold of 86%, reaching 86.59% and achieving the world’s highest level for silicon cells,” the manufacturer said in a statement. “A new process developed by LONGi’s R&D team can effectively reduce the contact resistance of the interface, so as to improve the FF and increase a cell’s current density.”

The cell also showed a current density of 40.49mA/cm². “The microcrystalline N window layer was optimized to further increase current density, with a new intrinsic layer structure developed to enhance passivation performance and increase the open-circuit voltage up to 2mV,” Longi further explained. “From 25.26% through 25.82% to the latest 26.30%, LONGi has now achieved the rare feat of setting HJT cell efficiency world records three times in six months.”

Longi had announced in July a 25.19% efficiency for p-type TOPCon solar cell and a month earlier a 25.21% efficiency for n-type TOPCon device.