Imec, through its research partnership with other Belgian institutes EnergyVille, has developed a new process for the screen printing of n-type passivated emitter rear totally diffused (PERT) cells, which it says is ‘industrially compatible’.
According to imec, the cells utilize screen printed silver fingers on the frontside, and aluminum fingers on the rear, which make contact with the emitter, and mean that less costly silver is used in the production. A cell area of 244.4cm² was measured by imec, demonstrating average efficiency of 21.9%, and a peak of 22.1% for the best cell. Imec states that if used as bifacial cells, with an additional 0.15% rear illumination, the cells could achieve effective efficiency of 25%.
“We are very pleased with the bifacial nPERT results obtained in close collaboration with Jolywood. These results fit very well with our roadmap towards 22.5 percent printed bifacial nPERT cells and 23.5 percent monofacial nPERT cells by the end of 2018,” said Loic Tous, project leader at imec. “We are looking forward to continuing our developments with our colleagues at Jolywood and hope to contribute further to their expanding technological portfolio. Jolywood is aiming at developing the world’s best n-type cells and modules and we believe we are uniquely placed to help them reach that target.”
Imec had previously achieved a higher average efficiency of 22.04% on its bifacial n-type PERT cells, a few points were dropped here in developing a process that could easily be applied to industrial production. “The difference is the metallization, screenprinting vs plating,” imec scientist Filip Duerinckx explained to pv magazine. “In addition, these are five busbar cells while the 22.8% were busbar-free cells. Screen printing is currently a much more industrial technique, hence we believe this to be an important result”