IMEC's large area solar cells with 18.4pc conversion efficiency, featuring Cu-plated contacts

LEUVEN, BELGIUM: At the European Photovoltaic Solar Energy Conference, IMEC presented a large-area solar with a conversion efficiency of 18.4 percent.

Compared to the standard i-PERC cell process, IMEC’s solar cell features a shallow emitter and advanced front metallization using copper plating. The results were obtained on large-area cells (125cm2), proving the industrial viability of the process.

The shallow emitter results in an enhanced blue response, and thus in a higher conversion efficiency than with a standard emitter. For the front contacts, a novel metallization stack is added which is applied to local openings in the antireflective coating.

Dr. Joachim John, team manager at IMEC, said: “Using copper instead of silver adds to the sustainability of solar cell production. IMEC was able to do this because it has extensive experience with copper plating on silicon. A similar efficiency result was obtained with screen printed contacts, but the long-term sustainability and low-cost potential of Cu-based contacting solutions and the fact that this was a first result obtained without dedicated fine-tuning makes this result particularly encouraging.”

Dr. Jef Poortmans, IMEC’s Photovoltaics Program Director, stated: “These cells and the new metallization stack involved are a further successful step in IMEC’s target to develop ever more cost-effective, efficient crystalline Si solar cells –- eventually targeting cells that are only 40µm thick with efficiencies above 20 percent.”