At the Photovoltaic Technology Evaluation Center (PV-TEC) of the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, researchers have reached efficiencies of up to 20.2% for back-contact silicon solar cells. For the so-called MWT-PERC solar cells, two different approaches for increasing efficiency were applied, including screen-printed aluminum back-contact being connected to the p-type silicon material using local laser alloying.
“We are very pleased to present these excellent results upon the fifth anniversary of PV-TEC. The results demonstrate that silicon photovoltaics is still in the steep part of the learning curve,” says Dr. Daniel Biro, project leader.
The PV-TEC team also achieved efficiencies of 20.0% for Back-Contact Back-Junction (BC-BJ) solar cells based on n-type monocrystalline float-zone silicon material. For this solar cell concept, both the metallization with Al-alloyed emitter as well as the structuring steps are carried out exclusively with screen-printing technology.