Researchers across Europe have developed a graphene solar cell with perovskite materials to get a record 26.3 per cent efficiency
The team with researchers at the University of Rome Tor Vergata, the Italian Institute of Technology (IIT) and its spin-off, Graphene Flagship Associate Member BeDimensional, in cooperation with ENEA, successfully combined graphene with tandem perovskite-silicon solar cells to achieve the efficiencies. Using graphene lends itself to a new manufacturing method that could reduce the production cost of large-area solar panels.
The maximum efficiency of silicon solar cells to 32 per cent, and recent perokskite cells have topped 25 per cent. However, the latter present several manufacturing challenges, although they can be ink-jet printed across large areas. Tandem cells combine the advantages of silicon with a layer of perovskite on top for higher efficiency but with more complex manufacturing: Oxford PV kits out German tandem cell production line.
Last week imec showed a perovskite cell with efficiency of 26 per cent that for the first time could take on silicon cells at Thin film cell takes on mainstream solar panels.
Taking the efficiency even higher, the mechanically stacked two-terminal perovskite/silicon tandem solar cell design from the Graphene Flagship has the sub-cells independently fabricated and optimised. These sub-cells are then coupled by contacting the back electrode of the perovskite top cell with the texturized and metalized front contact of the silicon bottom cell. The optical losses that come from stacking the cells are reduces by engineering the hole selective layer/rear contact structure, and using a graphene-doped layer for the perovskite top cell. This device demonstrates a 26.3% efficiency (25.9% stabilized) over an active area of 1.43 cm2.
"Our new approach to manufacture graphene-enabled tandem solar cells provides a double advantage. First, it can be applied to enhance all the different types of perovskite solar cells currently available, including those processed at high temperatures," said said Aldo di Carlo, researcher in Graphene Flagship partner University of Rome Tor Vergata.