Solar cells with two sides are better than those with one, and bifacial solar cells composed of two materials touted for their photovoltaic performance are better still. An international research team designed bifacial tandem cells composed of both silicon and perovskite, which exceed currently accepted performance limits for tandem configurations.

Higher energy conversion efficiencies were demonstrated for the new cells relative to monofacial A bifacial perovskite/silicon tandem prototype being field-tested. Source: Michele De Bastiani/King Abdullah University of Science and Technologyperovskite/tandem designs as the bifacial structure can collect and harness albedo, or light reflected and scattered from the ground. Power conversion efficiencies greater than 25% were documented under monofacial AM1.5G 1 sun illumination, and power generation densities recorded during outdoor tests were as high as 26 mW/cm2.

“By exploiting the albedo, we can now generate currents higher than in conventional tandems, without increasing the manufacturing costs at all,” said Dr. Michele De Bastiani, a lead researcher from King Abdullah University of Science and Technology, Saudi Arabia.

Scientists from the University of Toronto, Karlsruhe Institute of Technology (Germany) and University of Bologna (Italy) also contributed to this development.