Tandem cell is an effective strategy to obtain high efficiency organic solar cells (OSCs)

which could address the issues of the absorption limitation and thermalization loss of single junction OSCs. Recently

a tandem cell with a breakthrough power conversion efficiency of 17.3% was reported

in which two subcells with efficient

complementary absorptions were used. The results demonstrate that OSC would achieve comparable efficiency in contrast to other photovoltaic cells through suitable materials design and device optimization in future.