Highly transparent singlet fission solar cell with multistacked thin metal contacts for tandem applications

Singlet fission solar cells combined with silicon photovoltaics allow the construction of parallel tandem solar cells, which benefit from better usage of high-energy photons. A key limiting factor for the performance of such a tandem configuration is the transparency of the singlet fission front cell. Here we show highly transparent singlet fission solar cells with a top contact of thin Ca:Ag blends. The optimized contact leads to 81% average solar cell transmittance in the near-infrared while maintaining more than half the short-circuit current density compared with an opaque device. We simulate the performance of the parallel tandem stack and assess the improvements needed to fully realize the potential of singlet fission in this device configuration.