Microcavity tandem solar cells with a short circuit current higher than single cells

Abstract We demonstrate by numerical simulation that microcavity tandem organic photovoltaic cells (OPVs) with a capping layer can have a higher short circuit current ( J sc ) than normal ITO based tandem OPVs without the microcavity structure and corresponding single cells. A microcavity tandem OPV consists of SubPc–C 60 and PbPc–C 60 donor–acceptor pairs of each subcell. Two reflecting electrodes, spacer layers, and a capping layer in the microcavity structure control the optical electric field of the device so that J sc in the tandem OPV becomes higher than the normal cells even in its thinner active layers. The optimized microcavity device leads to a 25% increase in J sc compared with the conventional ITO-based device employing the same donor–acceptor pair, and a 5% increase in J sc compared with conventional ITO-based single cells.