Optical Simulation of Tandem Organic Solar Cells with Microcavity structures

Abstract

We demonstrate by numerical simulation that microcavity tandem organic solar cells (OSCs) with a capping layer can have a higher short circuit current density (Jsc) than normal ITO based tandem OSCs without the microcavity structure and corresponding single cells. The microcavity tandem OSCs consist of SubPc-C60 and PbPc-C60 donor-acceptor pairs of each subcell. Two reflecting electrodes, spacer layers, and a capping layer with the microcavity structures control the optical electric field of the device so that Jsc in the tandem OSC becomes higher than the normal cells even with its thinner active layers. The optimized microcavity device leads to a 33 % increase in Jsc compared with the conventional ITO-based OSCs employing the same donor-acceptor pair, and a 10 % increase in Jsc compared with ITO-based single cells.