Top-to-bottom optimization of the optical performance of the tandem organic solar cells with thin metal film as interlayer

Top-to-bottom optimization is developed to maximize the absorption for tandem organic solar cells with thin Ag interlayer connecting two subcells. By redshifting the cavity modes of the microcavity between the Ag interlayer and the top electrode, the absorption spectrum of the top cell can be shifted to the near-infrared wavelength range where the bottom cell has weak absorption. Correspondingly, subcells with highly complementary absorption spectrum are achieved, and there is an improvement of 17.8% in the total absorbed photons for the tandem device. Additionally, it is revealed that high transparency is not an essential property for the interlayer in tandem devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3692597]