Enhanced photocurrent and open-circuit voltage in a 3-layer cascade organic solar cell

We demonstrate a cascade architecture for organic solar cells with two planar donor/acceptor (DA) heterojunctions operating in series. In a 3-layered structure, subphthalocyanine (SubPc) acts as an ambipolar interlayer between a tetracene (Tc) donor and a C-60 acceptor. The Tc/SubPc and SubPc/C-60 interfaces are both able to contribute to the photocurrent, which results in a short-circuit current in the 3-layer cascade cell larger than in any of the constituent bi-layer DA combinations. Furthermore, the open-circuit voltage is increased due to reduced recombination losses at the DA interface. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757575]