Does Singlet Fission Enhance the Performance of Organic Solar Cells?

Singlet fission, in which the optical spin-singlet exciton dissociates into two low energy triplet excitons, has been proposed as a viable approach to enhance the quantum efficiency of organic solar cells. We show that even when singlet fission is occurring in the donor molecule, the electronic structure at the donor–acceptor interface must satisfy specific requirements for the solar cell performance to be enhanced by this process. We focus on the pentacene–C 60 solar cell, and on the basis of our calculations and available experimental data, we conclude that there is not enough evidence that these requirements are met by the donor–acceptor interface here. We propose experiments that can determine whether the minimal requirement for enhanced performance driven by singlet fission is met in this and other solar cells.