Recent paper: Record EQE organic solar cell based on singlet exciton fission

Singlet exciton fission – a process found in special organic semiconductors – splits a high energy singlet state, which is created upon photon absorption, into two, low-energy triplet states of equal energy. Incorporating such organic materials in a photovoltaic cell paves the way to more carriers produced per incident photon flux.

Based on the singlet fission archetype material pentacene, in an exciton confining architecture around a heterojunction with the fullerence acceptor C60, we (Congreve et al., Science 340, 334 (2013)) have demonstrated an external quantum efficiency of an organic solar cell exceeding 100%, breaking the barrier of one electron per photon in the visible spectrum.