Singlet fission efficiency in tetracene-based organic solar cells.

Singlet exciton fission splits one singlet exciton into two triplet excitons. Using a joint analysis of photocurrent and fluorescence modulation under a magnetic field, we determine that the triplet yield within optimized tetracene organic photovoltaic devices is 153%±5% for a tetracene film thickness of 20 nm. The corresponding internal quantum efficiency is 127%±18%. These results are used to prove the effectiveness of a simplified triplet yield measurement that relies only on the magnetic field modulation of fluorescence. Despite its relatively slow rate of singlet fission, the measured triplet yields confirm that tetracene is presently the best candidate for use with silicon solar cells. [ABSTRACT FROM AUTHOR]