Their discovery focuses on a phenomenon called “singlet fission”, which produces two triplet states from an excited singlet state of a molecule.
The researchers used a molecule called 1,3-diphenylisobenzofuran (DPIBF), and their experiments created two triplets of the molecule with a 200% quantum yield, at low temperatures.
The singlet fission works like this: a light-absorbing molecular chromophore (the molecule responsible for the material’s color) shares its energy with a non-excited molecule in its vicinity. This leads to a triplet excited state of each molecule. Two electron-hole pairs are thus generated for each absorbed photon, provided the two triplets behave independently.
This phenomenon had been known for thirty years, but it was only one material that it acted on (tetracene powder). The new discovery finds that the singlet fission can actually happen in DPIBF, too.
A similar phenomenon had been demonstrated by other scientists, it involved quantum dots, and also displaced two electrons with a single photon.