Multiple effects of aromatic substituents on excited-state properties and singlet fission process in azaquinodimethane systems.

Singlet fission (SF) could offset the thermalization loss of high-energy photons multiexciton generations, thus holding great potential in improving the power conversion efficiency of solar cells. However, the development of SF-based devices has basically remained stagnant so far owing to the limited scope of practical SF materials. Therefore, designing and developing practical SF material systems have been imperative, yet challenging so far.