Robust Singlet Fission in Disordered Thin Films of a Tethered Dipyrrolonaphthyridinedione Cyclophane-Like Skeleton.

The practical applications of singlet fission (SF) are currently restricted by the limited number of SF-active materials and the stringent requirement of intermolecular interactions. It is still imperative but challenging work to develop an efficient SF system weakly dependent on molecular orientation and film morphology. Here, we elaborately designed a tethered cyclophane-like skeleton and constructed a disordered aggregation system. Based on the comprehensive structural analyses and spectroscopic characterizations, we clearly demonstrated that efficient SF and triplet separation processes could still happen in these disordered amorphous films without a typical long-range π-π stacking arrangement. The results imply that long-range ordered molecular packing and highly oriented crystalline domains are no longer indispensable prerequisites for achieving an efficient SF process. These outcomes would open up a new avenue for the implementation of high-performance SF-based photovoltaic devices.