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.