Enhanced charge separation by interchain hole delocalization in nonfullerene acceptor‐based bulk heterojunction materials

Bulk heterojunction (BHJ) composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods. A reduced carrier recombination loss an BHJ was characterized previously. However, the driving force that leads to this reduction not clearly understood. In study, we focus on decreased and its nonfullerene acceptor-based PTB7-Th:IEICO-4F composites. We demonstrate shows deactivation sub-nanosecond nongeminate process. The for determined be interchain hole delocalization between polymers. An enhanced observed steady-state photoinduced absorption (PIA) spectroscopy. particular, increased splitting polaron PIA bands noted. Moreover, other state-of-the-art materials, including D18:Y6 with morphologies.