Side-Chain Engineering of Non-Fullerene Acceptors with Trialkylsilyloxy Groups for Enhanced Photovoltaic Performance^†

Side-chain engineering has emerged as a highly effective strategy for tailoring the aggregation behavior and charge transport properties of non-fullerene small molecule acceptors (SMAs). In this study, we designed and synthesized two SMAs, namely BTPSi-Bu and BTPSi-Pr, respectively incorporating tributylsilyloxy and triisopropylsilyloxy groups in their outer positions. Notably, BTPSi-Bu exhibited better planarity, crystallization, and favorable phase separation when paired with PM6 donor polymer compared to its counterpart, BTPSi-Pr. The resulting organic solar cells, utilizing the PM6:BTPSi-Bu blend, demonstrated a remarkable power conversion efficiency of 17.41% and a high open-circuit voltage of 0.859 V. These findings underscore the significance of integrating trialkylsilyloxy side chains into SMAs as a rational design approach for enhancing the performance of photovoltaic systems.