Dithienocyclopentadibenzothiophene: a C2v-symmetric core for nonfullerene acceptors with tunable bandgaps

Abstract

The electron-donating core is one of key components in constructing high-performance nonfullerene acceptors for organic solar cells (OSCs). Herein, dithienocyclopentadibenzothiophene (DTCDBT), a C_2v-symmetric core, was for the first time used to design and synthesize efficient nonfullerene acceptors (DBTTC, DBTIC and DBTIC-2F) with various bandgaps in combination with different electron-withdrawing terminal units. When the nonfullerene acceptors were used to fabricate OSCs with a wide-bandgap polymer donor (PBDB-T), the DBTTC-based device exhibited an impressive power conversion efficiency (PCE) of 11.25%. While the DBTIC- and DBTIC-2F-based devices showed lower PCEs of 9.66% and 6.81%, respectively. The results afford a useful rational design strategy as well as a new C_2v-symmetric building block for nonfullerene acceptors which can be used for further advancing the PCEs of photovoltaic devices.