Aza-benzannulated-perylenebisimide-porphyrin dyad as an intensely absorbing donor in bulk-heterojunction organic solar cells

Porphyrins (PORPs) have demonstrated excellent photovoltaic performances in organic solar cells when applied in combination with suitable acceptors in molecular donor–acceptor (D–A) dyads. Perylenebisimides (PBIs) have emerged as important non-fullerene acceptors, and various derivatives of PBIs have been incorporated in D–A motifs as acceptors. In this work, we describe the design and photovoltaic performance of a novel N-benzannulated perylenebisimide-porphyrin dyad and its Zn(II) complex. Single-crystal X-ray diffraction (SCXRD) structures show a non-coplanar arrangement between the individual chromophores in the freebase dyad. The PBI and PORP chromophoric units show head-to-tail intermolecular π–π stacking interactions with a D–A distance of 3.4 Å. Solution-processed bulk heterojunction (BHJ) organic solar cells were fabricated using each of the two synthesized molecules as donors with PC71BM as the acceptor. The power conversion efficiencies (PCEs) for PDPP and Zn-PDPP were 7.25% and 9.10%, respectively, and they possess significant electron and hole mobilities.