Chrysene-Based Azahelicene π-Linker of D-π-D-Type Hole-Transporting Materials for Perovskite Solar Cells.

Chrysene is a readily available material for exploring new polycyclic aromatic hydrocarbons (PAHs). In this study, two chrysene based azahelicenes, nine-membered BA7 and ten-membered DA6, are constructed by intermolecular oxidative annulation of 6-aminochrysene and intramolecular annulation of N6 ,N12 -bis(1-chloronaphthalen-2-yl)chrysene-6,12-diamine, respectively. The hexylated BA7 and DA6 and their brominated products were undoubtedly characterized by single crystal XRD. Subsequent amination with bis(9-methyl-9H-carbazol-3-yl)amine (BMCA) electron donor afforded D-π-D-type semiconductors BA7-BMCA and DA6-BMCA with beneficial properties to act as hole transport materials for perovskite solar cell. Compared with 19.4 % champion power conversion efficiency (PCE) of BA7-BMCA based device, a higher PCE of 20.2 % for DA6-BMCA counterpart may be attributed to its S-shaped double helicene-like linker with extended π-conjugated system.