Z-Shaped Fused-Chrysene Electron Acceptors for Organic Photovoltaics

A new fused-chrysene electron-donating core is synthesized, where chrysene is condensed with two thiophenes via two dihydrobenzene rings. Based on this building block coupled with two electron-accepting end groups of 1,1-dicyanomethylene-3-indanone, a new Z-shaped fused-ring electron acceptor, FCIC, is designed and synthesized. FCIC shows intense absorption in the 500-850 nm region, with a maximum molar absorptivity of 1.5 x 10(5) M-1 cm(-1), a bandgap of 1.50 eV, and a charge mobility of 2.5 x 10(-4) cm(2) V-1 s(-1). The ternary organic photovoltaic cells based on PTB7-Th/F8IC/FCIC yield an efficiency of 12.6%, higher than that of the binary cells of PTB7-Th/F8IC (10.7%) and PTB7-Th/FCIC (7.21%). Relative to the PTB7-Th/F8IC binary blend, the addition of FCIC leads to improvement in the open-circuit voltage, short-circuit current, and fill factor.