Conjugated copolymers of triazoloquinoxaline-alt-fluorene with imine chain bridge for photovoltaic solar cells

• A kind of two-dimensional (2D) fluorene derivates first were developed.
• A series of polymers based on N-(aryl)-9H-fluoren-9-imine were synthesized.
• The photovoltaic properties of polymers were studied.

A series of copolymers based on triazoloquinoxaline and fluorene derivatives have been synthesized by Suzuki polycondensation, which have aryl imine chain bridge in fluorene unit. N-(aryl)−9H-fluoren-9-imine was first synthesized and used to construct conjugated polymers, which were applied in organic photovoltaics. The thermal, electrochemical, and photovoltaic properties were characterized. These good solution-processable copolymers showed broad absorption from 350 nm to 800 nm region with the optical bandgap of ~1.55 eV. Preliminary bulk heterojunction solar cells of P3:PC61BM (1:2 w/w) exhibited maximum power conversion efficiency of 1.56% with Jsc of 4.50 mA cm−2, Voc of 0.79 V, and FF of 0.44.