High-performance polymer heterojunction solar cells of a polysilafluorene derivative

High-performance polymer heterojunction solar cells fabricated from an alternating copolymer of 2,7-silafluorene (SiF) and 4,7-di(2′-thienyl)-2,1,3-benzothiadiazole (DBT) (PSiF-DBT) as the electron donor blended with 6,6-phenyl-C61-butyric acid methyl ester as the electron acceptor were investigated. A power-conversion efficiency up to 5.4% with an open-circuit voltage of 0.90V, a short-circuit current of 9.5mAcm−2, and a fill factor of 50.7% was achieved under the illumination of AM 1.5G from a calibrated solar simulator (800Wm−2). The field-effect transistors fabricated from PSiF-DBT showed a high hole mobility of ∼1×10−3cm2V−1s−1.