Synthesis and photovoltaic properties of benzo[1,2-b:3,4-b′]thiophene-based conjugated copolymers with a pendent acceptor

Abstract

Two novel benzo[1,2-b:3,4-b′]thiophene-based copolymers (namely, PBDT-TPABTBn and PBDT-BTCz) with a pendent acceptor were synthesized through Pd-catalyzed Stille coupling reactions for use in organic photovoltaic devices. To study the photovoltaic properties of the resulting copolymers, polymer solar cells were fabricated with the copolymers as electron donors and [6,6]-phenyl-C71-butyric acid methyl ester as an electron acceptor. The obtained devices based on PBDT-TPABTBn and PBDT-BTCz exhibited power conversion efficiencies of 1.62 % (V oc = 0.94 V, J sc = 4.74 mA cm−2, FF = 0.39) and 0.95 % (V oc = 0.64 V, J sc = 4.16 mA cm−2, FF = 0.36), respectively. Results indicated that the two copolymers were the promising donor candidates for polymer solar cell applications.