Macromolecules, Vol.46, No.1, 113-118, 2013
A Novel Benzo[1,2-b:4,5-b']dithiophene-Based Conjugated Polymer with a Pendant Diketopyrrolopyrrole Unit for High-Performance Solar Cells
A novel conjugated polymer of PBDT-TDPP-S was synthesized, which contains a donor unit of benzo[1,2-b:4,5-b']dithiophene in main chain and an acceptor unit of diketopyrrolopyrrole in side chain. This kind of side-chain donor-acceptor (D-A) polymer exhibited better solution processability, lower HOMO level (-5.34 eV), and more balanced carrier mobility relative to its corresponding main-chain D-A conjugated polymers. Using PBDT-TDPP-S as electron donor and [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as electron acceptor, the resulting polymer solar cells exhibited outstanding photovoltaic properties with a power conversion efficiency of 4.89%, an open-circuit voltage of 0.84 V, a short-circuit current of 10.04 mA cm(-2), and a fill factor of 56.0%.