Synthesis and photovoltaic properties of a furan-diketopyrrolopyrrole-fluorene terpolymer

• Furan appended diketopyrrolopyrrole and fluorene based polymers were synthesized.
• Their photophysical and electrochemical properties were studied.
• In BHJ solar cell devices these polymers gave PCE up to 1.6%.

We report the synthesis of two solution-processable reduced band gap donor–acceptor conjugated polymers p(C8-DPP-F) and p(C12-DPP-F), composed from 9,9-dioctylfluorene as the donor moiety, diketopyrrolopyrrole (DPP) moiety as the acceptor moiety and furan bridges. Two different alkyl chains, n-dodecyl and n-octyl were used on the DPP moiety and the impact of this structural modification evaluated in detail. Both polymers exhibited similar optical and electrochemical properties with optical band gap of around 1.75 eV as result of LUMO levels near −3.4 eV and high-lying HOMO levels of ∼5.2 eV. Bulk heterojunction photovoltaic devices using these polymers electron donors along with PC70BM as the electron acceptor, gave power conversion efficiency of 1.60% and 0.75% for p(C12-DPP-F) and p(C8-DPP-F) respectively.

Synthesis and photovoltaic properties of furn linked diketopyrrolopyrrole – fluorene based polymers are described. Photovoltaic devices out of these polymers showed power conversion efficiency up to 1.6%. Their OPV performances are significantly improved compared to thiophene linked (diketopyrrolopyrrole-fluorene) polymer.Figure optionsDownload as PowerPoint slide