Nonylbisoxazole-based donor-acceptor copolymers for polymer solar cells

A new 4,4 '-dinonyl-2,2 '-bisoxazole (NBO)-based polymer, namely poly{4,8-bis(2-ethylhexoxy)-benzo[1,2-b;3,4-b ']difunan-2,6-diyl-alt-(4, 4 '-dinonyl-2,2 '-bisoxazole)} (PBDFNBO), was synthesized by a Stille coupling polymerization reaction. The copolymer was found to be soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene with excellent film forming properties. The thermal, optical, electrochemical, and photovoltaic properties of PBDFNBO were investigated in detail. Thermo gravimetric analysis (TGA) results indicate that the copolymer possesses good thermal stability. The PBDFNBO film exhibits a narrow absorption band around 300-598 nm (with an optical bandgap of 2.07 eV). The maximum power conversion efficiency (PCE) of the polymer solar cells (PSCs) based on PBDFNBO/PC71BM (1 : 2, w/w) reaches 5.0% with a short circuit current density (J(sc)) of 9.9 mA cm(-2), an open circuit voltage (V-oc) of 0.93 V, and a fill factor (FF) of 0.53 under AM 1.5G, 100 mW cm(-2) illumination.

Automated summary

A new NBO-based polymer PBDFNBO was synthesized with good solubility and film-forming properties, and its thermal, optical, electrochemical, and photovoltaic properties were investigated in detail. The PBDFNBO showed narrow absorption band and high power conversion efficiency in polymer solar cells.