Synthesis, Characterization and Optoelectronic Properties of Benzodithiophene Based Copolymers for Application in Solar Cells.

This paper reports on the synthesis and characterization of novel donor-acceptor (D-A) conjugated polymers containing triisopropylsilylethyny(TIPS)benzo[1,2-b:4,5-b']dithiophene-diketopyrrolopyrrole (P1 and P2) through Stille co-polymerization method. Thermal stability, optical and electrochemical properties of these polymers were determined. Optical band gaps of the polymers as calculated from their film onset absorption edges were found to be 1.46 and 1.44 eV, respectively. Electrochemical studies revealed HOMO and LUMO energy levels to be -5.22, -5.60 eV, and -3.76, -4.16 eV, respectively. The polymers were thermally stable up to 400-440 °C. Optoelectronic studies indicated that these materials to be promising candidates in solar cell applications.