| 초록 |
Two different low-bandgap alternating copolymers composed of thiophene and benzothiadiazole were synthesized via the Stille coupling reaction. The effect of number of alkyl groups attached to oligothiophenes in the repeating unit of the copolymers on their optical, electrochemical, and photovoltaic properties was systematically investigated. One of the new polymers, poly(3,3"-dihexyl-2,2′:5′,2″-terthiophene-alt-2,1,3-benzothiadiazole) (P1), was found to have better intermolecular packing than poly(3,3′3"-trihexyl-2,2′:5′,2″-terthiophene-alt-2,1,3-benzothiadiazole) (P2), which is beneficial for achieving high charge carrier mobility. P1-based device showed the best power conversion efficiency of 2.19% when blended with [6,6]-phenyl-C71-butyric acid methyl ester under the standard solar radiation condition (AM 1.5G, 100mW/cm2). |
