태양전지 적용을 위한 poly(oligothiophene-alt-benzothiadiazole)s의 합성과 특성 분석

Abstract

Two kinds of 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), has better intermolecular packing than the other poly(3,3',3"-trihexyl-2,2':5',2"-terthiophene-alt-2,1,3-benzothiadiazole) (P2), and thus P1 is more beneficial for achieving high charge carrier mobility. P1-based device shows the power conversion efficiency as high as 2.19% when blended with [6,6]-phenyl--butyric acid methyl ester after thermal treatment at for 30 min.