Synthesis and Photovoltaic Properties of Quinoxaline-Based Alternating Copolymers for High-Efficiency Bulk-Heterojunction Polymer Solar Cells

• Published in: Macromolecules 2011-08, Vol.44 (15), p.5994-6001
• Main Authors: Lee, Sang Kyu, Lee, Woo-Hyung, Cho, Jung Min, Park, Song Ju, Park, Jin-Uk, Shin, Won Suk, Lee, Jong-Cheol, Kang, In-Nam, Moon, Sang-Jin
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Exact sciences and technology; Natural energy; Organic polymers; Photovoltaic conversion; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma102943g

A series of quinoxaline-based copolymers, namely, poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(5′,8′-di-2-thienylquinoxaline)] (P1), poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(5′,8′-di-2-thienyl-2,3-bis(4-octyloxyl)phenyl)quinoxaline] (P2), and poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(5′,8′-di-2-thienyl-2,3-bis(4-(3,7-dimethyloctyloxy)phenyl)quinoxaline] (P3), were synthesized and characterized for use in polymer solar cells (PSCs). We describe the effect of modifying the alkyl group of the side chain of the quinoxaline derivatives on the electronic and optoelectronic properties of the polymers. The field-effect hole mobility as well as the electronic energy levels and processability of the materials for PSC applications were investigated. Among the studied quinoxaline-based copolymers, P2 showed the best photovoltaic performance with an open-circuit voltage (V OC) of 0.82 V, a short-circuit current density (J SC) of 9.96 mA/cm2, a fill factor (FF) of 0.49, and a power-conversion efficiency of 4.0% when a P2/PC71BM blend film was used as the active layer under AM 1.5 G irradiation (100 mW/cm2).