Application of Two-Dimensional Conjugated Benzo[1,2-b:4,5-b鈥瞉dithiophene in Quinoxaline-Based Photovoltaic Polymers

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• 作者：Ruomeng Duan ; Long Ye ; Xia Guo ; Ye Huang ; Peng Wang ; Shaoqing Zhang ; Jianping Zhang ; Lijun Huo ; Jianhui Hou
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：April 10, 2012
• 年：2012
• 卷：45
• 期：7
• 页码：3032-3038
• 全文大小：408K
• 年卷期：v.45,no.7(April 10, 2012)
• ISSN：1520-5835

文摘

Two new donor鈥揳cceptor (D鈥揂) alternative copolymers, PBDTDTQx-T and PBDTDTQx-O, were designed and synthesized to investigate the influence of two-dimensional conjugated structure on photovoltaic properties of conjugated polymers. In these two polymers, PBDTDTQx-O was used as control material, which is an alternative copolymer based on a quinoxaline derivative (DTQx) and alkoxy-substituted benzo[1,2-b:4,5-b鈥瞉dithiophene (BDT-O) unit; PBDTDTQx-T has an identical conjugated backbone as PBDTDTQx-O, but a simple two-dimensional conjugated BDT unit (BDT-T) was used to replace the alkoxy-BDT. The polymers were characterized by TGA, UV鈥搗is absorption, electrochemical cyclic voltammetry, hole mobility of space-charge-limited current (SCLC) model, and photovoltaic measurements. It was found that PBDTDTQx-T exhibits similar molecular energy levels and higher hole mobility than PBDTDTQx-O. The power conversion efficiency (PCE) of the polymer solar cells (PSCs) based on PBDTDTQx-T: [6,6]-phenyl-C-71-butyric acid methyl ester (PC₇₁BM) = 1/2 (w/w) reached 5%, which is 60% higher than that of PBDTDTQx-O-based PSC. On the basis of these results, it can be concluded that the application of two-dimensional conjugated structure would be a feasible approach to improve photovoltaic properties of conjugated polymers.