Improving the Photovoltaic Performance of Polymer Solar Cells Based on Furan-Flanked Diketopyrrolopyrrole Copolymers via Tuning the Alkyl Side Chain

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• 作者：Weilong Zhou ; Chengzhuo Yu ; Huajie Chen ; Tao Jia ; Weifeng Zhang ; Gui Yu ; Fenghong Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 10, 2016
• 年：2016
• 卷：120
• 期：9
• 页码：4824-4832
• 全文大小：647K
• ISSN：1932-7455

文摘

Two furan-flanked diketopyrrolopyrrole copolymers, poly(3,6-difuran-2-yl-2,5-di(alkyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-altthienylenevinylene) with different alkyl side chains (PDVFs), have been synthesized and applied as a donor in polymer solar cells (PSCs). The PSC based on a blend of PDVF-8 with 2-octyldodecyl and [6,6]-phenyl-C71-butyric acid methyl ester (PC₇₁BM) as an active layer has shown a better device performance than the PSC based on a blend of PDVF-10 with 2-decyltetradecyl and PC₇₁BM. Tuning the alkyl side chains attached on the PDVFs leads to an increase of power conversion efficiency from 3.57% (PDVF-10) to 4.56% (PDVF-8) due to enhancements of short circuit current and fill factor. The effect of different alkyl side chains on the phase separation of the PDVF/PC₇₁BM thin film has been investigated by using atomic force microscopy, transmission electron microscopy, and X-ray photoemission spectroscopy depth profiling in details. Furthermore, impedance spectroscopy was used to analyze the relationship between the phase separation of the PDVF/PC₇₁BM blend films and the PSCs performance.