Photocurrent Enhancement from Diketopyrrolopyrrole Polymer Solar Cells through Alkyl-Chain Branching Point Manipulation

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• 作者：Iain Meager ; Raja Shahid Ashraf ; Sonya Mollinger ; Bob C. Schroeder ; Hugo Bronstein ; Daniel Beatrup ; Michelle S. Vezie ; Thomas Kirchartz ; Alberto Salleo ; Jenny Nelson ; Iain McCulloch
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：August 7, 2013
• 年：2013
• 卷：135
• 期：31
• 页码：11537-11540
• 全文大小：272K
• 年卷期：v.135,no.31(August 7, 2013)
• ISSN：1520-5126

文摘

Systematically moving the alkyl-chain branching position away from the polymer backbone afforded two new thieno[3,2-b]thiophene鈥揹iketopyrrolopyrrole (DPPTT-T) polymers. When used as donor materials in polymer:fullerene solar cells, efficiencies exceeding 7% were achieved without the use of processing additives. The effect of the position of the alkyl-chain branching point on the thin-film morphology was investigated using X-ray scattering techniques and the effects on the photovoltaic and charge-transport properties were also studied. For both solar cell and transistor devices, moving the branching point further from the backbone was beneficial. This is the first time that this effect has been shown to improve solar cell performance. Strong evidence is presented for changes in microstructure across the series, which is most likely the cause for the photocurrent enhancement.