In Situ Probing of the Charge Transport Process at the Polymer/Fullerene Heterojunction Interface

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• 作者：Haihua Xu ; Ting Xiao ; Jun Li ; Jiangquan Mai ; Xinhui Lu ; Ni Zhao
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：November 12, 2015
• 年：2015
• 卷：119
• 期：45
• 页码：25598-25605
• 全文大小：453K
• ISSN：1932-7455

文摘

The polymer/fullerene interface (PFI) in polymer solar cells (PSCs) provides an energetic offset for exciton dissociation while at the same time influencing local transport of photocarriers adjacent to the interface. In this paper, we introduce a heterojunction field-effect transistor (FET) structure in charge modulation spectroscopy (CMS) to enable in situ probing of the charge transport process at PFIs. The PFIs formed by fullerene/crystalline polymer and fullerene/amorphous polymer systems are studied and compared, respectively. By correlating the steady-state and frequency-dependent CMS responses of pure polymer, polymer/fullerene bilayer, and polymer/fullerene blend FETs, we demonstrate that through different charge localization effects the interface fullerene molecules can influence the hole transport in both crystalline and amorphous polymer phases. We propose a trade-off between charge transfer and charge transport at PFIs with an aim to enhance the engineering of molecular orientation and packing at the donor鈥揳cceptor interface for high-performance PSCs.