Charge Transport in Highly Face-On Poly(3-hexylthiophene) Films

详细信息    查看全文

• 作者：Deepak Gargi ; R. Joseph Kline ; Dean M. DeLongchamp ; Daniel A. Fischer ; Michael F. Toney ; Brendan T. O鈥機onnor
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：August 29, 2013
• 年：2013
• 卷：117
• 期：34
• 页码：17421-17428
• 全文大小：443K
• 年卷期：v.117,no.34(August 29, 2013)
• ISSN：1932-7455

文摘

We report that the 蟺-stacking direction in poly(3-hexylthiophene) (P3HT) films can be made to orient strongly out-of plane by uniaxially straining films in orthogonal directions, providing a valuable opportunity to evaluate charge transport in a very unusual microstructure for this material. The structure of the films was characterized using UV鈥搗isible spectroscopy, X-ray diffraction, and near-edge X-ray absorption fine structure spectroscopy, showing that unstrained films have a weakly edge-on stacking character with a large orientation distribution, whereas films strained biaxially by 100% in orthogonal directions have highly face-on stacking. In the biaxially strained films the face-on packing occurs while the P3HT long axis orientation is found to be only weakly anisotropic in-plane. Charge transport is characterized in an organic thin-film transistor (OTFT) configuration, showing that the saturated field effect mobility in the biaxially strained films is greater than that for unstrained films for channel lengths 鈮?0 渭m. The mobilities are found to have different channel-length dependence, attributed primarily to differences in the field-dependent charge-transport behavior, resulting in the mobility being comparable for channel lengths of 20 渭m. The results suggest that edge-on packing is not a prerequisite for relatively high-field-effect mobility in P3HT-based OTFTs.