The development of new techniques that can be used to modify the molecular orientations and structures of organic compounds in organic thin films is in urgent demand to overcome the low levels of charge transport in such films and to ultimately achieve high-efficiency organic opto-electronics. Here, we report structural transformation and electrical characterization of a poly(3-hexylthiophene) (P3HT) semiconductor thin film under femtosecond laser irradiation at a level below the ablation threshold. A combination of grazing incidence X-ray diffraction and near edge X-ray absorption fine structure analyses reveal that the laser procedure effectively switches the P3HT orientation from edge-on to face-on, and the stability of this face-on orientation was also confirmed. Various laser fluence levels ranging up to the ablation threshold were tested, and the P3HT film with a transformed face-on orientation resulting from the optimized fluence level showed a charge current in the vertical direction three times greater than did the pristine film. This enhancement in the charge current was attributed to the vertical π–π stacking of the face-on orientation. These results also confirmed the effectiveness of our novel method for modifying organic thin films, and we expect this method to be attractive for the development of organic electronics and hybrid device applications.

中文翻译：

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激光诱导的共轭聚合物薄膜的取向转变，增强了垂直电荷传输†

迫切需要开发可用于改变有机薄膜中有机化合物的分子取向和结构的新技术，以克服此类薄膜中电荷传输的低水平并最终实现高效的有机光电技术。在这里，我们报告在飞秒激光辐射下低于消融阈值的水平下，聚（3-己基噻吩）（P3HT）半导体薄膜的结构转变和电特性。掠入射X射线衍射和近边缘X射线吸收精细结构分析的结合显示，激光程序有效地将P3HT方向从“边上”转换为“面上”，并且还确认了该“面上”取向的稳定性。 。测试了各种激光能量密度水平，最高达到烧蚀阈值，最佳通量水平产生的具有面对面转换方向的P3HT薄膜，其垂直方向的充电电流是原始薄膜的三倍。充电电流的这种增强归因于正面朝上的垂直π-π堆叠。这些结果也证实了我们用于修饰有机薄膜的新颖方法的有效性，并且我们希望该方法对于有机电子学和混合器件应用的发展具有吸引力。