Polymorphism, the ability for a given material to adopt multiple crystalline packing states, is a powerful approach for investigating how changes in molecular packing influence charge transport within organic semiconductors. In this study, a new “thin film” polymorph of the high‐performance, p‐type small molecule N‐octyldiisopropylsilyl acetylene bistetracene (BT) is isolated and characterized. Structural changes in the BT films are monitored using static and in situ grazing‐incidence X‐ray diffraction. The diffraction data, combined with simulation and crystallographic refinement calculations, show the molecular packing of the “thin film” polymorph transforms from a slipped 1D π‐stacking motif to a highly oriented and crystalline film upon solvent vapor annealing with a 2D brick‐layer π‐stacking arrangement, similar to the so‐called “bulk” structure observed in single crystals. Charge transport is characterized as a function of vapor annealing, grain orientation, and temperature. Demonstrating that mobility increases by three orders of magnitude upon solvent vapor annealing and displays a differing temperature‐dependent mobility behavior.

中文翻译：

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Bistetracene薄膜多态控制以阐明分子堆积对电荷传输的影响

多态性是一种给定材料采用多种晶体堆积状态的能力，是研究分子堆积变化如何影响有机半导体内电荷传输的一种有效方法。在这项研究中，分离并表征了一种新型的高性能p型小分子N-辛基二异丙基甲硅烷基乙炔双硬脂醚（BT）的“薄膜”多晶型物。使用静态和原位掠入射X射线衍射监测BT膜的结构变化。衍射数据与模拟和晶体学细化计算相结合，显示了“薄膜”多晶型物的分子堆积，它是从滑移的1Dπ堆积图案转变为经过2D砖层π的溶剂蒸汽退火的高度取向的结晶膜堆放安排 与在单晶中观察到的所谓“本体”结构相似。电荷传输的特征在于蒸汽退火，晶粒取向和温度的函数。证明在溶剂蒸汽退火后，迁移率增加了三个数量级，并显示出不同的温度相关迁移率行为。