Crystal structure and modeled charge carrier
Crystal structure and modeled charge carrier
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晶体结构和模拟载流子
DOI：
10.1039/c5nj02302e
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
S. Tokito
中科院分区：
文献类型：
--
作者：
M. Mamada;H. Fujita;K. Kakita;H. Shima;Y. Yoneda;Y. Tanaka;S. Tokito
用单晶X射线分析揭示了具有高电子迁移率的苯并二(噻二唑)(BBT)基有机半导体的晶体结构，并用密度泛函理论和跳跃模型估算了其载流子迁移率。无论相应的对位取代或间位取代衍生物的三氟甲基和三氟甲氧基是什么，晶体堆积和分子间相互作用都是相似的。虽然具有邻三氟甲基的化合物具有扭曲的构象，但邻三氟甲氧基的衍生物具有接近平面的构象。由于邻位三氟甲基通过BBT环之间的短杂原子接触阻止了有效的分子间相互作用，分子具有一维载流子传输路径，导致晶体管器件中的总载流子迁移率较低。另一方面，邻位三氟甲氧基衍生物具有较大的扩散系数，呈人字形堆积。对位和偏位衍生物显示出位于共面和标准π-π堆积方向的分子之间异常大的扩散系数。这种二维结构的形成为使用这些BBT材料的实际有机薄膜晶体管(OTFT)器件提供了高的电子迁移率。
The crystal structures of benzobis(thiadiazole) (BBT)-based organic semiconductors with high electron mobilities were revealed using single-crystal X-ray analyses, followed by density functional theory and hopping modeling to estimate the charge carrier mobility levels. The crystal packings and intermolecular interactions were found to be similar regardless of trifluoromethyl and trifluoromethoxy groups for the corresponding para-substituted or meta-substituted derivatives. Although a compound with ortho-trifluoromethyl groups showed a molecule with a twisted conformation, the ortho-trifluoromethoxy derivative had nearly planar conformation. Since the ortho-trifluoromethyl groups prevent effective intermolecular interactions through short heteroatom contacts between BBT rings, molecules have a one-dimensional charge carrier transport path, resulting in lower overall charge carrier mobility in transistor devices. On the other hand, the ortho-trifluoromethoxy derivative exhibits a herringbone packing with large diffusion coefficients. The para and meta-derivatives showed an unusually large diffusion coefficient between the molecules located in the co-planar and the standard π–π stacking directions. The formation of a two-dimensional structure afforded high electron mobilities in actual organic thin-film transistor (OTFT) devices using these BBT-based materials.