1,3,6,8-Tetrakis(methylchalcogeno)pyrenes: Effects of Chalcogen Atoms on the Crystal Structure and Transport Properties
1,3,6,8-Tetrakis(methylchalcogeno)pyrenes: Effects of Chalcogen Atoms on the Crystal Structure and Transport Properties
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DOI：
10.1021/acs.chemmater.2c01544
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发表时间：
2022-07
影响因子：
8.6
通讯作者：
Kirill Bulgarevich;S. Horiuchi;Takuya Ogaki;K. Takimiya
中科院分区：
文献类型：
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作者：
Kirill Bulgarevich;S. Horiuchi;Takuya Ogaki;K. Takimiya
分子半导体结晶成便于分子轨道高效二维(2D)重叠的结构，如人字形、倾斜π堆栈和砖结构(2Dπ堆栈)，有望成为高迁移率有机场效应晶体管(OFET)的活性材料。我们最近报道了1，3，6，8-四(甲硫基)芘(MT-Py)结晶成一种新型的砖结构，表现出高达32cm2V-1s-1的超高迁移率和单晶场效应晶体管(SC-FET)的带状输运。它的氧和硒的类似物，即1，3，6，8-四甲氧基芘(MO-Py)和1，3，6，8-四(甲基硒)Py(MS-Py)，在晶体结构和输运性质方面也同样令人感兴趣。在本工作中，我们合成并表征了MO-Py和MS-Py。它们结晶成砖块结构，乍一看似乎与MT-Py相似，但仔细观察时却明显不同。与MT-P相比，MO-P在两个π堆积方向上的砖结构更加均匀，而MS-P的砖结构高度各向异性且几乎是一维的。通过制备SC-FET，评价了MO-Py和MS-Py的载流子传输特性。SC-FET显示出近乎理想的晶体管特性，具有明显的导通行为和可以忽略的磁滞。而MO-Py和MS-Py表现出较低的空穴迁移率，分别为0.03cm2V-1s-1和7.3cm2 V-1s-1。这些实验迁移率与跳跃模型估算的迁移率是一致的，这与MT-Py的带状输运形成鲜明对比。结果表明，甲基硫基不仅对晶体结构有重要的控制作用，而且对固体中的分子轨道重叠也有很大的影响，从而影响其输运性质。
Molecular semiconductors that crystallize into structures facilitating efficient two-dimensional (2D) overlap of molecular orbitals, such as herringbone, pitched π-stack, and brickwork (2D π-stack) structures, are promising as active materials in high-mobility organic field-effect transistors (OFETs). We have recently reported that 1,3,6,8-tetrakis(methylthio)pyrene (MT-pyrene) that crystallizes into a new type of brickwork structure shows “ultrahigh” mobility of up to 32 cm2V–1s–1and band-like transport in a single-crystal field-effect transistor (SC-FET). Its oxygen and selenium analogues, that is, 1,3,6,8-tetramethoxypyrene (MO-pyrene) and 1,3,6,8-tetrakis(methylseleno)pyrene (MS-pyrene), respectively, are likewise interesting in terms of crystal structure and transport properties. In the present work, MO-pyrene and MS-pyrene were synthesized and characterized. They crystallized into brickwork structures that seemed similar to that of MT-pyrene at first glance but were noticeably different on close inspection. The brickwork structure of MO-pyrene was more even in two π-stacking directions compared with that of MT-pyrene, whereas that of MS-pyrene was highly anisotropic and almost one-dimensional. The carrier transport properties of MO-pyrene and MS-pyrene were evaluated by fabricating SC-FETs. The SC-FETs demonstrated almost ideal transistor characteristics with sharp turn-on behavior and negligible hysteresis. On the other hand, MO-pyrene and MS-pyrene showed relatively low hole mobilities of up to 0.03 and 7.3 cm2V–1s–1, respectively. These experimental mobilities are consistent with those estimated by the hopping model, which is in sharp contrast to the band-like transport of MT-pyrene. The results indicate that methylchalcogeno groups not only contribute to the control of the crystal structure but also have a significant impact on the molecular orbital overlaps in the solid state and, therefore, the transport properties.