Electrical Transport through Single Nanowires of Dialkyl Perylene Diimide

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• 作者：Beom Joon Kim ; Hojeong Yu ; Joon Hak Oh ; Moon Sung Kang ; Jeong Ho Cho
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：May 23, 2013
• 年：2013
• 卷：117
• 期：20
• 页码：10743-10749
• 全文大小：325K
• 年卷期：v.117,no.20(May 23, 2013)
• ISSN：1932-7455

文摘

We investigated electrical charge transport through individual strands of single-crystalline dipentyl perylene tetracarboxylic diimide (PTCDI-C₅) and dioctyl perylene tetracarboxylic diimide (PTCDI-C₈) nanowires prepared by a solution-phase self-assembly method. Temperature-dependent mobility measurements (100鈥?80 K) revealed distinct electrical transport characteristics in the two types of nanowires. The PTCDI-C₈ nanowire having shorter intermolecular distances exhibited a transition in the electrical transport mechanism from a thermally activated process (the multiple-trap-and-release model) to a band-like transport (the signature of excellent electrical conduction) with increasing temperature. In contrast, the transport through the PTCDI-C₅ nanowire was mostly determined by thermally activated behavior. The observation of band-like transport in the PTCDI-C₈ nanowire was attributed to the small number of charge traps in the constituent molecules. Meanwhile, band-like transport was hardly attainable in the PTCDI-C₅ nanowire due to the presence of a large number of charge traps, which followed an exponential energy distribution. Unlike the case of the single-crystal PTCDI-C₈ nanowire, thin films of polycrystalline PTCDI-C₈ contained significant numbers of exponentially distributed charge traps. Consequently, band-like transport was not observed. Overall, our results presented here demonstrate the importance of attaining good molecular ordering and orientation within the electrically active molecular layer with a high electronic purity for achieving superior electrical transport, i.e., band-like transport.