Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes
Molecular length dictates the nature of charge carriers in single-molecule junctions of oxidized oligothiophenes
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DOI：
10.1038/nchem.2160
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发表时间：
2015-03-01
期刊：
影响因子：
21.8
通讯作者：
Campos, Luis M.
中科院分区：
文献类型：
--
作者：
Dell, Emma J.;Capozzi, Brian;Campos, Luis M.
为了开发用于电子器件的先进材料，设计具有可调功能的有机结构单元并在分子水平上研究其性质是至关重要的。对于有机电子和光伏应用，改变电荷载流子的性质并因此产生电子供体或受体的能力是至关重要的。在这里，我们证明了单分子结中的电荷载流子可以在含有缺电子噻吩-1，1-二氧化物（TDO）构建块的分子家族中进行调谐。TDO的低聚物被设计为增加电子亲和力并保持离域前线轨道，同时显著降低传输能隙。通过热电势测量，我们表明，占主导地位的载流子从空穴到电子的TDO单元的数量的增加。这导致了一种独特的系统，其中电荷载流子取决于主链长度，并提供了一种新的手段来调整有机材料中的p型和n型传输。
To develop advanced materials for electronic devices, it is of utmost importance to design organic building blocks with tunable functionality and to study their properties at the molecular level. For organic electronic and photovoltaic applications, the ability to vary the nature of charge carriers and so create either electron donors or acceptors is critical. Here we demonstrate that charge carriers in single-molecule junctions can be tuned within a family of molecules that contain electron-deficient thiophene-1,1-dioxide (TDO) building blocks. Oligomers of TDO were designed to increase electron affinity and maintain delocalized frontier orbitals while significantly decreasing the transport gap. Through thermopower measurements we show that the dominant charge carriers change from holes to electrons as the number of TDO units is increased. This results in a unique system in which the charge carrier depends on the backbone length, and provides a new means to tune p- and n-type transport in organic materials.