Department of Chemistry, Columbia University, New York 10027, USA.
Department of Applied Physics and Mathematics, Columbia University, New York 10027, USA.
Nat Chem. 2015 Mar;7(3):209-14. doi: 10.1038/nchem.2160. Epub 2015 Feb 2.
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.
为了开发电子设备的先进材料，设计具有可调功能的有机建筑块并在分子水平上研究其性质至关重要。对于有机电子和光伏应用，改变电荷载流子的性质从而创建电子供体或受体的能力是关键。在这里，我们证明在包含缺电子噻吩-1,1-二氧化物（TDO）构建块的分子家族中，可以调节单分子结中的电荷载流子。设计了 TDO 的齐聚物以增加电子亲和力并保持离域的前沿轨道，同时显著减小传输间隙。通过热功率测量，我们表明随着 TDO 单元数量的增加，主要电荷载流子从空穴变为电子。这导致了一个独特的系统，其中电荷载流子取决于主链长度，并为在有机材料中调节 p 型和 n 型传输提供了一种新方法。
