Controlled steric selectivity in molecular doping towards closest-packed supramolecular conductors
Controlled steric selectivity in molecular doping towards closest-packed supramolecular conductors
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DOI：
10.1038/s43246-020-00081-3
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发表时间：
2020-11-04
影响因子：
7.8
通讯作者：
Watanabe, Shun
中科院分区：
文献类型：
--
作者：
Kohno, Shinya;Yamashita, Yu;Watanabe, Shun
分子掺杂技术的最新发展使得聚合物半导体具有极高的载流子密度，由于分子掺杂剂独特的尺寸、构象和空间效应，表现出极大的多样性。然而，空间效应如何限制掺杂效率以及掺杂剂在聚合物中的容纳程度仍存在争议。在这里，我们采用两种具有不同烷基侧链密度的不同共轭聚合物，其中聚合物通过阴离子变化进行掺杂，从而允许具有不同静电势和形状的分子掺杂剂的掺入有更大的变化。考虑到共轭聚合物中独特的空隙空间，我们表征了空间效应的掺杂效率。我们的研究表明，具有稀疏烷基侧链的聚合物的掺杂效率明显高于具有密集侧链的聚合物。最密堆积超分子是通过稀疏聚合物和大掺杂剂的特殊组合实现的，具有高电导率、空气稳定性和非常高的功函数。这项工作为克服分子掺杂中的空间效应提供了重要的见解。
Recent developments in molecular doping technologies allow extremely high carrier densities in polymeric semiconductors, exhibiting great diversity because of the unique size, conformation, and steric effect of molecular dopants. However, it is controversial how steric effects can limit the doping efficiency and to what extent dopants can be accommodated in polymers. Here, we employ two distinct conjugated polymers with different alkyl side-chain densities, where polymers are doped via anion-change, allowing greater variation in the incorporation of molecular dopants having different electrostatic potentials and shapes. We characterize the doping efficiency with regard to steric effects, considering the unique void space in the conjugated polymers. Our study reveals that doping efficiency of polymers with sparse alkyl side-chains is significantly greater than that with dense side-chains. A closest-packed supramolecule is realized with a particular combination of a sparse polymer and a large dopant, giving rise to high conductivity, air stability, and remarkably high work function. This work provides a critical insight into overcoming steric effects in molecular doping.