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.

分子掺杂技术的最新发展允许聚合物半导体中极高的载流子密度，由于分子掺杂剂的独特尺寸，构象和空间效应，其表现出极大的多样性。但是，有争议的是，空间效应如何限制掺杂效率，以及掺杂剂可以容纳在聚合物中的程度。在这里，我们采用两种不同的具有不同烷基侧链密度的共轭聚合物，其中聚合物通过阴离子变化进行掺杂，从而允许更大的变化引入具有不同静电势和形状的分子掺杂剂。考虑到共轭聚合物中独特的空隙空间，我们针对空间效应来表征掺杂效率。我们的研究表明，具有稀疏烷基侧链的聚合物的掺杂效率显着高于具有致密侧链的聚合物的掺杂效率。通过稀疏聚合物和大掺杂剂的特定组合实现了最紧密堆积的超分子，从而实现了高电导率，空气稳定性和显着高的功函。这项工作为克服分子掺杂中的空间效应提供了关键的见识。