Charge-Transport Solution-State Seeding and Growth of Conjugated Polymers into Well-Defined Nanowire

Controlling the nanoscale morphology of the conjugated polymers (CPs) has been approaching an amount of interest due to its possibility of adjusting charge transfer property. In particular, one-dimensional nanostructures are ideal for charge transfer as they have effective carrier transport properties along the anisotropic stacking directions. Along this line, the pre-assembly of conjugated nanowires (NWs) in the solution state has drawn great interest as a potential replacement for the post-annealing process, securing roll-to-roll manufacturing with a large-area production and a significant cost decrease. The whisker method and the mixed solvent method are frequently utilized as typical solution processing techniques to provide additional driving forces for CPs assembly. Herein, in order to accomplish NW growth and doping without a physical driving force simultaneously, we have focused on charge transfer at the CPs and dopant contact, which can cause seeds-triggering growth of the CPs, rather than the doping procedure, which is often used to tune the electrical property of the CPs to induce the enhancement of the conductivity. Specifically, we will talk about the charge-transport driven CPs-crystal seeding and growth into NWs by adding dopant. Interestingly, it is clearly confirmed through in-situ liquid-cell TEM that controlling the concentration of the dopant or the molecular weight of the CP may have a strong effect on the formation of the NWs in the solution-state. This study might provide an innovative manufacturing strategy for mass production of high-efficiency doped organic semiconductor NWs for optoelectronic devices through solution-processing.