Tuning Solution-State Aggregation for Shearing-Induced Alignment and High Mobility Transport in Conjugated Polymers

Area of Science:

• Materials Science
• Polymer Chemistry
• Organic Electronics

Background:

• Developing high-performance polymer electronics requires understanding how conjugated polymers aggregate into ordered thin films.
• Controlling solution-state aggregation under external forces is crucial for efficient charge transport.

Purpose of the Study:

• To tailor polymer aggregation and responsiveness to solution-shearing forces by tuning intermolecular interactions.
• To achieve efficient charge transport in conjugated polymer films.

Main Methods:

• Systematically modulating backbone-solvent and side chain-solvent interactions in a model n-type conjugated polymer.
• Utilizing backbone-selective (1-chloronaphthalene) and side-chain-selective (trimethylbenzene) solvents.
• Analyzing aggregate structures and film ordering under directional shear.

Main Results:

• Backbone-selective solvation led to loosely packed, rod-like aggregates that aligned efficiently, yielding highly ordered films with electron mobilities up to 4.74 cm² V^-1 s^-1.
• Side-chain-selective solvation resulted in disordered, network-like aggregates that resisted alignment, producing less ordered films with mobilities of 2.20 cm² V^-1 s^-1.
• The strategy demonstrated enhanced charge-transport mobility in two other representative polymers.

Conclusions:

• Intermolecular interaction-driven aggregate design critically dictates shearing-induced structural evolution in conjugated polymers.
• This work provides a robust framework for fabricating high-mobility conjugated polymer films.
• Tuning solvent interactions is key to controlling polymer aggregation for advanced electronics.