A general relationship between disorder, aggregation and charge transport in conjugated polymers

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Physics

Background:

• Conjugated polymers exhibit complex solid-state microstructures due to conformational freedom and weak interchain interactions.
• Understanding charge transport in these amorphous and ordered phases is challenging due to multi-scale electronic processes.
• Fundamental knowledge is crucial for designing advanced organic electronic materials and processes.

Purpose of the Study:

• To propose a unified model for charge carrier transport in conjugated polymer films.
• To elucidate the limiting factors and enabling mechanisms for efficient charge transport.
• To provide insights for molecular design strategies to enhance organic semiconductor performance.

Main Methods:

• Development of a unified theoretical model for charge transport.
• Analysis of charge carrier dynamics in high-molecular-weight semiconducting polymers.
• Correlation of charge transport efficiency with polymer microstructure and disorder.

Main Results:

• Charge transport is primarily limited by trapping due to lattice disorder in high-molecular-weight polymers.
• Short-range intermolecular aggregation is sufficient to facilitate efficient long-range charge transport.
• The model explains the high performance observed in recently reported, poorly ordered polymers.

Conclusions:

• Lattice disorder-induced trapping is the key bottleneck for charge transport in conjugated polymers.
• Efficient charge transport can be achieved even in poorly ordered systems through sufficient intermolecular aggregation.
• The findings suggest new molecular design principles for optimizing next-generation organic electronic materials.