Distance-resilient conductivity in p-doped polythiophenes

Area of Science:

• Organic electronics
• Materials science
• Polymer chemistry

Background:

• Scalable organic electronic devices require efficient charge transport over long distances.
• Doped conjugated polymers are key materials, but their conductivity often degrades over distance.

Purpose of the Study:

• To assess conductivity and distance-resilience in doped polythiophene films with varying side chains.
• To identify strategies for enhancing long-range charge transport in organic semiconductors.

Main Methods:

• Fabrication and characterization of doped polythiophene films with alkyl and oligoether side chains.
• Measurement of conductivity over five orders of magnitude in distance (nm to mm).
• Kinetic Monte Carlo simulations of nanoscale terahertz conductivity data.

Main Results:

• Polythiophenes with oligoether side chains retained 80-90% conductivity over five orders of magnitude in distance when doped with F4TCNQ.
• P(g42T-T):F4TCNQ exhibited over 100x enhanced long-range conductivity (43 S cm-1) compared to P3HT (0.2 S cm-1).
• Optimized oligoether side chains and doping achieved 330 S cm-1 conductivity; distance-resilience >80% was generalized for conductive regimes (>30 S cm-1).

Conclusions:

• Oligoether side chains enhance dielectric constant and reduce energetic disorder, improving charge transport in doped conjugated polymers.
• This strategy overcomes electrostatic binding and ordering limitations, boosting both short- and long-range conductivity.
• Achieving highly conductive states (>30 S cm-1) is crucial for distance-resilient conductivity in various polymer:dopant systems.