Charge Transport Backup

Illustration of our research into ion-exchange doping of conducting polymers to control carrier density and improve charge transport.

Using ion-exchange doping, we examine how carrier density, counterion identity and polymer microstructure shape charge transport. This reveals how doping changes structural and dynamic disorder, and how these effects can be controlled to improve conductivity [1].

Illustration of our research into how polymer backbone conformation and molecular disorder govern charge transport.

Working closely with organic chemists, we research how polymer backbone conformation, molecular packing and vibrations govern charge transport. Combining transistor, thermoelectric, optical and structural measurements helps us investigate low-disorder materials with higher mobility [2].

Illustration of our research into out-of-plane charge transport in organic semiconductors using conductive atomic force microscopy.

Using conductive atomic force microscopy, we investigate out-of-plane charge transport through individual molecular layers of organic semiconductors. This allows us to separate bulk and contact resistance and understand transport at the scale of single molecules [3].

Graph illustrating our research into how short contacts between neighbouring polymer chains influence charge transport.

We investigate how charges transfer between neighbouring polymer chains, a key limitation once transport along planar backbones becomes efficient. By relating short interchain contacts to mobility and optical properties, we develop molecular design strategies for faster transport [4].

GIWAXS patterns illustrating our research into how molecular design and doping influence the microstructure of conjugated polymers.

Working with synthetic chemistry groups, we investigate how molecular structure and microstructure determine electronic properties and device behaviour. Materials with new functions and improved performance could support sustainable energy conversion, storage and information processing [5].

Schematic illustrating our research into spin transport in doped conjugated polymers using lateral spin pumping and inverse spin Hall detection.

To understand charge, spin and heat transport, we combine measurements of transport coefficients with optical spectroscopy, spin resonance, scanning probe microscopy and in-operando device studies. These methods reveal the physical processes that control materials and devices [6].

  1. Jacobs, I. E. et al. High-efficiency ion-exchange doping of conducting polymers. Adv. Mater. 34, 2102988 (2022).
  2. Venkateshvaran, D. et al. Approaching disorder-free transport in high-mobility conjugated polymers. Nature 515, 384–388 (2014).
  3. Gicevičius, M. et al. Probing out-of-plane charge transport in organic semiconductors using conductive atomic force microscopy. Adv. Mater. 37, 2418694 (2025).
  4. Thomas, T. H. et al. Short contacts between chains enhancing luminescence quantum yields and carrier mobilities in conjugated copolymers. Nat. Commun. 10, 2614 (2019).
  5. Wang, S. et al. Enhancing the thermoelectric properties of conjugated polymers by suppressing dopant-induced disorder. Adv. Mater. 36, 2314062 (2024).
  6. Wang, S.-J. et al. Long spin diffusion lengths in doped conjugated polymers due to enhanced exchange coupling. Nat. Electron. 2, 98–107 (2019).

Over the past two decades, solution-processed organic semiconductors have emerged as promising materials for flexible, large-area electronics. Their mechanical softness and compatibility with low-cost printing could enable applications ranging from flexible displays and electronic textiles to stretchable bioelectronic devices for health monitoring and treatment.

We investigate the fundamental charge transport physics of these materials and work with organic chemists to establish relationships between molecular structure, microstructure and electronic performance. These insights guide the development of improved materials and devices while helping to address the requirements of emerging applications.

 

We investigate solution-processed organic semiconductors that combine useful electronic performance with mechanical flexibility and low-temperature, large-area fabrication, with potential applications in flexible displays, wearable sensors and soft bioelectronic devices [1].

Organic semiconductors are held together by weak van der Waals forces, so charge transport is highly sensitive to molecular geometry, intermolecular packing and soft vibrations. We investigate how this coupling gives rise to dynamic disorder and transient localisation [2].



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References

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  1. Sirringhaus, H. 25th anniversary article: Organic field-effect transistors: the path beyond amorphous silicon. Adv. Mater. 26, 1319–1335 (2014).
  2. Schweicher, G. et al. Chasing the “killer” phonon mode for the rational design of low-disorder, high-mobility molecular semiconductors. Adv. Mater. 31, 1902407 (2019).