Charge transport in semiconductors with multiscale conformational dynamics

Area of Science:

• Organic electronics
• Materials science
• Condensed matter physics

Background:

• Charge transport in organic semiconductors is complex, influenced by nuclear motion dynamics.
• Traditional models (static disorder, averaged Hamiltonians) fail when nuclear and charge dynamics are coupled.

Purpose of the Study:

• To develop a novel model Hamiltonian for simulating charge transport in organic semiconductors.
• To accurately describe charge transport when carrier and nuclear dynamics are inseparable.

Main Methods:

• Developed a model Hamiltonian incorporating Langevin oscillators to represent nuclear modes.
• Performed molecular dynamics simulations (nanoseconds) on discotic liquid crystal mesophases.
• Evaluated electronic couplings to derive realistic Hamiltonian parameters.

Main Results:

• Identified a limited set of Langevin oscillators sufficient to describe electron-coupled nuclear modes.
• The model Hamiltonian accurately captures charge transport dynamics.
• Successfully simulated systems with both slow (ns) and fast (fs) nuclear motions.

Conclusions:

• The developed model Hamiltonian provides a robust framework for studying charge transport in organic semiconductors.
• This approach bridges the gap between dynamic and static disorder models.
• Applicable to a wide range of organic electronic materials and conditions.