Understanding structure-mobility relations for perylene tetracarboxydiimide derivatives

Area of Science:

• Materials Science
• Organic Electronics
• Supramolecular Chemistry

Background:

• Discotic mesophases self-assemble into columnar structures, acting as molecular wires for charge transport.
• Molecular packing critically influences charge carrier mobility in these systems.
• Perylene tetracarboxdiimide derivatives are key organic semiconductors.

Purpose of the Study:

• To elucidate the packing motifs of a perylene tetracarboxdiimide derivative.
• To correlate molecular arrangement with charge carrier mobility.
• To provide insights for rational design of high-mobility organic semiconductors.

Main Methods:

• Combined wide-angle X-ray scattering (WAXS) experiments and molecular dynamics (MD) simulations to determine molecular packing.
• Utilized pulse-radiolysis time-resolved microwave conductivity (TRMC) and non-adiabatic Marcus charge transfer theory simulations to assess charge mobility.
• Performed statistical analysis to evaluate the impact of structural defects.

Main Results:

• Identified specific packing motifs of the perylene tetracarboxdiimide derivative.
• Demonstrated that a helical arrangement with a 45-degree twist angle favors hole transport, contrary to the material's typical n-type behavior.
• Quantified the significant suppression of charge transport by structural defects.

Conclusions:

• The helical molecular packing in discotic mesophases can facilitate hole transport in organic semiconductors.
• Structural integrity is crucial for efficient charge mobility.
• This work offers a pathway for designing improved perylenediimide-based materials for organic electronics.