Multiple Resonance Fluorophores as Potential High-Mobility Organic Semiconductors

Area of Science:

• Organic electronics
• Materials science
• Computational chemistry

Background:

• Organic field-effect transistors (OFETs) are key components in logic circuits.
• High charge-carrier mobility in organic semiconductors is crucial for OFET performance.
• Multiple resonance (MR) organic fluorophores are currently researched for narrow-band emission in organic light-emitting diodes (OLEDs).

Purpose of the Study:

• To computationally investigate the potential of multiple resonance (MR) organic fluorophores as high-mobility semiconductors for organic electronics.
• To assess the charge-carrier mobility of MR compounds using theoretical calculations.
• To explore structure-property relationships influencing charge transport in MR fluorophores.

Main Methods:

• Density functional theory (DFT) calculations were employed to determine reorganization energies for charge transfer.
• Analysis of molecular structure effects on reorganization energy.
• Calculation of transfer integrals in MR compound crystals.
• Prediction of electron mobility using the hopping model.

Main Results:

• MR organic fluorophores exhibit small reorganization energies, favorable for efficient charge transport.
• Molecular structure modifications can tune reorganization energies.
• MR compound crystals can possess large transfer integrals, particularly with appropriate substituents.
• Electron mobility exceeding 1 cm² V⁻¹ s⁻¹ was predicted for a specific MR fluorophore, even with the hopping model's underestimation.

Conclusions:

• MR organic fluorophores represent a promising, yet underexplored, class of materials for high-performance organic semiconductors.
• The findings suggest a new avenue for discovering high-mobility materials by repurposing MR fluorophores.
• Further experimental studies on charge transport in MR fluorophores are warranted to validate these computational predictions.