Length-dependent quantum interference and high thermoelectric response ferrocene-modified OPE wires

Area of Science:

• Molecular electronics
• Quantum interference in molecular systems
• Thermoelectric energy conversion

Background:

• Oligo(phenylene-ethynylene) (OPE) molecular wires are key components in molecular electronics.
• Ferrocene integration offers tunable electronic properties.
• Understanding charge transport mechanisms is crucial for device design.

Purpose of the Study:

• Investigate length-dependent charge transport in ferrocene-OPE molecular wires.
• Analyze the role of molecular parity (odd-even effect) on quantum interference.
• Evaluate the thermoelectric potential of these molecular systems.

Main Methods:

• Theoretical analysis of charge transport properties.
• Calculation of quantum interference effects (DQI and CQI).
• Assessment of thermoelectric performance (Seebeck coefficient).

Main Results:

• A coherent, length-dependent transport mechanism governed by quantum interference was revealed.
• Distinct odd-even parity effect observed: odd-ferrocene molecules show destructive quantum interference (DQI), even-ferrocene show constructive quantum interference (CQI).
• Efficient long-range tunneling (decay constant β ≈ 1.1 nm⁻¹) and high thermoelectric potential (Seebeck coefficients > 250 µV K⁻¹) were demonstrated.

Conclusions:

• Quantum interference is a holistic property of the full molecular length, not just the ferrocene core.
• Ferrocene-OPE architecture allows switching between DQI and CQI states via molecular parity.
• This system is a promising platform for tuneable molecular electronic and energy conversion devices.