Interference enhanced thermoelectricity in quinoid type structures.

Area of Science:

• Molecular electronics
• Quantum phenomena in materials
• Thermoelectric energy conversion

Background:

• Quantum interference (QI) in molecular junctions offers potential for significant thermoelectric effects.
• Understanding molecular structures that optimize thermoelectric properties is crucial for device development.

Purpose of the Study:

• To investigate quantum interference effects in quinoid-based molecular junctions.
• To explore the tunability of thermoelectric properties through chemical modifications of molecular structures.

Main Methods:

• Utilizing density functional theory (DFT) to study electrical conductance (G) and thermoelectric response.
• Employing a semi-empirical interacting model Hamiltonian with the GW approximation for the molecular π-system.

Main Results:

• Quinoid molecules display two distinct destructive QI features near frontier orbital energies, appearing as transmission dips.
• These QI features remain separated despite the addition of electron-donating or withdrawing side groups.
• Transmission dip positions and frontier molecular levels are chemically controllable via side groups and conjugation length.

Conclusions:

• Quinoid molecules possess tunable quantum interference, enabling control over thermoelectric properties.
• The ability to chemically tune these molecules results in high thermoelectric power factors and figures of merit (ZT).
• Quinoid-based molecular systems show promise for efficient thermoelectric device applications.