Graphene Nanoribbon Based Thermoelectrics: Controllable Self- Doping and Long-Range Disorder

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Advanced thermoelectric materials are crucial for energy harvesting and waste heat recovery.
• Two-dimensional (2D) materials offer unique electronic and thermal properties for thermoelectric applications.
• Controlling material structure at the nanoscale is key to optimizing device performance.

Purpose of the Study:

• To investigate the electronic and thermal properties of functionalized graphene nanoribbons (GNRs).
• To explore the impact of single-sheet and helical architectures on GNR thermoelectric performance.
• To demonstrate a novel approach for tuning doping density without explicit dopants.

Main Methods:

• Utilized multiscale simulations to model GNR behavior.
• Analyzed electronic properties, focusing on doping density and power factor.
• Investigated thermal transport, particularly phonon contributions and their dependence on structure.

Main Results:

• Achieved precise tuning of doping density in planar GNRs through functionalization, enhancing the power factor.
• Observed anomalous length-independent phonon thermal transport in helical GNRs.
• Identified self-interaction in helical structures as a source of disorder that suppresses long-wavelength phonons.

Conclusions:

• Functionalized GNRs present a promising route for developing efficient thermoelectric devices.
• Helical GNR architectures offer unique phonon transport characteristics beneficial for thermoelectric applications.
• Tailoring nanoscale architecture and functionalization provides a powerful strategy for optimizing 2D material thermoelectrics.