High thermoelectric performance in graphene nanoribbons by graphene/BN interface engineering

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Thermoelectric materials convert heat energy into electrical energy.
• Graphene and hexagonal boron nitride (BN) are 2D materials with unique electronic and thermal properties.
• Heterostructures combining these materials offer potential for advanced thermoelectric devices.

Purpose of the Study:

• To investigate the thermoelectric properties of graphene/BN in-plane heterostructures.
• To understand the influence of structural arrangement on phonon and electron transport.
• To determine the potential for high thermoelectric figure of merit (ZT).

Main Methods:

• Atomistic simulations were employed to model the heterostructures.
• Analysis focused on phonon mode mismatch and electron transmission.
• The Seebeck coefficient and thermoelectric figure of merit (ZT) were calculated.

Main Results:

• Graphene/BN heterostructures exhibit significantly reduced phonon conductance due to phonon mode mismatch.
• Electron transmission is only weakly affected by the heterostructure formation.
• A high thermoelectric figure of merit (ZT > 0.8) was predicted in perfect structures, with ZT = 1.48 achievable with vacancies.

Conclusions:

• Graphene/BN heterostructures are promising for high-performance thermoelectric applications.
• Engineering phonon transport via structural design is key to enhancing ZT.
• Vacancies can further boost thermoelectric performance by degrading phonon transport.