Functionalization mediates heat transport in graphene nanoflakes

Area of Science:

• Materials Science
• Nanotechnology
• Thermal Engineering

Background:

• Graphene's high thermal conductivity is crucial for thermal management but degrades when in contact with substrates.
• Effective heat dissipation in microelectronic devices remains a significant challenge.

Purpose of the Study:

• To enhance the thermal management of micro-heaters by improving heat dissipation pathways in graphene-based films.
• To investigate the role of functionalized graphene oxide interfaces in thermal transport.

Main Methods:

• Experimental fabrication of graphene films bonded to functionalized graphene oxide using amino-silane molecules.
• In situ monitoring using a resistance temperature probe to measure hotspot temperature.
• Pulsed photothermal reflectance measurements to probe thermal resistance and interfacial coupling.
• Atomistic calculations and molecular dynamics simulations to understand interfacial thermal transport mechanisms.

Main Results:

• A substantial reduction in hotspot temperature (∼28 °C) was achieved for a micro-heater operating at 1,300 W cm(-2).
• Functionalization of the graphene-graphene oxide interface improved thermal coupling, reducing thermal resistance.
• Distinct interfacial thermal transport behaviors were observed for different functionalization molecules, linked to molecular chain length and functional groups.
• Molecular dynamics simulations revealed that functionalization constrains phonon scattering, enhancing in-plane heat conduction by preserving phonon lifetimes.

Conclusions:

• Functionalized graphene oxide interfaces offer an effective strategy for improving thermal management in graphene-based micro-heaters.
• The molecular design of interfacial functionalization is critical for optimizing thermal transport.
• This approach enhances heat dissipation by improving in-plane thermal conductivity through controlled phonon behavior.