Amorphized graphene: A stiff material with low thermal conductivity

TL;DR

This study investigates amorphized graphene, revealing it has high elastic modulus and strength but low thermal conductivity, making it a unique carbon-based material with potential applications requiring stiffness and thermal insulation.

Contribution

The paper provides a comprehensive atomistic analysis of the mechanical and thermal properties of amorphized graphene, highlighting its unusual combination of high strength and low thermal conductivity.

Findings

Amorphized graphene exhibits an elastic modulus of ~500 GPa.

Tensile strength of amorphized graphene is ~50 GPa at room temperature.

Thermal conductivity is approximately 15 W/mK, two orders lower than pristine graphene.

Abstract

All-carbon heterostructures have been produced recently via focused ion beam patterning of single layer graphene. Amorphized graphene is similar to a graphene sheet in which some hexagons are replaced by a combination of pentagonal, heptagonal and octagonal rings. The present investigation provides a general view regarding phonon and load transfer along amorphous graphene. The developed models for the evaluation of mechanical and thermal conductivity properties yield accurate results for pristine graphene and acquired findings for amorphized graphene films are size independent. Our atomistic results show that amorphous graphene sheets could exhibit a remarkably high elastic modulus of ~500 GPa and tensile strengths of ~50 GPa at room temperature. However, our results show that mechanical properties of amorphous graphene decline at higher temperatures. Furthermore, we show that amorphized graphene present a low thermal conductivity ~15 W/mK which is two orders of magnitude smaller than pristine graphene, and we verify that its thermal conductivity is almost insensitive to temperature since it is dominated by phonon-defect scattering rather than phonon-phonon scattering. Finally, our results show that amorphized graphene structures present a remarkably high elastic modulus and mechanical strength, along with a low thermal conductivity, which is an unusual combination for carbon-based materials.