Ultralow Thermal Conductivity and Thermal Diffusivity of Graphene/Metal Heterostructures through Scarcity of Low-Energy Modes in Graphene

In many ultralow thermal conductivity materials, interfaces of dissimilar materials are employed to impede heat flow perpendicular to the interfaces. However, when packed within a distance comparable to the phonon wavelengths, these interfaces are coupled and thus ineffective to scatter low-energy phonons, due to either coherent phonon transmission across the closely packed interfaces or weak coupling of the low-energy phonons and the interfaces. Here, we propose to block the propagation of these low-energy phonons by periodically distributed scarcity of available low-energy phonon modes using graphene/metal heterostructures of transferred graphene and ultrathin metal films. We demonstrate the effectiveness of graphene in blocking propagation of low-energy phonons by comparing the effective transmission probabilities of phonons in a wide range of multilayered structures; we find that interfaces in our graphene/metal heterostructures remain decoupled even when the spacing between interfaces is <2 nm. With the proposed strategy, we successfully achieve an ultralow thermal conductivity of Λ = 0.06 W m-1 K-1 and a world-record lowest thermal diffusivity of α = 2.6 × 10-4 cm2 s-1 suitable for thermal insulation. Moreover, we demonstrate the capability to tune the electronic heat transport across the new materials by creating atomic-scale pinholes on graphene through magnetron sputtering, with electrons carrying ≈50% of heat when Λ is ≈0.15 W m-1 K-1. With the ultralow Λ and substantial electronic transport, the new graphene/metal heterostructures could be explored for thermoelectric applications.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:12

Enthalten in:

ACS applied materials & interfaces - 12(2020), 8 vom: 26. Feb., Seite 9572-9579

Sprache:

Englisch

Beteiligte Personen:

Zheng, Weidong [VerfasserIn]
Huang, Bin [VerfasserIn]
Koh, Yee Kan [VerfasserIn]

Links:

Volltext

Themen:

Effective transmission probability
Graphene/metal heterostructures
Journal Article
Thermal insulation
Thermoelectric application
Ultralow thermal conductivity and thermal diffusivity

Anmerkungen:

Date Revised 27.02.2020

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1021/acsami.9b18290

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM305094262