Bispyrene functionalization drives self-assembly of graphite nanoplates into highly efficient heat spreader foils

TL;DR

This study introduces bispyrene functionalization to promote self-assembly of graphite nanoplates, creating highly efficient heat spreader foils with superior thermal management capabilities and significant weight reduction.

Contribution

It demonstrates a novel non-covalent functionalization method using bispyrene molecules to enhance thermal contact and conductivity in graphene-based nanopapers.

Findings

Enhanced in-plane and cross-plane thermal diffusivity in nanopapers

Nanopapers outperform copper foil in heat dissipation

Over 90% weight reduction compared to traditional materials

Abstract

Thermally conductive nanopapers fabricated from graphene and related materials are currently showing a great potential in thermal management applications. However, thermal contacts between conductive plates represent the bottleneck for thermal conductivity of nanopapers prepared in the absence of a high temperature step for graphitization. In this work, the problem of ineffective thermal contacts is addressed by the use of bifunctional polyaromatic molecules designed to drive self-assembly of graphite nanoplates (GnP) and establish thermal bridges between them. To preserve the high conductivity associated to defect-free sp2 structure, non-covalent functionalization with bispyrene compounds, synthesised on purpose with variable tethering chain length, was exploited. Pyrene terminal groups granted for a strong {\pi}-{\pi} interaction with graphene surface, as demonstrated by UV-Vis, fluorescence and Raman spectroscopies. Bispyrene molecular junctions between GnP were found to control GnP organization and orientation within the nanopaper, delivering significant enhancement in both in-plane and cross-plane thermal diffusivity. Finally, nanopapers were validated as heat spreader devices for electronic components, evidencing comparable or better thermal dissipation performance than conventional Cu foil, while delivering over 90% weight reduction.