Stretch-induced tunability of electrical transport properties of three-dimensional graphene-based foam structures

TL;DR

This study investigates how pre-stretching influences the electrical resistivity of 3D graphene foams, revealing a transition in temperature dependence and proposing a conduction network model to explain the phenomenon.

Contribution

It introduces a new conduction network model for graphene foams that accounts for multiple conduction mechanisms and explains the effects of pre-stretching on electrical properties.

Findings

Pre-stretching alters the temperature dependence of resistivity.

A conduction network model explains the transition from negative to positive temperature dependence.

Structural modifications can optimize GFs for stretchable electronics.

Abstract

The fast electron transport and superior multidirectional flexibility of three-dimensional graphene-based foams (GFs) are pivotal in the realm of stretchable electronics. We observed pre-stretching induced modulation of the temperature-dependent electrical resistivity of GFs, where, as the pre-stretch strain level increased, the distinct temperature dependence of the resistivity of a GF sample would change and might even exhibit a notable transition from negative dependence to positive dependence. We attempted to interpret the phenomenon by proposing a new conduction network model that represents GF structures as interconnected graphene islands and island/island conduction junctions and incorporates three conduction mechanisms: thermally activated conduction, phonon-limited conduction, and fluctuation-induced tunneling conduction. By fitting-assisted analysis, we found that the temperature dependence of the resistivity of a GF sample primarily relies on the discrete quantities of graphene islands and island/island conduction junctions, and the resistivity originating from each conduction mechanism. As pre-stretch strain level increases, these factors would change due to conduction network alteration, local strain-induced phonon hardening, and local strain-induced transport gap modulation, all resulting from pre-stretching. Our results offer valuable insights into the optimization of GFs-based stretchable electronic devices, such as performance enhancement through structural modifications.