In the quest to harness the full potential of graphene for flexible electronics, researchers have encountered a persistent challenge: accurately measuring the electromechanical properties of this atomically thin material when it’s placed on flexible, polymeric substrates. The variability in testing methods has led to inconsistent results, hindering the progress of graphene-based technologies. However, a recent study published in the journal *Materials & Design* (translated as “Materials & Design”) offers a novel solution that could significantly impact the energy sector and beyond.
The research, led by Prashant Narute from the Department of Biomedical Engineering at the University of Massachusetts Amherst, focuses on the often-overlooked aspect of electrical contact (EC) design in electromechanical testing. Narute and his team discovered that when ECs are placed in areas subjected to deformation, the mechanical stiffness mismatches between the ECs, graphene, and substrate create high stress concentrations at the graphene-EC junctions. This leads to premature cracks and increased contact resistance, ultimately resulting in an underestimation of graphene’s intrinsic electromechanical properties.
To address this issue, the researchers proposed an innovative testing method where polymer-supported graphene is affixed to the tester grips using adhesive, and ECs are positioned in regions where deformation is minimal. This approach prevents damage at the graphene-EC junctions during testing, allowing for more accurate measurements.
“The key insight was realizing that the electrical contacts themselves were causing damage to the graphene during testing,” Narute explained. “By repositioning the contacts, we were able to prevent this damage and obtain more reliable measurements of graphene’s electromechanical properties.”
The team validated their method by measuring the electromechanical properties of monolayer and bilayer graphene films. Impressively, they achieved the highest stretchability values of 20% for monolayer graphene and 57% for bilayer graphene—values previously unreported. These findings demonstrate the effectiveness of the proposed method and open up new possibilities for graphene-based flexible electronics.
The implications of this research extend beyond the realm of flexible electronics. In the energy sector, for instance, accurate measurements of graphene’s electromechanical properties are crucial for developing advanced energy storage devices, such as supercapacitors and batteries. Graphene’s exceptional conductivity, strength, and flexibility make it an ideal material for these applications, and the ability to accurately characterize its properties is a significant step forward.
Moreover, the insights gained from this research could influence the design of other two-dimensional materials and their composites, further expanding the potential applications of these materials in various industries.
As Narute and his team continue to refine their method, the future of graphene-based technologies looks increasingly promising. By addressing the challenges associated with measuring graphene’s electromechanical properties, this research paves the way for the development of more reliable and efficient flexible electronics, ultimately benefiting the energy sector and other industries that stand to gain from graphene’s unique properties.
In the words of Narute, “This work is just the beginning. By improving our understanding of graphene’s electromechanical properties, we can unlock its full potential and drive innovation in numerous fields.”