Mechanisms of Spontaneous Curvature Inversion in Compressed Graphene Ripples for Energy Harvesting Applications via Molecular Dynamics Simulations.

James M Mangum,Millicent N Gikunda,Ferdinand Harerimana,Paul M Thibado

doi:10.3390/membranes11070516

James M Mangum, Millicent N Gikunda + Show 2 more

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https://doi.org/10.3390/membranes11070516

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Journal: Membranes	Publication Date: Jul 9, 2021
Citations: 10	License type: CC BY 4.0

Affiliation: University of Arkansas at Fayetteville

Abstract

Electrically conductive, highly flexible graphene membranes hold great promise for harvesting energy from ambient vibrations. For this study, we built numerous three-dimensional graphene ripples, with each featuring a different amount of compression, and performed molecular dynamics simulations at elevated temperatures. These ripples have a convex cosine shape, then spontaneously invert their curvature to concave. The average time between inversion events increases with compression. We use this to determine how the energy barrier height depends on strain. A typical convex-to-concave curvature inversion process begins when the ripple’s maximum shifts sideways from the normal central position toward the fixed outer edge. The ripple’s maximum does not simply move downward toward its concave position. When the ripple’s maximum moves toward the outer edge, the opposite side of the ripple is pulled inward and downward, and it passes through the fixed outer edge first. The ripple’s maximum then quickly flips to the opposite side via snap-through buckling. This trajectory, along with local bond flexing, significantly lowers the energy barrier for inversion. The large-scale coherent movement of ripple atoms during curvature inversion is unique to two-dimensional materials. We demonstrate how this motion can induce an electrical current in a nearby circuit.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
We studied studied the the dynamics dynamics of of graphene graphene ripples ripples using using molecular molecular dynamics dynamics simulations simulations
The transition rate for barrier barrier crossing was found to be exponential in strain

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Recent developments in low power-consuming circuit designs have reduced input power to nanowatts in active mode and picowatts in standby mode. Some applications operate with an ultra-low duty cycle, which further lowers the overall power requirement [1]. These breakthroughs make it possible to use ambient vibrations as a power source instead of batteries [2,3,4]. There is growing interest in developing power sources that scavenge energy from the local environment [5,6,7,8]

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