Graphene nanowrinkles could reshape electricity in future ultrathin devices

A recent study conducted by Rice University researchers has revealed that tiny wrinkles in graphene can alter the material's electrical properties, indicating a phenomenon known as flexoelectricity. This is the first time scientists have demonstrated that the shape of a material can influence its electrical behavior at the atomic scale, without the need for additional chemicals or materials. The research, published in Advanced Materials, could pave the way for more sensitive sensors and ultra-thin electronic devices.

Graphene, a single atom thick sheet of carbon, was examined in this study, with researchers focusing on naturally formed wrinkles with extremely small bends, smaller than a billionth of a meter. These bends, when compressed, create an extreme curvature that shifts electrons toward one side of the material, generating two opposite electrical sides.

The researchers used specialized microscope probes and Raman spectroscopy, a technique that reveals how atoms are stretched or compressed, along with computer simulations, to measure the wrinkles' shape, local electrical energy, and electrical current.

The team found that the sharpness of the wrinkles, rather than their height, significantly influenced the electrical response. The electrical charge separation, known as polarization, was found to be between 100,000 and 10 million times stronger than in larger flexoelectric systems. This discovery, dating back to 2008 when theoretical physicist Vincent Meunier predicted that bending graphene could rearrange its electrons and produce an electrical response, has opened up new possibilities for designing materials whose properties can be controlled through structure, rather than chemistry.