A nearly 20-year-old scientific prediction has gained experimental support, revealing how graphene’s atomic structure could unlock new possibilities for advanced sensors and electronic devices.
A wrinkle in graphene just a few atoms wide can dramatically alter how electricity behaves in the material. Scientists have now measured this effect in exceptionally sharp folds, providing experimental evidence for a phenomenon predicted nearly 20 years ago.
The discovery, published in Advanced Materials, suggests that researchers could eventually control electrical properties by changing a material’s shape rather than its chemical composition. Graphene, a remarkably strong and conductive material consisting of a single layer of carbon atoms, is already being explored for batteries, computer chips, and other advanced electronics.
How Tiny Wrinkles Change Graphene’s Electrical Properties
The effect is known as flexoelectricity, which occurs when uneven bending causes electrical charges to separate within a material. In graphene, extreme curvature can shift electrons toward one side of its atomically thin structure, creating an electric dipole with oppositely charged regions.
The researchers examined naturally occurring wrinkles whose sharpest bends were compressed into spaces only a few atoms wide, less than a billionth of a meter (about 0.00000004 inches). They found that the sharpness of a wrinkle mattered far more than its overall height. Their estimates indicated that these highly curved regions produced electrical polarization between 100,000 and 10 million times stronger than that associated with much larger, gentler bends.
“The sharpness of the wrinkle turned out to be much more important than its overall size,” said lead author Sathvik Ajay Iyengar, who earned his doctorate at Rice University and is now at the University of California, Berkeley. “That tells us we can potentially tune electrical behavior by carefully controlling curvature at the nanoscale.”
A Scientific Prediction Nearly 20 Years in the Making
The theoretical foundation for the discovery dates back nearly two decades. Vincent Meunier, now head of Engineering Science and Mechanics at Penn State, and Sergei V. Kalinin, now at the University of Tennessee, predicted in a Physical Review B paper that sharply bending graphene could rearrange its electrons and produce an electrical response. At the time, sufficiently clean samples were difficult to fabricate, preventing researchers from directly testing the prediction.
The breakthrough began when Iyengar reexamined experimental data collected with collaborator Manoj Tripathi, now at South Dakota Mines. Their measurements showed unusual electrical signals concentrated around graphene’s sharpest wrinkles. Iyengar brought the findings to Meunier, who had co-advised his doctoral research.
“When Sathvik showed me the measurements he and Manoj had collected, we realized that the unusual signals could provide an experimental connection to an idea we had predicted many years earlier,” Meunier said. “I calculated the effect we had predicted for the specific geometry and compared it to the experiment, and it turns out the fit was almost perfect.”
Measuring Electricity at Atomically Sharp Bends
To investigate the mechanism, the team combined specialized microscopy, laser measurements, and computer modeling. Microscope probes mapped the wrinkles’ shapes, local electrical energy, and current, while Raman spectroscopy revealed where graphene’s atoms were stretched or compressed. Simulations performed using Penn State’s Roar supercomputer helped predict how extreme bending would influence electrons.
Comparing sharply curved wrinkles with nearby flat graphene allowed the researchers to separate the effects of curvature from other influences. The wrinkle tips altered local electrical energy and consistently showed electrical current when approximately one volt was applied. These observations closely matched the team’s calculations and simulations.
The wrinkles effectively acted as microscopic obstacles to electrical transport. Their extreme curvature changed the local electronic environment, providing evidence that flexoelectricity can produce a substantial response even in a material only one atom thick. The measured current required an externally applied voltage, so the results do not demonstrate electricity generation without an external power source.
Toward Electronics Controlled by Shape
The findings point toward a possible method for adjusting the electrical properties of ultrathin materials through precisely controlled bending. Future devices might exploit this behavior to create more sensitive sensors or electronic components whose responses depend on nanoscale geometry.
“Nature already creates these tiny wrinkles for us,” Iyengar said. “Understanding how they influence electrical behavior gives scientists another tool for designing future technologies using the structure of a material itself.”
Reference: “Sub-Nanometer Curvature Unlocks Quantum Orbital Flexoelectricity in Graphene” by Sathvik Ajay Iyengar, James G. McHugh, Jonathan P. Salvage, Robert Vajtai, Venkataramana Gadhamshetty, Alan B. Dalton, Manoj Tripathi, Pulickel M. Ajayan and Vincent Meunier, 25 July 2026, Advanced Materials.
DOI: 10.1002/adma.202518224
The research was supported by the Quad Fellowship, the Sussex Strategy Development Fund, the University of Manchester Dame Kathleen Ollerenshaw Fellowship and the U.S. National Science Foundation under grant numbers OIA-2418752, OIA-1849206 and DGE-2510643. This content is solely the responsibility of the authors and does not necessarily represent the views of the funders.
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