Flexible Electronics, Solar Cells get a Boost

Wednesday, October 14, 2015 @ 05:10 PM gHale

There is now an eco-friendly process that enables spatial control over the electrical properties of graphene oxide. This two-dimensional nanomaterial has the potential to revolutionize flexible electronics, solar cells and biomedical instruments.

By using the probe of an atomic force microscope to trigger a local chemical reaction, Jeffrey Mativetsky, assistant professor of physics at Binghamton University, and PhD student Austin Faucett showed electrically conductive features as small as four nanometers can end up patterned into individual graphene oxide sheets. One nanometer is about one hundred thousand times smaller than the width of a human hair.

Hydrogen Fuel Made Dirt Cheap
Invisibility Cloak Hikes Solar Cell Efficiency
Spray on Solar Cells Closer to Reality
Solar Powered Robots Remain in Action

“Our approach makes it possible to draw nanoscale electrically-conductive features in atomically-thin insulating sheets with the highest spatial control reported so far,” Mativetsky said. “Unlike standard methods for manipulating the properties of graphene oxide, our process can be implemented under ambient conditions and is environmentally-benign, making it a promising step towards the practical integration of graphene oxide into future technologies.”

The 2010 Nobel Prize in Physics ended up awarded for the discovery of graphene, an atomically-thin, two-dimensional carbon lattice with extraordinary electrical, thermal and mechanical properties. Graphene oxide is a closely-related two-dimensional material with certain advantages over graphene, including simple production and processing, and highly tunable properties. For example, by removing some of the oxygen from graphene oxide, the electrically insulating material can end up rendered conductive, opening up prospects for use in flexible electronics, sensors, solar cells and biomedical devices.

The study provides new insight into the spatial resolution limits and mechanisms for a relatively new process for patterning conductive regions in insulating graphene oxide. The minimum conductive feature size of four nanometers is the smallest achieved so far by any method for this material.

Mativetsky said this approach is promising for lab-scale prototyping of nanoscale conductive patterns in graphene oxide.

“There is significant interest in defining regions with different functionalities, and writing circuitry into two-dimensional materials. Our approach provides a way to directly pattern electrically-conductive and insulating regions into graphene oxide with high spatial resolution,” Mativetsky said.

This research not only enables fundamental study of the nanoscale physical properties of graphene oxide but also opens up new avenues for incorporating graphene oxide into future technologies.

Because the process developed by Mativetsky avoids the use of harmful chemicals, high temperatures or inert gas atmospheres, his work represents a promising step toward environmentally-friendly manufacturing with graphene oxide.

“At first, this will mainly be useful for studying fundamental properties and lab-scale devices,” Mativetsky said. “Eventually, this work may help lead to the practical integration of graphene oxide into low-cost and flexible electronics, solar cells, and sensors.”