Graphene has become one of the most popular materials in science and technology. This is due to its flexibility, the one atom thickness, its matchless strength, and superior conductivity. And although graphene is flexible, taking graphene from a 2D structure to a 3D structure has proven to be challenging. Typically, to get a small wrinkle in a piece of graphene, which essentially transforms it to a 3D structure, it takes some immense manipulation under harsh conditions.
Two specific methods are generally used to get graphene to fold are 1) to manipulate the substrate or to etch catalysts in a pre-patterned fashion, or 2) probes are used to transfer graphene onto substrates comprised of thick polymers.
Unfortunately, what ends up being sacrificed through that manipulation is the graphene’s tunability and precision. The folds end up being random and undefined. The lack of precision puts the desired possible applications of sensors and wearable electronics out of reach since the goal is to increase sensitivity, conductivity, and/or flexibility. If the graphene cannot be precisely handled and shaped, then it can’t more seamlessly cover the devices it is meant to enhance.
Researchers at Johns Hopkins and MIT have found a completely new method for creating 3D structures of graphene. Their findings show that they can fold thin graphene sheets, as thin as 5 nanometers, all while keeping those attributes that everyone loves about graphene—thermal conductivity, thinness, and flexibility. The graphene is manipulated in a way that is self-folding (it can unfold as well), and the shapes that result from the folds are more organized and predictable.
Two key benefits from this method are the compatibility and the scalability. It can be performed with high throughput lithography and implemented on the scale of wafer as well as on a larger scale. Scalability is especially important for the nanomanufacturing industry for large-scale production.
The joint research team’s work also shows how to apply these 3D graphene structures through the encapsulation of live cells and the creation of both nonlinear resistor and creased transistor devices. These applications get closer to their desired use in wearable electronics and in biological and disposable sensors.
How this approach would work for a sensor is that the ultrathin graphene could be manipulated to wrap around a sensor which is usually made on a more rigid 2D substrate. The graphene can do this all the while providing electrical measurements or enhancing optical signals—in 3D. This also increases the surface area for the sensors, making graphene more seamless around the sensor.
For wearable electronics, by creating more precise creases, a band gap is created in the graphene. This can help with making transistors more flexible and compact. Research are looking into future applications which include biosensors that have graphene shells and integrated devices that have creased graphene transistor modules and non-linear resistor modules.
Materials like graphene or CVD graphene can possibly aid in increasing thermal conductivity, flexibility, stability in the fabrication of wearable electronics and biological and/or disposable sensors, as well as in a variety of other applications. To learn about our graphene sheets for sale, contact us today to learn more.