Your Graphene Questions – Answered by General Graphene Corporation
As the world’s leading source for scalable and affordable large-area CVD graphene and 2D carbon materials, our team is equipped to address your graphene questions. Whether you are a researcher exploring the cutting-edge applications of graphene, an industry professional seeking innovative materials for your projects, or a technology enthusiast curious about the limitless possibilities of 2D carbon materials, we are here to provide comprehensive solutions and expert guidance.
What is graphene?
Graphene is an ultrathin allotrope of carbon (diamond and graphite are the other common allotropes of carbon). It consists of a single layer of sp2-bonded carbon atoms with each atom bound to three neighbors in a honeycomb structure.
Single atom thick graphene is sometimes called monolayer graphene or single-layer graphene and abbreviated as 1LG. Bilayer graphene consists of two well-defined stacked graphene layers (2LG). Few layer(s) graphene consists of three to ten well-defined stacked graphene layers (FLG).
Graphene may be synthesized from a gaseous carbon source at high temperatures using a process known as chemical vapor deposition (CVD). Another method uses a chemical process, acids, and heat to exfoliate graphite to produce graphene in a powder form. These graphene powders include graphene oxide (GO), a compound of carbon, oxygen and hydrogen) reduced graphene oxide (rGO), a compound with less oxygen and more carbon than GO; graphene nanoplatelets (GNP) short stacks of platelet-shaped graphene sheets that are identical to those found in the walls of carbon nanotubes, but in a planar form. Other carbon materials closely related to graphene include fullerenes (also known as “Bucky balls”) graphene quantum dots (GQD) and carbon nanotubes.
What is CVD graphene?
To understand what CVD graphene is, it is important to understand the definition of CVD. Chemical Vapor Deposition (CVD) is a process involving the high-temperature activation of gaseous hydrocarbons (e.g., methane) in the presence of a catalytic substrate, typically a copper or nickel foil. The subsequent chemical reactions deposit a thin, stable carbon lattice on the catalyst surface.
What are the key properties of graphene?
Graphene is flexible, electrically and thermally conductive, optically transparent, and impermeable.
Graphene’s unique properties stem from its atomic structure, particularly the sp2 hybridized covalent bonding of its carbon atoms, its free Pi electron availability and nanoscale thickness of 0.345 nm. As a reference, 3 million layers of graphene would be only slightly thicker than 1 mm. Graphene stacked >10 layers is technically classified as graphite. Graphene is the thinnest material known to man – so thin, in fact, that it only has two dimensions in a single-layer format. With a density of 0.77 mg/m2, it also has the highest known surface area any material.
Is CVD graphene of consistent quality?
The properties of exfoliated graphenes such as GO and rGO can vary significantly depending on the quality of the mined graphite raw material and exfoliation process used. In contrast, graphene manufactured using CVD, is largely dependent upon highly controlled and predictable industrial material inputs, including the substrate metal foils and the carbon gas precursor. Graphene recipes are designed by varying the pressures and mixtures of the gases used and because a more controllable process is utilized, the quality is generally more consistent.
While a number of factors influence graphene nucleation and growth, it is well established that CVD graphene will always have edges, nanoscale defects and grain boundaries where carbon to carbon bonding can be disrupted. The basic process for CVD graphene production on Copper and Ni is described in the diagram below.
How good is graphene from General Graphene Corporation, a world-leading large-scale graphene manufacturer, producer and supplier?
General Graphene Corporation, a leading large-scale graphene manufacturer and supplier, has developed a series of proprietary CVD manufacturing technologies to develop CVD graphene materials.
The graphene produced on our GG 3.0 system consistently delivers D/G (defect density) ratios below 0.03 and delivers a monolayer graphene with minimal (1-5%) multilayer coverage.
However, when it comes to graphene, we believe that “good” is a relative measure – what may be “good” for one application may not perform for another. Thus, we eschew labels such as “good” because what ultimately matters most is whether the graphene performs. Graphene is not a “one size fits all material” and must be designed to consistently meet the performance needs of industry and the user.
Among the properties/characteristics with respect to which we can optimize our graphene to meet the needs of the application are:
Crystal sizes: From nm to µm to mm range
Coverage: 95% to 99.99%
Sheet Resistance: < 1000 Ω/sq down to 20 Ω/sq, depending on number of graphene layers and growth conditions.
How many layers of graphene do you make?
We make single layer graphene, and few-layer graphene up to 3 layers (defined as several single layer graphene sheets stacked on top of each other). We can also produce multilayer graphene on nickel foam.
Is graphene expensive?
Purchasing graphene has been difficult and incredibly expensive. However, because cost is arguably the biggest impediment to the commercialization of graphene, General Graphene’s manufacturing and graphene transfer systems were specifically designed to produce industrial scale, low-cost and consistent graphene.
At General Graphene, the graphene cost will generally be a function of volumes and the affordability of graphene in the application for which it is intended.
Can I get large quantities of graphene?
With our proprietary roll-to-roll CVD processes, General Graphene is uniquely positioned in the mass volume manufacturing of graphene.
Our technology enables us to grow graphene in a roll-to-roll format – paving the way for large scale supply and mass adoption.
What are the sheet dimensions of graphene?
The film dimensions of our graphene are generally limited by a 300 mm width and can be scaled to almost any length that meets our customers’ production and handling requirements.
How do you remove graphene from the growth substrate and apply it to another surface?
There are multiple ways to remove and transfer graphene from the growth substrate to its target substrate. The ideal removal method is dependent upon the application for which the graphene is intended. We use the industry-standard wet transfer route as well as a roll-to-roll transfer route for specific large-scale applications.
Is CVD graphene safe to handle?
It is perfectly safe to handle CVD graphene and there are no known health or safety issues associated with film-based graphene. Numerous carbon medical products have been approved by the FDA since the late 1960s, and the biocompatibility of graphene is well documented. In fact, CVD graphene has shown immense promise as a scaffold structure for the growth and differentiation of various stem cells – further validating its safety and biocompatibility.