There are various methods to produce graphene materials, such as mechanical exfoliation of graphite, liquid-phase exfoliation and reduction of graphene oxide (GO), each with its own set of advantages and disadvantages. Chemical vapor deposition (CVD) is a method of producing graphene that has attracted much attention in the last decade and despite several shortcomings, is considered a leading approach to manufacture graphene, especially for applications like high-performance electronics and sensors, as it can yield high quality graphene sheets with a low defect count and good uniformity.
The CVD process
Generally speaking, the CVD method is based on gaseous reactants that are deposited on a substrate. The graphene is grown on a metallic surface like Cu, Pt or Ir, after which it can be separated from the metal and transferred to specifically-required substrates. When the gases contact the substrate inside the heated reaction chamber, a reaction occurs that creates a film of material on the substrate. The process can be simply explained as carbon-bearing gases that react at high temperatures (900–1100 °C) in the presence of a metal catalyst, which serves both as a catalyst for the decomposition of the carbon species and as a surface for the nucleation of the graphene lattice.
As was mentioned before, conditions like temperature, pressure, duration of time and many more can have a significant influence on the process and so must be carefully monitored.
Advantages and disadvantages
CVD can yield high quality graphene, with common characteristics that may include high homogeneity, imperviousness, high purity, fine grains, good control over layer number and more. However, CVD also comes with several disadvantages - namely a relatively high price of the equipment, toxic gaseous by-products and, as stated before, it is a rather sensitive process that is easily influenced by parameter changes. It is important to note that while CVD is a rather expensive method compared to other methods to produce lower-quality graphene, it is still probably the best way (to date) to acquire high quality graphene, since other ways to do that are even more expensive or complicated.
In addition, the separation (or exfoliation) of graphene from the substrate is known as challenging and it is tricky to accomplish without damaging the structure of the graphene or affecting the properties of the material. Another harrowing task is the creation of a uniform layer of graphene on a substrate, something that is continuously proving to not be easy at all.
Some approaches were and are still being developed to overcome this issue, like modifying the concentration of gases and incorporating spin coating methods, but this remains a challenge. However, despite these challenges, it is important to note that CVD is widely considered as an important and promising method to produce graphene, which is already in use, and will probably be even more so in the future, once further advancements are made. It is noteworthy that CVD is already a dominant manufacturing route for many other nanomaterials, and will assumably be in extremely common use once progress is made to resolve the issues that are currently hindering its acceptance.
While using the CVD method to produce graphene is definitely one the leading approaches in the world, it is still hindered by the challenges mentioned above. Thus, it is currently mostly limited to relatively small volumes and mainly restricted to R&D and academic uses.
However, graphene sheets produced via CVD methods are used in several applications like sensors, touch screens and heating elements. It is believed that once better answers are found to the questions of price and handling of CVD graphene, many more applications will start to appear.
Looking to buy CVD graphene sheets?
If you are interested in buying CVD graphene sheets, check out the Graphene Catalog that lists various CVD produced graphene sheets from several producers.
The latest CVD graphene news:
Tata Steel has developed a new product, a few-layer ﬁlm of rGO along with its collaborators at CeNS, Bengaluru. The company is now starting to mass-produce the ﬁlms and offer them to application developers.
Figure 1: (a) Digital image of rGO/Cu foil (5 cm2). Contactact angle (b) and AFM height profile (c) on rGO/Cu
The rGO ﬁlm is produced (using a modified CVD process) on copper. The ﬁlm's average thickness is 5-10 nm and offers a corrosion rate of 0.02 mm/year (Tafel) and a water contact angle of ~ 97°.
These unique properties make the ﬁlm suitable to protect the copper from corrosion, chemical attacks, and thermal oxidations. It also makes copper hydrophobic and can act as an antibacterial surface.
Poland-based Advanced Graphene Products S.A. (AGP), a graphene flakes and sheet developer, announced that it will go public, with a listing on the NewConnect market, on November 29th.
AGP has an annual capacity of 100Kg for graphene flakes and 150 m2 of large-area graphene sheets. The company is currently preparing to launch a pilot sale of a graphene-based filament for 3D printing.
Metalgrass (Graphene-Info) is now offering a new subscription service for enterprises that want access to our complete collection of market reports.
For $3,500 per year, you will get an Enterprise License to all of our market reports. Metalgrass currently offers 12 market reports, plus 4 handbook guides, and all of these are included in the subscription (bought separately, these will cost over $10,000!). You will also have access to all new reports, updates and guides released in the future (during the yearly subscription period).
Our Enterprise License gives access to your entire organization: you can share the report with all the company employees via mail, shared server or any other digital way.
US-based CVD graphene developer General Graphene Corporation (GGC) has launched its new Gen3.0 CVD graphene production line. This 20-meters long roll-to-roll based system can produce single- and multi-layer graphene materials on copper films up to 400 mm wide.
GGC says that with the new line, its manufacturing capacity exceeds 100,000 m2/year. The company is now able to supply affordable and highly consistent CVD graphene in industrial volumes.
Today we published new versions of all our graphene market reports. Graphene-Info provides comprehensive niche graphene market reports, and our reports cover everything you need to know about these niche markets. The reports are now updated to October 2021.
- The advantages using graphene batteries
- The different ways graphene can be used in batteries
- Various types of graphene materials
- What's on the market today
- Detailed specifications of some graphene-enhanced anode material
- Personal contact details into most graphene developers
The report package provides a good introduction to the graphene battery - present and future. It includes a list of all graphene companies involved with batteries and gives detailed specifications of some graphene-enhanced anode materials and contact details into most graphene developers. Read more here!