Graphene CVD sheets - updates and market status - Page 8

Wuxi Graphene Film, a wholly-owned subsidiary of The Sixth Elements Materials, has launched a new graphene-enhanced product in the Chinese market: The GF1 Graphene Watch. It is a smart health watch, with CVD graphene film acting as the conductive element for the touch screen (as a replacement for the usually-used ITO).

The Company kindly sent us one of these new watches to try out. So thanks! and here are our impressions: First of all, it is an attractive-looking watch, with a futuristic design and a quality feel to it. The display is a 1.3'' monochrome white OLED with a 128X64 resolution. The watch comes with an accompanying app, and includes features like pulse and heart rate monitoring, step meter, sleep quality tracking and more.

Graphenea reports a successful 2017, with an impressive $1.9 million in sales revenue and a number of milestones. The company reveals that production volumes were expanded for both its staple products graphene oxide and CVD graphene. A 1 tonne per year (tpa) graphene oxide production plant has been established at Graphenea's location in San Sebastian, Spain, where new CVD graphene growth and transfer systems for 100 mm (4) and 150 mm (6) diameter wafers have been installed. Equipment for 200 mm (8) is expected soon.

The increase of production quantity was reportedly accompanied with an enhanced focus on quality and compliance - the graphene oxide product was pre-registered with the European Chemical Agency (REACH pre-registration), a necessary administrative step for producers that sell more than 1 tpa of any chemical. CVD graphene is now produced in a class 1000 clean-room, leading to record-high carrier mobility. Graphenea has also been awarded with an ISO 9001 certificate for Quality Management System.

Norway-based CealTech was established in 2012 to commercialize a patented 3D graphene production method. The company recently received its first prototype proprietary industrial-scale Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) graphene production reactor.

We discussed CealTech's technology and business with the company's marketing and sales manager, Michel Eid. Michael holds a Ph.D. in Solid Mechanics from the Ecole Polytechnique in France, and held various roles in engineeing, manufacturing, sustaining, sales, marketing and business development. Michel joined CealTech in January 2017.

Q: Hello Michael. CealTech is commercializing a patented 3D graphene production method. Can you give us some details on the process and the material you are producing?

Our production process is based on David Boyd’s technique as per Nature communications (DOI: 10.1038/ncomms7620), ‘Single-step deposition of high-mobility graphene at reduced temperatures’. In summary, the substrate is directly exposed to a low-pressure, microwave hydrogen plasma containing small amounts of methane as carbon source. During this process, vertical grown graphene flakes nucleate and arrange perpendicularly to the surface of the substrate forming a so-called 3D network of non-agglomerated graphene flakes.

Norway-based CealTech was established in 2012 to commercialize a patented 3D graphene production method. The company announced today that it has received its first prototype graphene production unit (called FORZA) - an industrial-scale, Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) reactor.

CealTech will start optimizing its first FORZA PE-CVD system in January 2018, where the production parameters will be fine-tuned to ensure consistent and effective production of high quality 3D graphene.

Samsung has announced the development of a unique "graphene ball" that could make lithium-ion batteries last longer and charge faster. In fact, Samsung Advanced Institute of Technology (SAIT) said that using the new graphene ball material to make batteries will increase their capacity by 45% and make their charging speed five times faster. It was also said that batteries that use graphene ball can maintain a temperature of 60 degrees Celsius that is required for use in electric cars.

SAIT's team used a chemical vapor deposition process to grow a graphenesilica assembly, called a graphene ball. Each graphene ball is composed of a SiO_x nanoparticle center and surrounding graphene layers, constituting a 3D popcorn-like structure. The graphene-ball coating improves cycle life and fast charging capability by suppressing detrimental side reactions and providing efficient conductive pathways.

CVD processes are used to create high-quality single layer (also bi-layer and tri-layer) graphene sheets. These kinds of sheets exhibit exceptional properties and can be used in a variety of exciting applications, from touch layers to transistors and sensors. For many years, CVD has been a high cost production process and this graphene is still mostly used in research projects in academic and research institutes, but prices are gradually dropping, to the point where commercial applications are starting to appear on the market.

Recent years have, as we said, brought on a continuing price drop in CVD graphene prices. Spain-based Graphenea, a global CVD graphene leader, has an online shop in which it offers its high-end CVD graphene samples. We have been tracking the prices of Graphenea's CVD graphene since late 2015, and the graph above shows the price decrease.

The National Graphene Institute at the University of Manchester has joined forces with the NPL to develop a guide, as part of NPL's good practice guide series, that conveys "a detailed description of how to determine the key structural properties of graphene, so that the graphene community can adopt a common metrological approach that allows the comparison of commercially available graphene materials. This guide brings together the accepted metrology in this area".

The guide, titled Characterization of the Structure of Graphene, follows last month's release of the NPL's work on the first ISO (International Organization for Standardization) graphene standard. It describes the high-accuracy and precision required for verification of material properties and enables the development of other faster quality control techniques in the future. The guide is intended to form a bedrock for future interlaboratory comparisons and international standards.

Two interesting projects focused on coating single-layer graphene with metal-oxide nanolayers were presented at the latest Thin Films and Coating Technologies for Science and Industry event in the UK. Researchers from Cranfield University, UK, together with collaborators from University of Cambridge and the Centre for Process Innovation (CPI), applied alumina to form a composite barrier layer, while a team from Imperial College London, UK, used the unique properties of strontium titanate to fabricate a tuneable capacitor.

The researchers of the first project explained that in theory, graphene should represent an ideal ultrathin barrier layer, as the pores between carbon atoms are smaller even than the radius of a helium atom. In practice, however, crystal boundaries and missing atoms allow vapor to permeate through the material, and the weak van der Waals bonds between planes mean that even stacks of multiple graphene layers can be penetrated. The solution reported by the team is to take a graphene monolayer formed by CVD, and to then use atomic layer deposition (ALD) to coat it with a 2550 nm thick layer of alumina. Achieving conformal coatings on single-layer graphene is known to be difficult due to the material’s strong hydrophobicity.

OLED displays are very sensitive to oxygen and moisture, and the need to protect the displays is one of the major challenges of this next-generation display technology. First generation OLED displays were protected with a glass barrier, but glass is not easily flexible and so cannot be used in flexible OLEDs. Flexible OLEDs are today encapsulation with a thin-film encapsulation layer made from both organic and in-organic materials, and companies are searching for better OLED encapsulation technologies.

Graphene is the world's most impermeable material, and so the idea of using graphene as a barrier layer for OLED has been around for a while. In 2015 the UK launched a collaboration project called Gravia to develop graphene-based encapsulation, and the project's team has now reported their results.

A team of Researchers from Japan and Taiwan have created a new CVD approach to grow graphene at temperatures as low as 50 °C using a dilute methane vapor source and a molten gallium catalyst. Reducing the temperature in graphene CVD synthesis methods can be extremely beneficial integration of graphene in various applications, like the direct integration of CVD-grown graphene into electronic devices.

The team explains that in silicon-based electronics, the upper temperature threshold that the components can withstand upon graphene integration is around 400 °C. The threshold is even lower for plastic semiconducting devices, which can only withstand up to 100 °C during the graphene growing process. Under traditional conditions, graphene growth occurs at around 1000 °C and has not been suitable for the direct integration into such electronic devices.