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Graphene may displace carbon nanotubes and even Indium Tin Oxide (ITO) in some applications. Cathleen Thiele reports.
Carbon Nanotubes (CNTs) have not yet met commercial expectations from a decade ago, and now hot on its heels is graphene. Graphene is considered a hot candidate for applications such as computers, displays, photovoltaics, and flexible electronics.
IDTechEx market forecasts indicate that CNT and graphene transistors may be commercially available in volume from 2015 onwards, according to the new report "Carbon Nanotubes and Graphene for Electronics Applications 2011-2021". According to IDTechEx, the biggest opportunity for both materials is in printed and potentially printed electronics, where the value of these devices that partly incorporate these materials will reach over $44 billion in 2021.
In a comparably short time a large amount of graphene materials have become commercially available contributing to further advancements and application development. At a fraction of the weight and cost of CNTs, graphene may displace carbon nanotubes and even Indium Tin Oxide (ITO) in some applications.
Displays and PV are key drivers
Flexible, see-through displays may be the one application that finally puts graphene into the commercial spotlight. Combined with other flexible, transparent electronic components being developed at Rice University and elsewhere, the breakthrough could lead to computers and solar cells that wrap around just about anything. IDTechEx predicts a market volume of over $25 billion in 2021 for OLED displays and PV alone, some of which will use graphene.
Graphene and its compounds are increasingly used to make transistors that show extremely good performance - a progress that comes with new cheaper production processes for the raw material. Transistors on the basis of graphene are considered to be potential successors for the some silicon components currently in use. Due to the fact that an electron can move faster through graphene than through silicon, the material shows potential to enable tetrahertz computing.
Promise for CNTs
On the other hand, carbon nanotubes are still a strong focus of research. They too are used for making transistors and are applied as conductive layers for the rapidly growing touch screen market. Still considered a viable replacement for ITO transparent conductors in some applications, CNTs are not out of the game yet. While the cost of carbon nanotubes was once prohibitive, it has been coming down in recent years as chemical companies build up manufacturing capacity.
However, there are still hurdles to overcome on both sides. For carbon nanotubes these are especially related to the separation issue and consistent growth. Without the latter, carbon nanotubes will probably never be used for high-volume electronic applications. Graphene, on the other hand, lacks the ability to act as a switch because it has no band gap. However, recent activities of several academic institutions show promise that this restraining issue will soon be solved.
Printed Electronics Market
Nevertheless, a very important result from both sides for the printed electronics market are printable CNT inks and graphene-based inks that are beginning to hit the market.
The upcoming Printed Electronics & Photovoltaics USA conference and exhibition, which will take place in Santa Clara on November 30 and December 1.
Dr Narayan Hosmane from Northern Illinois University will explain how he almost by accident produced high-yields of graphene instead of the expected single-wall carbon nanotubes by using the Dry-Ice Method. Synthetic methodologies for producing graphene on large quantities will be the topic of his presentation.
On the applications side, Kate Duncan from CERDEC, the U.S. Army Communications-Electronics Research, Development and Engineering Center, will go into detail about direct write approaches to nanoscale electronics.
Polymer solar cells have made significant progress in the past few years. Prof Yang Yang, head of the Yang Group at University of California, Los Angeles (UCLA), will give a brief summary on the state-of-the-art status on this and UCLA developments with G-CNTs, a hybrid graphene-carbon nanotube material.
US company Vorbeck Materials Inc. says that products using their patented graphene based electronic ink will appear in major retail stores sometime this year. Dr Sanjay Monie, Technology Development Manager, will give the latest R&D news on the Vor-ink line of conductive inks and coatings for the printed electronics industry, the world's first graphene-based commercial products.
Stephen Turner, Brewer Science, will talk about Aromatic Hydrocarbon Functionalisation of carbon nanotubes for conductive applications, "a new functionalisation path that affords high concentration dispersions without destroying the electronic properties of the nanotube," as he puts it. CNTRENE carbon nanotube solutions is only one of the innovative materials developed at Brewer Science for applications in semiconductors, advanced packaging/3D ICs, MEMS, displays, LEDs, and printed electronics.
And of course, applications of carbon nanotubes will be among the topics: Only recently, SouthWest Natnotechnologies (SWeNT) received a two-year, $500,000 Oklahoma Research Grant to commercialize printed TFTs using semiconducting inks, based on its single-wall carbon nanotube (SWCNT) technology in collaboration with Panasonic Boston Lab (PBL). Dr Philip Wallis, Director of Operations at SWeNT, the leading SWCNT producer in the US, will tell us more about their proprietary V2V ink technology and how they fabricate and test the TFT devices to assure the necessary performance is demonstrated.
And last, but not least, CNT field emission will be the topic of Dr Jamie Nova's talk, Director of Operations at Applied Nanotech (ANI). The company offers a wide range of other metallic inks and pastes. At the 2010 show Applied Nanotech announced the introduction of one of the most suitable potential replacements for coated substrates - EXCLUCENT, substrates on flexible transparent PET utilising copper-based metallic mesh.
Cathleen Thiele is Technology Analyst, IDTechEx For more information, visit www.idtechex.com