Carbon Nanotubes: Re-Inventing Organics


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Carbon nanotubes and graphene exhibit extraordinary electrical properties for organic materials, and have a huge potential in electrical and electronic applications such as sensors, microelectronic and semi-conductor devices, field emission displays (FEDs), nanoelectrodes and energy conversion devices (e.g., fuel cells and batteries).

Depending on their chemical structure carbon nanotubes (CNTs) can be used as an alternative to organic and inorganic semiconductors, as well as conductors, but the cost is currently the greatest restraint. However, that has the ability to rapidly fall as applications grow and manufacturing costs improve. Interest is high as CNTs have demonstrated carrier mobilities which are magnitudes higher than silicon, meaning that fast switching transistors can be fabricated. This is in contrast to polymer organic materials that many companies are developing for transistors, where the mobility is currently very low, severely restricting possible uses. Seventy-eight organizations working on the topic are profiled in a new IDTechEx report. For more details, visit www.IDTechEx.com/nano.  

In electronics one of the first applications for CNTs will be transparent conductors. Here, applications are for displays, replacing ITO, touch screens, photovoltaics and display bus bars, connecting TFTs to the front plane, such as OLEDs. IDTechEx's sixth annual Printed Electronics & Photovoltaics USA Conference, December 2-3, 2009 in San Jose, California, covers all the applications, technologies and opportunities in the field of printed electronics and photovoltaics. This event, the world's largest on the topic and growing rapidly every year, will have over 100 world-class speakers--some presenting exclusively for the first time here--covering components, materials and applications. End user speakers include representatives from Procter & Gamble and Kimberly Clark, among others.

For the first time, IDTechEx will have a session dedicated to the rapidly growing topics of CNTs and Graphene for electronics applications, with key companies and research institutes presenting their work:

Founded in 2004, Canatu is a spin-off from the Helsinki University of Technology (TKK) producing films based on carbon nanotubes and their NanoBud™ nanomaterial CNT films. Dr David Brown, CEO, will speak about graphene and carbon nanotubes, especially key innovations and their commercialization as transparent electrodes, semiconductors, resistors, capacitors and saturable absorbers in the display, solar, touchscreen and laser markets. These key innovations are Carbon NanoBuds™, hybrids between traditional CNTs and fullerenes, their CNT and NanoBud™ synthesis processes and the component production method called Direct Dry Printing™, which is able to produce superior quality homogeneous and patterned films, either free-standing or on virtually any substrate at room temperature.

Canatu is focusing on applications of conductive and semiconductive thin films, which range from transparent electrodes in solar cells and displays, saturable absorbers in pulsed lasers to semiconducting films in field effects transistors. Their patterned transparent conductive films are suitable for replacing ITO in LCDs, OLED displays, thin film solar cells, etc. Canatu is working with companies on integrating their films into applications in the areas of e-readers, touch screens, thin film displays and solar cells.

Canatu told IDTechEx, "We will be selling homogeneous and pre patterned films in various conductivities, transparencies, patterning and fractional coverage. We will begin by supplying selected strategic partners with specialty films made to their specifications." Brown tells IDTechEx that they see 300% growth in shipments over the next five years.

Located between San Francisco and San Jose, California in the heart of Silicon Valley, Stanford University is recognized as one of the world's leading research and teaching institutions. One of the widely spread research areas at Stanford are CNT-based Macro and Nanoelectronics with projects on the fundamental understanding of molecule-CNT interaction, the development of metallic/semiconducting CNT separation techniques, the fabrication and optimization of large-area film transistors from purified CNTs, as well as self-assembly and patterning of CNTs.

One group of researchers as Stanford University is working on the utilization of printable carbon nanotubes in high performance energy storage devices. Professor Yi Cui, Assistant Professor of materials science and engineering at Stanford University will talk about their research for new extremely cheap completely printed supercapacitors with ultrahigh specific energy and power, completely printed nanotube current collectors for batteries, and stretchable, flexible and wearable nanotube energy storage devices.

Sohrab Kianian, VP of Business Development at Nantero Inc., a nanotechnology company, will give an insight to their development of carbon nanotube memory and electronics, especially nanotube-based data storage devices. Their high-density nanotube-based non-volatile random access memory (NRAM) device is fabricated incorporating suspended, single or multi-walled CNTs. The company is confident that the logic gates can be integrated with Complementary Metal Oxide Semiconductor (CMOS) technology.

As result of a collaboration with SVTC Technology that was established in 2008 Nantero's proprietary "CMOS-friendly" CNT process will be installed at SVTC's two development fabs, in San Jose, California and Austin, Texas. Apart from their main focus--development of NRAM™ universal memory--Nantero is also working with licensees on other next-generation semiconductor devices incorporating CNT technology, e.g. logic and sensors.

The University of California Los Angeles (UCLA) is a leading academic institute in the state active in various fields related to the topic, as well as printed electronics and photovoltaics. Yang Yang, a professor of materials science and engineering at UCLA, will present their findings with hybrid graphene-carbon nanotube material (G-CNT). The researchers developed a single-step to fabricate G-CNTs in an easy, inexpensive and scalable method. The transparent conductors show great potential to be a high-performance alternative to ITO e.g. in flexible solar cells and other flexible consumer electronics. In comparison to ITO G-CNTs retain efficiency when flexed and are compatible with plastics.

While several organizations have demonstrated CNTs and Graphene for transistors, such as NEC Corporation, HRL Laboratories, IBM, Optomec, Fujitsu and AIST, it will take time before these are commercialized. Conservatively, IDTechEx anticipate this may be available in volume from 2015 onward or, more optimistically, it could be two years earlier.

Graphene and multiwall CNTs (MWCNTs) are already in fairly high production--tens of tonnes per year. Estimates of the amount of MWCNTs produced in 2008 are about 100 tons in total from companies such as Bayer and Showa Denko. In 2009, the amount delivered could double. However, most of these uses are for non electronic/electrical products, or simple applications such as electromagnetic shielding.

Challenges are material purity, device fabrication and the need for other device materials such as suitable dielectrics. However, the opportunity is large, given the high performance, flexibility, transparency and printability.

IDTechEx provides insight in the field of CNT and graphene for printed electronics and photovoltaics in the newly published report Carbon Nanotubes and Graphene for Electronics Applications: Technologies, Players &Opportunities. This concise and unique report gives an in-depth review of the applications, technologies, emerging solutions and players. For more information, visit www.IDTechEx.com/nano.

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