National Nanomanufacturing Network

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InterNano is an open-source online information clearinghouse for the nanomanufacturing research and development (R&D) community in the United States. It is designed provide this community with an array of tools and collections relevant to its work and to the development of viable nanomanufacturing applications.
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Nanomanufacturing: Building a Community of Practice

March 27, 2015 - 4:58am
Establishment of a sustainable nanomanufacturing ecosystem faces numerous challenges due to the inherent nature of nanotechnology, which intersects multiple industries, involves multidisciplinary scientific researchers, while encompassing an extensive range of highly unique technologies including materials, processes, and equipment. As such, building a community of practice entails a broad range of activities from standards, education and workforce development, technology roadmaps, best practices, informatics, environmental health and safety, to commercialization. To ensure progress on all of these fronts, community involvement is essential for providing broad perspectives from a range of stakeholders in industry, government, and academia in order to better understand where fundamental and applied research intersects emerging and established regulatory and commercialization activities and roadmaps. While these issues may be relatively clear cut for specific segments of nanotechnology commercialization, it is not always clear where best practices translate to adjacent application and industry roadmaps. An important activity for building the nanomanufacturing community of practice is thematic workshops involving a group of experts and practitioners in the field. To this end, the NNN has sponsored several thematic workshops since inception including collaborative workshops with NSF (2008 Research Challenges for Integrated SystemsNanomanufacturing (, NNIN (2010 Synergies in Nanoscale Manufacturingand Research (, NIST (2012 Nanofabrication Technologies forRoll-to-Roll Processes (, and a series of workshops on Nanoinformatics (2007-present). The essence of these workshops is to incorporate different viewpoints on topics relevant to the workshop theme in order to better understand methods, challenges, emerging R D, and gaps in research activities towards addressing the associated challenges. The NNN has strived to enhance these workshops by convening a balance of industry, academic, and government participants which, when combined with topical questionnaires distributed prior to the workshop assist in focusing the content of the presentations, discussions, and breakout sessions thereby enabling a productive event with measurable outcomes. Typical work products for these workshops include reports, roadmaps, publications, collaborations amongst participants, proposals, and broader initiatives or funding opportunities. With the goal of contributing towards the establishment of a nanomanufacturing roadmap, as well as formulating a NNN 2.0 initiative, the NNN solicits comments, suggestions and ideas for future topical workshops in nanomanufacturing from our members and stakeholders. Along with suggestions for topics and subtopics, further details including suggested experts and participants, relevant gaps and questions to be addressed in the workshop with respect to the nanomanufacturing enterprise. These activities are an essential component of the NNN and it is critical to our mission that we consider these activities with input from the community as a whole, as well as reach out to the relevant stakeholders, industry and government agencies having significant stake in the topic of interest to obtain their contributions or involvement. We look forward to receiving ideas and suggestions for potential workshops, and will provide feedback in the future in order to prioritize the topics.

EPA proposes reporting and record keeping requirements on nanomaterials

March 27, 2015 - 3:58am
For the first time the agency will use TSCA authority to collect health and safety information on nanoscale chemicals already in use The U.S. Environmental Protection Agency (EPA) is proposing one-time reporting and recordkeeping requirements on nanoscale chemical substances in the marketplace. Nanotechnology holds great promise for improving products, from TVs and vehicles to batteries and solar panels,” said Jim Jones, EPA’s Assistant Administrator for Chemical Safety and Pollution Prevention. “We want to continue to facilitate the trend toward this important technology. Today’s action will ensure that EPA also has information on nano-sized versions of chemicals that are already in the marketplace.” EPA currently reviews new chemical substances manufactured or processed as nanomaterials prior to introduction into the marketplace to ensure that they are safe. For the first time, the agency is proposing to use TSCA to collect existing exposure and health and safety information on chemicals currently in the marketplace when manufactured or processed as nanoscale materials. The proposal will require one-time reporting from companies that manufacture or process chemical substances as nanoscale materials. The companies will notify EPA of: certain information, including specific chemical identity; production volume; methods of manufacture; processing, use, exposure, and release information; and, available health and safety data. Nanoscale materials have special properties related to their small size such as greater strength and lighter weight, however, they may take on different properties than their conventionally-sized counterpart. The proposal is not intended to conclude that nanoscale materials will cause harm to human health or the environment; Rather, EPA would use the information gathered to determine if any further action under the Toxic Substances Control Act (TSCA), including additional information collection, is needed. The proposed reporting requirements are being issued under the authority of section 8(a) under TSCA. The agency is requesting public comment on the proposed reporting and recordkeeping requirements 90 days from publication in the Federal Register. EPA also anticipates holding a public meeting during the comment period. The time and place of the meeting will be announced on EPA’s web page at: ( Additional information and a fact sheet on the specifics of the proposed rule and what constitutes a nanoscale chemical material can be found at: ( Source: EPA (!opendocument)

National Nanotechnology Initiative publishes report assessing the status of EHS risk science

March 27, 2015 - 3:38am
The National Nanotechnology Initiative (NNI) today published the report from the workshop, “Stakeholder Perspectives on Perception, Assessment,and Management of the Potential Risks of Nanotechnology” (R3 Workshop), which was held September 10-11, 2013, in Washington, D.C. The goal of the workshop was to assess the status of nanotechnology environmental, health, and safety (EHS) risk science three years after the development of the 2011 NNI EHS Research Strategy and to identify the tools and best practices used by risk assessors to address the implications of nanotechnology. A wide range of stakeholders including Federal and State regulators, small and large businesses, insurance companies, academic researchers, occupational safety specialists, and public and environmental advocacy groups shared their perspectives on the risk management process; discussed strategies and approaches for improving risk science methods; and examined ways that NNI agencies can assist stakeholders in the image002.jpgresponsible development of nanotechnology. Stakeholders participating in the workshop presented their perspectives and methods used to assess and manage the potential risks of nanotechnology. Research presented at the workshop shows that technical risk data alone will not enable decisions; risk evaluations by different stakeholders with varying biases, values, and stances can affect the perceptions and behaviors (e.g., investment or personal safety decisions) of consumers, regulators, developers, manufacturers, and insurers. Following a robust dialogue among participants, including a variety of stakeholder perspectives, participants identified needs in four areas. (The following list is not prioritized): Communication Resources, including improved transparency in reporting the presence of engineered nanomaterials (ENMs) and continued collaboration among diverse stakeholder groups.Decision Tools, such as improved detection and characterization tools; improved methods for assessing both actual exposure to and potential risk from ENMs; tools to address nanotechnology-related environmental, health, and safety (“nanoEHS”) issues sooner in the product life cycle.Data Resources, such as repositories or databases to facilitate access to or organization of existing information on nanoEHS; methods for accessing and investigating potentially protected information; and continued toxicology studies on the effects of ENMs.Standards and Guidance Resources, in order to facilitate navigation of nanotechnology-enabled applications through the regulatory process and improved data quality and methods for reporting data used in nanomaterial risk assessment. You can download full document from the InterNano Library ( Source: National Nanotechnology Initiative (

Solar Cells with Tunable Colors

March 26, 2015 - 5:27am
With rising levels of atmospheric carbon dioxide and indicators for global climate change increasingly apparent, the search has intensified for more sustainable and renewable alternative energy sources. Photovoltaic (PV) energy has been of interest for the last 40 years; however, the cost of Si-based solar panels is still not cost-effective for widespread usage. In addition to the overall cost, consumer adoption of this technology has been slow due to the unattractive aesthetics of traditional solar panels. Building integrated photovoltaics (BIPVs) such as Dow PowerhouseTM Solar Shingles have reached the market, but have not yet been widely adopted. In order for PV technology to be widely accepted, it will need to be seamlessly incorporated into existing infrastructures such as building and automotive materials, and be available in a variety of colors. Among the various types of emerging PV technologies such as dye-sensitized solar cells (DSSCs), organic cells, and quantum dots (QDs), perovskite solar cells represent one of the most promising sectors. In a span of only 5 years, the efficiency of perovskite PVs has increased from ca. 3% to a current level in excess of 20%. This efficiency is now comparable to that of crystalline Si and semiconductor thin films (e.g., copper indium gallium selenide (CIGS), CdTe) that have been in development since the 1970’s. Perovskite solar technology utilizes a hybrid inorganic-organic halide perovskite (e.g., CH3NH3MI3 where M = Sn, Pb) in combination with n- and p-type charge collection layers. In a promising step toward aesthetically attractive solar panels, Zhang and coworkers describe the fabrication of perovskite photovoltaic devices that are color-tunable. In order to maximize the refractive index contrast among the layers in the device, nanoparticulate films of porous SiO2 (50% porosity) and dense TiO2 (4% porosity) were deposited by simple spin-coating. The combination of the photonic properties of the oxide nanoparticle films and absorptive properties of the overlying perovskite material was used to fine-tune the observed color range from orange to blue. Interestingly, the strategy employed by these researchers may be considered as a biomimetic approach, since beetles and butterflies also employ reflective and absorptive layers that yield a characteristic and often tunable color. Many gemstones such as opals also utilize the photonic crystal effect to give rise to iridescent colors. The use of a photonic phenomenon for color generation in this multilayered PV device is preferred rather than using dyes or pigments, since the latter would likely fade over time. The best power conversion efficiency observed in this work was 8.8% for blue-colored cells. While this is low relative to traditional perovskite-based PV devices, this may be compared to 9.5% for a reference cell employing mesoporous SiO2. Hence, the operating efficiency of the device is not significantly deteriorated by the reflective processes occurring in the photonic component of the device, which is responsible for the observable colors. Further fine-tuning of the perovskite layers, interfaces, and nanoparticle sizes and porosities will likely improve the overall efficiency, while expanding its color palette. It would be interesting to extend this approach to other emerging technologies and thin film semiconductors to introduce other options for colorful solar panels. As decorative options become more plentiful and efficiencies continue to rise, consumers will more likely adopt this technology to power their homes and begin to wean themselves from nonrenewable fossil fuels. Electric and hybrid vehicles employing solar panels that match the color of the exterior paint would also be much more attactive to consumers relative to traditional solar panels already used by some vehicles (e.g., Fisker Karma). Reference: Zhang W, Anaya M, Lozano G, Calvo ME, Johnston MB, Míguez H, Snaith HJ. Highly Efficient Perovskite Solar Cells with Tunable Structural Color. Nano Letters. 2015; 15 (3): 1698-1702 doi: 10.1021/nl504349z ( Image reprinted with permission from American Chemical Society.

Handwritten Patterning of Single-Walled Carbon Nanotubes

March 19, 2015 - 4:29am
Although there are many potential applications for carbon nanotubes (CNTs), their wide scale consumer applications to date have been limited to serving as polymer additives to yield higher-strength composites. Even though bulk nanotubes exhibit tensile strengths much less than individual nanotubes (especially single-walled varieties), bulk CNT additives have been shown to enhance the strength:weight ratio of a variety of sporting equipment such as bicycles, skies, baseball bats, hunting arrows, and surfboards. Beyond their high-strength properties, the extraordinary electrical conductivity of CNTs makes these nanostructures ideal for microelectronics circuitry applications. Using advanced techniques such as near-field electrospinning (NFES), it is now possible to generate conductive nanotube fibers that span up to a few hundred meters. However, current fiber processing techniques are difficult to scale up, and often experience difficulties with nanotube alignment during fiber spinning. This latter limitation is an important consideration for microelectronics applications, since unaligned nanotubes would deleteriously affect the conductivity of the deposited fibers. The recent report by Huang et al. describes an improved fiber-drawing technique that consists of simple handwriting of conductive fibers using a common pen tip. Patterns may easily be placed onto both planar and non-planar substrates using this strategy. The fiber drawing speed is reported to be ca. 10 cm/s, which represents a large improvement relative to other techniques that are much too slow for commercial scale up, with patterning speeds of < 1 mm/s (most often in the mm/s range). Patterning consists of using poly(ethylene oxide), PEO, in the presence of surfactants and carbon nanotubes, which forms a polymeric ‘ink’. The choice of PEO was due to its desirable viscoelastic properties, which allowed for the continuous pulling of fibers from the solution without breakage. In contrast, fibers drawn from solutions of poly(methyl methacrylate), PMMA, commonly used in other patterning techniques, have much larger diameters and inconsistent conductivities due to less effective alignment of nanotubes comprising the fiber. Whereas PEO in the absence of CNTs dried to form nanofibers with diameters of ca. 60 nm, the diameter range of PEO-CNT composite fibers was ca. 300 nm – 3 mm. One is able to vary the diameter of the composite PEO-CNT fibers, based on the solution concentration and volume used in the pen tip. Fiber lengths in excess of 50 cm were achieved using this technique, and featured a high degree of nanotube alignment – especially for low-diameter fibers. Consequently, the conductivity of the fibers were significantly higher than isotropic CNT thin films. In contrast to other techniques that require the use of micro/nanomanipulators to appropriately position fibers into electronic circuitry, this direct-writing procedure is able to place the conductive fibers directly into desired positions with submicron control. The fibers may also be transferred to other substrates after drying without changing their morphologies or electrical conductivities. With a surge in flexible and wearable electronic devices on the horizon, it is essential that techniques exist for the fabrication of flexible conductive wires. This work represents an attractive strategy, and results in fibers that may be easily fabricated using a common pen tip and placed onto a variety of surfaces. Furthermore, the conductivity of the fibers is not altered by repeated bending tests, which should enable this technique to be used for the next generation of flexible touchscreens, wearable electronics, and the batteries or supercapacitors that will be needed to power these devices. Further testing is needed to assess the adsorption of the PEO-CNT fibers to textiles, LCDs, and other surfaces. However, this technique shows promise for the fast assembly and precise placement of conductive fibers into electronic circuits. Reference: Huang S, Zhao C, Pan W, Wu H. Direct Writing of Half-Meter Long CNT Based Fiber for Flexible Electronics. Nano Letters. 2015; 15 (3): 1609-1614 doi: 10.1021/nl504150a ( Image reprinted with permission from American Chemical Society.

NNI Publishes Report on Carbon Nanotube (CNT) Commercialization

March 13, 2015 - 4:35am
The National Nanotechnology Initiative today published the proceedings of a technical interchange meeting on “Realizing the Promise of Carbon Nanotubes: Challenges, Opportunities, and the Pathway to Commercialization" ( held at the National Aeronautics and Space Administration (NASA) Headquarters on September 15, 2014. This meeting brought together some of the Nation’s leading experts in carbon nanotube materials to identify, discuss, and report on technical barriers to the production of carbon nanotube (CNT)-based bulk and composite materials with properties that more closely match those of individual CNTs and to explore ways to overcome these barriers. A number of common themes and potential future research and development priorities emerged: Increased efforts devoted to manufacturing, quality control, and scale-up.Improvements in the mechanical and electrical properties of CNT-based bulk materials to approach the properties of individual CNTs.More effective use of simulation and modeling to provide insight into the fundamentals of the CNT growth process.Improved understanding of the properties of bulk CNT-containing materials at longer length scales.Standard materials and protocols to guide the testing of CNT-based products for commercial applications.Life cycle assessments for gauging commercial readiness.Use of public-private partnerships or other collaboration vehicles to leverage resources and expertise to solve these technical challenges and accelerate commercialization. The outcomes of this meeting, as detailed in this report, will help inform the future directions of theNNI Nanotechnology Signature Initiative “Sustainable Nanomanufacturing: Creating the Industries of the Future,” ( which was launched in 2010 to accelerate the development of industrial-scale methods for manufacturing functional nanoscale systems. You can download full document from the InterNano Library ( .

U.S. National Nanotechnology Initiative 2016 funding brings total to $22 billion

March 12, 2015 - 5:53am
The President’s Budget for Fiscal Year 2016 provides $1.5 billion for the National Nanotechnology Initiative (NNI), a continued Federal investment in support of the President’s priorities and innovation strategy. Cumulatively totaling more than $22 billion since the inception of the NNI in 2001, this funding reflects nanotechnology’s potential to significantly improve our fundamental understanding and control of matter at the nanoscale and to translate that knowledge into solutions for critical national needs. Nearly half of the requested budget is dedicated to applications-focused R D and support for the Nanotechnology Signature Initiatives (NSIs), reflecting an increased emphasis within the NNI on accelerating the transition of nanotechnology-based discoveries from lab to market. The NSIs are multiagency initiatives designed to accelerate innovation in areas of national priority through enhanced interagency coordination and collaboration. Furthermore, the NNI has continued to grow its hallmark environmental, health, and safety (EHS) activities, which now account for more than 10% of the NNI’s total budget (7% in dedicated EHS investments, as shown in the figure at left, plus approximately 3% in additional EHS-related investments within the NSIs). “Right now, the NNI is focused on innovations that support national priorities, while maintaining a strong foundation of fundamental research in nanoscience,” says Dr. Michael Meador, Director of the National Nanotechnology Coordination Office. “Our goal is to create an environment to foster technology transfer and new applications today, while supporting the basic research that will provide a continuing pipeline of new discoveries to enable future revolutionary applications tomorrow.” The President’s 2016 Budget supports nanoscale science, engineering, and technology R D at 11 agencies; another 9 agencies have nanotechnology-related mission interests or regulatory responsibilities. The NNI Supplement to the President’s 2016 Budget documents activities of these agencies in addressing the goals and objectives of the NNI. You can download full document from the InterNano Library ( (

Lower Cost, Roll-to-Roll Production of Carbon Nanotube Based Supercapacitors

March 5, 2015 - 8:03am
Ultra- or supercapacitors are emerging as a key enabling storage technology for use in fuel-efficient transport as well as in renewable energy systems (for instance as power grid buffer). These devices combine the advantages of conventional capacitors – they can rapidly deliver high current densities on demand – and batteries – they can store a large amount of electrical energy. Supercapacitors offer an alternative source of energy to replace rechargeable batteries for various applications, such as power tools, mobile electronics, and electric vehicles. Although the energy density of capacitors is quite low compared to batteries, their power density is much higher, allowing them to provide bursts of electric energy that for instance can help electric cars to accelerate at comparable or better rates than traditional petrol-only engine vehicles, while achieving a significantly reduced fuel consumption (read more about supercapacitors and other nanotechnologies to mitigate global warming ( ). "Among the various types of supercapacitors, carbon nanotube (CNT) based devices have shown an order of magnitude higher performance in terms of energy and power densities," Ramakrishna Podila ( , an Assistant Professor in the Department of Physics and Astronomy at Clemson University, tells Nanowerk. "The bottleneck for transferring this technology to the marketplace, however, is the lack of efficient and scalable nanomanufacturing methods." Reporting their findings in Applied Physics Letters ("Roll-to-roll production of spray coated N-doped carbon nanotube electrodes for supercapacitors ( "), Podila's team at Clemson University, in collaboration with Professor Apparao Rao's lab ( , has now developed a new scalable method to to directly spraycoat CNT-based supercapacitor electrodes. "Much like painting a car or a wall in your home, we can spray CNT solutions on flexible electrodes, porous aluminum foils in our case, to achieve high energy density supercapacitor electrodes without the need of any binder," explains Podila. The resulting supercapacitors have a 10 times higher energy density compared to the state-of-the-art supercapacitors on the market. Theoretically, CNTs offer an ultra-high surface area; in practice, though, the net capacitance of the CNT electrodes is smaller than the predicted values – based on surface area – due to the presence of a so-called small quantum capacitance in series. In this work, the Clemson researchers together with Cornell Dubilier, Inc (a leading capacitor manufacturer in Liberty, SC) and Sai Global Technolgies (a newly founded manufacturer of tailored nanomaterials in San Antonio, TX), have demonstrated that nitrogen doped CNTs electrodes overcome the quantum capacitance limitations and exhibit high power density along with high energy density on par with thin film Li-ion batteries. "The quantum capacitance must be increased, ideally to infinity, for realizing the true potential of nanocarbons in energy storage," remarks Rao, who is director of the Clemson Nanomaterials Center. "Heteroatomic doping, which has been a valuable tool in the semiconductor industry, can provide a solution," adds Podila. "Here we showed that doping provides a handle to control the energy states where electrons could reside in supercapacitor electrode materials and thereby increase the quantum capacitance." The team points out that their supercapacitors show excellent cycle stability with very little degradation over at least 10000 cycles. "At the end point of the electrode lifetime, the CNTs from the used electrode could be recycled to make another new electrode," Rao notes. "The recycled electrode could perform as efficiently as 60% of the original method-a great advantage in terms of sustainability." Another advantage of the roll-to-roll spray-coating process is a significantly lower cost. As the researchers report, the final price of the spray coated CNT electrodes could be reduced by almost 17%, which includes material and production cost. "The industrial collaboration with Cornell Dubilier and Sai Global Technologies is a vital component of this research and is expected to translate the lab-based technology to the market place," note Podila and Rao. "We are thankful to the National Science Foundation for granting an award to undertake such projects which would have lasting impact on the global energy landscape." Source: Nanowerk (

Next Round of Manufacturing Innovation Institutes Include Nanomanufacturing Opportunities

February 27, 2015 - 2:48am
Recent announcements by the federal government identifying the next rounds of Manufacturing Innovation Institutes (MIIs) have selected topics for public-private funding opportunities that potentially provide opportunity for nanomaterials and nanomanufacturing technologies. The selected topics, which include $200M in public-private funding for an Integrated Photonics Institute (IP) (, and $150M a Flexible Hybrid Electronics (FHE) Institute (, each have critical aspects enabled through nanotechnology. Flexible hybrid electronics inherently incorporate printed electronics that involve the processing of various inks containing nanomaterials, such as carbon nanotubes, graphene, or metallic and metal oxide nanoparticles. Similarly integrated photonics exploit innovative materials and processes in order to create integrated optical or photonic devices and systems utilizing nanostructures and nanoscale patterning techniques. Flexible Hybrid Electronics are enabled through innovative manufacturing processes adapted from traditional industry approaches that preserve the full operation of traditional electronic circuits in flexible architectures. The technology demonstrators for manufacturability are intended to exhibit novel flexible form factors that are conformal, bending, stretching, or folding, and address a range of emerging applications in human activity and health monitoring, ubiquitous sensors (i.e.; the Internet of Things), or wearable electronics. The manufacturing institute will address issues including standards, materials, process scale-up, design tools, and advanced manufacturing. The Integrated Photonics Manufacturing Institute will focus on developing an end-to-end photonics ecosystem in the U.S., including domestic foundry access, integrated design tools, automated packaging, assembly and test, and workforce development. The manufacturing innovation institute will serve as a regional hub, bridging the gap between applied research and product development by bringing together companies, universities, and other academic and training institutions and Federal agencies to co-invest in key technology areas that encourage investment and production in the U.S.

New Paper-like Material Could Boost Electric Vehicle Batteries

February 26, 2015 - 7:55am
Researchers create silicon nanofibers 100 times thinner than human hair for potential applications in batteries for electric cars and personal electronicsResearchers at the University of California, Riverside’s Bourns College of Engineering ( have developed a novel paper-like material for lithium-ion batteries. It has the potential to boost by several times the specific energy, or amount of energy that can be delivered per unit weight of the battery. This paper-like material is composed of sponge-like silicon nanofibers more than 100 times thinner than human hair. It could be used in batteries for electric vehicles and personal electronics. The findings were just published in a paper, “Mihri Ozkan (, a professor of electrical and computer engineering, Cengiz S. Ozkan (, a professor of mechanical engineering, and six of their graduate students: Zach Favors, Hamed Hosseini Bay, Zafer Mutlu, Kazi Ahmed, Robert Ionescu and Rachel Ye. The nanofibers were produced using a technique known as electrospinning, whereby 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate (TEOS), a chemical compound frequently used in the semiconductor industry. The nanofibers are then exposed to magnesium vapor to produce the sponge-like silicon fiber structure. Conventionally produced lithium-ion battery anodes are made using copper foil coated with a mixture of graphite, a conductive additive, and a polymer binder. But, because the performance of graphite has been nearly tapped out, researchers are experimenting with other materials, such as silicon, which has a specific capacity, or electrical charge per unit weight of the battery, nearly 10 times higher than graphite. The problem with silicon is that is suffers from significant volume expansion, which can quickly degrade the battery. The silicon nanofiber structure created in the Ozkan’s labs circumvents this issue and allows the battery to be cycled hundreds of times without significant degradation. “Eliminating the need for metal current collectors and inactive polymer binders while switching to an energy dense material such as silicon will significantly boost the range capabilities of electric vehicles,” Favors said. This technology also solves a problem that has plagued free-standing, or binderless, electrodes for years: scalability. Free-standing materials grown using chemical vapor deposition, such as carbon nanotubes or silicon nanowires, can only be produced in very small quantities (micrograms). However, Favors was able to produce several grams of silicon nanofibers at a time even at the lab scale. The researchers’ future work involves implementing the silicon nanofibers into a pouch cell format lithium-ion battery, which is a larger scale battery format that can be used in EVs and portable electronics.Source: UCR Today (

Flexible Nanosensors for Wearable Devices

February 26, 2015 - 7:44am
Researchers from UPM have developed a manufacturing method of aluminum optical nanosensors on versatile substrates that can be used for wearable devices and smart labels. A new method developed at the Institute of Optoelectronics Systems and Microtechnology ( (ISOM) from the Universidad Politécnica de Madrid ( (UPM) will enable the fabrication of optical nanosensors capable of sticking on uneven surfaces and biological surfaces like human skin. This result can boost the use of wearable devices to monitor parameters such as temperature, breath and heart pressure. Besides, it is a low cost technology since they use materials like standard polycarbonate compact disks, aluminum films and adhesive tapes that would facilitate its implementation on the market.Researchers from Semiconductor Devices Group ( idGrupo=260) of ISOM from UPM have not only designed a manufacturing method of optical nanosensors over a regular adhesive tape but also have shown their potential applications. These flexible nanosensors enable us to measure refractive index variations of the surrounding medium and this can be used to detect chemical substances. Besides, they display iridescent colors that can vary according to the viewing and illumination angle, this property facilitates the detection of position variations and surface topography to where they are stuck at a glance. Nanosensors consist of dimensional nanohole arrays (250 nm) which are drilled into an aluminum layer (100 nm thick). In order to cause sensitivity to the surrounding mediums and iridescence effects, these nanostructures confine and disperse light according to the will of the engineer who designs them. The creation method for flexible nanosensors consists, firstly, on manufacturing sensors over a compact disc (CDs) of traditional polycarbonate, and secondly, transferring these sensors to adhesive Scotch tapes by a simple stick-and-peel procedure. This way, the nanosensors go from the CD surface to the adhesive tape (flexible substrate). The stick-and-peel process can be watched at: ( This new technology uses low cost materials such as polycarbonate CDs, aluminum, and regular adhesive tapes. The usage of noble metals to develop these types of sensors is common, but it is difficult mass production due to the high cost. Aluminum is 25,000 times cheaper than gold and has excellent electrical and optical properties. Besides, CD surfaces provide adherence to aluminum that is strong enough to manufacture the sensors over the CDs and weak enough to be transferred to the adhesive tape. This research is led by Dr. Carlos Angulos Barrios, a researcher from ISOM and Professor at the Department of Photonics Technology and Bioengineering ( (TFB) of the School of Telecommunications Engineering (, and also led by Víctor Canalejas Tejero, a PhD student of ISOM. The results were published in the Nanoscale journal ("Compact discs as versatile cost-effective substratesfor releasable nanopatterned aluminium films" (!divAbstract) ).Source: Universidad Politécnica de Madrid (

NanoBCA Interview with Dr. Michael A. Meador, Director, NNCO

February 26, 2015 - 7:32am
NanoBCA was fortunate to engage in a conversation with Dr. Michael A. Meador, the recently appointed Director of the National Nanotechnology Coordination Office (“NNCO”) on February 10, 2015. Dr. Meador, who is technically on loan from NASA to NNCO for this assignment, has a Ph.D. in Chemistry from Michigan State University where he began his career thinking about matter at the molecular scale. While at NASA, Dr. Meador’s efforts included development of “game-changing” technologies from the TRL 4 to TRL 6 levels with a focus on specific technologies such as carbon nanotube based structural composites, nano-based sensors for chemical and biotech detection, among others. The following excerpt, from the NNCO website, outlines Dr. Meador’s impressive credentials and background with regard to nanotechnology. Dr. Meador, chair of NASA’s Nanotechnology Roadmap Team, was instrumental in developing the NASA-wide Nanotechnology Project, and has been responsible for project planning and advocacy, overseeing technical progress, developing external partnerships to advance and transfer technology, coordinating with other nanotechnology related activities within NASA, and interacting with program and senior agency management. He has also played a key role in representing NASA in the NNI’s interagency activities, including co-chairing its Nanomanufacturing, Industry Liaison, and Innovation Working Group. During his long career at NASA, Dr. Meador has held a series of positions with increasing responsibility, including over twenty years as Chief of the Polymers Branch of the Materials Division at NASA Glenn Research Center, where he expanded the research portfolio of the branch from research in high-temperature stable polymers and composites for aircraft engines to include work in battery electrolytes, fuel cell membranes, and nonlinear optical and sensor materials. He also initiated the first nanotechnology program at NASA Glenn. Dr. Meador has been recognized as the NASA Glenn Small Disadvantaged Business Program Technical Advocate of the Year and NASA Small Business Program Technical Personnel of the Year. He has also received the NASA Equal Opportunity Employment Medal for his work to increase the involvement of faculty and students from minority serving institutions in NASA materials research, and last month was awarded the NASA Exceptional Service Medal for leading NASA's Nanotechnology R D activities and representing the agency as a proactive member of the NNI. NanoBCA How long have you been a devotee of the science of nanotechnology? Dr. Meador Dating back to my graduate studies, I have long been aware of the great potential of working with matter at the molecular level. I carried this interest with me to NASA where, as Chief of the Polymers Branch at the Glenn Research Center, I launched one of the first research efforts with NASA focused on the development of nanomaterials technologies. Around 1999 or so, NASA started a long-term relationship with Dr. Richard Smalley of Rice University to focus on scaling up his HiPCO process to produce single wall carbon nanotubes so that we could have a sufficient quantity to evaluate as an additive for polymers. We were fortunate to be a part of that activity. The scale up approach developed under this activity led to Carbon Nanotechnologies Inc. So, I guess you can say that I have been involved with the science of nanotechnology for over 30 years. NanoBCA From a career perspective, what led you to become the Director at NNCO? Dr. Meador Over the course of my career, I have been involved in all aspects of nanotech research and development at a variety of levels within NASA from managing activities in my branch to more recently managing a NASA-wide project in nanotechnology. For the past four years I also served as NASA’s principal representative to the NSET, which gave me a broader perspective on nanotech R D at the Federal government level. It seemed like a very natural progression to aspire to a position like this at NNCO where I could give back, in a leadership role, and utilize my unique career experience with regards to nanotechnology. Personally, it is very exciting for me to be in a position to help push the NNI forward, especially now that it is at a crossroads in that it is coming out of a research and development focused effort to a more defined commercialization effort. NanoBCA The 21st Century Nanotechnology Research and Development Act was signed into law on December 3, 2003. What do you see as the major successes of this Act and what needs to be done going forward? Dr. Meador If not for National Nanotechnology Initiative (“NNI”), which preceded and was then reauthorized by the 21st Century Nanotechnology Research and Development Act, certain industries would not have been created, or at a minimum, would have been created at a much later date. That alone is a very significant accomplishment of the NNI. For instance, the quantum dot industry would not be where it is today if not for the NNI. As you know, Sony announced a new TV recently at the Consumer Electronics Show that will incorporate quantum dots produced by QD Vision, Inc. to enhance picture quality. QD Vision won the 2014 Presidential Green Chemistry Challenge Award ( from the U.S. Environmental Protection Agency, which is the highest domestic honor in the field, recognizing chemical technologies that incorporate the principles of green chemistry into chemical design, manufacture, and use. So, it is clear that the quantum dot industry is making an important impact on our economy, and our environment, and it is an industry that is here to stay. Another example is the carbon nanotube sector, with companies like Nanocomp Technologies, Inc. that are producing materials that not only reduce weight but also greatly improve strength in all sorts of products. Moving forward, we are honing our focus on supporting and expanding success stories like these, particularly as they relate to the commercialization of nanotechnologies. To that end, Dr. Lisa Friedersdorf, NNCO Deputy Director, and I have plans to visit all NSET agencies to talk about their agency’s vision and the NNCO’s vision and to try to establish a plan to more effectively work together to achieve the collective goals of the NNI. We recently visited the NIST Center for Nanoscale Science and Technology, which is truly a world-class facility. This is yet another example of the success of the 21st Century Nanotechnology Research and Development Act and reflects the tangible return on investment from that piece of legislation. So, I think there are a number of examples where nanotechnologies have definitely established a presence in the marketplace, but there is much more that we can do to facilitate the commercialization of nanotechnologies. NanoBCA What is your plan to further impact commercialization? Dr. Meador Success will come from good communications and a focused effort to have NNI agencies work directly with industry to identify and address any roadblocks to commercialization. To that end, the NNCO has initiated a webinar series to highlight problems that industry is facing with regards to nanotech commercialization. This has proven to be a great communications vehicle to provide information, especially to small- and medium- sized business, on topics like insurance and regulations that could help them be more successful in their commercialization efforts. These webinars are scheduled to occur once every other month and are designed to be easily accessible to the broadest audience. NanoBCA One of the challenges that we see regularly at the NanoBCA, is to address the question of whether or not the over $20 billion, that was invested by the 21st Century Nanotechnology Research and Development Act, was worthwhile from a taxpayers’ perspective. Is this a question with which you are confronted? Dr. Meador Yes, this is a very important question that needs to be addressed loudly and clearly and provide a compelling justification for the past and continued investment in the NNI. Fortunately, I have benefitted from sitting on NSET through the critical years and have had a front row seat to witness the impact of this investment. As I mentioned before, there are tangible examples of the return on investment that can be seen in the establishment of new industries and new products which also, not insignificantly, mean new jobs. Also, there has been the establishment of critical new infrastructure, like the NIST Center for Nanoscale Science and Technology. However, it is critically important that the news of these returns be communicated clearly to all stakeholders, which includes the taxpayer, the media and the broader community beyond just those in industry and government who happen to be concerned with nanotechnology as a part of their daily function. That is the challenge that faces us today at NNCO. To address that challenge and to do a better job of communication, NNCO is taking action on several fronts, some of which are quite simple yet very effective. I have already mentioned our webinar series. We are also developing our YouTube channel and reaching out to stakeholders in government and industry to contribute video content that highlights their work. Our goal is to create a buzz about the great potential of nanotechnology commercialization. We are also reaching out directly to students and have established several contests that they can participate in to highlight their research projects (and even art projects). The winners of these contests will be duly recognized at national events. Which brings me to my final point on this matter, which is that we are expanding and improving the quality of our events across the board with the intent of improving the overall impact of our communications. NanoBCA Have you noticed, as we have at NanoBCA, that critics often have misconstrued the literal mandate of the 21st Century Nanotechnology Research and Development Act and perhaps not appreciated that the investment was designed to be on infrastructure and R D, as the name of the Act itself suggests? Dr. Meador Since the inception of the NNI, participating agencies within the Federal government have invested over $20B in nanotechnology related R D. So, I think it is a fair question to ask what the impact of that investment has been on the US economy and job creation. In fact, the President’s Council of Advisors on Science and Technology (“PCAST”) in its last two reviews, and the National Research Council (“NRC”), in its last review, have both called for a clear set of metrics to measure the success of the NNI. We are carefully considering how to develop these metrics by utilizing reports, such as the series of reports over the years by firms such as Lux Research on total revenues generated by nanotech products, as well as other studies which measure the impact of emerging technologies in other ways. Some of the inputs are not just on revenue data, but also on foundational impact such as the establishment of new technologies, sectors and even industries. The bottom line is that we all need to work together to create a better understanding, among the broadest audience possible, of the true impact of nanotechnologies on our society.

Carbon nanotubes show feasibility for practical devices

February 19, 2015 - 4:38am
While carbon nanotubes (CNTs) have long attracted interest for nanoscale electronics, practical deployment of the technology requires a level of device consistency that is still a long way from being achieved. Now researchers at IBM in the US have identified the main source of device variability in CNT transistors and ways of reducing it. In recent years, silicon transistors have been fast approaching their minimum size. Short channel effects and increasing chip power density may halt the trend in constantly decreasing transistor sizes described in 'Moore’s Law'. Fortunately, there is an alternative. "The goal of our research is to develop carbon nanotube transistors into a practical technology that can replace silicon in future generations of high-performance microprocessor chips," says Qing Cao (, who led the IBM research team behind these latest results. Carbon nanotubes have excellent short channel control, a low resistivity between the CNTs and metal contacts, and transport behaviour that allows much lower power consumption for the same on-current density. However where they have fallen short so far is in the uniformity between CNT devices. "Ultimately we want to integrate billions of nanotube transistors into functional circuits," says Cao. "To do this, we need good consistency from one transistor to the next, so they can all work together at the same voltage." Their latest study demonstrates that the device variability does not originate from the nanotubes themselves, and that it may be reduced by improved deposition processes and better materials for the dielectric components.Finding the root of the problem The researchers fabricated hundreds of bottom-gated field-effect transistors, each made from a p-channel single-walled CNT with a 10nm HfO2 layer deposited as the gate dielectric. Systematic experiments with the devices identified the amount of variability from device to device. The measurements also confirmed that variation in carbon nanotube diameter was not a dominant source of variability in device performance. The IBM team then built pairs of devices, where the same nanotube was used as the channel for both transistors. Observations of the performance of device pairs revealed that the dominant source was random, and so likely material-related rather than a systematic process-related contribution. Further analysis indicated that trapped charges fixed at the oxide/air interface were the prime suspect. "I think the results show that it is possible to build practical circuits based on nanotube transistors, but we still need to reduce the variability by several-fold," Cao tells "We have identified the major source as the oxide surface, not anything intrinsic to the nanotubes, so we think we can make it happen with a better fabrication process." He suggests that the variability may be reduced by better control over the nanotube source and the deposition process. "The current nanotube solution isn’t really electronic grade, so we may introduce charges on the oxide during the nanotube deposition process," says Cao. He also suggests that using high quality dielectrics with no free surface near the nanotube may also help. From working to working well Cao describes how far CNT electronics has come in the past few decades. "In the beginning, it was an achievement just to make a few good transistors," he says. The fabrication techniques for these devices are now so advanced that it is possible to fabricate a large enough number of high-quality semiconducting nanotubes to study their random behaviour. He adds, "As it gets closer to becoming a practical technology, the device variability becomes an increasingly important issue." Next the team will work to try and find where the trapped charges come from, and whether they are mainly from dangling bonds at the oxide surface, damage to the oxide during the fabrication process, or residue left by the nanotube solution do that they can eliminate them. Full details are reported in (

Nanotechnology discoveries move from lab to marketplace with CNT fabrication process

February 12, 2015 - 4:50am
A recent agreement between The University of Texas at Dallas and Lintec of America is expected to propel scientific discoveries from the University’s laboratories into the global marketplace and create jobs in North Texas. UT Dallas’ Office of Technology Commercialization ( has licensed to Lintec of America a process developed over several years by Dr. Ray Baughman (, the Robert A. Welch Distinguished Chair in Chemistry, and his colleagues at the University’s Alan G. MacDiarmid NanoTech Institute (, which he directs. The patented process transforms tiny tubes of carbon — 10,000 times thinner than the width of a human hair — into useful large-scale structures, such as sheets and yarns, that are super-strong and extremely light. The carbon nanotube materials have unique thermal, mechanical and electrical properties, making them potentially suitable for use in areas such as wearable electronics, electronic displays, solar panels, sound projectors, batteries and harvesters of waste energy. Lintec of America is a subsidiary of Japan-based Lintec Corporation (, a leading manufacturer of pressure-sensitive adhesives. The company’s advanced materials and industrial products are used in items ranging from electronic devices and computer displays to building and automotive materials. Lintec recently opened the Nano-Science Technology Center ( in Richardson. Less than 5 miles from the UT Dallas campus, it is devoted specifically to the manufacture and commercialization of the carbon nanotube structures. Dr. David E. Daniel, president of UT Dallas, said the whole process — from lab to marketplace — exemplifies how research universities impact the economy and society. “One of the important roles a research university plays in the community is to translate the creativity and human talent developed on campus into the private sector,” he said. “This agreement is an example of UT Dallas doing exactly what it should be doing — fostering an ecosystem of hugely creative faculty who educate and train exceptional students, who then contribute significantly to business and add value to society.” Additionally, two UT Dallas alumni are leading efforts at the Nano-Science Technology Center: Dr. Kanzan Inoue MS’01 PhD’05 is managing director of the facility, and his wife, Dr. Raquel Ovalle-Robles MS’06 PhD’08, is the chief research and intellectual properties strategist. Both worked in the NanoTech Institute with Baughman and Dr. Anvar Zakhidov (, professor of physics. Inoue said proximity to the University and access to its intellectual resources were primary factors in locating the new facility in Richardson. “The Nano-Science Technology Center was created to bridge the gaps between laboratory research, pilot production and ultimately full production processes,” he said. “Individual carbon nanotubes (CNTs) are much lighter, stronger and more thermally conducting than metals or diamond. However, applying CNTs in practical applications requires scalable and controllable processing methods for assembling them into products without losing the unique properties of individual CNTs.”Inoue also said that a critical factor for the controllable device fabrication is the ability to assemble CNTs in different forms, such as free-standing or on a substrate.“The technology developed at UT Dallas delivers an efficient and elegant solution to these key issues,” he said. “The electrically conducting CNT sheets that we can now make are lighter than air, transparent and much stronger per pound than steel.” Lintec has been an industrial affiliate of the NanoTech Institute for many years, and Baughman said the pairing of the UT Dallas science and technology with the company’s manufacturing capabilities was a natural match. “Lintec has expertise in technologies that will be critically important for economically manufacturing carbon nanotube sheets and converting these sheets into a wide range of products,” said Baughman, a National Academy of Engineering member who joined the UT Dallas faculty in 2001 after a 30-year career in private industry. “They invested in UT Dallas technology because they saw potential for valuable end products and because their manufacturing capabilities are particularly well-suited for upscaling the production of these materials to industrial levels.” Baughman said the licensing agreement will enable “teaming” that eliminates barriers between scientific and technological breakthroughs and products, which is an important goal of the NanoTech Institute. “I’m very happy that Lintec decided to open its new facility in Richardson in order to be close to and work collaboratively with our NanoTech Institute, and that they are creating jobs in Texas,” he said. “I’m also delighted that the leaders of this new business venture are UT Dallas alumni from our institute. I know how brilliant they are and look forward to their accomplishments.” Source: The University of Texas at Dallas (

New PEN Inc. Surface Cleaning Product to Redefine Personal Health and Safety

February 6, 2015 - 3:13am
Entry Planned Into $50 Billion Global Cleaning MarketIn direct response to the apparent failure of current cleaners and disinfectants to prevent the spread of illness, PEN Inc. (OTCQB: PENC) is developing a new category of cleaning products intended to clean and fortify surfaces at the nanoscale-level. Unlike traditional harsh pesticide-containing disinfectants, PEN products will incorporate natural elements and sustainable chemistry to keep surfaces safe. The company's aim is to revolutionize the $50 billion global market for industrial and institutional cleaning, which includes lodging, retail outlets, and workplaces. The product is also ideal for the $80 billion global household cleaning market."The news is filled with stories of people being sickened on cruise ship vacations, amusement park visits, and at other public venues," noted Scott E. Rickert, PEN's Chairman, President and CEO. "This PEN product aims to redefine personal health and safety, so consumers can stop worrying about germs and disease every time they touch a restaurant table, airplane armrest, bank ATM machine, or hotel room door." Dr. Rickert added, "Just as important, the patent-pending product will use only safe, sustainable ingredients -- no pesticides or harsh chemicals. In fact the primary ingredient, as listed on the label, is a food additive." Dr. Rickert also addressed the market opportunity. "I expect PEN's first product to expand into a family of products to tackle the problem of safe, healthy surfaces, worldwide. My vision for PEN is to harness the vast potential of nanotechnology to create innovative, breakthrough products for a global marketplace. In PEN we have both the R D expertise and the commercialization experience to begin the process of bringing this product to market." About PEN Inc. (OTCQB: PENC)PEN Inc. (PENC) is a global leader in developing, commercializing and marketing enhanced-performance products enabled by nanotechnology. The company focuses on innovative and advanced product solutions in safety, health and sustainability. For more information about PEN Inc, visit ( Source: PEN Inc. (

The Impact of Nanomanufacturing on the Flexible Electronics Opportunity

January 30, 2015 - 10:17am
The National Academy of Engineering report that was just released in 2014 on “The Flexible Electronics Opportunity ( ” has re-established interest in this growing area which includes strategic opportunities for several future technology platforms, including the Internet of Things, and wearable sensors and systems. The key recommendations are well aligned with strategies, goals and public-private partnerships that have been developing over the past decade. Key recommendations from the report are consistent with the challenges and opportunities that the relevant committees have determined, with the committee recommending the following: The United States should increase funding of basic research related to flexible electronics and augment support for university-based consortia to develop prototypes, manufacturing processes, and products in close collaboration with contributing industrial partners. Consortia, bringing together industry, universities, and various levels of government, should be used as a means of fostering precompetitive applied research in flexible electronics. The United States should establish and support a network of user facilities dedicated to flexible electronics. Where possible, federal efforts to support the growth of competitive flexible electronics industries should leverage state and regional developmental efforts, with the objective of establishing co-located local supply chains and capturing the associated cluster synergies.Agency mission needs should help drive demand for flexible electronics technologies, while lowering costs, improving capabilities, and contributing to the development of a skilled workforce. These recommendations build upon the developments by numerous institutions in establishing industry consortia user facilities to transition the innovations in materials, processes, and integration to industrially meaningful platforms. As such, innovations in nanomaterials and nanomanufacturing processes emerging from NSF Nanoscale Science and Engineering Centers (NSECS) and Nanosystems Engineering Research Centers (NERCs) will play a pivotal role in the innovation cycle to accelerate developments in flexible-hybrid electronics technologies and manufacturing platforms. Complimenting this are the manufacturing demonstration facilities that have been established at various universities as industry user facilities to take advantage of these emerging processes and cutting edge tools that are unavailable elsewhere. Examples include the Center for Advanced Microelectronics Manufacturing (CAMM) at Binghamton University, the Flexible Display Center at Arizona State University, and the Center for Advanced Roll-to-Roll Manufacturing at the University of Massachusetts Amherst. The examples of academic driven public-private partnerships provide leading edge capabilities accessible to industry for acceleration of innovative product development.

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables

January 29, 2015 - 9:19am
New battery technology from the University of Michigan should be able to prevent the kind of fires that grounded Boeing 787 Dreamliners in 2013. The innovation is an advanced barrier between the electrodes in a lithium-ion battery. Made with nanofibers extracted from Kevlar, the tough material in bulletproof vests, the barrier stifles the growth of metal tendrils that can become unwanted pathways for electrical current. A U-M team of researchers also founded Ann Arbor-based Elegus Technologies to bring this research from the lab to market. Mass production is expected to begin in the fourth quarter 2016. "Unlike other ultra strong materials such as carbon nanotubes, Kevlar is an insulator," said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering. "This property is perfect for separators that need to prevent shorting between two electrodes."Lithium-ion batteries work by shuttling lithium ions from one electrode to the other. This creates a charge imbalance, and since electrons can't go through the membrane between the electrodes, they go through a circuit instead and do something useful on the way. But if the holes in the membrane are too big, the lithium atoms can build themselves into fern-like structures, called dendrites, which eventually poke through the membrane. If they reach the other electrode, the electrons have a path within the battery, shorting out the circuit. This is how the battery fires on the Boeing 787 are thought to have started. "The fern shape is particularly difficult to stop because of its nanoscale tip," said Siu On Tung, a graduate student in Kotov's lab, as well as chief technology officer at Elegus. "It was very important that the fibers formed smaller pores than the tip size." While the widths of pores in other membranes are a few hundred nanometers, or a few hundred-thousandths of a centimeter, the pores in the membrane developed at U-M are 15-to-20 nanometers across. They are large enough to let individual lithium ions pass, but small enough to block the 20-to-50-nanometer tips of the fern-structures. The researchers made the membrane by layering the fibers on top of each other in thin sheets. This method keeps the chain-like molecules in the plastic stretched out, which is important for good lithium-ion conductivity between the electrodes, Tung said. "The special feature of this material is we can make it very thin, so we can get more energy into the same battery cell size, or we can shrink the cell size," said Dan VanderLey, an engineer who helped found Elegus through U-M's Master of Entrepreneurship program. "We've seen a lot of interest from people looking to make thinner products." Thirty companies have requested samples of the material. Kevlar's heat resistance could also lead to safer batteries as the membrane stands a better chance of surviving a fire than most membranes currently in use. While the team is satisfied with the membrane's ability to block the lithium dendrites, they are currently looking for ways to improve the flow of loose lithium ions so that batteries can charge and release their energy more quickly. The study, "A dendrite-suppressing solid ion conductor from aramid nanofibers," ( appeared online Jan. 27 in Nature Communications. Source: University of Michigan (

Fully transparent, rollable electronics built with a graphene/carbon nanotube backbone

January 29, 2015 - 9:00am
The coming age of wearable, highly flexible and transparent electronic devices will rely on essentially invisible electronic and optoelectronic circuits. In order to have close to invisible circuitry, one must have optically transparent thin-film transistors (TFTs). In order to have flexibility, one needs bendable substrates. Both flexible electronics and transparent electronics have been demonstrated before, but never rollable electronics that are also fully transparent at the same time. This has now been achieved by a team of researchers in Korea, who have successfully built rollable and transparent electronic devices that are not only lightweight, but also don't break easily. To manufacture flexible electronics, one needs a starting material – the substrate – on which to build-up the device. In order for the final product to be flexible, the substrate of course also has to be flexible. In fact, it is the substrate that determines, to a large extent, the overall flexibility of the final product. So if the substrate is flexible to an extent of being rollable – which can be achieved making it very thin – the final product will also, to some extent, be rollable. Of course, the semiconductors, dielectrics, and metals making up the electronic device, should also be similarly flexible (or soft), otherwise faults will occur. Plastics are the obvious choice for flexible substrates as the substrates are also required to be insulating (nonconductive) in most applications. Other obvious advantages of plastics are that they are lightweight and non-breakable. A team led by Professor Jin Jang, Director of the Department of Information Display ( at Kyung Hee University, has achieved this by overcoming two major challenges associated with the manufacture of flexible electronics: The temperature restriction of plastic substrates (<100°C) and the difficulty of handling flexible electronics during the fabrication process. They reported their findings in ACS Applied Materials Interfaces ("Fully Transparent and Rollable Electronics" ( "To overcome the temperature restriction we chose our plastic substrate to be polyimide (PI), which is a polymer of imide monomers," Jang explains to Nanowerk. "PI has high chemical and heat resistance and when it is colorless, which is the case of this research, it withstands processing temperatures around 300°C." The researchers also chose an amorphous oxide semiconductor – amorphous-indium-gallium-zinc-oxide (a-IGZO) – which assures good device performance even when sputter-deposited at low temperatures. For consistency, they also chose a zinc-based metal, indium-zinc-oxide (IZO), for the metal electrodes – i.e. the gate, source, and drain electrodes of the field-effect transistors making up the electronic devices. "Both the a-IGZO and IZO have large band-gaps, and therefore, are transparent to visible light," says Jang. "As the dielectrics are also transparent and the substrate (PI) is colorless, the final product is see-through with a transmittance of 70% for the full circuit device. The colorless PI (CPI) is 15 µm thick and the thickness of the electronic devices is ∼1 µm, resulting in a total thickness of the fabricated thin-film transistor of only ∼16 µm. Hence, the electronic devices are rollable." In order to deal with the second major challenge – the difficulty of handling flexible electronics during the fabrication process – the researchers used a carrier glass substrate on which the CPI is first spin-coated from solution, and then detached from after device fabrication. Being around 0.7 mm in thickness, the carrier glass is rigid enough to provide mechanical support for the CPI, without which accurate layer registration is impossible during photolithography. This is because standalone plastics substrates can warp, shrink, or bulge at high temperatures. "A rigid carrier substrate is, therefore, a necessity when vacuum processes and photolithography are involved," Jang notes. "However, the way the flexible substrate is attached to the rigid carrier substrate is important as it has to be detached from the carrier substrate after device fabrication. The use of adhesive materials/glues to attach flexible substrates to carrier substrates is not recommended as most adhesives cannot withstand high processing temperatures." An alternative method is to spin-coat the flexible substrate from solution onto the carrier substrate. Although this method avoids the use of adhesive materials, it is very difficult to detach the flexible substrate from the carrier substrate afterwards because bonds between the two have a tendency of strengthening during the fabrication process. "The current solution is to deposit a thin layer such as amorphous-silicon between the flexible substrate and the carrier substrate, which can be evaporated by a laser to release the flexible substrate from the carrier substrate after device fabrication," says Jang. "Given the high cost of installing laser equipment, the complexity of the laser detachment process, and the limitations of the laser beam size, we felt their was a need for a better method." In their research, Jang's team do not use adhesive material or lasers. Neither do they deposit a layer of amorphous-silicon between the carrier glass and the CPI. Instead, they spin coat a mixture of carbon nanotubes (CNT) and graphene oxide (GO) to a thickness of 1 nm from solution onto of the carrier glass before spin coating the CPI. "As the CNT/GO layer has a flake like structure with CNT links, it decreases the area where the CPI contacts the glass, thereby reducing its adhesion to glass," explains Jang. "Inserting the CNT/GO layer also doesn't cost much because only a few drops are required to achieve a thickness around 1 nm." After fabrication, only a small amount of mechanical force is required to detach the CPI from the glass. According to the scientists, the beauty of having the CNT/GO layer is that it bonds stronger with the CPI compared to the glass, such that it remains embedded to the backside of the CPI after detachment – providing mechanical support to the flexible electronics and making the rollable electronics wrinkle-free. Electronic devices built on plastic substrates are prone to electrostatic discharge (ESD) damage because plastics are usually associated with the generation of electrostatic charge. By contrast, the CPI in this present work is ESD-free because localized ESD can be released via the conductive CNT. In their experiments, the team rolled the TFT devices 100 times on a cylinder with radius of 4 mm, without significantly degrading their performance. Integrated circuits also operated without degradation, while being bent to a radius of 2 mm, making these devices suitable for transparent and rollable displays. Source: Nanowerk (

Nanowire clothing could keep people warm — without heating everything else

January 29, 2015 - 8:49am
To stay warm when temperatures drop outside, we heat our indoor spaces — even when no one is in them. But scientists have now developed a novel nanowire coating for clothes that can both generate heat and trap the heat from our bodies better than regular clothes. They report on their technology, which could help us reduce our reliance on conventional energy sources, in the ACS journal Nano Letters ("Personal Thermal Management by Metallic Nanowire-Coated Textile" ( Yi Cui and colleagues note that nearly half of global energy consumption goes toward heating buildings and homes. But this comfort comes with a considerable environmental cost – it's responsible for up to a third of the world's total greenhouse gas emissions. Scientists and policymakers have tried to reduce the impact of indoor heating by improving insulation and construction materials to keep fuel-generated warmth inside. Cui's team wanted to take a different approach and focus on people rather than spaces. The researchers developed lightweight, breathable mesh materials that are flexible enough to coat normal clothes. When compared to regular clothing material, the special nanowire cloth trapped body heat far more effectively. Because the coatings are made out of conductive materials, they can also be actively warmed with an electricity source to further crank up the heat. The researchers calculated that their thermal textiles could save about 1,000 kilowatt hours per person every year — that's about how much electricity an average U.S. home consumes in one month. Source: American Chemical Society (

Wearable Sensor Smooths Path to Long-Term EKG, EMG Monitoring

January 22, 2015 - 6:26am
Researchers from North Carolina State University have developed a new, wearable sensor that uses silver nanowires to monitor electrophysiological signals, such as electrocardiography (EKG) or electromyography (EMG). The new sensor is as accurate as the “wet electrode” sensors used in hospitals, but can be used for long-term monitoring and is more accurate than existing sensors when a patient is moving. Long-term monitoring of electrophysiological signals can be used to track patient health or assist in medical research, and may also be used in the development of new powered prosthetics that respond to a patient’s muscular signals. Electrophysiological sensors used in hospitals, such as EKGs, use wet electrodes that rely on an electrolytic gel between the sensor and the patient’s skin to improve the sensor’s ability to pick up the body’s electrical signals. However, this technology poses problems for long-term monitoring, because the gel dries up – irritating the patient’s skin and making the sensor less accurate. The new nanowire sensor is comparable to the wet sensors in terms of signal quality, but is a “dry” electrode – it doesn’t use a gel layer, so doesn’t pose the same problems that wet sensors do. “People have developed other dry electrodes in the past few years, and some have demonstrated the potential to rival the wet electrodes, but our new electrode has better signal quality than most – if not all – of the existing dry electrodes. It is more accurate,” says Dr. Yong Zhu, an associate professor of mechanical and aerospace engineering at NC State and senior author of a paper describing the work. “In addition, our electrode is mechanically robust, because the nanowires are inlaid in the polymer.” The sensors stem from Zhu’s earlier work to create highly conductive and elastic conductors ( made from silver nanowires, and consist of one layer of nanowires in a stretchable polymer. The new sensor is also more accurate than existing technologies at monitoring electrophysiological signals when a patient is in motion. “The silver nanowire sensors conform to a patient’s skin, creating close contact,” Zhu says. “And, because the nanowires are so flexible, the sensor maintains that close contact even when the patient moves. The nanowires are also highly conductive, which is key to the high signal quality.” The new sensors are also compatible with standard EKG- and EMG-reading devices. “I think these sensors are essentially ready for use,” Zhu says “The raw materials of the sensor are comparable in cost to existing wet sensors, but we are still exploring ways of improving the manufacturing process to reduce the overall cost.” An uncorrected proof of the paper, “Wearable Silver Nanowire Dry Electrodes for Electrophysiological Sensing (,” was published online Jan. 14 in RSC Advances, immediately after acceptance. Lead author of the paper is Amanda Myers, a Ph.D. student at NC State. The paper was co-authored by Dr. Helen Huang, an associate professor in the joint biomedical engineering program at NC State and the University of North Carolina at Chapel Hill.Source: North Carolina State University