EV Group Introduces Roll-To-Roll Nanoimprint Lithography System For Biomedical, Optical And Flexible Electronics Applications


Electronics-research-001(Nanowerk News) EV Group (EVG), a leading supplier of  wafer bonding and lithography equipment for the MEMS, nanotechnology and  semiconductor markets, today introduced the EVG®570R2R—the industry’s first  roll-to-roll thermal nanoimprint lithography (NIL) tool.

 

 

Jointly developed with  the Industrial Consortium on Nanoimprint (ICON), helmed by A*A*STAR‘s Institute of  Materials Research and Engineering (IMRE), the EVG570R2R utilizes hot embossing  to mass-produce films and surfaces with micro- and nanometer-scale structures  for a variety of medical, consumer and industrial applications, including  micro-fluidics, plastic electronics and photovoltaics.  The first system has  been installed in IMRE’s Singapore facility, where it will be used by IMRE to  conduct industrial research on the potential uses for large-scale nanoimprint  patterning, as well as by EV Group for product demonstrations with prospective  customers.

roll-to-roll thermal nanoimprint lithography tool
EV  Group unveils the industry’s first roll-to-roll thermal nanoimprint lithography  tool, the EVG®570R2R, which mass-produces films and surfaces with micro- and  nanometer-scale structures for a variety of medical, consumer and industrial  applications, including micro-fluidics, plastic electronics and photovoltaics.
Roll-to-roll nanoimprint technology is an attractive approach to  manufacturing micro- and nano-scale patterns due to its low cost, continuous  high throughput and large-area patterning capabilities.  Hot embossing, which is  one method of implementing roll-to-roll patterning, is particularly well suited  for devices used in biological and medical applications due to its low cost,  high throughput, material flexibility and monolithic approach.  By partnering  with IMRE, EVG has been able to leverage IMRE’s core competencies in materials  science with its own expertise in temperature embossing and pressure uniformity  to develop the EVG570R2R, whose innovative imprint module design provides  excellent temperature and pressure uniformity for micro- and nanoscale  patterning on a broad range of materials.
“While roll-to-roll nanoimprint lithography holds much promise  in enabling a variety of new applications, previous efforts to develop the  technology lacked a holistic approach,” stated Professor Andy Hor Tzi Sum,  executive director of IMRE.  “As part of this new ICON project, IMRE is bringing  together technology innovators from across the ecosystem to help drive this  technology toward commercialization.  Companies like EV Group have been  instrumental in building the foundational tools and solutions needed to make  roll-to-roll nanoimprint a viable manufacturing process.”
The EVG570R2R is the latest addition to EV Group’s extensive  suite of nanoimprint products, which also include the EVG®770 automated NIL  stepper, the EVG®750 automated hot embossing system, the IQ  Aligner® automated  UV-NIL and u-CP systems, the EVG®510HE and EVG®520HE semi-automated hot  embossing systems, and the EVG®620 and EVG®6200 automated UV-NIL systems.
Paul Lindner, EV Group’s executive technology director,  commented, “With the EVG570R2R, EV Group now offers the largest imprint product  portfolio to support a wide variety of applications, including medical,  point-of-care diagnostics, flexible electronics, displays, solar, architectural  glass and other structured films, biotechnology, security and optics.  We are  very proud of this particular development and working with IMRE and the ICON  organization.  EVG is once again laser focused on turning its R&D efforts  into world-class production-ready solutions, and we look forward to seeing the  results.”
About EV Group
EV Group (EVG) is a leading supplier of equipment and process  solutions for the manufacture of semiconductors, microelectromechanical systems  (MEMS), compound semiconductors, power devices and nanotechnology devices.  Key  products include wafer bonding, thin-wafer processing, lithography/nanoimprint  lithography (NIL) and metrology equipment, as well as photoresist coaters,  cleaners and inspection systems.  Founded in 1980, EV Group services and  supports an elaborate network of global customers and partners all over the  world.  More information about EVG is available at http://www.EVGroup.com.
Source: EV Group (press release)

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Self-Healing Solar Cells


Large Solar panelsTo understand how solar cells heal themselves, look no further than the nearest tree leaf or the back of your hand.

The “branching” vascular channels that circulate life-sustaining nutrients throughout leaves and hands serve as the inspiration for solar cells that can restore themselves efficiently and inexpensively.

 

 

In a new paper, North Carolina State University researchers Orlin Velev and Hyung-Jun Koo show that creating solar cell devices with channels that mimic organic vascular systems can effectively reinvigorate solar cells whose performance deteriorates due to degradation by the sun’s ultraviolet rays. Solar cells that are based on organic systems hold the potential to be less expensive and more environmentally friendly than silicon-based solar cells, the current industry standard.

 

The design of NC State's regenerative solar cell mimics nature by use of microfluidic channels.

The nature-mimicking devices are a type of dye-sensitized solar cells (DSSCs), composed of a water-based gel core, electrodes, and inexpensive, light-sensitive, organic dye molecules that capture light and generate electric current. However, the dye molecules that get “excited” by the sun’s rays to produce electricity eventually degrade and lose efficiency, Velev says, and thus need to be replenished to reboot the device’s effectiveness in harnessing the power of the sun.

Organic material in DSSCs tends to degrade, so we looked to nature to solve the problem,” Velev said. “We considered how the branched network in a leaf maintains water and nutrient levels throughout the leaf. Our microchannel solar cell design works in a similar way. Photovoltaic cells rendered ineffective by high intensities of ultraviolet rays were regenerated by pumping fresh dye into the channels while cycling the exhausted dye out of the cell. This process restores the device’s effectiveness in producing electricity over multiple cycles.”

Velev, Invista Professor of Chemical and Biomolecular Engineering at NC State and the lead author of a paper in Scientific Reports describing the research, adds that the new gel-microfluidic cell design was tested against other designs, and that branched channel networks similar to the ones found in nature worked most effectively.

Study co-author Dr. Hyung-Jun Koo is a former NC State Ph.D. student who is now a postdoctoral researcher at the University of Illinois. The study was funded by the National Science Foundation and the U.S. Department of Energy.

Koo and Velev reported earlier a new type of biomimetic hydrogel solar cell.

– kulikowski –

Note to editors: The abstract of the paper follows.

“Regenerable Photovoltaic Devices with a Hydrogel-Embedded Microvascular Network”

Authors: Hyung-Jun Koo and Orlin D. Velev, NC State University

Published: Aug. 5, 2013, in Scientific Reports

DOI: 10.1038/srep02357

Abstract: Light-driven degradation of photoactive molecules could be one of the major obstacles to stable long term operation of organic dye-based solar light harvesting devices. One solution to this problem may be mimicking the regeneration functionality of a plant leaf. We report an organic dye photovoltaic system that has been endowed with such microfluidic regeneration functionality. A hydrogel medium with embedded channels allows rapid and uniform supply of photoactive reagents by a convection-diffusion mechanism. A washing-activation cycle enables reliable replacement of the organic component in a dye-sensitized photovoltaic system.

 

Release Date: 08.07.13 Filed under Releases

 

 

Nanopillars and a Disinfected World


QDOTS imagesCAKXSY1K 8The microbial world is ever-present and unrelenting.  The enormity of it is hard to fathom, with facts like ‘there are 10  bacterial cells living in or on you for every one cell that is you’  and ‘estimates suggest there are five million trillion trillion bacteria  on this planet’, that’s hard to predict, it may be plus or minus  a few. Controlling our interactions with this world may seem futile  but we do so everyday.

750px-Algae_and_bacteria_in_Scanning_Electron_Microscope_magnification_2000xBacteria come in all shapes, sizes and types with  some beneficial, others pathogenic and others insignificant (to our  health at least) so being able to regulate our microbial environments  is vitally important. It is to our advantage to foster the beneficial  species and inhibit the species that are less so. We do this every day  by eating certain food, taking certain supplements and, of course, enlisting  the support of drugs and medications, all of which affect the bacteria  inside and on you. Controlling our own microbial microenvironments is  only part of the story though, what about controlling the bacterial  reservoirs we interact with, the tables, handrails, chairs, the surfaces  of our lives? That employs a whole range of other techniques.

Disinfecting a surface can be done in many ways. By  far the most common are the chemical disinfectant sprays and aerosols.  Disinfectant sprays contain active ingredients that effect either the  walls or metabolism of microbes. By disturbing the stability of bacterial  membranes or metabolic pathways they kill indiscriminately but they  have their drawbacks. Many bacteria sporulate and disinfectants are useless against them and to differences in virus  and fungus make-up they can also be less effective against these agents  too, but, most importantly, are often toxic.

Toxicity is not the only problem. Spreading these  agents around can cause a range of issues and as we have seen with antibiotics,  resistance to disinfecting agents can and is occurring. That ‘kills  99.9%’ label hides the problem of the 0.1% that survive, divide, and  pass on the ability to survive the disinfectant attack to their daughters.

An alternative to disinfectants is UV light. UV light  is very good at disinfecting solid surfaces. UV light mutates the nucleic  acids in DNA, which results in an inability to divide easily or continue  making important proteins. Having a surface disinfection system that  works by inducing mutations has its own problems and the known ability  of UV to cause mutations in any DNA means that this method has the potential  to cause cancers long term.

There is another problem shared by systems such as  spray disinfectants and UV lights, a reliance on continuing human involvement.  What would be really great would be a disinfection system that is included  as part of a products manufacture. Such systems exist and are part of  a growing field of ‘passive antimicrobial agents’.

Many metals are known to possess antimicrobial properties.  Products made with silver, despite there short shelf life, are thought  to be effective, although there are conflicting data on this. A particular  form of silver (a chelated form called silver dihydrogen citrate, SDC)  is thought to work in two main ways, by interfering with the way membrane  proteins work and by denaturing DNA after being taken-up by the bacterial  cells.

 

Another example is surfaces containing copper alloys.  Copper, in much the same way as silver, can interrupt protein form and  function as well as being able to interact with lipids and other cellular  architecture and by doing so inhibit bacterial population growth. Copper  also acts as a potent catalyst of redox reactions and so acts to increase  free radicals and oxidative stress.

 

With more support for copper than silver it seems  like the best way to go but copper is expensive. Reserves are dwindling  and some predictions suggest we could run out of economically viable  reserves within 60 years. The major reservoir of copper now lies in  recycled materials and these are increasingly re-used in electronics.  Dumping copper into surfaces is perhaps not the best use of it.

Passive antimicrobial surfaces have a new hero. Recent  work from Swinburne University in Australia has found that ‘nanopillars’  on the surface of the wings of an insect-like locust (the clanger cicada)  give it the ability to fight bacterial colonisation. The arrangement  of these hexagonal pillars is much like a bed of nails, as a bacterial  cell lies on top of them it spreads out and the pillars push against  the membrane. The parts of the membrane that sag between the pillars  are stretched and when weakened the bacterial membrane cannot keep the  liquid insides of the bacteria, well, inside. As the inside leaks out  the bacterial cell dies.

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This arrangement is mechanical, not chemical, and  so is completely non-toxic and safe for humans. Finding a cheap and  effective way to build these structures on surfaces would result in  a microenvironment imperceptible to us but lethal to bacteria that happen  upon it and inducing this microenvironment on hospital surfaces like  door handles, bed rails and tables can help prevent hospital-acquired  infections which are a huge issue in hospitals all around the world.  Being passive means it takes the risk of not quite cleaning that spot  out of the equation and being mechanical means it need never be replaced.

As the research pointed out, the more rigid a bacterial  membrane (rigidity was increased as a result of microwaving them) the  less effective this approach as the membrane doesn’t sag between the  pillars. This suggests that there may be a selectable trait for evolving  around this strategy long-term but as it is the only mechanical antimicrobial  surface structure to be observed so far it presents an interesting opportunity  to think differently about disinfection.

About the Author: Dr James Byrne has a PhD in Microbiology and works as a science communicator at the Royal Institution of Australia (RiAus), Australia’s unique national science hub, which showcases the importance of science in everyday life. Follow on Twitter @JB_blogs.

Self-assembling Solar-harvesting Films Reveals New Low-Cost Tool for 3D Circuit Printing


4 March 2013 (created 4 March 2013)

QDOTS imagesCAKXSY1K 8Scientists from Imperial College London, working at the Institut Laue-Langevin, have presented a new way of positioning nanoparticles in plastics, with important applications in the production of coatings and photovoltaic material that harvest energy from the sun.  The study used neutrons to understand the role that light – even ambient light – plays in the stabilisation of these notoriously unstable thin films. As a proof of concept the team have shown how the combination of heat and low intensity visible and UV light could in future be used as a precise, low-cost tool for 3D printing of self-assembling, thin-film circuits on these films.
Thin films made up of long organic molecule chains called polymers and fullerenes (large football-shaped molecules composed entirely of carbon) are used mainly in polymer solar cells where they emit electrons when exposed to visible or ultraviolet sun rays. These so-called photovoltaic materials can generate electrical power by converting solar radiation into direct electrical current.
Polymer solar cells are of significant interest for low-power electronics, such as autonomous wireless sensor networks used to monitor everything from ocean temperature to stress inside a car engine. These fullerene-polymer mixtures are particularly appealing because they are lightweight, inexpensive to make, flexible, customisable on the molecular level, and relatively environmentally-friendly.
However current polymer solar cells only offer about one third of the efficiency of other energy harvesting materials, and are very unstable.
In order to improve science’s understanding of the dynamics of these systems and therefore their operational performance, the team carried out neutron reflectometry experiments at the ILL, the world’s flagship centre for neutron science, on a simple model film made up of pure fullerenes with a flexible polymer. Neutron reflectometry is a non-destructive technique that allows you to ‘shave’ layers off these thin films to look at what happens to the fullerenes and the polymers separately, at atomic scale resolution, throughout their depth.
Whilst previous theories suggested that thin film stabilisation was linked to the formation of an expelled fullerene nanoparticle layer at the substrate interface, neutron reflectometry experiments showed that the carbon “footballs” remain evenly distributed throughout the layer. Instead, the team revealed that the stabilisation of the films was caused by a form of photo-crosslinking of the fullerenes. The process imparts greater structural integrity to films, which means that ultrathin films, (down to 10000 times smaller than a human hair) readily become stable with trace amounts of fullerene.
The implications of this finding are significant, particularly in the potential to create much thinner plastic devices which remain stable, with increased efficiency and lifetime (whilst the smaller amount of material required minimises their environmental impact).

The light sensitivity also suggests a unique and simple tool for imparting patterns and designs onto these notoriously unstable films. To prove the concept the team used a photomask to spatially control the distribution of light and added heat. The combination causes the fullerenes to self-assemble into well-defined connected and disconnected patterns, on demand, simply by heating the film until it starts to soften. This results in spontaneous topography and may form the basis of a low-cost tool for 3D printing of thin film circuits.

Other potential applications could include patterning of sensors or biomedical scaffolds.
In the future, the team is looking to apply its findings to conjugated polymers and fullerene derivatives, more common in commercial films, and industrial thin film coatings.

Source: From A neutron investigation into self-assembling solar-harvesting films reveals new low-cost tool for 3D circuit printing. This work is detailed in the paper “Patterning Polymer–Fullerene Nanocomposite Thin Films with Light” by Him Cheng Wong, Anthony M. Higgins, Andrew R. Wildes, Jack F. Douglas, João T. Cabral.

Wipe-On Nanocoating to Exceed Automotive OEM Specs


QDOTS imagesCAKXSY1K 8(Nanowerk News) Imagine for a moment a world were  automotive plastics never fade, a self-cleaning wheel that resists brake dust, a  self-cleaning tire that looks new for life, or a fiberglass boat that resists  fading for life. These and other amazing benefits are now possible due to 10  years of research & development in nanotechnology.
According to Nanovere Technologies Chairman & Chief  Technology Officer Thomas Choate, “Nanovere is pleased to introduce the world’s  first Wipe-On clear nanocoating to exceed automotive OEM specifications. The  product is named Vecdor Nano-Clear®. What’s most unique about Nano-Clear® is the  ability to permanently restore original color, gloss and surface hardness back  into oxidized textured plastics, highly oxidized fiberglass and highly oxidized  paint surfaces while reducing surface maintenance by 60%.”
Nanotechnology can be described as the science of molecular  engineering. Nanovere Technologies has pioneered proprietary 3D nanostructured  coatings at the molecular level since 2003. Nano-Clear® forms a “highly  crosslink dense film with extreme scratch resistance, chemical resistance, UV  resistance, remarkable flexibility and self-cleaning properties including water,  oil, ice and brake-dust repellency.”
The application potential for Nano-Clear® Wipe-On nanocoating  includes automotive textured plastics, aluminum and steel wheels, tires,  oxidized paint surfaces including heavy duty equipment, boat hulls, aluminum  siding, outdoor metal furniture, air conditioner housings, etc.
Vecdor nanocoatings have been tested and validated by some of  the world’s leading OEM companies including Boeing, BMW, Accuride Truck Wheels  and many others to outperform leading OEM clear coatings;
  • 53%  higher scratch resistance: 4H pencil hardness
  • 476%  higher chemical resistance over nearest competitor: 500+ MEK rubs
  • 60%  reduced surface maintenance: water, oil and ice repellency
  • 94%  gloss retention even after 5 years
Nanovere is currently establishing global distribution networks&nbsp; for Vecdor Nano-Clear®. Interested parties may contact Nanovere directly at&nbsp; alliances@nanovere.com or call us at&nbsp; (810)&nbsp; 227-0077 . To learn&nbsp; more about Nanovere or nanotechnology, please visit us at&nbsp; http://www.nanocoatings.com or email question@nanovere.com.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Nanovere Technologies, LLC. specializes in the research &  development of first-to-market nanocoatings and licensing of 3D nanostructured  coating polymers to a world leading paint manufacture. Nanovere Technologies was  founded in 2003 and invented the core polymers and nanocoatings which currently  represent 11 global patents pending.
Source: Nanovere (press  release)

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Photoluminescent SiC tetrapods


qdot-imagescaf658qe-4.jpgAndrew P. Magyar, Igor Aharonovich, Mor Baram, Evelyn L. Hu

(Submitted on 29 Nov 2012)

Photoluminescent SiC tetrapods

Abstract: Recently, significant research efforts have been made to develop complex nanostructures to provide more sophisticated control over the optical and electronic properties of nanomaterials. However, there are only a handful of semiconductors which allow control over their geometry via simple chemical processes. Here, we present a molecularly seeded synthesis of a complex nanostructure, SiC tetrapods, and report on their structural and optical properties. The SiC tetrapods exhibit narrow linewidth photoluminescence at wavelengths spanning the visible to near infrared spectral range. Synthesized from low-toxicity, earth abundant elements, these tetrapods are a compelling replacement for technologically important quantum optical materials that frequently require toxic metals such as Cd and Se. This new, previously unknown geometry of SiC nanostructures is a compelling platform for biolabeling, sensing, spintronics and optoelectronics.

Comments: 14 pages, 4 figures
Subjects: Materials Science (cond-mat.mtrl-sci)
Cite as: arXiv:1211.6801 [cond-mat.mtrl-sci]
(or arXiv:1211.6801v1 [cond-mat.mtrl-sci] for this version)

Submission history

From: Andrew Magyar [view email] [v1] Thu, 29 Nov 2012 02:50:49 GMT  (1877kb,D)