KAIST Lab team develops Hyper-stretchable Elastic-Composite Energy Harvester: Applications: Flexible Electronics


Elastic Energy 041415 akaistresearA research team led by Professor Keon Jae Lee of the Department of Materials Science and Engineering at the Korea Advanced Institute of Science and Technology (KAIST) has developed a hyper-stretchable elastic-composite energy harvesting device called a nanogenerator.

Flexible electronics have come into the market and are enabling new technologies like flexible displays in mobile phone, , and the Internet of Things (IoTs). However, is the degree of flexibility enough for most applications? For many flexible devices, elasticity is a very important issue. For example, wearable/biomedical devices and electronic skins (e-skins) should stretch to conform to arbitrarily curved surfaces and moving body parts such as joints, diaphragms, and tendons. They must be able to withstand the repeated and prolonged mechanical stresses of stretching. In particular, the development of elastic energy devices is regarded as critical to establish power supplies in stretchable applications.

Although several researchers have explored diverse stretchable electronics, due to the absence of the appropriate device structures and correspondingly electrodes, researchers have not developed ultra-stretchable and fully-reversible energy conversion devices properly.

Recently, researchers from KAIST and Seoul National University (SNU) have collaborated and demonstrated a facile methodology to obtain a high-performance and hyper-stretchable elastic-composite generator (SEG) using very long silver nanowire-based stretchable electrodes. Their stretchable piezoelectric generator can harvest mechanical energy to produce high power output (~4 V) with large elasticity (~250%) and excellent durability (over 104 cycles). These noteworthy results were achieved by the non-destructive stress- relaxation ability of the unique electrodes as well as the good piezoelectricity of the device components. The new SEG can be applied to a wide-variety of wearable energy-harvesters to transduce biomechanical-stretching energy from the body (or machines) to electrical .

Elastic Energy 041415 akaistresear

Top row shows schematics of hyper-stretchable elastic-composite generator (SEG) enabled by very long silver nanowire-based stretchable electrodes. The bottom row shows the SEG energy harvester stretched by human hands over 200% strain. Credit: KAIST 

Professor Lee said, “This exciting approach introduces an ultra-stretchable piezoelectric generator. It can open avenues for power supplies in universal wearable and biomedical applications as well as self-powered ultra-stretchable electronics.”

This result was published online in the March issue of Advanced Materials, which is entitled “A Hyper-Stretchable Elastic-Composite Energy Harvester.”

Explore further: Nanoengineers develop basis for electronics that stretch at the molecular level

Nano-storage wires


(QDOTS imagesCAKXSY1K 8Nanowerk Spotlight) Nanowires are considered a major  building block for future nanotechnology devices, with great potential for  applications in transistors, solar cells, lasers, sensors, etc. (see for instance: “Nanowires  for the electronics and optoelectronics of the future” and “Nanotechnology explained:  Nanowires and nanotubes”).

Now, for the first time, nanotechnology researchers have  utilized nanowires as a ‘storage’ device for biochemical species such as ATP.   Led by Seunghun Hong, a professor of physics, biophysics and chemical  biology at Seoul National University, the team developed a new nanowire  structure – which they named ‘nano-storage wire’ – which can store and release  biomolecules.

Reporting their findings in the July 16, 2013 online edition of  ACS Nano (“Nano-Storage Wires”), Hong’s group demonstrated  that their nano-storage wire structure can be deposited onto virtually any  substrate to build nanostorage devices for the real-time controlled release of  biochemical molecules upon the application of electrical stimuli.

“Our nano-storage wires are multisegmented nanowires comprised  of three segments and each segment plays a role in extending the applications of  the nanowire,” Hong explains to Nanowerk: “1) the conducting polymer segment  stores biomolecules; 2) the nickel segment allows the utilization of magnetic  fields to drive the nanowires and place them onto a specific location for device  applications; and 3) the gold segment enables a good electrical contact between the deposited nano-storage  wires and the electrodes. The polymer segment is utilized for the controlled  release of ATP molecules. The nickel segment enables the magnetic localization  of nano-storage wires, while the gold segment provides a good electrical contact with electrodes.”

nano-storage wire Left:  Schematics of a nano-storage wire. Right: SEM image of a single nano-storage  wire. The dark, intermediate, and bright regions represent PPy-ATP (conducting  polymer with ATP molecules), nickel, and gold segments, respectively. (Images:  Dr. Seunghun Hong, Seoul National University)    The released biomolecules from such a nanowire-storage system  can be used for instance to control the activity of biosystems. As a proof of concept, the researchers stored  ATP in their nano-storage wires and released it by electrical stimuli, which  activated the motion of motor protein systems. The team also demonstrated flexible nanostorage devices. Here, nano-storage wires were driven by magnetic  fields and deposited onto nickel/gold films on a transparent and flexible  polyimide film. The device  transmitted some light, and it can be easily bent. They also showed that the nanowires could be deposited onto  curved surfaces such as the sharp end of a micropipet.       

     nano-storage wires deposited on tip of a micropipette

SEM  image of nano-storage wires deposited on a micropipet. (Reprinted with  permission from American Chemical Society)   

“Such probe-shaped storage devices can be used for the delivery  of chemicals to individual cells through a direct injection,” says Hong.  “Basically, our results show that nano-storage wires are quite versatile  structures and we  can deposit them onto virtually any structure to create nanoscale devices for  the controlled release of biochemical materials.”

“Nano-storage wires will allow the fabrication of advanced  biochips which can activate or deactivate the activities of biosystems in real  time,” Hong points out. “The activation and deactivation of biosystems such as  biomotors, are controlled by specific biomolecules. In our method, we can  selectively control the biomolecular activities related with ATP or any released  chemical species while leaving other biomolecular activities unaltered.”

Having demonstrated the storage of ATP, the team is now planning  to store other  biomolecules in our nano-storage wires. Examples are drugs to control the  activity of cells and tissues, enzymes to activate specific signal pathways in  biosystems etc. “Eventually, we would like to build an advanced biochip which  can be utilized to control the activities of desired biosystems in real-time,” says Hong.

By Michael Berger. Copyright © Nanowerk

Read more: http://www.nanowerk.com/spotlight/spotid=31619.php#ixzz2buibAVQY

Nanowires: Major Building-block for Nanotechnology Devices: Transistors, Solar Cells, Lasers and More


By Michael Berger. Copyright © Nanowerk

201306047919620(Nanowerk Spotlight) Nanowires are considered a major  building block for future nanotechnology devices, with great potential for  applications in transistors, solar cells, lasers, sensors, etc.

 

*** Read articles explaining how ‘nanowires and nanotubes’ differ from other quantum materials, such as quantum dots, and their potential applications here:

http://www.nanowerk.com/news2/newsid=29945.php

http://www.nanowerk.com/news/newsid=16857.php

 

Now, for the first time, nanotechnology researchers have  utilized nanowires as a ‘storage’ device for biochemical species such as ATP.   Led by Seunghun Hong, a professor of physics, biophysics and chemical  biology at Seoul National University, the team developed a new nanowire  structure – which they named ‘nano-storage wire’ – which can store and release  biomolecules.

Reporting their findings in the July 16, 2013 online edition of  ACS Nano (“Nano-Storage Wires”), Hong’s group demonstrated  that their nano-storage wire structure can be deposited onto virtually any  substrate to build nanostorage devices for the real-time controlled release of  biochemical molecules upon the application of electrical stimuli.

“Our nano-storage wires are multisegmented nanowires comprised  of three segments and each segment plays a role in extending the applications of  the nanowire,” Hong explains to Nanowerk: “1) the conducting polymer segment  stores biomolecules; 2) the nickel segment allows the utilization of magnetic  fields to drive the nanowires and place them onto a specific location for device  applications; and 3) the gold segment enables a good electrical contact between  the deposited nano-storage wires and the electrodes. The polymer segment is  utilized for the controlled release of ATP molecules. The nickel segment enables  the magnetic localization of nano-storage wires, while the gold segment provides  a good electrical contact with electrodes.”

  nano-storage wire Left:  Schematics of a nano-storage wire. Right: SEM image of a single nano-storage  wire. The dark, intermediate, and bright regions represent PPy-ATP (conducting  polymer with ATP molecules), nickel, and gold segments, respectively. (Images:  Dr. Seunghun Hong, Seoul National University)   

The released biomolecules from such a nanowire-storage system  can be used for instance to control the activity of biosystems. As a proof of  concept, the researchers stored ATP in their nano-storage wires and released it  by electrical stimuli, which activated the motion of motor protein systems.   The team also demonstrated flexible nanostorage devices. Here,  nano-storage wires were driven by magnetic fields and deposited onto nickel/gold  films on a transparent and flexible polyimide film. The device transmitted some  light, and it can be easily bent.   They also showed that the nanowires could be deposited onto  curved surfaces such as the sharp end of a micropipet.

nano-storage wires deposited on tip of a micropipette

SEM  image of nano-storage wires deposited on a micropipet. (Reprinted with  permission from American Chemical Society)   

“Such probe-shaped storage devices can be used for the delivery  of chemicals to individual cells through a direct injection,” says Hong.  “Basically, our results show that nano-storage wires are quite versatile  structures and we can deposit them onto virtually any structure to create  nanoscale devices for the controlled release of biochemical materials.”   “Nano-storage wires will allow the fabrication of advanced  biochips which can activate or deactivate the activities of biosystems in real  time,” Hong points out. “The activation and deactivation of biosystems such as  biomotors, are controlled by specific biomolecules.

In our method, we can  selectively control the biomolecular activities related with ATP or any released  chemical species while leaving other biomolecular activities unaltered.”   Having demonstrated the storage of ATP, the team is now planning  to store other biomolecules in our nano-storage wires. Examples are drugs to  control the activity of cells and tissues, enzymes to activate specific signal  pathways in biosystems etc.   “Eventually, we would like to build an advanced biochip which  can be utilized to control the activities of desired biosystems in real-time,”  says Hong.

By Michael Berger. Copyright © Nanowerk

Read more: http://www.nanowerk.com/spotlight/spotid=31619.php#ixzz2apWtDi34

 

Graphene Commercialisation and Applications: Global Industry and Academia Summit


QDOTS imagesCAKXSY1K 8(Nanowerk News) From its high electrical conductivity  and structural strength, graphene has been cited as a “wonder material” with the  potential to revolutionize materials engineering in many different industrial  sectors. While the number of commercial applications for graphene is potentially  unlimited, production scalability must first be established and R&D activity  properly directed to ensure graphene moves out of the lab and into the market.

The Graphene Commercialisation & Applications:  Global Industry & Academia Summit 2013, (25th-26th June, 2013, London),  is the first forum of its kind aimed at establishing the real, commercially  viable industrial applications of graphene, and expediting its role as a  game-changing technology.

With trailblazing companies such as Nokia, Head, Samsung,  Philips, BAE Systems, Sony and Thales, as well as leading academic and research  institutions such as Manchester University, UCLA, Chalmers University, Seoul  National University and Fraunhofer IPA, coming together for the first time to  present their views, this exciting event is a timely opportunity for relevant  stakeholders to evaluate specific industry requirements for graphene, as well as  understanding its’ material capabilities and real world applications.

Senior Business And Scientific Leaders Speaking At The Summit  Include

  • – Jari Kinaret, Professor, Chalmers University and Director, Graphene Flagship  Consortium
  • – James Baker, Managing Director, BAE Systems Advanced Technology Centre
  • – Jani Kivioja, Research Leader, Nokia
  • – Ralf Schwenger, Director R&D Raquetsports, Head Sport
  • – Seungmin Cho, Principal Research Engineer and Group Leader, Samsung Techwin
  • – Byung Hee Hong, Associate Professor, Seoul National University
  • Richard Kaner, Professor of Chemistry, UCLA
  • – Paolo Bondavalli, Head of Nanomaterial Topic, Thales Group
  • – Marcello Grassi, Head of Technology, Spirit AeroSystems Europe
  • – Nuno Lourenco, Head of Technology, UTC Aerospace
  • – York Haemisch, Senior Director Corporate Technologies, Philips Research
  • – Peter Fischer, CTO, Plastic Logic
  • – Antonio Avitabile, Head of Strategic Technology Partnerships, Sony
  • – Ivica Kolaric, Department Head, Fraunhofer IPA
  • – Pradyumna Goli – Research Associate, A.A. Ballandin Nano-Device Laboratory, UC  Riverside
  • – Rahul Nair, Lead Researcher, University of Manchester
  • – Craig Poland, Research Scientist, Institute of Occupational  Medicine

Day One of the Summit will establish graphene’s commercially  viable applications across multiple sectors and the commercialisation roadmap.

Day Two illustrates supply and cost projections as well as  production scalability steps.

Download The Full Agenda And Speaker Faculty  HereThis forum will provide a unique and invaluable opportunity to  gain insights into the opportunities and hindrances presented by graphene. It  will also provide the framework for industry, research and academia to  collaborate in making this revolutionary technological development a market  reality.

Click Here To Register, Saving £200 Per Person By  19th AprilIf you would like more information about joining the exhibition  showcase or require information on group registration discounts, then please  contact the team on +44 (0) 800 098 8489 or email  info@london-business-conferences.co.uk

Read more: http://www.nanowerk.com/news2/newsid=29721.php#ixzz2OfsdEfsv

MIT researchers improve quantum-dot performance


QDOTS imagesCAKXSY1K 8New production method could enable everything from more efficient computer displays to enhanced biomedical testing.

 

 

Quantum dots — tiny particles that emit light in a dazzling array of glowing colors — have the potential for many applications, but have faced a series of hurdles to improved performance. But an MIT team says that it has succeeded in overcoming all these obstacles at once, while earlier efforts have only been able to tackle them one or a few at a time.
Quantum dots — in this case, a specific type called colloidal quantum dots — are tiny particles of semiconductor material that are so small that their properties differ from those of the bulk material: They are governed in part by the laws of quantum mechanics that describe how atoms and subatomic particles behave. When illuminated with ultraviolet light, the dots fluoresce brightly in a range of colors, determined by the sizes of the particles.

QDot Pix 1

 

First discovered in the 1980s, these materials have been the focus of intense research because of their potential to provide significant advantages in a wide variety of optical applications, but their actual usage has been limited by several factors. Now, research published this week in the journal Nature Materials by MIT chemistry postdoc Ou Chen, Moungi Bawendi, the Lester Wolfe Professor of Chemistry, and several others raises the prospect that these limiting factors can all be overcome.
The new process developed by the MIT team produces quantum dots with four important qualities: uniform sizes and shapes; bright emissions, producing close to 100 percent emission efficiency; a very narrow peak of emissions, meaning that the colors emitted by the particles can be precisely controlled; and an elimination of a tendency to blink on and off, which limited the usefulness of earlier quantum-dot applications.

Multicolored biological dyes

For example, one potential application of great interest to researchers is as a substitute for conventional fluorescent dyes used in medical tests and research. Quantum dots could have several advantages over dyes — including the ability to label many kinds of cells and tissues in different colors because of their ability to produce such narrow, precise color variations. But the blinking effect has hindered their use: In fast-moving biological processes, you can sometimes lose track of a single molecule when its attached quantum dot blinks off.
Previous attempts to address one quantum-dot problem tended to make others worse, Chen says. For example, in order to suppress the blinking effect, particles were made with thick shells, but this eliminated some of the advantages of their small size.

The small size of these new dots is important for potential biological applications, Bawendi explains. “[Our] dots are roughly the size of a protein molecule,” he says. If you want to tag something in a biological system, he says, the tag has got to be small enough so that it doesn’t overwhelm the sample or interfere significantly with its behavior.

Quantum dots are also seen as potentially useful in creating energy-efficient computer and television screens. While such displays have been produced with existing quantum-dot technology, their performance could be enhanced through the use of dots with precisely controlled colors and higher efficiency.
Combining the advantages
So recent research has focused on “the properties we really need to enhance [dots’] application as light emitters,” Bawendi says — which are the properties that the new results have successfully demonstrated. The new quantum dots, for the first time, he says, “combine all these attributes that people think are important, at the same time.”

The new particles were made with a core of semiconductor material (cadmium selenide) and thin shells of a different semiconductor (cadmium sulfide). They demonstrated very high emission efficiency (97 percent) as well as small, uniform size and narrow emission peaks. Blinking was strongly suppressed, meaning the dots stay “on” 94 percent of the time.

A key factor in getting these particles to achieve all the desired characteristics was growing them in solution slowly, so their properties could be more precisely controlled, Chen explains. “A very important thing is synthesis speed,” he says, “to give enough time to allow every atom to go to the right place.”
The slow growth should make it easy to scale up to large production volumes, he says, because it makes it easier to use large containers without losing control over the ultimate sizes of the particles. Chen expects that the first useful applications of this technology could begin to appear within two years.

Taeghwan Hyeon, director of the Center for Nanoparticle Research at Seoul National University in Korea, who was not involved in this research, says, “It is very impressive, because using a seemingly very simple approach — that is, maintaining a slow growth rate — they were able to precisely control shell thickness, enabling them to synthesize highly uniform and small-sized quantum dots.” This work, he says, solves one of the “key challenges” in this field, and “could find biomedical imaging applications, and can be also used for solid-state lighting and displays.”
In addition to Chen and Bawendi, the team included seven other MIT students and postdocs and two researchers from Massachusetts General Hospital and Harvard Medical School. The work was supported by the National Institutes of Health, the Army Research Office through MIT’s Institute for Soldier Nanotechnologies, and by the National Science Foundation through the Collaborative Research in Chemistry Program.