The tiniest color picture ever printed

Researchers of ETH Zurich and ETH start-up company Scrona achieve a new world record! They have printed a color picture depicting clown fishes around their sea anemone home. This picture is as tiny as the cross-sectional area of a human hair.

As of today Scrona Ltd. and the ETH Zurich have been announced official World Record Holders for the smallest inkjet-printed colour image. TheGuinness World Records Limited achievement involved the use of the groundbreaking 3D NanoDrip printing technology, invented at ETH Zurich and now commercialized by the ETH spin-off company Scrona.

The printed image measures a minuscule 0.0092 mm2 in area, or 80 µm x 115 µm. That’s about the cross-sectional area of a human hair or the area covered by a single pixel of a retina display. Being so small, the image is totally invisible to the naked eye. To see it, the official witnesses had to use a special microscope.

 

Miniaturized clown fishes

 

The printed image represents a scenery of clown fishes around sea anemones. The colorful little fishes that grow to a size of just about 10 cm (3.9 in.) in real life have been shrunk to approximately 30 µm (0.001 in.). But the fishes do not seem to feel any discomfort in their 3’333-fold miniaturization. Thanks to 24bit color depth in the printout the picturesque scene that depicts their home appears almost as colorful as in reality.

What makes the image appear so lively is the result of so-called quantum-dots (QDs). QDs are nanoparticles that emit light of a very specific color. By tuning their size, this color can be freely engineered, for example from orange to yellow. QDs are known to be very intense in their color appearance, a reason why they currently make a strong debut in flat panel displays.

To create the clown fishes and their cozy sea anemone homes, layers of red, green and blue quantum dots were printed at a resolution of 25’000 DPI, i.e. at an inter-pixel distance of 500 nanometers. To define the 24bit color space the thickness of the deposited quantum dot layers had to be controlled with incredible sub-nanometer precision, at each pixel location.

 

New avenues in display sector

 

Until now, even with cutting-edge semiconductor technology, it was not possible to handle these nanostructured materials with the incredible accuracy that is demonstrated by this Guinness World Records Ltd. achievement. Therefore, the image printed by Scrona and ETH Zurich is not only nice to look at. It highlights new avenues towards the use of nanostructured materials in future electronics and optics, particularly in the display sector.

But before hitting industry, Scrona is now providing a unique opportunity for everyone to experience the technology. Via Kickstarter they offer copies of the true-to-life micro-image, but instead of clown fishes they print the personal content provided by the buyers. In the package is also contained a powerful miniature microscope that is used to render the microscopic pictures visible. This offer is open until 9th of January when their campaign ends.

ETH Zurich

Graphene partnership could deliver next generation of aircraft

Graphene composite-based planes could be a step closer to reality as a result of a partnership between The University of Manchester and a leading Chinese aviation company.

 

Graphene composites could deliver the next generation of aeroplanes

Beijing Institute of Aeronautical Materials（BIAM）has become the latest partner of the National Graphene Institute (NGI), based at the University, to promote the research and development in graphene reinforced aluminium matrix composites areas, and accelerate the application of graphene in the aviation industry and other sectors.

The NGI has around 50 industrial partners working collaboratively on a range of potential applications. The Institute has a number of collaborations with Chinese companies, and in October hosted President Xi Jinping as part of his state visit to the UK.

For this project, BIAM and the University, under the leadership of Professor Robert Young, will exchange expertise and cooperate on the structural characterisation and property testing of graphene reinforced aluminium matrix nanocomposites. 

The projects could result in lighter, stronger and conductive parts for aeroplanes, high speed trains and other industrial equipment to replace traditional materials. With graphene added, the strength of aluminium alloy could be highly improved while retaining its ductile quality. 

The collaboration could improve the technology maturity and accelerate the updating of aeroplane structural materials and functional materials.

In the future, the two parties expect to expand the collaboration on graphene materials. Besides the graphene reinforced aluminium matrix composites, both parties will seek collaboration in areas of graphene energy storage materials, environmental purification materials and information materials.

Dai Shenglong, President of BIAM, said: “Graphene is expected to revolutionize the technology sector. Graphene and its products have unique properties and show wide prospects for applications. 

“BIAM has obtained achievements in the areas of graphene modified structural materials and functional materials, the preparation process and large scale production of graphene nanoflakes and graphene films, and has achieved some extensive application experiences in the aviation industry. 

“Now the collaboration with The University of Manchester will give full play to both sides’ favorable conditions, enhance fundamental research level, improve the technology maturity, and promote together the development of graphene and its products.”

James Baker, Business Director at The University of Manchester, said: “We are delighted to be working with BIAM on collaborative graphene applications.

“Aerospace and other transport areas show great potential for graphene activity and The University of Manchester is leading the way in these areas and many others. Partnering with companies like BIAM gives up the opportunity to accelerate products to market and turn fundamental research into applications of the future.” 

BIAM mainly focuses on the engineering application of graphene modified structural materials and functional materials, and the R&D of graphene related new products and exploitation. 

Manchester National Graphene Institute

Nanostructured germanium for portable photovoltaics and battery electrodes

New approaches for hybrid solar cells

 

Using a new procedure researchers at the Technical University of Munich (TUM) and the Ludwig Maximillians University of Munich (LMU) can now produce extremely thin and robust, yet highly porous semiconductor layers. A very promising material – for small, light-weight, flexible solar cells, for example, or electrodes improving the performance of rechargeable batteries.

The coating on the wafer that Professor Thomas Fässler, chair of Inorganic Chemistry with a Focus on Novel Materials at TU Munich, holds in his hands glitters like an opal. And it has amazing properties: It is hard as a crystal, exceptionally thin and – since it is highly porous – light as a feather.

By integrating suitable organic polymers into the pores of the material, the scientists can custom tailor the electrical properties of the ensuing hybrid material. The design not only saves space, it also creates large interface surfaces that improve overall effectiveness.

“You can imagine our raw material as a porous scaffold with a structure akin to a honeycomb. The walls comprise inorganic, semiconducting germanium, which can produce and store electric charges. Since the honeycomb walls are extremely thin, charges can flow along short paths,” explains Fässler.

The new design: bottom-up instead of top-down

But, to transform brittle, hard germanium into a flexible and porous layer the researchers had to apply a few tricks. Traditionally, etching processes are used to structure the surface of germanium. However, this top-down approach is difficult to control on an atomic level. The new procedure solves this problem.

Together with his team, Fässler established a synthesis methodology to fabricate the desired structures very precisely and reproducibly. The raw material is germanium with atoms arranged in clusters of nine. Since these clusters are electrically charged, they repel each other as long as they are dissolved. Netting only takes place when the solvent is evaporated.

This can be easily achieved by applying heat of 500 °C or it can be chemically induced, by adding germanium chloride, for example. By using other chlorides like phosphorous chloride the germanium structures can be easily doped. This allows the researchers to directly adjust the properties of the resulting nanomaterials in a very targeted manner.

Tiny synthetic beads as nanotemplates

To give the germanium clusters the desired porous structure, the LMU researcher Dr. Dina Fattakhova-Rohlfing has developed a methodology to enable nanostructuring: Tiny polymer beads form three-dimensional templates in an initial step.

In the next step, the germanium-cluster solution fills the gaps between the beads. As soon as stable germanium networks have formed on the surface of the tiny beads, the templates are removed by applying heat. What remains is the highly porous nanofilm.

The deployed polymer beads have a diameter of 50 to 200 nanometers and form an opal structure. The germanium scaffold that emerges on the surface acts as a negative mold – an inverse opal structure is formed. Thus, the nanolayers glitter like an opal.

“The porous germanium alone has unique optical and electrical properties that many energy relevant applications can profit from,” says LMU researcher Dr. Dina Fattakhova-Rohlfing, who, in collaboration with Fässler, developed the material. “Beyond that, we can fill the pores with a wide variety of functional materials, thereby creating a broad range of novel hybrid materials.”

Nanolayers pave the road to portable photovoltaic solutions

“When combined with polymers, porous germanium structures are suitable for the development of a new generation of stable, extremely light-weight and flexible solar cells that can charge mobile phones, cameras and laptops while on the road,” explains the physicist Peter Müller-Buschbaum, professor of functional materials at TU Munich.

Manufacturers around the world are on the lookout for light-weight and robust materials to use in portable solar cells. To date they have used primarily organic compounds, which are sensitive and have relatively short lifetimes. Heat and light decompose the polymers and cause the performance to degrade. Here, the thin but robust germanium hybrid layers provide a real alternative.

Nanolayers for new battery systems

Next, the researchers want to use the new technology to manufacture highly porous silicon layers. The layers are currently being tested as anodes for rechargeable batteries. They could conceivably replace the graphite layers currently used in batteries to improve their capacity.

The research was funded by the “Solar Technologies Go Hybrid” program of the Bavarian State Ministry of Science, in the context of the excellence cluster “Nanosystems Initiative Munich (NIM), the German Research Foundation (DFG) and the Center for Nanosciences (CeNS).

Publication:

Zintl Clusters as Wet Chemical Precursors for Germanium Nanomorphologies with Tunable Composition; Manuel M. Bentlohner, Markus Waibel, Patrick Zeller, Kuhu Sarkar, Peter Müller-Buschbaum, Dina Fattakhova-Rohlfing, Thomas F. Fässler
Angewandte Chemie, online 03.12.2015 – DOI: 10.1002/ange.201508246

Technical University of Munich

http://www.nanotechnologyworld.org/?draft=true#!Nanostructured-germanium-for-portable-photovoltaics-and-battery-electrodes/c89r/56659a740cf28314431b0321 

Scientists grow organic semiconductor crystals vertically for first time

UCLA-led breakthrough could literally reshape solar cells and electronic devices

 

Our smartphones, tablets, computers and biosensors all have improved because of the rapidly increasing efficiency of semiconductors.

Since the turn of the 21st century, organic, or carbon-based, semiconductors have emerged as a major area of interest for scientists because they are inexpensive, plentiful and lightweight, and they can conduct current in ways comparable to inorganic semiconductors, which are made from metal-oxides or silicon.

Now, materials scientists from the California NanoSystems Institute at UCLA have discovered a way to make organic semiconductors more powerful and more efficient.

Their breakthrough was in creating an improved structure for one type of organic semiconductor, a building block of a conductive polymer called tetraaniline. The scientists showed for the first time that tetraaniline crystals could be grown vertically.

The advance could eventually lead to vastly improved technology for capturing solar energy. In fact, it could literally reshape solar cells. Scientists could potentially create “light antennas” — thin, pole-like devices that could absorb light from all directions, which would be an improvement over today’s wide, flat panels that can only absorb light from one surface.

The study, led by Richard Kaner, distinguished professor of chemistry and biochemistry and materials science and engineering, was recently published online by the journal ACS Nano.

The UCLA team grew the tetraaniline crystals vertically from a substrate, so the crystals stood up like spikes instead of lying flat as they do when produced using current techniques. They produced the crystals in a solution using a substrate made of graphene, a nanomaterial consisting of graphite that is extremely thin — measuring the thickness of a single atom. Scientists had previously grown crystals vertically in inorganic semiconducting materials, including silicon, but doing it in organic materials has been more difficult.

Tetraaniline is a desirable material for semiconductors because of its particular electrical and chemical properties, which are determined by the orientation of very small crystals it contains. Devices such as solar cells and photosensors work better if the crystals grow vertically because vertical crystals can be packed more densely in the semiconductor, making it more powerful and more efficient at controlling electrical current.

“These crystals are analogous to organizing a table covered with scattered pencils into a pencil cup,” said Yue “Jessica” Wang, a former UCLA doctoral student who now is a postdoctoral scholar at Stanford University and was the study’s first author. “The vertical orientation can save a great deal of space, and that can mean smaller, more efficient personal electronics in the near future.”

Once Kaner and his colleagues found they could guide the tetraaniline solution to grow vertical crystals, they developed a one-step method for growing highly ordered, vertically aligned crystals for a variety of organic semiconductors using the same graphene substrate.

“The key was deciphering the interactions between organic semiconductors and graphene in various solvent environments,” Wang said. “Once we understood this complex mechanism, growing vertical organic crystals became simple.”

Kaner said the researchers also discovered another advantage of the graphene substrate.

“This technique enables us to pattern crystals wherever we want,” he said. “You could make electronic devices from these semiconductor crystals and grow them precisely in intricate patterns required for the device you want, such as thin-film transistors or light-emitting diodes.”

The paper’s other authors were UCLA graduate students James Torres, Shan Jiang and Michael Yeung; Adam Stieg, associate director of shared resources at CNSI and the scientific director of the Nano and Pico Characterization Lab; Yves Rubin, UCLA professor of chemistry and biochemistry; and Xiangfeng Duan, UCLA professor of chemistry and biochemistry. Co-author Santanu Chaudhuri is a principal research scientist at the Illinois Applied Research Institute at University of Illinois at Urbana–Champaign.

UCLA

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Light as a Balloon, Tough as Metal: new type of material created

A group of Chinese scientists from Shanghai Institute of Ceramics at the Chinese Academy of Sciences have developed a foam like super material which is composed of tiny graphene tubes and can sustain a force of 40,000 times its own weight without getting distorted. The most important thing about the material is that it is as light as a balloon and strong as metal.

The deepest point on the planet is the Mariana Trench in the Pacific Ocean. The deepest point is almost 11 kilometers below the ocean surface. There have been a couple of instances when any man-made vessel has been able to reach such depth where the pressure reaches 6,577 kg per sq. inch. Imagine a substance that can easily sustain such crushing forces.

The foam-like material created by the scientists is said to be 207 times stronger than steel, can withstand a weight 40,000 times of its own without bending.

The Graphene-based material has a cellular structure that will have the same stability and toughness of diamond. The cellular structure of diamond is what affords it the toughness it is known to exhibit.

The material can be used for a variety of domains which includes security and military hardware. The material is an ideal material for construction of making bulletproof vests and even tanks and aircrafts.

Tanks are made of a material that is strong and at the same time able to withstand shocks from projectile and missiles. Bulletproof vests can have an extra lining of this material so that it can absorb shocks from bullets and protect the wearer.

In fact, this wonder material is believed to withstand more shocks than any other graphene material. It could be compressed to 5% its original size over 1000 times, but it could regain its original form with ease.

The scientists from Chinese Academy of Sciences have published their research work in a journal Advanced Materials.

Chinese Academy of Sciences

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Designed defects in liquid crystals can guide construction of nanomaterials

Imperfections running through liquid crystals can be used as miniscule tubing, channeling molecules into specific positions to form new materials and nanoscale structures, according to engineers at the University of Wisconsin-Madison. The discovery could have applications in fields as diverse as electronics and medicine.

"By controlling the geometry of the system, we can send these channels from any one point to any other point," says Nicholas Abbott, a UW-Madison professor of chemical and biological engineering. "It's quite a versatile approach."

Nicholas Abbott

So far, Abbott and his collaborators at UW-Madison's Materials Research Science and Engineering Center (MRSEC) have been able to assemble phospholipids — molecules that can organize into layers in the walls of living cells — within liquid crystal defects.

Their technique may also be useful for assembling metallic wires and various semiconducting structures vital to electronics. There's also potential for mimicking the selective abilities of a membrane, designing a defect so that one type of molecule can pass through while others can't.

"This is an enabling discovery," Abbott says. "We're not looking for a specific application, but we're showing a versatile method of fabrication that can lead to structures you can't make any other way."

The researchers — including UW-Madison graduate students Xiaoguang Wang, Daniel S. Miller and Emre Bukusoglu, and Juan J. de Pablo, a former UW-Madison engineering professor now at the University of Chicago — published details of their advance this week in the journal Nature Materials.

For about 20 years, Abbott's research has examined the surfaces of soft materials, including liquid crystals — a particular phase of matter in which liquid-like materials also exhibit some of the molecular organization of solids.

"We've done a lot of work in the past at the interfaces of liquid crystals, but we're now looking inside the liquid crystal," he says. "We're looking at how to use the internal structure of liquid crystals to direct the organization of molecules. There's no prior example of using a defect in a liquid crystal to template molecular organization."

When the researchers manipulate the geometry of a liquid crystalline system, a variety of different defects can result. Abbott's group assembled liquid crystals with defects shaped like ropes or lines they call "disclinations," that formed templates they could fill with amphiphilic (water- and fat-loving) molecules.

Then they can link together assemblies of molecules and remove the liquid crystal templates, leaving behind the amphiphilic building blocks in a lasting, nanoscale structure.

The research is an example of how liquid crystal research is taking us from the nano to macro world, says Dan Finotello, program director at the National Science Foundation, which funds the MRSEC.

"It is also an exquisite demonstration of MRSEC programs' high impact," Finotello says. "MRSECs bring together several researchers of varied experience and complementary expertise who are then able to advance science at a considerably faster rate."

University of Wisconsin

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