Liquid Storage Of The Sun’s Power

Researchers at Chalmers University of Technology in Sweden have demonstrated efficient solar energy storage in a chemical liquid. The stored energy can be transported and then released as heat whenever needed. ​Many consider the sun the energy source of the future. But one challenge is that it is difficult to store solar energy and deliver the energy ‘on demand’.

The research team from Chalmers University has shown that it is possible to convert the solar energy directly into energy stored in the bonds of a chemical fluid – a so-called molecular solar thermal system. The liquid chemical makes it possible to store and transport the solar energy and release it on demand, with full recovery of the storage medium. The process is based on the organic compound norbornadiene that upon exposure to light converts into quadricyclane.
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The technique means that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it,’ says Professor Kasper Moth-Poulsen, who is leading the research team. ‘Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80 percent of the incoming sunlight.’

The research project was initiated at Chalmers more than six years ago and the research team contributed in 2013 to a first conceptual demonstration. At the time, the solar energy conversion efficiency was 0.01 percent and the expensive element ruthenium played a major role in the compound. Now, four years later, the system stores 1.1 percent of the incoming sunlight as latent chemical energy – an improvement of a factor of 100. Also, ruthenium has been replaced by much cheaper carbon-based elements.

We saw an opportunity to develop molecules that make the process much more efficient,’ says Moth-Poulsen. ‘At the same time, we are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation.’

The research is presented on the cover of the scientific journal Energy & Environmental Science.

Source: http://www.reuters.com/
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Carbon Nanotubes Self-Assemble Into Tiny Transistors

Carbon nanotubes can be used to make very small electronic devices, but they are difficult to handle. University of Groningen (Netherlands) scientists, together with colleagues from the University of Wuppertal and IBM Zurich, have developed a method to select semiconducting nanotubes from a solution and make them self-assemble on a circuit of gold electrodes. The results look deceptively simple: a self-assembled transistor with nearly 100 percent purity and very high electron mobility. But it took ten years to get there. University of Groningen Professor of Photophysics and Optoelectronics Maria Antonietta Loi designed polymers which wrap themselves around specific carbon nanotubes in a solution of mixed tubes. Thiol side chains on the polymer bind the tubes to the gold electrodes, creating the resultant transistor.

polymer wrapped nanotube

In our previous work, we learned a lot about how polymers attach to specific carbon nanotubes, Loi explains. These nanotubes can be depicted as a rolled sheet of graphene, the two-dimensional form of carbon. ‘Depending on the way the sheets are rolled up, they have properties ranging from semiconductor to semi-metallic to metallic.’ Only the semiconductor tubes can be used to fabricate transistors, but the production process always results in a mixture.

We had the idea of using polymers with thiol side chains some time ago‘, says Loi. The idea was that as sulphur binds to metals, it will direct polymer-wrapped nanotubes towards gold electrodes. While Loi was working on the problem, IBM even patented the concept. ‘But there was a big problem in the IBM work: the polymers with thiols also attached to metallic nanotubes and included them in the transistors, which ruined them.’

Loi’s solution was to reduce the thiol content of the polymers, with the assistance of polymer chemists from the University of Wuppertal. ‘What we have now shown is that this concept of bottom-up assembly works: by using polymers with a low concentration of thiols, we can selectively bring semiconducting nanotubes from a solution onto a circuit.’ The sulphur-gold bond is strong, so the nanotubes are firmly fixed: enough even to stay there after sonication of the transistor in organic solvents.

Over the last years, we have created a library of polymers that select semiconducting nanotubes and developed a better understanding of how the structure and composition of the polymers influences which carbon nanotubes they select’, says Loi. The result is a cheap and scalable production method for nanotube electronics. So what is the future for this technology? Loi: ‘It is difficult to predict whether the industry will develop this idea, but we are working on improvements, and this will eventually bring the idea closer to the market.’

The results were published in the journal Advanced Materials on 5 April.
Source: http://www.rug.nl/
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Cheap, Non-Toxic, Super Efficient Solar Cell

In the future, solar cells can become twice as efficient by employing a few smart little nano-tricks. Researchers are currently developing the environment-friendly solar cells of the future, which will capture twice as much energy as the cells of today. The trick is to combine two different types of solar cells in order to utilize a much greater portion of the sunlight.

solar_nano

These are going to be the world’s most efficient and environment-friendly solar cells. There are currently solar cells that are certainly just as efficient, but they are both expensive and toxic. Furthermore, the materials in our solar cells are readily available in large quantities on Earth. That is an important point,” says Professor Bengt Svensson of the Department of Physics at the University of Oslo (UiO) and Centre for Materials Science and Nanotechnology (SMN) in Norway.

Using nanotechnology, atoms and molecules can be combined into new materials with very special properties. The goal is to utilize even more of the spectrum of sunlight than is possible at present. Ninety-nine per cent of today’s solar cells are made from silicon, which is one of the most common elements on Earth. Unfortunately, silicon solar cells only utilize 20 per cent of the sunlight. The world record is 25 per cent, but these solar cells are laced with rare materials that are also toxic. The theoretical limit is 30 per cent. The explanation for this limit is that silicon cells primarily capture the light waves from the red spectrum of sunlight. That means that most of the light waves remain unutilized.

The new solar cells will be composed of two energy-capturing layers. The first layer will still be composed of silicon cells. “The red wavelengths of sunlight generate electricity in the silicon cells in a highly efficient manner. We’ve done a great deal of work with silicon, so there is only a little more to gain.” The new trick is to add another layer on top of the silicon cells. This layer is composed of copper oxide and is supposed to capture the light waves from the blue spectrum of sunlight.

Source: http://www.apollon.uio.no/

Nano-Implant Could Restore Sight

A team of engineers at the University of California San Diego (UC San Diego)  and La Jolla-based startup Nanovision Biosciences Inc. have developed the nanotechnology and wireless electronics for a new type of retinal prosthesis that brings research a step closer to restoring the ability of neurons in the retina to respond to light. The researchers demonstrated this response to light in a rat retina interfacing with a prototype of the device in vitro. The technology could help tens of millions of people worldwide suffering from neurodegenerative diseases that affect eyesight, including macular degeneration, retinitis pigmentosa and loss of vision due to diabetes.

Despite tremendous advances in the development of retinal prostheses over the past two decades, the performance of devices currently on the market to help the blind regain functional vision is still severely limited—well under the acuity threshold of 20/200 that defines legal blindness.

cortical neuronsPrimary cortical neurons cultured on the surface of an array of optoelectronic nanowires. Note the extensive neurite outgrowth and network formation

We want to create a new class of devices with drastically improved capabilities to help people with impaired vision,” said Gabriel A. Silva, one of the senior authors of the work and professor in bioengineering and ophthalmology at UC San Diego. Silva also is one of the original founders of Nanovision.

Power is delivered wirelessly, from outside the body to the implant, through an inductive powering telemetry system developed by a team led by Cauwenberghs.

The device is highly energy efficient because it minimizes energy losses in wireless power and data transmission and in the stimulation process, recycling electrostatic energy circulating within the inductive resonant tank, and between capacitance on the electrodes and the resonant tank. Up to 90 percent of the energy transmitted is actually delivered and used for stimulation, which means less RF wireless power emitting radiation in the transmission, and less heating of the surrounding tissue from dissipated power. For proof-of-concept, the researchers inserted the wirelessly powered nanowire array beneath a transgenic rat retina with rhodopsin P23H knock-in retinal degeneration.

The findings are published in a recent issue of the Journal of Neural Engineering.

Source: http://ucsdnews.ucsd.edu/

 

Efficient, Fast, Large-scale 3-D Manufacturing

Washington State University (WSU) researchers have developed a unique, 3-D manufacturing method that for the first time rapidly creates and precisely controls a material’s architecture from the nanoscale to centimeters – with results that closely mimic the intricate architecture of natural materials like wood and bone.

3D manufacturing Hex-Scaffold-web-

This is a groundbreaking advance in the 3-D architecturing of materials at nano- to macroscales with applications in batteries, lightweight ultrastrong materials, catalytic converters, supercapacitors and biological scaffolds,” said Rahul Panat, associate professor in the School of Mechanical and Materials Engineering, who led the research. “This technique can fill a lot of critical gaps for the realization of these technologies.”

The WSU research team used a 3-D printing method to create foglike microdroplets that contain nanoparticles of silver and to deposit them at specific locations. As the liquid in the fog evaporated, the nanoparticles remained, creating delicate structures. The tiny structures, which look similar to Tinkertoy constructions, are porous, have an extremely large surface area and are very strong.

The researchers would like to use such nanoscale and porous metal structures for a number of industrial applications; for instance, the team is developing finely detailed, porous anodes and cathodes for batteries rather than the solid structures that are now used. This advance could transform the industry by significantly increasing battery speed and capacity and allowing the use of new and higher energy materials.

They report on their work in the journal  Science Advances  and have filed for a patent.

Source: https://news.wsu.edu/

Printable solar cells

A University of Toronto (U of T) Engineering innovation could make building printing cells as easy and inexpensive as printing a newspaper. Dr. Hairen Tan and his team have cleared a critical manufacturing hurdle in the development of a relatively new class of solar devices called perovskite solar cells. This alternative solar technology could lead to low-cost, printable solar panels capable of turning nearly any surface into a power generator.

Printable Perovskite SolarCell

Economies of scale have greatly reduced the cost of silicon manufacturing,” says University Professor Ted Sargent (ECE), an expert in emerging solar technologies and the Canada Research Chair in Nanotechnology and senior author on the paper. “Perovskite solar cells can enable us to use techniques already established in the printing industry to produce solar cells at very low cost. Potentially, perovskites and silicon cells can be married to improve efficiency further, but only with advances in low-temperature processes.”

Today, virtually all commercial solar cells are made from thin slices of crystalline silicon which must be processed to a very high purity. It’s an energy-intensive process, requiring temperatures higher than 1,000 degrees Celsius and large amounts of hazardous solvents.

In contrast, perovskite solar cells depend on a layer of tiny crystals — each about 1,000 times smaller than the width of a human hair — made of low-cost, light-sensitive materials. Because the perovskite raw materials can be mixed into a liquid to form a kind of ‘solar ink’, they could be printed onto glass, plastic or other materials using a simple inkjet process.

Source: http://news.engineering.utoronto.ca

War: Never Underestimate The Power Of Small

If there is one lesson to glean from Picatinny Arsenal‘s new course in nanomaterials, it’s this: never underestimate the power of smallNanotechnology is the study of manipulating matter on an atomic, molecular, or supermolecular scale. The end result can be found in our everyday products, such as stained glass, sunscreen, cellphones, and pharmaceutical products. Other examples are in U.S. Army items such as vehicle armor, Soldier uniforms, power sources, and weaponry. All living things also can be considered united forms of nanotechnology produced by the forces of nature.
explosive3-dimensional tomography generated imaging of pores within a nanoRDEX-based explosive

People tend to think that nanotechnology is all about these little robots roaming around, fixing the environment or repairing damage to your body, and for many reasons that’s just unrealistic,” said Rajen Patel, a senior engineer within the Energetics and Warheads Manufacturing Technology Division, or EWMTD. The division is part of the U.S. Army Armament Research, Development and Engineering Center or ARDEC. “For me, nanotechnology means getting materials to have these properties that you wouldn’t expect them to have.”

The subject can be separated into multiple types (nanomedicine, nanomachines, nanoelectronics, nanocomposites, nanophotonics and more), which can benefit areas, such as communications, medicine, environment remediation, and manufacturingNanomaterials are defined as materials that have at least one dimension in the 1-100 nm range (there are 25,400,000 nanometers in one inch.) To provide some size perspective: comparing a nanometer to a meter is like comparing a soccer ball to the earth.

Picatinny‘s nanomaterials class focuses on nanomaterials‘ distinguishing qualities, such as their optical, electronic, thermal and mechanical properties–and teaches how manipulating them in a weapon can benefit the warfighter. While you could learn similar information at a college course, Patel argues that Picatinny‘s nanomaterial class is nothing like a university class. This is because Picatinny‘s nanomaterials class focuses on applied, rather than theoretical nanotechnology, using the arsenal as its main source of examples. “We talk about things like what kind of properties you get, how to make materials, places you might expect to see nanotechnology within the Army,” explained Patel. The class is taught at the Armament University.

In 2010, an article in The Picatinny Voice titled “Tiny particles, big impact: Nanotechnology to help warfighters” discussed Picatinny’s ongoing research on nanopowders. It noted that Picatinny‘s Nanotechnology Lab is the largest facility in North America to produce nanopowders and nanomaterials, which are used to create nanoexplosives. It also mentioned how using nanomaterials helped to develop lightweight composites as an alternative to traditional steel.

Not too long ago making milligram quantities of nanoexplosives was challenging. Now, we have technologies that allow us make pounds of nanoexplosives per hour at low cost“. Pilot scale production of nanoexplosives is currently being performed at ARDEC. The broad interest in developing nanoenergetics such as nano-RDX and nano-HMX is their remarkably low initiation sensitivity. There are two basic approaches to studying nanomaterials: bottom-up (building a large object atom by atom) and top-down (deconstructing a larger material). Both approaches have been successfully employed in the development of nanoenergetics at ARDEC. One of the challenges with manufacturing nonmaterials can be coping with shockwaves. A shockwave initiates an explosive as it travels through a weapon‘s main fill or the booster. When a shockwave travels through an energetic charge, it can hit small regions of defects, or voids, which heat up quickly and build pressure until the explosive reaches detonation. By using nanoenergetics, one could adjust the size and quantity of the defects and voids, so that the pressure isn’t as strong and ultimately prevent accidental detonation.

It’s a major production challenge because if you want to process nanomaterials–if you want to coat it with some polymer for explosives–any kind of medium that can dissolve these types of materials can promote ripening and you can end up with a product which no longer has the nanomaterial that you began with,”  However, nanotechnology research continues to grow at Picatinny as the research advances in the U.S. Army.

Source: https://www.dvidshub.net/

How To Color Textiles Without Polluting Environment

Fast fashion” might be cheap, but its high environmental cost from dyes polluting the water near factories has been well documented. To help stem the tide of dyes from entering streams and rivers, scientists report in the journal ACS Applied Materials & Interfaces a nonpolluting method to color textiles using 3-D colloidal crystals.

peacock feathers

Peacock feathers, opals and butterfly wings have inspired a new way to color voile fabrics without the pollutants of traditional dyes.

Dyes and pigments are chemical colors that produce their visual effect by selectively absorbing and reflecting specific wavelengths of visible light. Structural or physical colors — such as those of opals, peacock feathers and butterfly wings — result from light-modifying micro- and nanostructures. Bingtao Tang and colleagues from Universty of Maryland wanted to find a way to color voile textiles with structural colors without creating a stream of waste.

The researchers developed a simple, two-step process for transferring 3-D colloidal crystals, a structural color material, to voile fabrics. Their “dye” included polystyrene nanoparticles for color, polyacrylate for mechanical stability, carbon black to enhance color saturation and water. Testing showed the method could produce the full spectrum of colors, which remained bright even after washing. In addition, the team said that the technique did not produce contaminants that could pollute nearby water.

Source: http://pubs.acs.org/

Understanding The Risks Of Nanotechnology

When radioactive materials were first introduced into society, it took a while before scientists understood the risks. The same is true of nanotechnology today, according to Dr Vladimir Baulin, from University Rovira i Virgili, in Tarragona, Spain, who together with colleagues has shown for the first time how nanoparticles can cross biological – or lipidmembranes in a paper published in the journal Science Advances
Nanotechnology is all around us, in building materials, in toothpaste and in cleaning products. Across Europe, hundreds of institutions are working together to look at how to monitor exposure, manage the risks and advise on what regulations may be needed under the EU’s NanoSafety Cluster.

nanoparticles effects on lipids

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer (main part of a biological membrane). This process was quantified and the time of each step was estimated. The lipid membrane is the ultimate barrier protecting cells from the outside environment and if the nanoparticles can cross this barrier they may go into cells.’

‘Dr Jean-Baptiste Fleury (from Saarland University in Germany) designed a special set-up with two chambers separated by a lipid bilayer, which contained fluorescent lipids (fat molecules). Non-fluorescent nanoparticles were added to only one of the chambers. In this set-up, nanoparticles became visible only when they touched the fluorescent bilayer and exchanged lipids with it. If one sees the fluorescent nanoparticle in the second chamber, this means it was in contact with the bilayer and it crossed the bilayer from one chamber to another. This was the proof. In addition, the process of translocation was quantified and the time of the crossing was estimated as milliseconds.’

All biological objects, biomolecules, proteins that exist in living organisms evolved over billions of years to adapt to each other. Nanoparticles which are synthesised in the laboratory are thus considered by a living organism as something foreign. It is a big challenge to make them compatible and not toxic.’ ‘I would count the applications of nanoparticles as starting from the 1985 Nobel Prize for the discovery of fullerenes (molecules of hollow football-shaped carbon). This was the start of the nanoparticle boom.’

This is becoming urgent because nanoparticles and nanotechnology in general are entering our lives. Now it is possible to synthesise nanomaterials with precise control, fabricate nanostructures on surfaces and do precise tailoring of the properties of nanoparticles.

‘It is becoming quite urgent to understand the exact mechanisms of nanotoxicity and make a classification depending on the mechanism. Radioactivity or X-rays entered our lives the same way. It took time until researchers understood the mechanisms of action on living organisms and the regulations evolved with our understanding.’

gold nanoparticles cross the membrane

This is the first observation to show directly how tiny gold nanoparticles can cross a lipid bilayer.

An empirical test of toxicity is that you put nanoparticles into the cells and you see the cells are dead, but you don’t understand what has happened, this is empirical. This is a legitimate tool, but it is not enough to address toxicity. Instead, one could start from the properties of nanoparticles and think about classifying nano-objects based on their physical or chemical properties by trying to predict the effect of a given nanoparticle on a cell or tissue beforehand.

I understand, it may look too ambitious, since there are a lot of tiny details that are not considered at the moment in theoretical models or any classification. However, even if it may not be exact, it can give some guidance and it would be possible to make predictions on how nanoparticles and polymers interact with lipid membranes. For example, in this study we used theoretical modelling to suggest the size and surface properties of the nanoparticle that is able to cross the lipid membrane through a certain pathway and it was observed experimentally.’

Source: https://horizon-magazine.eu/

Reconfigurable Materials

Metamaterialsmaterials whose function is determined by structure, not composition — have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat.

In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,” said Katia Bertoldi, John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.”

The research is published in Nature.

Device Doubles The Energy Conversion Of Solar Cells

Scientists from Japan are utilizing nanotechnology advancements to strengthen solar cellsSolar cells convert light into electricity using a bevy of sources, including light from the sun and the burning of natural resources such as oil and natural gas. However, the cells do not convert all light to power equally, which led to scientists attempting to find ways to produce more power. The flame of a gas burner will shift from red to blue as the heat increases because higher temperatures emit light at shorter wavelengths. Higher heat offers more energy, making short wavelengths an important target in the design of solar cells. Kyoto University‘s Takashi Asano, began using optical technologies to improve energy production.

device to double the power of solar cells

Current solar cells are not good at converting visible light to electrical power. The best efficiency is only around 20 percent,” Asano said in a statement. “The problem is that heat dissipates light of all wavelengths, but a solar cell will only work in a narrow range. To solve this, we built a new nano-sized semiconductor that narrows the wavelength bandwidth to concentrate the energy.

The researchers were able to use their nanoscale semiconductor to raise the energy conversion rate to at least 40 percent. Asano and researchers at the Susumu Noda lab had previously attempted to work with higher wavelengths. “Our first device worked at high wavelengths but to narrow output for visible light required a new strategy, which is why we shifted to intrinsic silicon in this current collaboration with Osaka Gas,” Asano said. Visible wavelengths are emitted at 1000 degrees Celsius but conveniently silicon has a melting temperature of over 1,400 degrees Celsius.

This concept was utilized by the scientists, who etched silicon plates to have a large number of identical and equidistantly-spaced rods, the height, radii and spacing of which was optimized for the target bandwidth. Susumu Noda, a professor at Kyoto University, explained the benefits of the advancement: “Our technology has two important benefits. First is energy efficiency: we can convert heat into electricity much more efficiently than before. Secondly is design:  we can now create much smaller and more robust transducers, which will be beneficial in a wide range of applications.”

The study was published in Science Advances.

Source: http://www.rdmag.com/

DNA DataStorage, New Frontier For Nanotechnology

Nanotechnology holds a lot of promise to almost every aspect of our lives from consumer electronics to ending life-threatening illnesses. However, the greatest challenge nanotechnology is facing is the limitation of how much smaller they can shrink the physical size of semiconductors. However, a group of scientists are taking that challenge and if they are successful, we may be well on our way to a future much wilder than science fiction – molecular electronics.

dna

Molecular electronics works at the most minute scale using single molecules including its sub properties and characteristics. The concept of molecular electronics was first originated in 1997 by Mark Reed and his colleagues.

This is what a team of Russian and Israeli scientists are trying to explore as the demand for smaller electronic devices proliferate. Their study proposes to “metallizeDNA using nanoparticles of silver.

First of all, the DNA can hold a great amount of information despite its small size. What’s more intriguing is that the ability of DNA is not limited to storing only genetic information. The study has revealed that the DNA has more uncanny and unique features.

The first feature they discovered was that the DNA has superconducting abilities when placed between two superconductors. The second feature was that they can effect charge transport, which happen when you introduce metal atoms along the strand. Moreover, the scientists also discovered that the conductivity of the DNA molecules depend on the type of substrate they are placed on.

Although the scientists were able to ‘metallize‘ atoms, the distribution was not even along the entire length of the strands, which means not all of it becomes ‘metal.’ However, they found out that these DNA molecules can interact with silver nanoparticles resulting in an even metal DNA strand.

If further experimentation and testing become successful, such nanowire would be 1.1 nanometers high and 400 nanometers long.

The study is published in Advanced Materials.

Source: http://www.universityherald.com/