Articles from September 2015



How To Spray Solar Cells

A new study out of St. Mary’s College of Maryland puts us closer to do-it-yourself spray-on solar cell technology—promising third-generation solar cells utilizing a nanocrystal ink deposition that could make traditional expensive silicon-based solar panels a thing of the past.

In a 2014 study, published in the journal Physical Chemistry Chemical Physics, St. Mary’s College of Maryland energy expert Professor Troy Townsend introduced the first fully solution-processed all-inorganic photovoltaic technology.

spray-on solar cells
While progress on organic thin-film photovoltaics is rapidly growing, inorganic devices still hold the record for highest efficiencies which is in part due to their broad spectral absorption and excellent electronic properties. Considering the recorded higher efficiencies and lower cost per watt compared to organic devices, combined with the enhanced thermal and photo stability of bulk-scale inorganic materials, Townsend, in his 2014 study, focused on an all-inorganic based structure for fabrication of a top to bottom fully solution-based solar cell.

A major disadvantage compared to organics, however, is that inorganic materials are difficult to deposit from solution. To overcome this, Townsend synthesized materials on the nanoscale. Inorganic nanocrystals encased in an organic ligand shell are soluble in organic solvents and can be deposited from solution (i.e., spin-, dip-, spray-coat) whereas traditional inorganic materials require a high temperature vacuum chamber. The solar devices are fabricated from nanoscale particle inks of the light absorbing layers, cadmium telluride/cadmium selenide, and metallic inks above and below. This way, the entire electronic device can be built on non-conductive glass substrates using equipment you can find in your kitchen.

When you spray on these nanocrystals, you have to heat them to make them work,” explained Townsend, “but you can’t just heat the crystals by themselves, you have to add a sintering agent and that, for the last 40 years, has been cadmium chloride, a toxic salt used in commercial thin-film devices. No one has tested non-toxic alternatives for nanoscale ink devices, and we wanted to explore the mechanism of the sintering process to be able to implement safer salts.”

Source: http://www.newswise.com/
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http://pubs.rsc.org/

Blindness Cure From Stem Cells

The first patient has been treated in Britain in a pioneering trial of a new treatment co-developed by Pfizer and derived from embryonic stem cells designed for patients with a condition that can cause blindness. Specialists at London’s Moorfields Eye Hospital said the operation, described as “successful”, was the first of 10 planned for participants in a trial of the treatment for a disease called ‘wetage-related macular degeneration (AMD). The trial will test the safety and efficacy of transplanting eye cells known as retinal pigment epithelium, which have been derived from embryonic stem cells.

eye2Stem cells are the body’s master cells, the source of all other cells. Scientists who support the use of embryonic stem cells say they could transform medicine, providing treatments for blindness, juvenile diabetes or severe injuries. But critics object to them because they are harvested from human embryos.

This trial involves surgeons inserting a specially engineered patch behind the retina to deliver the treatment cells to replace diseased cells at the back of the eye. The first surgery was successfully performed on a patient last month, Moorfields said in a statement on Tuesday, and “there have been no complications to date“.

The patient wishes to remain anonymous, but the team hope to determine her outcome in terms of initial visual recovery by early December,” it added.

Retinal surgeon Lyndon Da Cruz, who is performing the operations, said he hoped many patients “will benefit in the future from transplantation of these cells.”

Macular degeneration accounts for almost 50 percent of all cases of blindness or vision loss in the developed world. It usually affects people over 50 and comes in two forms, wet and dry. Wet AMD, which is less common than dry AMD, is generally caused by abnormal blood vessels that leak fluid or blood into a region in center of the retina.

Source: http://www.reuters.com/

Ocean: NanoMotors Remove Ninety Percent Of The Carbon Dioxide

Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form. The proof of concept study represents a promising route to mitigate the buildup of carbon dioxide, a major greenhouse gas in the environment, said researchers.

nanomotorsNanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate

We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming,” said Virendra V. Singh, a postdoctoral scientist in Wang’s research group and a co-first author of this study. In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

In the future, we could potentially use these micromotors as part of a water treatment system, like a water decarbonation plant,” said Kevin Kaufmann, an undergraduate researcher in Wang’s lab and a co-author of the study.

The team, led by nanoengineering professor Joseph Wang, has published the work this month in the journal Angewandte Chemie.

Source: http://ucsdnews.ucsd.edu/

“Chewing gum” Material 3 Times Stronger Than Steel

Creating futuristic, next generation materials called ‘metallic glass’ that are ultra-strong and ultra-flexible will become easier and cheaper, based on UNSW Australia research that can predict for the first time which combinations of metals will best form these useful materials.

Just like something from science fiction – think of the Liquid-Metal robot assassin in the Terminator films – these materials behave more like glass or plastic than metal.

While still being metals, they become as malleable as chewing gum when heated and can be easily moulded or blown like glass. They are also three times stronger and harder than ordinary metals, on average, and are among the toughest materials known.

 

liquid_terminatorThe Terminator‘s Liquid Metal Man: While still being metals, they become as malleable as chewing gum when heated and can be easily moulded or blown like glass.

They have been described as the most significant development in materials science since the discovery of plastics more than 50 years ago,” says study author, UNSW’s Dr Kevin Laws.

Most metals are crystalline when solid, with their atoms arranged in a highly organised and regular manner. Metallic glass alloys, however, have a highly disordered structure, with the atoms arranged in a non-regular way.

Source: https://newsroom.unsw.edu.au/

How To Trap Greenhouse Gases

Emissions from the combustion of fossil fuels like coal, petroleum and natural gas tend to collect within Earth’s atmosphere as “greenhouse gases” that are blamed for escalating global warming.

So researchers around the globe are on a quest for materials capable of capturing and storing greenhouse gases. This shared goal led researchers at Technische Universität Darmstadt in Germany and the Indian Institute of Technology Kanpur to team up to explore the feasibility of vertically aligned carbon nanotubes (VACNTs) to trap and store two greenhouse gases in particular: carbon dioxide (CO2) and sulfur dioxide (SO2). As the team reports in The Journal of Chemical Physics, from AIP Publishing, they discovered that gas adsorption in VACNTs can be influenced by adjusting the morphological parameters of the carbon nanotube thickness, the distance between nanotubes, and their height.

Carbon nanotubes against greenhouse gases
Snapshots of CO2 adsorption in double-walled carbon nanotube arrays (with an inner tube diameter of 2r=3 nanometers and various inter-tube distance at T=303 K and p=1 bar)

 

These parameters are fundamental for ‘tuning’ the hierarchical pore structure of the VACNTs,” explained Mahshid Rahimi and Deepu Babu, the paper’s lead authors and doctoral students in theoretical physical chemistry and inorganic chemistry at the Technische Universität Darmstadt. “This hierarchy effect is a crucial factor for getting high-adsorption capacities as well as mass transport into the nanostructure. Surprisingly, from theory and by experiment, we found that the distance between nanotubes plays a much larger role in gas adsorption than the tube diameter does.

Source: https://www.aip.org/

Electronic Circuits Mimic The Human Brain

Researchers of the MESA+ Institute for Nanotechnology and the CTIT Institute for ICT Research at the University of Twente in The Netherlands have demonstrated working electronic circuits that have been produced in a radically new way, using methods that resemble Darwinian evolution. The size of these circuits is comparable to the size of their conventional counterparts, but they are much closer to natural networks like the human brain. The findings promise a new generation of powerful, energy-efficient electronics, and have been published in the journal Nature Nanotechnology. The approach of the researchers at the University of Twente is based on methods that resemble those found in Nature. They have used networks of gold nanoparticles for the execution of essential computational tasks. Contrary to conventional electronics, they have moved away from designed circuits. By using ‘designless‘ systems, costly design mistakes are avoided. The computational power of their networks is enabled by applying artificial evolution. This evolution takes less than an hour, rather than millions of years. By applying electrical signals, one and the same network can be configured into 16 different logical gates. The evolutionary approach works around – or can even take advantage of – possible material defects that can be fatal in conventional electronics.
human-head-with-skull-and-artificial-electronic-circuit-bra

One of the greatest successes of the 20th century has been the development of digital computers. During the last decades these computers have become more and more powerful by integrating ever smaller components on silicon chips. However, it is becoming increasingly hard and extremely expensive to continue this miniaturisation. Current transistors consist of only a handful of atoms. It is a major challenge to produce chips in which the millions of transistors have the same characteristics, and thus to make the chips operate properly. Another drawback is that their energy consumption is reaching unacceptable levels. It is obvious that one has to look for alternative directions, and it is interesting to see what we can learn from nature. Natural evolution has led to powerful ‘computers’ like the human brain, which can solve complex problems in an energy-efficient way. Nature exploits complex networks that can execute many tasks in parallel.

Source: http://www.utwente.nl/

Matter: How To See The Structural Arrangements Of Atoms

Atoms are the building blocks of all matter on Earth, and the patterns in which they are arranged dictate how strong, conductive or flexible a material will be. Now, scientists at UCLA have used a powerful microscope to image the three-dimensional positions of individual atoms to a precision of 19 trillionths of a meter, which is several times smaller than a hydrogen atom.

Their observations make it possible, for the first time, to infer the macroscopic properties of materials based on their structural arrangements of atoms, which will guide how scientists and engineers build aircraft components, for example. The research, led by Jianwei (John) Miao, a UCLA professor of physics and astronomy and a member of UCLA’s California NanoSystems Institute, has been published in the online edition of the journal Nature Materials.

 

atoms+image+(2015)The scientists were able to plot the exact coordinates of nine layers of atoms with a precision of 19 trillionths of a meter

For more than 100 years, researchers have inferred how atoms are arranged in three-dimensional space using a technique called X-ray crystallography, which involves measuring how light waves scatter off of a crystal. However, X-ray crystallography only yields information about the average positions of many billions of atoms in the crystal, and not about individual atoms’ precise coordinates.

“It’s like taking an average of people on Earth,” Miao said. “Most people have a head, two eyes, a nose and two ears. But an image of the average person will still look different from you and me.”

Source: http://newsroom.ucla.edu/

Massive Use Of Nanoparticles Found In Popular Foods

Popular lollies, sauces and dressings have been found to contain nanotechnology that the national food regulator has long denied is being widely used in Australia’s food supply.

For many years, Food Standards Australia and New Zealand (FSANZ) has claimed there is “little evidence” of nanotechnology in food because no company had applied for approval. It has therefore not tested for nor regulated the use of nanoparticles. Frustrated at the inertia, environment group Friends of the Earth commissioned tests that found potentially harmful nanoparticles of titanium dioxide and silica in 14 popular products, including Mars’ M&Ms, Woolworths white sauce and Praise salad dressing.

nanoparticles found in foodNanoparticles of silica found in Maggi‘s Roast Meat Gravy

FSANZ kept saying there’s no evidence of it, we’re not going to do any testing. But all 14 samples came back positive, indicating widespread use of nanoparticles in foods in Australia,” said the group’s emerging tech campaigner, Jeremy Tager. “Everybody would want to think food is tested and assured to be safe before it hits supermarket shelves. FSANZ is conducting a living experiment with people. It has inexcusably failed in its role as a regulator.

(A human hair is about 100,000 nanometers wide. Nanoparticles are typically less than 100 nanometres and are used to stretch the shelf life and improve the texture of food).

There is no conclusive evidence that nano-titanium dioxide, which whitens and brightens, and nano-silica, which prevents caking, are completely safe to eat. They have been shown to interfere with the immune system and cause cell damage.

The lab test of the 14 supermarket goods, which also included Eclipse chewy mints, Old El Paso taco mix, and Moccona Cappuccino, was conducted by a world-class nanotechnology research facility at Arizona State University.The Food Standards code does not require nanoparticles to be declared on labelling. Nano-titanium dioxide (E171) can be simply described as the conventional-sized type and as “Colour (171)“. Nano-silica (E551) can be listed as the conventional version and as “Anti-caking agent (551)“. FSANZ told Fairfax Media it had not identified any health impacts linked with the consumption of the two types of nanoparticles.

Source: http://www.smh.com.au/

How To Make Objects Invisible

Scientists at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have devised an ultra-thin invisibilityskincloak that can conform to the shape of an object and conceal it from detection with visible light. Although this cloak is only microscopic in size, the principles behind the technology should enable it to be scaled-up to conceal macroscopic items as well.

Working with brick-like blocks of gold nanoantennas, the Berkeley researchers fashioned a “skin cloak” barely 80 nanometers in thickness, that was wrapped around a three-dimensional object about the size of a few biological cells and arbitrarily shaped with multiple bumps and dents. The surface of the skin cloak was meta-engineered to reroute reflected light waves so that the object was rendered invisible to optical detection when the cloak is activated.

Invisible objectsA 3D illustration of a metasurface skin cloak made from an ultrathin layer of nanoantennas (gold blocks) covering an arbitrarily shaped object. Light reflects off the cloak (red arrows) as if it were reflecting off a flat mirror

This is the first time a 3D object of arbitrary shape has been cloaked from visible light,” said Xiang Zhang, director of Berkeley Lab’s Materials Sciences Division and a world authority on metamaterials – artificial nanostructures engineered with electromagnetic properties not found in nature. “Our ultra-thin cloak now looks like a coat. It is easy to design and implement, and is potentially scalable for hiding macroscopic objects.”

Source: http://newscenter.lbl.gov/

Nano Is eco-friendly

The root of the humble sugar beet is used to make much of the world’s sugar. But the remainder of the plant is destroyed or made into cheap animal feed. But now Scottish scientists are transforming the sugar byproduct into a wonder material named Curran.

vegetable sugarCLICK ON THE IMAGE TO ENJOY THE VIDEO

The feed stock that we use is from a sidestream of the sugar producing industry. It’s the waste pulp that comes after they’re removed the sugar, which is then pressed and dried into pellets for ease of shipment. So you can see the bottom of this stick here I’ve got the dried pellets…..but obviously we want to take this material and turn it into something that has a lot more value“,  says  Dr. David Hepworth, co-founder of the company Cellucomp (UK).

In its factory near Edinburgh, Cellucomp is doing just that. Having originally demonstrated Curran‘s strength by using it to make fishing rods, the firm turned its attention to selling it in granule form, for use in industrial liquids and composites. Its creators say Curran is eco-friendly, twice as strong as carbon fibre, with impressive viscosity. Decorating guru Cait Whitson worked with Cellucomp to create her new range of Whitson paint.,

One of the things I wanted to talk about was durability and one of the things that excited me about the Curran product was that a very small amount of Curran adds a significant amount of durability to the paint product. Secondly was the rheology, about how the paint flowed from the brush“, says Cait Whitson, founder of Whitson Paint. He adds that Curran makes paint scrub-resistant, avoids unsightly brush marks, and helps prevent cracking. With the paint additive business worth a billion dollars, Cellucomp could be sitting on a goldmine. It wants to expand production fivefold within three years.

There are all kinds of potential applications that Curran can be used for. It can go into things like paint and coatings, it can go into concrete, cosmetics. It can even be used for drilling fluids, be an additive to go into your food, and go into composites. So you can imagine one day airplane wings made from Curran“, concludes Christian Kemp-Griffin, CEO of Cellucomp. All of which paints a very bright future for the company..

Source: http://cellucomp.com/

Hybrid Solar Cells 20% More Efficient

Scientists have developed a new hybrid, solar-energy system that harnesses the full spectrum of the sun’s radiation by pairing a photovoltaic cell with polymer films. The films convert the light that goes unused by the solar cell into heat and then converts the heat into electricity. The device produces a voltage more than five times higher than other hybrid systems.

Solar cells today are getting better at converting sunlight to electricity, but commercial panels still harvest only part of the radiation they’re exposed to. Scientists are working to change this using various methods. One approach is to hybridize solar cells with different materials to capture more of the sun’s energy. Professor Eunkyoung Kim, from Seoul’s Yonsei University (Korea), and colleagues turned to a clear, conductive polymer known as PEDOT to try to accomplish this.

hybrid solar cells

A display changes colors, powered solely by a new hybrid solar-energy device

The researchers layered a dye-sensitized solar cell on top of a PEDOT film, which heats up in response to light. Below that, they added a pyroelectric thin film and a thermoelectric device, both of which convert heat into electricity. The efficiency of all components working together was more than 20 percent higher than the solar cell alone. With that boost, the system could operate an LED lamp and an electrochromic display.

A report has been published in the journal ACS Nano.

Source: http://www.acs.org/

Car, Boat, Airplane: Bye Bye Sickness

The misery of motion sickness could be ended within five to ten years thanks to a new treatment being developed by scientists. The cause of motion sickness is still a mystery but a popular theory among scientists says it is to do with confusing messages received by our brains from both our ears and eyes, when we are moving. It is a very common complaint and has the potential to affect all of us, meaning we get a bit queasy on boats or rollercoasters. However, around three in ten people experience hard-to-bear motion sickness symptoms, such as dizziness, severe nausea, cold sweats, and more.

Research from Imperial College London, published today (4 September) in the journal Neurology, shows that a mild electrical current applied to the scalp can dampen responses in an area of the brain that is responsible for processing motion signals. Doing this helps the brain reduce the impact of the confusing inputs it is receiving and so prevents the problem that causes the symptoms of motion sickness. This technique offers a safe and effective intervention that is likely to be available for anyone to buy, in the future.

sicknessCLICK ON THE IMAGE TO ENJOY THE VIDEO

We are confident that within five to ten years people will be able to walk into the chemist and buy an anti-seasickness device. It may be something like a tens machine that is used for back pain”, said Dr Qadeer Arshad from the Department of Medicine at Imperial College London who led the research. “We hope it might even integrate with a mobile phone, which would be able to deliver the small amount of electricity required via the headphone jack. In either case, you would temporarily attach small electrodes to your scalp before travelling – on a cross channel ferry, for example.

Source: http://www3.imperial.ac.uk/