Posts belonging to Category coatings

Green Solar Panels And Other Colors

Researchers from AMOLF, the University of Amsterdam (UvA) and the Energy Research Centre of the Netherlands (ECN) have developed a technology to create efficient bright green colored solar panels. Arrays of silicon nanoparticles integrated in the front module glass of a silicon heterojunction solar cell scatter a narrow band of the solar spectrum and create a green appearance for a wide range of angles. The remainder of the solar spectrum is efficiently coupled into the solar cell. The current generated by the solar panel is only  reduced by 10%. The realization of efficient colorful solar panels is an important step for the integration of solar panels into the built environment and landscape.
research has much focused on maximizing the electricity yield obtained from solar panels: nowadays, commercial panels have a maximum conversion efficiency from sunlight into electricity of around 22%. To reach such high efficiency, silicon solar cells have been equipped with a textured surface with an antireflection layer to absorb as much light as possible. This creates a dark blue or black appearance of the solar panels.

To create the colored solar panels the researchers have used the effect of Mie scattering, the resonant backscattering of light with a particular color by nanoparticles. They integrated dense arrays of silicon nanocylinders with a diameter of 100 nm in the top module cover slide of a high-efficiency silicon heterojunction solar cell. Due to the resonant nature of the light scattering effect, only the green part of the spectrum is reflected; the other colors are fully coupled into the solar cell. The current generated by the mini solar panel (0,7 x 0,7 cm2)  is only reduced by 10%. The solar panel appears green over a broad range of angles up to 75 degrees. The nanoparticles are fabricated using soft-imprint lithography, a technique that can readily be scaled up to large-area fabrication.
The light scattering effect due to Mie resonances is easily controllable: by changing the size of the nanoparticles the wavelength of the resonant light scattering can be tuned. Following this principle the researchers are now working to realize solar cells in other colors, and on a combination of different colors to create solar panels with a white appearance. For the large-scale application of solar panels, it is essential that their color can be tailored.

The new design was published online in the journal Applied Physics Letters.


Biodegradable Car

TU/Ecomotive (Netherlands) says ‘Lina‘ is the world’s first car with a fully biocomposite body structure. The 4-seat e-car‘s chassis uses a combination of bio-composite and bio-plastic made from sugarbeet.


It’s made of flax, the outside is made of flax fibres, together with polypropylene. It’s pressed and heated to make flat panels. In the middle you can see polylactic acid, the honeycomb structure of that material, which adds to the strength and weight savings of the sandwich panel. All structural parts of the car are made of this material,” says Yanic Van Riel, TU/Ecomotive.

The biocomposite has a similar strength-weight ratio to fibreglass, making the car light, greatly reducing battery size.

The car weighs only 310 kilograms which is really light for a car. That’s why we only need 30 kilograms of batteries. And on those 30 kilograms of battery packs we can drive around 100 kilometres, which is about four times more efficient than a BMW i3 right now and that’s in real city driving, so braking, stopping, accelerating, not just like the most optimal driving,” explains Yanic Van Riel.

Lina has a top speed of around 50 miles per hour. Electronic features include NFCnearfield communication technology.  “We can open our doors with NFC technology and a car will immediately recognise who is driving it. So if I’m opening it, it will save all the data from me and if someone else opens it, it will save his data. In that way we can use this car for carsharing apps, which other companies are creating. Also we have a hood system which projects the speed and all the information of the car into the front window, so we can see it through the window and still see the road, so it’s more safe,” adds Noud Van De Gevel, TU/Ecomotive.

The team hopes the prototype will soon be declared roadworthy, allowing it to be tested on Eindhoven city streets.


Cheap, Robust Catalyst Splits Water Into Hydrogen And Oxygen

Splitting water into hydrogen and oxygen to produce clean energy can be simplified with a single catalyst developed by scientists at Rice University and the University of Houston. The electrolytic film produced at Rice and tested at Houston is a three-layer structure of nickel, graphene and a compound of iron, manganese and phosphorus. The foamy nickel gives the film a large surface, the conductive graphene protects the nickel from degrading and the metal phosphide carries out the reactionRice chemist Kenton Whitmire and Houston electrical and computer engineer Jiming Bao and their labs developed the film to overcome barriers that usually make a catalyst good for producing either oxygen or hydrogen, but not both simultaneously.

A catalyst developed by Rice University and the University of Houston splits water into hydrogen and oxygen without the need for expensive metals like platinum. This electron microscope image shows nickel foam coated with graphene and then the catalytic surface of iron, manganese and phosphorus

Regular metals sometimes oxidize during catalysis,” Whitmire said. “Normally, a hydrogen evolution reaction is done in acid and an oxygen evolution reaction is done in base. We have one material that is stable whether it’s in an acidic or basic solution.

The discovery builds upon the researchers’ creation of a simple oxygen-evolution catalyst revealed earlier this year. In that work, the team grew a catalyst directly on a semiconducting nanorod array that turned sunlight into energy for solar water splittingElectrocatalysis requires two catalysts, a cathode and an anode. When placed in water and charged, hydrogen will form at one electrode and oxygen at the other, and these gases are captured. But the process generally requires costly metals to operate as efficiently as the Rice team’s catalyst.

The standard for hydrogen evolution is platinum,” Whitmire explained. “We’re using Earth-abundant materials — iron, manganese and phosphorus — as opposed to noble metals that are much more expensive.

The robust material is the subject of a paper in Nano Energy.


Move And Produce Electricity To Power Your Phone

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting down. A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.


In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment,” said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.
This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint’s advances in materials and energy harvesting,” observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device’s development.

Doctoral students Nitin Muralidharan and Mengya Lic o-led the effort to make and test the devices. When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz, said Muralidharan.

The new energy harvesting system is described in a paper titled “Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets” published  by the journal ACS Energy Letters.


SuperPowerful Tiny Device Converts Light Into Electricity

In today’s increasingly powerful electronics, tiny materials are a must as manufacturers seek to increase performance without adding bulk. Smaller also is better for optoelectronic devices — like camera sensors or solar cells —which collect light and convert it to electrical energy. Think, for example, about reducing the size and weight of a series of solar panels, producing a higher-quality photo in low lighting conditions, or even transmitting data more quickly.

However, two major challenges have stood in the way: First, shrinking the size of conventionally used “amorphousthin-film materials also reduces their quality. And second, when ultrathin materials become too thin, they are almost transparent — and actually lose some ability to gather or absorb light.

Now, in a nanoscale photodetector that combines both a unique fabrication method and light-trapping structures, a team of engineers from the University at Buffalo (UB) and the University of Wisconsin-Madison (UW-Madison) has overcome both of those obstacles. The researchers — electrical engineers Qiaoqiang Gan at UB, and Zhenqiang (Jack) Ma and Zongfu Yu at UW-Madison — described their device, a single-crystalline germanium nanomembrane photodetector on a nanocavity substrate, in the July 7, 2017, issue of the journal Science Advances.

This image shows the different layers of the nanoscale photodetector, including germanium (red) in between layers of gold or aluminum (yellow) and aluminum oxide (purple). The bottom layer is a silver substrate

We’ve created an exceptionally small and extraordinarily powerful device that converts light into energy,” says Gan, associate professor of electrical engineering in UB’s School of Engineering and Applied Sciences, and one of the paper’s lead authors. “The potential applications are exciting because it could be used to produce everything from more efficient solar panels to more powerful optical fibers.”

The idea, basically, is you want to use a very thin material to realize the same function of devices in which you need to use a very thick material,” says Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, also a lead author. Nanocavities are made up of an orderly series of tiny, interconnected molecules that essentially reflect, or circulate, light.

The new device is an advancement of Gan’s work developing nanocavities that increase the amount of light that thin semiconducting materials like germanium can absorb. It consists of nanocavities sandwiched between a top layer of ultrathin single-crystal germanium and a bottom, reflecting layer of silver.


Hydrogen-based Electric Bus

FAST, a student team from Eindhoven University of Technology (TU/e) in Netherlands, has designed the world’s first system that allows a bus to drive on formic acid. Their self-built system comprises an electric bus that is hooked up to a small trailer – which the students have christened ‘REX’ – in which formic acid is converted into electricity. The benefits of using formic acid are that it is sustainable, CO2-neutral, safe and liquid.


Hydrozine is the energy carrier’s official name. It’s 99% formic acid with a performance enhancing agent. What is striking is that Team FAST, consisting of 35 students, developed this so far unknown fuel all by itself. At the beginning of 2016 they presented an initial scale model that illustrated how it works. After another twenty months of hard work, they now have a system that is 42,000 times stronger and is capable of 25kW power.

In the trailer that was built by the team hydrozine is split into hydrogen and CO2. The hydrogen is then used to produce electricity that powers a city bus of the Eindhoven company VDL. The team calls the trailer a ‘range extender’, REX for short, because the trailer expands the existing range of the bus as a standalone component. The team is still running final tests with the aim of the bus actually operating by the end of this year.

The benefits of hydrozine are many. It is a cheap and safe alternative to the transport of hydrogen that normally requires large tanks and high pressure. The CO2 produced in splitting the hydrozine is also used in the production process, which results in zero net CO2. Hydrozine has four times as much energy density as a battery and since it is a liquid, very few modifications will be required to the current infrastructure of filling stations.


How To Power The U.S. With Solar

Speaking recently at the National Governors Association Summer Meeting in Rhode Island, Elon Musk told his audience — including 30 United States governors — that it’s possible to power the nation with solar energy.

If you wanted to power the entire U.S. with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States,” Musk said. “The batteries you need to store the energy, to make sure you have 24/7 power, is 1 mile by 1 mile. One square-mile. That’s it.”

Why solar? Well, as Musk explained, as far as energy sources go, we can count on solar to come through for us: “People talk about fusion and all that, but the sun is a giant fusion reactor in the sky. It’s really reliable. It comes up every day. If it doesn’t we’ve got bigger problems.”

At present, about 10 percent of the U.S. is powered by renewable energy sources. To achieve a complete renewable energy power, Musk thinks solar is the way to go.

To start, he suggested combining rooftop solar and utility-scale solar plants. The former would be on the rooftops of houses in the suburbs, while the latter could power other areas. As we’ve seen with Tesla’s new rooftop solar unit, and efforts in other countries, like Australia, to build large-scale solar plants, this is a goal well within reach.

Next, while in transition from fossil fuel to solar, it’d be necessary to rely on other renewables. “We’ll need to be a combination of utility-scale solar and rooftop solar, combined with wind, geothermal, hydro, probably some nuclear for a while, in order to transition to a sustainable situation,” Musk explained.

Finally, the U.S. has to build more localized power sources, like the rooftop solar setups. “People do not like transmission lines going through their neighborhood, they really don’t like that, and I agree,” Musk said. “Rooftop solar, utility solar; that’s really going to be a solution from the physics standpoint. I can really see another way to really do it.”

When this happens, the U.S. would eliminate about 1,821 million metric tons of carbon dioxide (CO2) emissions generated by the country’s current electric power sector — 35 percent of the overall CO2 energy-related emissions in the U.S.


Solar Nanotechnology-based Desalination

A new desalination system has been developed that combines membrane distillation technology and light-harvesting nanophotonics. Called nanophotonics-enabled solar membrane distillation technology, or NESMD for short, the development has come from the Center for Nanotechnology Enabled Water Treatment (NEWT), based at Rice University. The system works whereby hot salt water is flowed across one side of a porous membrane and cold freshwater is flowed across the otherWater vapor is naturally drawn through the membrane from the hot to the cold side, and because the seawater doesn’t need to be boiled, the energy requirements are less than they would be for traditional distillation, according to the researchers. However, the energy costs are still significant because heat is continuously lost from the hot side of the membrane to the cold.

Unlike traditional membrane distillation, NESMD benefits from increasing efficiency with scale,” said Rice’s Naomi Halas, a corresponding author on the paper and the leader of NEWT‘s  nanophotonics research efforts. “It requires minimal pumping energy for optimal distillate conversion, and there are a number of ways we can further optimise the technology to make it more productive and efficient.

The distillation membrane in the chamber contained a specially designed top layer of carbon black nanoparticles infused into a porous polymer. The light-capturing nanoparticles heated the entire surface of the membrane when exposed to sunlight. A thin half-millimeter-thick layer of salt water flowed atop the carbon-black layer, and a cool freshwater stream flowed below.

Rice scientist and water treatment expert Qilin Li said the water production rate increased greatly by concentrating the sunlight: “The intensity got up 17.5 kilowatts per meter squared when a lens was used to concentrate sunlight by 25 times, and the water production increased to about 6 liters per meter squared per hour.”

In the PNAS study, researchers offered proof-of-concept results based on tests with an NESMD chamber about the size of three postage stamps and just a few millimeters thick.


Sion, The Solar-Powered Car

What has room for 6 passengers, an all-electric range of up to 155 miles (250 kilometers), and a body covered in solar panels that can add as many as 18 miles (30 kilometers) of driving a day from sunlight? That would be the Sono Motors Sion, an innovative solar-powered car from a team of German entrepreneurs that is scheduled to have its world debut on July 27 (2017).

The Sion project was able to move forward thanks to an Indiegogo crowdfunding campaign last year that raised over a half million dollars. More than 1,000 people have participated so far.

The car will have two versions. The Urban comes with a 14.4 kilowatt-hour battery pack. It has a range of about 75 miles (121 kilometers) and will cost $13,200. The Extender version has a 30 kilowatt-hour battery and a range of 155 miles (250 kilometers). Its target price is $17,600. Neither price includes the battery. Like the Renault Zoe, customers will either buy the battery separately or lease it. The leasing option gives owners the flexibility to upgrade the battery later as improvements in battery technology become available.

The hood, roof, and rear hatch of the Sion are covered with monocrystalline silicon cells that are 21% efficient. On a sunny day, they can generate enough electricity to add 18 miles of range. The solar cells are 8 millimeters thick and embedded in a polycarbonate layer that is shatterproof, weather resistant, and light in weight. The Sion can also be 80% charged using an AC outlet in about 30 minutes, according to company claims. No DC charging option is available. The car also comes with an outlet that can power electronic devices.

Inside, all the seats of the 5 door hatchback fold flat, offering multiple configurations for carrying passengers and cargo. There is a 10 inch center display and smartphone connectivity via WiFi or Bluetooth. The ventilation system is called breSono and incorporates a dollop of moss, which is said to act as a natural filter when an electrical charge is applied.

The company will offer an online maintenance and repair system it calls reSono. It allows owners to order parts online and comes with a video that shows them how to install the parts when they arrive.  Or they can take the car and the parts to any local auto repair shop facility to get them installed.


Nanotechnology Spacecraft

Renowned physicist Stephen Hawking is proposing a nanotechnology spacecraft that can travel at a fifth of the speed of light. At that speed, it could reach the nearest star in 20 years and send back images of a suspected “Second Earth” within 5 years. That means if we launched it today, we would have our first look at an Earth-like planet within 25 years.

Hawking proposed a nano-spacecraft, termed “Star Chip,” at the Starmus Festival IV: Life And The Universe, Trondheim, Norway, June 18 – 23, 2017. Hawking told attendees that every time intelligent life evolves it annihilates itself with “war, disease and weapons of mass destruction.” He asserted this as the primary reason why advanced civilizations from another part of the Universe are not contacting Earth and the primary reason we need to leave the Earth. His advocates we colonize a “Second Earth.”

Scientific evidence appears to support Hawking’s claim. The SETI Institute has been listening for evidence of extraterrestrial radio signals, a sign of advanced extraterrestrial life, since 1984. To date, their efforts have been futile. SETI claims, rightly, that the universe is vast, and they are listening to only small sectors, which is much like finding a needle in a haystack.


Nano-based Material Is 60 Times More Efficient To Produce Hydrogen

Global climate change and the energy crisis mean that alternatives to fossil fuels are urgently needed. Among the cleanest low-carbon fuels is hydrogen, which can react with oxygen to release energy, emitting nothing more harmful than water (H2O) as the product. However, most hydrogen on earth is already locked into H2O (or other molecules), and cannot be used for power.

Hydrogen can be generated by splitting H2O, but this uses more energy than the produced hydrogen can give back. Water splitting is often driven by solar power, so-called “solar-to-hydrogenconversion. Materials like titanium oxide, known as semiconductors with the wide band-gap, are traditionally used to convert sunlight to chemical energy for the photocatalytic reaction. However, these materials are inefficient because only the ultraviolet (UV) part of light is absorbed—the rest spectrum of sunlight is wasted.

Now, a team in Osaka University has developed a material to harvest a broader spectrum of sunlight. The three-part composites of this material maximize both absorbing light and its efficiency for water splitting. The core is a traditional semiconductor, lanthanum titanium oxide (LTO). The LTO surface is partly coated with tiny specks of gold, known as nanoparticles. Finally, the gold-covered LTO is mixed with ultrathin sheets of the element black phosphorus (BP), which acts as a light absorber.

BP is a wonderful material for solar applications, because we can tune the frequency of light just by varying its thickness, from ultrathin to bulk,” the team leader Tetsuro Majima says. “This allows our new material to absorb visible and even near infrared light, which we could never achieve with LTO alone.”

By absorbing this broad sweep of energy, BP is stimulated to release electrons, which are then conducted to the gold nanoparticles coating the LTO. Gold nanoparticles also absorb visible light, causing some of its own electrons to be jolted out. The free electrons in both BP and gold nanoparticles are then transferred into the LTO semiconductor, where they act as an electric current for water splitting.

Hydrogen production using this material is enhanced not only by the broader spectrum of light absorption, but by the more efficient electron conduction, caused by the unique interface between two dimensional materials of BP and LTO. As a result, the material is 60 times more active than pure LTO.


Bubbles And The Future Of Electric Cars

With about three times the energy capacity by weight of today’s lithium-ion batteries, lithium-air batteries could one day enable electric cars to drive farther on a single charge. But the technology has several holdups, including losing energy as it stores and releases its charge. If researchers could better understand the basic reactions that occur as the battery charges and discharges electricity, the battery’s performance could be improved. One reaction that hasn’t been fully explained is how oxygen blows bubbles inside a lithium-air battery when it discharges. The bubbles expand the battery and create wear and tear that can cause it to fail.

A paper in Nature Nanotechnology provides the first step-by-step explanation of how lithium-air batteries form bubbles. The research was aided by a first-of-a-kind video that shows bubbles inflating and later deflating inside a nanobattery. Researchers had previously only seen the bubbles, but not how they were created.

If we fully understand the bubble formation process, we could build better lithium-air batteries that create fewer bubbles,” noted the paper’s corresponding author, Chongmin Wang, of the Department of Energy’s Pacific Northwest National Laboratory (PNNL). “The result could be more compact and stable batteries that hold onto their charge longer.”

Wang works out of EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility located at PNNL. His co-authors include other PNNL staff and a researcher from Tianjin Polytechnic University in China.

The team’s unique video may be a silent black-and-white film, but it provides plenty of action. Popping out from the battery’s flat surface is a grey bubble that grows bigger and bigger. Later, the bubble deflates, the top turning inside of itself until only a scrunched-up shell is left behind.

The popcorn-worthy flick was captured with an in-situ environmental transmission electron microscope at EMSL. Wang and his colleagues built their tiny battery inside the microscope’s column. This enabled them to watch as the battery charged and discharged inside.

Video evidence led the team to propose that as the battery discharges, a sphere of lithium superoxide jets out from the battery’s positive electrode and becomes coated with lithium oxide. The sphere’s superoxide interior then goes through a chemical reaction that forms lithium peroxide and oxygen. Oxygen gas is released and inflates the bubble. When the battery charges, lithium peroxide decomposes, and leaves the former bubble to look like a deflated balloon.