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.


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.


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.


How To Turn Sunlight, Heat and Movement Into Electricity — All at Once

Many forms of energy surround you: sunlight, the heat in your room and even your own movements. All that energy — normally wasted — can potentially help power your portable and wearable gadgets, from biometric sensors to smart watches. Now, researchers from the University of Oulu in Finland have found that a mineral with the perovskite crystal structure has the right properties to extract energy from multiple sources at the same time.

perovskite solar panel

Perovskites are a family of minerals, many of which have shown promise for harvesting one or two types of energy at a time — but not simultaneously. One family member may be good for solar cells, with the right properties for efficiently converting solar energy into electricity. Meanwhile, another is adept at harnessing energy from changes in temperature and pressure, which can arise from motion, making them so-called pyroelectric and piezoelectric materials, respectively.

Sometimes, however, just one type of energy isn’t enough. A given form of energy isn’t always available — maybe it’s cloudy or you’re in a meeting and can’t get up to move around. Other researchers have developed devices that can harness multiple forms of energy, but they require multiple materials, adding bulk to what’s supposed to be a small and portable device.

This week in Applied Physics Letters, Yang Bai and his colleagues at the University of Oulu explain their research on a specific type of perovskite called KBNNO, which may be able to harness many forms of energy. Like all perovskites, KBNNO is a ferroelectric material, filled with tiny electric dipoles analogous to tiny compass needles in a magnet. Within the next year, Bai said, he hopes to build a prototype multi-energy-harvesting device. The fabrication process is straightforward, so commercialization could come in just a few years once researchers identify the best material. “This will push the development of the Internet of Things and smart cities, where power-consuming sensors and devices can be energy sustainable,” he said.

This kind of material would likely supplement the batteries on your devices, improving energy efficiency and reducing how often you need to recharge. One day, Bai said, multi-energy harvesting may mean you won’t have to plug in your gadgets anymore. Batteries for small devices may even become obsolete.


Solar Panels Reach 36.4 Percent Efficiency

Swiss start-up Insolight says its solar panels double the yield achieved by other sun-powered technology. In independent tests the panels reached an efficiency of 36.4 percent.


Traditionally the market sits at around 18 percent and we can double this. Therefore we can double the return on investment for the final client….Our key innovation is that you do not need to rotate the panel in order to follow the sun. We can follow the sun in a flat manner, like any other solar panel, which makes it that our panel can be installed on standard rooftops, with standard mounting technology,” says Florian Gerlich Co-Founder of Insolight company.

Tiny square super cells capture all of the sun’s rays, underneath round lenses, using a patented microtracking system. “Why micro? Why tracking? Micro is a really really small movement that is encapsulated into the solar panel and tracking is to track the sun to concentrate the light into our really tiny solar cell,” comments Noe Bory from Insolight.  An injection-moulded transparent plate moves one centimetre throughout the day, a small sensor detecting the sun’s position.

“As you see here the small squares spread out over the whole surface and under each of these lenses there is a small solar cell. It’s a bit like the lenses that you’re using in your reading lenses or your reading glasses. It’s the same technology, it’s just a particular shape in order to be able to follow the sun from morning to the evening,” adds Florian Gerlich.

The panels may be more expensive to buy than current technology. But Insolight says energy prices will be slashed from 14 US cents per kilowatt hour to 9 cents. A large bed of panels will be tested in Lausanne this summer. Insolight says the system could be market-ready next year.

Breakthrough In The BioMedical Industry

Polyhedral boranes, or clusters of boron atoms bound to hydrogen atoms, are transforming the biomedical industry. These manmade materials have become the basis for the creation of cancer therapies, enhanced drug delivery and new contrast agents needed for radioimaging and diagnosis. Now, a researcher at the University of Missouri has discovered an entirely new class of materials based on boranes that might have widespread potential applications, including improved diagnostic tools for cancer and other diseases as well as low-cost solar energy cells.

Mark Lee Jr., an assistant professor of chemistry in the MU College of Arts and Science, discovered the new class of hybrid nanomolecules by combining boranes with carbon and hydrogen. Boranes are chemically stable and have been tested at extreme heat of up to 900 degrees Celsius or 1,652 degrees Fahrenheit. It is the thermodynamic stability these molecules exhibit that make them non-toxic and attractive to the biomedical, personal computer and alternative energy industries.
Polyhedral boranes

Despite their stability, we discovered that boranes react with aromatic hydrocarbons at mildly elevated temperatures, replacing many of the hydrogen atoms with rings of carbon,” Lee said. “Polyhedral boranes are incredibly inert, and it is their reaction with aromatic hydrocarbons like benzene that will make them more useful.”

Lee also showed that the attached hydrocarbons communicate with the borane core. “The result is that these new materials are highly fluorescent in solution,” Lee said. “Fluorescence can be used in applications such as bio-imaging agents and organic light-emitting diodes like those in phones or television screens. Solar cells and other alternative energy sources also use fluorescence, so there are many practical uses for these new materials.
The findings have been recently published in the international journal Angewandte Chemie.


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.


Paracetamol On Mars

How to produce medicine sustainably and cheaply, anywhere you want, whether in the middle of the jungle or even on Mars? Looking for a ‘mini-factory’ whereby sunlight can be captured to make chemical products? Inspired by the art of nature where leaves are able to collect enough sunlight to produce food, chemical engineers at Eindhoven University of Technology (TU/e) in Netherlands have presented such a scenario. 
Using sunlight to make chemical products has long been a dream of many a chemical engineer. The problem is that the available sunlight generates too little energy to kick off reactions. However, nature is able to do this. Antenna molecules in leaves capture energy from sunlight and collect it in the reaction centers of the leaf where enough solar energy is present for the chemical reactions that give the plant its food (photosynthesis).

Luminescent Solar Concentrator-based Photomicroreactor (LSC-PM, artificial leaf for organic synthesis), research by PhD Dario Cambie & Timothy Noël, group Micro Flow Chemistry and Process Technology, Chemical Engineering and Chemistry, TU Eindhoven. photo: TU/e, Bart van Overbeeke

Luminescent Solar Concentrator-based Photomicroreactor (LSC-PM, artificial leaf for organic synthesis), research by PhD Dario Cambie & Timothy Noël

The researchers came across relatively new materials, known as luminescent solar concentrators (LSC’s), which are able to capture sunlight in a similar way. Special light-sensitive molecules in these materials capture a large amount of the incoming light that they then convert into a specific color that is conducted to the edges via light conductivity. These LSC’s are often used in practice in combination with solar cells to boost the yield.


The results surpassed all their expectations, and not only in the lab. “Even an experiment on a cloudy day demonstrated that the chemical production was 40 percent higher than in a similar experiment without LSC material”, says research leader Noël. “We still see plenty of possibilities for improvement. We now have a powerful tool at our disposal that enables the sustainable, sunlight-based production of valuable chemical products like drugs or crop protection agents.”

For the production of drugs there is certainly a lot of potential. The chemical reactions for producing drugs currently require toxic chemicals and a lot of energy in the form of fossil fuels. By using visible light the same reactions become sustainable, cheap and, in theory, countless times faster. But Noël believes it should not have to stop there. “Using a reactor like this means you can make drugs anywhere, in principle, whether malaria drugs in the jungle or paracetamol on Mars. All you need is sunlight and this mini-factory.

The findings are described in the journal Angewandte Chemie.


Nanowire Inks For Printable Electronics

By suspending tiny metal nanoparticles in liquids, Duke University scientists are brewing up conductive ink-jet printer “inks” to print inexpensive, customizable circuit patterns on just about any surfacePrinted electronics, which are already being used on a wide scale in devices such as the anti-theft radio frequency identification (RFID) tags you might find on the back of new DVDs, currently have one major drawback: for the circuits to work, they first have to be heated to melt all the nanoparticles together into a single conductive wire, making it impossible to print circuits on inexpensive plastics or paper. A new study by Duke researchers shows that tweaking the shape of the nanoparticles in the ink might just eliminate the need for heat.

By comparing the conductivity of films made from different shapes of silver nanostructures, the researchers found that electrons zip through films made of silver nanowires much easier than films made from other shapes, like nanospheres or microflakes. In fact, electrons flowed so easily through the nanowire films that they could function in printed circuits without the need to melt them all together.


The nanowires had a 4,000 times higher conductivity than the more commonly used silver nanoparticles that you would find in printed antennas for RFID tags,” said Benjamin Wiley, assistant professor of chemistry at Duke. “So if you use nanowires, then you don’t have to heat the printed circuits up to such high temperature and you can use cheaper plastics or paper.”

There is really nothing else I can think of besides these silver nanowires that you can just print and it’s simply conductive, without any post-processing,” Wiley added.

These types of printed electronics could have applications far beyond solar cells; researchers envision using the technology to make solar cells, printed displays, LEDS, touchscreens, amplifiers, batteries and even some implantable bio-electronic devices. The results appeared online Dec. 16 in ACS Applied Materials and Interfaces.


NanoRobots With Grippers Travel Through the Bloodstream To Capture Cancer Cells

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used in a variety of applications, including microscopic actuators and grippers for surgical robots, light-powered micro-mirrors for optical telecommunications systems, and more efficient solar cells and photodetectors.

nanorobotsThis is a new area of science,” said Balaji Panchapakesan, associate professor of mechanical engineering at WPI and lead author of a paper about the new material published in Scientific Reports, an open access journal from the publishers of Nature. “Very few materials are able to convert photons directly into mechanical motion. In this paper, we present the first semiconductor nanocomposite material known to do so. It is a fascinating material that is also distinguished by its high strength and its enhanced optical absorption when placed under mechanical stress.”

Tiny grippers and actuators made with this material could be used on Mars rovers to capture fine dust particles.” Panchapakesan noted. “They could travel through the bloodstream on tiny robots to capture cancer cells or take minute tissue samples. The material could be used to make micro-actuators for rotating mirrors in optical telecommunications systems; they would operate strictly with light, and would require no other power source.”

Like other semiconductor materials, molybdenum disulfide, the material described in the Scientific Report paper, is characterized by the way electrons are arranged and move about within its atoms.


Perovskite Solar Cells One Step Closer To Mass Production

With the high environmental cost of conventional energy sources and the finite supply of fossil fuels, the importance of renewable energy sources has become much more apparent in recent years. However, efficiently harnessing solar energy for human use has been a difficult task. While silicon-based solar cells can be used to capture sunlight energy, they are costly to produce on an industrial scale. Research from the Energy Materials and Surface Sciences Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan, led by Prof. Yabing Qi, has focused on using organo-metal halide perovskite films in solar cells. These perovskite films are highly crystalline materials that can be formed by a large number of different chemical combinations and can be deposited at low cost. Recent publications from Prof. Qi’s lab cover three different areas of innovation in perovskite film research: a novel post annealing treatment to increase perovskite efficiency and stability, a discovery of the decomposition products of a specific perovskite, and a new means of producing perovskites that maintains solar efficiency when scaled up.

perovskite solar panel

In order to be useful as solar cells, perovskite films must be able to harvest solar energy at a high efficiency that is cost-effective, be relatively easy to manufacture, and be able to withstand the outdoor environment over a long period of time. Dr. Yan Jiang in Prof. Qi’s lab has recently published research in Materials Horizons that may help increase the solar efficiency of the organo-metal halide perovskite MAPbI3. He discovered that the use of a methylamine solution during post-annealing led to a decrease in problems associated with grain boundaries. Grain boundaries manifest as gaps between crystalline domains and can lead to unwanted charge recombination. This is a common occurrence in perovskite films and can reduce their efficiency, making the improvement of grain boundary issues essential to maintain high device performance. Dr. Jiang’s novel post annealing treatment produced solar cells that had fused grain boundaries, reduced charge recombination, and displayed an outstanding conversion efficiency of 18.4%. His treated perovskite films also exhibited exceptional stability and reproducibility, making his method useful for industrial production of solar cells.


Nanocomputer Confirms The Moore’s Law

A research team led by faculty scientist Ali Javey at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has done just that by creating a transistor with a working 1-nanometer gate. For comparison, a strand of human hair is about 50,000 nanometers thick. The development could be key to keeping alive Intel co-founder Gordon Moore’s prediction that the density of transistors on integrated circuits would double every two years, enabling the increased performance of our laptops, mobile phones, televisions, and other electronics. For more than a decade, engineers have been eyeing the finish line in the race to shrink the size of components in integrated circuits. They knew that the laws of physics had set a 5-nanometer threshold on the size of transistor gates among conventional semiconductors, about one-quarter the size of high-end 20-nanometer-gate transistors now on the market.


We made the smallest transistor reported to date,” said Javey, lead principal investigator of the Electronic Materials program in Berkeley Lab’s Materials Science Division. “The gate length is considered a defining dimension of the transistor. We demonstrated a 1-nanometer-gate transistor, showing that with the choice of proper materials, there is a lot more room to shrink our electronics.” The key was to use carbon nanotubes and molybdenum disulfide (MoS2), an engine lubricant commonly sold in auto parts shops. MoS2 is part of a family of materials with immense potential for applications in LEDs, lasers, nanoscale transistors, solar cells, and more.

The findings were published in the journal Science.


Tiny High-Performance Solar Cells

University of Wisconsin—Madison engineers have created high-performance, micro-scale solar cells that outshine comparable devices in key performance measures. The miniature solar panels could power myriad personal deviceswearable medical sensors, smartwatches, even autofocusing contact lenses. Large, rooftop photovoltaic arrays generate electricity from charges moving vertically. The new, small cells, described today (Aug. 3, 2016) in the journal Advanced Materials Technologies, capture current from charges moving side-to-side, or laterally. And they generate significantly more energy than other sideways solar systems.

New-generation lateral solar cells promise to be the next big thing for compact devices because arranging electrodes horizontally allows engineers to sidestep a traditional solar cell fabrication process: the arduous task of perfectly aligning multiple layers of the cell’s material atop one another.

solar cells

From a fabrication point of view, it is always going to be easier to make side-by-side structures,” says Hongrui Jiang, a UW–Madison professor of electrical and computer engineering and corresponding author on the paper. “Top-down structures need to be made in multiple steps and then aligned, which is very challenging at small scales.

Lateral solar cells also offer engineers greater flexibility in materials selection.

Top-down photovoltaic cells are made up of two electrodes surrounding a semiconducting material like slices of bread around the meat in a sandwich. When light hits the top slice, charge travels through the filling to the bottom layer and creates electric current.

In the top-down arrangement, one layer needs to do two jobs: It must let in light and transmit charge. Therefore, the material for one electrode in a typical solar cell must be not only highly transparent, but also electrically conductive. And very few substances perform both tasks well.