Nanotechnology: A Treasure Trove With 1000 New 2D Materials

2D materials, which consist of a few layers of atoms, may well be the future of nanotechnology. They offer potential new applications and could be used in small, higher-performance and more energy-efficient devices. 2D materials were first discovered almost 15 years ago, but only a few dozen of them have been synthesized so far. Now, thanks to an approach developed by researchers from EPFL‘s Theory and Simulation of Materials Laboratory (THEOS) and from NCCR-MARVEL for Computational Design and Discovey of Novel Materials, many more promising 2D materials may now be identified. Their work was recently published in the journal Nature Nanotechnology, and even got a mention on the cover page.

The first 2D material to be isolated was graphene, in 2004, earning the researchers who discovered it a Nobel Prize in 2010. This marked the start of a whole new era in electronics, as graphene is light, transparent and resilient and, above all, a good conductor of electricity. It paved the way to new applications in numerous fields such as photovoltaics and optoelectronics.

A team from EPFL (Ecole Polytechnique Fédérale de Lausanne) and NCCR Marvel in Switzerland has identified more than 1,000 materials with a particularly interesting 2D structure. Their research, which made the cover page of Nature Nanotechnology, paves the way for groundbreaking technological applications.

To find other materials with similar properties, we focused on the feasibility of exfoliation,” explains Nicolas Mounet, a researcher in the THEOS lab and lead author of the study. “But instead of placing adhesive strips on graphite to see if the layers peeled off, like the Nobel Prize winners did, we used a digital method.”


The Biggest Solar Plant Ever Built produces electricity at $0.10/kWh

The massive, 648-megawatt array was officially linked to the grid after being hooked up to a 400kV substation, the operator Adani Green Energy Ltd announced. The plant is spread across 2,500 acres in the town of Kamuthi in the Ramanathapuram district (India)  and will supply enough clean, green energy for 300,000 homes. The Deccan Chronicle reported that the $679 million solar park consists of 380,000 foundations, 2.5 million solar modules, 576 inverters, 154 transformers and 6,000-kilometers of cables. The plant was built with parts and machinery from around the world. Adani Group chairman Gautam Adani formally dedicated the structure to the nation.


“This is a momentous occasion for the state of Tamil Nadu as well as the entire country“, he said. “We are extremely happy to dedicate this plant to the nation; a plant of this magnitude reinstates the country’s ambitions of becoming one of the leading green energy producers in the world.”

India has an ambitious solar energy goal. In 2014, Indian Prime Minister Narendra Modi announced plans to increase solar power capacity to 100 gigawatts by 2022, five times higher than the previous target.

The plant was commissioned by Tamil Nadu chief minister J Jayalalithaa. Indian Express reported in July 2015 that the state government would buy the entire 648 megawatts produced by Adani at a fixed price of $0.10/kWh (Rs 7.01/kWh) for 25 years.


Solar Hubs Provide Clean Water, Electricity & Internet to 3000 people

The Italian company Watly aims to deliver a hat trick of very needful things to the developing world, in the form of both a standalone unit and as a network of units. The team of this ambitious company describes their creation as the “biggest solar-powered computer in the world,” which combines solar photovoltaics (PV) and battery storage for powering the unit (and for charging external devices), with a water filtration system and an internet connectivity and telecommunications hub. The Watly system, which has been in the works for the last few years, and has now attracted the attention of The Discovery Channel, was run as a pilot program at a village in Ghana, where the 2.0 version of the device was successfully deployed to deliver clean drinking water to residents.

watly solar hub

The next step, however, is to build out the Watly 3.0 system, which is the full-sized version of the device, measuring some 40 meters long, and which is expected to be able to provide as much as 5000 liters of water per day, every day, for at least 15 years, along with producing solar electricity and charging services to as many as 3000 people. According to the company, one unit could offset the emissions equivalent of 2500 barrels of oil over the course of those 15 years, along with providing clean water and an off-grid power source. To get to that next step, Watly has turned to – wait for it – crowdfunding with an Indiegogo campaign that seeks to raise money for the installation of the 3.0 version as a pilot program in Africa (location TBD).

Along with the solar power and drinking water, Watly aims to provide an internet/telecom hub for local residents, with an onboard system for connecting to 3G/4G, radio link data systems, and/or satellites, as well as to communicate with other Watly units to act as a node in an “EnergyNet.”

Watly is a powerful communication device that can collect and send any kind of data (videos, images, audios, texts, ratios, etc.) to the Internet as well as to any other compatible communication device. A single Watly is a standing alone machine, but two or more Watlys become a network where each node is auto-powered, self-sustained and multi-functional.


Dye Solar Cells Make Your Mouse Battery Obsolete

These little glass squares could just be the answer to charging all your electronics. The glass-printed photovoltaic cells are a form of Dye Solar Cell technology created by Israeli company 3G Solar Photovoltaics. They’re so sensitive they can generate power from indirect, indoor lighting. Check it out. The company’s head of R&D Nir Stein is taking the batteries out of this mouse, which has the company’s dye solar cell module installed on top.

solar cells powered mouseCLICK ON THE IMAGE TO ENJOY THE VIDEO

What you see here is a computer mouse that has a bluetooth connectivity inside it and is powered by 3G solar photovoltaic cells. So when you have thousands of sensors, for instance in a building, which is going to happen in the next few years, you’ll never have to change a battery again,” says Nir Stein.
Dye-sensitized solar cells, or Graetzel cells, were discovered about 20 years ago. When they’re exposed to sunlight the dye becomes excited and creates an electronic charge without the need for pricey semiconductors. Kind of like the way plants use chlorophyll to turn sunlight into energy through photosynthesis. While the technology is the same, 3G Solar Voltaics‘ CEO Barry Breen says that being able to embed the cells on small surfaces has the potential to change the way we charge everyday devices. ) BARRY N. BREEN, CEO OF 3GSOLAR PHOTOVOLTAICS, SAYING: “What we offer in our cells, in our light power devices, is a solution that gives three times the power of anything else that exists, and we’re talking indoors, where most the electronics are used. So three times the power to run these new electronics, the new sensors, the smart watches and other wearables. So it’s a way to keep those powered that couldn’t be done before,” comments Barry Breen, CEO of 3G Solar Photovoltaics.

The small modules are durable and last for about 10 years. They can be colored and fitted to the shape of a device so they don’t stand out. Although still a prototype, the makers say the technology could make batteries a thing of the past.



How To Grow High-Efficiency Perovskite Solar Cells

Los Alamos National Laboratory researchers reveal a new solution-based hot-casting technique that allows growth of highly efficient and reproducible solar cells from large-area perovskite crystals.
State-of-the-art photovoltaics using high-purity, large-area, wafer-scale single-crystalline semiconductors grown by sophisticated, high temperature crystal-growth processes are seen as the future of efficient solar technology. Solar cells composed of organic-inorganic perovskites offer efficiencies approaching that of silicon, but they have been plagued with some important deficiencies limiting their commercial viability. It is this failure that the Los Alamos technique successfully corrects.

The researchers fabricated planar solar cells from pervoskite materials with large crystalline grains that had efficiencies approaching 18%, among the highest reported in the field of perovskite-based light-to-energy conversion devices.
peroskite solar cell

These perovskite crystals offer promising routes for developing low-cost, solar-based, clean global energy solutions for the future,” said Aditya Mohite, the Los Alamos scientist leading the project.
Characterization and modeling attribute the improved performance to reduced bulk defects and improved charge-carrier mobility in large-grain pervoskite materials,” said Mohite, “and we’ve demonstrated that the crystalline quality is on par with that observed for high-quality semiconductors like silicon and gallium arsenides.

The resuls have been published in the journal Science,


Carbon NanoTubes Solar Cells Twice More Efficient

Lighter, more flexible, and cheaper than conventional solar-cell materials, carbon nanotubes (CNTs) have long shown promise for photovoltaics. But research stalled when CNTs proved to be inefficient, converting far less sunlight into power than other methods.

Now a research team led by Mark Hersam, professor of materials science and engineering at the McCormick School of Engineering, Northwestern University, has created a new type of CNT solar cell that is twice as efficient as its predecessors. It is also the first CNT solar cell to have its performance certified by the National Renewable Energy Laboratory.

solar cells
The field had been hovering around 1 percent efficiency for about a decade; it had really plateaued,.” Hersam said. “But we’ve been able to increase it to over 3 percent. It’s a significant jump
The problem is that each nanotube chirality only absorbs a narrow range of optical wavelengths,” Hersam said. “If you make a solar cell out of a single chirality carbon nanotube, you basically throw away most of the solar light.”

Hersam’s team made a mixture of polychiral, or multiple chirality, semiconducting nanotubes. This maximized the amount of photocurrent produced by absorbing a broader range of solar-spectrum wavelengths. The cells significantly absorbed near-infrared wavelengths, a range that has been inaccessible to many leading thin-film technologies.
The research is described in the article “Polychiral Semiconducting Carbon Nanotube-Fullerene Solar Cells” in the August 7 issue of Nano Letters.

How To Turn ANYTHING Into A Solar Panel

A team of scientists at the University of Sheffield  (U.K.) is the first to fabricate perovskite solar cells using a spray-painting process – a discovery that could help cut the cost of solar electricity.  
Efficient organometal halide perovskite based photovoltaics were first demonstrated in 2012. They are now a very promising new material for solar cells as they combine high efficiency with low materials costs. The spray-painting process wastes very little of the perovskite material and can be scaled to high volume manufacturing – similar to applying paint to cars and graphic printing.

perovskite solar panel

Remarkably, this class of material offers the potential to combine the high performance of mature solar cell technologies with the low embedded energy costs of production of organic photovoltaics“, said  lead researcher Professor David Lidzey.” While most solar cells are manufactured using energy intensive materials like silicon, perovskites, by comparison, requires much less energy to make. By spray-painting the perovskite layer in air the team hope the overall energy used to make a solar cell can be reduced further”. “The best certified efficiencies from organic solar cells are around 10 per cent. “Perovskite cells now have efficiencies of up to 19 per cent. This is not so far behind that of silicon at 25 per cent – the material that dominates the world-wide solar market” , he added.


Cheaper, Lighter Solar Cells

Think those flat, glassy solar panels on your neighbour’s roof are the pinnacle of solar technology? Think again.
Researchers in the University of Toronto’s Edward S. Rogers Sr. Department of Electrical & Computer Engineering have designed and tested a new class of solar-sensitive nanoparticle that outshines the current state of the art employing this new class of technology. This new form of solid, stable light-sensitive nanoparticles, called colloidal quantum dots, could lead to cheaper and more flexible solar cells, as well as better gas sensors, infrared lasers, infrared light emitting diodes and more.

The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency,” said Sargent. “The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels.”.

This research was conducted in collaboration with Dalhousie University, King Abdullah University of Science and Technology and Huazhong University of Science and Technology.
The work, led by post-doctoral researcher Zhijun Ning and Professor Ted Sargent, was published this week in Nature Materials.

How To Produce Cheap Plastic Solar Cells

Photovoltaic devices, which tap the power of the sun and convert it to electricity, offer a green — and potentially unlimited alternative to fossil fuel use. So why haven’t solar technologies been more widely adopted?
Quite simply, “they’re too expensive,” says Ji-Seon Kim, a senior lecturer in experimental solid-state physics at Imperial College London, who, along with her colleagues, has come up with a technology that might help bring the prices down.
The scientists describe their new approach to making cheaper, more efficient solar panels in a paper in The Journal of Chemical Physics.
polymer blend morphologyThe polymer blend morphology without (left) and with (right) nanowires

To collect a lot of sunlight you need to cover a large area in solar panels, which is very expensive for traditional inorganic — usually silicon — photovoltaics,” explains Kim. The high costs arise because traditional panels must be made from high purity crystals that require high temperatures and vacuum conditions to manufacture.
A cheaper solution is to construct the photovoltaic devices out of organic compounds—building what are essentially plastic solar cells. Organic semiconducting materials, and especially polymers, can be dissolved to make an ink and then simply “printed” in a very thin layer, some 100 billionths of a meter thick, over a large area. “Covering a large area in plastic is much cheaper than covering it in silicon, and as a result the cost per Watt of electricity-generating capacity has the potential to be much lower,” she says.

Multicolored Solar Panels

Until now, designers of buildings have no choice but to use black or bluish-gray colored solar panels. With the help of thin-film technologies, researchers have now been able to turn solar cells into colorful creations.
Covering a roof or a façade with standard solar cells to generate electricity will change a building’s original appearance – and not always for the better. At present only dark solar panels are widely available on the market.
But things are changing. The physicist Kevin Füchsel, project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.- Germany – has been focusing for the last four years on nanostructured solar cells suitable for mass production as part of a junior research group funded by Germany’s Federal Ministry for Education and Research (BMBF). Together with a Fraunhofer team and scientists from the Friedrich-Schiller University in Jena, the group of optics specialists is looking for cost-effective techniques and manufacturing processes to increase both the efficiency of solar panels and the design flexibility they give architects and designers.
colorful solar panels

Not enough work has been done so far on combining photovoltaics and design elements to really do the term ‘customized photovoltaics’ justice,” says Kevin Füchsel. project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.


Extraordinary Sunlight Absorption With 1 nm-Thick Photovoltaics

Atom-thick photovoltaic sheets could pack hundreds of times more power per weight than conventional solar cells. A research team from Massuchusetts Institute of Technology (MIT) has found that an effective solar cell could be made from a stack of two one-molecule-thick materials: Most efforts at improving solar cells have focused on increasing the efficiency of their energy conversion, or on lowering the cost of manufacturing. But now MIT researchers are opening another avenue for improvement, aiming to produce the thinnest and most lightweight solar panels possible. Such panels, which have the potential to surpass any substance other than reactor-grade uranium in terms of energy produced per pound of material, could be made from stacked sheets of one-molecule-thick materials such as graphene or molybdenum disulfide.
Very thin Solar panelsGraphene (a one-atom-thick sheet of carbon atoms, shown at bottom in blue) and molybdenum disulfide (above, with molybdenum atoms shown in red and sulfur in yellow). The two sheets together are thousands of times thinner than conventional silicon solar cells.
Stacking a few layers could allow for higher efficiency, one that competes with other well-established solar cell technologies,” says Marco Bernardi, a postdoc in MIT’s Department of Materials Science who was the lead author of the paper. Maurizia Palummo, a senior researcher at the University of Rome visiting MIT through the MISTI Italy program, was also a co-author. Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, says the new approach “pushes towards the ultimate power conversion possible from a material” for solar power. Grossman is the senior author of a new paper describing this approach, published in the journal Nano Letters.

Solar Power Conversion Increases 11%

A new technique developed by University of Toronto Engineering Professor Ted Sargent and his research group could lead to significantly more efficient solar cells. The solution? Spectrally tuned, solution-processed plasmonic nanoparticles. These particles, the researchers say, provide unprecedented control over light’s propagation and absorption. The new technique developed by Sargent’s group shows a possible 35 per cent increase in the technology’s efficiency in the near-infrared spectral region, says co-author Dr. Susanna Thon. Overall, this could translate to an 11 per cent solar power conversion efficiency increase, she says, making quantum dot photovoltaics even more attractive as an alternative to current solar cell technologies.
There are two advantages to colloidal quantum dots,” Thon says. “First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum. Changing the size is very easy, and this size-tunability is a property shared by plasmonic materials: by changing the size of the plasmonic particles, we were able to overlap the absorption and scattering spectra of these two key classes of nanomaterials.