Squeeze And Get More Power Out Of Solar Cells
Physicists at the University of Warwick have published new research in the Journal Science that could literally squeeze more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. The paper entitled the “Flexo-Photovoltaic Effect” was written by Professor Marin Alexe, Ming-Min Yang, and Dong Jik Kim who are all based in the University of Warwick’s Department of Physics.
The Warwick researchers looked at the physical constraints on the current design of most commercial solar cells which place an absolute limit on their efficiency. Most commercial solar cells are formed of two layers creating at their boundary a junction between two kinds of semiconductors, p-type with positive charge carriers (holes which can be filled by electrons) and n-type with negative charge carriers (electrons). When light is absorbed, the junction of the two semiconductors sustains an internal field splitting the photo-excited carriers in opposite directions, generating a current and voltage across the junction. Without such junctions the energy cannot be harvested and the photo-exited carriers will simply quickly recombine eliminating any electrical charge. That junction between the two semiconductors is fundamental to getting power out of such a solar cell but it comes with an efficiency limit. This Shockley-Queisser Limit means that of all the power contained in sunlight falling on an ideal solar cell in ideal conditions only a maximum of 33.7% can ever be turned into electricity.
There is however another way that some materials can collect charges produced by the photons of the sun or from elsewhere. The bulk photovoltaic effect occurs in certain semiconductors and insulators where their lack of perfect symmetry around their central point (their non-centrosymmetric structure) allows generation of voltage that can be actually larger than the band gap of that material. Unfortunately the materials that are known to exhibit the anomalous photovoltaic effect have very low power generation efficiencies, and are never used in practical power-generation systems. The Warwick team wondered if it was possible to take the semiconductors that are effective in commercial solar cells and manipulate or push them in some way so that they too could be forced into a non-centrosymmetric structure and possibly therefore also benefit from the bulk photovoltaic effect.
“Extending the range of materials that can benefit from the bulk photovoltaic effect has several advantages: it is not necessary to form any kind of junction; any semiconductor with better light absorption can be selected for solar cells, and finally, the ultimate thermodynamic limit of the power conversion efficiency, so-called Shockley-Queisser Limit, can be overcome“, explains Professor Marin Alexe (University of Warwick).
Source: https://warwick.ac.uk/
Nanoscale Transistor
Flexible televisions, tablets and phones as well as ‘truly wearable’ smart tech are a step closer thanks to a nanoscale transistor created by researchers at The University of Manchester and Shandong University in China. The international team has developed an ultrafast, nanoscale transistor – known as a thin film transistor, or TFT, – made out of an oxide semiconductor. The TFT is the first oxide-semiconductor based transistor that is capable of operating at a benchmark speed of 1 GHz. This could make the next generation electronic gadgets even faster, brighter and more flexible than ever before. A TFT is a type of transistor usually used in a liquid crystal display (LCD). These can be found in most modern gadgets with LCD screens such as smart phones, tablets and high-definition televisions.
How do they work? LCD features a TFT behind each individual pixel and they act as individual switches that allow the pixels to change state rapidly, making them turn on and off much more quickly. But most current TFTs are silicon-based which are opaque, rigid and expensive in comparison to the oxide semiconductor family of transistors which the team from the UK and China are developing. Whilst oxide TFTs will improve picture on LCD displays, it is their flexibility that is even more impressive.
Aimin Song, Professor of Nanoelectronics in the School of Electrical & Electronic Engineering, The University of Manchester, explains:
“TVs can already be made extremely thin and bright. Our work may help make TV more mechanically flexible and even cheaper to produce. “But, perhaps even more importantly, our GHz transistors may enable medium or even high performance flexible electronic circuits, such as truly wearable electronics. “Wearable electronics requires flexibility and in many cases transparency, too. This would be the perfect application for our research. “Plus, there is a trend in developing smart homes, smart hospitals and smart cities – in all of which oxide semiconductor TFTs will play a key role.”
Oxide-based technology has seen rapid development when compared to its silicon counterpart which is increasingly close to some fundamental limitations. Prof Song says there has been fast progress in oxide-semiconductors in recent years and extensive efforts have been made in order to improve the speed of oxide-semiconductor-based TFTs. So much so some oxide-based technology has already started replacing amorphous silicon in some gadgets. Prof Song thinks these latest developments have brought commercialisation much closer.
Source: http://www.manchester.ac.uk/
How Solar Cells Absorb 20 % More Sunlight
Trapping light with an optical version of a whispering gallery, researchers at the National Institute of Standards and Technology (NIST) have developed a nanoscale coating for solar cells that enables them to absorb about 20 percent more sunlight than uncoated devices. The coating, applied with a technique that could be incorporated into manufacturing, opens a new path for developing low-cost, high-efficiency solar cells with abundant, renewable and environmentally friendly materials.
Illustration shows the nanoresonator coating, consisting of thousands of tiny glass beads, deposited on solar cells. The coating enhances both the absorption of sunlight and the amount of current produced by the solar cells
The coating consists of thousands of tiny glass beads, only about one-hundredth the width of a human hair. When sunlight hits the coating, the light waves are steered around the nanoscale bead, similar to the way sound waves travel around a curved wall such as the dome in St. Paul’s Cathedral in London. At such curved structures, known as acoustic whispering galleries, a person standing near one part of the wall easily hears a faint sound originating at any other part of the wall.
Using a laser as a light source to excite individual nanoresonators in the coating, the team found that the coated solar cells absorbed, on average, 20 percent more visible light than bare cells. The measurements also revealed that the coated cells produced about 20 percent more current.
Source: https://www.nist.gov/
How To Turn On Cancer-Killing Immune Cells
A remote command could one day send immune cells on a rampage against a malignant tumor. The ability to mobilize, from outside the body, targeted cancer immunotherapy inside the body has taken a step closer to becoming reality. Bioengineers at the Georgia Institute of Technology have installed a heat-sensitive switch into T-cells that can activate the T-cells when heat turns the switch on. The method, tested in mice and published in a new study, is locally targeted and could someday help turn immunotherapy into a precision instrument in the fight against cancer.
Immunotherapy has made headlines with startling high-profile successes like saving former U.S. President Jimmy Carter from brain cancer. But the treatment, which activates the body’s own immune system against cancer and other diseases, has also, unfortunately, proved to be hit-or-miss.
“In patients where radiation and traditional chemotherapies have failed, this is where T-cell therapies have shined, but the therapy is still new,” said principal investigator Gabe Kwong. “This study is a step toward making it even more effective.”
Cancer is notoriously wily, and when T-cells crawl into a tumor, the tumor tends to switch off the T-cells’ cancer-killing abilities. Researchers have been working to switch them back on.
Kwong’s remote control has done this in the lab, while also boosting T-cell activity. In the study, Kwong’s team successfully put their remote-control method through initial tests in mice with implanted tumors (so-called tumor phantoms, specially designed for certain experiments).
Source: http://www.rh.gatech.edu/
Adaptive Materials
Engineers at the U.S. Army Research Laboratory (ARL) and the University of Maryland have developed a technique that causes a composite material to become stiffer and stronger on-demand when exposed to ultraviolet light. This on-demand control of composite behavior could enable a variety of new capabilities for future Army rotorcraft design, performance and maintenance.
ARL‘s Dr. Frank Gardea, a research engineer, said the focus of the research was on controlling how molecules interact with each other. He said the aim was to “have them interact in such a way that changes at a small size, or nanoscale, could lead to observed changes at a larger size, or macroscale.”
Dr. Bryan Glaz, chief scientist of ARL‘s Vehicle Technology Directorate said “an important motivation for this work is the desire to engineer new structures, starting from the nanoscale, to enable advanced rotorcraft concepts that have been proposed in the past, but were infeasible due to limitations in current composites. One of the most important capabilities envisioned by these concepts is a significantly reduced maintenance burden due to compromises we make to fly at high speeds”, he said. The reduced scheduled maintenance of future Army aviation platforms is an important technological driver for future operating concepts.
Army researchers imagine a rotorcraft concept, which represents reactive reinforcements that when exposed to ultraviolet light will increase the mechanical behavior on-demand. The engineers said control of mechanical behavior could potentially lead to increased aerodynamic stability in rotorcraft structures.
“The enhanced mechanical properties with potentially low weight penalties, enabled by the new technique, could lead to nanocomposite based structures that would enable rotorcraft concepts that we cannot build today,” Glaz said.
The joint work, recently published in Advanced Materials Interfaces (DOI: 10.1002/admi.201800038), shows that these composite materials could become 93-percent stiffer and 35-percent stronger after a five minute exposure to ultraviolet light. The technique consists of attaching ultraviolet light reactive molecules to reinforcing agents like carbon nanotubes. These reactive reinforcing agents are then embedded in a polymer. Upon ultraviolet light exposure, a chemical reaction occurs such that the interaction between the reinforcing agents and the polymer increases, thus making the material stiffer and stronger.
ource: https://www.arl.army.mil/
How To End Malaria
Gene-editing technologies that alter mosquitoes’ DNA could prove critical in the fight against malaria, Bill Gates said on Wednesday, and ethical concerns should not block progress in such gene-modifying research.
Speaking at the Malaria Forum conference in London, the billionaire Microsoft co-founder and philanthropist said that while gene editing raises “legitimate questions”, that should not jeopardize exploration of tools such as CRISPR gene editing and so-called “gene drive” technologies.
“I’m very energized about the potential of gene drive. (It’s) the kind of breakthrough we need to support,” Gates said. “It may prove critical here.”
Gene drive technologies alter DNA and drive self-sustaining genetic changes through multiple generations by overriding normal biological processes. CRISPR technology enables scientists to find and modify or replace virtually any gene. The techniques are being explored across science – from human medicine to livestock– and crop-breeding. In mosquitoes that transmit malaria, genetic alterations can be used to induce infertility to reduce populations, or alter the insects’ ability to carry and pass on the malaria parasite.
The technologies can be extremely powerful, but they are also controversial, since such genetically engineered organisms released into the environment could have an unknown and irreversible impact on the ecosystem. Asked in a interview with Reuters about that controversy, Gates said there were understandable concerns about safety and efficacy that would need to be addressed in research and trials. But he countered: “Malaria itself is quite controversial – it kills about 400,000 kids a year. So we’re definitely not on the side of malaria.”
He also noted that at their summit in January, leaders of the African Union endorsed gene drive research as part of the fight against a disease that continues to kill their people.
Source: https://www.reuters.com/
Tool Speeds Up Manufacturing Of Powered Wearable
People could soon power items such as their mobile phones or personal health equipment by simply using their daily movements, thanks to a new research tool that could be used by manufacturers.
In a new paper published by Nano Energy, experts from the Advanced Technology Institute (ATI) at the University of Surrey (UK) detail a new methodology that allows designers of smart-wearables to better understand and predict how their products would perform once manufactured and in use.
The technology is centred on materials that become electrically charged after they come into contact with each other, known as triboelectric materials – for example, a comb through hair can create an electrical charge. Triboelectric Nanogenerators (TENGs), use this static charge to harvest energy from movement through a process called electrostatic induction. Over the years, a variety of TENGs have been designed which can convert almost any type of movement into electricity. The University of Surrey’s tool gives manufacturers an accurate understanding of the output power their design would create once produced.
This follows the news earlier this year of the ATI announcing the creation of its £4million state-of-the-art Nano-Manufacturing Hub. The new facility will produce plastic nanoscale electronics for wearable sensors, electronic tags and other electronic devices.
Ishara Dharmasena, lead scientist on this project from the University of Surrey, said: “The future global energy mix will depend on renewable energy sources such as solar power, wind, motion, vibrations and tidal. TENGs are a leading technology to capture and convert motion energy into electricity, extremely useful in small scale energy harvesting applications. Our work will, for the first time, provide universal guidance to develop, compare and improve various TENG designs. We expect this technology in household and industrial electronic products, catering to a new generation of mobile and autonomous energy requirements.”
Source: https://www.surrey.ac.uk/
Plastic-Eating Enzyme
Scientists have engineered an enzyme which can digest some of our most commonly polluting plastics, providing a potential solution to one of the world’s biggest environmental problems. The discovery could result in a recycling solution for millions of tonnes of plastic bottles, made of polyethylene terephthalate, or PET, which currently persists for hundreds of years in the environment. The research was led by teams at the University of Portsmouth and the US Department of Energy’s National Renewable Energy Laboratory (NREL) and is published in Proceedings of the National Academy of Sciences (PNAS).
Professor John McGeehan at the University of Portsmouth and Dr Gregg Beckham at NREL solved the crystal structure of PETase—a recently discovered enzyme that digests PET— and used this 3D information to understand how it works. During this study, they inadvertently engineered an enzyme that is even better at degrading the plastic than the one that evolved in nature. The researchers are now working on improving the enzyme further to allow it to be used industrially to break down plastics in a fraction of the time.
CLICK ON THE IMAGE TO ENJOY THE VIDEO
“Few could have predicted that since plastics became popular in the 1960s huge plastic waste patches would be found floating in oceans, or washed up on once pristine beaches all over the world. “We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these ‘wonder-materials’, must now use all the technology at their disposal to develop real solutions,” said Professor McGeehan, Director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth,
Source: http://uopnews.port.ac.uk/
The Zero Bills Home
The Zero Bills Home build at the BRE Innovation Park in UK represents the first show home for a new 96 home zero bills development in Newport Essex for the Sir Arthur Ellis family Trust. Newport is 8 miles from Stansted and 15 miles from Cambridge. The new zero bills village is 150 yards from a station on the Bishopsgate / Cambridge railway line.
CLICK ON THE IMAGE TO ENJOY THE VIDEO
Superinsulated concrete foundation slab with optional additional piles to match most ground conditions.Laser cut galv steelpowder coated structural ring beam with C16 UK timber studs. UK fabricated OSB structural boards enables one floor to be built every two days. Superinsulated cladding with heat recovery ventilation and triple glazing reduces heat demand to the point where a tiny heat pump can provide comfort and hot water. ZED Factory designed BIPV solar roofing system provides durable roof with electric generation and optional solar loft conservatory. Good daylight, water saving appliances and LED lighting reduces electric demand allowing surplus solar electricity to power an electric car. A smart LIPO4 Fitcraft battery system, positioned under the stair stores solar electricity, minimising grid imports and limiting grid export to 3kW maximum avoids the need to upgrade the existing mains grid infrastructure. The system enables simple, adaptable plans which create convenient internal layouts for any plot orientation.
The system build costs at scale are circa £1450- £1650/ m2 (around 1500 euros/m2) for a completed building which compares favourably with current costs of meeting building regulations. Combined with no net annual energy bills and the potential to achieve higher resale values based on the additional features of the building, the ZBH system offers a cost effective and sustainable alternative to traditional builder offerings.
Source: https://www.zedfactory.com/
Human Internal Verbalizations Understood Instantly By Computers
MIT researchers have developed a computer interface that can transcribe words that the user verbalizes internally but does not actually speak aloud. The system consists of a wearable device and an associated computing system. Electrodes in the device pick up neuromuscular signals in the jaw and face that are triggered by internal verbalizations — saying words “in your head” — but are undetectable to the human eye. The signals are fed to a machine-learning system that has been trained to correlate particular signals with particular words. The device also includes a pair of bone-conduction headphones, which transmit vibrations through the bones of the face to the inner ear. Because they don’t obstruct the ear canal, the headphones enable the system to convey information to the user without interrupting conversation or otherwise interfering with the user’s auditory experience.
The device is thus part of a complete silent-computing system that lets the user undetectably pose and receive answers to difficult computational problems. In one of the researchers’ experiments, for instance, subjects used the system to silently report opponents’ moves in a chess game and just as silently receive computer-recommended responses.
“The motivation for this was to build an IA device — an intelligence-augmentation device,” says Arnav Kapur, a graduate student at the MIT Media Lab, who led the development of the new system. “Our idea was: Could we have a computing platform that’s more internal, that melds human and machine in some ways and that feels like an internal extension of our own cognition?” “We basically can’t live without our cellphones, our digital devices,” adds Pattie Maes, a professor of media arts and sciences and Kapur’s thesis advisor. “But at the moment, the use of those devices is very disruptive. If I want to look something up that’s relevant to a conversation I’m having, I have to find my phone and type in the passcode and open an app and type in some search keyword, and the whole thing requires that I completely shift attention from my environment and the people that I’m with to the phone itself. So, my students and I have for a very long time been experimenting with new form factors and new types of experience that enable people to still benefit from all the wonderful knowledge and services that these devices give us, but do it in a way that lets them remain in the present.”
Source: http://news.mit.edu/
Revolutionary NanoDrops Replace Glasses
Israeli scientists and clinicians appear to have come up with “revolutionary” eye-drops that can correct short– or long-sightedness and eliminate the need for glasses. The so-called ‘nano-drops’ have been developed by a team at Sha’are Zedek Medical Center and Bar-Ilan University’s Institute of Nanotechnology and Advanced Materials.
They have been shown to improve both short-sightedness (myopia) and long-sightedness (hyperopia) in tests on pigs, with plans to begin clinical testing on humans later this year.
If the drops are found to improve human vision then the nano-drops solution could eliminate the need for glasses and “revolutionise ophthalmological and optometry treatment”.
Prospective patients would use a smartphone app to scan their eyes, measure their refraction, create a laser pattern then apply a “laser corneal stamping” of an optical pattern onto the corneal surface of their eyes.
Taiwanese Electric SuperCar Aims To Take On Tesla
Hailed as the world’s first electric supercar with onroad and offroad capabilities, the “Miss R” is the company’s electric vehicle (EV) designed for serious performance driving. Harnessing a four-wheel torque vectoring system capable of launching it at roughly 168 MPH (270 km/h), 4 independent electric motors rated at 350V each will give the Miss R the edge over Tesla’s future Roadster 2.0 (base version). The 0–60 MPH will be covered in 1.8 seconds and the 0–124 MPH (200 km/h) in a blistering 5.1 seconds.
CLICK ON THE IMAGE TO ENJOY THE VIDEO
What makes the Electric Supercar XING Mobility Miss R different from other high-end performance EVs is that it is designed to reach that performance on almost any road surface. On-road, on-track, and off-road is the leitmotiv of the company that wants to offer a versatile driving experience no matter what the pavement.
According to XING Mobility’s Co-founder and CEO, Royce YC Hong: “Miss R is the embodiment of the paradigm shift of EVs surpassing traditional combustion-engine cars in both performance and capability. The core idea behind the prototype is to achieve game-changing performance levels and driving experiences that are otherwise impossible to achieve in a gasoline-powered vehicle.” Indeed, XING Mobility is out to prove once and for all that the electric drivetrain is far superior to its contemporary internal combustion engine (ICE) cousin.
Source: https://www.xingmobility.com/
Ultra-Powerful Batteries
From smartphones to electric vehicles, many of today’s technologies run on lithium ion batteries. That means that consumers have to keep their chargers handy. An iPhone X battery only lasts for 21 hours of talk time, and Tesla’s model S has a 335-mile range—which means you could expect to make it from Newark, Delaware to Providence, Rhode Island, but not all the way to Boston, on one charge. Scientists all over the world—including even the inventor of lithium ion batteries himself, John Goodenough—are looking for ways to make rechargeable batteries safer, lighter, and more powerful.
Now, an international team of researchers led by Bingqing Wei, a professor of mechanical engineering at the University of Delaware and the director of the Center for Fuel Cells and Batteries, is doing work that could lay the foundation for more widespread use of lithium metal batteries, which have more capacity than the lithium ion batteries commonly used in consumer electronics today. The team developed a method to mitigate dendrite formation in lithium metal batteries, which they have described in a paper published in Nano Letters.
In a lithium ion battery, the anode, or current-generating side, is made of a material, such as graphite, with lithium ions bound to it. The lithium ions flow to the cathode, or current-collecting side.
In a lithium metal battery, the anode is made of lithium metal. Electrons flow from the anode to the cathode to generate electricity. Rechargeable batteries made of lithium metal hold a lot of promise because lithium is the most electrically positive metal and has a very high capacity.
“Theoretically, lithium metal is one of the best choices for batteries, but it is hard to handle in practice,” Wei said.
Lithium metal batteries have been inefficient, unstable, and even a fire hazard thus far. Their performance is hampered by lithium dendrites, formations that look like tiny stalagmites made of lithium deposits. As a battery is being used, lithium ions collect on the anode. Over time, the lithium deposits become non-uniform, leading to the formations of these dendrites, which can cause the battery to short circuit.
Source: http://www.udel.edu/
