Brown University: Researchers Make New Silicon-Based Nanomaterials: Electronics Applications


Semiconductor IIIIChemists from Brown University have found a way to make new 2D, graphene-like semiconducting nanomaterials using an old standby of the semiconductor world: silicon.

In a paper published in the journal Nanoletters, the researchers describe methods for making nanoribbons and nanoplates from a compound called silicon telluride. The materials are pure, p-type semiconductors (positive charge carriers) that could be used in a variety of electronic and optical devices. Their layered structure can take up lithium and magnesium, meaning it could also be used to make electrodes in those types of batteries.

“Silicon-based compounds are the backbone of modern electronics processing,” said Kristie Koski, assistant professor of chemistry at Brown, who led the work.

“Silicon telluride is in that family of compounds, and we’ve shown a totally new method for using it to make layered, two-dimensional nanomaterials.”

Koski and her team synthesised the new materials through vapour deposition in a tube furnace. When heated in the tube, silicon and tellurium vaporise and react to make a precursor compound that is deposited on a substrate by an argon carrier gas. The silicon telluride then grows from the precursor compound.

Different structures can be made by varying the furnace temperature and using different treatments of the substrate. By tweaking the process, the researchers made nanoribbons that are about 50 to 1000 nm in width and about 10 microns long. They also made nanoplates flat on the substrate and standing upright.

“We see the standing plates a lot,” Koski said. “They’re half hexagons sitting upright on the substrate. They look a little like a graveyard.”

Each of the different shapes has a different orientation of the material’s crystalline structure. As a result, they all have different properties and could be used in different applications. The researchers also showed that the material can be ‘doped’ through the use of different substrates. Doping is a process through which tiny impurities are introduced to change a material’s electrical properties. In this case, the researchers showed that silicon telluride can be doped with aluminium when grown on a sapphire substrate. That process could be used, for example, to change the material from a p-type semiconductor (one with positive charge carriers) to an n-type (one with negative charge carriers).

The materials are not particularly stable out in the environment, Koski said, but that’s easily remedied. “What we can do is oxidise the silicon telluride and then bake off the tellurium, leaving a coating of silicon oxide,” she said. “That coating protects it and it stays pretty stable.”

From here, Koski and her team plan to continue testing the material’s electronic and optical properties. They’re encouraged by what they’ve seen so far. “We think this is a good candidate for bringing the properties of 2D materials into the realm of electronics,” Koski said.

Koski’s co-authors on the paper were postdoctoral researcher Sean Keuleyan, graduate student Mengjing Wang and undergraduates Frank Chung and Jeffrey Commons.

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Rice University: Silicon Oxide Memories Catch Manufacturers’ Eye


Rice U Silicon Oxide 49797Rice’s silicon oxide memories catch manufacturers’ eye: Use of porous silicon oxide reduces forming voltage, improves manufacturability

Houston, TX | Posted on July 10th, 2014

Rice University’s breakthrough silicon oxide technology for high-density, next-generation computer memory is one step closer to mass production, thanks to a refinement that will allow manufacturers to fabricate devices at room temperature with conventional production methods.

First discovered five years ago, Rice’s silicon oxide memories are a type of two-terminal, “resistive random-access memory” (RRAM) technology. In a new paper available online in the American Chemical Society journal Nano Letters, a Rice team led by chemist James Tour compared its RRAM technology to more than a dozen competing versions.

“This memory is superior to all other two-terminal unipolar resistive memories by almost every metric,” Tour said. “And because our devices use silicon oxide — the most studied material on Earth — the underlying physics are both well-understood and easy to implement in existing fabrication facilities.” Tour is Rice’s T.T. and W.F. Chao Chair in Chemistry and professor of mechanical engineering and nanoengineering and of computer science.

Tour and colleagues began work on their breakthrough RRAM technology more than five years ago. The basic concept behind resistive memory devices is the insertion of a dielectric material — one that won’t normally conduct electricity — between two wires. When a sufficiently high voltage is applied across the wires, a narrow conduction path can be formed through the dielectric material.

The presence or absence of these conduction pathways can be used to represent the binary 1s and 0s of digital data. Research with a number of dielectric materials over the past decade has shown that such conduction pathways can be formed, broken and reformed thousands of times, which means RRAM can be used as the basis of rewritable random-access memory.

RRAM is under development worldwide and expected to supplant flash memory technology in the marketplace within a few years because it is faster than flash and can pack far more information into less space. For example, manufacturers have announced plans for RRAM prototype chips that will be capable of storing about one terabyte of data on a device the size of a postage stamp — more than 50 times the data density of current flash memory technology.

The key ingredient of Rice’s RRAM is its dielectric component, silicon oxide. Silicon is the most abundant element on Earth and the basic ingredient in conventional microchips. Microelectronics fabrication technologies based on silicon are widespread and easily understood, but until the 2010 discovery of conductive filament pathways in silicon oxide in Tour’s lab, the material wasn’t considered an option for RRAM.

Since then, Tour’s team has raced to further develop its RRAM and even used it for exotic new devices like transparent flexible memory chips. At the same time, the researchers also conducted countless tests to compare the performance of silicon oxide memories with competing dielectric RRAM technologies.

“Our technology is the only one that satisfies every market requirement, both from a production and a performance standpoint, for nonvolatile memory,” Tour said. “It can be manufactured at room temperature, has an extremely low forming voltage, high on-off ratio, low power consumption, nine-bit capacity per cell, exceptional switching speeds and excellent cycling endurance.”

Rice U Silicon Oxide 49797

This scanning electron microscope image and schematic show the design and composition of new RRAM memory devices based on porous silicon oxide that were created at Rice University.

Credit: Tour Group/Rice University

In the latest study, a team headed by lead author and Rice postdoctoral researcher Gunuk Wang showed that using a porous version of silicon oxide could dramatically improve Rice’s RRAM in several ways. First, the porous material reduced the forming voltage — the power needed to form conduction pathways — to less than two volts, a 13-fold improvement over the team’s previous best and a number that stacks up against competing RRAM technologies. In addition, the porous silicon oxide also allowed Tour’s team to eliminate the need for a “device edge structure.”

“That means we can take a sheet of porous silicon oxide and just drop down electrodes without having to fabricate edges,” Tour said. “When we made our initial announcement about silicon oxide in 2010, one of the first questions I got from industry was whether we could do this without fabricating edges. At the time we could not, but the change to porous silicon oxide finally allows us to do that.”

Wang said, “We also demonstrated that the porous silicon oxide material increased the endurance cycles more than 100 times as compared with previous nonporous silicon oxide memories. Finally, the porous silicon oxide material has a capacity of up to nine bits per cell that is highest number among oxide-based memories, and the multiple capacity is unaffected by high temperatures.”

Tour said the latest developments with porous silicon oxide — reduced forming voltage, elimination of need for edge fabrication, excellent endurance cycling and multi-bit capacity — are extremely appealing to memory companies.

“This is a major accomplishment, and we’ve already been approached by companies interested in licensing this new technology,” he said.

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Study co-authors — all from Rice — include postdoctoral researcher Yang Yang; research scientist Jae-Hwang Lee; graduate students Vera Abramova, Huilong Fei and Gedeng Ruan; and Edwin Thomas, the William and Stephanie Sick Dean of Rice’s George R. Brown School of Engineering, professor in mechanical engineering and materials science and in chemical and biomolecular engineering.

Graphene-based discs ensure safe storage


Graphene-based discs ensure safe storage

(Phys.org) —Swinburne University of Technology researchers have shown the potential of a new material for transforming secure optical information storage.

In their latest research paper published in Scientific Reports, researchers Xiangping Li, Qiming Zhang, Xi Chen and Professor Min Gu demonstrated the potential to record holographic coding in a polymer composite.

“Conventionally, information is recorded as binary data in a disc. If the disc is broken, the information cannot be retrieved,” Director of the Centre for Micro-Photonics at Swinburne, Professor Min Gu, said.

“This is a major operation cost in big data centres, which consist of thousands of disc arrays with multiple physical duplicates of data. The new material allows the development of super-discs, which will enable information to be retrieved – even from broken pieces.”

Graphene oxide is similar to graphene, discovered by Andre Geim and Konstantin Novoselov, who received the 2010 Nobel Prize in Physics for this groundbreaking discovery. Graphene is very strong, light, flexible, nearly transparent, and is an excellent conductor of heat and electricity.

Graphene oxide has similar properties, but also has a fundamental fluorescent property that can be used in bioimaging and for multimode optical recording.

By focusing an ultrashort laser beam onto the graphene oxide polymer, the researchers created a 10-100 times increase in the of the graphene oxide along with a decrease in its fluorescence. (The refractive index is the measure of the bending of light as it passes through a medium.)

“The unique feature of the giant refractive-index modulation together with the fluorescent property of the graphene oxide polymer offers a new mechanism for multimode optical recording,” Professor Gu said.

To demonstrate the feasibility of the mechanism, the researchers encoded the image of a kangaroo in a computer generated hologram. The hologram was then rendered as a three-dimensional recording to the graphene oxide polymer. The encrypted patterns in the hologram could not be seen as a normal microscope image, but could be retrieved in the diffracted mode.

“The giant refractive index of this material shows promise for merging data storage with holography for security coding,” Professor Gu said.

“This exciting feature not only boosts the level of storage security, but also helps to reduce the operation costs of big data centres that rely on multiple physical duplicates to avoid data loss.”

The researchers say it could also revolutionise flat screen TV and solar cell technology.

“More importantly, graphene has been deemed as a revolutionary replacement for silicon, which is the platform for current information technologies based on electronics,” Dr Xiangping Li said.

“The giant refractive index we discovered shows the promise of to merge electronics and photonics for the platform of the next generation information technologies.”

Read more at: http://phys.org/news/2013-10-graphene-based-discs-safe-storage.html#jCp

Read more at: http://phys.org/news/2013-10-graphene-based-discs-safe-storage.html#jCp

Sun Plus Nanotechnology: Can Solar Energy Get Bigger by Thinking Small?


QDOTS imagesCAKXSY1K 8

Patrick J. Kiger

For National Geographic News

Published April 28, 2013

“Advances in nanotechnology will lead to higher efficiencies and lower costs, and these can and likely will be significant,” explains Matt Beard, a senior scientist for the U.S. Department of Energy‘s National Renewable Energy Laboratory (NREL). “In fact, nanotechnology is already having dramatic effects on the science of solar cells.”

 

Nearly 60 years after researchers first demonstrated a way to convert sunlight into energy, science is still grappling with a critical limitation of the solar photovoltaic cell.

It just isn’t that efficient at turning the tremendous power of the sun into electricity.

And even though commercial solar cells today have double to four times the 6 percent efficiency of the one first unveiled in 1954 by Bell Laboratories in New Jersey, that hasn’t been sufficient to push fossil fuel from its preeminent place in the world energy mix.

But now, alternative energy researchers think that something really small—nanotechnology, the engineering of structures a fraction of the width of a human hair—could give a gigantic boost to solar energy. (Related Quiz: “What You Don’t Know About Solar Power“)

“Advances in nanotechnology will lead to higher efficiencies and lower costs, and these can and likely will be significant,” explains Matt Beard, a senior scientist for the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL). “In fact, nanotechnology is already having dramatic effects on the science of solar cells.”

Of course, the super-expensive solar arrays used in NASA’s space program are far more efficient than those installed on rooftops. (Related: “Beam It Down: A Drive to Launch Space-Based Solar“) And in the laboratory, scientists have achieved record-breaking efficiencies of more than 40 percent. But such contests are a testament to the gap between solar potential and the mass market cells of today.

 

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The light glinting off the surface of this solar photovoltaic cell signifies lost efficiency. Scientists are looking to nanotechnology to boost solar power, including by reducing the amount of sunlight that silicon wastes through reflection.

The power output of the Sun that reaches the Earth could provide as much as 10,000 times more energy than the combined output of all the commercial power plants on the planet, according to the National Academy of Engineering. The problem is how to harvest that energy.

Today’s commercial solar cells, usually fashioned from silicon, are still relatively expensive to produce (even though prices have come down), and they generally manage to capture only 10 to 20 percent of the sunlight that strikes them. This contributes to the high cost of solar-generated electricity compared to power generated by conventional fossil-fuel-burning plants. By one comparative measure, the U.S. Energy Information Administration estimated the levelized cost of new solar PV as of 2012 was about 56 percent higher than the cost of generation from a conventional coal plant.

Nanotechnology may provide an answer to the efficiency problem, by tinkering with solar power cells at a fundamental level to boost their ability to convert sunlight into power, and by freeing the industry to use less expensive materials. If so, it would fulfill the predictions of some of nanotechnology’s pioneers, like the late Nobel physicist Richard Smalley, who saw potential in nanoscale engineering to address the world’s energy problems. (See related: “Nano’s Big Future“) Scientists caution that there’s still a lot of work ahead to overcome technical challenges and make these inventions ready for prime time. For example, more research is needed on the environmental, health, and safety aspects of nano-materials, said the National Academy of Sciences in a 2012 report that looked broadly at nanotechnology, not at solar applications in particular. (Related Pictures: “Seven Ingredients for Better Car Batteries.”)

But Luke Henley, a University of Illinois at Chicago chemistry professor who received a 2012 National Science Foundation grant to develop a solar-related nanotechnology project, predicts there will be major advances over the next five to 10 years. “It’s potentially a game changer,” he says. Here are five intriguing recent nanotechnology innovations that could help to boost solar power.

Billions of Tiny Holes

To reduce the amount of sunlight that is reflected away from silicon solar cells and wasted, manufacturers usually add one or more layers of antireflective material, which significantly boosts the cost. But late last year, NREL scientists announced a breakthrough in the use of nanotechnology to reduce the amount of light that silicon cells reflect. It involves using a liquid process to put billions of nano-sized holes in each square inch of a solar cell’s surface. Since the holes are smaller than the light wavelengths hitting them, the light is absorbed rather than reflected. The new material, which is called “black silicon,” is nearly 20 percent more efficient than existing silicon cell designs. (Related photos: “Spanish Solar Energy“)

The “Nano Sandwich”

Organic solar cells, made from elements such as carbon, nitrogen, and oxygen that are found in living things, would be cheaper and easier to make than current silicon-based solar cells. The tradeoff, until now, is that they haven’t been as efficient. But a team of Princeton University researchers, led by electrical engineer Stephen Chou, has been able to nearly triple the efficiency of solar cells by devising a nanostructured “sandwich” of metal and plastic. In technical lingo, their invention is called a plasmodic cavity with subwavelength hole array, or PlaSCH. It consists of a thin strip of plastic sandwiched between a top layer made from an incredibly fine metal mesh and a bottom layer of the metal film used in conventional solar cells.

All aspects of the solar cell’s structure—from its thickness to the spacing of the mesh and diameter of the holes—are smaller than the wavelength of the light that it collects. As a result, the device absorbs most of the light in that frequency rather than reflecting it. “It’s like a black hole for light,” Chou explained in a Princeton press release in December. “It traps it.” Another plus: researchers say the PlaSCH cells can be manufactured cost-effectively in sheets, using a process developed by Chou years ago that embosses the nanostructures over a large area, similar to the way newspapers are printed.

Mimicking Evolution

One of the big difficulties in coming up with more energy-efficient solar cells is the limitations of the researchers’ own imaginations. But in a January 2013 article published in Scientific Reports, Northwestern University mechanical engineering professor Wei Chen and graduate student Cheng Sun introduced a method that might be superior to human brainstorming. Using a mathematical search algorithm based on natural biological evolution, they took dozens of design elements and then “mated” them over a series of 20 generations, in a process that mimicked the evolutionary principles of crossover and genetic mutation.

“Our approach is based upon the biologically evolutionary process of survival of the fittest,” Chen explained in an article on Northwestern University’s website.

The result: An evolution-inspired organic solar cell—that is, one that uses carbon-based materials rather than silicon crystals–in which light first enters a 100-nanometer-thick scattering layer with an unorthodox geometric pattern. The researchers say this should enable it to absorb light more efficiently. The U.S. Department of Energy’s Argonne National Laboratory will fabricate an actual working version of the new cell for testing.

Tiny Antennae

We’re used to thinking of solar energy as something that we collect with panels. But even the latest-generation silicon panels can take in light from only a relatively narrow range of frequencies, amounting to about 20 percent of the available energy in the sun’s rays. The panels then require separate equipment to convert the stored energy to useable electricity. But researchers at the University of Connecticut and Penn State  are working on an entirely new approach, using tiny, nanoscale antenna arrays, which would take in a wider range of frequencies and collect about 70 percent of the available energy in sunlight. Additionally, the antenna arrays themselves could convert that energy to direct current, without need for additional gear.

Scientists have been thinking about using tiny antennae for a while, but until recently, they lacked the technology make them work, since such a setup would require electrodes that were just one or two nanometers apart—about 1/30,000 the width of a human hair. Fortunately, University of Connecticut engineering professor Brian Willis has developed a fabrication technique called selective area atomic-layer deposition, which makes it possible to coat the electrodes with layers of individual copper atoms, until they are separated by just 1.5 nanometers. “This new technology could get us over the hump and make solar energy cost-competitive with fossil fuels,” Willis explained in February. “This is brand new technology, a whole new train of thought.”

Solar-Collecting Paint

No matter what sort of solar energy-collecting technology you employ, there’s still the problem of building a bunch of the devices and hooking them up in places with sun exposure. But University of Southern California chemistry professor Richard L. Brutchey and postdoctoral researcher David H. Webber have devised a technology that could turn a building into a solar collector.

They’ve created a stable, electricity-conducting liquid filled with solar-collecting nanocrystals, which can be painted or printed like an ink onto surfaces such as window glass or plastic roof panels. The nanocrystals, made of cadmium selenide instead of silicon, are about four nanometers in size—about 250 billion of them could fit on the head of a pin—so they are capable of floating in a liquid solution.  (Related Pictures: “A New Hub for Solar Tech Blooms in Japan“)

Brutchey’s and Webber’s secret to getting the technology to work? Finding an organic molecule that could attach to the nanocrystals and stabilize them and prevent them from sticking together, without hindering their ability to conduct electricity.

The researchers aim to work on nanocrystals built from materials other than cadmium, a toxic metal. “While the commercialization of this technology is still years away, we see a clear path forward toward integrating this into the next generation of solar cell technologies,” Brutchey says. (Related video: “Toxic Land Generates Solar Power“)

Quantum Dot Mass Production Breakthrough Achieved


PRNewswire/ — An Advanced Materials emerging Nanotechnology company has announced a new microreactor and software controlled continuous flow process has been successfully developed and operated for delivery of mass produced quantum dots. This new quantum dot production process replaces batch synthesis and has potential for high improvement in both yield and conversion. Tetrapod Quantum Dots are used in a variety of emerging applications including solid state lighting, QLED displays, nanobio applications and for 3rd Generation solar cells in solar panels. QD-Tetrapods have proven to have superior performance characteristics surpassing spherical nanoparticles in a number of nano-applications including Nano-Bio (delivery) and Nano-Solar (increased harvesting and efficiencies).

The inherent design of the microreactor allows for commercial-scale 0f parallel modules to achieve large production rates in a regulated, optimized system. This breakthrough production process enables both the low cost, high volume production of quantum dots, and also provides flexibility in the choice of materials used to produce the quantum dots including heavy metal free (Cadmium Free) quantum dots and other biologically inert materials.

Quantum dots have been widely recognized for their potential in next generation display technologies, solar cells, LEDs, OLEDs, computer memory, printed electronics and a vast array of security, biomedical and energy storage applications. According to research group BCC Research, the 2010 global market for quantum dots was estimated $67 million in revenues, and is projected to grow quickly over the next 5 years at greater than 50% per year reaching almost $670 million by 2015. The nanomaterials enabled market grew to $263 billion USD in 2012.

For the first time this technology offers to manufacturers that it is now realistic to test the advantages of quantum dots to establish higher performance benchmarks across a number of industries and product applications. Many discoveries and commercial applications have been developmentally slowed by the lack of high quality and consistent quantum dots. Correspondingly high costs, have also proved to be a barrier to entry and development of otherwise commercially poised nanomaterials enabled applications. This technology removes the roadblock from widespread adoption of the quantum dot as a basic building block of technology and services much like the silicon chip that has ubiquitously advanced corporate function and consumer lifestyles worldwide.

“Our goal from the onset has been to achieve a production rate of 100kg per day with a 95% or greater yield,” according to the Founder and CEO. He added that “with this breakthrough we have coupled two disruptive technologies resulting in the potential to now achieve that goal.”

According to the company’s internationally recognized CTO,  “Besides the scalability indicated, in my opinion, the truly remarkable accomplishment in this breakthrough is its adaptability to other inorganic metals and elements, including cadmium-free Quantum Dots.”

The Company has a steadfast vision that advanced technology is the solution to global issues related to cost, efficiency and increasing energy usage. Quantum dot semiconductors enable a new level of performance in a wide array of established consumer and industrial products, including low cost flexible solar cells, low power lighting and displays and biomedical research applications.

The Company intends to invigorate these markets through cost reduction and moving laboratory discovery to commercialization with volume manufacturing methods to establish a growing line of innovative high performance products.

Safe Harbor statement under the Private Securities Litigation Reform Act of 1995

This press release contains forward-looking statements that involve risks and uncertainties concerning our business, products, and financial results. Actual results may differ materially from the results predicted. More information about potential risk factors that could affect our business, products, and financial results are included in our annual report and in reports subsequently filed by us with the Securities and Exchange Commission (“SEC”). All documents are available through the SEC’s Electronic Data Gathering Analysis and Retrieval System (EDGAR) at http://www.sec.gov/ or from our website. We hereby disclaim any obligation to publicly update the information provided above, including forward-looking statements, to reflect subsequent events or circumstances.

Scientists “clone” carbon nanotubesto unlock electronic potential


Scientists “clone” carbon nanotubesto unlock electronic potential
Wed, 11/14/2012 – 1:14pm
The heart of the computer industry is known as “Silicon Valley” for a reason. Integrated circuit computer chips have been made from silicon since computing’s infancy in the 1960s. Now, thanks to a team of USC researchers, carbon nanotubes may emerge as a contender to silicon’s throne. Scientists and industry experts have long speculated that carbon nanotube transistors would one day replace their silicon predecessors.In 1998, Delft University built the world’s first carbon nanotube transistors—carbon nanotubes have the potential to be far smaller,faster, and consume less power than silicon transistors.
A key reason carbon nanotubes are not in your computer right now isthat they are difficult to manufacture in a predictable way. Scientists have had a difficult time controlling the manufacture of nanotubes to the correct diameter, type and ultimately chirality, factors that control nanotubes’ electrical and mechanical properties. Think of chirality like this: if you took a sheet of notebook paper and rolled it straight up into a tube, it would have a certain chirality. If you rolled that same sheet up at an angle,it would have a different chirality. In this example, the notebook paper represents a sheet of latticed carbon atoms that are rolled-up to create a nanotube. 
A team led by Professor Chongwu Zhou of the USC Viterbi School of Engineering and Ming Zheng of the National Institute of Standards and  Technology in Maryland solved the problem by inventing a system that consistently produces carbon nanotubes of a predictable diameter and chirality. Zhou worked with his group members Jia Liu, Chuan Wang, Bilu Liu,Liang Chen, and Ming Zheng and Xiaomin Tu of the National Institute of Standards and Technology in Maryland. “Controlling the chirality of carbon nanotubes has been a dream for many researchers.
Now the dream has come true.” said Zhou. The team has already patented its innovation, and its research will be published Nov. 13 in Nature Communications. Carbon nanotubes are typically grown using a chemical vapor deposition (CVD) system in which a chemical-laced gas is pumped intoa chamber containing substrates with metal catalyst nanoparticles,upon which the nanotubes grow. It is generally believed that the diameters of the nanotubes are determined by the size of the catalytic metal nanoparticles. However, attempts to control the catalysts in hopes of achieving chirality-controlled nanotube growth have not been successful. The USC team’s innovation was to jettison the catalyst and instead plant pieces of carbon nanotubes that have been separated and pre-selected based on chirality, using a nanotube separation technique developed and perfected by Zheng and his coworkers at NIST. Usingthose pieces as seeds, the team used chemical vapor deposition toextend the seeds to get much longer nanotubes, which were shown to have the same chirality as the seeds.. The process is referred to as “nanotube cloning.” The next steps in the research will be to carefully study the mechanism of the nanotubeg rowth in this system, to scale up the cloning process to get large quantities of chirality-controlled nanotubes, and to use those nanotubes for electronic applications. Funding of the USC team for this research came from the Semiconductor Research Corporation’s Focus Research Program Functional Engineered Nano Architectonics center and the Office of Naval Research.

The potentially world-changing research that no one knows about


Foresight Nanotech Institute Logo

 

Imagine that there exists a two-dimensional (single-layer) crystal that is made of a commonly available element, is stronger than steel yet lighter weight and flexible, displays ballistic electron mobility (for comparison, two orders of magnitude greater mobility than silicon, at room temperature), and is sufficiently optically active to see with the naked eye (though far more practically, using an optical microscope). Prospective applications include flexible, high-speed electronic devices and new composite materials for aircraft.

 

Would this sound like a potentially world-changing substance worthy of scientific attention and funding?

That substance is graphene, a single layer of graphite with hexagonally arranged carbon atoms (visualized as chicken wire).

 

Now imagine that the mechanical properties of this substance aren’t measured yet, as was the case for graphene before 2009. Imagine further that there is no way to grow or isolate the single-layer crystals in their free state, as was the case for graphene before 2004. Stepping back in time yet further, imagine that the theoretical work predicting massless charge carrier behavior hasn’t been carried out yet, as was the case for graphene before 1984.

 

Peeling back these milestones, we can see that if the scientific question being asked is “What can be realized from here?” then the graphene timeline played out characteristically, with major advancements coming primarily from opportunity-based research. In other words, over 50+ years, from the initial theoretical work on graphene in 1947 until stable monolayers were achieved in 2004, there was limited vision of what end-goals might be achievable and limited drive to get there.

 

What happens when a different question is asked, specifically “What can be realized according to physical law?” This is the key premise of the exploratory engineering approach, a methodology proposed by Eric Drexler for assessing the capabilities of future technologies. He points out, for example, that the principles of space flight had been worked out long before science and industry advanced enough to get to actual launch.

 

For initial space flight development, the answers to the two questions above were dramatically different: what could be done in practice was far behind what had been established as theoretically possible, and there was no defined path between them. By identifying what was achievable according to physical law, the longer-term goal of space flight entered the consciousness of physicists, engineers, and politicians, bringing great minds and great resources to the challenge.

 

With the benefit of similarly future-focused knowledge, perhaps graphene might have received far more attention far sooner. Consider this: the groundbreaking experimental work that sparked the field as we know it today was the discovery that single-layer graphene could be extracted from a piece of graphite by (essentially) pressing cellophane tape against it and peeling it away. In other words, a decades-long roadblock to achievements in graphene research was not a matter of inadequate supporting technology but one of limited scientific attention.

 

Here graphene serves as a useful illustration of how progress could potentially be hindered when opportunity-based research is relied upon exclusively. Scientific advancement could benefit significantly from deliberate, exploratory engineering. Perhaps there are numerous other ‘graphenes’ right now, going unnoticed or under-prioritized, because we are failing to ask: what can be realized according to physical law?

 

English: Graphene layer. Français : Couche de ...

 

Quantum dots: The next big small thing


 

 

 

 

 

Quantum dots – tiny fluorescent crystals that contain just a few dozen molecules of semiconducting metal – are about to transition from an emerging technology to a mainstream product. The leading industrial producers of quantum dots have started delivering the first batches of their product to major electronics manufacturers in Asia, and the first quantum dot televisions and computer displays – which promise both enhanced colors and lower power use than regular LCD and LED-lit screens – are forecast to be on shop shelves within 18 months.

If their promise holds true, quantum dots could soon feature in everything from cell phone displays to digital cinema screens, and quantum dot lighting could soon outstrip even the latest energy-saving fluorescent bulbs and LEDs in terms of power efficiency and better colors.

And yet, quantum dots are still a technology in their infancy. Proponents say they could form the basis of new technologies, including flexible electronic displays, fluorescent textiles and wearable electronics, and even quantum-dot-based wall paints that can capture light and re-emit it into a room. And, if that is not enough, quantum dots might be about to revolutionize many optoelectronic technologies, such as imaging and light-gathering sensors, communications equipment, and solar power cells – including the possibility of a dramatic increase in the electricity produced from silicon solar panels – by enabling them to harvest more of the solar spectrum.

Medical researchers are also investigating the use of non-toxic quantum dots for medical imaging within the human body – potentially replacing some of the radioactive isotopes used in medical common scans. Future biomedical uses could include therapeutic doses of quantum dots that would deliver targeted control over malfunctioning cells within the body – such as cancer cells, brain neurons injured by a stroke, or damaged retinal cells.

Quantum dots could also be the key to entirely new optical technologies, including ultra-fast computers that use light instead of electricity for their logic, and photon-based quantum computers that could solve eldritch calculations beyond the ken of the largest modern supercomputers.

 

Quantum dots sound rather exotic, and indeed they are: each is a tiny semiconducting crystal, a few billionths of a meter across, typically consisting of about 50 or so atoms. As a sort of “small island” of semiconducting atoms, quantum dots have electronic and quantum mechanical properties somewhere between bulk semiconductors and individual molecules.

Quantum dots also have the industrial virtue of being easy to mass-produce – they can now be fabricated as rolled-out films, sprayed onto surfaces, and even manufactured by the bucketful, as fluorescent colloidal liquids. The dots can be made from a number of relatively abundant ingredients, including zinc, cadmium, selenium and sulfur – and even from materials with other special properties, such as graphene. One team of scientists recently described a new wet bulk method of producing high-quality graphene quantum dots, by treating ordinary carbon fiber with acetic acid – a chemical process akin to soaking charcoal in vinegar.

The key technological feature of quantum dots is that they are very fluorescent, and very bright. When a quantum dot is energized, by light or by an electric charge, it immediately re-emits the energy in a small burst of light at a very precise wavelength and color. Quantum dots have been likened to a tuning fork that always makes a particular note when struck – but when a quantum dot is “struck”, it produces a burst of light of a particular color.

The color of the light depends on the size of the dot and the material it is made from: large quantum dots emit red light, the smallest quantum dots emit blue light, and quantum dots of intermediate sizes can produce light in the rest of the spectrum. The colors are very bright, and can be tuned precisely when the quantum dots are made by controlling the proportions of raw ingredients and the temperature of the process, which limits the growth of the quantum dot crystals.

Quantum dots are significantly brighter than the phosphors used in most modern flat screens. They are highly efficient at absorbing light and re-emitting it in their signature color. And quantum dots are also chemically stable, and less prone to fade over time than conventional phosphors.

This makes quantum dots the prime contenders to replace the phosphors currently used in most displays. Some analysts speculate that the introduction of quantum dots in displays could affect demand for the rare earth elements (REEs) essential to many semiconducting display technologies, such as europium, terbium, and yttrium.

Recent shortages of such REEs have driven up production costs for flat screen displays, which have, in turn, driven manufacturers to look for new ways of making them. In 2008, phosphors for displays accounted for around 35 percent of the global demand for REEs – demand that could be expected to decline if quantum dots come into widespread use.

 

Quantum dots will arrive in our homes first as thinner flat-screen televisions with better colors, which are expected to reach the shops by the end of 2013.  The first designs are likely to integrate quantum dot technology into the existing production methods, improving the image quality by reproducing a greater range of colors than existing LCD screens.

A leading California-based nanotechnology company, Nanosys, is producing what it calls a “Quantum Dot Enhancement Film” for Korean electronics manufacturers LG and Samsung. The film is used as a phosphor in front of a blue LED backlight – light from the blue LED excites the quantum dots in the film, and they emit light in a range of colors that combine to form white light.

Blue LEDs are brighter and more energy efficient than white LEDS – and the quantum dot film produces white light that is better adjusted to human vision. Nanosys says the final image has a color range up to fifty percent greater than conventional LED screens, which are currently limited to about a third of the colors that the human eye can see. The Nanosys display uses about half the energy as a screen that uses white LEDs, which should help extend the battery life of mobile devices.

British nanotechnology firm Nanoco Group is also supplying electronics manufacturers in Japan, the USA, Korea and Taiwan with quantum dots for electronic displays. The company’s chief executive has said the first products containing Nanoco’s quantum dots will hit the market next year, and the company has already made two milestone deliveries of quantum dots to one of its customers in Japan. Nanoco has not revealed which companies it is working with, but Sony and Sharp are known to be working on quantum dot display technology.

Nanoco Group began ten years ago as a university spinout, with technology developed at the Manchester University and Imperial College London; it is now one of the leading nanotechnology companies in the UK, and listed on the London Stock Exchange AIM market in 2009.

The company says it is exploring a range of new uses for its quantum dots, including government-funded research into using them to find and kill cancer cells, an agreement with one of the world’s largest lighting companies to develop uses for quantum dots in general lighting, and a development deal with semiconductor firm Tokyo Electronto develop a more efficient type of solar panels using quantum dots.  Both Nanoco and Nanosys have plans to increase the efficiency of solar cells – by using a screen of quantum dots to “tweak” the incoming sunlight, so more light matches the wavelengths absorbed by the silicon solar cells.

Tetrapod Quantum Dots: The Future is Now


Mr Stephen Squires, CEO
Quantum Materials Corporation
United States
This presentation will be given at Printed Electronics USA 2012 on Dec 05, 2012.

Presentation Summary

A software controlled flow chemistry process for mass synthesis of high quantum yield inorganic Group II-VI Tetrapod Quantum Dots (TQD) is being developed that will scale to produce Kilogram quantities per day. These TQD are notable for their 90+% conversion for full tetrapod shape, equally high uniformity and selectivity of arm length and width (vital for electron transport). Tetrapod Quantum Dots are recognized as having superior characteristics among quantum dot shapes.
In addition, QMC has the exclusive worldwide license to quantum dot printing technologies developed by our CSO, Dr. Ghassan Jabbour, that have wide applications in R2R printed electronics and thin-film solar cell production.
We will discuss how the timeline for Quantum Dot applications is moving from the future to the present.

Speaker Biography (Stephen Squires)

Mr. Squires is the Chief Executive Officer for both Quantum Materials Corporation and it’s subsidiary, Solterra Renewable Technologies, Inc. He has over 25 years’ experience in advanced materials, nanotechnology and other emerging technologies. Prior to QMC/SRT, Stephen consulted on these fields with emphasis on applications engineering, strategic planning, commercialization and marketing.
From 1983 to 2001, Mr. Squires was Founder and CEO of Aviation Composite Technologies Inc., which he grew to have over 200 employees. ACT was merged with USDR Aerospace in 2001. He subsequently founded what is now Quantum Materials Corporation because of his lifelong interest in advanced materials, nanoparticles and Quantum Dots, with a vision to realize the potential of their unique quantum features.
Quantum Materials Corporations goal is to help Companies provide better technology at lower price points that are affordable in a mass marketplace. At the same time, he formed Solterra Renewable Technologies to create mass produced thin-film quantum dot solar cells using patented R2R printing technologies.

Quantum Materials Corp


QUANTUM MATERIALS CORPORATION has a steadfast vision that advanced technology is the solution to global issues related to cost, efficiency and increasing energy usage. Quantum dot semiconductors enable a new level of performance in a wide array of established consumer and industrial products, including low cost flexible solar cells, low power lighting and displays and biomedical research applications. Quantum Materials Corporation will invigorate these markets through cost reduction by replacing lab based experiments with volume manufacturing methods to establish a growing line of innovative high performance products.

*** Note to Readers. We at Trinity Alliance, LLP and GenesisNanoTech, have been following this company for over 3 years now. We are pleased to share their vision with all of you at this time. If you would like more information, please feel free to contact this author at:

bruceh.genesisnanotachnology@gmail.com       ***

Quantum Materials Corporation is a development stage nanotechnology and advanced materials company. We perceive an opportunity to acquire a significant amount of the nanomaterials market by commercializing a low cost high volume tetrapod quantum dot production process based on our exclusive license agreement with William Marsh Rice University and on additional proprietary processes and specialized knowledge that has been developed by the company and through our agreement with Access2Flow, a Netherlands based consortium focused on continuous flow chemistry. Our objective is to commercialize our high volume nanomaterials production processes and to use these materials to enable advanced and disruptive technologies that depend on a ready source of low cost materials in order for these technologies to become commercially viable.

SOLTERRA RENEWABLE TECHNOLOGIES, INC., a wholly owned subsidiary of QMC, is singularly positioned to lead the development of truly sustainable and cost-effective solar technology by introducing a new dimension of cost reduction by replacing silicon wafer-based solar cells with low-cost, highly efficient 3rd Generation, Quantum Dot-based solar cells.

Updates

SEC 10-K for year ending June 2012.  Here is the link: http://t.co/VhbnIEWz

Invited speaker at IdTechEx Printed Electronics USA 2012 . Our topic is “Quantum Dots: The Future is Now” The date is Dec. 5th at the Santa Clara Convention Center. If you will be attending either the conference or just the Trade Show, please let me know. Mr. Squires will be available for business related meetings.

Invited Speaker at the Emerging Molecular Diagnostics Partnering Forum on Feb 11-12 just prior to Molecular Medicine Tri-Conference Feb 12-13 (Moscone, SF) where we will for the first time be an Exhibitor. This is a tremendous opportunity because our quantum dots can fulfill so many needs in pharma and biomedicine. Mr. Squires topic is “Flow Chemistry Process Biocompatible Inorganic High Quantum Yield Tetrapod Quantum Dots For The Next Generation of Diagnostic Assays, Multiplexed Drug Delivery Platforms and POC Devices” Mr. Squires will again be available for business-related meetings.

QMC is in early stage discussions with a worldwide manufacturer/distributor/retailer of consumer goods concerning participation in the development of quantum dot consumer products that could result in two or more possible product collaborations for retail mass production and distribution. This would provide QMC and Solterra with an experienced partner in design, production, marketing and sale outlets for new consumer products. Further research and discussions are needed and industrial and commercial applications of these products could be developed independently of any alliance.

QMC has a NDA and is in discussions with a large molecular biology company currently successfully marketing recombinant proteins to researchers to functionalize QMC TQD to their own recombinant proteins, antibodies, aptamers, and peptides as value added product to sell to researchers in the life sciences. QMC is actively pursuing this same biotech market for other companies amenable to non-exclusive licensing of our quantum dots for research purposes or joint venture for development of advanced diagnostic tools delivering instant results at low cost or the use of our TQD as a drug delivery platform.

We are a public company traded OTC as QTMM

Specialties

Quantum Dots, R2R, Nanotechnology, Solar, Biomedical, Nanobio

Website: http://www.qmcdots.com

http://www.linkedin.com/company/1792886?trk=NUS_CMPY_TWIT