Making Solar Cells Obsolete with GIT’s Optical ‘Rectenna’ Technology ~ 40% to 90% Conversion Effciency: YouTube Video


Optical Rectenna download

Georgia Tech Professor of Mechanical Engineering, Dr. Bara Cola, shares how his childhood dreams of playing professional football turned into an exciting research career and important nanoengineering innovations. Dr. Cola’s breakthrough optical rectenna technology can be viewed here https://smartech.gatech.edu/handle/18….”

Watch the YouTube Video:

 

e9cf3-nanorectannaA new kind of nanoscale rectenna (half antenna and half rectifier) can convert solar and infrared into electricity, plus be tuned to nearly any other frequency as a detector.

Right now efficiency is only one percent, but professor Baratunde Cola and colleagues at the Georgia Institute of Technology (Georgia Tech, Atlanta) convincingly argue that they can achieve 40 percent broad spectrum efficiency (double that of silicon and more even than multi-junction gallium arsenide) at a one-tenth of the cost of conventional solar cells (and with an upper limit of 90 percent efficiency for single wavelength conversion).

It is well suited for mass production, according to Cola. It works by growing fields of carbon nanotubes vertically, the length of which roughly matches the wavelength of the energy source (one micron for solar), capping the carbon nanotubes with an insulating dielectric (aluminum oxide on the tethered end of the nanotube bundles), then growing a low-work function metal (calcium/aluminum) on the dielectric and voila–a rectenna with a two electron-volt potential that collects sunlight and converts it to direct current (DC).

“Our process uses three simple steps: grow a large array of nanotube bundles vertically; coat one end with dielectric; then deposit another layer of metal,” Cola told EE Times. “In effect we are using one end of the nanotube as a part of a super-fast metal-insulator-metal tunnel diode, making mass production potentially very inexpensive up to 10-times cheaper than crystalline silicon cells.”

Read the full Article Here: Solar Cells Will be Made Obsolete by 3D rectennas aiming at 40-to-90% efficiency

 

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Georgia Institute of Technology: New Low-Cost Technique Converts Bulk Alloys to Oxide Nanowires


git-nanowires-rd_1702_nanotech
Researchers have developed a new low-cost technique for converting bulk powders directly to oxide nanowires. Shown is a crucible in which an alloy of lithium and aluminum is being formed. Credit: Rob Felt, Georgia Tech

 

A simple technique for producing oxide nanowires directly from bulk materials could dramatically lower the cost of producing the one-dimensional (1D) nanostructures. That could open the door for a broad range of uses in lightweight structural composites, advanced sensors, electronic devices – and thermally-stable and strong battery membranes able to withstand temperatures of more than 1,000 degrees Celsius.

The technique uses a solvent reaction with a bimetallic alloy – in which one of the metals is reactive – to form bundles of nanowires (nanofibers) upon reactive metal dissolution. The process is conducted at ambient temperature and pressure without the use of catalysts, toxic chemicals or costly processes such as chemical vapor deposition. The produced nanowires can be used to improve the electrical, thermal and mechanical properties of functional materials and composites.

The research, which was reported this week in the journal Science, was supported by the National Science Foundation and California-based Sila Nanotechnologies. The process is believed to be the first to convert bulk powders to nanowires at ambient conditions.

“This technique could open the door for a range of synthesis opportunities to produce low-cost 1D nanomaterials in large quantities,” said Gleb Yushin, a professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “You can essentially put the bulk materials into a bucket, fill it with a suitable solvent and collect nanowires after a few hours, which is way simpler than how many of these structures are produced today.”

Yushin’s research team, which included former graduate students Danni Lei and James Benson, has produced oxide nanowires from lithium-magnesium and lithium-aluminum alloys using a variety of solvents, including simple alcohols. Production of nanowires from other materials is part of ongoing research that was not reported in the paper.

The dimensions of the nanowire structures can be controlled by varying the solvent and the processing conditions. The structures can be produced in diameters ranging from tens of nanometers up to microns.

“Minimization of the interfacial energy at the boundary of the chemical reaction front allows us to form small nuclei and then retain their diameter as the reaction proceeds, thus forming nanowires,” Yushin explained. “By controlling the volume changes, surface energy, reactivity and solubility of the reaction products, along with the temperature and pressure, we can tune conditions to produce nanowires of the dimensions we want.”

One of the attractive applications may be separator membranes for lithium-ion batteries, whose high power density has made them attractive for powering everything from consumer electronics to aircraft and motor vehicles. However, the polymer separation membranes used in these batteries cannot withstand the high temperatures generated by certain failure scenarios.

As result, commercial batteries may induce fires and explosions, if not designed very carefully and it’s extremely hard to avoid defects and errors consistently in tens of millions of devices.

Using low-cost paper-like membranes made of ceramic nanowires could help address those concerns because the structures are strong and thermally stable, while also being flexible – unlike many bulk ceramics. The material is also polar, meaning it would more thoroughly wetted by various battery electrolyte solutions.

“Overall, this is a better technology for batteries, but until now, ceramic nanowires have been too expensive to consider seriously,” Yushin said. “In the future, we can improve mechanical properties further and scale up synthesis, making the low-cost ceramic separator technology very attractive to battery designers.”

Fabrication of the nanowires begins with formation of alloys composed of one reactive and one non-reactive metal, such as lithium and aluminum (or magnesium and lithium). The alloy is then placed in a suitable solvent, which could include a range of alcohols, such as ethanol. The reactive metal (lithium) dissolves from the surface into the solvent, initially producing nuclei (nanoparticles) comprising aluminum.

Though bulk aluminum is not reactive with alcohol due to the formation of the passivation layer, the continuous dissolution of lithium prevents the passivation and allows gradual formation of aluminum alkoxide nanowires, which grow perpendicular to the surface of the particles starting from the nuclei until the particles are completely converted. The alkoxide nanowires can then be heated in open air to form aluminum oxide nanowires and may be formed into paper-like sheets.

The dissolved lithium can be recovered and reused. The dissolution process generates hydrogen gas, which could be captured and used to help fuel the heating step.

Though the process was studied first to make magnesium and aluminum oxide nanowires, Yushin believes it has a broad potential for making other materials. Future work will explore synthesis of new materials and their applications, and develop improved fundamental understanding of the process and predictive models to streamline experimental work.

The researchers have so far produced laboratory amounts of the nanowires, but Yushin believes that the process could be scaled up to produce industrial quantities. Though the ultimate cost will depend on many variables, he expects to see fabrication costs cut by several orders of magnitude over existing techniques.

“With this technique, you could potentially produce nanowires for a cost not much more than that of the raw materials,” he said. Beyond battery membranes, the nanowires could be useful in energy harvesting, catalyst supports, sensors, flexible electronic devices, lightweight structural composites, building materials, electrical and thermal insulation and cutting tools.

The new technique was discovered accidentally while Yushin’s students were attempting to create a new porous membrane material. Instead of the membrane they had hoped to fabricate, the process generated powders composed of elongated particles.

“Though the experiment didn’t produce what we were looking for, I wanted to see if we could learn something from it anyway,” said Yushin. Efforts to understand what had happened ultimately led to the new synthesis technique.

In addition to those already named, the research included Alexandre Magaskinski of Georgia Tech and Gene Berdichevsky of Sila Nanotechnologies.

Different aspects of this work were supported by NSF (grant 0954925) and Sila Nanotechnologies, Inc. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Gleb Yushin and Gene Berdichevsky are shareholders of Sila Nanotechnologies.

CITATION: Danni Lei, Jim Benson, Alexandre Magasinski, Gene Berdichevsky, Gleb Yushin, “Transformation of bulk alloys to oxide nanowires,” (Science, 2017).

Uniform ‘hairy’ nanorods have potential energy, biomedical applications


hairy-nanorods-123632_webIMAGE: IMAGE SHOWS MAGNETIC NANORODS IN THE VIAL ATTRACTED TO THE MAGNET. GEORGIA TECH RESEARCHERS HAVE DEVELOPED A NEW STRATEGY FOR CRAFTING ONE-DIMENSIONAL NANORODS BASED ON CELLULOSE USING A WIDE RANGE… view more

CREDIT: CREDIT: ROB FELT, GEORGIA TECH

 

GEORGIA INSTITUTE OF TECHNOLOGY

Materials scientists have developed a new strategy for crafting one-dimensional nanorods from a wide range of precursor materials. Based on a cellulose backbone, the system relies on the growth of block copolymer “arms” that help create a compartment to serve as a nanometer-scale chemical reactor. The outer blocks of the arms prevent aggregation of the nanorods.

The produced structures resemble tiny bottlebrushes with polymer “hairs” on the nanorod surface. The nanorods range in size from a few hundred nanometers to a few micrometers in length, and a few tens of nanometers in diameter. This new technique enables tight control over diameter, length and surface properties of the nanorods, whose optical, electrical, magnetic and catalytic properties depend on the precursor materials used and the dimensions of the nanorods.

The nanorods could have applications in such areas as electronics, sensory devices, energy conversion and storage, drug delivery, and cancer treatment. Using their technique, the researchers have so far fabricated uniform metallic, ferroelectric, upconversion, semiconducting and thermoelectric nanocrystals, as well as combinations thereof. The research, supported by Air Force Office of Scientific Research, will be reported on September 16 in the journal Science.

“We have developed a very general and robust strategy to craft a rich variety of nanorods with precisely-controlled dimensions, compositions, architectures and surface chemistries,” said Zhiqun Lin, a professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “To create these structures, we used nonlinear bottlebrush-like block copolymers as tiny reactors to template the growth of an exciting variety of inorganic nanorods.”

Nanorod structures aren’t new, but the technique used by Lin’s lab produces nanorods of uniform sizes – such as barium titanate and iron oxide, which have not yet been demonstrated via wet-chemistry approaches in the literature – and highly-uniform core-shell nanorods made by combining two dissimilar materials. Lin and former postdoctoral research associate Xinchang Pang say the precursor materials applicable to the technique are virtually limitless.

“There are many precursors of different materials available that can be used with this robust system,” Lin said. “By choosing a different outer block in the bottlebrush-like block copolymers, our nanorods can be dissolved and uniformly dispersed in organic solvents such as toluene or chloroform, or in water.”

Fabrication of the nanorods begins with the functionalization of individual lengths of cellulose, an inexpensive long-chain biopolymer harvested from trees. Each unit of cellulose has three hydroxyl groups, which are chemically modified with a bromine atom. The brominated cellulose then serves as macroinitiator for the growth of the block copolymer arms with well-controlled lengths using the atom transfer radical polymerization (ATRP) process, with, for example, poly(acrylic acid)-block-polystyrene (PAA-b-PS) yielding cellulose densely grafted with PAA-b-PS (i.e., cellulose-g-[PAA-b-PS]) that give the bottlebrush appearance.

The next step involves the preferential partitioning of precursors in the inner PAA compartment that serves as a nanoreactor to initiate the nucleation and growth of nanorods. The densely grafted block copolymer arms, together with the rigid cellulose backbone, give researchers the ability to not only prevent aggregation of the resulting nanorods, but also to keep them from bending.

“The polymers are like long spaghetti and they want to coil up,” Lin explained. “But they cannot do this in the complex macromolecules we make because with so many block copolymer arms formed, there is no space. This leads to the stretching of the arms, forming a very rigid structure.”

By varying the chemistry and the number of blocks in the arms of the bottlebrush-like block copolymers, Lin and coworkers produced an array of oil-soluble and water-soluble plain nanorods, core-shell nanorods, and hollow nanorods – nanotubes – of different dimensions and compositions.

For example, by using bottlebrush-like triblock copolymers containing densely grafted amphiphilic triblock copolymer arms, the core-shell nanorods can be formed from two different materials. In most cases, a large lattice mismatch between core and shell materials would prevent the formation of high-quality core-shell structures, but the technique overcomes that limitation.

“By using this approach, we can grow the core and shell materials independently in their respective nanoreactors,” Lin said. “This allows us to bypass the requirement for matching the crystal lattices and permits fabrication of a large variety of core-shell structures with different combinations that would otherwise be very challenging to obtain.”

Lin sees many potential applications for the nanorods.

“With a broad range of physical properties – optical, electrical, optoelectronic, catalytic, magnetic, and sensing – that are dependent sensitively on their size and shape as well as their assemblies, the produced nanorods are of both fundamental and practical interest,” Lin said. “Potential applications include optics, electronics, photonics, magnetic technologies, sensory materials and devices, lightweight structural materials, catalysis, drug delivery, and bio-nanotechnology.”

For example, plain gold nanorods of different lengths may allow effective plasmonic absorption in the near-infrared range for use in solar energy conversion with improved harvesting of solar spectrum. The upconversion nanorods can preferentially harvest the IR solar photons, followed by the absorption of emitted high-energy photons to generate extra photocurrent in solar cells. They can also be used for biological labeling because of their low toxicity, chemical stability, and intense luminescence when excited by near-IR radiation, which can penetrate tissue much better than higher energy radiation such as ultraviolet, as is often required with quantum dot labels.

The gold-iron oxide core-shell nanorods may be useful in cancer therapy, with MRI imaging enabled by the iron oxide shell, and local heating created by the photothermal effect on the gold nanorod core killing cancer cells.

In addition to the researchers already mentioned, co-authors included graduate research assistant Yanjie He and postdoctoral researcher Jaehan Jung in Georgia Tech’s School of Materials Science and Engineering.

This research was supported by the Air Force Office of Scientific Research under grant FA9550-16-1-0187. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsor.

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CITATION: Xinchang Pang, Yanjie He, Jaehan Jung, Zhiqun Lin, “1D nanocrystals with precisely controlled dimensions, compositions, and architectures,” (Science 2016).

Solar Cells Will be Made Obsolete by 3D rectennas aiming at 40-to-90% efficiency


Rectenna Naval Optical 150928122542_1_540x360A new kind of nanoscale rectenna (half antenna and half rectifier) can convert solar and infrared into electricity, plus be tuned to nearly any other frequency as a detector.

Right now efficiency is only one percent, but professor Baratunde Cola and colleagues at the Georgia Institute of Technology (Georgia Tech, Atlanta) convincingly argue that they can achieve 40 percent broad spectrum efficiency (double that of silicon and more even than multi-junction gallium arsenide) at a one-tenth of the cost of conventional solar cells (and with an upper limit of 90 percent efficiency for single wavelength conversion).

It is well suited for mass production, according to Cola. It works by growing fields of carbon nanotubes vertically, the length of which roughly matches the wavelength of the energy source (one micron for solar), capping the carbon nanotubes with an insulating dielectric (aluminum oxide on the tethered end of the nanotube bundles), then growing a low-work function metal (calcium/aluminum) on the dielectric and voila–a rectenna with a two electron-volt potential that collects sunlight and converts it to direct current (DC).

“Our process uses three simple steps: grow a large array of nanotube bundles vertically; coat one end with dielectric; then deposit another layer of metal,” Cola told EE Times. “In effect we are using one end of the nanotube as a part of a super-fast metal-insulator-metal tunnel diode, making mass production potentially very inexpensive up to 10-times cheaper than crystalline silicon cells.”

For commercialization, billions or even trillions of carbon-nanotube bundles could be grown side-by-side, ramping up the power output into the megaWatt range, after optimization for higher efficiency.

“We still have a lot of work to do to lower contact resistance which will improve the impedance match between the antenna and diode, thus raising efficiency,” Cola told us.”Our proof-of-concept was tuned to the near-infrared. We used infrared-, solar- and green laser-light and got efficiencies of less than one percent, but what was key to our demo was we showed our computer model matched our experimental results, giving us the confidence that we can improve the efficiency up to 40 percent in just a few years.”

For the future, Cola’s group has a three tiered goal–first develop sensor applications that don’t require high efficiencies, second to get the efficiency to 20 percent for harvesting waste heat in the infrared spectrum, then start replacing standard solar cells with 40 percent efficient panels in the visible spectrum. The team is also seeking suitable flexible substrates for applications that require bending.

 

Schematic of the components making up the optical rectenna–carbon nanotubes capped with a metal-oxide-metal tunneling diode. (Credit: Thomas Bougher)
(Source: Georgia Tech)

Nature Nanotechnology – A carbon nanotube optical rectenna

An optical rectenna—a device that directly converts free-propagating electromagnetic waves at optical frequencies to direct current—was first proposed over 40 years ago, yet this concept has not been demonstrated experimentally due to fabrication challenges at the nanoscale. Realizing an optical rectenna requires that an antenna be coupled to a diode that operates on the order of 1 pHz (switching speed on the order of 1 fs).

Diodes operating at these frequencies are feasible if their capacitance is on the order of a few attofarads but they remain extremely difficult to fabricate and to reliably couple to a nanoscale antenna. Here we demonstrate an optical rectenna by engineering metal–insulator–metal tunnel diodes, with a junction capacitance of ∼2 aF, at the tip of vertically aligned multiwalled carbon nanotubes (∼10 nm in diameter), which act as the antenna. Upon irradiation with visible and infrared light, we measure a d.c. open-circuit voltage and a short-circuit current that appear to be due to a rectification process (we account for a very small but quantifiable contribution from thermal effects). In contrast to recent reports of photodetection based on hot electron decay in a plasmonic nanoscale antenna a coherent optical antenna field appears to be rectified directly in our devices, consistent with rectenna theory. Finally, power rectification is observed under simulated solar illumination, and there is no detectable change in diode performance after numerous current–voltage scans between 5 and 77 °C, indicating a potential for robust operation.

 

GNT Thumbnail Alt 3 2015-page-001

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Georgia Institute of Technology: New Kind of ‘Smart-Glass Changes Color – Produces Electricity


Smart Glass 041015 5526909ae33ceA team of researchers working at the Georgia Institute of Technology has developed a type of smart-glass that not only changes color, but creates electricity. They have published a description of their work and the glass they have produced and some ideas on what the new kind of glass might be used for in their paper published in ACS Nano.

Many types of smart-glass have been created, some that display a tint when it gets sunny out, others that change to prevent heat from coming in, etc. In this new effort, the researchers sought to add something new—production of . Realizing that many types of glass are subjected to rain and wind, they sought to find a way to coat a window that would take advantage of triboelectrics—capturing the energy in that occurs when two materials meet.

They came up with a two layer solution, one layer to capture the energy in raindrops, the other to do the same for wind. In the first layer, the researchers developed nano-sized generators that would take advantage of the in raindrops that develops as it rubs against air on its way down from clouds and then as it crashes into a car’s windshield. The second layer consisted of a sandwich of two charged sheets of plastic with tiny springs between them. As wind pressure develops on an accelerating vehicle, the plastic sheets are pushed closer together, creating an .

Smart Glass 041015 5526909ae33ce

Together the two layers result in a glass that is initially clear, but then develops a blue tint—they also generated as much as 130 milliwatts of electricity per square meter of glass, which the researchers point out, is enough to charge a sleeping smartphone. Moving forward, the team suggests that such types of glass could be used with wireless networks because it is not based on a separate power source. But, before that can happen, the team is looking into ways to store the power that is generated. They think it might be possible to embed see-through super-capacitors in the glass as well. At this time, it is not clear how much with all that embedded technology would cost.

Explore further: Researchers invent smart window that tints and powers itself

More information: Motion-Driven Electrochromic Reactions for Self-Powered Smart Window System, ACS Nano, Article ASAP. DOI: 10.1021/acsnano.5b00706

Abstract
The self-powered system is a promising concept for wireless networks due to its independent and sustainable operations without an external power source. To realize this idea, the triboelectric nanogenerator (TENG) was recently invented, which can effectively convert ambient mechanical energy into electricity to power up portable electronics.

In this work, a self-powered smart window system was realized through integrating an electrochromic device (ECD) with a transparent TENG driven by blowing wind and raindrops. Driven by the sustainable output of the TENG, the optical properties, especially the transmittance of the ECD, display reversible variations due to electrochemical redox reactions.

The maximum transmittance change at 695 nm can be reached up to 32.4%, which is comparable to that operated by a conventional electrochemical potentiostat (32.6%). This research is a substantial advancement toward the practical application of nanogenerators and self-powered systems.

Polymer Structures Serve as ‘Nanoreactors’ for Nanocrystals


QDOTS imagesCAKXSY1K 8Using star-shaped block co-polymer structures as tiny reaction vessels, researchers have developed an improved technique for producing nanocrystals with consistent sizes, compositions and architectures – including metallic, ferroelectric, magnetic, semiconductor and luminescent nanocrystals. The technique relies on the length of polymer molecules and the ratio of two solvents to control the size and uniformity of colloidal nanocrystals.

 

The technique could facilitate the use of nanoparticles for optical, electrical, optoelectronic, magnetic, catalysis and other applications in which tight control over size and structure is essential to obtaining desirable properties. The technique produces plain, core-shell and hollow nanoparticles that can be made soluble either in water or in organic solvents.

“We have developed a general strategy for making a large variety of nanoparticles in different size ranges, compositions and architectures,” said Zhiqun Lin, an associate professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “This very robust technique allows us to craft a wide range of nanoparticles that cannot be easily produced with any other approaches.”

The technique was described in the June issue of the journal Nature Nanotechnology. The research was supported by the Air Force Office of Scientific Research.

Georgia Tech professor Zhiqun Lin examines a gold nanoparticle toluene solution. The work is part of research on using star-shaped block co-polymers to create nanocrystals of uniform size and shape.

(Photo Credit:  Georgia Tech Photo: Gary Meek)

The star-shaped block co-polymer structures consist of a central beta-cyclodextrin core to which multiple “arms” – as many as 21 linear block co-polymers – are covalently bonded. The star-shaped block co-polymers form the unimolecular micelles that serve as a reaction vessel and template for the formation of the nanocrystals.

The inner blocks of unimolecular micelles are poly(acrylic) acid (PAA), which is hydrophilic, which allows metal ions to enter them. Once inside the tiny reaction vessels made of PAA, the ions react with the PAA to form nanocrystals, which range in size from a few nanometers up to a few tens of nanometers. The size of the nanoparticles is determined by the length of the PAA chain.

The block co-polymer structures can be made with hydrophilic inner blocks and hydrophobic outer blocks – amphiphilic block co-polymers, with which the resulting nanoparticles can be dissolved in organic solvents. However, if both inner and outer blocks are hydrophilic – all hydrophilic block co-polymers – the resulting nanoparticles will be water-soluble, making them suitable for biomedical applications.

Lin and collaborators Xinchang Pang, Lei Zhao, Wei Han and Xukai Xin found that they could control the uniformity of the nanoparticles by varying the volume ratio of two solvents – dimethlformamide and benzyl alcohol – in which the nanoparticles are formed. For ferroelectric lead titanate (PbTiO3) nanoparticles, for instance, a 9-to-1 solvent ratio produces the most uniform nanoparticles.

The researchers have also made iron oxide, zinc oxide, titanium oxide, cuprous oxide, cadmium selenide, barium titanate, gold, platinum and silver nanocrystals. The technique could be applicable to nearly all transition or main-group metal ions and organometallic ions, Lin said.

“The crystallinity of the nanoparticles we are able to create is the key to a lot of applications,” he added. “We need to make them with good crystalline structures so they will exhibit good physical properties.”

Earlier techniques for producing polymeric micelles with linear block co-polymers have been limited by the stability of the structures and by the consistency of the nanocrystals they produce, Lin said. Current fabrication techniques include organic solution-phase synthesis, thermolysis of organometallic precursors, sol-gel processes, hydrothermal reactions and biomimetic or dendrimer templating. These existing techniques often require stringent conditions, are difficult to generalize, include a complex series of steps, and can’t withstand changes in the environment around them.

Georgia Tech professor Zhiqun Lin (standing) watches research scientist Xinchang Pang tuning the experimental condition in the nanocrystal synthesis.

(Photo Credit:  Georgia Tech Photo: Gary Meek)

By contrast, nanoparticle production technique developed by the Georgia Tech researchers is general and robust. The nanoparticles remain stable and homogeneous for long periods of time – as much as two years so far – with no precipitation. Such flexibility and stability could allow a range of practical applications, Lin said.

“Our star-like block co-polymers can overcome the thermodynamic instabilities of conventional linear block co-polymers,” he said. “The chain length of the inner PAA blocks dictates the size of the nanoparticles, and the uniformity of the nanoparticles is influenced by the solvents used in the system.”

The researchers have used a variety of star-like di-block and tri-block co-polymers as nanoreactors. Among them are poly(acrylic acid)-block-polystyrene (PAA-b-PS) and poly(acrylic acid)-blockpoly(ethylene oxide) (PAA-b-PEO) diblock co-polymers, and poly(4-vinylpyridine)-block-poly(tert-butyl acrylate)-block-polystyrene (P4VP-b-PtBA-b-PS), poly(4-vinylpyridine)-block-poly (tert-butyl acrylate)-block-poly(ethylene oxide) (P4VP-b-PtBA-b-PEO), polystyrene-block-poly(acrylic acid)-block-polystyrene (PS-b-PAA-b-PS) and polystyrene-block-poly(acrylic acid)-block-poly(ethylene oxide) (PS-b-PAA-b-PEO) tri-block co-polymers.

For the future, Lin envisions more complex nanocrystals with multifunctional shells and additional shapes, including nanorods and so-called “Janus” nanoparticles that are composed of biphasic geometry of two dissimilar materials.

Georgia Tech professor Zhiqun Lin (standing) and research scientist Xinchang Pang compare two cadmium selenide (CdSe) nanocrystals made by Pang. The researchers are examining the absorption spectra of the nanocrystals in front of the computer.

(Photo Credit:  Georgia Tech Photo: Gary Meek)

9 Incredible Uses for Graphene


QDOTS imagesCAKXSY1K 8Graphene is amazing. Or at least, it could be. Made from a layer of carbon one-atom thick, it’s the strongest material in the world, it’s completely flexible, and it’s more conductive than copper. Discovered just under a decade ago, the supermaterial potentially has some unbelievable applications for us in the not so distant future. All of these are just hypothetical at this point, but could be real before we know it.

And they’re all flippin incredible!

Water, water everywhere and EVERY drop drinkable. MIT minds have a plan for a graphene filter covered in tiny holes just big enough to let water through and small enough to keep salt out, making salt water safe for consumption.

Potable Water

Mega-fast uploads. We’re talking a whole terabit in just one second.

Mega Uploads

Plug your phone in for five seconds and it would be all charged up. The downside here is that you won’t be able to use a dead phone as an excuse anymore.

1200-mediabridge-portable-surge-protector

What if we actually had a clear solution for cleaning up the tainted water near Fukushima? Scientists at Rice say graphene could potentially clump together radioactive waste, making disposal is a breeze.

Fukijima

Graphene could pave the way for bionic devices in living tissues that could be connected directly to your neurons. So people with spinal injuries, for example, could re-learn how to use their limbs.

Human Body

It could improve your tennis game, thanks to special racquets from HEAD that aim to put the weight where it’s more useful: in the head and the grip.

Tennis Racket

Touchscreens that use graphene as their conductor could be slapped onto plastic rather than glass. That would mean super thin, unbreakable touchscreens and never worrying about shattering your phone ever again.

Phone Glass

High-power graphene supercapacitors would make batteries obselete.

supercapacitors

Just a single sheet of graphene could produce headphones that have a frequency response comparable to a pair of Sennheisers, as some scientists at UC Berkeley recently showed us.

Berkley Frequency

ARAPA-E Backs 66 New Projects


The Department of Energy’s high-risk early stage grant program, ARPA-E, has announced 66 new energy-related projects that will get small amounts of funding and mentorship from the DOE. ARPA-E said that it will give 66 groups — from universities, to startups, to government labs to large companies — a combined $130 million through its Open 2012 program to help them with cutting edge innovation around cleaner and more efficient transportation as well as energy generation and consumption.

The ARPA-E program is one of the DOE’s lauded programs, which has managed to gain bipartisan support and avoid controversy. In contrast, the DOE’s loan guarantee program and battery grant programs allocated large funds to single companies, and when a few of those companies went bankrupt, the DOE received significant criticism.

The ARPA-E program, on the other hand, only gives grants of small — hundreds of thousands to single digit millions — amounts and doesn’t expect to get a return back. It’s funding for basic scientific research. The program also backs so-called “moonshots,” which are innovations that could be transformational, but are at a very early stage — a very small amount of these technologies will probably ever be commercialized. The folks at ARPA-E now say they’ve backed 285 projects for a total of about $770 million in funding.

There were fewer startups in the mix than I’ve seen in recent years. It’s a lot harder to be an entrepreneur in this space these days. Some of the more interesting sounding projects in this crop include:

  • Energy beets: Say wha? A company called Plant Sensory Systems, has received a $1.8 million grant to engineer a beet with enhanced energy density that can be turned into biofuels, and which can also be grown with less water and fertilizer.
  • Waste natural gas to fuel: A company called Ceramatec was granted $1.7 million to build a reactor that can convert natural gas unearthed at remote oil field sites into fuel in one step. This natural gas is usually flared off and wasted.
  • Smart window coatings: Lawrence Berkeley National Labs will use a $3 million grant to low cost coatings for windows that will control light and heat.
  • Portable building mapping tech: LBNL received another grant, this one for $1.9 million, to make a device that senses and maps the internal and thermal characteristics for a building. Using this technology, you can see where heat loss is occurring. Sounds like Essess.
  • Cool roofs: Stanford University is looking to develop a low cost coating for roofs, buildings and cars that reflects sunlight and enables passive cooling. ARPA-E gave Stanford $400,000 to build the tech.
  • Smart grid security modelling: The University of Illinois at Urbana-Champaign received a $1.5 million grant to create a modelling and analysis tools to make the smart grid more secure.
  • Gas-based tech for high voltage power lines: The traditional way to control electricity over high voltage transmission lines is using silicon-based switches. GE’s Global Research division received a $4.1 million grant to work on a gas-based switch that can lower the cost of transmission lines, improve grid reliability, and help with clean power deployment.
  • Super wires: A startup called Grid Logic is working on low cost and high temperature superconducting wires. ARPA-E gave the company a $3.8 million grant.
  • Transmission line analytics: Pacific Northwest National Labs received a $1.6 million grant to develop analytics to find unused space on transmission lines and increase efficiency of the use of transmission lines by 30 percent.
  • Big data grid collection: The University of California, Berkeley, along with the California Institute for Energy and Environment, have received $4 million to develop “micro” synchrophasors to collect real time grid data. Are these even smaller versions of the synchrophasors out there? Not sure, I’ll do some research on it.
  • Water wing: Brown University will work on an “oscillating underwater wing” that can capture energy from flowing water in rivers and tides. They’ll control it with software. I feel like a lot of companies who make these design really nice ones, but the problem is in making sure it lasts years while being battered by water and the elements. Brown received $750,000 for this project.
  • Fabric wind blades: GE has quite a few projects in here. Another one is a project to create wind blades made out of fabric stretched across a frame. GE says such blades could enable wind turbines to be “manufactured in sections and assembled on-site, enabling the construction of much larger wind turbines with higher efficiency and lower cost.”
  • Energy from dust devils: Here’s a weird one (for @go2cleanbreak’s book). The Georgia Institute for Technology wants to use a $3.7 million grant to capture energy from wind vortices by harvesting a thin layer of hot air along the ground created by the sun. Like a manufactured, controlled dust devil. I don’t know what to say about that one.
  • Mini mirror solar field: San Francisco’s own Otherlab is working on developing solar projects with small mirrors that will focus light onto towers. Usually these types of fields (like Ivanpah) use large mirrors.
  • New Valley battery startup?: A startup called Alveo Energy won a $4 million grant for a battery for grid storage that will use Prussian Blue dye as the active material in the battery. They were founded in 2012, based in Palo Alto and their CEO is Colin Wessells, according to Google searches (they don’t have a website). If anyone knows more about this company, ping me.
  • Magnetic energy storage: Here’s a new one. The Tai Yang Research Company wants to create a device that stores energy in superconducting cables, by increasing magnetic field strength of the cable.
  • Solar fuel: The Georgia Institute of Technology received $3.6 million to build a solar reactor to produce solar fuel. Sounds like what Joule has been working on … by the way, whatever happened to them?
  • Printed batteries: The Palo Alto Research Center got close to a million dollars to develop printing technology for lithium ion batteries

Image courtesy of Peyri, and rosmary.