Category Archives: energy

Gold nanorod instabilities

A Dec. 8, 2014 news item on Nanowerk focuses on research from Australia,

Researchers at Swinburne University of Technology [Melbourne, Australia]  have discovered an instability in gold nanoparticles that is critical for their application in future technology.

Gold nanorods are important building blocks for future applications in solar cells, cancer therapy and optical circuitry.

However their stability is under question due to their peculiar reshaping behaviour below melting points.

A Dec. 8, 2014 Swinburne University of Technology press release, which originated the news item, discusses melting points and shape instabilities in the context of this research,

A solid normally does not change its shape unless it reaches its melting point, or surface melting points. It is also known that the melting point for nanoparticles is suppressed due to their size.

PhD student Adam Taylor (now a postdoctoral researcher at Swinburne) said it came as a surprise that reshaping is observed well below these melting points. Until now, no one could explain this peculiar behaviour.

“In our work, we have discovered both theoretically and experimentally that the reshaping mechanism for nanoparticles below melting point is surface atom diffusion, rather than melting,” Mr Taylor said.

Surface atom diffusion is a process involving the motion of molecules at solid material surfaces that can generally be thought of in terms of particles jumping between adjacent adsorption sites on a surface.

“Surface atom diffusion always existed in bulk solids, but this is the first evidence that its effect is enhanced at the nano-size, dominating over the traditional theory of melting,” Associate Professor James Chon, who is supervising Mr Taylor’s research, said.

Mr Taylor said the more finely nanoparticles are shaped, the less stable they become.

“This is important, for example, for solar panel manufacturers as the more needle-like these nanoparticles are shaped the less stable they become. If you put these particles into a solar panel to concentrate light they may not last long in the sun before they degrade,” Mr Taylor said.

“This discovery will be crucial for future applications of gold nanorods, as people will need to reconsider their stability when applying them to solar cells, cancer therapeutic agents and optical circuitry.”

The researchers have provided an illustration of their work,

Courtesy Swinburne University of Technology

Courtesy Swinburne University of Technology

Here’s a link to and citation for the research,

Below Melting Point Photothermal Reshaping of Single Gold Nanorods Driven by Surface Diffusion by Adam B. Taylor, Arif M. Siddiquee, and James W. M. Chon. ACS Nano, Article ASAP DOI: 10.1021/nn5055283 Publication Date (Web): November 18, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall but should you be in Australia and eligible to attend, there’s another opportunity to learn more; Taylor will be presenting his work at the Australian Institute of Physics conference on December 10, 2014 in Canberra.

Spray-on solar cells from the University of Toronto (Canada)

It’s been a while since there’s been a solar cell story from the University of Toronto (U of T) and I was starting to wonder if Ted (Edward) Sargent had moved to another educational institution. The drought has ended with the announcement of three research papers being published by researchers from Sargent’s U of T laboratory. From a Dec. 5, 2014 ScienceDaily news item,

Pretty soon, powering your tablet could be as simple as wrapping it in cling wrap.

That’s Illan Kramer’s … hope. Kramer and colleagues have just invented a new way to spray solar cells onto flexible surfaces using miniscule light-sensitive materials known as colloidal quantum dots (CQDs) — a major step toward making spray-on solar cells easy and cheap to manufacture.

A Dec. 4, 2014 University of Toronto news release (also on EurekAlert) by Marit Mitchell, which originated the news item, gives a bit more detail about the technology (Note: Links have been removed),

 Solar-sensitive CQDs printed onto a flexible film could be used to coat all kinds of weirdly-shaped surfaces, from patio furniture to an airplane’s wing. A surface the size of a car roof wrapped with CQD-coated film would produce enough energy to power three 100-watt light bulbs – or 24 compact fluorescents.

He calls his system sprayLD, a play on the manufacturing process called ALD, short for atomic layer deposition, in which materials are laid down on a surface one atom-thickness at a time.

Until now, it was only possible to incorporate light-sensitive CQDs onto surfaces through batch processing – an inefficient, slow and expensive assembly-line approach to chemical coating. SprayLD blasts a liquid containing CQDs directly onto flexible surfaces, such as film or plastic, like printing a newspaper by applying ink onto a roll of paper. This roll-to-roll coating method makes incorporating solar cells into existing manufacturing processes much simpler. In two recent papers in the journals Advanced Materials and Applied Physics Letters, Kramer showed that the sprayLD method can be used on flexible materials without any major loss in solar-cell efficiency.

Kramer built his sprayLD device using parts that are readily available and rather affordable – he sourced a spray nozzle used in steel mills to cool steel with a fine mist of water, and a few regular air brushes from an art store.

“This is something you can build in a Junkyard Wars fashion, which is basically how we did it,” says Kramer. “We think of this as a no-compromise solution for shifting from batch processing to roll-to-roll.”

“As quantum dot solar technology advances rapidly in performance, it’s important to determine how to scale them and make this new class of solar technologies manufacturable,” said Professor Ted Sargent, vice-dean, research in the Faculty of Applied Science & Engineering at University of Toronto and Kramer’s supervisor. “We were thrilled when this attractively-manufacturable spray-coating process also led to superior performance devices showing improved control and purity.”

In a third paper in the journal ACS Nano, Kramer and his colleagues used IBM’s BlueGeneQ supercomputer to model how and why the sprayed CQDs perform just as well as – and in some cases better than – their batch-processed counterparts. This work was supported by the IBM Canada Research and Development Centre, and by King Abdullah University of Science and Technology.

For those who would like to see the sprayLD device,

Here are links and citation for all three papers,

Efficient Spray-Coated Colloidal Quantum Dot Solar Cells by Illan J. Kramer, James C. Minor, Gabriel Moreno-Bautista, Lisa Rollny, Pongsakorn Kanjanaboos, Damir Kopilovic, Susanna M. Thon, Graham H. Carey, Kang Wei Chou, David Zhitomirsky, Aram Amassian, and Edward H. Sargent. Advanced Materials DOI: 10.1002/adma.201403281 Article first published online: 10 NOV 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Colloidal quantum dot solar cells on curved and flexible substrates by Illan J. Kramer, Gabriel Moreno-Bautista, James C. Minor, Damir Kopilovic, and Edward H. Sargent. Appl. Phys. Lett. 105, 163902 (2014); http://dx.doi.org/10.1063/1.4898635 Published online 21 October 2014

© 2014 AIP Publishing LLC

Electronically Active Impurities in Colloidal Quantum Dot Solids by Graham H. Carey, Illan J. Kramer, Pongsakorn Kanjanaboos, Gabriel Moreno-Bautista, Oleksandr Voznyy, Lisa Rollny, Joel A. Tang, Sjoerd Hoogland, and Edward H. Sargent. ACS Nano, 2014, 8 (11), pp 11763–11769 DOI: 10.1021/nn505343e Publication Date (Web): November 6, 2014

Copyright © 2014 American Chemical Society

All three papers are behind paywalls.

Given the publication dates for the papers, this looks like an attempt to get some previously announced research noticed by sending out a summary news release using a new ‘hook’ to get attention. I hope it works for them as it must be disheartening to have your research sink into obscurity because the announcements were issued during one or more busy news cycles.

One final note, if I understand the news release correctly, this work is still largely theoretical as there don’t seem to have been any field tests.

Peter Sircom Bromley’s documentary: No Carbon Nation released December 2014

I don’t usually include information of this type, a documentary about policy, energy, and sustainability (in other words, no nano, no research focus, no art) on my blog. However, one good turn deserves another. and Peter Bromely offered me a good turn a few years ago.

Here’s the text of the Dec. 1, 2014, news release sent out in support of No Carbon Nation,

The conceptual framework for climate action is straightforward and applies to all jurisdictions around the world. However, in order to coordinate effective action, and gain political support for it, it’s important that people everywhere be clear on that framework. This is one of the main ideas behind No Carbon Nation: pathways to sustainable energy, an independent documentary released on the internet today.

No Carbon Nation focuses on energy transition, which is the centerpiece of climate policy in progressive jurisdictions worldwide. Beginning with an introductory overview of climate diplomacy as organized by the Kyoto Protocol, the documentary offers the viewer a basic understanding of the energy sector and summarizes the technological and regulatory tools available to make the required changes to it. No Carbon Nation also identifies institutional behavior as a major barrier to change. “Individuals and institutions tend to rely heavily on what they’ve done before. There is no reward for making the effort to change,” says the filmmaker, Peter Sircom Bromley, based in Vancouver, Canada. “The world has all the technical and regulatory tools it needs to avoid dangerous climate change. We just need to collectively bite the bullet.”

As a documentary, No Carbon Nation is a distilled, tightly edited, relentless, and sometimes lyrical compilation of what progressive jurisdictions and industries worldwide are doing – and not doing – to reduce human impacts on the climate. It is punctuated by interviews with professionals on the front lines of energy transition, including management personnel at the Los Angeles Department of Water and Power (LADWP), the largest municipal utility in the US. The LADWP operates in a jurisdiction with some of the most ambitious greenhouse gas emission reduction policies in the world.

The demand side of energy

Fossil fuel producers get scant attention in the film. “Oil, gas and coal suppliers are simply feeding the world’s energy systems. So stopping fossil fuel combustion, the main contributor to climate change, means changing those systems. In other words, we need to deal with the demand side,” says the filmmaker, a former Sierra Club director who has been engaged with climate policy since 1995. “And that means transforming energy systems across all sectors of the world economy: electricity generation, transportation, buildings and heavy industry.”

The film is “sort of like dots on a map, identifying pressure points where action is more effective and actually taking place. In that sense it’s not complicated,” says Bromley. “Call it a feature length public service announcement. Hopefully viewers who manage to sit through it will find the film a useful primer for climate action – be it buying an electric vehicle, giving clear directives to their government representatives, or switching off a light.”

Internet provides significant content

Almost half the footage used in the documentary came from diverse online sources including the US Department of Energy, the European Commission, and The Newsmarket, as did eight of 24 interviews and sound bites. “Lots of people are making excellent material on the topic available. Why duplicate their efforts?” Bromley says, adding that the project was largely a writing and editing challenge. “The main thing was to make a highly complex and diverse set of issues easy to understand – both for the viewer, and for myself,” he chuckles. “It’s like McLuhan said: give people too much information and they instantly resort to pattern recognition.”

The documentary, in 720 HD, is free to watch online (www.NoCarbonNation.net) as a complete film, or in four parts for those who prefer to pace themselves through the full 94 minutes. A website is built around the documentary, and provides viewers with links to explore the subject in greater detail. However, a more leisurely viewing experience can be had with a large screen and a good sound system. The documentary and website will be updated from time to time. “Things are changing pretty fast,” says the filmmaker.

contact: Peter Sircom Bromley

[email protected]

From what I’ve seen of part one, this is a deeply felt and intense piece of filmmaking dedicated to a topic, energy policy, that would seem highly unsuited to this treatment. Bravo to Peter Sircom Bromley for finding a way to make it cinematic and accessible!

Canadian nano: Lomiko Metals and its graphene supercapacitor project and NanoTech Security at a TEDx in Vancouver (Canada)

As best I can determine Lomiko Metals is involved in a graphene-based supercapacitor project with at least two interlocking pieces. Piece one is described in an Oct. 28, 2014 news item on Azonano,

Lomiko Metals Inc. and its 100% owned subsidiary Lomiko Technologies Inc. are pleased to announce an agreement to license from Megahertz Power Systems Ltd. rights to manufacture and sell three (3) power converter system designs, acquire a pending supply contract with a Canadian LED system integrator and support the research and development of new products.

“The Power Converter Market is a multi-billion dollar market. With the increasing demand for energy-efficient electronic devices, the advent of re-chargeable batteries and the new market for quick-charge supercapacitors, Lomiko has the opportunity to move into a growing market with a profitable business model.”, stated A. Paul Gill, CEO. [emphasis mine]

Lomiko will establish cash-flow under the current Customer Contract within six months which is based on proven and in-demand devices designed by MegaHertz. The creation of an e-commerce site in three to four (3-4) months will increase the customer base for the Licensed Power Systems over the estimated five (5) year product cycle. In the long term, Lomiko and MegaHertz will work on innovative new designs that power products using graphite and graphene based devices to dramatically raise operating efficiencies and help reduce the energy waste for the Electronic equipment, Energy Storage and Automotive Industries worldwide. [emphasis mine]

You can read more about the details in the Azonano news item or in the Lomiko Metals Oct. 27, 2014 news release.

As for piece two, Lomiko Metals has announced a supecapacitor project which would seem to align with the objectives mentioned in the October 2014 MegaHertz deal “… Lomiko and MegaHertz will work on innovative new designs that power products using graphite and graphene based devices to dramatically raise operating efficiencies and help reduce the energy waste … .” From a Dec. 4, 2014 news item on Azonano,

Lomiko Metals Inc. is very pleased to announce it has signed an agreement to invest in a new graphene-related venture, Graphene Energy Storage Devices (Graphene ESD Corp.), a U.S. Corporation.

On December 4, 2013, Lomiko reported on a successful conclusion to Phase I of its Graphene Supercapacitor Project which involved Graphene Laboratories Inc. and Stony Brook University. Graphene ESD Corp. has been formed to commercialize the technology and bring the graphene-based energy storage devices to market.

Supercapacitors bridge the gap between conventional capacitors and rechargeable batteries. They store the most energy per unit volume or mass (energy density) among capacitors. Supercapacitors power density is generally 10 to 100 times greater than normal capacitors or batteries. This results in much shorter charge/discharge cycles than batteries. Additionally, they will tolerate many more charge and discharge cycles than batteries. Incorporation of graphene material in supercapacitor electrodes may further improve energy and power density of the device. Graphene ESD Corp. will develop low-cost graphene-based supercapacitor devices that will be capable of even higher discharge currents. The development will focus on large-scale devices that are projected to have the lowest cost of power and stored energy in its class.

“As reported December 4, 2013, the Phase I Graphene Supercapacitor project yielded encouraging results. Graphene ESD Corp. will build on the success of this project and will be developing a graphene-based supercapacitor. [emphasis mine] The device is designed as a versatile energy storage solution for electronics, electric vehicles and electric grid.” stated A. Paul Gill, CEO of Lomiko Metals Inc. [emphasis mine] Graphene is finding new application in sensors, electronics, and advanced materials. Energy storage is a rapidly developing field which can benefit from the outstanding properties of graphene. We believe that graphene-based devices will deliver the best value for multiple energy storage applications.”

You can find more details both in the Azonano news item and in the Lomiko Metals Dec. 3, 2014 news release.

The second half of this post’s headline concerns a talk by Clint Landrock, Executive Vice President of Products for NanoTech Security Corp. and more, at the Renfrew-Collingwood (a neighbourhood in Vancouver, Canada) TEDx. From an Oct. 29, 2014 news item on Azonano,

Nanotech Security Corp. today announced that Vice President Clint Landrock presented at TEDxRenfrewCollingwood. The independently organized TED event was held on October 24, 2014.

The day-long event brought together more than 400 creators, catalysis, designers and thinkers from the Vancouver area to share ideas around the theme “Rock, Paper, Scissors.” Landrock presented on the influence of nature on innovation in technology, using Nanotech’s story as one example of what can be achieved when companies turn to nature as a source of inspiration. …

Landrock’s talk (a little over 11 mins. running time) has now been posted on YouTube or you can find it here. The organizers have posted this description of Landrock,

Clint serves as the Executive Vice President of Products for NanoTech Security Corp., and is a co-founder of IDME Technologies Corp.  He is an expert in the study of nano-optics and biomimicry. Clint currently holds several patents and over a dozen peer-reviewed publications in the field. He completed his bachelor degree in aerospace engineering at Ryerson Polytechnic University in Toronto, and his Masters of Applied Sciences at Simon Fraser University. Clint’s interests include commercial applications of nanotechnology and smart polymers, biomimicry, alpine and rock climbing and generally being outside.

I haven’t watched the talk in its entirety but he starts with the wonder and the dark side of technology. As his company, NanoTech Security, is a spin-off from Simon Fraser University and the technology is based on the nanostructures found on the Blue Morpho butterfly’s wing, I imagine the rest of his talk consists of biomimcry and ways of imitating nature as a means of dealing with the damaging aspects resulting from some of our current technologies.

India, Lockheed Martin, and canal-top solar power plants

Apparently the state of Gujarat (India) has inspired at least one other state, Punjab, to build (they hope) a network of photovoltaic (solar energy) plants over top of their canal system (from a Nov. 16, 2014 article by Mridul Chadha for cleantechnica.com),

India’s northern state of Punjab plans to set up 1,000 MW of solar PV projects to cover several kilometres of canals over the next three years. The state government has announced a target to cover 5,000 km of canals across the state. Through this program, the government hopes to generate 15% of the state’s total electricity demand.

Understandably, the construction of canal-top power plants is technically and structurally very different from rooftop or ground-based solar PV projects. The mounting structures for the solar PV modules cannot be heavy, as it could adversely impact the structural integrity of the canal itself. The structures should be easy to work with, as they are to be set up over a slope.

This is where the Punjab government has asked Lockheed Martin for help. The US-based company has entered into an agreement with the Punjab government to develop lightweight mounting structures for solar panels using nanotechnology.

Canal and rooftop solar power projects are the only viable options for Punjab as it is an agricultural state and land availability for large-scale ground-mounted projects remains an issue. As a result, the state government has a relatively lower (compared to other states) capacity addition target of 2 GW.

There’s more about the Punjab and current plans to increase its investment in solar photovoltaics in the article.

Here’s an image of a canal-top solar plant near Kadi (Gujarat),

Canal_Top_Solar_Power_PlantImage Credit: Hitesh vip | CC BY-SA 3.0

A Nov. 15, 2014 news item by Kamya Kandhar for efytimes.com provides a few more details about this Memorandum of Understanding (MOU),

Punjab government had announced its tie up with U.S. aerospace giant Lockheed Martin to expand the solar power generation and overcome power problems in the State. As per the agreement, the state will put in 1,000 MW solar power within the next three years. Lockheed Martin has agreed to provide plastic structures for solar panels on canals by using nano technology.

While commenting upon the agreement, a spokesperson said, “The company would also provide state-of-the-art technology to convert paddy straw into energy, solving the lingering problem of paddy straw burning in the state. The Punjab government and Lockheed Martin would ink a MoU in this regard [on Friday, Nov. 14, 2014].”

The decision was taken during a meeting between three-member team from Lockheed Martin, involving the CEO Phil Shaw, Chief Innovation Officer Tushar Shah and Regional Director Jagmohan Singh along with Punjab Non-Conventional Energy Minister Bikram Singh Majithia and other senior Punjab officials.

As for paddy straw and its conversion into energy, there’s this from a Nov. 14, 2014 news item on India West.com,

Shaw [CEO Phil Shaw] said Lockheed has come out with waste-to-energy conversion solutions with successful conversion of waste products to electricity, heat and fuel by using gasification processes. He said it was an environmentally friendly green recycling technology, which requires little space and the plants are fully automated.

Getting back to the nanotechnology, I was not able to track down any information about nanotechnology-enabled plastics and Lockheed Martin. But, there is a Dec. 11, 2013 interview with Travis Earles, Lockheed Martin Advanced materials and nanotechnology innovation executive and policy leader, written up by Kris Walker for Azonano. Note: this is a general interview and focuses largely on applications for carbon nanotubes and graphene.

A multiferroic material for more powerful solar cells

A Nov. 12, 2014 INRS (Institut national de la recherche scientifique; Université du Québec) news release (also on EurekAlert), describes new work on solar cells from Federico Rosei’s laboratory (Note: Links have been removed; A French language version of the news release can be found here),

Applying a thin film of metallic oxide significantly boosts the performance of solar panel cells—as recentlydemonstrated by Professor Federico Rosei and his team at the Énergie Matériaux Télécommunications Research Centre at Institut national de la recherche scientifique (INRS). The researchers have developed a new class of materials comprising elements such as bismuth, iron, chromium, and oxygen. These“multiferroic” materials absorb solar radiation and possess unique electrical and magnetic properties. This makes them highly promising for solar technology, and also potentially useful in devices like electronic sensors and flash memory drives. …

The INRS research team discovered that by changing the conditions under which a thin film of these materials is applied, the wavelengths of light that are absorbed can be controlled. A triple-layer coating of these materials—barely 200 nanometres thick—captures different wavelengths of light. This coating converts much more light into electricity than previous trials conducted with a single layer of the same material. With a conversion efficiency of 8.1% reported by [Riad] Nechache and his coauthors, this is a major breakthrough in the field.

The team currently envisions adding this coating to traditional single-crystal silicon solar cells (currently available on the market). They believe it could increase maximum solar efficiency by 18% to 24% while also boosting cell longevity. As this technology draws on a simplified structure and processes, as well as abundant and stable materials, new photovoltaic (PV) cells will be more powerful and cost less. This means that the INRS team’s breakthrough may make it possible to reposition silicon PV cells at the forefront of the highly competitive solar energy market.

Here’s a link to and a citation for the paper,

Bandgap tuning of multiferroic oxide solar cells by R. Nechache, C. Harnagea, S. Li, L. Cardenas, W. Huang,  J. Chakrabartty, & F. Rosei. Nature Photonics (2014) doi:10.1038/nphoton.2014.255 Published online
10 November 2014

This paper is behind a paywall although there is a free preview via ReadCube Access.

I last mentioned Federico Rose in a March 4, 2014 post about a talk (The exploration of the role of nanoscience in tomorrow’s energy solutions) he was giving in Vancouver (Canada).

Super-capacitors on automobiles

Queensland University of Technology* (QUT; Australia) researchers are hopeful they can adapt supercapacitors in the form of a fine film tor use in electric vehicles making them more energy-efficient. From a Nov. 6, 2014 news item on ScienceDaily,

A car powered by its own body panels could soon be driving on our roads after a breakthrough in nanotechnology research by a QUT team.

Researchers have developed lightweight “supercapacitors” that can be combined with regular batteries to dramatically boost the power of an electric car.

The discovery was made by Postdoctoral Research Fellow Dr Jinzhang Liu, Professor Nunzio Motta and PhD researcher Marco Notarianni, from QUT’s Science and Engineering Faculty — Institute for Future Environments, and PhD researcher Francesca Mirri and Professor Matteo Pasquali, from Rice University in Houston, in the United States.

A Nov. 6, 2014 QUT news release, which originated the news item, describes supercapacitors, the research, and the need for this research in more detail,

The supercapacitors – a “sandwich” of electrolyte between two all-carbon electrodes – were made into a thin and extremely strong film with a high power density.

The film could be embedded in a car’s body panels, roof, doors, bonnet and floor – storing enough energy to turbocharge an electric car’s battery in just a few minutes.

“Vehicles need an extra energy spurt for acceleration, and this is where supercapacitors come in. They hold a limited amount of charge, but they are able to deliver it very quickly, making them the perfect complement to mass-storage batteries,” he said.

“Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared to several hours for a standard electric car battery.”

Dr Liu said currently the “energy density” of a supercapacitor is lower than a standard lithium ion (Li-Ion) battery, but its “high power density”, or ability to release power in a short time, is “far beyond” a conventional battery.

“Supercapacitors are presently combined with standard Li-Ion batteries to power electric cars, with a substantial weight reduction and increase in performance,” he said.

“In the future, it is hoped the supercapacitor will be developed to store more energy than a Li-Ion battery while retaining the ability to release its energy up to 10 times faster – meaning the car could be entirely powered by the supercapacitors in its body panels.

“After one full charge this car should be able to run up to 500km – similar to a petrol-powered car and more than double the current limit of an electric car.”

Dr Liu said the technology would also potentially be used for rapid charges of other battery-powered devices.

“For example, by putting the film on the back of a smart phone to charge it extremely quickly,” he said.

The discovery may be a game-changer for the automotive industry, with significant impacts on financial, as well as environmental, factors.

“We are using cheap carbon materials to make supercapacitors and the price of industry scale production will be low,” Professor Motta said.

“The price of Li-Ion batteries cannot decrease a lot because the price of Lithium remains high. This technique does not rely on metals and other toxic materials either, so it is environmentally friendly if it needs to be disposed of.”

A Nov. 10, 2014 news item on Azonano describes the Rice University (Texas, US) contribution to this work,

Rice University scientist Matteo Pasquali and his team contributed to two new papers that suggest the nano-infused body of a car may someday power the car itself.

Rice supplied high-performance carbon nanotube films and input on the device design to scientists at the Queensland University of Technology in Australia for the creation of lightweight films containing supercapacitors that charge quickly and store energy. The inventors hope to use the films as part of composite car doors, fenders, roofs and other body panels to significantly boost the power of electric vehicles.

A Nov. 7, 2014 Rice University news release, which originated the news item, offers a few technical details about the film being proposed for use as a supercapacitor on car panels,

Researchers in the Queensland lab of scientist Nunzio Motta combined exfoliated graphene and entangled multiwalled carbon nanotubes combined with plastic, paper and a gelled electrolyte to produce the flexible, solid-state supercapacitors.

“Nunzio’s team is making important advances in the energy-storage area, and we were glad to see that our carbon nanotube film technology was able to provide breakthrough current collection capability to further improve their devices,” said Pasquali, a Rice professor of chemical and biomolecular engineering and chemistry. “This nice collaboration is definitely bottom-up, as one of Nunzio’s Ph.D. students, Marco Notarianni, spent a year in our lab during his Master of Science research period a few years ago.”

“We built on our earlier work on CNT films published in ACS Nano, where we developed a solution-based technique to produce carbon nanotube films for transparent electrodes in displays,” said Francesca Mirri, a graduate student in Pasquali’s research group and co-author of the papers. “Now we see that carbon nanotube films produced by the solution-processing method can be applied in several areas.”

As currently designed, the supercapacitors can be charged through regenerative braking and are intended to work alongside the lithium-ion batteries in electric vehicles, said co-author Notarianni, a Queensland graduate student.

“Vehicles need an extra energy spurt for acceleration, and this is where supercapacitors come in. They hold a limited amount of charge, but with their high power density, deliver it very quickly, making them the perfect complement to mass-storage batteries,” he said.

Because hundreds of film supercapacitors are used in the panel, the electric energy required to power the car’s battery can be stored in the car body. “Supercapacitors offer a high power output in a short time, meaning a faster acceleration rate of the car and a charging time of just a few minutes, compared with several hours for a standard electric car battery,” Notarianni said.

The researchers foresee such panels will eventually replace standard lithium-ion batteries. “In the future, it is hoped the supercapacitor will be developed to store more energy than an ionic battery while retaining the ability to release its energy up to 10 times faster – meaning the car would be powered by the supercapacitors in its body panels,” said Queensland postdoctoral researcher Jinzhang Liu.

Here’s an image of graphene infused with carbon nantoubes used in the supercapacitor film,

A scanning electron microscope image shows freestanding graphene film with carbon nanotubes attached. The material is part of a project to create lightweight films containing super capacitors that charge quickly and store energy. Courtesy of Nunzio Motta/Queensland University of Technology - See more at: http://news.rice.edu/2014/11/07/supercharged-panels-may-power-cars/#sthash.0RPsIbMY.dpuf

A scanning electron microscope image shows freestanding graphene film with carbon nanotubes attached. The material is part of a project to create lightweight films containing super capacitors that charge quickly and store energy. Courtesy of Nunzio Motta/Queensland University of Technology

Here are links to and citations for the two papers published by the researchers,

Graphene-based supercapacitor with carbon nanotube film as highly efficient current collector by Marco Notarianni, Jinzhang Liu, Francesca Mirri, Matteo Pasquali, and Nunzio Motta. Nanotechnology Volume 25 Number 43 doi:10.1088/0957-4484/25/43/435405

High performance all-carbon thin film supercapacitors by Jinzhang Liu, Francesca Mirri, Marco Notarianni, Matteo Pasquali, and Nunzio Motta. Journal of Power Sources Volume 274, 15 January 2015, Pages 823–830 DOI: 10.1016/j.jpowsour.2014.10.104

Both articles are behind paywalls.

One final note, Dexter Johnson provides some insight into issues with graphene-based supercapacitors and what makes this proposed application attractive in his Nov. 7, 2014 post on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website; Note: Links have been removed),

The hope has been that someone could make graphene electrodes for supercapacitors that would boost their energy density into the range of chemical-based batteries. The supercapacitors currently on the market have on average an energy density around 28 Wh/kg, whereas a Li-ion battery holds about 200Wh/kg. That’s a big gap to fill.

The research in the field thus far has indicated that graphene’s achievable surface area in real devices—the factor that determines how many ions a supercapacitor electrode can store, and therefore its energy density—is not any better than traditional activated carbon. In fact, it may not be much better than a used cigarette butt.

Though graphene may not help increase supercapacitors’ energy density, its usefulness in this application may lie in the fact that its natural high conductivity will allow superconductors to operate at higher frequencies than those that are currently on the market. Another likely benefit that graphene will yield comes from the fact that it can be structured and scaled down, unlike other supercapacitor materials.

I recommend reading Dexter’s commentary in its entirety.

*’University of Queensland’ corrected to “Queensland University of Technology’ on Nov. 10, 2014 at 1335 PST.

Bomb-sniffing and other sniffing possibilities from Utah (US state)

A Nov. 4, 2014 news item on Phys.org features some research in Utah on the use of carbon nanotubes for sensing devices,

University of Utah engineers have developed a new type of carbon nanotube material for handheld sensors that will be quicker and better at sniffing out explosives, deadly gases and illegal drugs.

A carbon nanotube is a cylindrical material that is a hexagonal or six-sided array of carbon atoms rolled up into a tube. Carbon nanotubes are known for their strength and high electrical conductivity and are used in products from baseball bats and other sports equipment to lithium-ion batteries and touchscreen computer displays.

Vaporsens, a university spin-off company, plans to build a prototype handheld sensor by year’s end and produce the first commercial scanners early next year, says co-founder Ling Zang, a professor of materials science and engineering and senior author of a study of the technology published online Nov. 4 [2014] in the journal Advanced Materials.

The new kind of nanotubes also could lead to flexible solar panels that can be rolled up and stored or even “painted” on clothing such as a jacket, he adds.

Here’s Ling Zang holding a prototype of the device,

Ling Zang, a University of Utah professor of materials science and engineering, holds a prototype detector that uses a new type of carbon nanotube material for use in handheld scanners to detect explosives, toxic chemicals and illegal drugs. Zang and colleagues developed the new material, which will make such scanners quicker and more sensitive than today’s standard detection devices. Ling’s spinoff company, Vaporsens, plans to produce commercial versions of the new kind of scanner early next year. Courtesy: University of Utah

Ling Zang, a University of Utah professor of materials science and engineering, holds a prototype detector that uses a new type of carbon nanotube material for use in handheld scanners to detect explosives, toxic chemicals and illegal drugs. Zang and colleagues developed the new material, which will make such scanners quicker and more sensitive than today’s standard detection devices. Ling’s spinoff company, Vaporsens, plans to produce commercial versions of the new kind of scanner early next year. Courtesy: University of Utah

A Nov. 4, 2014 University of Utah news release (also on EurekAlert), which originated the news item, provides more detail about the research,

Zang and his team found a way to break up bundles of the carbon nanotubes with a polymer and then deposit a microscopic amount on electrodes in a prototype handheld scanner that can detect toxic gases such as sarin or chlorine, or explosives such as TNT.

When the sensor detects molecules from an explosive, deadly gas or drugs such as methamphetamine, they alter the electrical current through the nanotube materials, signaling the presence of any of those substances, Zang says.

“You can apply voltage between the electrodes and monitor the current through the nanotube,” says Zang, a professor with USTAR, the Utah Science Technology and Research economic development initiative. “If you have explosives or toxic chemicals caught by the nanotube, you will see an increase or decrease in the current.”

By modifying the surface of the nanotubes with a polymer, the material can be tuned to detect any of more than a dozen explosives, including homemade bombs, and about two-dozen different toxic gases, says Zang. The technology also can be applied to existing detectors or airport scanners used to sense explosives or chemical threats.

Zang says scanners with the new technology “could be used by the military, police, first responders and private industry focused on public safety.”

Unlike the today’s detectors, which analyze the spectra of ionized molecules of explosives and chemicals, the Utah carbon-nanotube technology has four advantages:

• It is more sensitive because all the carbon atoms in the nanotube are exposed to air, “so every part is susceptible to whatever it is detecting,” says study co-author Ben Bunes, a doctoral student in materials science and engineering.

• It is more accurate and generates fewer false positives, according to lab tests.

• It has a faster response time. While current detectors might find an explosive or gas in minutes, this type of device could do it in seconds, the tests showed.

• It is cost-effective because the total amount of the material used is microscopic.

This study was funded by the Department of Homeland Security, Department of Defense, National Science Foundation and NASA. …

Here’s a link to and a citation for the research paper,

Photodoping and Enhanced Visible Light Absorption in Single-Walled Carbon Nanotubes Functionalized with a Wide Band Gap Oligomer by Benjamin R. Bunes, Miao Xu, Yaqiong Zhang, Dustin E. Gross, Avishek Saha, Daniel L. Jacobs, Xiaomei Yang, Jeffrey S. Moore, and Ling Zang. Advanced Materials DOI: 10.1002/adma.201404112 Article first published online: 4 NOV 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

For anyone curious about Vaporsens, you can find more here.

Solar cells and ‘tinkertoys’

A Nov. 3, 2014 news item on Nanowerk features a project researchers hope will improve photovoltaic efficiency and make solar cells competitive with other sources of energy,

 Researchers at Sandia National Laboratories have received a $1.2 million award from the U.S. Department of Energy’s SunShot Initiative to develop a technique that they believe will significantly improve the efficiencies of photovoltaic materials and help make solar electricity cost-competitive with other sources of energy.

The work builds on Sandia’s recent successes with metal-organic framework (MOF) materials by combining them with dye-sensitized solar cells (DSSC).

“A lot of people are working with DSSCs, but we think our expertise with MOFs gives us a tool that others don’t have,” said Sandia’s Erik Spoerke, a materials scientist with a long history of solar cell exploration at the labs.

A Nov. 3, 2014 Sandia National Laboratories news release, which originated the news item, describes the project and the technology in more detail,

Sandia’s project is funded through SunShot’s Next Generation Photovoltaic Technologies III program, which sponsors projects that apply promising basic materials science that has been proven at the materials properties level to demonstrate photovoltaic conversion improvements to address or exceed SunShot goals.

The SunShot Initiative is a collaborative national effort that aggressively drives innovation with the aim of making solar energy fully cost-competitive with traditional energy sources before the end of the decade. Through SunShot, the Energy Department supports efforts by private companies, universities and national laboratories to drive down the cost of solar electricity to 6 cents per kilowatt-hour.

DSSCs provide basis for future advancements in solar electricity production

Dye-sensitized solar cells, invented in the 1980s, use dyes designed to efficiently absorb light in the solar spectrum. The dye is mated with a semiconductor, typically titanium dioxide, that facilitates conversion of the energy in the optically excited dye into usable electrical current.

DSSCs are considered a significant advancement in photovoltaic technology since they separate the various processes of generating current from a solar cell. Michael Grätzel, a professor at the École Polytechnique Fédérale de Lausanne in Switzerland, was awarded the 2010 Millennium Technology Prize for inventing the first high-efficiency DSSC.

“If you don’t have everything in the DSSC dependent on everything else, it’s a lot easier to optimize your photovoltaic device in the most flexible and effective way,” explained Sandia senior scientist Mark Allendorf. DSSCs, for example, can capture more of the sun’s energy than silicon-based solar cells by using varied or multiple dyes and also can use different molecular systems, Allendorf said.

“It becomes almost modular in terms of the cell’s components, all of which contribute to making electricity out of sunlight more efficiently,” said Spoerke.

MOFs’ structure, versatility and porosity help overcome DSSC limitations

Though a source of optimism for the solar research community, DSSCs possess certain challenges that the Sandia research team thinks can be overcome by combining them with MOFs.

Allendorf said researchers hope to use the ordered structure and versatile chemistry of MOFs to help the dyes in DSSCs absorb more solar light, which he says is a fundamental limit on their efficiency.

“Our hypothesis is that we can put a thin layer of MOF on top of the titanium dioxide, thus enabling us to order the dye in exactly the way we want it,” Allendorf explained. That, he said, should avoid the efficiency-decreasing problem of dye aggregation, since the dye would then be locked into the MOF’s crystalline structure.

MOFs are highly-ordered materials that also offer high levels of porosity, said Allendorf, a MOF expert and 29-year veteran of Sandia. He calls the materials “Tinkertoys for chemists” because of the ease with which new structures can be envisioned and assembled. [emphasis mine]

Allendorf said the unique porosity of MOFs will allow researchers to add a second dye, placed into the pores of the MOF, that will cover additional parts of the solar spectrum that weren’t covered with the initial dye. Finally, he and Spoerke are convinced that MOFs can help improve the overall electron charge and flow of the solar cell, which currently faces instability issues.

“Essentially, we believe MOFs can help to more effectively organize the electronic and nano-structure of the molecules in the solar cell,” said Spoerke. “This can go a long way toward improving the efficiency and stability of these assembled devices.”

In addition to the Sandia team, the project includes researchers at the University of Colorado-Boulder, particularly Steve George, an expert in a thin film technology known as atomic layer deposition.

The technique, said Spoerke, is important in that it offers a pathway for highly controlled materials chemistry with potentially low-cost manufacturing of the DSSC/MOF process.

“With the combination of MOFs, dye-sensitized solar cells and atomic layer deposition, we think we can figure out how to control all of the key cell interfaces and material elements in a way that’s never been done before,” said Spoerke. “That’s what makes this project exciting.”

Here’s a picture showing an early Tinkertoy set,

Original Tinkertoy, Giant Engineer #155. Questor Education Products Co., c.1950 [downloaded from http://en.wikipedia.org/wiki/Tinkertoy#mediaviewer/File:Tinkertoy_300126232168.JPG]

Original Tinkertoy, Giant Engineer #155. Questor Education Products Co., c.1950 [downloaded from http://en.wikipedia.org/wiki/Tinkertoy#mediaviewer/File:Tinkertoy_300126232168.JPG]

The Tinkertoy entry on Wikipedia has this,

The Tinkertoy Construction Set is a toy construction set for children. It was created in 1914—six years after the Frank Hornby’s Meccano sets—by Charles H. Pajeau and Robert Pettit and Gordon Tinker in Evanston, Illinois. Pajeau, a stonemason, designed the toy after seeing children play with sticks and empty spools of thread. He and Pettit set out to market a toy that would allow and inspire children to use their imaginations. At first, this did not go well, but after a year or two over a million were sold.

Shrinky Dinks, tinkertoys, Lego have all been mentioned here in conjunction with lab work. I’m always delighted to see scientists working with or using children’s toys as inspiration of one type or another.

Friendlier (halogen-free) lithium-ion batteries

An Oct. 24, 2014 news item on ScienceDaily mentions a greener type of lithium-ion battery from a theoretical (keep reading till you reach the first paragraph of the university news release) perspective,

Physics researchers at Virginia Commonwealth University have discovered that most of the electrolytes used in lithium-ion batteries — commonly found in consumer electronic devices — are superhalogens, and that the vast majority of these electrolytes contain toxic halogens.

At the same time, the researchers also found that the electrolytes in lithium-ion batteries (also known as Li-ion batteries) could be replaced with halogen-free electrolytes that are both nontoxic and environmentally friendly.

“The significance [of our findings] is that one can have a safer battery without compromising its performance,” said lead author Puru Jena, Ph.D., distinguished professor in the Department of Physics of the College of Humanities and Sciences. “The implication of our research is that similar strategies can also be used to design cathode materials in Li-ion batteries.”

An Oct. 24, 2014 Virginia Commonwealth University news release by Brian McNeill (also on EurekAlert), which originated the news item, describes the researchers’ hopes and the inspiration for this work,

“We hope that our theoretical prediction will stimulate experimentalists to synthesize halogen-free salts which will then lead manufacturers to use such salts in commercial applications,” he said.

The researchers also found that the procedure outlined for Li-ion batteries is equally valid for other metal-ion batteries, such as sodium-ion or magnesium-ion batteries.

Jena became interested in the topic several months ago when he saw a flyer on Li-ion batteries that mentioned the need for halogen-free electrolytes.

“I had not done any work on Li-ion batteries at the time, but I was curious to see what the current electrolytes are,” he said. “I found that the negative ions that make up the electrolytes are large and complex in nature and they contain one less electron than what is needed for electronic shell closure.”

Jena had already been working for more than five years on superhalogens, a class of molecules that mimic the chemistry of halogens but have electron affinities that are much larger than that of the halogen atoms.

“I knew of many superhalogen molecules that do not contain a single halogen atom,” he said. “My immediate thought was first to see if the anionic components of the current electrolytes are indeed superhalogens. And, if so, do the halogen-free superhalogens that we knew serve the purpose as halogen-free electrolytes? Our research proved that to be the case.”

Here’s a link to and a citation for the paper,

Superhalogens as Building Blocks of Halogen-Free Electrolytes in Lithium-Ion Batteries by Dr. Santanab Giri, Swayamprabha Behera and Prof. Puru Jena. Angewandte Chemie, DOI: 10.1002/ange.201408648 Article first published online: 14 OCT 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.