New Nanomaterial Maintains Conductivity in 3-D: Supercapacitors

Schematic diagrams showing the synthesis and microstructures of a 3D graphene-RACNT fiber. (A) Aluminum wire. (B) Surface anodized aluminum wire (AAO wire). (C) 3D graphene-RACNT structure on the AAO wire. (D) Schematic representation of …more

An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.

The research holds potential for increased energy storage in high efficiency batteries and supercapacitors, increasing the efficiency of energy conversion in solar cells, for lightweight thermal coatings and more. The study is published today in the online journal Science Advances.

In early testing, a three-dimensional (3D) fiber-like supercapacitor made with the uninterrupted fibers of carbon nanotubes and graphene matched or bettered—by a factor of four—the reported record-high capacities for this type of device.

Used as a counter electrode in a dye-sensitized solar cell, the material enabled the cell to convert power with up to 6.8 percent efficiency and more than doubled the performance of an identical cell that instead used an expensive platinum wire counter electrode.

Carbon nanotubes could be highly conductive along the 1D nanotube length and two-dimensional graphene sheets in the 2Dplane. But the materials fall short in a three-dimensional world due to the poor interlayer conductivity, as do two-step processes melding nanotubes and graphene into three dimensions.

“Two-step processes our lab and others developed earlier lack a seamless interface and, therefore, lack the conductance sought,” said Liming Dai, the Kent Hale Smith Professor of Macromolecular Science and Engineering at Case Western Reserve University and a leader of the research.

“In our one-step process, the interface is made with carbon-to-carbon bonding so it looks as if it’s one single graphene sheet,” Dai said. “That makes it an excellent thermal and electrical conductor in all planes.”

Dai has worked for nearly four years with Zhong Lin Wang, the Hightower Chair in Materials Science and Engineering, and Yong Ding, a senior research scientist, at Georgia Institute of Technology; and Zhenhai Xia, professor of materials science and engineering, at the University of North Texas; Ajit Roy, principal materials research engineer in the Materials and Manufacturing Directorate, Air Force Research Laboratory, Dayton; and others on a U.S. Department of Defense-Multidisciplinary University Research Initiative (MURI) program (Joycelyn Harrison, Program Manager). Close collaboration was also made with Yuhua Xue, the Research Associate at CWRU and visiting scholar from the Institute of Advanced Materials for Nano-Bio Applications, School of Ophthalmology & Optometry, Wenzhou Medical University, along with Jia Qu and Hao Chen, professors in the Wenzhou Medical University.

To make the 3-D material, the researchers etched radially aligned nanoholes along the length and circumference of a tiny aluminum wire, then used chemical vapor deposition to cover the surface with graphene using no metal catalyst that could remain in the structure.

“Radially-aligned nanotubes grow in the holes. The graphene that sheathes the wire and nanotube arrays are covalently bonded, forming pure carbon-to-carbon nodal junctions that minimize thermal and electrical resistance,” Wang said.

The architecture yields a huge surface area, adding to the transport properties, the researchers say. Using the Brunauer, Emmett and Teller theory, they calculate the surface area of this architecture to be nearly 527 square meters per gram of material.

Testing showed the material makes an ideal electrode for highly efficient energy storage. Capacitance by area reached as high as 89.4 millifarads per square centimeter and by length, up to 23.9 millifarads per centimeter in the fiber-like supercapacitor.

The properties can be customized. With the one-step process, the material can be made very long, or into a tube with a wider or narrower diameter, and the density of nanotubes can be varied to produce materials with differing properties for different needs.

The material can be used for charge storage in capacitors and batteries or the large surface could enable storage of hydrogen. “The properties could be used for an even wider variety of applications, including sensitive sensors, wearable electronics, thermal management and multifunctional aerospace systems”, Roy said.

The scientists are continuing to explore the properties that can be derived from these single 3D graphene layer fibers and are developing a process for making multilayer fibers.

Explore further: Researchers bring clean energy a step closer

More information: Rationally designed graphene-nanotube 3D architectures with a seamless nodal junction for efficient energy conversion and storage, Science Advances, advances.sciencemag.org/content/1/8/e1400198

Journal reference: Science Advances

MIT: Designer Carbons Are Getting a Boost from Nanotechnology: Application: Batteries, Super-Capacitors, Carbon Capture

Manufactured materials could lead to breakthroughs in batteries, supercapacitors, and eventually carbon-capture systems.

A group of Stanford researchers have come up with a nanoscale “designer carbon” material that can be adjusted to make energy storage devices, solar panels, and potentially carbon capture systems more powerful and efficient.

The designer carbon that has reached the market in recent years shares the Swiss-cheese-like structure of activated carbon, enhancing its ability to catalyze certain chemical reactions and store electrical charges; but it’s “designed” in the sense that the chemical composition of the material, and the size of the pores, can be manipulated to fit specific uses.

The designer carbon tested at Stanford is “both versatile and controllable,” according to Zhenan Bao, a professor of chemical engineering and the senior author of the study, which appeared in the latest issue of the journal ACS Central Science.

“Producing high-surface-area carbons with controlled chemical composition and morphology is really challenging,” says Bao. Other methods currently available, she says, “are either quite expensive or they don’t offer control over the chemical structure and morphology.”

The work of Bao and her team represents the latest step forward in a rapidly advancing field with huge promise for a variety of clean-tech applications. Seattle-based EnerG2, for example, has pioneered designer carbons in several applications, particularly lithium-ion batteries. Replacing graphite in the batteries’ anode with designer carbon has resulted in dramatic performance improvements—up to a 30 percent increase in the batteries’ storage capacity, according to EnerG2 founder and CTO Aaron Feaver.

Essentially, designer carbon material is created by baking a precursor material at very high temperatures and then chemically treating it to produce a porous 3-D structure with an enormous surface area. The Stanford team began with a complex polymer that forms an interconnected framework. The cooking temperature can be adjusted, from 300 ^◦C up to 900 ^◦C, to fine-tune the material’s properties. The result is sheets of carbon that are as little as one nanometer thick, with more than 4,000 square meters of surface area per gram.

Designer carbon usually costs more than other anode materials, particularly graphite, but Bao says the raw materials for the Stanford experiments cost less than $10 for every kilogram of carbon produced.

Nanometer-thick sheets of designer carbon offer increased capabilities for energy storage, solar photovoltaics, and carbon capture.

Two of the most promising applications tested at Stanford are lithium-sulfur batteries and supercapacitors. Lithium-sulfur batteries have several advantages over conventional lithium-ion systems, but also one serious flaw: they tend to leak lithium polysulfide, causing the battery to fail. The nano-sized pores of the designer carbon prevent that from happening.

Supercapacitors are energy-storage devices that charge and discharge at very high rates. Bao’s team found that supercapacitor electrodes with the new carbon had electrical conductivity three times that of ones with conventional activated carbon.

Another form of designer carbon is carbon nanotubes, which could be suitable for a number of applications including energy storage. In 2012, MIT scientist Joel Schindall unveiled a method of growing carbon nanotube “forests” that could produce supercapacitors whose energy-storage capacity rivals that of batteries.

The most far-reaching application for designer carbon, though, would be in carbon capture—a technology that has been talked about for years but has never been economically viable. Designer carbon material with pores of a certain size shows great promise in selecting for carbon dioxide, which would condense onto the surface of the synthetic carbon in a capture system.

“Our synthetic approach gives us a very versatile, tunable material, and we are developing a different version of the carbon that’s highly suitable for carbon capture,” says Bao. That work has just been submitted for publication, she adds.

Editor’s note: This story has been updated to clarify the nanoscale carbon advancement from Stanford.

Report: Global Market for Nanotechnology Products Expected to Reach About $64.2 Billion by 2019

The global market for nanotechnology products was valued at $22.9 billion in 2013 and increased to about $26 billion in 2014. This market is expected to reach about $64.2 billion by 2019, a compound annual growth rate (CAGR) of 19.8% from 2014 to 2019.

This report provides:

• An in-depth analysis of the global market for nanotechnology.
• Analyses of global market trends, with data from 2013, estimates for 2014, and projections of CAGRs through 2019.
• Identification of the segments of the nanotechnology market with the greatest commercial potential in the near to mid-term (2014-2019).
• Information most useful and especially intended for entrepreneurs, investors, venture capitalists, nanotechnology marketing executives, and other readers with a need to know where the nanotechnology market is headed in the next five years.
• Comprehensive company profiles of key players in the market.

SCOPE OF REPORT

The global market for nanotechnology applications will be addressed. Nanotechnology applications are defined comprehensively as the creation and use of materials, devices and systems through the manipulation of matter at scales of less than 100 nanometers. The study covers nanomaterials (nanoparticles, nanotubes, nanostructured materials and nanocomposites), nanotools (nanolithography tools and scanning probe microscopes) and nanodevices (nanosensors and nanoelectronics).

A pragmatic decision was made to exclude certain types of materials and devices from the report that technically fit the definition of nanotechnology. These exceptions include carbon black nanoparticles used to reinforce tires and other rubber products; photographic silver and dye nanoparticles; and activated carbon used for water filtration. These materials were excluded because they have been used for decades, long before the concept of nanotechnology was born, and their huge volumes (especially carbon black and activated carbon) would tend to swamp the newer nanomaterials in the analysis.

In the case of pharmaceutical applications, this report measures the value of the particles that the particle manufacturer receives. Research dollars invested into designing better particles, or better delivery approaches, are not included. The value created through clinical trial success and eventual Food and Drug Administration (FDA) approval and entrance as a prescription drug are not included.

Nanoscale semiconductors are also excluded from the study, although the tools used to create them are included. Unlike carbon black and activated carbon, nanoscale semiconductors are a relatively new development. However, they have been analyzed comprehensively elsewhere and, like carbon black and activated carbon, would tend to overwhelm other nanotechnologies by their sheer volume in the out-years toward 2019.

The study format includes the following major elements:

• Executive summary
• Definitions
• Milestones in the development of nanotechnology
• Current and potential nanotechnology applications
• Applications and end users with the greatest commercial potential through 2019
• Global nanotechnology market trends, 2013 through 2019
• Factors that will influence the long-term development of nanotechnology
• Market shares and industry structure

Download the full report: https://www.reportbuyer.com/product/96617/

Wrapping carbon nanotubes in polymers enhances their performance

Scientists first reported carbon nanotubes in the early 1990s. Since then, these tiny cylinders have been part of the quest to reduce the size of technological devices and their components. Carbon nanotubes (CNTs) have very desirable properties. They are 100 times stronger than steel and one-sixth its weight. They have several times the electrical and thermal conductivity of copper. And they have almost none of the environmental or physical degradation issues common to most metals, such as thermal contraction and expansion or erosion.

CNTs have a tendency to aggregate, forming “clumps” of tubes. To utilize their outstanding properties in applications, they need to be dispersed. But they are insoluble in many liquids, making their even dispersion difficult.

Scientists at Japan’s Kyushu University developed a technique that “exfoliates” aggregated clumps of CNTs and disperses them in solvents. It involves wrapping the tubes in a polymer using a bond that does not involve the sharing of electrons. The technique is called non-covalent polymer wrapping. Whereas sharing electrons through covalent polymer wrapping leads to a more stable bond, it also changes the intrinsic desirable properties of the carbon nanotubes. Non-covalent wrapping is thus considered superior in most cases because it causes minimum damage to the tubes.

The scientists, Dr. Tsuyohiko Fujigaya and Dr. Naotoshi Nakashima, conducted a research review to analyze the various approaches of polymer wrapping and to summarize the applications in which polymer-wrapped carbon nanotubes can be used. Their review has been published in Science and Technology of Advanced Materials (16-2 p24802, 2015).

They found that a wide variety of polymers can be used for the non-covalent wrapping of carbon nanotubes. Recently, many polymer dispersants have indeed been developed that not only disperse the CNTs but also add new functions to them. These polymer dispersants are now widely recognized and utilized in many fields, including biotechnology and energy applications.

Carbon nanotubes wrapped in polymer dispersants are used in many fields, including biotechnology and energy

CNTs that are stably wrapped with biocompatible materials are very attractive in biomedicine, for example, due to their incredible ability to pass biological barriers without generating an immune response. There is thus high potential for polymer-wrapped CNTs in the area of drug delivery.

Also, wrapping carbon nanotubes in polymers improves their photovoltaic functions in solar cells, for example, when the polymers function like a light-receiving pigment.

Because the designs of polymers can be readily tailored, it is expected that the functionality of polymer-wrapped CNTs will be further expanded and that novel applications using them will be developed.

Explore further: Understanding the reinforcing ability of carbon nanotubes

 

Scientists use ‘smallest possible diamonds’ to form ultra-thin nanothreads: Video: Will A Space Elevator Be Possible?

For the first time, scientists have discovered how to produce ultra-thin “diamond nanothreads” that promise extraordinary properties, including strength and stiffness greater than that of today’s strongest nanotubes and polymers. A paper describing this discovery by a research team led by John V. Badding, a professor of chemistry at Penn State, was published in the Sept. 21 issue of the journal Nature Materials.

“From a fundamental-science point of view, our discovery is intriguing because the threads we formed have a structure that has never been seen before,” Badding said. The core of the nanothreads that Badding’s team made is a long, thin strand of carbon atoms arranged just like the fundamental unit of a diamond’s structure—zig-zag “cyclohexane” rings of six carbon atoms bound together, in which each carbon is surrounded by others in the strong triangular-pyramid shape of a tetrahedron. “It is as if an incredible jeweler has strung together the smallest possible diamonds into a long miniature necklace,” Badding said. “Because this thread is diamond at heart, we expect that it will prove to be extraordinarily stiff, extraordinarily strong, and extraordinarily useful.”

The team’s discovery comes after nearly a century of failed attempts by other labs to compress separate carbon-containing molecules like liquid benzene into an ordered, diamond-like nanomaterial. “We used the large high-pressure Paris-Edinburgh device at Oak Ridge National Laboratory to compress a 6-millimeter-wide amount of benzene—a gigantic amount compared with previous experiments,” said Malcolm Guthrie of the Carnegie Institution for Science, a co-author of the research paper. “We discovered that slowly releasing the pressure after sufficient compression at normal room temperature gave the carbon atoms the time they needed to react with each other and to link up in a highly ordered chain of single-file carbon tetrahedrons, forming these diamond-core nanothreads.”

John Badding, professor of chemistry at Penn State, leads a research team that has discovered how to produce super-strong, super-thin “diamond nanothreads” that promise extraordinary properties such as strength and stiffness higher than that of carbon nanotubes or conventional high-strength polymers.

Badding’s team is the first to coax molecules containing carbon atoms to form the strong tetrahedron shape, then link each tetrahedron end to end to form a long, thin nanothread. He describes the thread’s width as phenomenally small, only a few atoms across, hundreds of thousands of times smaller than an optical fiber, enormously thinner that an average human hair. “Theory by our co-author Vin Crespi suggests that this is potentially the strongest, stiffest material possible, while also being light in weight,” he said.

The molecule they compressed is benzene—a flat ring containing six carbon atoms and six hydrogen atoms. The resulting diamond-core nanothread is surrounded by a halo of hydrogen atoms. During the compression process, the scientists report, the flat benzene molecules stack together, bend and break apart. Then, as the researchers slowly release the pressure, the atoms reconnect in an entirely different yet very orderly way. The result is a structure that has carbon in the tetrahedral configuration of diamond with hydrogens hanging out to the side and each tetrahedron bonded with another to form a long, thin, nanothread.

“It really is surprising that this kind of organization happens,” Badding said. “That the atoms of the benzene molecules link themselves together at room temperature to make a thread is shocking to chemists and physicists. Considering earlier experiments, we think that, when the benzene molecule breaks under very high pressure, its atoms want to grab onto something else but they can’t move around because the pressure removes all the space between them. This benzene then becomes highly reactive so that, when we release the pressure very slowly, an orderly polymerization reaction happens that forms the diamond-core nanothread.”

Enlarge

The scientists confirmed the structure of their diamond nanothreads with a number of techniques at Penn State, Oak Ridge, Arizona State University and the Carnegie Institution for Science, including X-ray diffraction, neutron diffraction, Raman spectroscopy, first-principle calculations, transmission electron microscopy and solid-state nuclear magnetic resonance (NMR). Parts of these first diamond nanothreads appear to be somewhat less than perfect, so improving their structure is a continuing goal of Badding’s research program. He also wants to discover how to make more of them. “The high pressures that we used to make the first diamond nanothread material limit our production capacity to only a couple of cubic millimeters at a time, so we are not yet making enough of it to be useful on an industrial scale,” Badding said. “One of our science goals is to remove that limitation by figuring out the chemistry necessary to make these diamond nanothreads under more practical conditions.”

The nanothread also may be the first member of a new class of diamond-like nanomaterials based on a strong tetrahedral core. “Our discovery that we can use the natural alignment of the benzene molecules to guide the formation of this new diamond nanothread material is really interesting because it opens the possibility of making many other kinds of molecules based on carbon and hydrogen,” Badding said. “You can attach all kinds of other atoms around a core of carbon and hydrogen. The dream is to be able to add other atoms that would be incorporated into the resulting nanothread. By pressurizing whatever liquid we design, we may be able to make an enormous number of different materials.”

Enlarge

                                          Credit: Enshi Xu, Vincent H Crespi lab, Penn State

Potential applications that most interest Badding are those that would be vastly improved by having exceedingly strong, stiff and light materials—especially those that could help to protect the atmosphere, including lighter, more fuel-efficient and therefore less-polluting vehicles. “One of our wildest dreams for the nanomaterials we are developing is that they could be used to make the super-strong, lightweight cables that would make possible the construction of a “space elevator”, which so far has existed only as a science-fiction idea,” Badding said.

Explore further: Smallest possible diamonds form ultra-thin nanothreads

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Better Bomb-Sniffing Technology

November 4, 2014 | by Vincent Horiuchi, Univ. of Utah 

Univ. 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. 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.

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 spinoff 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 in 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.

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.

Source: Univ. of Utah

Tiny Carbon Nanotube-Pores Make BIG Impact

Abstract:
A team led by the Lawrence Livermore scientists has created a new kind of ion channel based on short carbon nanotubes, which can be inserted into synthetic bilayers and live cell membranes to form tiny pores that transport water, protons, small ions and DNA.

Livermore, CA | Posted on October 29th, 2014

These carbon nanotube “porins” have significant implications for future health care and bioengineering applications. Nanotube porins eventually could be used to deliver drugs to the body, serve as a foundation of novel biosensors and DNA sequencing applications, and be used as components of synthetic cells.

Researchers have long been interested in developing synthetic analogs of biological membrane channels that could replicate high efficiency and extreme selectivity for transporting ions and molecules that are typically found in natural systems. However, these efforts always involved problems working with synthetics and they never matched the capabilities of biological proteins.

Unlike taking a pill which is absorbed slowly and is delivered to the entire body, carbon nanotubes can pinpoint an exact area to treat without harming the other organs around.

“Many good and efficient drugs that treat diseases of one organ are quite toxic to another,” said Aleksandr Noy, an LLNL biophysicist who led the study and is the senior author on the paper appearing in the Oct. 30 issue of the journal, Nature. “This is why delivery to a particular part of the body and only releasing it there is much better.”

The Lawrence Livermore team, together with colleagues at the Molecular Foundry at the Lawrence Berkeley National Laboratory, University of California Merced and Berkeley campuses, and University of Basque Country in Spain created a new type of a much more efficient, biocompatible membrane pore channel out of a carbon nanotube (CNT) — a straw-like molecule that consists of a rolled up graphene sheet.

This research showed that despite their structural simplicity, CNT porins display many characteristic behaviors of natural ion channels: they spontaneously insert into the membranes, switch between metastable conductance states, and display characteristic macromolecule-induced blockades. The team also found that, just like in the biological channels, local channel and membrane charges could control the ionic conductance and ion selectivity of the CNT porins.

“We found that these nanopores are a promising biomimetic platform for developing cell interfaces, studying transport in biological channels, and creating biosensors,” Noy said. “We are thinking about CNT porins as a first truly versatile synthetic nanopore that can create a range of applications in biology and materials science.”

“Taken together, our findings establish CNT porins as a promising prototype of a synthetic membrane channel with inherent robustness toward biological and chemical challenges and exceptional biocompatibility that should prove valuable for bionanofluidic and cellular interface applications,” said Jia Geng, a postdoc who is the first co-author of the paper.

Kyunghoon Kim, a postdoc and another co-author, added: “We also expect that our CNT porins could be modified with synthetic ‘gates’ to dramatically alter their selectivity, opening up exciting possibilities for their use in synthetic cells, drug delivery and biosensing.”

###

Other LLNL researchers include Ramya Tunuguntla, Kang Rae Cho, Dayannara Munoz and Morris Wang. The team members performed some of the work at the Molecular Foundry DOE user facility as a part of its user project.

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About DOE/Lawrence Livermore National Laboratory
ounded in 1952, Lawrence Livermore National Laboratory (http://www.llnl.gov) provides solutions to our nation’s most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy’s National Nuclear Security Administration.

The Next-Generation Solar PV Materials: ‘Picking the Winners’ that Will Emerge Into the Market

From the newly released NanoMarkets report, “Materials for Next-Generation Photovoltaics – 2014-2021”

The solar panel industry now seems back on track following the boom-and-bust period. It’s still a sector dominated by crystalline silicon, but the current upswing means that the search is on once more for materials platforms that improve the conversion efficiency of solar panels, and efforts have been rebooted to hone and ultimately commercialize these next-generation materials.

Some of them are close at hand, such as novel approaches to doping silicon panels. Meanwhile, the thin-film PV sector continues to seek success against entrenched c-Si; this could come from improvements to CdTe and CIGS, while other thin-film materials are beginning to receive serious commercial attention.

The solar industry also is beginning to think out of the box with a slew of entirely new nanomaterials such as quantum dots, nanowires, nanotubes and graphene.

Here’s a rundown of what we see emerging in next-gen solar PV materials:

Opportunities in Silicon Photovoltaics

The need for better c-Si technology has urged a more aggressive roadmap based on advanced c-Si technologies. Prominent ones gaining traction include n-type cells, back-contact cells, selective emitter options, wrap-through variants, and cells with rear side passivation. We anticipate a scale-up to volume production is likely to occur 2015, when investments are expected to pick up — we currently see the materials market value for advanced c-Si racing ahead from just $16 million in 2014 to $115 million in 2016, and topping $1.5 billion by 2020.

Compared with standard and matured p-type c-Si technology, n-type Si offers better tolerance to common impurities, higher device lifetime, and lesser light-induced degradation, though further research is needed to eliminate non-uniform electrical resistivity and to come up with more effective passivation techniques for charting out a sizable, and cost-effective, production route. Among the potential n-type substrates, PERT, HJ and IBC cell architectures are likely to be investigated further. Wafer thinning (and new ultra-thin wafers), multiple-junction structures, screen printing, and ion implantation also can be routes to develop high-efficiency n-type solar cells.

Although suppliers in Taiwan, the U.S., and Europe have shown signs of adopting higher efficiency c-Si technology, greater adoption in Japan and bigger involvement of Chinese players will be significant to facilitate the migration of standard c-Si technologies to the advanced forms.

Next-generation thin-film PV

Standard thin-film PV has found it hard to compete with conventional c-Si’s relentless cost cuts, pricing pressure, and efficiency improvements. Part of the answer for thin-film PV lies in multi-junction PV cells to utilize more of the available solar spectrum; other avenues include addressing markets where c-Si has disadvantages, such as certain low-light and hot outdoor environments, and in building-integrated photovoltaics (BIPV). Given the ambitious roadmaps of the two thin-film leaders First Solar and Solar Frontier, we expect 2015 could witness active commercial developments as the cost difference between the standard C-Si and existing thin-film technologies narrows. This is especially important as the solar industry shifts toward remote and unsubsidized markets.

Various thin-film technologies are being pursued. CdTe PV cells currently pose a strong challenge to multi-Si cells in terms of efficiency, and should find acceptance in constrained spaces and other related industrial applications — novel and cost-effective approaches for doping, back-contact formation, and printing will be key. Commercial progress with CIGS has been slow due to processing complexities and encapsulation concerns, but in terms of efficiency CIGS is now tantalizingly close to that of single-crystal PV, and new production approaches and methodologies illuminate a path to beat Si-based PV technologies in cost terms. Other emerging thin-film candidates include CZTS (a CIGS variant with a different absorber material), CdMgTe (a II-VI semiconductor alloy), and pyrites.

Collectively, NanoMarkets sees emerging thin-film PV as fledgling in the near term, cracking the $120 million barrier at the far end of our eight-year forecast window (2021).

OPV and DSC

Organic photovoltaic (OPV) cells have been the focus of much research as they are lightweight, flexible, inexpensive, highly tunable, and potentially disposable. Their main advantage is a very high absorption coefficient coupled with the use of low-cost, high-throughput manufacturing techniques (such as inkjet printing and roll-to-roll). Despite the improving performance of OPV cells, there are urgent needs to address: develop large-area monolithic panels, reduce defect density and improve yields, and devise better encapsulation systems to improve OPV module lifetime to at least 10 years.

We think OPV modules need to demonstrate closer to 8% efficiency level and 10 years of lifetime — and ultimately module production costs to below $0.50/watt — within the next five years’ time to be competitive in the marketplace, first in DC portable power devices followed by building integrated PV (BIPV) applications. Part of this will involve commercialization efforts through industry joint collaborative projects, and a specific OPV material-related IP ecosystem with a sea of change of newer players bringing out new materials, such as narrow optical gap photoactive polymers.

Perhaps the most excitement around solar PV materials is around perovskite, which in just a few short years has enjoyed a trajectory of efficiency improvements unlike any other solar PV material — from breaking the 10% barrier in 2012 to 15% in 2013 and nearly 20% already this year, and likely as high as 30% before being commercially rolled out. NanoMarkets sees very important ramifications from perovskite’s unprecedented trajectory for one specific market segment: dye-sensitized solar cells (DSC). Several key DSC firms already have been at the forefront of the perovskite solar revolution. A great deal of research continues into perovskite materials optimization and processing techniques. We believe it is indeed possible that perovskite PV cells could quickly ramp to and beyond the 20% mark and compete against the more established Si counterparts within the next several years.

NanoMarkets sees enough positive signs from this segment of emerging PV — OPV, DSC, and perovskite — that we think it could begin to rival that of aforementioned advanced c-Si by the end of our forecast period, topping $1.1 billion in materials market value.

Nanomaterials for Next-generation PV

Further along the solar PV technology roadmap are a number of nanomaterials which present various attractive options, and challenges that continue to slow their development toward commercialization anytime soon:

– Silver nanowires offer the potential to replace traditional electrode materials due to their intriguing electrical, thermal, and optical properties: an inherent low resistivity, high specular transmittance, superior flexibility, and surface plasmon resonance effect. Despite substantial progress, however, they have yet to find use in commercial use as efficient transparent electrodes that can boost energy conversion efficiency to realistic levels, still demonstrating efficiency below 10%.

– Quantum dots are considered as one of the most attractive candidates for solar PV, thanks to inexpensive low-temperature solution processing techniques and a theoretical energy conversion efficiency of up to 45%. Actual efficiency, however, is still below 10%, so commercial viability is still a long way off — but put another way, there’s still a lot of room for improvement, including ways to pair QDs with other suitable PV materials as co-absorbers in PV cells

– Carbon nanotubes (CNT) are gaining broad interest for their unique properties which can be used effectively for photovoltaic solar cells: easy and inexpensive to manufacture, stable and durable, and both good light absorbers and electrical conductors. CNTs have shown PV cell energy conversion efficiency of up to 80% via an efficient charge transport mechanism inside the cell, and recent advances allow greater level of control over their chemical makeup. In fact CNTs could be on track to be commercially ready before quantum dots — but that’s a relative assessment, because we feel they’re still unlikely to be commercialized for PV applications anytime soon.

– Which brings us to the ever-next-gen material, graphene, which in the case of PV applications has shown promise as absorber and photoactive layer with extreme conductivity and transparency, plus an affinity to keep its properties even after being coated with another conductive material (e.g. silicon or copper). Research initiatives around the use of graphene in PV applications have shifted from treating graphene as a substitute for ITO (in transparent electrodes) to viewing it as a potential conduction layer candidate in the next generation of PV cells. There is a possibility of using it in combination with titanium dioxide as a charge collector, keeping perovskite material as the sunlight absorber in PV cells. Under such an arrangement, cell efficiency of 15.6% has been achieved.

Building an Avant-Technological Tsunami Warning System

Building the ultimate tsunami warning system

 We can’t prevent tsunamis – but a British Columbia project aims to save many thousands of people from their devastationIn addition to being deadly and devastating, tsunamis tend to arrive without much warning. They’re most commonly triggered by undersea earthquakes and landslides. Those are hard to detect, but getting easier thanks to NEPTUNE, an underwater technology network off Canada’s West Coast.

People need tsunami information fast. On the afternoon of March 11, 2011, an 8.95- magnitude earthquake hit off the coast of Japan. Within an hour, 10-metre waves washed the coast, sweeping away cars, crushing buildings and buckling roads as if they were twist-ties. The 2004 tsunami that swept the Indian Ocean, triggering more tsunamis as it rolled along, was just as shocking; it killed more than 230,000 people in 14 countries, and caused the entire planet to vibrate by about a centimetre.

Graphic: Lauren Heintzman

“The problem is, how do you tell people they’re coming, and more importantly, how do you tell what height they’re going to be?” says Benoit Pirenne, Associate Director, Digital Infrastructure at Ocean Networks Canada.

Enter NEPTUNE, or the North-East Pacific Time-series Undersea Networked Experiments.

Headquartered at British Columbia’s University of Victoria, Ocean Networks Canada is using that high-tech underwater, computer-connected system, and others, to map and monitor the seabed — and to improve detection, warning and analysis of the shapes of the giant waves.

NEPTUNE’s backbone is an 800-kilometre loop of power and fibre-optic cables, connected to equipment that measures a host of geological and other processes, deep in the Juan de Fuca Strait off the B.C. coast. The cable network lies atop the smallest of the Earth’s 12 tectonic plates.

The cables are connected to pressure sensors on the seabed, Pirenne explains. “They’re really scales that measure the water column. They do that every second, so you can map, if you will, every wave,” he says.

Up to now, tsunami detection has been spotty. But NEPTUNE promises to deliver a continuous stream of data that is much more detailed and nuanced than what has been traditionally gleaned from ship-based exploration — and that information, Pirenne hopes, will soon be used to revolutionize tsunami detection.

“We have proven that our sensors can detect their waves,” he notes. “We are now working on the software detection systems and on the models that will help predict more precisely the impacts on specific points along the coast of Vancouver Island.” That step would mean far better protection than the minimal warnings that people have received for tsunamis up to now.

The sensor data is transmitted to stations where scientists can analyze the seismic activity to help predict big waves. “Help” is still the operative word. “In a given time range, with three or more sensors, we can identify the source, origin and the speed of a wave coming toward the coast. But it still doesn’t tell you how high the wave will be,” Pirenne says.

Tsunamis can reach as high as 30 metres − three times the height of the initial waves that caused the first devastation in Japan. Determining wave height is the next puzzle to solve, says Pirenne.

“We’re working on a detection system. Waves are influenced by the profile of the seabed as you come close to the coastline; the topography of the water [and the seabed underneath] has a big influence on the final speeds and height.

“It’s important take into account the profile of the coastline to see what the wave is going to be doing − whether it’s going to be a metre or 10 metres, an acre or a square kilometre,” he says.

“We hope to have this part ready by the end of 2016.”

The challenge for scientists now is to move tsunami detection forward from its current state of “near-real-time,” with a few minutes lag, to actual real time, so that when waves are detected everyone can know precisely how much time there is to take emergency action. Another challenge is to provide detection for both “near-field”, imminent tsunamis and “far-field” ones that may be on the way.

The scientists are busy and the work is ongoing, says Virginia Keast, Ocean Networks Canada’s communications officer. Last spring, the organization hosted an international workshop to share the latest advancements in tsunami modeling. And in mid-September, Pirenne was in St. John’s, Newfoundland presenting the network’s progress to other experts.

“We’re sharing what we know with Japan, with South America, with other countries,” says Keast. The 2004 Indian Ocean tsunami was the catalyst for action, she says, and this was reinforced by the Japanese disaster in 2011, which sent detritus and debris across the ocean all the way to B.C.

“Canada has one of the most advanced systems in the world in terms of cable sensors supplying data offshore,” says Pirenne.