Scientists have isolated cyclocarbons for the first time, and aim to use these molecules to build new materials
Post Syndicated from Dexter Johnson original https://spectrum.ieee.org/nanoclast/semiconductors/optoelectronics/thinnest-optical-waveguide
Researchers produce an optical waveguide that reaches the theoretical limit in thinness for the device
New ability to image molecules under charging promises big changes for molecular electronics and organic photovolatics
All living systems depend on the charging and discharging of molecules to convert and transport energy. While science has revealed many of the fundamental mechanisms of how this occurs, one area has remained shrouded in mystery: How does a molecule’s structure change while charging? The answer could have implications for range of applications including molecular electronics and organic photovoltaics.
Now a team of researchers from IBM Research in Zurich, the University of Santiago de Compostela and ExxonMobil has reported in the journal Science the ability to image, with unprecedented resolution, the structural changes that occur to individual molecules upon charging.
This ability to peer into this previously unobserved phenomenon should reveal the molecular charge-function relationships and how they relate to biological systems converting and transporting energy. This understanding could play a critical role in the development of both organic electronic and photovoltaic devices.
“Molecular charge transition is at the heart of many important phenomena, such as photoconversion, energy and molecular transport, catalysis, chemical synthesis, molecular electronics, to name some,” said Leo Gross, research staff member at IBM Zurich and co-author of the research. “Improving our understanding of how the charging affects the structure and function of molecules will improve our understanding of these fundamental phenomena.”
This latest breakthrough is based on research going back 10 years when Gross and his colleagues developed a technique to resolve the structure of molecules with an atomic force microscope. AFMs map the surface of a material by recording the vertical displacement necessary to maintain a constant force on the cantilevered probe tip as it scans a sample’s surface.
Over the years, Gross and his colleagues refined the technique so it could see the charge distribution inside a molecule, and then were able to get it to distinguish between individual bonds of a molecule.
The trick to these techniques was to functionalize the tip of the AFM probe with a single carbon monoxide (CO) molecule. Last year, Gross and his colleague Shadi Fatayer at IBM Zurich believed that the ultra-high resolution possible with the CO tips could be combined with controlling the charge of the molecule being imaged.
“The main hurdle was in combining two capabilities, the control and manipulation of the charge states of molecules and the imaging of molecules with atomic resolution,” said Fatayer.
The concern was that the functionalization of the tip would not be able to withstand the applied bias voltages used in the experiment. Despite these concerns, Fatayer explained that they were able to overcome the challenges in combining these two capabilities by using multi-layer insulating films, which avoid charge leakage and allow charge state control of molecules.
The researchers were able to control the charge-state by attaching single electrons from the AFM tip to the molecule, or vice-versa. This was achieved by applying a voltage between the tip and the molecule. “We know when an electron is attached or removed from the molecule by observing changes in the force signal,” said Fatayer.
The IBM researchers expect that this research could have an impact in the fundamental understanding of single-electron based and molecular devices. This field of molecular electronics promises a day when individual molecules become the building blocks of electronics.
Another important prospect of the research, according to Fatayer and Gross, would be its impact on organic photovoltaic devices. Organic photovoltaics have been a tantalizing solution for solar power because they are cheap to manufacture. However, organic solar cells have been notoriously poor compared to silicon solar cells at converting sunlight to energy efficiently.
The hope is that by revealing how the structural changes of molecules under charge impact the charge transition of molecules, engineers will be able to further optimize organic photovoltaics.
Post Syndicated from Dexter Johnson original https://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/is-graphene-by-any-other-name-still-graphene
Consumers may finally have a way to know if their graphene-enabled products actually get any benefit from the wonder material
Last year, the graphene community was rocked by a series of critical articles that appeared in some high-profile journals. First there was an Advanced Material’s article with the rather innocuously title: “The Worldwide Graphene Flake Production”. It was perhaps the follow-up article that appeared in the journal Nature that really shook things up with its incendiary title: “The war on fake graphene”.
In these two articles it was revealed that material that had been claimed to be high-quality (and high-priced) graphene was little more than graphite powder. Boosted by their appearance in high-impact journals, these articles threatened the foundations of the graphene marketplace.
But while these articles triggered a lot of hand wringing among the buyers and sellers of graphene, it’s not clear that their impact extended much beyond the supply chain of graphene. Whether or not graphene has aggregated back to being graphite is one question. An even bigger one is whether or not consumers are actually being sold a better product on the basis that it incorporates graphene.
Consumer products featuring graphene today include everything from headphones to light bulbs. Consequently, there is already confusion among buyers about the tangible benefits graphene is supposed to provide. And of course the situation becomes even worse if the graphene sold to make products may not even be graphene: how are consumers supposed to determine whether graphene infuses their products with anything other than a buzzword?
Another source of confusion arises because when graphene is incorporated into a product it is effectively a different animal from graphene in isolation. There is ample scientific evidence that graphene when included in a material matrix, like a polymer or even paper, can impart new properties to the materials. “You can transfer some very useful properties of graphene into other materials by adding graphene, but just because the resultant material contains graphene it does not mean it will behave like free-standing graphene, explains Tom Eldridge, of UK-based Fullerex, a consultancy that provides companies with information on how to include graphene in a material matrix.
Eldridge added: “This is why it is often misleading to talk about the superlative properties of free-standing graphene for benefiting applications, because almost always graphene is being combined with other materials. For instance, if I combine graphene with concrete I will not get concrete which is 200 times stronger than steel.”
This is what leaves consumers a bit lost at sea: Graphene can provide performance improvements to a product, but what kind and by how much?
The Graphene Council (Disclosure: The author of this story has also worked for The Graphene Council) recognized this knowledge gap in the market and has just launched a “Verified Graphene Product” Program in addition to its “Verified Graphene Producer” program. The Verified Graphene Producer program takes raw samples of graphene and characterizes them to verify the type of graphene it is, while the Verified Graphene Product program addresses the issue of what graphene is actually doing in products that claim to use it.
Companies that are marketing products that claim to be enhanced by graphene can use this service, and the verification can be applied to their product to give buyers confidence that graphene is actually doing something. (It’s not known if there are any clients taking advantage of it yet.)
“Consumers want to know that the products they purchase are genuine and will perform as advertised,” said Terrance Barkan, executive director of The Graphene Council. “This applies equally to purchasers of graphene enhanced materials and applications. This is why independent, third-party verification is needed.”
The confusion around the United Kingdom’s future is already a factor in recruitment
The European Union and the United Kingdom have been embroiled in Brexit for the last few years, with no clear end in sight. The UK’s withdrawal from the EU has been postponed twice, and is currently set for 31 October, but disarray within the British government means that no one is sure if the UK will leave on that date, or if it does, under what terms.
The fear of a no-deal Brexit—in which the UK crashes out of the EU with no agreed arrangements—looms over all. The result has been a lot of confusion for both businesses and workers, especially those in industries with a relatively mobile workforce, such as tech.
Consequently, tech recruitment firms based in countries that will still be part of the EU after Brexit, such as the Republic of Ireland, have seen an uptick in activity.
“We set this company up two years ago and we’ve been consistently busy,” says Cian Crosse, managing director of Dublin-based nineDots, a technology recruitment firm. “But now we’re mental busy. And the taps just don’t seem to turn off, which is great for us.”
Traditionally, in the movement of tech workers between the UK and Ireland, it was rare for people move from the UK to Ireland, according to Rose Farrell, a senior recruiter at nineDots.
“I don’t think I’ve ever heavily recruited from the UK,” explains Farrell. “People in the tech industry in the UK prefer to work on contract basis. And the rates are much, much higher than the Irish market can pay so we just can’t afford them.”
However, the job market dynamics between Ireland and the UK is changing, according to both Crosse and Farrell, with a lot more movement now from the UK to Ireland.
“Before, we just ignored the UK market for employees, but now it just makes sense for us to start approaching these people as well,” says Crosse. UK-based workers “are a lot more open to the prospect at this point.”
Crosse and Farrell have also witnessed a substantial increase in multinational firms, such as Barclays, opening offices in Ireland as a way to protect themselves from whatever may be facing them in the UK. The issue for multinationals that are headquartered in the UK, or even run a large part of their operations out of the UK, is that that they don’t know if they are going to have access to the entire EU employee pool, or only the pool available in the UK, according to Crosse.
“It has just made more sense for a number of companies from the UK to set up their operations here in Ireland,” says Crosse. After so many years of uncertainty, whether or not a no-deal Brexit ultimately occurs, or even if Brexit is suspended, “I think companies have kind of said, ‘They’ve made their bed. They can lie in it,’ so to speak,” says Crosse.
This Brexit uncertainty is also affecting non-EU multinationals. Ireland has long been attractive for multinationals because of its relatively low corporate tax rate. However, Crosse believes he’s witnessing something different because of Brexit.
“We’ve been helping some large US-based companies get established in Europe,” said Crosse. “They were looking at the UK, but it just makes more sense for them to set up here along with everybody else in the EU. Ireland has the highest pro-EU sentiment in the EU, so companies can actually feel confident setting up here.”
Crosse further explains that Ireland is also attractive for US-based companies because if Brexit goes ahead, Ireland will be the only primarily English-speaking country in the EU.
This rosy picture for the Ireland has its drawbacks, including potential economic and political impacts arising from the re-imposition of border controls between the Republic and Northern Ireland. There is also a continuing housing crisis, and the recent influx of multinationals setting up in Ireland has exacerbated the problem.
“When we start talking to both companies and employees, one of the first things we have to discuss is how expensive housing has become in Ireland,” says Crosse.
To address this issue, some of the multinationals are offering relocation packages that include two or three months of accommodation. “Companies want to make sure that the people they recruit have some place live when the arrive with their bags in their hands, so they can hit the ground running in their new job,” says Crosse.
Six years into an ambitious 10-year research project, experts weigh in on whether the Graphene Flagship can help the “wonder material” make it through the Valley of Death
Six years ago, the European Union (EU) embarked on an ambitious project to create a kind of Silicon Valley for the “wonder material” of the last decade: graphene. The project—called the Graphene Flagship—would leverage €1 billion over 10 years to push graphene into commercial markets. The project would bring together academic and industrial research institutes to not only ensure graphene research would be commercialized, but to also make Europe an economic powerhouse for graphene-based technologies.
To this day, the EU’s investment in the Graphene Flagship represents the single largest project in graphene research and development (though some speculate that graphene-related projects in China may have surpassed it). In the past six years, the Graphene Flagship has spawned nine companies and 46 new graphene-based products. Despite these achievements, there remains a sense among critics that the wonder material has not lived up to expectations and the Flagship’s efforts have not done much to change that perception.
Graphene’s unique properties have engendered high expectations in a host of areas, including for advanced composites and new types of electronic devices. While graphene can come in many forms, its purest form is that of a one-atom-thick layer of graphite. This structure has provided the highest thermal conductivity ever recorded—10 times higher than copper. It also has one of the highest intrinsic electron mobilities of any material (the speed at which electrons can travel through a material), which is approximately 100 times greater than silicon—a tantalizing property for electronic applications.
The Graphene Flagship is now more than halfway through its 10-year funding cycle. To many observers, the project’s achievements—or lack thereof—is a barometer for the commercial status of graphene, which was first synthesized at the UK’s University of Manchester in 2004, earning its discoverers the Nobel Prize in 2010. When it was founded, the Flagship wrestled with a key question that it still faces today: Was the Flagship set up to support “fundamental” research or “applied” research in its quest to make Europe the “Graphene Valley” of the world?