Tag Archives: CSI

Nestling a two-element atomic chain inside a carbon nanotube

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While there doesn’t seem to be a short-term application for this research from Japan, the idea of nestling a chain of two elements inside a carbon nanotube is intriguing, from an Oct. 16, 2014 news item on Nanowerk,

Kazutomo Suenaga of the Nanotube Research Center (NTRC) of the National Institute of Advanced Industrial Science and Technology (AIST) and Ryosuke Senga of the Nano-carbon Characterization Team, NTRC, AIST, have synthesized an atomic chain in which two elements are aligned alternately and have evaluated its physical properties on an atomic level.

An ionic crystalline atomic chain of cesium iodine (CsI) has been synthesized by aligning a cesium ion (Cs+), a cation and an iodine ion (I-), an anion, alternately by encapsulating CsI in the microscopic space inside a carbon nanotube. Furthermore, by using an advanced aberration-corrected electron microscope, the physical phenomena unique to the CsI atomic chain, such as the difference in dynamic behavior of its cations and anions, have been discovered. In addition, from theoretical calculation using density functional theory (DFT), this CsI atomic chain has been found to indicate different optical properties from a three-dimensional CsI crystal, and applications to new optical devices are anticipated.

An Oct. 16, 2014 National Institute of Advanced Industrial Science and Technology (AIST) press release, which originated the news item, situates the research within a social and historical context,

Social Background of Research

In the accelerating and ballooning information society, electronic devices used in computers and smartphones has constantly demanded higher performance and efficiency. The materials currently drawing expectations are low-dimensional materials with a single to few-atom width and thickness. Two-dimensional materials, typified by graphene, indicate unique physical characteristics not found in three-dimensional materials, such as its excellent electrical transport properties, and are being extensively researched.

An atomic chain, which has an even finer structure with a width of only one atom, has been predicted to display excellent electrical transport properties, like two-dimensional materials. Although expectations were higher than for two-dimensional materials from the viewpoint of integration, it had attracted little attention until now. This is because of the technological difficulties faced by the various processes of academic research from synthesis to analysis of atomic chains, and academic understanding has not progressed far (Fig. 1).

Figure 1
Figure 1 : Transition of target materials in material research

History of Research

AIST has been developing element analysis methods on a single-atom level to detect certain special structures including impurities, dopants and defects, that affect the properties of low-dimensional materials such as carbon nanotubes and graphene (AIST press releases on July 6, 2009, January 12, 2010, December 16, 2010 and July 9, 2012). In this research, efforts were made for the synthesis and analysis of the atomic chain, a low-dimensional material, using the accumulated technological expertise. This research has been supported by both the Strategic Basic Research Program of the Japan Science and Technology Agency (FY2012 to FY2016), and the Grants-in-aid for Scientific Research of the Japan Society for the Promotion of Science, “Development of elemental technology for the atomic-scale evaluation and application of low-dimensional materials using nano-space” (FY2014 to FY2016).

The press release also offers more details about the research and future applications,

Details of Research

The developed technology is the technology to expose carbon nanotubes, with a diameter of 1 nm or smaller, to CsI vapor to encapsulate CsI in the microscopic space inside the carbon nanotubes, to synthesize an atomic chain in which two elements, Cs and I, are aligned alternately. Furthermore, by combining aberration-corrected electron microscopy and an electronic spectroscopic technique known as electron energy-loss spectroscopy (EELS) detailed structural analysis of this atomic chain was conducted. In order to identify each atom aligned at a distance of 1 nm or less without destroying them, the accelerating voltage of the electron microscope was significantly lowered to 60 kV to reduce damage to the sample by electron beams, while maintaining sufficient spatial resolution of around 1 nm. Figure 2 indicates the smallest CsI crystal confirmed so far, and the CsI atomic chain synthesized in this research.

Figure 2
Figure 2 : Comparison of CsI atomic chain and CsI crystal
(Top: Actual annular dark-field images, Bottom: Corresponding models)

Figure 3 shows the annular dark-field (ADF) image of the CsI atomic chain and the element mapping for Cs and I, respectively, obtained by EELS. It can be seen that the two elements are aligned alternately. There has not been any report of this simple and ideal structure actually being produced and observed, and it can be said to be a fundamental, important finding in material science.

Normally, in an ADF image, those with larger atomic numbers appear brighter. However, in this CsI atomic chain, I (atomic number 53) appears brighter than Cs (atomic number 55). This is because Cs, being a cation, moves more actively (more accurately, the total amount of electrons scattered by the Cs atom is not very different from those of the I atom, but the electrons scattered by the moving Cs atom generate spatial expansion), indicating a difference in dynamic behavior of the cation and the anion that cannot occur in a large three-dimensional crystal. Locations where single Cs atom or I atom is absent, namely vacancies, were also found (Fig. 3, right).

The unique behavior and structure influence various physical properties. When optical absorption spectra were calculated using DFT, the response of the CsI atomic chain to light differed with the direction of incidence. Furthermore, it was found that in a CsI atomic chain with vacancies, the electron state of vacancy sites where the I atom is absent possess a donor level at which electrons were easily released, while vacancy sites where the Cs atom is absent possess a receptor level at which electrons were easily received. By making use of these physical properties, applications to new electro-optical devices, such as a micro-light source and an optical switch using light emission from a single vacancy in the CsI atomic chain, are conceivable. In addition, further research into combinations of other elements triggered by the present results may lead to the development of new materials and device applications. There are expectations for atomic chains to be the next-generation materials for devices in search of further miniaturization and integration.

Figure 3
Figure 3 : Synthesized CsI atomic chain, encapsulated in double-walled carbon nanotube
(From left: ADF image, element maps for Cs and I, model, ADF image of CsI atomic chains with vacancies)

Future Plans

Since the CsI atomic chain displays optical properties significantly different from large crystals that can be seen by the human eye, there are expectations for its application for new electro-optical devices such as a micro-light source and an optical switch using light emission from a single vacancy in the CsI atomic chain. The researchers will conduct experimental research in its application, focused on detailed study of its various physical properties, starting with its optical properties. In addition to CsI, efforts will also be made in the development of new materials that combine various elements, by applying this technology to other materials.

Furthermore, the mechanism of all adsorbents of radioactive substances (carbon nanotubes, zeolite, Prussian blue, etc.) currently being developed for commercial use are methods of encapsulating radioactive atoms inside microscopic space in the material. The researchers hope to utilize the knowledge of the behavior of the Cs atom in a microscopic space obtained in this research, to improve adsorption performance.

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

Atomic structure and dynamic behaviour of truly one-dimensional ionic chains inside ​carbon nanotubes by Ryosuke Senga, Hannu-Pekka Komsa, Zheng Liu, Kaori Hirose-Takai, Arkady V. Krasheninnikov, & Kazu Suenaga. Nature Materials (2014) doi:10.1038/nmat4069 Published online 14 September 2014

This paper is behind a paywall.

The American Chemical Society’s 242nd national meeting, Hollywood, super heroes, and a nano intumescent flame retardant

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Apparently Hollywood came calling at the American Chemical Society’s (ACS) 242nd National Meeting (August 28 – Sept. 1, 2011). They were asking scientists to volunteer as advisors. From the August 29, 2011 news item on Science Daily,

In this International Year of Chemistry (IYC), writers and producers for the most popular crime and science-related television shows and movies are putting out an all-points bulletin for scientists to advise them on the accuracy of their plots involving lab tests, crime scenes, etc., and to even give them story ideas.

They really do want to get it right, and this is very good news for young people who absorb the information from these shows, and this helps shape their positive career decisions. That’s the message delivered in Denver by producers and writers from top television shows speaking at a special Presidential Event at the American Chemical Society’s (ACS) 242nd National Meeting & Exposition.

… They spoke at a symposium entitled “Science on the Hollywood Screen.” In addition to CSI, other shows represented were Breaking Bad, CSI New York, Buffy, Battlestar and Torchwood.

As I recall, Buffy was mainly concerned with slaying vampires. It seems a curious choice but it makes more sense when you see the presentation summaries,

Here are titles of presentations in the “Science on the Hollywood Screen” symposium, with summaries of the presentations:

  • CSI New York: Science personified. Aaron Thomas, Writer, Producer, CSI New York. For writers who do not have a science background, thorough research is essential. The producers of CSI New York go to great lengths ensuring that the stories they tell are grounded in reality. This includes the science and forensic aspects of the show. They base many of their stories on actual cases. The show has an intelligent and diligent staff of assistants who thoroughly cross-check their ideas with the latest science journals and publications to ensure that they are as accurate as possible with their research. Often, ideas that are pitched for episodes of the show begin with interesting science mysteries.
  • CSI: Entertaining science via methodology and analysis. Corrine Marrinan, Writer, Producer, CSI. Forensic chemistry and materials analysis is the cornerstone of any forensic drama, just as it is considered the strongest physical evidence to be presented in a legal case. Accurately depicting these microscopic events in entertainment is considered one of the greatest challenges in on-screen storytelling. Fortunately, advancements in forensic chemistry have developed in tandem with great advancements in the entertainment technology, special effects and computer-generated images. CSI has mastered the visual expression of forensic chemistry in order to make specialized scientific information more accessible to worldwide audiences.
  • Buffy, Battlestar, Torchwood — Chemistry vs. Magic on Sci Fi TV. Jane Espenson, writer, producer for a variety of television shows. While writers do at times attempt to include science, including chemistry, they find that magic, which serves many of the same basic functions as science, is often more adaptable. The presentation will describe a scene showing some well-researched chemistry and will include a montage of clips from various episodes that depict uses of magic, especially chemical-type potions. For chemistry to get more screen time, it would be advantageous for it to more closely resemble magic.
  • Breaking Bad: Factual and fabulous. Donna Nelson, Associate Professor of Chemistry, Massachusetts Institute of Technology (MIT) and the University of Oklahoma. The presentation will describe what it is like to be a chemist adviser for Breaking Bad and explain why more chemists should offer their talents to help producers of science-related shows and movies. Today is the perfect time for more scientists to volunteer, as show producers say they are working to create programs that are as accurate as possible.
  • Damn it, Jim (Cameron) — I’m a screenwriter not a chemist! Ann Merchant, The Science & Entertainment Exchange. The presentation will outline the mission and the history of The Science & Entertainment Exchange and examine some of the realities of the relationship between science and entertainment as a way to explore a “win-win” collaboration. It will cover the origins of The Science & Entertainment Exchange and its expertise in both the entertainment and science communities. It will also describe a “typical” consultation, highlight some of the special events The Exchange has hosted and ground the program objectives in the research on education/entertainment.

I gather the presentations were part of the ACS’s initiative celebrating the International Year of Chemistry as declared by the United Nations.

In a bid to change perceptions about scientists, a special symposium at the 242nd meeting focused on scientists as superheroes. From the August 28, 2011 news item on Nanowerk,

One of the most serious personnel shortages in the global science and engineering workforce — numbering more than 20 million in the United States alone — involves a scarcity of real-life versions of Superman, Superwoman and other superheroes and superheroines with charm, charisma, people skills and communication skills. [emphasis mine]

(Superman seems to be a theme these days. Note the recent relaunch of the Superman and other DC comic heroes in my Sept. 5, 2011 posting.)

Here’s a brief taste of what they were offering,

 

…

Infusing moving media into instruction. Janet English, Instructor, El Toro High School, Mission Viejo, Calif. The main job for movie and TV superheroes is to save the world, and this is why many consider scientists superheroes. There are numerous ways that chemists and other scientists can affect children’s learning and help promote a love of science. The media also can play a pivotal role in students’ learning, and teachers can discuss how the media is used (or not used) in a thought-provoking way in the classroom. Scientists also can contribute to improving the mass media and how they can be role models for children.

Creative engagement at science cafes. John Cohen., M.D., University of Colorado School of Medicine, Department of Immunology, Denver. A Café Scientifique brings a scientist to talk directly with the public in pleasant relaxed surroundings. PowerPoint is banned to encourage dialog, rather than a lecture. There is no moderator, so the conversation finds its correct level without imposed dumbing-down. Speakers frequently say that talking at the Café Sci was one of the best experiences of their career. So do audiences and organizers.

…

The Ig Nobel Prize: Never dull, never boring awards in chemistry. Marc Abrahams, Editor, Annals of Improbable Research. The Ig Nobel Prizes honor achievements that first make people laugh, then make them think. Every year since 1991, 10 new prizes have been awarded in chemistry, physics and other fields. The winners journey to Harvard University for the gala ceremony in which genuine Nobel laureates shake their hands and hand them their prizes. The “Igs” have spawned live shows worldwide and video features. They celebrate the unusual, honor the imaginative — and spur people’s interest in science, medicine and technology.

This next item from the meeting is the kind of presentation you’d expect at these events. An environmentally friendly and low toxicity ‘nano’ flame retardant is being developed  at Texas A&M University in College Station. From the August 31, 2011 news item on physorg.com,

 In responding to the need for more environmentally friendly flame retardants, Grunlan’s [Jaime C. Grunlan] team turned to a technology termed “intumescence,” long used to fireproof exposed interior steel beams in buildings. At the first lick of a flame, an intumescent coating swells up and expands like beer foam, forming tiny bubbles in a protective barrier that insulates and shields the material below. The researchers are at Texas A&M University in College Station.

“This work is the first demonstration of a polymer-based ‘nano intumescent’,” said Grunlan. “We believe it has great potential for use as flame retardants on clothing and other materials in order to avoid some of the disadvantages of existing products.”

Now they’ve proved that it can work, the team is now working on ways to keep the flame retardant intact through the clothes  laundering process.

Presentations in the superheroes symposium with summaries of the presentations include:

  • Science outreach: Demonstrating the value of science. Jennifer Larese, NOVA Outreach Coordinator. As individuals, people learn in slightly different manners and at different rates of speed. As informal science educators, scientists have a unique opportunity to use a variety of formats, experiences and media to engage and excite their audiences. Today there are countless new electronic media tools being created, almost daily. This presentation will briefly cover science outreach as a transmedia opportunity to connect with the public.
  • Infusing moving media into instruction. Janet English, Instructor, El Toro High School, Mission Viejo, Calif. The main job for movie and TV superheroes is to save the world, and this is why many consider scientists superheroes. There are numerous ways that chemists and other scientists can affect children’s learning and help promote a love of science. The media also can play a pivotal role in students’ learning, and teachers can discuss how the media is used (or not used) in a thought-provoking way in the classroom. Scientists also can contribute to improving the mass media and how they can be role models for children.
  • Creative engagement at science cafes. John Cohen., M.D., University of Colorado School of Medicine, Department of Immunology, Denver. A Café Scientifique brings a scientist to talk directly with the public in pleasant relaxed surroundings. PowerPoint is banned to encourage dialog, rather than a lecture. There is no moderator, so the conversation finds its correct level without imposed dumbing-down. Speakers frequently say that talking at the Café Sci was one of the best experiences of their career. So do audiences and organizers.
  • Here come the Science Festivals! Kishore Hari, Director, Bay Area Science Festival. There are many ways that science festivals are raising awareness about a tremendous grassroots movement to celebrate and elevate science. Science festivals hope to rally whole communities to celebrate science as alive and local. Festivals aim to inspire youth to consider science studies and careers, and adults to cultivate a life-long interest in science and technology.
  • The Ig Nobel Prize: Never dull, never boring awards in chemistry. Marc Abrahams, Editor, Annals of Improbable Research. The Ig Nobel Prizes honor achievements that first make people laugh, then make them think. Every year since 1991, 10 new prizes have been awarded in chemistry, physics and other fields. The winners journey to Harvard University for the gala ceremony in which genuine Nobel laureates shake their hands and hand them their prizes. The “Igs” have spawned live shows worldwide and video features. They celebrate the unusual, honor the imaginative — and spur people’s interest in science, medicine and technology.