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Professor Dongman Lee Wins the 2016 Korea Internet Award
Professor Dongman Lee of KAIST’s School of Computing received the 11th Korea Internet Award in the category of personal achievement on December 13 at the Creative Economy and Innovation Center in Gyeonggi province.
Hosted by the Ministry of Science, ICT and Future Planning of Korea, the Internet Award recognizes leaders in the Internet industry and their contributions.
Since 2010, Professor Lee has conducted research on the Internet of Things (IoT) platforms, resulting in the publication of five research papers in Science Citation Index (SCI) journals, ten papers in Korean journals, 30 best papers nominations at international conferences, and the registration of eleven patents. He has also worked on the creation of an IoT ecosystem through his research on object interworking platforms that can provide diverse user-customized services in the IoT environment.
His research team built a test bed for applicable IoT platforms on the 8th floor of the IT Convergence Center on campus to implement experiments and collect various data, thereby creating a foundation to carry out research projects in this field.
Professor Lee has helped the advancement of an Internet governance system in Korea by researching Internet governance policies, holding important posts in related academic societies including the Chairman of the Korea Internet Governance Alliance (KIGA) Council, and hosting major conferences such as the Asia Pacific Regional Internet Governance Forum (APrIGF).
2016.12.20 View 7067 -
Mechanical Engineering Building on Campus Refurbished
KAIST’s Mechanical Engineering Department has finished the project to remodel its buildings and hosted an opening ceremony on December 12, 2016, which was attended by the university’s senior management and guests including President Steve Kang and Choong-Hwan Ahn, Architecture Policy Officer at the Ministry of Land, Infrastructure and Transport of Korea (MLIT).
With an investment of approximately USD 10 million, the old buildings (each consisting of seven floors and one basement) were transformed into smart, green buildings. Among the upgrades were the establishment of LED lighting systems, the replacement of the exterior walls with insulated materials, and the installation of double-glazed windows, all resulting in the improvement of the buildings’ energy efficiency. Previously, offices and lecture halls in the buildings had individual cooling and heating systems, which consumed a great deal of energy, but they were replaced with a centralized smart energy control system that monitors the operation status as well as energy consumption in real time.
With these new improvements, the Department was able to slash its energy consumption by 32%, for which it received Green Building Conversion Certification from MLIT. The ministry issues the certification to buildings that reduce their energy consumption by over 20% as a result of infrastructure upgrades. Beginning with the Mechanical Engineering buildings, KAIST will work on obtaining this certification for all of its buildings that are either under renovation or construction.
President Kang said, “We are pleased to offer our students a comfortable environment for study and research and will continue improving outdated facilities and infrastructure to make the campus safer and nicer.”
Picture 1: Ribbon-cutting ceremony for the refurbished Mechanical Engineering buildings on campus
Picture 2: Mechanical engineering buildings
2016.12.09 View 6080 -
Professor Kwon to Represent the Asia-Pacific Region of the IEEE RAS
Professor Dong-Soon Kwon of the Mechanical Engineering Department at KAIST has been reappointed to the Administrative Committee of the Institute of Electrical and Electronics Engineers (IEEE) Robotics and Automation Society (IEEE RAS). Beginning January 1, 2017, he will serve his second three-year term, which will end in 2019. In 2014, he was the first Korean appointed to the committee, representing the Asia-Pacific community of the IEEE Society.
Professor Kwon said, “I feel thankful but, at the same time, it is a great responsibility to serve the Asian research community within the Society. I hope I can contribute to the development of robotics engineering in the region and in Korea as well.”
Consisted of 18 elected members, the administrative committee manages the major activities of IEEE RAS including hosting its annual flagship meeting, the International Conference on Robotics and Automation.
The IEEE RAS fosters the advancement in the theory and practice of robotics and automation engineering and facilitates the exchange of scientific and technological knowledge that supports the maintenance of high professional standards among its members.
2016.12.06 View 8007 -
Making Graphene Using Laser-induced Phase Separation
IBS & KAIST researchers clarify how laser annealing technology can lead to the production of ultrathin nanomaterials
All our smart phones have shiny flat AMOLED (active-matrix organic light-emitting diode) displays. Behind each single pixel of these displays hides at least two silicon transistors which are mass-manufactured using laser annealing technology. While the traditional methods to make the transistors use temperature above 1,000°C, the laser technique reaches the same results at low temperatures even on plastic substrates (melting temperature below 300°C). Interestingly, a similar procedure can be used to generate crystals of graphene. Graphene is a strong and thin nano-material made of carbon, its electric and heat-conductive properties have attracted the attention of scientists worldwide.
Professor Keon Jae Lee of the Materials Science and Engineering Department at KAIST and his research group at the Center for Multidimensional Carbon Materials within the Institute for Basic Science (IBS), as well as Professor Sung-Yool Choi of the Electrical Engineering School at KAIST and his research team discovered graphene synthesis mechanism using laser-induced solid-state phase separation of single-crystal silicon carbide (SiC). This study, available in Nature Communications, clarifies how this laser technology can separate a complex compound (SiC) into its ultrathin elements of carbon and silicon.
Although several fundamental studies presented the effect of excimer lasers in transforming elemental materials like silicon, the laser interaction with more complex compounds like SiC has rarely been studied due to the complexity of compound phase transition and ultra-short processing time.
With high resolution microscope images and molecular dynamic simulations, scientists found that a single-pulse irradiation of xenon chloride excimer laser of 30 nanoseconds melts SiC, leading to the separation of a liquid SiC layer, a disordered carbon layer with graphitic domains (about 2.5 nm thick) on top surface and a polycrystalline silicon layer (about 5 nm) below carbon layer. Giving additional pulses causes the sublimation of the separated silicon, while the disordered carbon layer is transformed into a multilayer graphene.
"This research shows that the laser material interaction technology can be a powerful tool for the next generation of two dimensional nanomaterials," said Professor Lee.
Professor Choi added: "Using laser-induced phase separation of complex compounds, new types of two dimensional materials can be synthesized in the future."
High-resolution transmission electron microscopy shows that after just one laser pulse of 30 nanoseconds, the silicon carbide (SiC) substrate is melted and separates into a carbon and a silicon layer. More pulses cause the carbon layer to organize into graphene and the silicon to leave as gas.
Molecular dynamics simulates the graphene formation mechanism. The carbon layer on the top forms because the laser-induced liquid SiC (SiC (l)) is unstable.
(Press Release by Courtesy of the Institute for Basic Science (IBS))
2016.12.01 View 9946 -
Aerospace Engineering Students Win the Minister's Award
On November 11, 2016, students from KAIST’s Aerospace Engineering Department won the Minister’s Award of Trade, Industry and Energy of Korea at the 14th Research Paper Competition hosted by Korea Aerospace Industries (KAI). The award came with a cash prize of USD 1,200 as well as opportunities to visit international airshows held abroad.
The KAIST students' paper introduced a novel design concept for "a virtual-fighter-pilot system for unmanned combat aerial vehicles to enable them to engage in mass aerial combat."
This was one of the two highest honors given to contestants. A group of students from Korea Aerospace University received the other grand prize from the Minister of Land, Infrastructure and Transport of Korea.
The KAIST team consisted of two doctoral students, Hee-Min Shin and Jae-Hyun Lee, and one Master’s student, Hyun-Gi Kim. Their advisor, Professor “David” Hyunchul Shim, received the Special Achievement Award for his contribution to the paper.
KAI’s competition was established in 2003 to spur academic interest and research in aerospace engineering. Over the past 14 years, contestants have submitted 376 papers, and KAI has published 88 papers. KAI has positioned itself as the host of one of the most prestigious research paper competitions held in Korea in the area of aerospace engineering.
The Korean Society for Aeronautical and Space Sciences, the Korea Aerospace Industries Association, and the Korea Civil Aviation Development Association also sponsored the competition, with the Ministries of Trade, Industry and Energy and of Land, Infrastructure and Transport.
Professor Shim said, “This represents a great honor for our students. In recent years, research in unmanned aerial systems has increased tremendously throughout the world, and I hope KAIST will continue to inspire and innovate research in this field.”
Pictured from left to right are Hee-Min Shin, Jae-Hyun Lee, and Hyun-Gi Kim.
Pictured from right to left are Professor Hyunchul Shim, Hyun-Gi Kim, Hee-Min Shin, and Vice President Sung-Sup Chang of Korea Aerospace Industries.
2016.11.22 View 9906 -
Professor Lee Co-chairs the Global Future Councils on Biotechnology of the WEF
The World Economic Forum (WEF) established a new global network of the world’s leading experts, “The Annual Meeting of the Global Future Councils,” to explore innovative solutions for the most pressing global challenges. The Councils’ first meeting took place on November 13-14, 2016, in Dubai, the United Arab Emirates (UAE). Some 25 nations joined as member states. The Councils have 35 committees.
Over 700 global leaders in business, government, civil society and academia gathered at the inaugural meeting to “develop ideas and strategies to prepare the world for the Fourth Industrial Revolution, with topics including smart cities, robotics, and the future of mobility,” according to a statement issued by the WEF.
Distinguished Professor Sang Yup Lee of Chemical and Biomolecular Engineering at KAIST was appointed to co-chair one of the Councils' committees, The Annual Meeting of the Global Future Councils on Biotechnology, for two years. The other chairperson is Dr. Feng Zhang, a professor of Biomedical Engineering at the Massachusetts Institute of Technology (MIT), who played a critical role in the development of optogenetics and CRISPR technologies.
The Biotechnology Committee consists of 24 globally recognized professionals in life sciences, law, ethics and policy including Thomas Connelly, the executive director of the American Chemical Society, Tina Fano, the executive vice president of Novozymes, and Mostafa Ronaghi, the chief technology officer of Illumina.
Professor Lee also serves as a committee member of The Annual Meeting of the Global Future Councils on the Fourth Industrial Revolution.
“Life sciences and engineering will receive more attention as a key element of the Fourth Industrial Revolution that the global society as a whole has been experiencing now. Together with thought leaders gathered worldwide, I will join the international community’s concerted efforts to address issues of importance that impact greatly on the future of humanity,” Professor Lee said.
In addition, Professor Lee received the James E. Bailey Award 2016 from The Society for Biological Engineering on November 15, 2016. He is the first Asian researcher to be recognized for his contributions to the field of biotechnology.
2016.11.15 View 8022 -
2016 KAIST EEWS Workshop
The Energy, Environment, Water and Sustainability (EEWS) Graduate School of KAIST hosted a workshop entitled “Progress and Perspectives of Energy Science and Technology” on October 20, 2016. The workshop took place at the Fusion Hall of the KAIST Institute on campus.
About 400 experts in energy science and engineering participated in the event. Eight globally recognized scientists introduced the latest research trends in nanomaterials, energy theory, catalysts, and photocatalysts and led discussions on the current status and prospects of EEWS.
Professors Yi Cui of Stanford University, an expert in nanomaterials, and William A. Goddard of California Institute of Technology presented their research experiments on materials design and recent results on the direction of theory under the topics of energy and environment.
Dr. Miquel Salmeron, a former head of the Material Science Division of Lawrence Berkeley National Laboratory, and Professor Yuichi Ikuhara of Tokyo University introduced their analysis of catalysts and energy matters at an atomic scale.
Professor Sukbok Chang of the Chemistry Department at KAIST, a deputy editor of ACS Catalysis and the head of the Center for Catalytic Hydrocarbon Functionalizations at the Institute of Basic Science, and Professor Yang-Kook Sun of Energy Engineering at Hanyang University, who is also a deputy editor of ACS Energy Letters, presented their latest research results on new catalytic reaction development and energy storage.
The workshop consisted of three sections which addressed the design of energy and environment materials; analysis of energy and catalytic materials; and energy conversion and catalysts.
The EEWS Graduate School was established in 2008 with the sponsorship of the Korean government’s World Class University (WCU) project to support science education in Korea. Professor J. Fraser Stoddart, the winner of the 2016 Nobel Prize in Chemistry, was previously worked at the KAIST EEWS Graduate School as a WCU visiting professor for two years, from 2011 to 2013. Professor Ali Coskun, who was a postdoctoral researcher in the laboratory of Professor Stoddart, now teaches and conducts research as a full-time professor at the graduate school.
Dean Yousung Jung of the EEWS Graduate School said:
“This workshop has provided us with a meaningful opportunity to engage in discussions on energy science and technology with world-class scholars from all around the world. It is also a good venue for our graduate school to share with them what we have been doing in research and education.”
2016.10.20 View 10816 -
J. Fraser Stoddart, a Former Visiting Professor at KAIST, Wins the 2016 Nobel Prize in Chemistry
J. Fraser Stoddart, who is Northwestern University’s Board of Trustees Professor of Chemistry and head of the Stoddart Mechanostereochemistry Group, received the 2016 Nobel Prize in Chemistry. He shares it with Professor Jean-Pierre Sauvage of the University of Strasbourg in France and Professor Bernard Feringa of the University of Groningen in the Netherlands.
Professor Stoddart’s relationship with KAIST dates to his term as a visiting professor from 2011 to 2013 at the Environment, Energy, Water and Sustainability (EEWS) Graduate School. The Nobel Committee awarded the prize to Professor Stoddart in recognition of his pioneering work on artificial molecular machines, a.k.a., nanomachines.
A molecular machine is an assembly of a discrete number of molecular components designed to perform machine-like movements as the result of appropriate external stimuli. Like their counterparts in the macroscopic world, molecular machines control mechanical movements and rotations in response to an energy input such as chemical reactions, light, or temperature. The most complex molecular machines, for example, are proteins in cells. Chemists have attempted to imitate these structures for potential applications including smart nanomedicines to track diseases such as cancer cells and deliver drugs to fight them. Other applications include next-generation miniature semiconductor chips, sensors, energy storage, space exploration, and armaments.
In 1991, Professor Stoddart developed artificial molecular machines based on a rotaxane. A rotaxane is a mechanically-interlocked molecular architecture in which a dumbbell-shaped molecule is encircled by a molecular ring called a macrocycle. He presented important research on the production of rotaxanes and demonstrated that a macrocycle could move along or rotate freely around the axle, a dumbbell-shaped molecule.
Professor Stoddart is also an expert in molecular electronics using molecules on the nanoscale as switches in computers and other electronic devices. In 2007, he created a large-scale ultra-dense memory device with reconfigurable molecular switches, the size of white blood cells but capable of storing information. This was a significant achievement towards the development of molecular computers that are much smaller and more powerful compared to today’s silicon-based computers.
KAIST has enjoyed a strong relationship with Professor Stoddart since he served as a visiting professor at the EEWS Graduate School from 2011 to 2013. The graduate school invited him to participate in the Korean government’s science and education program to foster world-class universities in the nation. At KAIST, he taught a course entitled “Nanomachines at the Scale of Molecules.” He also collaborated with Korean researchers on various projects including the publication of a joint research paper, “A Radically Configurable Six-State Compound,” in Science (January 25, 2013) with Professor Jang Wook Choi from the EEWS Graduate School and researchers from the United States, the United Kingdom, and Saudi Arabia.
Two doctors with KAIST ties have links to Professor Stoddart as well. In 2012, Dr. Ali Coskun, who worked with him as a postdoctoral research associate at Northwestern University, became an associate professor at the EEWS Graduate School where he conducts research on secondary batteries and gas storage with artificial molecular machines. Dr. Dong Jun Kim, a KAIST graduate, has been working at the Stoddart Mechanostereochemistry Group as a postdoctoral fellow since 2015.
Picture 1: Synthesis of a Rotaxane Described in the Journal of the American Chemical Society (JACS) in 1991
Picture 2: Professor J. Fraser Stoddart Giving a Presentation at a Workshop Hosted by the EEWS Graduate School at KAIST in 2011
2016.10.13 View 7988 -
Extremely Thin and Highly Flexible Graphene-Based Thermoacoustic Speakers
A joint research team led by Professors Jung-Woo Choi and Byung Jin Cho of the School of Electrical Engineering and Professor Sang Ouk Kim of the Material Science and Engineering Department, all on the faculty of the Korea Advanced Institute of Science and Technology (KAIST), has developed a simpler way to mass-produce ultra-thin graphene thermosacoustic speakers.
Their research results were published online on August 17, 2016 in a journal called Applied Materials & Interfaces. The IEEE Spectrum, a monthly magazine published by the Institute of Electrical and Electronics Engineers, reported on the research on September 9, 2016, in an article titled, “Graphene Enables Flat Speakers for Mobile Audio Systems.” The American Chemical Society also drew attention to the team’s work in its article dated September 7, 2016, “Bringing Graphene Speakers to the Mobile Market.”
Thermoacoustic speakers generate sound waves from temperature fluctuations by rapidly heating and cooling conducting materials. Unlike conventional voice-coil speakers, thermoacoustic speakers do not rely on vibrations to produce sound, and thus do not need bulky acoustic boxes to keep complicated mechanical parts for sound production. They also generate good quality sound in all directions, enabling them to be placed on any surface including curved ones without canceling out sounds generated from opposite sides.
Based on a two-step, template-free fabrication method that involved freeze-drying a solution of graphene oxide flakes and the reduction/doping of oxidized graphene to improve electrical properties, the research team produced a N-doped, three-dimensional (3D), reduced graphene oxide aerogel (N-rGOA) with a porous macroscopic structure that permitted easy modulation for many potential applications.
Using 3D graphene aerogels, the team succeeded in fabricating an array of loudspeakers that were able to withstand over 40 W input power and that showed excellent sound pressure level (SPL), comparable to those of previously reported 2D and 3D graphene loudspeakers.
Choong Sun Kim, the lead author of the research paper and a doctoral student in the School of Electrical Engineering at KAIST, said:
“Thermoacoustic speakers have a higher efficiency when conducting materials have a smaller heat capacity. Nanomaterials such as graphene are an ideal candidate for conductors, but they require a substrate to support their extremely thinness. The substrate’s tendency to lose heat lowers the speakers’ efficiency. Here, we developed 3D graphene aerogels without a substrate by using a simple two-step process. With graphene aerogels, we have fabricated an array of loudspeakers that demonstrated stable performance. This is a practical technology that will enable mass-production of thermosacoustic speakers including on mobile platforms.”
The research paper is entitled “Application of N-Doped Three-Dimensional Reduced Graphene Oxide Aerogel to Thin Film Loudspeaker.” (DOI: 10.1021/acsami.6b03618)
Figure 1: A Thermoacoustic Loudspeaker Consisted of an Array of 16 3D Graphene Aerogels
Figure 2: Two-step Fabrication Process of 3D Reduced Graphene Oxide Aerogel Using Freeze-Drying and Reduction/Doping
Figure 3: X-ray Photoelectron Spectroscopy Graph of the 3D Reduced Graphene Oxide Aerogel and Its Scanning Electron Microscope Image
2016.10.05 View 11840 -
KAIST Team Develops Semi-Transparent Solar Cells with Thermal Mirror Capability
A research team led by KAIST and Sungkyunkwan University professors has created semi-transparent perovskite solar cells that demonstrate high-power conversion efficiency and transmit visible light while blocking infrared light, making them great candidates for solar windows.
Modern architects prefer to build exteriors designed with glass mainly from artistic or cost perspectives. Scientists, however, go one step further and see opportunities from its potential ability to harness solar energy. Researchers have thus explored ways to make solar cells transparent or semi-transparent as a substitute material for glass, but this has proven to be a challenging task because solar cells need to absorb sunlight to generate electricity, and when they are transparent, it reduces their energy efficiency.
Typical solar cells today are made of crystalline silicon, but it is difficult to make them translucent. Semi-transparent solar cells under development use, for example, organic or dye-sensitized materials, but compared to crystalline silicon-based cells, their power-conversion efficiencies are relatively low. Perovskites are hybrid organic-inorganic halide-based photovoltaic materials, which are cheap to produce and easy to manufacture. They have recently received much attention as the efficiency of perovskite solar cells has rapidly increased to the level of silicon technologies in the past few years.
Using perovskites, a Korean research team led by Professor Seunghyup Yoo of the Electrical Engineering School at KAIST and Professor Nam-Gyu Park of the Chemical Engineering School at Sungkyunkwan University developed a semi-transparent solar cell that is highly efficient and, additionally, functions very effectively as a thermal-mirror.
The team has developed a top transparent electrode (TTE) that works well with perovskite solar cells. In most cases, a key to success in realizing semi-transparent solar cells is to find a TTE that is compatible with a given photoactive material system, which is also the case for perovskite solar cells. The proposed TTE is based on a multilayer stack consisting of a metal film sandwiched between a high refractive-index (high-index) layer and an interfacial buffer layer. This TTE, placed as a top-most layer, can be prepared without damaging ingredients used in perovskite solar cells. Unlike conventional transparent electrodes focusing only on transmitting visible light, the proposed TTE plays the dual role of passing through visible light while reflecting infrared rays. The semi-transparent solar cells made with the proposed TTEs exhibited average power conversion efficiency as high as 13.3% with 85.5% infrared rejection.
The team believes that if the semi-transparent perovskite solar cells are scaled up for practical applications, they can be used in solar windows for buildings and automobiles, which not only generate electrical energy but also enable the smart heat management for indoor environments, thereby utilizing solar energy more efficiently and effectively.
This result was published as a cover article in the July 20, 2016 issue of Advanced Energy Materials. The research paper is entitled “Empowering Semi-transparent Solar Cells with Thermal-mirror Functionality.” (DOI: 10.1002/aenm.201502466)
The team designed the transparent electrode (TE) stack in three layers: A thin-film of silver (Ag) is placed in between the bottom interfacial layer of molybdenum trioxide (MoO3) and the top high-index dielectric layer of zinc sulfide (ZnS). Such a tri-layer approach has been known as a means to increase the overall visible-light transmittance of metallic thin films via index matching technique, which is essentially the same technique used for anti-reflection coating of glasses except that the present case involves a metallic layer.
Traditionally, when a TE is based on a metal film, such as Ag, the film should be extremely thin, e.g., 7-12 nanometers (nm), to obtain transparency and, accordingly, to transmit visible light. However, the team took a different approach in this research. They made the Ag TE two or three times thicker (12-24 nm) than conventional metal films and, as a result, it reflected more infrared light. The high refractive index of the ZnS layer plays an essential role in keeping the visible light transmittance of the proposed TTE high even with the relatively thick Ag film when its thickness is carefully optimized for maximal destructive interference, leading to low reflectance (and thus high transmittance) within its visible light range.
The team confirmed the semi-transparent perovskite solar cell’s thermal-mirror function through an experiment in which a halogen lamp illuminated an object for five minutes through three mediums: a window of bare glass, automotive tinting film, and the proposed semi-transparent perovskite solar cell. An infrared (IR) camera took thermal images of the object as well as that of each window’s surface. The object’s temperature, when exposed through the glass window, rose to 36.8 Celsius degrees whereas both the tinting film and the cell allowed the object to remain below 27 Celsius degrees. The tinting film absorbs light to block solar energy, so the film’s surface became hot as it was continuously exposed to the lamp light, but the proposed semi-transparent solar cell stayed cool since it rejects solar heat energy by reflection, rather than by absorption. The total solar energy rejection (TSER) of the proposed cell was as high as 89.6%.
Professor Yoo of KAIST said, “The major contributions of this work are to find transparent electrode technology suitable for translucent perovskite cells and to provide a design approach to fully harness the potential it can further deliver as a heat mirror in addition to its main role as an electrode. The present work can be further fine-tuned to include colored solar cells and to incorporate flexible or rollable form factors, as they will allow for greater design freedom and thus offer more opportunities for them to be integrated into real-world objects and structures such as cars, buildings, and houses.”
The lead authors are Hoyeon Kim and Jaewon Ha, both Ph.D. candidates in the School of Electrical Engineering at KAIST, and Hui-Seon Kim, a student in the School of Chemical Engineering at Sungkyunkwan University. This research was supported mainly by the Climate Change Research Hub Program of KAIST.
Picture 1: Semi-transparent Perovskite Solar Cell
This picture shows a prototype of a semi-transparent perovskite solar cell with thermal-mirror functionality.
Picture 2: A Heat Rejection Performance Comparison Experiment
This picture presents thermal images taken by an infrared camera for comparing the heat rejection performance of bare glass, automotive tinting film, and a semi-transparent perovskite solar cell after being illuminated by a halogen lamp for five minutes.
2016.08.02 View 11435 -
KAIST Develops Transparent Oxide Thin-Film Transistors
With the advent of the Internet of Things (IoT) era, strong demand has grown for wearable and transparent displays that can be applied to various fields such as augmented reality (AR) and skin-like thin flexible devices. However, previous flexible transparent displays have posed real challenges to overcome, which are, among others, poor transparency and low electrical performance. To improve the transparency and performance, past research efforts have tried to use inorganic-based electronics, but the fundamental thermal instabilities of plastic substrates have hampered the high temperature process, an essential step necessary for the fabrication of high performance electronic devices.
As a solution to this problem, a research team led by Professors Keon Jae Lee and Sang-Hee Ko Park of the Department of Materials Science and Engineering at the KAIST has developed ultrathin and transparent oxide thin-film transistors (TFT) for an active-matrix backplane of a flexible display by using the inorganic-based laser lift-off (ILLO) method. Professor Lee’s team previously demonstrated the ILLO technology for energy-harvesting (Advanced Materials, February 12, 2014) and flexible memory (Advanced Materials, September 8, 2014) devices.
The research team fabricated a high-performance oxide TFT array on top of a sacrificial laser-reactive substrate. After laser irradiation from the backside of the substrate, only the oxide TFT arrays were separated from the sacrificial substrate as a result of reaction between laser and laser-reactive layer, and then subsequently transferred onto ultrathin plastics ( thickness). Finally, the transferred ultrathin-oxide driving circuit for the flexible display was attached conformally to the surface of human skin to demonstrate the possibility of the wearable application. The attached oxide TFTs showed high optical transparency of 83% and mobility of even under several cycles of severe bending tests.
Professor Lee said, “By using our ILLO process, the technological barriers for high performance transparent flexible displays have been overcome at a relatively low cost by removing expensive polyimide substrates. Moreover, the high-quality oxide semiconductor can be easily transferred onto skin-like or any flexible substrate for wearable application.”
These research results, entitled “Skin-Like Oxide Thin-Film Transistors for Transparent Displays,”
(http://onlinelibrary.wiley.com/doi/10.1002/adfm.201601296/abstract) were the lead article published in the July 2016 online issue of Wiley’s Advanced Functional Materials.
###
References
[1] Advanced Materials, February 12, 2014, Highly-efficient, Flexible Piezoelectric PZT Thin Film Nanogenerator on Plastic Substrates
(http://onlinelibrary.wiley.com/doi/10.1002/adma.201305659/abstract)
[2] Advanced Materials, September 8, 2014, Flexible Crossbar-structured Resistive Memory Arrays on Plastic Substartes via Inorganic-based Laser Lift-off
(http://onlinelibrary.wiley.com/doi/10.1002/adma.201402472/abstract)
Picture 1: A Schamatic Image of Ultrathin, Flexible, and Transparent Oxide Thin-film Transistors
This image shows ultrathin, flexible, and transparent oxide thin-film transistors produced via the ILLO process.
Picture 2: Application of Uultrathin, Flexible, and Transparent Oxide Thin-film Transistors
This picture shows ultrathin, flexible, and transparent oxide thin-film transistors attached to a jumper sleeve and human skin.
2016.08.01 View 11599 -
Unveiling the Distinctive Features of Industrial Microorganism
KAIST researchers have sequenced the whole genome of Clostridium tyrobutyricum, which has a higher tolerance to toxic chemicals, such as 1-butanol, compared to other clostridial bacterial strains.
Clostridium tyrobutyricum, a Gram-positive, anaerobic spore-forming bacterium, is considered a promising industrial host strain for the production of various chemicals including butyric acid which has many applications in different industries such as a precursor to biofuels. Despite such potential, C. tyrobutyricum has received little attention, mainly due to a limited understanding of its genotypic and metabolic characteristics at the genome level.
A Korean research team headed by Distinguished Professor Sang Yup Lee of the Chemical and Biomolecular Engineering Department at the Korea Advanced Institute of Science and Technology (KAIST) deciphered the genome sequence of C. tyrobutyricum and its proteome profiles during the course of batch fermentation. As a result, the research team learned that the bacterium is not only capable of producing a large amount of butyric acid but also can tolerate toxic compounds such as 1-butanol. The research results were published in mBio on June 14, 2016.
The team adopted a genoproteomic approach, combining genomics and proteomics, to investigate the metabolic features of C. tyrobutyricum. Unlike Clostridium acetobutylicum, the most widely used organism for 1-butanol production, C. tyrobutyricum has a novel butyrate-producing pathway and various mechanisms for energy conservation under anaerobic conditions. The expression of various metabolic genes, including those involved in butyrate formation, was analyzed using the “shotgun” proteome approach.
To date, the bio-based production of 1-butanol, a next-generation biofuel, has relied on several clostridial hosts including C. acetobutylicum and C. beijerinckii. However, these organisms have a low tolerance against 1-butanol even though they are naturally capable of producing it. C. tyrobutyricum cannot produce 1-butanol itself, but has a higher 1-butanol-tolerance and rapid uptake of monosaccharides, compared to those two species.
The team identified most of the genes involved in the central metabolism of C. tyrobutyricum from the whole-genome and shotgun proteome data, and this study will accelerate the bacterium’s engineering to produce useful chemicals including butyric acid and 1-butanol, replacing traditional bacterial hosts.
Professor Lee said,
“The unique metabolic features and energy conservation mechanisms of C. tyrobutyricum can be employed in the various microbial hosts we have previously developed to further improve their productivity and yield. Moreover, findings on C. tyrobutyricum revealed by this study will be the first step to directly engineer this bacterium.”
Director Jin-Woo Kim at the Platform Technology Division of the Ministry of Science, ICT and Future Planning of Korea, who oversees the Technology Development Program to Solve Climate Change, said,
“Over the years, Professor Lee’s team has researched the development of a bio-refinery system to produce natural and non-natural chemicals with the systems metabolic engineering of microorganisms. They were able to design strategies for the development of diverse industrial microbial strains to produce useful chemicals from inedible biomass-based carbon dioxide fixation. We believe the efficient production of butyric acid using a metabolic engineering approach will play an important role in the establishment of a bioprocess for chemical production.”
The title of the research paper is “Deciphering Clostridium tyrobutyricum Metabolism Based on the Who-Genome Sequence and Proteome Analyses.” (DOI: 10.1128/mBio.00743-16)
The lead authors are Joungmin Lee, a post-doctoral fellow in the BioProcess Research Center at KAIST, currently working in CJ CheilJedang Research Institute; Yu-Sin Jang, a research fellow in the BioProcess Research Center at KAIST, currently working at Gyeongsang National University as an assistant professor; and Mee-Jung Han, an assistant professor in the Environmental Engineering and Energy Department at Dongyang University. Jin Young Kim, a senior researcher at the Korea Basic Science Institute, also participated in the research.
This research was supported by the Technology Development Program to Solve Climate Change’s research project entitled “Systems Metabolic Engineering for Biorefineries” from the Ministry of Science, ICT and Future Planning through the National Research Foundation of Korea (NRF-2012M1A2A2026556).
Schematic Diagram of C. tyrobutyricum’s Genome Sequence and Its Proteome Profiles
The picture below shows the complete genome sequence, global protein expression profiles, and the genome-based metabolic characteristics during batch fermentation of C. tyrobutyricum.
2016.06.20 View 9484