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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.
Next-Generation Holographic Microscope for 3D Live Cell Imaging
KAIST researchers have developed a revolutionary bio-medical imaging tool, the HT-1, to view and analyze cells, which is commercially available. Professor YongKeun Park of the Physics Department at KAIST and his research team have developed a powerful method for 3D imaging of live cells without staining. The researchers announced the launch of their new microscopic tool, the holotomography (HT)-1, to the global marketplace through a Korean start-up that Professor Park co-founded, TomoCube (www.tomocube.com). Professor Park is a leading researcher in the field of biophotonics and has dedicated much of his research career to working on digital holographic microscopy technology. He collaborated with TomoCube’s R&D team to develop a state-of-the-art, 2D/3D/4D holographic microscope that would allow a real-time label-free visualization of biological cells and tissues. The HT is an optical analogy of X-ray computed tomography (CT). Both X-ray CT and HT share the same physical principle—the inverse of wave scattering. The difference is that HT uses laser illumination whereas X-ray CT uses X-ray beams. From the measurement of multiple 2D holograms of a cell, coupled with various angles of laser illuminations, the 3D refractive index (RI) distribution of the cell can be reconstructed. The reconstructed 3D RI map provides structural and chemical information of the cell including mass, morphology, protein concentration, and dynamics of the cellular membrane. The HT enables users to quantitatively and non-invasively investigate the intrinsic properties of biological cells, for example, dry mass and protein concentration. Some of the research team’s breakthroughs that have leveraged HT’s unique and special capabilities can be found in several recent publications, including a lead article on the simultaneous 3D visualization and position tracking of optically trapped particles which was published in Optica on April 20, 2015. Current fluorescence confocal microscopy techniques require the use of exogenous labeling agents to render high-contrast molecular information. Therefore, drawbacks include possible photo-bleaching, photo-toxicity, and interference with normal molecular activities. Immune or stem cells that need to be reinjected into the body are considered particularly difficult to employ with fluorescence microscopy. “As one of the two currently available, high-resolution tomographic microscopes in the world, I believe that the HT-1 is the best in class regarding specifications and functionality. Users can see 3D/4D live images of cells, without fixing, coating or staining cells. Sample preparation times are reduced from a few days or hours to just a few minutes,” said Professor Park. Two Korean hospitals, Seoul National University Hospital in Bundang and Boramae Hospital in Seoul, are using this microscope currently. The research team has also introduced the HT-1 at the Photonics West Exhibition 2016 that took place on February 16-18 in San Francisco, USA. Professor Park added, “Our technology has set a new paradigm for cell observation under a microscope. I expect that this tomographic microscopy will be more widely used in future in various areas of pharmaceuticals, neuroscience, immunology, hematology, and cell biology.” Figure 1: HT-1 and Its Specifications Figure 2: 3D Images of Representative Biological Cells Taken with the HT-1
Professor Joonho Choe Appointed as the President of the KSMCB
Professor Joonho Choe of the Biological Sciences Department at KAIST has been elected the 25th president of Korean Society for Molecular and Cellular Biology (KSMCB). His presidency will last one year, beginning on January 1, 2016. Established in 1989, the Society has served as the largest academic gathering in the field of life sciences, holding an international conference every fall. It has more than 12,400 fellows. Professor Choe served as the vice president of KSMC as well as the editor of its journal, Molecules and Cells. He said, “The 2016 International Conference of the KSMCB will take place on October 12-14, 2016 at the COEX Convention and Exhibition Hall in Seoul. This year, we are preparing 20 symposiums and will invite four international renowned keynote speakers in the field including a Nobel Laureate. We hope many people, students and young researchers in particular, from academia and industry will join the conference.” Professor Choe received his doctoral degree from the University of California, Los Angeles (UCLA) after graduating from Seoul National University with his bachelor and master’s degrees.
KAIST's Top 10 Contributions to Korea and the World
Established in 1971, the Korea Advanced Institute of Science and Technology (KAIST) started off as a relatively modest graduate school in a few disciplines in science and technology, but has gradually expanded into a full-fledged research university over the years. From the beginning, KAIST was intended to offer an elite science education, setting it apart from other universities in Korea. A majority of its graduates have contributed to the development of, what the world now praises, Korean industry and economy, and have led the Korean scientific community for several decades. The university has also advanced the frontiers of knowledge, conducting the lion’s share of the nation’s private research and development in basic and applied science, leading to innovations and technologies essential to the growth of today’s Korea. As it establishes international benchmarks of success, KAIST has acquired a global reputation for delivering the highest level of science and engineering education, while performing cutting-edge research and serving as a crucial driver to generate new knowledge and innovation beneficial not only to Korea but also to the world. The university has consistently ranked in the top 100 research universities for over more than a decade, according to the world university rankings published by international ranking institutions for higher education, among others, Quacquarelli Symonds and the Times Higher Education. KAIST will mark its 45th anniversary next year. It plans to celebrate the anniversary, and here are some of the reasons why: KAIST’s Win at the DARPA Robotics Challenge (DRC) 2015 Team KAIST, consisted of 29 members (students and researchers) led by Professors Jun-Ho Oh of the Mechanical Engineering Department and In-So Kweon of the Electrical Engineering Department, won the international humanoid robotics competition hosted by the United States (US) Defense Advanced Research Projects Agency (DARPA). Upon completion of the first and second competitions, the finals were held on June 5-6, 2015, at the Fairplex in Pomona, California. DARPA hosted the event to spur the development of humanoid robots to assist rescue and relief efforts in dangerous environments such as the Fukushima Daiichi nuclear incident in 2011. With 24 international teams participating in the finals from the US, Japan, Germany, China, Italy, and Korea, Team KAIST’s humanoid robot, DRC-HUBO, completed all eight tasks in 44 minutes and 28 seconds, six minutes earlier than the runner-up, and almost eleven minutes earlier than the third-place team, walking away with the grand prize of USD 2 million. Hitting a Grand Slam to Win Major International Design Awards Professor Sang-Min Bae of the Industrial Design Department achieved a grand slam in international design awards with his work HEARTea, an interactive tumbler, winning four major design competitions in the world: the iF Design Award, the International Design Excellence Awards, the Red Dot Design Award, and the Good Design Award. Released in 2010, HEARTea swept prizes from the four awards which were held during the period of the year 2010-2011. The tumbler displays the temperature of liquid contained inside in three degrees (cool, warm, and hot) by showing different colored lights on the surface of the tumbler based on the liquid temperature (see picture below). In 2015, Professor Bae and his research team won three awards from the 2015 Red Dot Design Award: the Best of the Best Award and two Red Dot Design Concept Awards. The team received the Best of the Best Award, the most prestigious award among the Red Dot Design awards, for Boxchool, a modular classroom built on shipping containers, which offers underprivileged children better opportunities for learning. With greater mobility, Boxchool can be easily installed in any setting, including remote areas where children do not have access to regular school facilities. Glass Fabric Thermoelectric Generator, the Grand Prize Winner at the Netexplo Forum 2015 Professor Byung-Jin Cho of the Electrical Engineering Department received the grand prize at the Netexplo Forum 2015 held in partnership with the United Nations Educational, Scientific, and Cultural Organization (UNESCO) on February 4-5, 2015, at the UNESCO House in Paris. Established in 2007, the Netexplo Forum is an annual international conference hosted by the Netexplo Observatory, a non-profit organization sponsored by the French Senate and the French Ministry for the Digital Economy, which studies the impact of digital technology on society and business. Each year, the Netexplo Forum highlights major trends in digital technology and innovation worldwide and lists the top ten most promising technologies that it considers will greatly impact the world. Among the list for this year, Professor Cho’s glass fabric-based thermoelectric (TE) generator received the grand prize. Using a screen-printing technique, Professor Cho printed TE liquid materials onto a glass fabric to generate electricity through the thermoelectric effect, that is, by generating electricity from temperature difference. Since the glass fabric is light and flexible, this technology is expected to have a wide range of applications in wearable computers and devices. Charging on the Go: Online Electric Vehicle System KAIST’s Online Electric Vehicle (OLEV) is a system that charges electric vehicles while stationary or driving, thus removing the need to stop for charges. Developed by Professor Dong-Ho Cho of the Electrical Engineering Department and his research team, OLEV receives power wirelessly through a new application called “Shaped Magnetic Field in Resonance technology (SMFIR).” Electrical cables buried underneath roads create magnetic fields, and a receiving device installed underneath the electric vehicle collects the fields and converts them into electricity. Time, a US weekly magazine, listed OLEV as one of the 50 Greatest Inventions of the Year 2010 in its November 22nd issue. Since 2012, several OLEV buses have been operating daily to provide citizens with transportation in cities such as Yeosu, Gumi, and Sejong in Korea. In April 2015, Professor Cho signed a memorandum of understanding with the city government of Medellín, the second largest city in Colombia, to provide two OLEV buses for inner-city transportation services. The research team also developed OLEV for a high capacity transit system including trams and high-speed trains, successfully showcasing 60 kHz of power transferred wirelessly to trams and trains in 2013 and 2014, respectively. Pioneer in the Development of Functional Mesoporous Materials and Zeolites On September 25, 2014, Thomson Reuters announced the “2014 Citation Laureates,” a list of candidates considered likely to win the Nobel Prize in the fields of physics, chemistry, physiology or medicine, and economics. Distinguished Professor Ryong Ryoo of the Department of Chemistry was named the 2014 Thomson Reuters Citation Laureates in Chemistry in recognition of his significant contribution to the advancement of designing functional mesoporous materials. He is the first Korean scientist to make the list. Professor Ryoo has pioneered the field of functional mesoporous materials and zeolites which are widely used as catalysts and sorbents. In 1999, he developed a nanocasting method, and with the technique, was able to synthesize ordered mesoporous carbon materials, for the first time in the world. Today, ordered mesoporous carbon materials have widespread applications in many areas such as adsorbents, catalysts and supports, gas-storage hosts, and electrode materials. Since 2006, using zeolite frameworks, Professor Ryoo has led the development of new methods to synthesize mesoporous materials whose molecules are designed to have a hierarchical structure of microspores and mesopores. He has published 255 research papers in renowned academic journals including Nature and Science. In December 2011, Science highlighted his research as one of the top ten breakthroughs in the year of 2011 in an article entitled “Directing Zeolite Structures into Hierarchically Nanoporous Architectures.” Professor Ryoo received numerous awards and honors including the World’s Top 100 Chemists over the Past 11 Years (2000-2010) by UNESCO and IUPAC (International Union of Pure and Applied Chemistry), the Breck Award by International Zeolite Association, and the Ho-Am prize in Science. The Launch of Korea’s First Satellites into Space Founded in 1989, the Satellite Technology Research Center (SaTReC) at KAIST has led the development of a series of Korean-made satellites over the past 26 years. The first satellite, the Korea Institute of Technology Satellite-1 (KITSAT-1), was launched on August 11, 1992, at the Guiana Space Center in Kourou, French Guiana. KITSAT-1 was designed in collaboration with a British university, the University of Surrey in Guildford. The success of KITSAT-1 sparked nation-wide interest in the development of space technology and led to the subsequent launches of 18 satellites and three carrier rockets such as KITSAT-2 and 3 (meteorological satellites); KSR-1, 2, and 3 (carrier rockets); KOREASAT-1, 2, 3, 5, and 6 (communication satellites); KOMPSAT-1, 2, 3, and 5 (multipurpose satellites); STSAT-1, 2C, and 3 (scientific satellites); and COMS-1 (navigation satellite). The latest scientific satellite, STSAT-3, and an earth observation satellite, KOMPSAT-3A, were launched in 2013 and 2015, respectively. The STSAT-2C, exclusively developed by SaTReC, was launched in January 2013 and transmitted data on the observation of space environments to the ground station located on KAIST’s campus for 14 months. The STSAT-2C was the first satellite developed solely with Korean technology. On June 30, 2009, the Korean government also established a spaceport in South Jeolla’s Goheung County, the Naro Space Center to launch satellites and spacecraft. KAIST: Major Feeder for Startups in Korea As seen in its core values of promoting creativity and a challenging spirit, KAIST has always encouraged startups and technology transfers led by university members including students and faculty. In the past four years from 2011 to 2014, students and faculty members have created 104 startups based on technology innovation and research outcomes, with an average of 26 new companies started per year. This is the highest number of university-led startups in Korea. As of 2013, KAIST graduates founded a total of 1,245 companies, generating approximately USD 1.5 billion sales and creating 34,000 jobs. KAIST has provided a variety of programs and facilities to build a startup-friendly campus culture and support student- and faculty-led entrepreneurship, for example, the End-Run Policy, Startup KAIST Studio, the Institute of Startup and Entrepreneurship, and the Startup Incubation Center. In particular, KAIST Idea Factory, a startup laboratory established last year, where students play around with ideas by conducting new experiments or building test products, created 3-D printers this year, producing 20 prototypes and filing four pending patents. Recently, KAIST has registered four proprietary standard patents with MPEG (Moving Picture Experts Group)-LA’s HEVC (High Efficiency Video Coding) Patent Portfolio License, which provides access to essential patent rights for the HEVC digital video coding standard. KAIST expects to acquire more than 50 proprietary standard patents within two years, generating close to UDS 1 million in income. The Number of KAIST Doctoral Graduates Reaches Over 10,000 Since the establishment of KAIST forty-four years ago, more than ten thousand alumni have received their doctorates. The university’s 2015 Commencement ceremony took place on February 13, 2015, at the Sports Complex on campus, awarding Dr. Sun-Mi Cho of the Department of Biological Sciences the 10,000th doctoral degree. She also received her Bachelor’s and Master’s degrees from KAIST. In 1978, KAIST had only two doctoral graduates, but since 1987, there have been more than one hundred graduates each year, two hundred since 1994, and four hundred since 2000. In 2015 alone, 522 doctoral students graduated. One of the first doctoral graduates, Dr. Dong-Yol Yang (Class of 1978 in the Mechanical Engineering Department) became a professor in the same department of KAIST. In the early 1970s, many Koreans preferred to go abroad for Ph.D. degrees, but this changed when KAIST began to select candidates for master’s degrees in 1973, and doctoral degrees in 1975. Talented Korean students began to work in KAIST laboratories, and its graduates were known for their knowledge and skills. Now, KAIST receives many applications from talented foreign students as well. At the 2015 Commencement, KAIST conferred 522 Doctoral, 1,241 Master’s, and 915 Bachelor of Science degrees. Since its inception in 1971, KAIST has granted 10,403 doctoral degrees, 26,402 master’s degrees, and 51,412 bachelor’s degrees. Fostering a New Learning Model: The Education 3.0 Program KAIST undertook a bold initiative to improve its education system that would address more effectively the needs of today’s higher education to foster talents with creative and critical thinking skills. It introduced a new pedagogical model, the Education 3.0 program, to the campus in the spring of 2012, which was then an extremely rare movement taken by universities around the world. The Education 3.0 program incorporates flipped learning and smart classrooms. This means there are no formal lectures while in-class time is devoted to problem solving, exercises, projects, or discussions. The program provided students with greater opportunity to control their learning and interact more with professors and peers. Originally started with three general courses in physics, chemistry, and biology, the Education 3.0 is now offered in 50-60 courses per semester. In 2013 alone, approximately 2,000 KAIST students took the Education 3.0 courses. The university has also developed and implemented an e-Learning system to provide online courses, as well as participated in the Massive Open Online Course (MOOC). Partnering with Coursera since 2013, KAIST has offered three MOOCs in engineering and business management to the global community. Leading the efforts to create Korean MOOCs (K-MOOCs), KAIST agreed with other Korean universities in October 2015 to create online courses in basic subjects of physics, chemistry, mathematics, life science, mechanical engineering, and material science. K-MOOCs will be available in the summer of 2016. Holistic Admissions for Undergraduates Korean universities traditionally put an emphasis on students’ empirical data such as a GPA or the national College Scholastic Ability Test (CSAT) when reviewing applicants for the undergraduate admission. This practice, however, has posed serious challenges, most notably with CSAT’s requirement that the test takes place only once a year. It was simply impossible and unfair to assess students’ capability from the scores of a high-pressure, high-stakes standardized test. In 2009, KAIST changed its undergraduate admission process to consider the whole applicant’s profile, not just looking for students with good grades, but interesting and promising students who would contribute to the campus community in different and diverse ways. KAIST’s admissions officers have taken into account applicants’ interests, passions, special talents, and personality through their personal essays, recommendation letters, extracurricular activities, and intensive interviews. Prior to KAIST’s new policy, no other university in the nation had ever incorporated such a holistic approach to review student applications. Today, most Korean universities have adopted this admission policy. In addition, for the first time in Korea, KAIST offered all freshmen the option to defer the decision on majors, thereby allowing them to explore their interests more freely. Even after declaring majors as sophomores and higher classes, KAIST students can easily change their majors, and undergraduate students can actually create and lead their own research projects. As such, KAIST has continued to offer innovations to provide students with a quality education to foster their potential.
Professor Ki-Jun Jeong Wins the 2015 Dam Yeun Academic Award
The 11th Dam Yeun Academic Award presented by the Korean Society for Biotechnology and Bioengineering (KSBB) to a biologist under 45 years old went to Professor Ki-Jun Jeong of the Chemical and Biomolecular Engineering Department at KAIST. The award ceremony took place on October 13, 2015, at the annual conference of KSBB held at Songdo Convensia in Incheon City. Each year KSBB announces the recipient of the award based on the publications by researchers in the last five years at peer-reviewed international journals or KSBB Journal as well as the record of patent registration and technology transfers. Professor Jeong is recognized for his pioneering research in protein, antibody, cellular engineering, and protein displays and chips.
Professor Sang-Min Bae receives the 2015 IDEA Awards
Professor Sang-min Bae of the Industrial Design Department at KAIST garnered one silver and two bronze awards from the 2015 International Design Excellence Awards (IDEA). Along with iF Design Award and Red Dot Design Awards, the IDEA is regarded as one of the world’s most respected recognition in the field of design. Trash to Bin (T2B), a silver winner in the category of Social Impact Design, is a trash bin made of 1.87 lb (0.85 kg) of discarded papers. Using one-hundred percent recycled paper pulp, each T2B costs under $5 for production. The bin can be fully waterproofed for at least six hours. While satisfying with the industry safety standards, this environmentally-friendly bin can be produced on a large scale using litter energy, but offering the exact same benefit of a general garbage can. Roll-Di, one of the two bronze winners, is a direction indicator that tells which string of screen curtains should be pulled to make the curtain go up or down. As shown in the picture below, Roll-Di can be installed at the bottom of the string, and the “up and down” arrows show which side of the string needs to be pulled to achieve the desired position of the curtain. This simple, yet handy solution to the problem that people frequently make the mistake of pulling the wrong string provides users with greater convenience. The other bronze winner is Printing Solar-cell, an organic cartridge module that prints solar-cells using a domestic, ink-jet printer. With Printing Solar-cell, users can design their own cell patterns and charge their electronics anywhere holding the printed solar-cell on a copy paper. Professor Bae said, “I’ve always tried to design something that is useful for people in need. I consider the IDEA awards an encouragement to keep up with my work toward that goal.” Trash to Bin Roll-Di Printing Solar-cell
A Technology Holding Company Establishes Two Companies Based on Technologies Developed at KAIST
Mirae Holdings is a technology holding company created by four science and technology universities, KAIST, DIGIST (Daegu Gyeongbuk Institute of Science and Technology), GIST (Gwangju Institute of Science and Technology), and UNIST (Ulsan National Institute of Science and Technology) in 2014 to commercialize the universities’ research achievements. The company identifies promising technologies for commercialization, makes business plans, establishes venture capitals, and invests in startup companies. Over the past year, Mirae Holdings has established two venture companies based on the technologies developed at KAIST. In September 2014, it founded Cresem Inc., a company used the anisotropic conductive film (ACF) bonding technology, which was developed by Professor Kyung-Wook Paik of the Material Science and Engineering Department at KAIST. Cresem provides a technology to bond electronic parts ultrasonically. The company is expected to have 860,000 USD worth of sales within the first year of its launching. Last June, Mirae Holdings created another company, Doctor Kitchen, with the technology developed by Professor Gwan-Su Yi of the Bio and Brain Engineering Department at KAIST. Doctor Kitchen supplies precooked food, which helps diabetic patients regulate their diet. The company offers a personalized diet plan to customers so that they can effectively manage their disease and monitor their blood sugar level efficiently. The Chief Executive Officer of Mirae Holdings, Young-Ho Kim, said, “We can assist KAIST researchers who aspire to create a company based on their research outcomes through various stages of startup services such as making business plans, securing venture capitals, and networking with existing businesses.” Young-Ho Kim (left in the picture), the Chief Executive Officer of Mirae Holdings, holds a certificate of company registration with Sang-Min Oh (right in the picture), the Chief Executive Officer of Cresem. Young-Ho Kim (left in the picture), the Chief Executive Officer of Mirae Holdings, holds a certificate of company registration with Jae-Yeun Park (right in the picture), the Chief Executive Officer of Dr. Kitchen.
Polymers with Highly Improved Light-transformation Efficiency
A joint Korean research team, led by Professor Bum-Joon Kim of the Department of Chemical and Biomolecular Engineering at KAIST and Professor Young-Woo Han of the Department of Nanofusion Engineering at Pusan National University, has developed a new type of electrically-conductive polymer for solar batteries with an improved light-transformation efficiency of up to 5%. The team considers it a viable replacement for existing plastic batteries for solar power which is viewed as the energy source of the future. Polymer solar cells have greater structural stability and heat resistance compared to fullerene organic solar cells. However, they have lower light-transformation efficiency—below 4%—compared to 10% of the latter. The low efficiency is due to the failure of blending among the polymers that compose the active layer of the cell. This phenomenon deters the formation and movement of electrons and thus lowers light-transformation efficiency. By manipulating the structure and concentration of conductive polymers, the team was able to effectively increase the polymer blending and increase light-transformation efficiency. The team was able to maximize the efficiency up to 6% which is the highest reported ratio. Professor Kim said, “This research demonstrates that conductive polymer plastics can be used widely for solar cells and batteries for mobile devices.” The research findings were published in the February 18th issue of the Journal of the American Chemical Society (JACS). Picture: Flexible Solar Cell Polymer Developed by the Research Team
Professor Sang Yup Lee Appointed Founding Board Member of Cell Systems
Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering at KAIST has been appointed a member of the founding editorial board of the newly established journal Cell Systems. Cell Systems will be a sister journal of Cell, one of the three most prestigious scientific journals along with Nature and Science, that publishes a wide range of papers on biological engineering. The first issue of Cell Systems will be published this July. Cell Systems plans to publish innovative discoveries, reviews of various research instruments, and research findings on integrated and quantified systems in the field of biology. Professor Lee is a pioneer in metabolic engineering of microorganism with a focus on biopolymers and metabolites production. He is the editor-in-chief of Biotechnology Journal and serves on the editorial board of numerous international journals. He is also a member of the Global Agenda Council of the World Economic Forum and the Presidential Advisory Committee on Science and Technology in Korea. Professor Lee said, “Cell Systems will present research findings that discuss whole biological systems methodically.” He continued, “I hope many research findings of Korean scholars will be published in Cell Systems, which will become a representative journal of systems biology and systems biological engineering.”
Eggshell-like Cell Encapsulation and Degradation Technology Developed
Some bacteria form endospores on cell walls to protect their DNA in case of nutrient deficiency. When an endospore meets a suitable environment for survival, the cell can revert to the original state from which it can reproduce. The technique that can artificially control such phenomenon was developed by an international team of researchers. At first, a cell is wrapped and preserved like an egg. When the cell is needed, the technique allows the endospore to decompose while it is alive. Future applications for this technique include cell-based biosensor, cell therapy, and biocatalyst processes. Professors Insung Choi and Younghoon Lee from the Department of Chemistry at KAIST as well as and Professor Frank Caruso from the University of Melbourne developed this technique which permits a cell to stay alive by coating it with film on a nanometer scale and then to be decomposed while it is alive. The research finding was published in the November 10th issue of Angewandte Chemie International Edition as the lead article. Cell encapsulation allows researchers to capture a cell in a tight capsule while it is alive. It is highly recognized in cell-based applications where the control of cell stability and cell-division is the biggest issue. Traditional cell encapsulation methods utilized organic film or inorganic capsules that are made of organic film moldings. Although these films tightly closed around the cell, because they were not easily decomposable, it was difficult to apply the method. The research team succeeded in encapsulating each cell in a metal-polyphenol film by mixing tannic acid and iron ion solution with yeast cells. Usually extracted from oak barks or grape peels, tannic acid is a natural substance. It forms a metal-polyphenol film within ten seconds when it meets iron ions due to its high affinity with cells. Cells encapsulated with this film presented high survival rates. Since the film forms quickly in a simple manner, it was possible to obtain large amount of encapsulated cells. The research team also found that the metal-polyphenol film was stable in neutral pH, but is easily degradable under a weak acidic condition. Using this property, they were able to control cell division by restoring the cell to its pre-encapsulated state at a desired moment. Protecting the cell from the external environment like an egg shell, the metal-polyphenol film protected the cell against foreign conditions such as lytic enzymes, extended exposure to UV radiation, and silver nanoparticles. The research indicated that the encapsulated cells had a high survival rate even under extreme environments. Professor Lee said that “not only the cells remain alive during the encapsulation stage, but also they can be protected under extreme environment.” He added, “This is an advanced cell encapsulation technology that allows controlling cell-division of those cells through responsive shell degradation on-demand.” Professor Choi commented, “Although the cell encapsulation technology is still in its infancy, as the technology matures the application of cell-manipulation technology will be actualized.” He highlighted that “it will serve as a breakthrough to problems faced by cell-based applications.” Sponsored by the Ministry of Science, ICT and Future Planning and the National Research Foundation of Korea, the research was led by two Master’s candidates, Ji Hun Park and Kyung Hwan Kim, under the joint guidance of research professors from KAIST and the University of Melbourne. Figure 1: Lead article of Angewandte Chemie Background: Shows a live native yeast (in green) encapsulated in a metal-polyphenol film (in red) illustrating the vitality of the yeast Front: A native yeast at each encapsulation stage Pictured on the bottom left is a cell prior to encapsulation. Following the red arrow, the native yeast is in purple to show metal-polyphenol film formed around the cell. The cell after the green arrow is a visualization of the degradation of the film in weak acidic condition. Figure 2: A mimetic diagram of cell encapsulation with a metal-polyphenol film Top: A native yeast before encapsulation Middle: A native yeast encapsulated with Tannic Acid-Fe (III) Nanoshell – cell-division of the encapsulated cell is controlled by pH and the shell is protected against silver nanoparticle, lytic enzyme, and UV-C Bottom: Shell degradation on-demand depending on pH
Ultra-high Resolution 2-dimentional Real-time Image Capture with Super Lens
Ultra-high Resolution 2-dimentional Real-time Image Capture with Super Lens Applications to high-precision semiconductor processing or intracellular structures observation are possible. A joint research team led by Professors Yongkeun Park and Yong-Hoon Cho from the Department of Physics, KAIST, has succeeded in capturing real-time 2D images at a resolution of 100 nm (nanometers), which was impossible with optical lens due to the diffraction limit of light until now. Its future application includes high-precision semiconductor manufacturing process or observation of intracellular structures. This research follows the past research of the super-lens developed by Professor Park last April, using paint spray to observe images that have three times higher resolution than those discovered by conventional optical lens. Since optical lens utilize the refraction of light, the diffraction limit, which prevents achieving focus smaller than the wavelength of light, has always been a barrier for acquiring high-resolution images. In the past, it was impossible to observe objects less than the size of 200 to 300 nm in the visible light spectrum. In order to solve the problem of near-field extinction due to scattering of light, the research team used spray paint consisting of nano-particles massed with dense scattering materials to obtain high-resolution information. Then, by calculating and restoring the first scattering shape of light using the time reversibility of light, the researchers were able to overcome the diffraction limit. The original position of an object to be observed is obtained by deriving the complex trajectory of the light, and reversing the time to locate the particular position of the object. Professor Park said, “This new technology can be used as the core technology in all fields which require optical measurement and control. The existing electron microscopy cannot observe cells without destroying them, but the new technology allows us to visualize at ultra-high resolution without destruction.” The research results were published online in the 9th edition of Physical Review Letters, a prestigious international journal in the field of physics.
Regulatory T Cells Influence Liver Damage of Hepatitis A Patients
Liver damage becomes more severe with the decrease of regulatory T cells “This research will aid the development of hepatitis A targeted drug,” said a KAIST researcher. The KAIST Graduate School of Medical Science and Engineering’s Professor Eui-Cheol Shin and his research team have identified the mechanism, explaining how the regulatory T cells are responsible for the body’s immune system and how they have induced liver damage of hepatitis A patients. The research results were published online in the July 9th edition of ‘Gut,’ the world’s most prominent journal in the field of gastroenterology. Hepatitis A is an acute form of hepatitis caused by hepatitis A virus. The virus spreads through oral contact and enters the body via digestive organs. Regulatory T cells play an important role in maintaining the homeostasis of the body’s immune system by inhibiting the activation of other immune cells. In the case of chronic viral infections, regulatory T cells are known to contribute to the duration of the infection, weakening the immune response to virus infections. However, there has been no information on what roles the regulatory T cells perform in the case of acute viral infections. The research team used the fluorescence flow cytometry technique to determine the number and characteristics of a variety of immune cells, including regulatory T cells, in the blood of hepatitis A patients. Consequently, the researchers confirmed that the decrease in the regulatory T cells immune inhibitory ability was consistent with a significant reduction in the number of regulatory T cells in the blood of hepatitis A patients. Furthermore, it was identified that the more noticeable decrease of regulatory T cells led to the occurrence of a more severe liver injury. The analysis of hepatitis A patient’s blood proved that the cause of the decrease in the number and function of regulatory T cells was the increased expression of cell surface protein ‘Fas,’ which induces cell death. Professor Shin said, “This study is the first case which proposes the mechanism for clinical aspects in not only hepatitis A, but also acute virus infection.” He added on the future prospect of the research that: “In the future, we can prevent tissue damage by inhibiting cell death of regulatory T cells for severe acute viral infections that do not have an effective treatment for the virus itself.” [Picture] The picture shows the process of fluorescence flow cytometry technique to study regulatory T cell in the blood of hepatitis A patients.
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