Biography:

Dr. Hao Yu is associate professor at Xi’an Jiaotong-Liverpool University. He received the PhD degree in Condensed Matter Physics from Nanjing University in 2007.  He worked for Suzhou Institute of Nano-tech and Nano-bionics of Chinese Academy of Sciences, from 2007 to 2009. He joined Xi’an Jiaotong-Liverpool University in Feb. 2010. His research interests include spintronics and complex network.

Abstract:

The dynamic magnetization of nanomagnets is significant to spintronic devices in terms of high speed and high density storage technology or logic applications. The dynamics of the macrospin model of a single-domain nanomagnet is investigated in both analytical and numerical methods based on the Landau-Lifshitz-Gilbert equation which is a nonlinear differential equation describing the evolution of magnetization vector. The dynamic hysteresis, namely the magnetic switching under high frequency magnetic field with/without spin transfer torque is analyzed in terms of the evolution of the geometry of loop. The shape of static hysteresis loop is determined by the parameter of damping, meanwhile the shape evolution of  dynamic hysteresis loop is dependent on the magnitude of field and frequency. Frequency-dependent response with resonant peak has been found in the dispersion curve. The phase diagram is obtained to be able to have a clear picture of the dynamic magnetization of nanomagnets driven by periodic field or current.

​

Biography:

Jin Zhang is a tenured Associate Professor with the Department of Chemical and Biochemical Engineering in the University of Western Ontario (Western), Canada. Her research activities are related to the development of new biocompatible nanocomposites with enhanced chemical and physical properties. Dr. Zhang has published over 66 peer-reviewed papers, including Biosensor & Bioelectronics (impact factor, IF: 7.2), J. Eur. Cells & Mater. (IF 5.98), J. of Nanobiotechnology (IF 4.85), J. Chem. Mater. B (IF 4.7), etc. Her group has given over 90 presentations at national and international conferences; she has 3 issued patents, and one patent application. Dr. Zhang has gained many awards, including Early Research Award of Ontario, the Grand Challenges Canada-Canadian Rising Stars in Global Health, Outstanding Mid-Career Achievements in Nanoscience and Nanotechnology in Ontario, etc.

Abstract:

Carbon-based nanomaterials including graphene, graphene oxide, and carbon quantum dots have shown special luminescence properties. This paper focuses on building an aptamer sensor by using carbon quantum dots (C-dots) and graphene oxide nanosheet. C-dots were synthesized by microwave-assisted process. The average particle size of C-dots is estimated at 23±5 nm. The fluorescence emission of C-dots shifts from 450 to 600 nm when excitation increases from 350-450nm. The target-DNA is conjugated onto C-dots by different strategies. Meanwhile, the capture-DNA is modified on the surface of graphene oxide. The target-DNA conjugated with Carbon Dots can be hybridized with the capture-DNA conjugated with graphene oxide by hydrogen bonds between adenine and thymine, which can cause the fluorescence quench of C-dots. The fluorescence intensity of C-dots modified with target-DNA as a function of the concentration of capture-DNA modified graphene oxide nanosheet is investigated. The results indicate that the this solution-based sensor can quickly measure the target-DNA in the range of 1µg/mL to 100 µg/mL.

Biography:

Jonathan P. Hill is Chief Scientist at the Supermolecules Group, National Institute for Materials Science, Japan. His main research interests are the synthesis and assembly of organic molecular and nanostructures for potential applications in molecular electronics, sensing and related fields. He is coauthor of more than 350 published papers and 20 patents on these subjects. He is also author of more than 300 invited and contributed presentations at international conferences and university seminars.

Abstract:

Supramolecular arrangement of porphyrins and other molecules has great potential in the fields of molecular information storage and sensing due to their ease of deposition and good chemical and thermal stabilities. In particular, porphyrins of relatively large molecular weights can be applied in thermal deposition while tetrapyrrole molecules have had an extensive synthetic chemistry developed, which enables synthesis of complex derivatives. In this work, we present complementary examples of porphyrin nanoarchitectonics. Starting from simple symmetrical phenol derivatives, we describe the effects of steric hindrance about the respective hydroxyl groups and also the effects of conformational variation on the self-assembly structures. We also investigated fabrication of binary molecular monolayers using two different porphyrin molecules tetrakis(3,5-di-t-butyl-4-hydroxyphenyl) porphyrin and tetrakis(4-pyridyl) porphyrin by deposition in ultrahigh vacuum. This leads to two unusual heteromolecular monolayer structures were observed with one exhibiting good separation of molecules within the monolayer. Meanwhile, a synthetic nanoarchitectonic approach was used to prepare self-assembled molecular nanowires at a mica substrate. The nanowires could be observed growing using atomic force microscopy (AFM) and the network structures of the nanowires can be influenced by manipulation using the AFM probe tip. Formation of molecular monolayers with chromophores positioned remote from the substrate surface will also be discussed. Additionally, the synthesis and self-assembly at surfaces of novel heteroacenes will be described and the potential importance of these materials in several applications will be discussed.

Biography:

Prof. Seung Hwan Ko is a professor in Applied Nano & Thermal Science Lab, Mechanical Engineering dept., Seoul National University, Korea. Before joining Seoul National University, he was a faculty at graduate school of EEWS (Energy, Environment, Water and Sustainability), KI nano century, and Department of Mechanical Engineering at KAIST (Korea Advanced Institute of Science and Technology), Korea. He received his Ph.D. degree in mechanical engineering from UC Berkeley in 2006. He worked as a researcher at Lawrence Berkeley National Lab until 2009. His research interest is laser assisted nano/micro fabrication process development, laser-nanomaterial interaction, low temperature process development for flexible, stretchable and wearable electronics, and crack assisted nanomanufacturing.

Abstract:

It is well expected that the future electronics will be in the form of “wearable electronics”. Google’s Smart Glass and Apple’s iWatch are the first generations of wearable electronics. However, they are still mainly composed of rigid electronics even though human body is soft and elastic. To realize more meaningful and practical wearable electronics, electronic components should be stretchable or at least flexible. We developed various hierarchical multiscale hybrid nanocomposite for highly stretchable, highly flexible or highly transparent conductors ultimately applied for wearable electronics applications. The hybrid nanocomposite combine the enhanced mechanical compliance, electrical conductivity and optical transparency of small CNTs (d~1.2 nm) and the enhanced electrical conductivity of relatively bigger AgNW (d~150 nm) backbone to provide efficient multiscale electron transport path with AgNW current backbone collector and local CNT percolation network. Additionally, this approach combine “materials that stretch” and “structure that stretch” strategies to demonstrate highly stretchable conductor.

As a feasibility test of our hierarchical multiscale hybrid nanocomposite stretchable and transparent conductor research, we demonstrated a highly stretchable LED circuit and a touch panel. This is just a very tiny fraction of application area of our works. We expect our approach can be applied to huge range of wearable electronics elements such as high performance displays, solar cells, sensors, touch screens in flexible and stretchable forms and ultimately to all future electronics. Therefore, this research results have a great ripple effect on various future electronics development and will be sustainably studied. Considering the huge impact, originality and advantages of our research results, this paper will provide basic research results and becomes a classical reference for future wearable electronics field.

Biography:

Dr Angéline Poulon is an associate professor at the University of Bordeaux and ICMCB. She has a long experience in the correlation between process parameters, microstructure and properties of structural and functional materials. Her current interests range from the search for innovative multifunctional coatings to the development of green processes to elaborate intermetallic compounds, for applications in energy, aerospace and aeronautical industries. She is a specialist in fine characterization with an extended recognized experience in electronic microscopy and physico-chemical techniques. She has co-authored 31 peer-reviewed articles, 37 oral presentations, 12 invited conferences and 4 patents.

Abstract:

Thermoelectric (TE) materials have received a lot of interest for decades for power generation applications in waste heat recovery or energy harvesting by conversion of waste thermal energy into useful electricity. The performance of TE devices depends on the dimensionless figure of merit ZT = (α²σ/κ)T, where α is the Seebeck coefficient, σ and κ the electrical and thermal conductivities, respectively, and T is the absolute temperature. Many TE materials have been developed such as Bi₂Te₃, PbTe, Mg₂Si, Zn₄Sb₃, filled skutterudites and SiGe. Among them, skutterudite compounds MX₃ (M = Co, Rh or Ir; X = P, As or Sb) crystalized in the bcc structure Im3 are promising TE materials. The binary skutterudite CoSb₃ exhibits a large Seebeck coefficient and a high electrical conductivity. However, its high thermal conductivity makes it difficult to be an efficient TE material. Nanostructuration is an effective approach to lower thermal conductivity. While physical methods allow high purity microparticles synthesis, solution routes are the most effective methods to produce CoSb₃ nanoparticles with a few nanometer size and have advantages of low cost, low processing temperature (< 300°C) and high reproducibility, allowing possible large-scale production, even if they suffer from long reaction time, multiple reaction steps and impurity presence. Supercritical fluid routes have emerged from the two last decades as novel efficient approaches to synthetize metal nanoparticles with the control of their physicochemical properties as size, morphology, crystallographic structure and composition. We report the first fast and continuous supercritical fluids synthesis of cobalt antimony intermetallic nanoparticles (4-5 nm) with a high reliability.

Biography:

Haruki Yamane received the B.S. degree in Physics from Ehime University in 1987, and his Ph.D. in School of Engineering from the University of Tokyo in 1996. From 1989 to 1999 he was with Oki Electric Industry Co., Ltd., and in 1999 he joined Akita Industrial Technology Center. His research interests include magnetic properties of nanostructures and photonic devices using magneto-optical activities. Nano-photonics on magnetic nanostructured materials has recently become an active area of research. He is a member of the Japan Society of Applied Physics, the Magnetic Society of Japan, and the Japan Institute of Metals and Materials. Currently he is working as a Research Officer at Akita Industrial Technology Center, Japan.

Abstract:

The interaction between magneto-optical (MO) activities and plasmons has been intensively investigated from fundamental and applied viewpoints. Improvement of the MO effect is desirable in practical applications such as information storage systems, telecommunications, and chemical and biological sensors. In this presentation, the MO properties of perpendicular magnetic nanostructures consisting of a hexagonal close-packed Co₈₀Pt₂₀ nano-layer and noble-metal (Ag or Au) nanoparticles were investigated under polar Kerr measurement conditions. The samples exhibited an unusual MO hysteresis loop in which the Kerr rotation angle increased at a low magnetic field; this effect was observed at a different wavelength region for the CoPt–Ag and CoPt–Au samples. The nanostructures consisted of two magnetic regions of CoPt layers formed on the nanoparticles and on the underlayer. The increase in the Kerr angle was induced by the antiparallel magnetic alignment of these CoPt layers. The opposite MO polarity on the CoPt nanostructures was suggested also in a micro-MO observation using scanning near-field polarized optical microscopy. The Ag and Au nanoparticles induced the MO phase reversal at a different wavelength region for each plasmon excitation. The MO behaviors on the CoPt nanostructure are attributed to the influence of localized surface plasmons excited on the noble-metal nanoparticles. The magneto-plasmonic activities on the nanostructures were also changed by the underlayer material and the external environmental conditions. We have demonstrated the magneto-plasmon sensor consisting of the CoPt−Ag by detecting the change in external environment (optical index), and a new detection parameter using MO activities has been proposed. The perpendicular magnetic nanostructures are expected to provide a new type of probe for chemical and biological sensing applications.

Biography:

Hyunhyub Ko is currently an Associate Professor in Energy and Chemical Engineering at Ulsan National Institute of Science and Technology. He has received his PhD in Materials Science and Engineering from Georgia Institute of Technology in 2008, MS in Materials Science and Engineering from Iowa State University in 2004, MS in Chemical Engineering from Yonsei University in 2001 and BS in Chemical Engineering from Chung-Ang University in 1999. From 2008 to 2010, he worked at University of California, Berkeley as a Postdoctoral Fellow in the Department of Electrical Engineering and Computer Sciences. His research interests are in the area of functional nano-materials for flexible electronics, sensors and energy devices.

Abstract:

Flexible physical sensors with high sensitivities have gained great attentions in the fields of wearable devices, robotic skins and biomedical diagnostics. In human fingertip skins, fingerprint patterns and interlocked epidermal-dermal micro-ridges have critical roles in amplifying and transferring tactile signals to various mechanoreceptors, enabling spatio-temporal perception of various static and dynamic tactile signals. Here, mimicking the structures and functions of fingertip skin, we introduce highly-sensitive, multifunctional and stretchable electronic skins. Inspired by the interlocked microstructures found in epidermal-dermal ridges in human skin, piezoresistive interlocked micro-domes are employed for the demonstration of stress-direction-sensitive, stretchable electronic skins. We show that interlocked micro-dome arrays possess highly direction-sensitive detection capability of various mechanical stimuli including normal, shear, stretching, bending and twisting forces. We also demonstrate that ferroelectric skins with fingerprint-like patterns and interlocked microstructures can detect and discriminate multiple spatio-temporal tactile stimuli including static and dynamic pressure, vibration and temperature with high sensitivities. For applications, we demonstrate that stretchable electronic skins attached on the human skin can be used as wearable healthcare monitoring devices, which are able to distinguish various mechanical stimuli applied in different directions, selectively monitor different intensities and directions of air flows and vibrations, and sensitively monitor human breathing flows and voice vibrations. In addition, dynamic touch sensing ability is employed for the precise detection of acoustic sounds, and discrimination of various surface textures. Finally, for multifunctional wearable and skin-attachable devices, we show smart adhesive pads with temperature-responsive adhesion properties and force-dependent color changing touch screens based on mechanochromic surface coatings.