News & Events

Speaker: Chwee Teck Lim
Affiliation: Dept. Biomedical Engineering & MBI, NUS
Abstract Details: Graphene and graphene oxide have very unique mechanical, electronic, and optical properties and we have seen their applications as novel electronic materials and in high-performance devices that generate and store energy. Recently, researchers are looking into applying them for use in the biomedical area. Some emerging applications include biosensing, enhanced stem cell differentiation and growth as well as for mass spectrometry. We will review current multidisciplinary research efforts in exploiting these materials for biomedical research and applications and their associated challenges. We will also look at some of the biomedical research being performed here at NUS and the opportunities that these materials can play in providing alternative solutions to some of the unmet needs encountered.
About the Speaker: Prof Lim is a Professor of Bioengineering at NUS, a PI of the Mechanobiology Institute as well as a member of the Graphene Research Centre. His research interests include mechanobiology of human diseases and the development of microfluidic biochips for disease detection and diagnosis. He has also worked on applying graphene for directing stem differentiation and growth. Prof Lim has authored more than 220 peer-reviewed papers (including 30 invited/review articles) and delivered more than 210 plenary/keynote/invited talks. He is currently on the editorial boards of 12 international journals. Prof Lim has won more than 30 research awards and honors including the Credit Suisse Technopreneur of the Year Award, Wall Street Journal Asian Innovation Award (Gold), TechVenture Most Disruptive Innovation Award, Asian Entrepreneurship Award (First Prize) in 2012, President's Technology Award and Faculty Research Award in 2011, IES Prestigious Engineering Achievement Award in 2010 and highly cited author awards and best paper awards in international conferences. His research was cited by the MIT Technology Review magazine as one of the top ten emerging technologies of 2006 that will 'have a significant impact on business, medicine or culture'
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Marco Polini
Affiliation: NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
Abstract Details: In this talk I will review recent progress in the rapidly evolving field of `graphene plasmonics' [1]. In particular, I will focus on the fundamental properties of Dirac plasmons [2,3] in a doped graphene sheet, highlighting the subtle differences with plasmons in ordinary metals and parabolic-band two-dimensional electron liquids. I will then discuss two factors limiting the plasmon lifetime in single-layer graphene, namely electron-impurity scattering [4] and electron-electron collisions beyond the random phase approximation [5]. Finally, I will briefly advertise on-going experimental work in Pisa [6] related to the use of Dirac plasmons for efficient detection of Terahertz radiation in single-layer and bilayer graphene field-effect transistors. References: [1] A.N. Grigorenko, M. Polini, and K.S. Novoselov, Nature Photon. 6, 749 (2012) [2] S.H. Abedinpour et al., Phys. Rev. B 84, 045429 (2011) [3] M. Orlita et al., New J. Phys. 14, 095008 (2012) [4] A. Principi et al., Phys. Rev. B 88, 121405(R) (2013) [5] A. Principi et al., arXiv:1305.4666 (2013). [6] L. Vicarelli et al., Nature Mater. 11, 865 (2012)
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Laurens D.A. Siebbeles
Affiliation: TU Delft
Abstract Details: The seminar will report studies of the behavior of electronic excited states (excitons) and excess charge carriers in conjugated polymers, covalent organic frameworks and semiconductor nanocrstals. These materials have fascinating optical and electronic properties that are of interest for applications in e.g. solar cells, photodiodes, light-emitting diodes, field-effect transistors and nanoscale molecular electronics. We studied the mechanism of charge carrier photogeneration in blend films of conjugated polymers and electron accepting materials by ultrafast optical and terahertz spectroscopy. It will be discussed how material structure affects the spatial extent and motion of excitons and free charge carriers The generation of two or more excited states for the absorption of a single energetic photon is of interest for development of highly efficient (up to 44%) solar cells. Using time-resolved spectroscopy we found that this process of carrier multiplication occurs with high efficiency in films of PbSe quantum dots that are in strong electrical contact due to introduction of small linker molecules. The multiple charges produced by carrier multiplication are found to efficiently escape from recombination in case strong coupling between quantum dots makes them highly mobile. Covalent Organic Frameworks (COFs) are materials with great promise for application in optoelectronics. We carried out microwave conductivity measurements on charges moving in COFs consisting of phthalocyanine units that are strongly coupled by pi-pi stacking. On basis of the experimental results and quantum mechanical calculations, it is inferred that charges move via a band-like mechanism with a mobility that can be as high as ~100 cm2/Vs.
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Michael S. Fuhrer
Abstract Details: The three dimensional strong topological insulator (STI) is a new phase of electronic matter which is distinct from ordinary insulators in that it supports on its surface a conducting two-dimensional surface state whose existence is guaranteed by topology. I will discuss experiments on the STI material Bi2Se3, which has a bulk bandgap of ~300 meV, much greater than room temperature, and a single topological surface state whose electrons obey a massless Dirac equation describing chiral particles with spin-momentum coupling. Parallels will be drawn between the conducting properties of the STI surface state and graphene, whose electrons also obey a two-dimensional Dirac equation, with coupling of momentum to an orbital “pseudospin” degree of freedom. In particular, the minimum conductivity as the Fermi energy approaches the Dirac point in both systems is determined by long-range disorder which breaks the system into electron and hole “puddles”. Scattering by acoustic phonons give a temperature-dependent resistance which is independent of Fermi energy. The chiral STI surface state of Bi2Se3 shows perfect weak anti-localization, difficult to observe in graphene due to imperfect chirality of the carriers.
About the Speaker: School of Physics, Monash University, Clayton, Victoria 3800, Australia and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD 20742-4111, USA
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: B Sriram Shastry
Abstract Details: A novel method for solving the important problem of the tJ model in any dimension is developed, and some applications to  the ARPES (angle resolved photoemission) spectra are provided. The important role of dynamical asymmetry between particles and holes is emphasized
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Chan Yin Thai
Affiliation: Department of Chemistry, NUS
Abstract Details: Semiconductor nanocrystals (NCs), also known as colloidal quantum dots, are well-known for their exhibition of strong quantum confinement effects and have been utilized in applications as diverse as biomedical diagnostics, optical gain media, LED’s and photovoltaics. Several of these applications have been commercialized into products such as fluorescent probes from InvitrogenTM and display technologies from Sony Corporation. While the synthesis of semiconductor NCs was introduced about two decades ago, innovations in the synthetic preparation of these nanoparticles remains to the present day a very active area of research. In this talk, I will describe how recent developments in the synthesis of NCs have produced hierarchically complex structures with dimensions ranging from 1D to 2D (from rods to sheets). I will draw from examples of nanoparticles synthesized in my research group and will elaborate on how some of these structurally complex nanoparticles incorporate multiple functionalities within the same nanostructure or produce physicochemical properties not achievable by conventional quantum dots.
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Irene Yarovsky
Affiliation: Royal Melbourne Institute of Technology, Australia
Abstract Details: The sophisticated tailoring of surfaces to control the interactions between synthetic materials and biomolecular systems is one of the key aims of nanotechnology and nanomedicine today. Recent studies suggest that proteins bind differently to nano-patterned materials and this concept holds a great potential for engineering of novel materials and devices for biomedical applications. At the same time, there is already sufficient evidence that engineered nanomaterials can cross the brain-blood-barrier as well as enter lungs and other organs where they can interfere with the biological molecular machinery [1]. Theoretical computational modelling can help get insights into the molecular mechanisms of biomolecule interactions with nanomaterials which can be exploited to improve molecular recognition needed in biosensors, tissue engineering and drug delivery applications [2,3]. It can also help understand some unintended and undesirable consequences of the presence of nanomaterials in biological environments. However, some serious challenges exist in developing an adequate approach to modelling nano-biosystems with rigor and efficiency [4]. In this talk several examples based on our recent [5-8] and current work with graphitic nanostructures will be presented. These include our development and applications of simulation methodologies for modelling the interactions of proteins and synthetic polymers with graphene, carbon nanotubes and C60 fullerenes in aqueous environment to facilitate a rational design of tailored surfaces for industrial and biomedical applications. I will discuss the molecular insights that computer simulations can provide to complement the experiments as well as the challenges associated with the rigorous and reliable modelling of complex non-homogeneous molecular systems. 1. Biomolecular coronas provide the biological identity of nanosized materials, M.P.Monopoli, C. Aberg, A. Salvati, K.A. Dawson, Nature Nanotechnology 7 (2012) 779. 2. Ordering Surfaces on the Nanoscale: implications for protein adsorption, A. Hung, S. Mwenifumbo, M. Mager, J. Kuna, M. Hembury, F. Stellacci, I. Yarovsky and M. M. Stevens, JACS, 133 (2011) 1438. 3. Amphiphilic amino acids: a key to adsorbing proteins to nanopatterned surfaces?, A. Hung, M. Mager, M. Hembury, F. Stellacci, M. M. Stevens and I. Yarovsky, Chem. Sci., 4 (2013) 928 [front cover] 4. Nanomaterials in biological environment: a review of computer modelling studies, A.J. Makarucha, N. Todorova and I. Yarovsky, Eur. Biophysics Journal, 40 (2011)103 5. Effect of Substrate on the Mechanical Response and Adhesion of PEGylated Surfaces: Insights from All-Atom Simulations, G. Yiapanis, D.J. Henry, S.MacLaughlin, E.J.Evans and I. Yarovsky, Langmuir 28 (2012) 17263-17272 6. Molecular Dynamics Study of Polyester Surfaces and Fullerene Particles in Aqueous Environment, G. Yiapanis, D.J. Henry, E.J. Evans and I. Yarovsky, J. Phys. Chem. C, 112(2008)18141 7. Effect of ageing on interfacial adhesion of polyester and carbon based particles: a Classical Molecular Dynamics Study, G. Yiapanis, D. Henry, E. Evans and I. Yarovsky, J. Phys. Chem. C, 111 (2007) 6465 8. Adhesion between graphite and modified polyester surfaces: a theoretical study, D. Henry, G. Yiapanis, E.Evans and I. Yarovsky, J. Phys. Chem. B, 2005, 109, 17224-17231.
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: David J. Singh
Affiliation: Oak Ridge National Labs, USA
Abstract Details: There is no known thermodynamic or other fundamental physical principle that limits the possible values of the thermoelectric figure of merit, ZT. However, thermoelectric performance requires combinations of materials properties that do not normally occur together, for example, high thermopower combined with high conductivity and high carrier mobility with low lattice thermal conductivity. As a result, high thermoelectric performance is typically found not in materials that follow standard text-book behavior, but in materials with unusual features such as highly non-parabolic or other complex band structures, proximity to lattice instabilities, unusual bonding, etc. In this presentation we discuss different ways of obtaining high ZT along with materials examples and also suggest new directions and possible realizations of them. This work was supported by the Department of Energy through the S3TEC Energy Frontier Research Center.
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Gyula Eres
Affiliation: Oak Ridge National Laboratory
Abstract Details: Carbon nanomaterial synthesis is typically performed at extreme temperatures and pressures that occur in plasmas or flames. During their relaxation the highly non-equilibrium reactive carbon species are trapped in a succession of metastable states corresponding to a broad range of products. The distribution of products is an intrinsic property of the carbon transformation reactions that occur by rearrangements of carbon-carbon bonding configurations during self-assembly from energetically unstable species. Consequently, these distributions are governed by kinetic rather than by thermodynamic constraints. This approach is highly effective in the exploratory phase of research because the desired structures can be isolated and purified for further characterization using chemical separation techniques. However, this approach is impractical for mass production of carbon nanomaterials that is needed for applications. The complexity of these processes is well recognized and the obstacles to synthesis of carbon nanomaterials with desired structure are related to the poor understanding of the barriers and the reaction pathways connecting initial molecular structures to final products. Controlling the assembly of carbon at the molecular level is the most promising avenue for unlocking the secrets of carbon nanomaterial synthesis. The focus of this talk is on chemical vapor deposition processes that occur at milder conditions promising greater control over the product distribution in the formation of carbon nanotubes and graphene. For controlling the reaction conditions we use a molecular beam environment to suppress secondary gas phase reactions and restrict the growth to heterogeneous surface reactions of specific molecular precursors on a single collision level such as acetylene. The carbon deposition kinetics is studied in real-time using time-resolved optical reflectivity methods. Growth kinetics data alone are insufficient to determine the exact reaction mechanisms, but they allow identification of a particular reaction class with a characteristic product distribution that is critical for obtaining carbon nanomaterials with desired properties.
About the Speaker: Dr. Gyula Eres is a senior research staff member in the Materials Science and Technology Division of Oak Ridge National Laboratory, US. He holds a Ph.D. in chemical physics from the University of Illinois at Urbana-Champaign. His current research is focused on understanding the mechanisms and the kinetics of elementary surface processes that control the synthesis and properties of interfaces in epitaxial thin films, superlattices, and nanostructured materials relevant for advanced energy applications. The experimental approach combines energy enhanced and nonequilibrium growth techniques including pulsed laser deposition and supersonic molecular beam epitaxy with in situ time-resolved imaging, diffraction, and spectroscopic techniques such as surface x-ray diffraction, laser based optical diagnostics, mass spectrometry, and reflection high energy electron diffraction.
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.

Speaker: Denis Vasyukov
Affiliation: Graphene Centre, NUS
Abstract Details: Nanoscale SQUIDs with diameters as small as 46 nm were fabricated on the apex of a sharp tip. The nano-SQUIDs have an extremely low flux noise of 50 nF0/Hz^-1/2 and a spin sensitivity of down to 0.38 µB/ Hz^-1/2, which is almost two orders of magnitude better than previous devices. They can also operate over a wide range of magnetic fields, providing a sensitivity of 0.6 µB/Hz^-1/2 at 1 T. The unique geometry of our nano-SQUIDs makes them well suited to scanning probe microscopy, and we used the devices to image vortices in a type -II superconductor, spaced 120 nm apart, and to record magnetic fields due to alternating currents down to 50 nT
Click HERE for directions

—
To view all the upcoming seminars, you can visit: https://graphene.nus.edu.sg/news-events/events/
You may also Like & Subscribe our following channels below to receive instant notifications for new announcements.