Day 2 :
Keynote Forum
Masahiro Hiramoto
Institute for Molecular Science, Japan
Keynote: Band gap science for organic solar cells
Time : 09:30-10:00
Biography:
Masahiro Hiramoto completed his PhD in Chemistry at Osaka University in 1986. He started research on Organic Semiconductors and Organic Solar Cells in 1988 at Graduate School of Engineering, Osaka University. He joined the Institute for Molecular Science in 2008 as Professor. He has published over 130 papers. He is an Inventor of Blended Junction and Tandem Junction for organic solar cells.
Abstract:
Conversion efficiency of organic thin-film solar cell reached 12%. In 1991, I proposed pin junction incorporating codeposited i-interlayer consisting of two kinds of organic semiconductors (so-called bulk heterojunction), which is an indispensable for present organic solar cells. In this paper, band gap science for organic thin-film solar cells including: Sevennines purification of organic semiconductors; p-n-control of organic semiconductors by impurity doping; doping mechanisminvestigated by Kelvin band-mapping; p-n-control of the photovoltaic co-deposited films; ionization sensitization of doping and; ppm-doping effects in the simplest n+p- homo junction organic photovoltaic cells will be presented.
Keynote Forum
Daniel Bellet
University of Grenoble Alpes, France
Keynote: Transparent and conductive nanomaterials
Time : 10:00-10:30
Biography:
Daniel Bellet became an Assistant-Professor at Grenoble University in 1990 and is Professor at Grenoble INP since 1998. He was junior member at IUF (French Institution to promote excellence in research) from 1999 to 2004, and is now the Director of the Academic Research Community Energies at the Région Rhône-Alpes since 2011. His research is focused on Material Physics and more specifically now on Transparent Conductive Nanomaterials. He is a Co-author of more than 120 peer-reviewed publications or proceedings and eight book chapters.
Abstract:
The past few years have seen a considerable amount of research devoted to nanostructured transparent conductive materials, which play a pivotal role in many modern devices as well as in several energy technologies. The latter concern for instance solar cells and light-emitting devices. Currently ITO (tin-doped indium oxide), the most commonly used material for such applications, suffers from two major drawbacks: Indium scarcity and brittleness. This contribution aims at briefly reviewing the main properties of transparent electrodes as well as the challenges which we still face in terms of efficient integration in devices for several energy technologies. A more specific focus will be devoted to two promising TCMs. First the emerging transparent electrodes based on silver nanowire (AgNW) networks, which appear as a promising substitute to ITO with excellent optical and electrical properties fulfilling the requirements for many applications including flexible devices. In addition, the fabrication of these electrodes involves low-temperature processing steps and up-scaling methods, thus making them very appropriate for future use as TE for flexible devices. Their main properties, the influence of post treatments or the network density and nanowire size but as well their stability will be discussed, thanks to both experimental and numerical approaches. We will also show that low cost and atmospheric pressure spatial atomic layer deposition (AP-SALD) technique drastically enhances the stability of AgNW networks thanks to a very conformal coating. The second studied TCM is based on Fluor-doped Tin Oxide (FTO) which exhibits interesting optoelectronic properties. We have shown recently that an even more promising and innovative TCM can be fabricated from S:TiO2-FTO nanocomposites which shows tuneable high haze factors from almost zero to 60% by using a simple and cost effective method. The resulting optoelectronic properties of such TCM appear very well suited for its efficient integration into solar cells.
Keynote Forum
Ming-Yong Han
Institute of Materials Research and Engineering, Singapore
Keynote: Functional nanostructures and energy-driven water splitting
Time : 10:30-11:00
Biography:
Ming-Yong Han completed his PhD in Chemistry at Jilin University. He was at IBM and Indiana University before his current joint appointment as Senior Scientist at Institute of Materials Research and Engineering, Singapore. His research addresses problems at the interfaces of nanoscience, nanotechnology, and optoelectronics/ biotechnology. His papers have been cited for ~15,000 times. His research has been highlighted for more than 300 times. He has more than 30 granted patents or pending applications.
Abstract:
Recent advances in precise control over the shape and size of various nanoparticles have enabled the systematic engineering of their promising properties. To incorporate new functionalities, the different types of nanoparticles are also being coupled to form hybrid nanostructures (e.g. composite, core-shell and Janus) with combined optical, electronic and magnetic properties. In this talk, we will present our recent research on functional nanostructures and energy-driven water splitting.
Keynote Forum
Jiangtao Cheng
Virginia Polytechnic Institute and State University, USA
Keynote: Contact line dynamic of cassie-state wetting on ultrahydrophobic nano-structured surfaces
Time : 11:15-11:45
Biography:
Jiangtao Cheng completed his Bachelor’s degree in Applied Physics at Peking University in 1991; Master’s degree in Computer Science at Purdue University in 2002 and; Doctorate degree in Physics in 2002. In 2007, he accepted an offer from the Teledyne Scientific Company (formerly Rockwell Science Center) as a Research Scientist III for the next four years. He returned to academia in 2011 as an Associate Professor at University of North Texas. In 2015, he joined Department of Mechanical Engineering at Virginia Tech as an Associate Professor. His areas of expertise include: “Sustainable energy and renewable energy; optofluidics and electrofluidics; microfluidics and nanofluidics; thermal-fluid science and heat transfer; thermal management and microelectronics cooling”. Recently, he introduced surface plasmon resonance and terahertz technology in his research in thermal-fluid science.
Abstract:
We report a molecular dynamics (MD) study on the wetting dynamics of Cassie-state water droplets on ultrahydrophobic nano-structured surfaces. The surface materials were selected to be the amorphous polytetrafluoroethylene (PTFE). Our analysis in the framework of molecular kinetic theory (MKT) indicates that nano-droplets of water exhibit a constant unit displacement length of ~6.05±0.48Å regardless of the surface topography. The contact line friction (CLF) originates from the solid-liquid retarding Gw and viscous damping Gvis, and is also influenced by the fraction of solid-liquid contact. Gw is related to the work of adhesion and is independent of the surface structure. The effects of Gw become manifest in the orderly packing of water molecules at the droplet base. As a result of the solid-liquid retarding, a thin depletion layer of ~2.852 Å thick is formed at the droplet base on smooth PTFE surfaces. However, such depletion phenomenon is mitigated on nanostructured surfaces owing to the sagging of the droplet base. The potential of mean force analysis ascribes Gvis to the fluctuations of relationship of ~sin 20 (θ0 is the static contact angle) is derived In liquid density in the vicinity of solidliquid interface. A heuristic essence, the non-sticking feature of ultrahydrophobic structured surfaces (smaller CLF and larger θ0) indeed roots in the reduced solid-liquid contact. On a smooth PTFE surface, the static friction coefficient, which characterizes the static frictional force exerted on the contact line, was found to be on the same order of magnitude as the dynamic viscosity and increase with the droplet size. A non-dimensional number, which signifies the strength of the inherent contact line fluctuation, was put forward to unveil the mechanism of enhanced energy dissipation in nanoscale, whereas such effects would become unapparent in micro scale. Moreover, regarding a liquid droplet on hydrophobic/super hydrophobic surfaces, an approximate solution to the base radius development was derived by an asymptotic expansion approach.
Keynote Forum
Vera I Isaeva
National University of Science and Technology “MISiSâ€, Russia
Keynote: Nanostructured supports design: a prospective way to modern catalysts constructing
Time : 11:45-12:15
Biography:
Vera I Isaeva is a leading Researcher at National University of Science and Technology MISiS, Moscow, Russia. Her activity is focused on “The development of nanostructured materials including MOFs and composites on their basis, from synthesis to application, especially for energy saving processes. She has coauthored over 100 publications in peer-reviewed journals and two book chapters.
Abstract:
Statement of the Problem: Intense research efforts are focused on the development of nanostructured catalysts thanks to their advanced properties regarding activity and selectivity. Numerous works dealing with nanostructured catalysts relate to metal nanoparticles deposited on different supports. Some reports consider nano-porous matrices with well-controlled surfaces. The modulation of textural and compositional properties of nanostructured carriers allows enhancing the performance of heterogeneous catalysts on their basis in a specific process. Besides creation of nano-porosity using appropriate templates in synthesis course like in zeolites and meso-porous silicas other promising way for the design of nanostructured heterogeneous catalysts is the utilization of carriers composed by nanoparticles. In this context, using a novel type of nano-porous matrices - metal-organic frameworks (MOFs) is a promising approach to rational design of supported catalysts. MOFs are hybrid coordination polymers built from small metal clusters and organic linkers and feature 3D-frameworks comprising nanodimensional channels, pores or cavities. The purpose of this study is to explore two principal approaches to design of nanostructured MOFs supports for heterogeneous catalysts. Our work was focused on clarifying the possibility to control the activity and selectivity of the heterogeneous catalyst changing the MOF support dispersion between micro- and nanoscale.
Methodology: MOFs materials in form of nanocrystals and micro-granules were utilized as host matrices for metal nanoparticles deposition. In order to administer the particles size and morphology, we have synthesized MOF samples by MWassisted synthesis at an atmospheric pressure according to the original approach and by convenient solvothermal procedure. The structural characteristics and catalytic performance of M@MOF nano-hybrids based on MOF supports with nano- and micro particles are compared. The catalytic performance of thus obtained M@MOF catalysts was demonstrated in practically important reactions, e.g. hydroformylation and Fisher-Tropsh synthesis.
Findings: This work results demonstrate the strong impact of support crystal size and morphology on the catalytic performance of M@MOFs nano-hybrids.
Conclusion: The activity and selectivity of heterogeneous catalysts can be controlled using MOF materials with different dispersion and morphology as host matrices for MNPs deposition.
Keynote Forum
Ross A Hatton
University of Warwick, UK
Keynote: Copper nanoparticles: Retarding air-oxidation without electrical isolation using organic ligands, and the size dependence of nanoparticle work function
Time : 12:15-12:45
Biography:
Ross A Hatton is an Associate Professor of Physical Chemistry at University of Warwick in UK and is currently holder of a UK Engineering and Physical Science Early Career fellowship (2016-2020). He was awarded his PhD in 2003 at University of Nottingham (UK) and a prestigious five year Royal Academy of Engineering Research Fellowship in 2007. He has published 50 papers in peer reviewed international journals and has a long standing interest in “The utility of nanomaterials in emerging photovoltaic devices, including carbon nanotubes, metal nanoparticles and ultra-thin nano-structured metal window electrodes”.
Abstract:
Copper nanoparticles (Cu NPs) have potential as a cost-effective alternative to gold and silver nanoparticles for many emerging applications, including hybrid materials for plasmonic hot-electron devices and photovoltaics, although their potential has sparsely been explored due to their higher susceptibility to oxidation in air. This talk will present the remarkable findings of a systematic investigation into the correlation between the air-stability of Cu NPs and the structure of the thiolate capping ligand, which turns conventional wisdom about ligand selection to retard air-oxidation on its head. The experimental methodology used is based on monitoring (in real time) the oxidation of isolated nanoparticles tethered to a solid substrate via the evolution of the localized surface plasmon resonance. Additionally, the work function of a metal nanoparticle is a key determinant of the energetics at the interface it forms with a surrounding semiconductor and so knowledge of how this property scales with size is critically important for electronic applications. Classical theory predicts that the work function should increase with decreasing diameter, although experimental evidence to support this is disputed. We have exploited the exceptional stability of ligand capped copper nanoparticles to unambiguously show that the work function of small metal nanoparticles increases with decreasing nanoparticle diameter, using Kelvin probe force microscopy. Together these finding open the door to the development of hybrid electronic materials based on colloidal metal nanoparticles and organic/perovskite/transition metal oxide semiconductors in which the copper nanoparticles are strongly electrically coupled to the surrounding semiconductor.
Keynote Forum
Rainer Timm
Lund University, Sweden
Keynote: Atomic-scale characterization of semiconductor nanowire surfaces during device operation
Time : 12:45-13:15
Biography:
Rainer Timm completed his Doctor of Science at Technische Universität Berlin, Germany, in 2007. After that, he moved to Lund University, Sweden, where he became an Associate Professor of Physics in 2015. He is Vice Head of the Division of Synchrotron Radiation Research, Coordinator of Master’s program in Physics - Materials Science, and member of NanoLund Center for Nanoscience at Lund University. His research focuses on “The characterization of semiconductor nanostructures using scanning probe microscopy and synchrotron-based methods, especially on the correlation of atomic-scale crystal structure, surface electronic properties, and device performance”.
Abstract:
Semiconductor nanowires are promising candidates for next generation electronic and optoelectronic devices and they
are a great playground for materials science, because they give a large flexibility in combining different materials. As an example, III-V semiconductor nanowires can be epitaxial grown on silicon without interfacial defects, allowing to utilize the enhanced charge carrier mobility of III-V materials with low-cost, industrially compatible substrates. Due to the small size and high aspect ratio of nanowires, their properties are to a significant extend determined by surface effects. Atomic-scale surface and interface characterization is therefore crucial for understanding and improving the performance of nanowirebased devices. In this talk, author will present different approaches based on scanning tunneling microscopy and X-ray photoemission spectroscopy for correlating atomic-scale surface structure, chemical composition, and electronic properties of III-V semiconductor-based nanowire hetero¬structures and devices. We map those properties across interfaces between different crystal phases, different doping levels, or different semiconductor materials. Author will focus on atomically resolved scanning tunneling microscopy (STM) results of various GaAs, InAs, InP and InSb nanowire surfaces. By combining STM imaging with scanning tunneling spectroscopy (STS) measurements, we simultaneously study the surface structure and local electronic properties across the interfaces of axial nanowire heterostructures. Our most recent efforts include in-operando and in-situ studies, where we investigate nanowires during device performance or while their surface becomes modified.