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Prof. Wolfgang Peukert's Lecture on carbon nanomaterials (Nov. 11, 2019)

Date Nov. 11 (Mon) 10:45-12:15
Place Room 510, 5F, Building 55S
Title Process technologies for carbon allotropes
Lecturer Prof. Wolfgang Peukert
Institute of Particle Technology, Center of Functional Particle Systems, Friedrich-Alexander University Erlangen-Nurnberg (FAU), Erlangen, Germany
Abstract Fullerenes and recently carbon nanodots (CND), CNTs and 2D-materials including graphene-like structures are highly promising carbon allotropes. Their widespread application requires scalable processes for production, separation and purification. C60 fullerenes are perfectly round, chemically well-defined and of uniform size of around 1 nm. In contrast, the highly promising carbon nanodots show high quantum yield although their exact structure is much less understood. We report on the synthesis of CNDs and chromatographic separation of both materials. For CNTs, we studied a floating catalyst method for their production. Scalable production routes for graphene-like structures via mechanical delamination are studied in detail. Process optimization requires methodologies for efficient characterization of the formed materials. Therefore, analytical ultracentrifugation equipped with novel sensors for absorption and emission spectroscopy is developed and compared to statistical RAMAN mapping with AFM co-localization. We show how to control defect formation and explain why studies of carbon allotropes open new possibilities towards multidimensional particle characterization.
CV Wolfgang Peukert is a chemical engineer who worked 7 years in industry, two of which he spent in Japan with Hosokawa Micron. He is professor at the university Erlangen and director of the interdisciplinary center of Functional Particle Systems. His research interests focus on product design and formulation. He is seeking for unifying principles in the design of particulate products in combination with modelling and optimization strategies. His activities include particle formation via bottom-up and top down techniques in gas and liquid phase. He uses methods from interface science for tailoring particle interactions, colloidal stabilization and ultimately particle properties. Recent activities include comprehensive particle characterization for size, shape and surface properties. He likes to work in interdisciplinary teams, his motto is: Innovation occurs at the interfaces.
https://www.lfg.tf.fau.de/

Dr. Joey D. Ocon's Lecture on Energy Technologies (Sep. 20, 2019)
- The 5th Colloquium on Social Implementation of Advanced Chemical Wisdom -

Date Sep. 20 (Fri) 16:00-17:30
Place Room 202, 2F, Building 52
Title Vertically Integrated Research Approach on Energy Storage Technology Development
Lecturer Prof. Joey D. Ocon
Laboratory of Electrochemical Engineering (LEE), Department of Chemical Engineering, College of Engineering, University of the Philippines Diliman, Quezon City 1101, Philippines
Abstract Since the industrial revolution, societyfs access to affordable and reliable energy has been the identifying cornerstone of the increasing prosperity and economic growth. Electricity, however, has a major Achillesf heel, the challenges of storing it, which makes coping with any variability of demand and supply a major task in any electricity-driven economy. While demand has always varied with the pattern of human energy consumption, nowadays, supply is becoming inherently variable too because of the intermittent nature of wind and solar. Energy storage technologies would allow us to reduce net variability, make better use of variable renewable energy, lessen fossil fuel dependence, and bring enormous benefits. Among energy storage technologies, chemical (e.g. fuel cells, electrolyzers) and electrochemical energy storage (e.g. batteries) play a central role in decarbonizing the worldfs electricity system. Here, I will describe our laboratoryfs multi-disciplinary, vertically integrated research approach in solving challenges in energy storage at various spatiotemporal scales. With energy storage technology development as the central theme, our research activities are attempting to solve key issues in the catalyst screening at the atomic scale, electrode development at the electrochemical cell level, design and development of energy storage devices, and techno-economics of renewable energy-based hybrid systems in off-grid areas. For instance, using ab initio density functional theory (DFT)-based calculations, our team has explored unreported novel dopants in graphene and graphitic carbon nitride for electrocatalytic applications. At the cell level, we are trying to develop novel electrode materials for Mg-ion and Li-S batteries, water electrolysis, fuel cells, photoelectrochemical water splitting, transient biodegradeable batteries, among others. We are continuously developing improved battery packs for solar home systems and hybrid battery energy storage system for household and off-grid systems. At the system level, I will present our recent collaborative work with German researchers on the techno-economic potential of solar PV-battery-diesel hybrid systems for off-grid islands in the Philippines.
OrganizerInstitute for Social Implementation of Advanced Chemical Wisdom, Waseda Research Institute for Science and Engineering, Waseda University

Prof. Michael H. Huang's Lecture on Semiconductor Crystals (Jul. 5, 2019)

Date Jul. 5 (Fri) 13:30-15:00
Place Room 203, 2F, Building 63
Title Strongly Facet-Dependent Properties of Semiconductor Crystals
Lecturer Prof. Michael H. Huang
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
Abstract Our extensive investigations on the various properties of Cu2O, Ag2O, PbS, and Ag3PO4 crystals have shown they possess facet-dependent photocatalytic activity, electrical conductivity, and optical properties.[1] For example, {110}-bound Cu2O rhombic dodecahedra are more photocatalytically active than {111}-bound Cu2O octahedra, but {100}-bound cubes are inactive. Deposition of ZnO, ZnS, CdS, and Ag3PO4 nanostructures on these Cu2O polyhedra can often lead to partial or complete photocatalytic activity suppression despite their favorable bulk band energy alignment. This happens because facet effects should be extended to semiconductor interfaces, and frequently interfacial band bending can make photoexcited charge transfer across the interfaces becomes unfavorable. For electrical conductivity properties, a Cu2O octahedron is highly conductive like a metal, a cube behaves like a semiconductor, while a rhombic dodecahedron is an insulator. The existence of a thin surface layer with dissimilar band structures for different crystal surfaces and thus different degrees of band bending at the crystal surfaces can explain these facet-dependent observations. Recently, we have shown Si and Ge wafers also possess facet-dependent electrical conductivity behaviors.[2,3] We have also synthesized size-tunable Cu2O cubes, octahedra, and rhombic dodecahedra to demonstrate their possession of size- and facet-dependent light absorption and emission properties.[4] This means band diagram of semiconductors must be modified to account for the optical size and facet effects. All these properties are related. Bond length, bond geometry, and frontier orbital electron distributions within in the ultrathin Si and Ge surface layers are different from those of the bulk, showing semiconductor facet effects should have quantum mechanical basis at the orbital level.
[1] Huang, M. H.; Naresh, G.; Chen, H.-S. Facet-Dependent Electrical, Photocatalytic, and Optical Properties of Semiconductor Crystals and Their Implications for Applications. ACS Appl. Mater. Interfaces 2018, 10, 4-15.
[2] Tan, C.-S.; Huang, M. H. Silicon Wafers with Facet-Dependent Electrical Conductivity Properties. Angew. Chem. Int. Ed. 2017, 56, 15339-15343.
[3] Hsieh, P.-L.; Lee, A.-T.; Chen, L.-J.; Huang, M. H. Germanium Wafers Possessing Facet-Dependent Electrical Conductivity Properties. Angew. Chem. Int. Ed. 2018, 57, 16162.
[4] Huang, J.-Y.; Madasu, M.; Huang, M. H. Modified Semiconductor Band Diagrams Constructed from Optical Characterization of Size-Tunable Cu2O Cubes, Octahedra, and Rhombic Dodecahedra. J. Phys. Chem. C 2018, 122, 13027-13033.

Prof. Esko I. Kauppinen's Lecture on Chirality-Selective Synthesis of Single-Wall Carbon Nanotubes (Nov. 15, 2018)

Date 11/15(Thu) 14:30-16:00
Place Room 407, 4F, Building 55S
Title Colorful SWNT thin films with the FC-CVD synthesis via tuning (n,m) distributions
Lecturer Prof. Esko I. Kauppinen
Vice-Dean, Aalto University School of Science & Professor, Department of Applied Physics, Aalto University School of Science
Abstract We have explored floating catalyst chemical vapor deposition (FC-CVD) synthesis of single walled carbon nanotubes (SWNT) for tuning (n,m) distributions. Ferrocene has been used as the catalyst nanoparticle precursor and CO, C2H4, ethanol and toluene as the carbon precursors and CO2, H2O, H2S and tiophene as the respective additives. By introducing various amount of CO2 in FC-CVD with CO as the carbon source and in-situ ferrocene decomposition generated Fe catalyst nanoparticles, we directly synthesized SWNT films with tunable (n,m) i.e. helicity distribution as well as tunable colors [1]. When operating the FC-CVD reactor at the ambient pressure and at 850 oC temperature with 0.25 and 0.37 volume percent of added CO2, the directly deposited SWNT films display green and brown colors, respectively. We ascribed various colors to suitable diameter and narrow (n,m) distributions, which were determined in detail using the electron diffraction. We will present recent results on using ethylene as the carbon source in N2 carrier gas with the addition of H2O vapor to synthesize SWNTs with extremely narrow (n,m) distribution and accordingly directly deposit colorful films. In addition, we discuss the SWNT diameter as well semiconducting fraction tuning with the ethanol and toluene carbon precursors and with ferrocene-thiophene in the H2-H2 carrier gas. Also, we will present recent results on SWNT synthesis when using spark discharge generated single and bimetallic nanoparticles as premade catalysts with C2H4 and H2S in H2-H2 carrier gas.
[1] Y. Liao et al., Direct Synthesis of Colorful Single-Walled Carbon Nanotube Thin Films. J. Am. Chem. Soc. 140, 31, 9797- 9800 (2018).

Prof. Masaaki Hirayama's Lecture on All-Solid-State Batteries (March 23, 2018)

Date 3/23(Fri) 16:00-17:30
Place Room 202, 2F, 54th Building
Title Prospect and present status of all-solid-state batteries
Lecturer Prof. Masaaki Hirayama
Associate Professor, Tokyo Institute of Technology

Prof. Qiang Zhang's Lecture on Lithium-Sulfur Batteries (March 9, 2018)

Date Mar. 9 (Fri) 16:00-17:30
Place Room 202, 2F, 54th Building
Title Advanced Energy Materials for Lithium-Sulfur Batteries
Lecturer Prof. Qiang Zhang
Professor, Department of Chemical Engineering, Tsinghua University, China
Abstract Among various promising candidates with high energy densities, lithium-sulfur (Li-S) batteries with a high theoretical capacity and energy density are highly attractive [1-2]; while the commercial application of Li-S batteries still faces some persistent obstacles, such as the low electrical conductivity of sulfur and lithium sulfide and the dissolution of polysulfides. The introduction of nanocarbon into the field of Li-S batteries sheds a light on the efficient utilization of sulfur by improving the conductivity of the composites and restraining the shuttle of polysulfides. In this presentation, the concept for the rational design of nanocarbon for energy storage is explained. The advances in the use of advanced energy materials in the cathode, separator, and anode is explained [3-14]. New insights on the relationship between the nanostructure and the electrochemical performance are presented.
[1] Peng HJ, Cheng XB, Huang JQ, Zhang Q. Adv Energy Mater 2017, 7, 1700260.
[2] Cheng XB, Zhang R, Zhao CZ, Zhang Q. Chem Rev 2017, 117, 10403.
[3] Peng HJ, Huang JQ, Zhang Q. Chem Soc Rev 2017, 46, 5237.
[4] Zhao MQ, Zhang Q, et al. Nature Commun 2014, 5, 3410.
[5] Peng HJ, Zhang G, Chen X, Zhang ZW, Xu WT, Huang JQ, Zhang Q. Angew Chem Int Ed 2016, 55, 12990.
[6] Peng HJ, Zhang ZW, Huang JQ, Zhang G, Xie J, Xu WT, Shi JL, Chen X, Cheng XB, Zhang Q. Adv. Mater. 2016, 28, 9551.
[7] Cheng XB, Yan C, Chen X, Guan C, Huang JQ, Peng HJ, Zhang R, Yang ST, Zhang Q. Chem 2017, 2, 258.
[8] Zhang XQ, Cheng XB, Chen X, Yan C, Zhang Q. Adv Funct Mater 2017, 27, 1605989.
[9] Peng HJ, Huang JQ, Liu XY, Cheng XB, Xu WT, Zhao CZ, Wei F, Zhang Q. J Am Chem Soc 2017, 139, 8458.
[10] Hou TZ, Xu WT, Chen X, Peng HJ , Huang JQ, Zhang Q. Angew Chem Int Ed 2017, 56, 8178.
[11] Zhang R, Chen XR, Chen X, Cheng XB, Zhang XQ, Yan C, Zhang Q. Angew Chem Int Ed 2017, 56, 7764.
[12] Zhang XQ, Xu R, Chen X, Cheng XB, Zhang R, Chen XR, Zhang Q. Angew Chem Int Ed 2017, 56, 14207.
[13] Kong L, Chen X, Li BQ, Peng HJ, Huang JQ, Xie J, Zhang Q. Adv Mater 2018, 30, 1705219.
[14] Zhang R, Chen X, Shen X, Zhang XQ, Chen XR, Cheng XB, Yan C, Zhao CZ, Zhang Q. Joule 2018, doi:10.1016/j.joule.2018.02.001.

Prof. Masayuki Horio's Lecture on Social Implementation of Technology (February 2, 2018)

Date Feb. 2 (Fri) 16:00-17:30
Place Room 407, 4F, 55th-South Tower
Title Theory of social implementation based on understandings of essences of technologies and trends of society
Lecturer Prof. Masayuki Horio
Professor emeritus, Tokyo University of Agriculture and Technology

Prof. Tatsuoki Kono's Lecture on Hydrogen Energy (January 9, 2018)

Date Jan. 9 (Tue) 15:00-16:30
Place Room 407, 4F, 55th-South Tower
Title Development of hydrogen-based energy supply systems
Lecturer Prof. Tatsuoki Kono
Tohoku University

Prof. Yoshio Ohshita's Lecture on Solar Cells (October 23, 2017)

Date Dec. 5 (Tue) 14:30-16:30
Place Conference Room #1A (West), 1F, 55th-North Tower
Title Current status and future direction of high-efficiency, low-cost crystalline silicon solar cells
Lecturer Prof. Yoshio Ohshita
Toyota Technological Institute

Prof. Wei-Hung Chiang (April 20, 2017)

Date 16:00-17:30 Apr. 20 (Thu)
Place Room 407, 4F, 55th-S Building
Title Atmospheric-pressure controllable synthesis of heteroatom-doped carbon nanomaterials : synthesis, characterizations and applications
Lecturer Prof. Wei-Hung Chiang
Assistant Professor, Department of Chemical Engineering, National Taiwan University of Science and Technology (NTUST), Taiwan
Abstract Recent theoretical and experimental studies have suggested that heteroatom-doped carbon nanomaterials including carbon nanotubes (CNTs) and graphenes as novel materials with exceptional electrochemical property due to the heteroatom doping, making them particularly attractive from both scientific studies and innovation applications including energy storage and conversion, and electrochemical biosensing. Nevertheless, there are few reports investigating the effect of the heteroatom dopant concentrations in carbonaceous materials on their electrochemical properties. The difficulty is because of the lacking of efficient processes to precisely control the heteroatom dopant concentrations on the carbon surface. In this talk, I will introduce an atmospheric-pressure controllable synthesis of heteroatom-doped carbon nanomaterials and further discuss the possible applications.
We show that boron-doped CNTs (BCNTs) with tunable boron atomic concentration can be synthesized by an atmospheric-pressure solution-assisted substitution reaction. We found that boron atomic concentrations in the nanotubes could be tuned by simply controlling the reaction temperature and time on the basis of detailed high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and X-ray photoelectron spectroscopy (XPS) characterizations. It is also noteworthy from a practical point of view that the developed atmospheric-pressure synthesis method is amenable to industrial-scale production since it avoids the need for a vacuum system [1].
Electrochemical characterization indicates a significant enhancement of 25% in the amperometric response for BCNTs with 2.1 at% boron atomic concentration than pristine CNTs, suggesting its potential as efficient catalysts for electrochemical detection of DA [2]. Significantly, we found BCNTs with enhanced thermal stability can be used on counter electrodes of dye-sensitized solar cells, causing a comparable light-to-electricity conversion efficiency of 7.91% to that of the Pt-based cell of 8.03% [3].

References:
1. W.-H. et al., RSC Advance (2015).
2. W.-H. et al., Sensors & Actuators B: Chemical (2017).
3. W.-H. et al., ACS Sustainable Chemistry & Engineering (2017).
Group HP: http://ch2.ntust.edu.tw/files/13-1027-36835.php?Lang=en


Prof. Stephan Hofmann (April 4, 2017)

Date 14:00-15:30 Apr. 4 (Tue)
Place Room 301, 3F, 54th Building
Title Towards integrated manufacturing of 2D materials
Lecturer Prof. Stephan Hofmann
Professor, Department of Engineering, University of Cambridge, UK
Abstract The foremost challenge for 2D materials is, like for so many other nanomaterials, to develop manufacturing and processing techniques that fulfil the industrial demands for quality, quantity, reliability, and low cost. To serve the industrial demand for gelectronic-gradeh 2D materials, we focus on chemical vapour deposition (CVD), and in this talk I will review our recent progress in scalable CVD [1] and device integration approaches of highly crystalline graphene and hexagonal boron nitride (h-BN) films. The systematic use of in-situ metrology, ranging from high-pressure XPS to in-situ STM and environmental electron microscopy, allows us to reveal some of the key mechanisms that dictate crystal phase, structural, defect, interfacial and heterogeneous integration control at industrially relevant conditions [2,3].
We systematically explored the parameter space of atomic layer deposition (ALD) of ultrathin oxides on graphene and can show that by extending the precursor residence time, using either a multiple-pulse sequence or a soaking period, ultrathin continuous AlOx films can be achieved directly on graphene [4]. As we show, these results have model system character for rational two-dimensional (2D)/non-2D material process integration [5]. We also highlight how the interplay between the 2D material and the catalyst is not only important for growth but also decisive for transfer processes and show how intercalation processes allow for instance local Cu oxidation at the interface followed by selective oxide dissolution, which gently releases the 2D material [6]. I will also review our extensive study on charge transfer chemical doping [7], interfacial band engineering for efficient charge injection/extraction, effective wetting, and process compatibility including masking and patterning.

References
[1] Hofmann et al. J. Phys. Chem. Lett. 6, 2714 (2015).
[2] Weatherup et al., Nano Lett. 16, 6196 (2016).
[3] Caneva et al. Nano Lett. 16, 1250 (2016).
[4] Aria et al. ACS Appl. Mater. Interfaces 8, 30564 (2016).
[5] Alexander-Webber et al., 2D Mater. 4, 011008 (2016).
[6] Wang et al. ACS Appl. Mater. Interfaces 8, 33072 (2016).
[7] Sanders et al., Nanoscale 7, 13135 (2015).

Group HP: http://www-g.eng.cam.ac.uk/hofmann/people.php


Prof. Wei-Hung Chiang (December 3, 2016)

Date 13:00-14:30 Dec. 3 (Sat)
Place Room 201, 2F, 54th Building
Title Engineering of Nanostructures using Microplasmas for Catalysis and Biosensing
Lecturer Prof. Wei-Hung Chiang
Assistant Professor, Department of Chemical Engineering, National Taiwan University of Science and Technology (NTUST), Taiwan
Abstract Microplasmas are a special class of electrical discharges formed in geometries where at least one dimension is less than 1 ?m. As a result of their unique scaling, microplasmas operate stably at atmospheric pressure and contain large concentrations of energetic electrons (1-10 eV). These properties are attractive for a range of nanomaterials synthesis and nanostructure engineering [1-3]. Recently the development of carbon nanomaterials such as carbon nanotubes (CNTs) and graphene has been leading us to an exciting direction for both fundamental science and commercial applications because of their exceptional properties. While researchers have achieved significant progress in CNT synthesis, precise control of structure including diameter, wall number, and chirality remains a critical technological challenge due to the unclear role of the catalyst in controlling the CNT structure. Surface enhance Raman scattering (SERS) is a promising technology for various applications including plasmonic devices, photo energy generation and conversion, biomedical detection and chemical sensing. However, this conventional approach to fabricate SERS-active materials is usually time-consuming and laborious. In this presentation, I will discuss these topics in detail, highlighting the advantages of microplasma-based systems for the synthesis of well-defined nanomaterials. These experiments will aid in the rational design and fabrication of nanoparticle alloys for selective growth of CNT structures and may also have significant impact in other catalytic applications including nanowire growth, gas conversion, and fuel cells. Moreover I will present a facile synthesis of silver (Ag) nanoparticles (NPs)/graphene composites using a unique atmospheric-pressure microplasma-assisted electrochemistry. The systematic micro Raman study indicates that the AgNP/graphene composites show superior SERS performance with low detection concentration of 10-10 M of R6G and high enhance factor (EF) about 1~109.

References:
[1] W-H. Chiang and R. M. Sankaran, Appl. Phys. Lett. 91, 121503 (2007).
[2] W-H. Chiang and R. M. Sankaran, Adv. Mater. 20, 4857 (2008).
[3] W-H. Chiang and R. M. Sankaran, Nature Mater. 8, 882 (2009).
Group HP: http://ch2.ntust.edu.tw/files/13-1027-36835.php?Lang=en

Prof. Yanglong Hou (August 1, 2016)

Date 13:30-15:00 Aug. 1(Mon)
Place Large meeting room, 1F, Building 62-W
Title Hybrid Nanostructures for Anode Materials for Lithium-Ion Batteries
Lecturer Prof. Yanglong Hou
Changjiang Chair Professor of Materials Science and Engineering, Peking University, China
Abstract Presently, safe energy storage is one of the most demanding technologies by the developing society. In this regard, lithium ion batteries (LIBs) have got tremendous attention due to their high energy and power densities; have been considered as promising power source for future electric vehicles (EVs). Thus, most of the present research is focused to develop new electrode materials that can bring the realization of these devices for EVs. However, structural disintegration, limited access to redox sites and loss of electrical contact have long been identified as primary reasons for capacity loss and poor cyclic life of these materials. Although nanotechnology plays critical role by developing nanostructures but simple reduction in size introduce new fundamental issues like side reactions and thermally less stable. Thus, a careful design that can inhibit the side reaction by surface protection, make all redox sites accessible by increasing the intrinsic conductivity of the active materials, maintain a continues network for ionic and electronic flow and keeps the structural integrity, resulting improved performance and excellent capacity retention with long cyclic life to meet the requirements set by USABC for electrode materials to use them in EVs. Here, we have developed different hybrid structures of metal oxides, nitrides, sulfides, hydroxides and metal alloys with doped graphene to control above mentioned problems and to achieve the goals set by USABC. All these composites possess extraordinary performances as electrodes of LIBs with long cyclic stability and excellent rate capability. The high performance of the composites based on the synergistic effect of several components in the nanodesign. These strategies to combine the different property enhancing factors in one composite with engineered structures will bring the realization of these devices in road market.

References
1. Mahmood, N.; Zhu, J.; Rehman, S.; Li, Q. and Hou, Y. Nano Energy, 15, 755?765 (2015).
2. Mahmood, N.; Tahirb, M.; Mahmood, A.; Zhu, J.; Cao, C. and Hou, Y., Nano Energy, 11, 267?276 (2015).
3. Mahmood, N. and Hou, Y., Adv. Sci., 1, 1400012 (2014).
4. Li, Q.; Mahmood, N.; Zhu, J.; Hou, Y. and Sun S., Nano Today, 9, 668?683 (2014).
5. Zhang, C.; Hao, R.; Liao H. and Hou, Y., Nano Energy, 2, 88?97 (2013).
6. Zhang, C.; Mahmood, N.; Yin, H.; Liu, F. and Hou, Y., Adv Mater, 25, 4932?4937 (2013).
7. Mahmood, N.; Zhang, C.; Jiang, J.; Liu, F.; Hou, Y., Chem. Eur. J. 19, 5183?5190 (2013).
8. Mahmood, N.; Zhang, C. and Hou, Y., Small , 9, 1321?1328 (2013).
9. Mahmood, N.; Zhang, C.; Liu, F.; Jinghan, Z. and Hou, Y., ACS Nano 11, 10307?10318 (2013).
10. Mahmood, N.; Zhang, C.; Yin, H. and Hou, Y., J. Mater. Chem. A 2, 15?32 (2014).
11. Yin, H.; Zhang, C.; Liu F. and Hou Y., Adv. Funct. Mater. 24, 2930?2937 (2014).
Group HP: http://nbm.coe.pku.edu.cn/

Informal seminar by Mr. Andrew Westover from Vanderbilt University (August 6, 2015)

Date 8/6(Thu) 15:00-17:30
Place Building 54, 2F-203
Multifunctional energy storage systems
Andrew Westover
Ph.D. Candidate, Nanomaterials and Energy Storage Devices Laboratory, Vanderbilt University
Technological developments such as portable electronics, electric vehicles, and renewable energy conversion are driving the need for better and better energy storage systems. Whereas traditional energy storage research focuses on improving the energy density, power density, and reducing the cost multifunctional energy storage systems these routes also show great promise. Two promising and intriguing routes for developing such multifunctional energy storage systems are structural energy storage systems and integrated energy conversion and energy storage systems.
The first of these focuses on multifunctional energy storage materials that can simultaneously store energy and function as a load bearing and structural material. We highlight the use of nanoporous materials, including nanoporous Si and anodized metals that are electrically and mechanically connected to bulk current collectors as an ideal structural energy storage architecture, and present electrochemical measurements while under simultaneous static and dynamic mechanical loads including tensile, shear, compression and vibratory loads for energy storage devices including carbonized porous Si supercapacitors. These devices can operate at commercial energy densities, and power densities, and can operate with minimal degradation under stresses greater than 1 MPa, and under vibratory accelerations greater than 80 g. In addition we show the importance of wet-dry performance on structural energy storage materials, and demonstrate the ability of devices with epoxy-ionic liquid electrolytes to function both mechanically and electrochemically in extreme environmental conditions such as immersion in water.
We also present recent results showing that similar porous Si supercapacitors could be integrated directly into the back of silicon photovoltaics to form a fully integrated energy conversion and storage device, where light caused direct charging in the supercapacitor that could be discharged at a later time. The use of such an integrated system highlights the potential for direct integration of energy storage and conversion systems eliminating energy losses that come from transferring the energy to an external storage system.
Fluidized-bed production of sub-millimiter-long, > 99%-pure carbon nanotubes
Dr. Zhongming Chen
Postdoctoral researcher in Noda Group, Department of Applied Chemistry, Waseda University
Fabrication of large-grain crystalline Si thin films by rapid vapor deposition with in situ melt-crystallization
Yuhei Yamasaki
Master course student in Noda Group, Department of Applied Chemistry, Waseda University
Fabrication of S/GO/CNT electrodes for lithium sulfur battery
Keisuke Hori
Master course student in Noda Group, Department of Applied Chemistry, Waseda University

Informal seminar by Mr. Lorenzo D'Arsie and Ms. Sabina Caneva from University of Cambridge (July 24, 2015)

Date 7/24(Fri) 15:30-17:30
Place Building 65, 1F, Room 108
Stable injection of charge carriers in graphene
Lorenzo D'Arsie
Ph.D. Student, Department of Engineering, University of Cambridge
Although pristine graphene has a high charge carrier mobility, its intrinsic charge carrier density is nearly zero. Doping is therefore necessary for industrial applications of graphene as a transparent, flexible conductor. In previous work we show that it is possible to obtain a significant reduction in resistance, using for example iodine treatment, which is, however, not sufficiently stable for industrial applications. A stable reduction in sheet resistance can be obtained by evaporation of high work function oxides, but the improvement in conductivity in comparison to the iodine treatment is more modest. A combination of stable and strong doping is thus still elusive. In this talk we will focus on a systematic analysis of the doping stability of nitric acid by electrical measurements, X-ray photoemission spectroscopy and Raman spectroscopy, for different treatments and under different environmental conditions. The analysed data is used to develop a procedure to stabilise the acid doping. This improvement in doping stability represents a step towards ITO replacement by graphene.
Rational catalyst engineering for CVD of large, single crystalline domains of monolayer hexagonal boron nitride on iron films
Sabina Caneva
Ph.D. Student, Department of Engineering, University of Cambridge
Large area monolayers of insulating hexagonal boron nitride (h-BN) are highly sought in nanoelectronics due to the range of attractive electronic, chemical and mechanical properties they display, as well as their design compatibility with other 2D layered materials. One of the main challenges to their integration in novel device architectures is the scalable growth of high quality films, which requires control over the domain size and thickness. The use of catalytic growth techniques has become the preferred route towards tailored synthesis.
We demonstrate the growth of large (~0.3 mm side length) h-BN domains via low-pressure chemical vapor deposition (LPCVD) on Fe films. Using complementary selected area electron diffraction (SAED), dark field transmission electron microscopy (DF-TEM) and atomic force microscopy (AFM) we show that the large h-BN domains are monolayers and single crystals. We also demonstrate that an increase in precursor flux leads to a rise in the nucleation density, which can be exploited to achieve full coverage of the Fe catalyst with a uniform and continuous polycrystalline h-BN film. We perform a combination of in-situ X-ray diffraction (XRD) and ex-situ secondary ion mass spectrometry (SIMS) to elucidate the role of the catalyst on the growth of h-BN thin films, and illustrate that interlayer diffusion during annealing plays a central role in controlling the h-BN morphology. Tuning of the diffusion barrier thickness allows us to exclusively nucleate monolayer domains with very low nucleation densities.
Simple and loss-free fabrication of carbon nanotube films for flexible electronics
Hiroyuki Shirae
Ph.D student in Noda Group, Department of Applied Chemistry, Waseda University
Selective precipitation of few/multi-layer graphene on/around h-BN on SiO2 from metal-carbon films
Kohtaro Yamaguchi
Master course student in Noda Group, Department of Applied Chemistry, Waseda University

Dr. Benji Maruyama & Prof. Yoshikazu Homma & Prof. Yuan Chen
Seminar on Carbon Nanotube Growth Technologies (June 26, 2015)

Date 6/26(Fri) 13:15-16:15
Place Building 54, 2F, Room 201
Lecturers Dr. Benji Maruyama, Senior Materials Research Engineer, Materials and Manufacturing Directorate, Air Force Research Laboratory, USA
Prof. Yoshikazu Homma, Department of Physics, Faculty of Science Division I, Tokyo University of Science
Dr. Yuan Chen, Associate Professor of Chemical and Biomolecular Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
13:15- Autonomous experimentation applied to carbon nanotube synthesis
Benji Maruyama1, Daylond Hooper 1,2, Michael Krein3, Jason Poleski3, Rick Barto3, Fred Webber2 and Pavel Nikolaev1,2
1 Air Force Research Laboratory, Materials and Manufacturing Directorate, RXAS, WPAFB, Ohio 45433, USA.
2 UES Inc., Dayton, Ohio 45432, USA.
3 Lockheed Martin Advanced Technology Laboratories, Cherry Hill, NJ 08002, USA

Carbon nanotubes have an exciting array of applications which span mechanical, electrical, thermal and chemical/sensing. However, full exploitation is slowed by a lack of control over synthesis. Despite the two decades since the explosion of work in the area, progress in controlled production of nanotubes is impeded by our lack of understanding of the fundamental mechanisms of nucleation and growth. Our group has endeavored to develop a method that addresses the critical bottlenecks impeding the speed of research by taking advantage of advances in robotics, artificial intelligence, data sciences and in-situ/in-operando characterization.
Our Autonomous Research System, ARES, is capable of designing, executing and evaluating its own CNT growth experiments. Artificial intelligence module based on random tree / genetic algorithm statistical approach analyses experimentally obtained kinetic parameters (rate, time constant, etc.) and proposes new experiments to achieve user-defined objective. These are then executed by ARES automatically and without human intervention, and fed back into the AI module to ensure machine learning.
Recent experiments utilized maximum growth rate as an objective. The normalized difference between the objective and experimentally observed growth rates behaves in a fashion similar to what is typically seen in the control systems, with experimentally observed growth rate oscillating around the target. The convergence can be expressed via cumulative root mean square (RMS) of the rate difference. RMS increases initially (divergence), followed by consistent decrease after ~50 experiments, indicating convergence. That is, after some unsuccessful experimentation, ARES was better able to supply experimental conditions that achieved the objective growth rate. We take this as a clear demonstration of autonomous AI learning: convergence on the objective via closed-loop iterative experimentation without human intervention.
14:15- Single-walled carbon nanotubes growth from nano-carbon seeds
Huafeng Wang, Chisato Yamada, and Yoshikazu Homma
Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
Single-walled carbon nanotubes (SWCNTs) are efficiently synthesized by chemical vapor deposition (CVD) using metal nanoparticle catalysts. However, metal nanoparticles are thermally instable and suffer from ripening during the CVD process, which is one of the causes of limited catalyst lifetime. Another route of SWCNT synthesis is use of nano-carbon seeds such as fullerene fragments and nanotube segments, and promoting SWCNT growth epitaxially from the seeds. Although the yield and growth rate are still low, the new route has the possibility of continuous growth maintaining the chirality of the seed. Therefore, investigation for optimizing the SWCNT growth from nano-carbon seeds is particularly important.
We comprehensively studied the growth of SWCNTs from nano-carbon seeds including fullerene and short nanotubes. Various parameters such as the pretreatment condition, substrates and carbon sources are investigated and their influences on the growth of SWCNT were thoroughly evaluated. By varying these parameters, the pretreatment as well as the growth conditions suitable for hot-wall and cold-wall CVD were established, and the re-growth of nanotubes from nanotube seeds was realized in these two systems. According to our experimental observation, the pretreatment is proven to be an indispensable process used to activate the nano-carbon seed. The growth window is narrow, and the efficiency of re-growth is largely determined by various conditions. On the basis of those experimental results, the process and mechanism of SWCNT re-growth are discussed.
15:15- Tailoring Carbon Nanomaterials for Emerging Applications
Yuan Chen
Chemical and Biomolecular Engineering School of Chemical and Biomedical Engineering Nanyang Technological University N1.2-B1-16, 62 Nanyang Drive, Singapore 637459
Carbon nanotubes, graphene, fullerenes, and mesoporous carbon structures are a new class of carbon materials that hold promises in revolutionizing our life owing to their extraordinary electronic, thermal and mechanical properties. These properties rely on their unique nanoscale structures. My research interests focus on designing and developing chemical processes to (1) synthesize carbon materials with well-defined nanostructures, (2) assemble carbon nanomaterials into functional macroscale structures, and (3) utilize these novel carbon structures for electronics, sustainable energy and environmental applications. Three research topics will be discussed in my talk. First, we demonstrated the feasibility of manipulating the chirality and metallicity of single walled carbon nanotubes (SWCNTs) through catalytic chemical vapor deposition. In particular, sulfur doped cobalt catalysts were developed to selectively grow large-diameter semiconducting (9,8) SWCNTs of 1.17 nm in diameter, which have potential applications in emerging macroelectronics and optoelectronics for future telecommunication. Second, we created novel nanocarbon composites with tailored structures for energy storage and electrocatalysts. We used capillary columns as hydrothermal reactors to assemble graphene and SWCNTs into a unique multiscale hierarchical structured hybrid fiber, which has one of the highest volumetric capacitance among all reported porous carbon materials. The hybrid carbon fibers were employed to construct fiber supercapacitors as energy storage solutions for emerging miniaturized electronics and smart fabrics/textiles. Last, we showed that metallicity, dispersibility, and size governs the antibacterial activity of SWCNTs and graphene, which provide useful insights for developing strategies that can increase their biomedical and environmental application potentials, such as membranes for water treatment, while minimizing their environmental and health risks.

Informal Seminar with Singapore Polytechnique (Dec. 2, 2014)

Date Dec. 2 (Tue.) 14:00-17:00
Place Building 62W, 1F, Main Conference Room
Guests Mr. Lance LIM Wei Seong, Chief Technology Officier, Singapore Polytechnic
Dr. YIN Xi Jiang, Dr. SU Liap Tat, Dr. LI Ping, and Dr. LI Chunxiang,
Advanced Materials Technology Center, Department for Technology, Innovation and Enterprise, Singapore Polytechnic
Dr. LI Ping Introduction for Singapore Polytechnic, Techonology Groups, and Adanced Materials Technology Center.
Talk about research on advanced painting technologies, especially on electromagnetic interference shieldings.
Noda Lab. Noda: Overview of the group activities on practical production and application of carbon- and silicon-based nanomaterials.
Shirae: Loss-free dispersion and printing of carbon nanotubes for flexible electronics.
Kishida: Direct growth of graphene on SiO2 substrates.
Yamasaki: Rapid fabrication of large-grain crystalline Si films for solar-cells.

Prof. Esko I. Kauppinen (Nov. 18, 2014)

Date Nov. 18 (Tue.) 16:00-17:30
Place Building 52th, 3F, Room 301
Title Studies on SWNT bundling for high performance flexible and transparent thin film devices
Lecturer Prof. Esko I. Kauppinen
Professor, Department of Applied Physics, Aalto University School of Science, Finland
Abstract We report recent studies on the synthesis of high quality single-wall carbon nanotubes (SWCNTs) with a ferrocene-based floating catalyst CVD reactor and show that SWCNT networks consisting of highly individualized SWCNTs exhibit substantially improved transparent conductive film (TCF) performance, when compared to previous work with bundled SWCNT TCFs [1]. For these experiments, SWCNT concentration was controllably reduced, leading to reduced bundling probability and formation networks consisting of dominantly individual SWCNTs with mean diameter of 1.1 nm and a narrow helicity distribution near armchair edge, as observed with HR-TEM and electron diffraction techniques. The individual SWCNT networks exhibit excellent performance as transparent conductors with micro-grid patterns [2] showing sheet resistances as low as 67 Ohm/sq. at 97 % transmittance after rapid nitric acid doping.
In addition, we performed a comprehensive statistical analysis of morphology, size and chemical compositions of a large number of catalyst nanoparticles, including both catalytically active and inactive ones, by means of aberration-corrected high-resolution transmission electron microscopy. The average diameter of active nanoparticles (~3.3 nm) is over three times larger than that of SWNTs (~1.1 nm), and more than 50 % of the particles are active i.e. grow the tube. In addition, we used our novel FC-CVD reactor based on spark discharge catalyst generation to experimentally study the effect of bundling on the performance of transparent conducting film (TCF) and thin film transistors (TFT). The synthesis of SWCNTs relies on generation of iron catalyst particles in the diameter range of 4}3 nm with precisely tunable concentration into nitrogen carrier gas with a spark generator, allowing to grow individual and high-quality SWCNTs from CO with well-defined diameter and length distributions. By controlling the gas phase residence time of the as formed SWCNTs prior depositing the network, we controlled the nanotube bundling. The TCFs fabricated of individual SWCNTs have intrinsically higher conductivity to transparency ratio compared to those fabricated of larger bundles. Similarly, network TFTs of individual SWCNTs exhibit higher uniformity in terms of both mobility and ON/OFF ratio compared to larger bundles, with ON/Off ratio up to 108 and mobilities above 100 cm2 V-1s-1, demonstrating the importance of individualization of SWNCTs.
[1] A. Kaskela, A. G. Nasibulin, M. Y. Timmermans, B. Aitchison, A. Papadimitratos, Y. Tian, Z. Zhu, H. Jiang, D. P. Brown, A. Zakhidov, and E. I. Kauppinen, gAerosol-Synthesized SWCNT Networks with Tunable Conductivity and Transparency by a Dry Transfer Technique,h Nano Lett., vol. 10, no. 11, pp. 4349?4355, Nov. 2010.
[2] N. Fukaya, D. Y. Kim, S. Kishimoto, S. Noda, and Y. Ohno, "One-Step Sub-10 um Patterning of Carbon-Nanotube Thin Films for Transparent Conductor Applications", ACS Nano vol. 8, pp. 3285-293, April 2014.

Dr. Ken Ogata (May 7, 2014)

Date May 7 (Wed.) 14:00-16:30
Place Building 55th South, 2F, The 3rd Mtg. Room
Title Revealing lithium-silicide phase transformations in nano-structured silicon-based lithium ion batteries via in situ NMR spectroscopy
Lecturer Dr. Ken Ogata
JSPS Research Fellow at Department of Engineering, University of Cambridge, UK
Abstract Nano-structured silicon anodes are attractive alternatives to graphitic carbons in rechargeable Li-ion batteries, owing to their extremely high capacities. Despite their advantages, numerous issues remain to be addressed, the most basic being to understand the complex kinetics and thermodynamics that control the reactions and structural rearrangements. Elucidating this necessitates real-time in situ metrologies, which are highly challenging, if the whole electrode structure is studied at an atomistic level for multiple cycles under realistic cycling conditions. Here we report that Si nanowires grown on a conducting carbon-fibre support provide a robust model battery system that can be studied by 7Li in situ NMR spectroscopy. The method allows the (de)alloying reactions of the amorphous silicides to be followed in the 2nd cycle and beyond. In combination with density-functional theory calculations, the results provide insight into the a morphous and amorphous-to-crystalline lithium-silicide transformations, particularly those at low voltages, which are highly relevant to practical cycling strategies.

Dr. Thomas W.H. Oates from Germany (Jun. 3, 2013)

Date Jun. 3 (Mon.) 16:00-17:30
Place Building 54th, BF, Room B02
Title Characterizing plasmonic metamaterials and thin films using spectroscopic ellipsometry
Lecturer Dr. Thomas W.H. Oates
Forschungsbereich Material- und Grenzflachenanalytik Leibniz-Institut fur Analytische Wissenschaften - ISAS-Berlin, Germany
(Staff Scientist, Material and Surface Science Division, Leibniz Institute for Analytical Sciences)
Abstract The strong plasmonic resonances observed in nanoscale noble metal structures provide a base for fabricating designer optical components known as metamaterials. Recent advances in modelling and fabrication methods have demonstrated novel materials with unusual properties such as artificial optical magnetism and negative refractive index. However optical characterization of these materials is complicated by their structural dimensions being between the regimes of homogenous bulk materials and diffractive structures such as photonic crystals. This makes the interpretation of reflection and transmission measurements open to debate when assigning traditional optical properties such as refractive index and circular dichroism.
I will present measured polarized reflection (ellipsometric) spectra of split ring resonators and fishnet metamaterials and identify the origin of the observed resonances. I will then discuss the advantages and limitations of describing these materials using bulk homogenous material parameters.

Dr. Placidus Amama from USA (Dec. 4, 2012)

Date Dec. 4 (Tue.) 13:00-14:30
Place Building 54th, 2nd Floor, Room 203
Title Advances in Rational Catalyst Design for Controlled CVD Growth of Carbon Nanotube Carpets
Lecturer Dr. Placidus Amama, Reseach Scientist
University of Dayton Research Institute (UDRI) & Air Force Research Laboratory (AFRL), USA
Abstract There has been growing interest in densely packed, vertically aligned single-walled carbon nanotube (SWCNT) carpets because of their suitability in a growing number of important technological applications. Among the existing methods for the growth of SWCNT carpets, catalytic chemical vapor deposition (CVD) appears to be the most suitable. Using an alumina/Fe catalyst and a suitable carbon feedstock, SWCNT carpets of millimeter-scale heights can be grown via water-assisted CVD. However, for efficient and controlled growth of SWCNT carpets to be achieved, there are several challenges that need to be addressed, such as unexpected or early growth termination of carpets that limits yield, difficulty in performing carpet growth on metallic or non-alumina supporting layers, and the lack of proper understanding of the growth mechanisms of carpets including many important aspects of support-metal interactions.
In my talk, I will discuss the secret role of water during carpet growth and show how the growth termination process can be explained on the basis of Ostwald ripening and subsurface diffusion of the catalyst. Further, I will discuss the relationship between the 3D evolution of Fe catalyst supported on different alumina types and the catalyst behavior (activity and lifetime). Finally, new strategies for improving the activity and lifetime of Fe catalysts during carpet growth will be discussed.

Dr. Toma Susi from Finland (Oct. 25, 2012)

Date Oct. 25 (Thu) 10:00-11:00
Place Building 65th, 2nd Floor, Room 214
Title Floating catalyst synthesis of SWCNT thin films for transparent electrode applications
Lecturer Dr. Toma Susi, Reseach Associate
Toma Susi, Kimmo Mustonen, Antti Kaskela, Joonas Parjanne, Albert G. Nasibulin, Esko I. Kauppinen
NanoMaterials Group, Department of Applied Physics, Aalto University School of Science, Finland
*toma.susiaalto.fi
Abstract The floating catalyst CVD-based deposition process developed at Aalto during the past few years is very advantageous for nanotube thin film fabrication [1]. By eliminating liquid processing prior to deposition altogether it decreases the process duration and process-induced damaging of the nanotubes, and avoids the problem of persistent surfactant residues. Using ferrocene as the catalyst source and carbon monoxide as the carbon precursor, these SWCNT networks can be chemically doped to reach a sheet resistance of as low as 84 Ħ/ at 90% optical transmittance [2].
Alternatively, we have produced catalyst particles using a hot wire generator, and studied the optoelectronic performance of the SWCNT thin films with respect to the properties of both individual nanotubes and their bundles [3]. We found that bundle lengths determined the thin-film performance, as would be expected for highly resistive bundle?bundle junctions. This can be described by a simple resistor network model [4]. Although the bundle diameters play a secondary role by simply affecting the absorption, we found no evidence that contact resistances were affected by the diameters. Our very recent conducting AFM measurements provide direct support for this, contrary to previous reports [5].
Finally, I'll describe our recent efforts directed at replacing carbon monoxide with acetylene as the carbon precursor in an attempt to increase the growth rate and produce longer SWCNT bundles.
[1] A. Kaskela et al., Nano Lett. 10 (2010) 4349-4355, doi:10.1021/nl101680s
[2] A.G. Nasibulin et al., ACS Nano 5 (2011) 3214-3221, doi:10.1021/nn200338r
[3] K. Mustonen et al., just accepted to Beilstein Journal of Nanotechnology
[4] T. Susi et al., Chem. Mater. 23 (2011) 2201-2208, doi:10.1021/cm200111b
[5] P.N. Nirmalraj et al., Nano Lett., 9 (2009) 3890-3895, doi:10.1021/nl9020914


Noda-Hanada Laboratory,
Department of Applied Chemistry,
School of Advanced Science and Engineering,
Waseda University,
3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan