IEN hosted 2 large Fall nanotechnology themed events, drawing big crowds and showcasing even bigger research idea.  On September 6th the 2019 annual User Science and Engineering Review (USER) Day hosted more than 80 attendees and featured a keynote lecture by Julia Greer, Professor of Materials Science, Mechanics, and Medical Engineering at CalTech. Professor Greer’s discussion, “Materials by Design: Three-Dimensional (3D) Nano-Architected Meta-Materials” was a fascinating look at her laboratory team’s research into the fabrication of micro- and nanoarchitected materials and their resultant mechanical, thermal and electrochemical properties.  Her teams use of 3D lithography, nanofabrication, and additive manufacturing (AM) techniques allows for precise nanoarchitectures and paves the way to developing lightweight and resilient new materials for applications ranging from nano-electronic and photonic device development, biomedical devices and manufacturing processes.

Professor Greer’s keynote was followed by presentations from three IEN facility users in varied disciplines. Ting Wang, Ph.D. candidate in Civil and Environmental Engineering, presented “Rapid Determination of the Electroporation Threshold for Bacteria Inactivation Using a Lab-on-a-Chip Platform”. Katie Young, a Materials Science and Engineering Ph.D. candidate, spoke on “The Impact of Defect Density, Grain Size, and Cu Orientation on Thermal Oxidation of Graphene-Coated Cu” and Ph.D. candidate in Chemical & Biomolecular Engineering Yamin Zhang discussed “Zinc Anode Design for Rechargeable Aqueous High-Energy Zn-Air Batteries”.

A reception and poster session followed the lectures, with 21 presentations from facility users. 3 Best Presentation Awards were distributed at the conclusion of the reception. The IEN team congratulates the session winners for their excellent presentations. 

Brummer, Amy and Amar T. Mohabir (Advisors: E. Vogel, MSE & M. Filler, ChBE)
Bottom-Up Patterning and Selective Area Atomic Layer Deposition for Nanowire Electronic Devices
Mini Abstract: Combining a selective etching technique (SCALES) with area-selective atomic layer deposition (AS-ALD), we can fabricate high-performance, fully formed electronic devices using semiconductor nanowires. Since only vapor-phase and solution processing methods will be used, the process can be scaled up to a very large production scale, allowing for massive manufacturing of cheap yet high-performance electronics.
Potential Uses: Large area electronics applications ranging from highly functionalized sensors in building walls, large sensor dust networks to deploy on crops, to smart flexible surfaces.
Presenter Bios: Amy Brummer graduated in 2015 with B.S. in Chemical Engineering from Washington University. She is currently pursuing a Ph.D. in Materials Science and Engineering at Georgia Tech in Dr. Vogel and Dr. Filler’s research groups with a focus on electronic materials applications. Amar Mohabir Graduated in 2015 with a B.S. in Chemical Engineering from the University of Florida. He is currently pursuing a PhD in Chemical & Biomolecular Engineering at Georgia Tech in Dr. Filler’s research group. His focus is on development and optimization of the SCALES technique.

Zifei Sun (Advisor: Gleb Yushin, MSE)
Free-Standing Flexible FeF3-C cathodes for sodium-ion batteries
Mini Abstract: Sodium-ion batteries (SIBs) have recently attracted great attention as a potential alternative to lithium-ion batteries due to ubiquity of sodium reserves. Conversion-type iron trifluoride (FeF3) may become a particularly interesting cathode due to low cost and abundance of Fe and extremely high theoretical capacity of this material (712 mAh g-1). Unfortunately, prior studies showed rather poor capacity and cycling performance of FeF3 due to significant volume changes, morphological changes and various side reactions. Here we demonstrate that by the confinement of FeF3 nanoparticles in flexible carbon nanofibers (CNFs) to mitigate structural changes during cycling and by utilizing sodium difluoro(oxalate) borate (NaDFOB) as a novel electrolyte salt, substantial performance improvements could be attained.
Potential Applications: Time-of-Flight Secondary Ion Mass Spectrometry, Nuclear magnetic resonance spectroscopy, other spectrographic techniques.
Presenter Bio: Zifei Sun graduated from Shandong Normal University in China with a B.S. in chemistry before beginning her Ph.D. work in School of Chemistry and Biochemistry at Georgia Tech. As a member in Prof. Gleb Yushin's lab, Zifei is researching battery materials and design next generation battery system. 

Katherine T. Young (Advisor: E. Vogel, MSE)
The Impact of Defect Density, Grain Size, and Cu Orientation on Thermal Oxidation of  Graphene-Coated Cu
Mini Abstract: Graphene has been shown to be a promising barrier for thermal corrosion due to its low gas and liquid permeability; however, there have been contradictory reports in the literature regarding the mechanisms of oxidation of graphene-coated Cu. This work systematically investigates the effect of chemical vapor deposited graphene grain size, point defect density, and underlying Cu orientation on the thermal oxidation of the underlying Cu in air. For graphene with either small grain size or large point defect density, oxidizers have relatively unhindered access through these defects to corrode the underlying Cu, and the corrosion is relatively independent of Cu orientation. For graphene with low defect density, the rate of Cu oxidation is limited by the quality of the graphene grown on the specific Cu crystal orientation and the orientation with the weakest graphene-metal interaction. Specifically, graphene-coated Cu (110) corrodes much faster than graphene-coated Cu (111), for graphene synthesized using the same conditions. Young, K. T., et al., App. Surf. Sci. 2019.
Potential Applications: 3.2D materials as gas permeation and corrosion barriers.
Presenter Bio: Katie Young graduated from Georgia Tech with a B. S. in Materials Science and Engineering. She is now pursuing her PhD in Materials Science and Engineering at Georgia Tech. Katie is researching 2D materials for permeation applications.

Yamin Zhang (Advisor: Nian Liu ChBE)
Zinc anode design for rechargeable aqueous high-energy Zn-air batteries
Mini Abstract: Metallic zinc as a rechargeable anode material for aqueous batteries has gained tremendous attention with merits of intrinsic safety, low cost, and high theoretical volumetric capacity (5,854 mAh cm-3). Among zinc-based batteries, Zn-air batteries are promising with highest theoretical volumetric energy density (4,931 Wh/L). Rechargeable zinc anode has recently achieved big progress in neutral electrolytes, yet developed slowly in alkaline electrolytes, which are kinetically favorable for air cathodes. Passivation, dissolution, and hydrogen evolution are three main reasons for irreversibility of zinc anodes in alkaline electrolytes. In this work, we report the design of a sub-micron zinc anode sealed with an ion-sieving coating that suppresses hydrogen evolution reaction (HSSN anode). The design is demonstrated with ZnO nanorods coated by TiO2, which overcomes passivation, dissolution, and hydrogen evolution issues simultaneously. It achieves superior reversible deep cycling performance with an electrolyte-to-discharge-capacity ratio as low as 0.14 mL/mAh, discharge capacity as high as 616 mAh/g, and Coulombic efficiency as high as 93.50% at 100% depth of discharge. It can also deeply cycle >520 times (lasting over ~25 days) in a beaker cell with a capacity retention of 621 mAh/g (94.30% Coulombic efficiency). The design principle of this work can potentially be applied to other aqueous and non-aqueous battery electrode materials.
Potential Applications: High-safety Zn-based batteries (eg: Zn-air batteries) for electric vehicles and energy storage.
Presenter Bio: Yamin Zhang is a 4th-year PhD student in Dr. Nian Liu's group in the School of Chemical & Biomolecular Engineering at Georgia Institute of Technology. She received her B.S. in Chemical Engineering and Technology in 2016 at the Tianjin University (TJU), and another B.S. in Finance in 2016 at the Nankai University. She almost won all the top awards in TJU, including National Scholarship, Honor Student Scholarship (TOP10/29350), and Student Science Award (TOP10/29350). She interned in Hefei Guoxuan High-tech Power Energy Co., Ltd in 2017.

If you are interested in presenting your research at the next annual USER Day, please contact Ms. Amy Duke (amy.duke@ien.gatech.edu).

On October 10th, over 100 attendees joined us for the Fall 2019 NanoFANS Forum, this session focused on the topic of flexible and wearable electronics for healthcare applications. Professor Suresh Sitaraman (ME) is the lead of the Flex@Tech research team and kicked off the seminar with Wearable Electronics: State of the Art and Challenges”. Professor  W. Hong Yeo (ME) discussed Wireless, Stretchable Hybrid Electronics for Smart and Connected Physiological Monitoring, with a particular emphasis on pediatric healthcare applications.  Muneeb Zia (Research Engineer; GT) and Bryce Chung (Research Engineer; Emory) teamed up to present their research, 3D Multi-electrode Arrays Fabricated on Flexible Substrate Enabled Single-Unit Recordings of Muscle Activity in a single lecture slot. The day’s series was capped by a presentation from Professor Omer Inan (ECE) Wearable Joint Health Assessment with Acoustic Emission and Bioimpedance Spectroscopy Sensing. After the lectures, guests were invited to tour the IEN fabrications cleanroom and characterization facilities, supported by the NSF and open for use by the academic and industrial research community.

NanoFANS is a twice-yearly event that focuses on the bio-application of new research. If you are interested in learning more about the NanoFANS Forum, please contact Dr. Paul Joseph (paul.joseph@ien.gatech.edu).