Functional Nanomaterials 2020: Translating Innovation into Pioneering Technologies: Poster Session II
Sponsored by: TMS Functional Materials Division, TMS: Nanomaterials Committee
Program Organizers: Simona Hunyadi Murph, Savannah River National Laboratory; Huanyu Cheng, Pennsylvania State University; Yong Lin Kong, University of Utah; Min-Kyu Song, Washington State University; Ning Zhang, Baylor University

Tuesday 5:30 PM
February 25, 2020
Room: Sails Pavilion
Location: San Diego Convention Ctr

Session Chair: Simona Hunyadi Murph, SRNL and UGA


N-55: High-performance Piezoelectric Nanogenerator Based on Electrospun Polymer for Powering Smart Wearables: Siddharth Sharma1; Indranil Lahiri1; Partha Roy1; Debrupa Lahiri1; 1IIT Roorkee
    A flexible piezoelectric polymeric mat was prepared by electrospinning for fabricating a piezoelectric nanogenerator. Second phase reinforcements with multi-walled carbon nanotubes (MWCNTs) as carbon nanofillers were used to prepare the nanocomposite mat. It was observed that the addition of a small amount of carbon nanofillers significantly enhances the electrical and piezoelectric properties. The electrospun nanocomposite mat exhibits enhanced electrical and mechanical properties. The electrical and mechanical properties of electrospun nanocomposite mat were compared with those of cast polymeric sheet for use as a nanogenerator. The electrospun nanocomposite mat was observed to exhibit better piezoelectric performance than polymer sheets owing to superior electrical properties. The fabricated nanogenerator can charge a capacitor, a rechargeable battery and can light up commercial LEDs (Light Emitting Diodes), which indicates that this portable and flexible nanogenerator can be used for powering smart wearable or self-powered electronic devices.

N-56: Interfacial Surface Chemistry Effect on Thermal and Electrical Conductivity of Carbon Nanotube-copper Composites: Farhad Daneshvar1; Atif Aziz2; Tan Zhang1; Hung-Jue Sue1; Mark Welland2; 1Texas A&M University; 2University of Cambridge
    Carbon nanotube (CNT) possesses remarkably high thermal and electrical conductivities which makes it an excellent material for light-weight electrically and thermally conductive components. However, translating these nanoscale properties into balk samples has been challenging. One promising solution is fabrication of CNT-Cu composites with high CNT loading. Inherently, these two materials have weak interactions and hence poor bonding. In this work, the effect of CNT surface modification on the morphology, composition, and electrical and thermal properties Cu/CNT composites was studied. For this purpose, the surface of CNTs was functionalized with different surface treatments. These CNTs were used as substrate for growth of copper via a facile electrochemical process. It is observed that by changing the surface functional group on CNT, the morphology and chemical state of the Cu deposits can be controlled. Moreover, thermal and electrical conductivity of CNT-Cu thin films as a function of CNT surface treatment were evaluated.

N-57: Optimized Optical Properties and Mechanical Assessment of AlN/SiO2 Nanomultilayers: Chelsea Appleget1; Andrea Hodge1; 1University of Southern California
     Nanoscale multilayer coatings with alternating layered structures (<100 nm) have been used to synthesize materials with extraordinary mechanical properties. Optical nanomultilayers are composed of layer materials with desirable optical properties, and the layer thicknesses determine light propagation through the material. The interplay of nanolayers increases the potential for multifunctionality, such as maximizing both optical and mechanical performance.In this work, ceramic/ceramic systems were synthesized using DC/RF reactive magnetron sputtering and configurations were designed using predictive calculations to maximize transmittance. Microstructural characterization including TEM and STEM were used to analyze the effect of layer thickness on microstructure and layer interfaces, as well as optical performance from spectrophotometry and ellipsometry measurements. Nanoindentation was performed to analyze hardness and elastic modulus as a function of optical performance. By combining these techniques, the behavior of optical multilayers was explored for the development and synthesis of optical multilayers with high optical and mechanical performance.

N-58: Study of pH Influence in The Synthesis of Copper Nanoparticles Using Ascorbic Acid as Reducing and Stabilizing Agent: Thamiris Martins1; Botelho Junior1; Viviane de Moraes2; Denise Espinosa1; 1USP; 2Mauá Institute of Technology
    The green chemical synthesis of copper nanoparticles (CuNPs) is an alternative which uses chemicals and processes that reduce or eliminate the use and generation of toxic substances, such as ascorbic acid, cyclodextrin, plant extracts, chitosan and gelatine. In this study, precursor solutions of copper sulfate pentahydrate and ascorbic acid were used. The synthesized CuNPs were characterized by UV-vis, EDS, SEM and XRD. The presence of Cu oxide particles and CuNPs was inferred through UV-vis. In the images and compositions of the SEM-EDS were found oxygen and Cu, as well as particles of non-uniform size and morphology. The results showed that at pH 5, agglomerated CuNPs were found. XRD verification was performed on the particulate at pH 5 in which diffraction peaks were attributed to copper structure planes (with dimensions of 1042nm to 3.34nm) and other CuO and Cu2O diffraction peaks that overlapped with Cu phases.

N-59: The Effect of a Ripening Step in the Early Stages of WSe2 Synthesis by Molecular Beam Epitaxy: Peter Litwin1; Costel Constantin2; Stephen McDonnell1; 1University of Virginia; 2James Madison University
    The synthesis of high-quality transition metal dichalcogenides films is of significant interest for potential applications in nanoelectronic and thermoelectric devices. Molecular beam epitaxy is a promising route towards this aim providing fine control over growth conditions. To further the present understanding of processing methods on the quality of transition metal dichalcogenide thin films, we study the effect of using a ripening step in the early stages of WSe2 thin film growth. We use a combination of in-situ low energy electron diffraction and reflective high energy electron diffraction along with ex-situ atomic force microscopy to comment on differences in growth mode and crystallinity. In-situ x-ray photoemission will also be employed to comment on differences in the chemical properties of the grown thin films.

N-60: Thermal Stability of Hafnium Zirconium Oxide on Transition Metal Dichalcogenides: Maria Gabriela Sales1; Shelby Fields1; Samantha Jaszewski1; Sean Smith2; Jon Ihlefeld1; Stephen McDonnell1; 1Department of Materials Science and Engineering, University of Virginia; 2Sandia National Laboratories
    Ferroelectric materials have promising applications in ferroelectric-based transistors for memory and logic, but having a high-quality interface with the semiconducting material presents a challenge. Transition metal dichalcogenides (TMDs) offer a potentially improved interface with ferroelectrics because of their 2D structure with no out-of-plane dangling bonds. For integration of these materials into devices, stability in high temperature processing conditions is required. Therefore, the focus of this work is the thermal stability of the interface of ferroelectric materials with TMDs. For the ferroelectric material, a thin layer of a hafnia and zirconia mixture, HfxZr1-xO2, is grown on TMDs through atomic layer deposition (ALD). Two different types of TMD substrates are compared: geological MoS2 available commercially and WSe2 grown via molecular beam epitaxy (MBE). In addition, the effect of MoS2 functionalization prior to ALD growth is exhibited. X-ray photoelectron spectroscopy (XPS) is the main technique employed to study these ferroelectric/TMD interfaces.