Controlled Synthesis, Processing, and Applications of Structural and Functional Nanomaterials: 1D Nanostructures
Sponsored by: ACerS Basic Science Division, ACerS Electronics Division, ACerS Engineering Ceramics Division
Program Organizers: Haitao Zhang, University of North Carolina at Charlotte; Gurpreet Singh, Kansas State University; Kathy Lu, University of Alabama Birmingham; Edward Gorzkowski, Naval Research Laboratory; Jian Shi, Rensselear Polytechnich University; Michael Naguib, Tulane University; Sanjay Mathur, University of Cologne
Monday 2:00 PM
October 18, 2021
Room: B240/241
Location: Greater Columbus Convention Center
Session Chair: Haitao Zhang, University of North Carolina at Charlotte; Sanjay Mathur, University of Cologne
2:00 PM Invited
Self-Assembled Periodic Nanostructures of SrSnO3 Using Martensitic Phase Transformations: Bharat Jalan1; 1University of Minnesota
We will present rationally designed synthesis of a self-assembled nanostructure using martensitic phase transformations.[1] We demonstrate synthesis of a self-assembled nanostructure on a strain-engineered perovskite SrSnO3 thin film having a "picnic blanket" pattern of two different crystallographic phases, where each phase has sharply different dielectric properties. This has resulted in a nanostructured metamaterial with effectively variable photonic crystal properties. Using chemical doping and strain engineering, these patterns can be designed to have different periodicities. Furthermore, by varying the environment temperature or by varying laser wavelength, the dielectric contrast within a single film can be tuned due to the responsive changes in the relative phase fractions associated with the martensitic phase transformation.[1] A. Prakash, T. Wang, A. Bucsek, T. K. Truttmann, A. Fali, M. Cotrufo, H. Yun, J.-Woo Kim, P. J. Ryan, K. Andre Mkhoyan, A. Alù, Y. Abate, R. D. James, and B. Jalan, Nano Lett. 21 1246 (2021)
2:40 PM
Growth Mechanism Study of Boron Carbide Nanowires: Manira Akter1; Terry Xu1; 1University of North Carolina Charlotte
Bulk boron carbide is a promising high temperature thermoelectric material for power generation. Due to its unique rhombohedral crystal structure, boron carbide exhibits unusual properties such as high temperature stability, high Seebeck coefficient and electrical conductivity, and relatively low thermal conductivity at higher temperatures. However, the figure-of-merit (ZT) value of bulk boron carbide is still low, preventing its wide commercial applications. Recently, boron carbide nanowires with higher-predicted ZT values were synthesized. But their rational synthesis, that requires understanding of the growth mechanisms, is not fully realized yet. To solve the issue, we have started extensive Transmission Electron Microscopy-based cross-sectional examination of boron carbide nanowires. In this presentation, obtained experimental results and proposed growth mechanisms will be discussed. The results help to controlled synthesis of boron carbide nanowires with desired thermoelectric properties.
3:00 PM
Mechanism Study of Controlled Growth of Transition Metal Oxide Nanostructures: Haitao Zhang1; 1University of North Carolina at Charlotte
This talk summarizes our work on the mechanism study of the controlled growth of transitional metal oxide (e.g., WO3, MoO3) nanostructures. Low-temperature non-catalyst selective growth of WO3-x nanowire was realized by applying a growth theory of suppressed spontaneous nucleation. One-dimensional WO3-WS2 core-shell nanostructures were synthesized with an integrated structure-property study on individual heterostructures to reveal the structure-property relation. Fingerprint Raman features were established for a quick identification of few-layer WS2 structures guiding the optical measurements of bandgap transition with the layer thickness. The growth of MoO3 nanostructures was achieved using non-conventional catalysts of alkaline-based compounds. Lateral growth mode of nanobelts and axial growth mode of tower-like structures were discovered. Regular MoO3 nanoribbons with uniform rectangular shapes can be realized by finely tuning the growth conditions. The growth mechanism study reveals important factors affecting the growth sites, growth orientations, and growth morphology for controlled growth of different nanostructures.
3:20 PM Break
3:40 PM
NiO Nanostructure Growth at High Temperature in Water Vapor via In-situ ESEM: Boyi Qu1; Klaus van Benthem1; 1University of California Davis
This study reports on the in-situ growth of NiO nanostructures from nickel nanoparticles at 800 °C under water vapor atmosphere observed by environmental scanning electron microscopy (ESEM). Both high aspect ratio nanorod morphology and particle elongation were observed, with growth rates typically below 1.8 nm/s. Selected area electron diffraction and energy dispersive x-ray spectroscopy has confirmed the nanostructure to be NiO. The growth of nanostructure is enabled by the outward diffusion of nickel and the adsorption of oxidant molecules to the native oxide layer on particle surface. High aspect ratio nanorod forms at grain boundaries of the polycrystalline native oxide layer on particle surface, which serves as fast diffusion paths. Annealing of particles under different oxygen partial pressures before ESEM shows that growth only takes place when particle surface energy is high enough so that the growth can further decrease total surface energies.
4:00 PM
Nanotube Consolidations and Metal-PTFE Nanocomposites for Conformable Thermal and Electrical Interfaces: Christopher Kovacs1; Timothy Haugan2; Robert Ansel3; 1Scintillating Solutions LLC; 2Air Force Research Laboratory; 3Linseis Inc.
Thermal and electrical interfacial resistances directly limit the performance in many applications, and surface asperities play a major role in limiting thermal and electrical transfer. In this research, Metal-Polytetrafluoroethylene (PTFE) nanocomposite and Boron Nitride Nanotube (BNNT) felt consolidations are examined as electrically conductive and electrically insulating conformable thermal interface materials (TIMs) at temperatures up to 300 °C. The thermal interfacial resistivity of these novel TIMs are compared to current state-of-the-art electrically conductive and electrically insulating greases.
4:20 PM
Effect of Doping Carbon Nanotubes with Group III-V Compounds Using Floating Catalyst Method: Anuptha Pujari1; Mark Schulz1; 1Nanoworld Laboratories, University of Cincinnati
Carbon nanotube (CNT) sheets doped with GaN and BN were produced in a horizontal CVD reactor using the floating catalyst method. The synthesis was performed at 1400 °C for 1 h with a fuel injection rate of 30ml/h. Tris(dimethylamido)gallium (III) and Tris(dimethylamino)borane were used as precursors for GaN and BN respectively along with n-hexane and methanol as a carbon source and ferrocene as the catalyst. Hydrogen and argon with a flow rate of 150 sccm and 1400 sccm were used as carrier gases. After synthesis the structure and morphology of the carbon nanotubes in the sheets were studied using SEM secondary imaging. Analysis of the purity and the intrinsic defects of the CNTs were analyzed using Raman spectroscopy. Electrical conductivity measurements were performed using Four Point Probe.