Research Highlights

Research Highlights

CNMS Nanofabrication Capabilities Enable QIS Studies

CNMS nanofabrication capabilities were used to create samples that enable cathodoluminescence (CL) observations in a Scanning Transmission Electron Microscope (STEM), illustrating the strong connection between CNMS and the QIS group, and demonstrating key capabilities of interest to the QIS community: Plasmon modes were visualized in e-beam patterned Archimedean nanospirals (J.A. Hachtel et al, Optics Lett., 43, 927 (2018). DOI: 10.1364/OL.43.000927), and strong photon correlations were measured in patterned nanodiamond (M.A. Feldman et al., Phys. Rev. B, 97, 081404(R) (2018). DOI: 10.1103/PhysRevB.97.081404)

Multipurpose Argon Ion Beam for Processing Graphene

Cleaning, milling, and modifying graphene is now possible in a single tool, using Ar ion clusters.

S. Kim, A. V. Ievlev, J. Jakowski, I. V. Vlassiouk, X. Sang, C. Brown, O. Dyck, R. R. Unocic, S. V. Kalinin, A. Belianinov, B. G. Sumpter, S. Jesse, O. S. Ovchinnikova, "Multi-purposed Ar gas cluster ion beam processing for graphene engineering," Carbon 131, 142 (2018). DOI: 10.1016/j.carbon.2018.01.098

Temperature Measurement by a Nanoscale Electron Probe Using Energy Gain and Loss Spectroscopy

The monochromated, aberration-corrected scanning transmission electron microscope (“MAC-STEM”) directly measures the local temperature at the nanoscale, without having to rely on calibration.

J. C. Idrobo, A. R. Lupini, T. Feng, R. R. Unocic, F. S. Walden, D. S. Gardiner, T. C. Lovejoy, N. Dellby, S. T. Pantelides, and O. L. Krivanek, "Temperature measurement by a nanoscale electron probe using energy gain and loss spectroscopy," Phys. Rev. Lett. 120, 095901 (2018).  DOI:https://doi.org/10.1103/PhysRevLett.120.095901

All-Acyrlic Superelastomers

Thermoplastic elastomers (TPEs), such as styrenic based automobile tires, are ubiquitous in our society. But styrenic based TPEs suffer from low upper service temperatures and poorer mechanical properties. Here by using a facile synthesis approach, a new class of all-acrylic superelastomers was developed that show superior mechanical strength and higher upper service temperatures.

W. Lu, A. Goodwin, Y. Wang, P. Yin, W. Wang, J. Zhu, T. Wu, X. Lu, B. Hu, K. Hong, N.-G. Kang, and J. Mays, "All-acrylic superelastomers: facile synthesis and exceptional mechanical behavior," Polymer Chemistry 9, 160 (2018).  DOI: 10.1039/C7PY01518F

Molecular Simulations Provide a Critical Observation for Understanding Polymer Flow

A forty-year-old hypothesis in the classical tube theory for polymer rheology is directly examined by large-scale non-equilibrium molecular dynamics simulations. We show that the characteristic features associated with the chain retraction mechanism are not observed, providing a critical step in improving our understanding of the deformation and flow behavior of polymers.

W.-S. Xu, J.-M.Y. Carrillo, C. N. Lam, B. G. Sumpter, Y. Wang, "Molecular dynamics investigation of a relaxation mechanism of entangled polymers after a large step deformation," ACS Macro Letters 7, 190 (2018). DOI: 10.1021/acsmacrolett.7b00900 

Adding Aluminum to Graphene Enables Nitrogen Conversion into Ammonia

Based on ab initio density functional theory, a material composed of  graphene with the addition of aluminum was designed to enable a versatile conversion of nitrogen into ammonia without relying on transition metals.

Y.-H. Tian, S. Hu, X. Sheng, Y. Duan, J. Jakowski, B. G. Sumpter, and J. Huang, "Non-transition-metal catalytic system for N2 reduction to NH3: a density functional theory study of Al-doped graphene," J. Phys. Chem. Lett. 9, 570 (2018). DOI: 10.1021/acs.jpclett.7b03094

Large-Scale Deposition of Single Crystal Graphene on any Flat Surface

A simple, wafer-scale process is introduced to rapidly grow graphene layers; multiple techniques at CNMS were used to characterize their structure and quality.

Ivan Vlassiouk, Yijing Stehle, Pushpa Raj Pudasaini, Raymond R. Unocic, Philip D. Rack, Arthur P. Baddorf, Ilia N. Ivanov, Nickolay V. Lavrik, Frederick List, Nitant Gupta, Ksenia Bets, Boris I. Yakobson, and Sergei Smirnov, “Evolutionary Selection Growth of Two-Dimensional Materials on Polycrystalline Substrates," Nature Materials 2018. DOI: 10.1038/s41563-018-0019-3

Precisely Sized Channels in Novel Electrodes Enable Electrochemical Water Desalination

Z-contrast Scanning Transmission Electron Microscopy performed at CNMS shows the “tunnel” (or “channel”) structure in stable MnO2 nanowires, which have precisely tuned sizes that give them selectivity to particular ions in brackish water.

B. W. Byles, D. A. Cullen, K. L. More, and E. Pomerantseva, "Tunnel structured manganese oxide nanowires as redox active electrodes for hybrid capacitive deionization," Nano Energy 44, 476-488 (2018). DOI: 10.1016/j.nanoen.2017.12.015

Seeing and Measuring Nanoscale Pores in Industrial Materials

Helium ion microscopy is shown to be a highly promising method to quickly determine porosity on commercial SiO2 samples commonly used for catalysis, outperforming SEM by overcoming charging effects (or requirement of sample pretreatment) and providing higher resolution as well as providing much faster and more detailed information than gas absorption methods.

M. J. Burch, A. V. Ievlev, K. Mahady, H. Hysmith, P. D. Rack, A. Belianinov, and O. S. Ovchinnikova, "Helium ion microscopy for imaging and quantifying porosity at the nanoscale," Anal. Chem. 90, 1370-1375 (2018). DOI: 10.1021/acs.analchem.7b04418

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