Research Highlights

Research Highlights

Simulations Guide Experiments in Understanding Strain-Dependent Raman Scattering of Black Phosphorus

This work provided a clear understanding of the mechanism for the observed Raman shifts under strain for few-layer black phosphorous (BP).  This understanding settles literature controversy and means that the Raman signatures can be used to develop strain-tuned BP properties.  This is an important step for enabling BP as a key candidate for electronics and photonics applications.

W. Zhu, L. Liang, R. Roberts, J.-F. Lin, and D. Akinwande, "Anisotropic electron phonon interactions in angle-resolved Raman study of strained black phosphorus," ACS Nano 12, 12512−12522 (2018).   DOI:10.1021/acsnano.8b06940

Tuning Biocompatible Polymers with Deuteration

This work is one of the very few studies comparing the effects of partial versus full deuteration on the structures and properties in semicrystalline polymers. The work developed large-scale and precise synthesis of selectively deuterated, poly(ε-caprolactone)s (PCLs) with control over the crystal lattice parameters as a function of the deuteration levels.  Such deuteration effects on biocompatible polymers like  poly(ε-caprolactone)s, potentially enables rational tuning of their structures and properties.

D. Chang, T. Li, L. Li, J. Jakowski, J. Huang, J. Keum, B. Lee, P. V. Bonnesen, M. Zhou, S. Garashchuk, B. G. Sumpter, and K. Hong, "Selectively deuterated poly(ε-caprolactone)s: synthesis and isotope effects on the crystal structures and properties," Macromolecules 51 (22), 9393-9404 (2018).   DOI: 10.1021/acs.macromol.8b01851

3D-Printed Carbon Microelectrodes

This work successfully demonstrated size and geometry customizable carbon microelectrode sensors using  templates produced with the CNMS Nanoscribe. These novel carbon electrodes were then implanted into a rat brain to detect dopamine release in vivo. The work exhibits great promise to mass-fabricate customizable sensors with high reproducibility and could open a platform for the development of novel implantable devices for neurotransmitter detection and neurostimulation in the brain.

C. Yang, Q. Cao, P. Puthongkham, S. T. Lee, M. Ganesana, N. V. Lavrik, and B. J. Venton, "3D-printed carbon electrodes for neurotransmitter detection," Angew.Chem. Int. Ed. 57, 14255–14259 (2018). DOI: 10.1002/anie.201809992

“Channeling” Electrons to a Topological State for Ultrahigh Mobility of Spin Current

This work directly measured the intrinsic surface conductance of topological insulators by using a four-probe scanning tunneling microscope (4-Probe STM) to tune the crossover of bulk-to-surface conductance.  A scattering-free spin transport was revealed at micrometer scale through topological surface states. This required using unique CNMS developments for spin-polarized 4-probe STM to achieve the spin-sensitive multi-probe transport measurements. In this manner, a direct and quantitative measurement of the intrinsic spin-polarized transport associated with topological surface states is possible.

W. Ko, G. D. Nguyen, H. Kim, J. S. Kim, X. G. Zhang, and A.-P. Li, "Accessing the intrinsic spin transport in a topological insulator by controlling the crossover of bulk-to-surface conductance," Phys. Rev. Lett. 121, 176801 (2018).  DOI: 10.1103/PhysRevLett.121.176801

Unlocking Secrets of Controlled Assembly of Bimetallic Nanoparticles on Silica

This research overcomes limitations in poor solubility of heterometallic double complex salt (DCS) precursors by using a clever sequential adsorption of metal cations and anions onto a silica support followed by an efficient reduction step which converts the electrostatically bound pairs into well-defined bimetallic nanoparticles. The synthesis breakthrough enables creation of many previously inaccessible bimetallic systems for a range of catalytic processes.  Successful  acetylene hydrogenation under both competitive and noncompetitive conditions demonstrated their unique performance.

K. Ding, D. A. Cullen, L. Zhang, Z. Cao, A. Roy, I. N. Ivanov, and D. Cao, "A general synthesis approach for supported bimetallic nanoparticles via surface inorganometallic chemistry," Science 362, 560-564 (2018). DOI: 10.1126/science.aau4414

3D Metasurface Enables Quantum Optics

This work shows that nonclassical multiphoton interferences can be achieved at the subwavelength scale in all-dielectric metasurfaces. Simultaneous imaging of multiple projections of quantum states with a single metasurface  enables a robust reconstruction of amplitude, phase, coherence, and entanglement of multiphoton polarization-encoded states.

K. Wang, J. G. Titchener, S. S. Kruk, L. Xu, H.-P. Chung, M. Parry, I. I. Kravchenko, Y.-H. Chen, A. S. Solntsev, Y. S. Kivshar, D. N. Neshev, and A. A. Sukhorukov, "Quantum metasurface for multiphoton interference and state reconstruction," Science 361 (6407), 1104-1108 (2018).   DOI: 10.1126/science.aat8196

“Lighting up” High Response in Thin Film Nanocomposite Sensors

This joint CNMS-CFN research effort built on unique capabilities of two NSRCs and resulted in a new hybrid nanocomposite sensor material with ~20 times higher gravimetric response than pure polymer thin films, and that could be further enhanced by additional 500% under ultraviolet (UV) activation. 

E. S. Muckley, L. Collins, A. V. Ievlev, X. Ye, K. Kisslinger, B. G. Sumpter, N. V. Lavrik, C.-Y. Nam, and I. N. Ivanov, "Light-activated hybrid nanocomposite film for water and oxygen sensing," ACS Appl. Mater. Interfaces 10 (37), 31745-31754 (2018).  DOI: 10.1021/acsami.8b08072

Understanding Motion and Response of Ionic Diblock Copolymer Thin Films for Improved Energy Storage

This work presents a direct observation of electric field induced motion/response of ionic diblockcopolymer thin films with nanoscale resolution using In situ neutron reflectometry measurements and molecular dynamics simulations.

J. W. Dugger, W. Li, M. Chen, T. E. Long, R. J. L. Welbourn, M. W. A. Skoda, J. F. Browning, R. Kumar, and B. S. Lokitz, "Nanoscale resolution of electric-field induced motion in ionic diblock copolymer thin films," ACS Appl. Matter. Interfaces 10 (38), 32678-32687 (2018).   DOI: 10.1021/acsami.8b11220

Isolating Light Element Clusters in Zeolite Materials Via Atom Probe Tomography

Understanding the 3-D distribution and nature of active sites in heterogeneous catalysts is critical to developing useful structure−function relationships but it is very difficult to achieve such 3-D information. By using the CNMS Atom Probe Tomography (APT) the team was able to reveal the 3-D distribution of elements within a zeolite catalysis, SAPO-34, at different processing stages, including template containing, calcined, and methanol-to-hydrocarbons reacted SAPO-34 with Si as the active site. 

J. E. Schmidt, L. Peng, A. L. Paioni, H. L. Ehren, W. Guo, B. Mazumder, D. A. Matthijs de Winter, O. Attila, D. Fu, A. D. Chowdhury, K. Houben, M. Baldus, J. D. Poplawsky, and B. M. Weckhuysen, "Isolating clusters of light elements in molecular sieves with atom probe tomography," J. Am. Chem. Soc. 140, 9154 (2018).   DOI: 10.1021/jacs.8b04494