Publications

Evolutionary selection growth of two-dimensional materials on polycrystalline substrates

Journal: Nature Materials

There is a demand for manufacturing 2D materials with the ultimate quality of single crystals and arbitrary size. Usually, epitaxial growth is considered the method of choice1 in prepar-ing single crystalline thin films but it in turn requires single crystal substrates for deposition. Here we present a different...

Bis-lactam-1,10-phenanthroline (BLPhen), a New Type of Preorganized Mixed N,O-Donor Ligand That Separates Am(III) over Eu(III) with Exceptionally High Efficiency

Journal: Inorganic Chemistry

We report a new family of preorganized bis-lactam-1,10-phenanthroline (BLPhen) complexants that possess both hard and soft donor atoms within a convergent cavity and show unprecedented extraction strength for the trivalent f-block metal ions. BLPhen ligands with saturated and unsaturated δ-lactam rings have notable...

Theoretical prediction of Am(III)/Eu(III) selectivity to aid the design of actinide-lanthanide separation agents

Journal: Dalton Transactions

Selective extraction of minor actinides from lanthanides is a critical step in the reduction of radiotoxicity of spent nuclear fuels. However, the design of suitable ligands for separating chemically similar 4f- and 5f-block trivalent metal ions poses a significant challenge. First-principles calculations should...

Real‐Time Observation of Order‐Disorder Transformation of Organic Cations Induced Phase Transition and Anomalous Photoluminescence in Hybrid Perovskites

Journal: Advanced Materials

A fundamental understanding of the interplay between the microscopic structure and macroscopic optoelectronic properties of organic‐inorganic hybrid perovskite materials is essential to design new materials and improve device performance. However, how exactly the organic cations affect the structural...

Supersonic propagation of lattice energy by phasons in fresnoite

Journal: Nature Communications

Controlling the thermal energy of lattice vibrations separately from electrons is vital to many applications including electronic devices and thermoelectric energy conversion. To remove heat without shorting electrical connections, heat must be carried in the lattice of electrical insulators. Phonons are limited to...

On the structure dependence of CO oxidation over CeO 2 nanocrystals with well-defined surface planes

Journal: Journal of Catalysis

CO oxidation is a model reaction for probing the redox property of ceria-based catalysts. In this study, CO oxidation was investigated over ceria nanocrystals with defined surface planes (nanoshapes) including rods ({110}+{100}), cubes ({100}), and octahedra ({111}). To understand the strong dependence of CO...

Mechanically Robust, Sodium-Ion Conducting Membranes for Nonaqueous Redox Flow Batteries

Journal: ACS Energy Lettters

Sodium-based batteries are promising for grid-storage applications because of significantly lower cost compared to lithium-based systems. The advancement of solid-state and redox-flow sodium-ion batteries requires sodium-ion exchange membranes with high conductivity, electrochemical stability, and mechanical...

Additive manufacturing of anisotropic hybrid NdFeB-SmFeN nylon composite bonded magnets

Journal: ScienceDirect

In this work, we demonstrate a novel method of extrusion-based 3D printing additive manufacturing of bonded magnets comprising 65 vol% anisotropic composite powders of Dy-free magfine Nd-Fe-B and Sm-Fe-N in nylon. The 3D printing was performed using a big area additive manufacturing (BAAM) process. The effects of...

Fabrication of highly dense isotropic Nd-Fe-B nylon bonded magnets via extrusion-based additive manufacturing

Journal: ScienceDirect

Magnetically isotropic bonded magnets with a high loading fraction of 70 vol.% Nd-Fe-B are fabricated via an extrusion-based additive manufacturing, or 3D printing system that enables rapid production of large parts. The density of the printed magnet is ∼ 5.2 g/cm3. The room temperature magnetic...

In situ edge engineering in two-dimensional transition metal dichalcogenides

Journal: Nature Communications

Exerting synthetic control over the edge structure and chemistry of two-dimensional (2D) materials is of critical importance to direct the magnetic, optical, electrical, and catalytic properties for specific applications. Here, we directly image the edge evolution of pores in Mo1−xW x Se2...

Vibrational Spectroscopy of Water with High Spatial Resolution

Journal: Advanced Materials

The ability to examine the vibrational spectra of liquids with nanometer spatial resolution will greatly expand the potential to study liquids and liquid interfaces. In fact, the fundamental properties of water, including complexities in its phase diagram, electrochemistry, and bonding due to nanoscale confinement...

Placing single atoms in graphene with a scanning transmission electron microscope

Journal: Applied Physics Letters

We employ the sub-atomically focused beam of a scanning transmission electron microscope (STEM) to introduce and controllably manipulate individual dopant atoms in a 2D graphene lattice. The electron beam is used to create defects and subsequently sputter adsorbed source materials into the graphene lattice such that...

Fire up the atom forge

Journal: Nature

Electron microscopy is on the brink of a transition. Soon the imaging tool could be used to create structures atom by atom. This sort of control over atomic architecture could transform our basic scientific understanding of materials and pave the way to new classes of devices for quantum computing, spin sensing and...

Knowledge Extraction from Atomically Resolved Images

Journal: ACS Nano

Tremendous strides in experimental capabilities of scanning transmission electron microscopy and scanning tunneling microscopy (STM) over the past 30 years made atomically resolved imaging routine. However, consistent integration and use of atomically resolved data with generative models is unavailable, so...

Machine learning–enabled identification of material phase transitions based on experimental data: Exploring collective dynamics in ferroelectric relaxors

Journal: Science Advances

Exploration of phase transitions and construction of associated phase diagrams are of fundamental importance for condensed matter physics and materials science alike, and remain the focus of extensive research for both theoretical and experimental studies. For the latter, comprehensive studies involving scattering...

Learning surface molecular structures via machine vision

Journal: Nature

Recent advances in high resolution scanning transmission electron and scanning probe microscopies have allowed researchers to perform measurements of materials structural parameters and functional properties in real space with a picometre precision. In many technologically relevant atomic and/or molecular systems,...

Nanoscale mapping of ion diffusion in a lithium-ion battery cathode

Journal: Nature Nanotechnology

The movement of lithium ions into and out of electrodes is central to the operation of lithium-ion batteries. Although this process has been extensively studied at the device level, it remains insufficiently characterized at the nanoscale level of grain clusters, single grains and defects. Here, we probe the...

Measuring oxygen reduction/evolution reactions on the nanoscale

Journal: Nature Chemistry

The efficiency of fuel cells and metal–air batteries is significantly limited by the activation of oxygen reduction and evolution reactions. Despite the well-recognized role of oxygen reaction kinetics on the viability of energy technologies, the governing mechanisms remain elusive and until now have been...

Direct imaging of the spatial and energy distribution of nucleation centres in ferroelectric materials

Journal: Nature Materials

Macroscopic ferroelectric polarization switching, similar to other first-order phase transitions, is controlled by nucleation centres. Despite 50 years of extensive theoretical and experimental effort, the microstructural origins of the Landauer paradox, that is, the experimentally observed low values of coercive...

Directed Atom-by-Atom Assembly of Dopants in Silicon

Journal: ACS Nano

The ability to controllably position single atoms inside materials is key for the ultimate fabrication of devices with functionalities governed by atomic-scale properties. Single bismuth dopant atoms in silicon provide an ideal case study in view of proposals for single-dopant quantum bits. However, bismuth is the...

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