A5067699683- Advanced Electron Microscopy Techniques and Applications
- Quantum Dots Synthesis And Properties
- Multiferroics and related materials
- Advanced Memory and Neural Computing
- Electron and X-Ray Spectroscopy Techniques
- Copper-based nanomaterials and applications
- Ferroelectric and Piezoelectric Materials
- Iron oxide chemistry and applications
- Electrocatalysts for Energy Conversion
- Semiconductor materials and devices
- nanoparticles nucleation surface interactions
- Ferroelectric and Negative Capacitance Devices
- Chalcogenide Semiconductor Thin Films
- Advancements in Battery Materials
- Electronic and Structural Properties of Oxides
- Gold and Silver Nanoparticles Synthesis and Applications
- Electrochemical Analysis and Applications
- Advanced Battery Materials and Technologies
- Catalytic Processes in Materials Science
- Force Microscopy Techniques and Applications
- Radio Astronomy Observations and Technology
- Transition Metal Oxide Nanomaterials
- Advanced Battery Technologies Research
- Magnetic and transport properties of perovskites and related materials
- Nanowire Synthesis and Applications
Lawrence Berkeley National Laboratory
2016-2025
University of California, Berkeley
2016-2025
Massachusetts Institute of Technology
2018-2025
University of California System
2014-2025
National Yang Ming Chiao Tung University
2024
Shaanxi University of Science and Technology
2023-2024
Nanfang Hospital
2024
National Sun Yat-sen University
2016-2022
State Key Laboratory of Mechanical System and Vibration
2022
Shanghai Jiao Tong University
2022
Enhancement of polarization and related properties in heteroepitaxially constrained thin films the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that crystal structure film monoclinic contrast to bulk, which rhombohedral. The display a room-temperature spontaneous (50 60 microcoulombs per square centimeter) almost an order magnitude higher than bulk (6.1 centimeter). observed enhancement corroborated by first-principles calculations found originate from high...
We report on the coupling between ferroelectric and magnetic order parameters in a nanostructured BaTiO3-CoFe2O4 ferroelectromagnet. This facilitates interconversion of energies stored electric fields plays an important role many devices, including transducers, field sensors, etc. Such nanostructures were deposited single-crystal SrTiO3 (001) substrates by pulsed laser deposition from single Ba-Ti-Co-Fe-oxide target. The films are epitaxial in-plane as well out-of-plane with self-assembled...
The loss of sulfur cathode material as a result polysulfide dissolution causes significant capacity fading in rechargeable lithium/sulfur cells. Here, we use chemical approach to immobilize and lithium polysulfides via the reactive functional groups on graphene oxide. This enabled us obtain uniform thin (around tens nanometers) coating oxide sheets by simple reaction-deposition strategy subsequent low-temperature thermal treatment process. Strong interaction between or demonstrate cells with...
Understanding of colloidal nanocrystal growth mechanisms is essential for the syntheses nanocrystals with desired physical properties. The classical model monodisperse assumes a discrete nucleation stage followed by via monomer attachment, but has overlooked particle-particle interactions. Recent studies have suggested that interactions between particles play an important role. Using in situ transmission electron microscopy, we show platinum can grow either attachment from solution or...
The growth of colloidal nanocrystal architectures by nanoparticle attachment is frequently reported as an alternative to the conventional monomer attachment. However, mechanism whereby proceeds microscopically remains unclear. We report real-time transmission electron microscopy (TEM) imaging solution Pt(3)Fe nanorods from building blocks. Observations revealed winding polycrystalline chains shape-directed followed straightening and orientation shape corrections yield single-crystal...
A robust and efficient non-precious metal catalyst for hydrogen evolution reaction is one of the key components carbon dioxide-free production. Here we report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst able to produce from water under mild overpotential at more than twice rate state-of-the-art carbon-supported platinum catalyst. Although both copper titanium are known be poor catalysts, combination these two elements creates unique copper-copper-titanium hollow...
An understanding of how facets a nanocrystal develop is critical for controlling shape and designing novel functional materials. However, the atomic pathways facet development are mostly unknown because lack direct observation. We report imaging platinum nanocube growth in liquid cell using transmission electron microscopy with high spatial temporal resolution. The rates all low index similar until {100} stop growth. continuous rest leads to nanocube. Our calculation shows that much lower...
We present direct evidence for room-temperature magnetization reversal induced by an electric field in epitaxial ferroelectric BiFeO3-ferrimagnetic CoFe2O4 columnar nanostructures. Piezoelectric force microscopy and magnetic were used to locally image the coupled piezoelectric-magnetic switching. Quantitative analyses give a perpendicular magnetoelectric susceptibility of approximately 1.0 x 10(-2) G cm/V. The observed effect is due strong elastic coupling between two ferric constituents as...
We report solar cells based on highly confined nanocrystals of the ternary compound PbSxSe1-x. Crystalline, monodisperse alloyed are obtained using a one-pot, hot injection reaction. Rutherford back scattering and energy-filtered transmission electron microscopy suggest that S Se anions uniformly distributed in alloy nanoparticles. Photovoltaic devices made nanoparticles more efficient than either pure PbS or PbSe nanocrystal devices.
The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that the selectivity for take place at different facets plays an important role in determining resulting morphology binary heterostructure. In case copper(I) (Cu(+)) cadmium sulfide (CdS) nanorods, reaction starts preferentially ends nanorods such copper (Cu(2)S) grows inward from either end. is very striped pattern obtained our previous studies...
We report a detailed magnetic and structural analysis of highly reduced Co doped rutile TiO(2-delta) films displaying an anomalous Hall effect (AHE). The temperature field dependence magnetization, transmission electron microscopy, clearly establish the presence nanosized superparamagnetic cobalt clusters approximately 8-10 nm size in at interface. co-occurrence superparamagnetism AHE raises questions regarding use as test intrinsic nature ferromagnetism diluted semiconductors.
We report direct visualization of electrochemical lithiation and delithiation Au anodes in a commercial LiPF6/EC/DEC electrolyte for lithium ion batteries using transmission electron microscopy (TEM). The inhomogeneous lithiation, metal dendritic growth, decomposition, solid-electrolyte interface (SEI) formation are observed situ. These results shed lights on strategies improving electrode design reducing short-circuit failure the performance batteries.
We show that nanocrystals (NCs) with well-established synthetic protocols for high shape and size monodispersity can be used as templates to independently control the NC composition through successive cation exchange reactions. Chemical transformations like reactions overcome a limitation in traditional colloidal synthesis, where often reflects inherent symmetry of underlying lattice. Specifically we full or partial interconversion between wurtzite CdS, chalcocite Cu2S, rock salt PbS NCs...
3D heteroepitaxial growth of BiFeO3-CoFe2O4 nanostructures leads to unique morphological patterns depending on the substrate orientations. The morphologies nanostructures, estimated using Winterbottom construction (see figure), are dependent different nucleation modes that result from differences in surface energy anisotropy. dimensions increase as temperature increases and decrease rate increases.
We have directly observed motion of inorganic nanoparticles during fluid evaporation using a transmission electron microscope. Tracking real-time diffusion both spherical (5−15 nm) and rod-shaped (5 × 10 gold nanocrystals in thin film water−15% glycerol reveals complex movements, such as rolling motions coupled to large-step movements macroscopic violations the Stokes−Einstein relation for diffusion. As drying patches form final stages evaporation, particle is dominated by nearby retracting...
Abstract The design and fabrication of 2D nanostructure electrodes with desired electrochemical activities is highly demanded for electrocatalysis supercapacitors. Herein, the tuned ultrathin tortuous nickel/cobalt‐layered double hydroxide (NiCo‐LDH) nanosheets via a graphene oxide (GO) surface‐confined strategy reported, yielding thickness 1.7–1.8 nm that duplicated from oxides in terms both lateral size shape. It has been found C/O functional groups on GO surface have functioned to promote...
The study of first-order structural transformations has been great interest to scientists in many disciplines. Expectations from phase-transition theory are that the system fluctuates between two equilibrium structures near transition point and region broadens small crystals. We report direct observation fluctuations within a single nanocrystal using transmission electron microscopy. observed trajectories individual nanocrystals with atomic resolution, which reveal details fluctuation...
This paper investigates lithium-ion electrode laminates as polymer composites to explain their performance variation due changes in formulation. There are three essential components a positive laminate: active material (AM) particles, acetylene black (AB) and the binder. The high filler content discrete particle sizes make laminate very unique composite. work introduces physical model which AB AM particles compete for binder, forms fixed layers of on surfaces. competition leads observed...
A nitrogen-doped Co<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>@nanocarbon hybrid was developed as an oxygen reduction reaction (ORR) catalyst and exhibits outstanding catalytic performance with high activity, long-term stability a four-electron transfer pathway.
Inside a liquid solution, oriented attachment (OA) is now recognized to be as important pathway crystal growth other, more conventional mechanisms. However, the driving force that controls occurrence of OA still poorly understood. Here, using in-situ cell transmission electron microscopy, we demonstrate ligand-controlled citrate-stabilized gold nanoparticles at atomic resolution. Our data reveal particle pairs rotate randomly separation distance greater than twice layer thickness adsorbed...
A spongy nickel-organic photocatalyst with nearly 100% selective CO 2 to conversion.