A5041326018- Graphene research and applications
- Machine Learning in Materials Science
- 2D Materials and Applications
- Electrocatalysts for Energy Conversion
- Advancements in Battery Materials
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Fuel Cells and Related Materials
- Catalytic Processes in Materials Science
- Advanced Battery Materials and Technologies
- nanoparticles nucleation surface interactions
- Advanced Chemical Physics Studies
- Diamond and Carbon-based Materials Research
- Advanced Battery Technologies Research
- University-Industry-Government Innovation Models
- Electronic and Structural Properties of Oxides
- Quantum chaos and dynamical systems
- Perovskite Materials and Applications
- Molecular Junctions and Nanostructures
- Advanced Photocatalysis Techniques
- MXene and MAX Phase Materials
- Catalysis and Hydrodesulfurization Studies
- Surface Chemistry and Catalysis
- Supramolecular Self-Assembly in Materials
- Copper-based nanomaterials and applications
Harvard University
2012-2023
Harvard University Press
2014
Peking University
2013
Technical University of Denmark
2011-2012
SLAC National Accelerator Laboratory
2011
University of Patras
2010
Debre Tabor University
2010
Electronic structure calculations have become an indispensable tool in many areas of materials science and quantum chemistry. Even though the Kohn-Sham formulation density-functional theory (DFT) simplifies many-body problem significantly, one is still confronted with several numerical challenges. In this article we present projector augmented-wave (PAW) method as implemented GPAW program package (https://wiki.fysik.dtu.dk/gpaw) using a uniform real-space grid representation electronic...
The energy density of Li-ion batteries depends critically on the specific charge capacity constituent electrodes. Silicene, silicon analogue to graphene, being atomic thickness could serve as high-capacity host Li in secondary batteries. In this work, we employ first-principles calculations investigate interaction with Si model electrodes free-standing single-layer and double-layer silicene. More specifically, identify strong binding sites for Li, calculate barriers accompanying diffusion,...
We present an accurate \textit{ab-initio} tight-binding hamiltonian for the transition-metal dichalcogenides, MoS$_2$, MoSe$_2$, WS$_2$, WSe$_2$, with a minimal basis (the \textit{d} orbitals metal atoms and \textit{p} chalcogen atoms) based on transformation of Kohn-Sham density function theory (DFT) to maximally localized Wannier functions (MLWF). The truncated (TBH), only on-site, first partial second neighbor interactions, including spin-orbit coupling, provides simple physical picture...
The rate performance of lithium-ion secondary batteries depends critically on the kinetic transport Li within anode material. Here we use first-principles theoretical calculations to study diffusion in low-concentration limit, using model electrodes crystalline and four-fold coordinated bulk amorphous silicon. We identify pathways that have relatively low energy barriers (<0.50 eV) silicon discuss how at short (∼2.5 Å), intermediate (∼10 long (>1 nm) distances atomic-scale features host....
In the search for high-energy density materials Li-ion batteries, silicon has emerged as a promising candidate anodes due to its ability absorb large number of Li atoms. Lithiation Si leads deformation and concurrent changes in mechanical properties, from brittle material pure form that can sustain inelastic lithiated form. These remarkable behavior pose challenge theoretical treatment properties. Here, we provide detailed picture origin based on first-principles calculations atomic-scale...
Using the binding energy of OH* and CO* on close-packed surfaces as reactivity descriptors, we screen bulk surface alloy catalysts for methanol electro-oxidation activity. these two illustrate that a good catalyst must have three key properties: (1) ability to activate methanol, (2) water, (3) react off intermediates (such OH*). Based this analysis, an made up Cu Pt should synergistic effect facilitating activity towards electro-oxidation. PtCu3 is proposed best catalytic properties Pt–Cu...
SnS is a metal monochalcogenide suitable for use as absorber material in thin film photovoltaic cells. Its structure an orthorhombic crystal of weakly coupled layers, each layer consisting strongly bonded Sn-S units. We first-principles calculations to study model single-layer, double-layer, and bulk structures order elucidate its electronic structure. find that the optoelectronic properties can vary significantly with respect number layers separation between them: calculated band gap wider...
The ability to fabricate 2D device architectures with desired properties, based on stacking of weakly (van der Waals) interacting atomically thin layers, is quickly becoming reality. In order design ever more complex devices this type, it crucial know the precise strain and composition dependence layers' electronic optical properties. Here, we present a theoretical study these dependences for monolayers compositions varying from pure ${MX}_{2}$ mixed $MXY$, where $M=\text{Mo}$, W...
Silicon (Si) has been recognized as a promising anode material for the next-generation high-capacity lithium (Li)-ion batteries because of its high theoretical energy density. Recent in situ transmission electron microscopy (TEM) revealed that electrochemical lithiation crystalline Si nanowires (c-SiNWs) proceeds by migration interface between lithiated (LixSi) shell and pristine unlithiated core, accompanied solid-state amorphization. The underlying atomic mechanisms Li insertion into c-Si...
Direct methanol fuel cells are a key enabling technology for clean energy conversion. Using density functional theory calculations, we study the oxidation reaction on model electrodes. We discuss trends in reactivity set of monometallic and bimetallic transition metal surfaces, flat stepped, which includes platinum-based alloys with ruthenium, tin, copper, as well nonprecious alloys, overlayer structures, modified edges. A common lower bound overpotential is estimated (ca. 0.3 V)....
Two-dimensional (2D) materials are a promising candidate for the anode material of lithium-ion battery (LIB) and sodium-ion (NIB) their unique physical chemical properties. Recently, honeycomb borophene ( h -borophene) has been fabricated by molecular beam epitaxy (MBE) growth in ultra high vacuum. Here, we adopt first-principles density functional theory calculations to study performance monolayer (ML) -borophene as an LIB NIB. The binding energies ML -borophene-Li/Na systems all negative,...
Light-driven chemical reactions on semiconductor surfaces have potential for addressing energy and pollution needs through efficient synthesis; however, little is known about the time evolution of excited states that determine reaction pathways. Here, we study photo-oxidation methoxy (CH3O) derived from methanol rutile TiO2(110) surface using ab initio simulations to create a molecular movie process. The sequence reveals wealth information intermediates, scales, energetics. broken in three...
Adsorption energies on surfaces are excellent descriptors of their chemical properties, including catalytic performance. High-throughput adsorption energy predictions can therefore help accelerate first-principles catalyst design. To this end, we present over 5000 DFT calculations H dilute Ag alloys and describe a general machine learning approach to rapidly predict for new alloy structures. We find that random forests provide accurate the best features combinations traditional structural...
Quantum confinement endows two-dimensional (2D) layered materials with exceptional physics and novel properties compared to their bulk counterparts. Although certain two- few-layer configurations of graphene have been realized studied, a systematic investigation the arbitrarily assemblies is still lacking. We introduce theoretical concepts methods for processing information, as case study, apply them investigate electronic structure multi-layer graphene-based in high-throughput fashion....
We investigate the effects of lithium intercalation in twisted bilayers graphene, using first-principles electronic structure calculations. To model this system we employ commensurate supercells that correspond to twist angles 7.34$^\circ$ and 2.45$^\circ$. From energetics absorption demonstrate for low Li concentration intercalants cluster AA regions with double density a uniform distribution. The charge donated by atoms graphene layers results modifications band can be qualitatively...
Hydrogen production in photoelectrochemical cells constitutes an important avenue toward carbon-free fuel. The most convenient process for hydrogen is the splitting of water molecules, which necessitates a catalytic reaction involving semiconductor. Here, we introduce framework study photocatalyzed reactions on semiconductor surfaces based time-dependent density functional theory that explicitly accounts evolution electronically excited states. Within this framework, investigate possibility...
A key issue in layered materials is the dependence of their properties on chemical composition and crystal structure addition to dimensionality. For instance, atomically thin magnetic structures exhibit novel spin that do not exist bulk. We use first-principles calculations, based density functional theory, machine learning study magnetocrystalline anisotropy a set single-layer two-dimensional are derived from changing ferromagnetic semiconductor Cr2Ge2Te6. discuss trends identify...
Thin film photovoltaic cells are increasingly important for cost-effective solar energy harvesting. Layered SnS is a promising absorber material due to its high optical absorption in the visible and good doping characteristics. We use first-principles calculations based on density functional theory study structures of low-index surfaces using stoichiometric oxygen-containing structural models, order elucidate their possible effect efficiency device. find that surface minimized with...
A tough material commonly used in coatings is diamond-like carbon (DLC), that is, amorphous with content four-fold coordinated C higher than ∼70%, and its composites metal inclusions. This study aims to offer useful guidelines for the design development of metal-containing DLC solar collectors, where efficiency collector depends critically on performance absorber coating. We use first-principles calculations based density functional theory structural, electronic, optical, elastic properties...
Two-dimensional (2D) layered materials, demonstrating significantly different properties from their bulk counterparts, offer a materials platform with potential applications energy to information processing devices. Although some single- and few-layer forms of such as graphene transition metal dichalcogenides have been realized thoroughly studied, the space arbitrarily assemblies is still mostly unexplored. The main goal this work demonstrate precise control materials' electronic through...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Adsorption and Diffusion of Lithium on Layered Silicon for Li-Ion StorageGeorgios A. Tritsaris, Efthimios Kaxiras, Sheng Meng*, Enge WangCite this: Nano Lett. 2013, 13, 6, 3004Publication Date (Web):May 24, 2013Publication History Published online24 May 2013Published inissue 12 June 2013https://pubs.acs.org/doi/10.1021/nl4018644https://doi.org/10.1021/nl4018644correctionACS...
Recent experiments have revealed ripplocations, atomic-scale ripplelike defects on samples of MoS2 flakes. We use quantum mechanical calculations based density functional theory to study the effect ripplocations structural and electronic properties single-layer MoS2, and, in particular, coupling between these extended most common this material, S-vacancies. find that formation neutral S-vacancies is energetically more favorable ripplocation. In addition, we demonstrate alone do not introduce...