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General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Etats électroniques, Electron states, Méthodes de calcul de structure électronique, Methods of electronic structure calculations, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Structure électronique des nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals, Doubles couches superficielles, barrières de schottky et travail de sortie, Surface double layers, schottky barriers, and work functions, Transport électronique dans des structures à interface, Electronic transport in interface structures, Résistance de contact, potentiel de contact, Contact resistance, contact potential, Ancrage, Pinning, Barrière Schottky, Schottky barriers, Contact ohmique, Ohmic contacts, Couche monomoléculaire, Monolayers, Etat défaut, Defect states, Etude théorique, Theoretical study, Interface, Interfaces, Jonction à semiconducteur, Semiconductor junctions, Métal complexe, Metal complex, Metal complejo, Méthode fonctionnelle densité, Density functional method, Niveau Fermi, Fermi level, Platine, Platinum, Semiconducteur, Semiconductor materials, Structure électronique, Electronic structure, Travail sortie, Work functions, 7115M, 7340C, and MoS2

Density functional theory calculations are performed to unravel the nature of the contact between metal electrodes and monolayer MoS2. Schottky barriers are shown to be present for a variety of metals with the work functions spanning over 4.2-6.1 eV. Except for the p-type Schottky contact with platinum, the Fermi levels in all of the studied metal-MoS2 complexes are situated above the midgap of MoS2. The mechanism of the Fermi level pinning at metal― MoS2 contact is shown to be unique for metal―2D-semiconductor interfaces, remarkably different from the well-known Bardeen pinning effect, metal-induced gap states, and defect/disorder induced gap states, which are applicable to traditional metal―semiconductor junctions. At metal―MoS2 interfaces, the Fermi level is partially pinned as a result of two interface behaviors: first by a metal work function modification by interface dipole formation due to the charge redistribution, and second by the production of gap states mainly of Mo d-orbitals character by the weakened intralayer S―Mo bonding due to the interface metal―S interaction. This finding would provide guidance to develop approaches to form Ohmic contact to MoS2. KEYWORDS: MoS2, metal contact, Fermi level pinning, Schottky barrier, work function, density functional theory (DFT).

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Etats électroniques, Electron states, Méthodes de calcul de structure électronique, Methods of electronic structure calculations, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Aberration, Aberrations, Carbone, Carbon, Etude théorique, Theoretical study, Graphène, Graphene, Lacune, Vacancies, Microscopie électronique transmission, Transmission electron microscopy, Méthode dynamique moléculaire, Molecular dynamics method, Méthode fonctionnelle densité, Density functional method, Structure défaut, Defect structure, 7115M, 8105T, and 8105U

Vacancy defects in graphene with an odd number of missing atoms, such as the trivacancy, have been imaged at atomic resolution using aberration corrected transmission electron microscopy. These defects are not just stabilized by simple bond reconstructions between under-coordinated carbon atoms, as exhibited by even vacancies such as the divacancy. Instead we have observed reconstructions consisting of under-coordinated bridging carbon atoms spanning the vacancy to saturate edge atoms. We report detailed studies of the effect of this bridging atom on the configuration of the trivacancy and higher order odd number vacancies, as well as its role in defect stabilization in amorphous systems. Theoretical analysis using density functional theory and tight-binding molecular dynamics calculations demonstrate that the bridging atom enables the low energy reconfiguration of these defect structures.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Fils quantiques, Quantum wires, Méthodes de nanofabrication, Methods of nanofabrication, Méthodes de synthèse chimique, Chemical synthesis methods, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Croissance cristalline, Crystal growth, Diffusion(transport), Diffusion, Dispositif nanofil, Nanowire device, Dispositivo nanohilo, Dépôt électrolytique, Electrodeposition, Gradient température, Temperature gradients, Instabilité, Instability, Matériau poreux, Porous materials, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Méthode contrôle, Control method, Método control, Nanofil, Nanowires, Nanomatériau, Nanostructured materials, Nanotechnologie, Nanotechnology, Processus diffusion, Diffusion process, Proceso difusión, Réaction dirigée, Template reaction, Reacción dirigida, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, 8107B, 8107V, and 8116B

The incomplete growth of nanowires that are synthesized by template-assisted electrodeposition presents a major challenge for nanowire-based devices targeting energy and electronic applications. In template-assisted electrodeposition, the growth of nanowires in the pores of the template is complex and unstable. Here we show theoretically and experimentally that the dynamics of this process is diffusion-limited, which results in a morphological instability driven by a race among nanowires. Moreover, we use our findings to devise a method to control the growth instability. By introducing a temperature gradient across the porous template, we manipulate ion diffusion in the pores, so that we can reduce the growth instability. This strategy significantly increases the length of nanowires. In addition to shedding light on a key nanotechnology, our results may provide fundamental insights into a variety of interfacial growth processes in materials science such as crystal growth and tissue growth in scaffolds.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Autres, Others, Application médicale, Medical application, Aplicación medical, Cellule animale, Animal cells, Facteur croissance, Growth factor, Factor crecimiento, Homme, Human, Hombre, Relation symbiotique, Symbiotic relation, and Relación simbiótica

To construct an intracellular machine, we sought a symbiotic relationship between a photosynthetic green alga and human cells. Human cells selectively take up the minimal eukaryote Nannochloris eukaryotum and the resulting symbionts are able to survive and proliferate. Host cells can utilize N. eukaryotum's photosynthetic apparatus for survival, and expression of cellular vascular endothelial growth factor can be controlled with input of photonic energy. This seemingly rare spontaneous association provides an opportunity to fabricate light-controlled, intracellular machines.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des nanostructures et des nanomatériaux, Mechanical properties of nanoscale materials, Propriétés de transport (non électroniques), Transport properties of condensed matter (nonelectronic), Diffusion dans les solides, Diffusion in solids, Diffusion dans les nanomatériaux et nanostructures, Diffusion in nanoscale solids, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structures de basse dimensionnalité (superréseaux, puits quantiques, multicouches): structure et propriétés non électroniques, Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de nanofabrication, Methods of nanofabrication, Formation de nanomotifs, Nanoscale pattern formation, Adhérence, Adhesion, Cellule souche, Stem cells, Diffusion(transport), Diffusion, Echelle nanométrique, Nanometer scale, Formation motif, Patterning, Formation nanomotif, Nanopatterning, Formacíon nanomotivo, Hydrogel, Hidrogel, Macromolécule, Macromolecules, Microscopie électronique balayage transmission, Scanning transmission electron microscopy, Nanocommande, Nanocontrol, Nanostructure, Nanostructures, Propriété mécanique, Mechanical properties, Protéine, Proteins, Tribologie, Tribology, 6630P, and 8116R

We show that the nanoscale adhesion geometry controls the spreading and differentiation of epidermal stem cells. We find that cells respond to such hard nanopatterns similarly to their behavior on soft hydrogels. Cellular responses were seen to stem from local changes in diffusion dynamics of the adapter protein vinculin and associated impaired mechanotransduction rather than impaired recruitment of proteins involved in focal adhesion formation.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des nanostructures et des nanomatériaux, Mechanical properties of nanoscale materials, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structures de basse dimensionnalité (superréseaux, puits quantiques, multicouches): structure et propriétés non électroniques, Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Adhérence, Adhesion, Cale espacement, Spacer, Calce espaciamiento, Dispositif 1molécule, Single molecule device, Dispositivo 1 molécula, Echelle nanométrique, Nanometer scale, Effet contrainte, Stress effects, Electronique moléculaire, Molecular electronics, Fibroblaste, Fibroblasts, Formation image, Imaging, Gravure, Etching, Nanostructure, Nanostructures, Ouverture optique, Aperture, Abertura óptica, Petite ouverture, Apertures, Propriété mécanique, Mechanical properties, Réseau(arrangement), Arrays, Tribologie, and Tribology

The combination of micropillar array technology to measure cellular traction forces with super-resolution imaging allowed us to obtain cellular traction force maps and simultaneously zoom in on individual focal adhesions with single-molecule accuracy. We achieved a force detection precision of 500 pN simultaneously with a mean single-molecule localization precision of 30 nm. Key to the achievement was a two-step etching process that provided an integrated spacer next to the micropillar array that permitted stable and reproducible observation of cells on micropillars within the short working distance of a high-magnification, high numerical aperture objective. In turn, we used the technology to characterize the super-resolved structure of focal adhesions during force exertion. Live-cell imaging on MCF-7 cells demonstrated the applicability of the inverted configuration of the micropillar arrays to dynamics measurements. Forces emanated from a molecular base that was localized on top of the micropillars. What appeared as a single adhesion in conventional microscopy were in fact multiple elongated adhesions emanating from only a small fraction of the adhesion on the micropillar surface. Focal adhesions were elongated in the direction of local cellular force exertion with structural features of 100—280 nm in 3T3 Fibroblasts and MCF-7 cells. The combined measure of nanoscale architecture and force exerted shows a high level of stress accumulation at a single site of adhesion.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Diffraction et diffusion de rayons x, X-ray diffraction and scattering, Diffusion rx (incluant la diffusion aux petits angles), X-ray scattering (including small-angle scattering), Nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Diamant, Diamonds, Diffusion RX centrale, Small angle X ray scattering, Difusión rayo X central, Echelle nanométrique, Nanometer scale, Etude théorique, Theoretical study, Interaction moléculaire, Molecular interaction, Interacción molecular, Longueur chaîne, Chain length, Longitud cadena, Molécule organique, Organic molecule, Molécula orgánica, Méthode fonctionnelle densité, Density functional method, Nanocristal, Nanocrystal, Nanomatériau, Nanostructured materials, Superréseau, Superlattices, 6110E, 8105U, 8107B, and PbS

Ordered assemblies of inorganic nanocrystals coated with organic linkers present interesting scientific challenges in hard and soft matter physics. We demonstrate that a nanocrystal superlattice under compression serves as a nanoscopic pressure cell to enable studies of molecular linkers under uniaxial compression. We developed a method to uniaxially compress the bifunctional organic linker by attaching both ends of aliphatic chains to neighboring PbS nanocrystals in a superlattice. Pressurizing the nanocrystal superlattice in a diamond anvil cell thus results in compression of the molecular linkers along their chain direction. Small-angle and wide-angle X-ray scattering during the compression provide insights into the structure of the superlattice and nanocrystal cores under compression, respectively. We compare density functional theory calculations of the molecular linkers as basic Hookean springs to the experimental force―distance relationship. We determine the density of linkers on the nanocrystal surfaces. We demonstrate our method to probe the elastic force of single molecule as a function of chain length. The methodology introduced in this paper opens doors to investigate molecular interactions within organic molecules compressed within a nanocrystal superlattice.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Etats électroniques de surface et d'interface, Surface and interface electron states, Excitations collectives (incluant excitons, polarons, plasmons et autres excitations de densité de charge), Collective excitations (including excitons, polarons, plasmons and other charge-density excitations), Emissions électronique et ionique; phénomènes d'impact, Electron and ion emission by liquids and solids; impact phenomena, Photoémission et spectres photoélectroniques, Photoemission and photoelectron spectra, Interfaces, hétérostructures, nanostructures, Interfaces, heterostructures, nanostructures, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Dispersion, Dispersions, Dépendance temps, Time dependence, Interaction plasmon polariton, Plasmon polariton interaction, Interacción plasmón polaritón, Microscopie électronique, Electron microscopy, Nanoélectronique, Nanoelectronics, Onde surface, Surface waves, Photoémission, Photoemission, Plasmon surface, Surface plasmons, Résolution temporelle, Time resolution, Spectre résolution temporelle, Time resolved spectra, Temps réel, Real time, Tiempo real, 7320M, 7960J, Nanoantenne, Nanoantenna, and Nanoantena

In this work, the mutual coupling and coherent interaction of propagating and localized surface plasmons within a model-type plasmonic assembly is experimentally demonstrated, imaged, and analyzed. Using interferometric time-resolved photoemission electron microscopy the interplay between ultrashort surface plasmon polariton wave packets and plasmonic nanoantennas is monitored on subfemtosecond time scales. The data reveal real-time insights into dispersion and localization of electromagnetic fields as governed by the elementary modes determining the functionality of plasmonic operation units.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Transport électronique dans les multicouches, nanomatériaux et nanostructures, Electronic transport in multilayers, nanoscale materials and structures, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Méthodes de nanofabrication, Methods of nanofabrication, Addition iode, Iodine additions, Conductivité électrique, Electrical conductivity, Conversion thermoélectrique, Thermoelectric conversion, Conversion énergie, Energy conversion, Couche mince, Thin films, Dispositif thermoélectrique, Thermoelectric devices, Dopage, Doping, Dépôt immersion, Dip coating, Effet Seebeck, Seebeck effect, Effet concentration, Quantity ratio, Nanocristal, Nanocrystal, Nanomatériau, Nanostructured materials, Procédé sol gel, Sol-gel process, Propriété électrique, Electrical properties, Précurseur, Precursor, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, 8107B, and Substrat verre

For the first time, we demonstrate a successful synthesis of colloidal n-type lead telluride nanocrystals doped with iodine. By tuning the reaction time and iodine concentration in the precursor solution, nanocrystals with different sizes and doping concentrations are synthesized. The Seebeck coefficient and electrical conductivity of the nanocrystals are measured on nanocrystal thin films fabricated by dip-coating glass substrates in the nanocrystals solution. Investigations on the influence of size and doping concentration on the electrical properties have been performed. The results show that the size of the nanocrystals significantly influences the electrical conductivity but not the Seebeck coefficient of nanocrystal films, while higher doping concentration leads to lower Seebeck coefficient but higher electrical conductivity in the nanocrystal films. Proof-of-concept thin-film thermoelectric modules are also fabricated using both p-type and n-type PbTe nanocrystals for the conversion of thermal energy into electrical energy.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Transformations de phases particulières, Specific phase transitions, Transitions dans les nanostructures et nanomatériaux, Structural transitions in nanoscale materials, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Méthodes de nanofabrication, Methods of nanofabrication, Méthodes de synthèse chimique, Chemical synthesis methods, Carbone, Carbon, Fullerènes, Fullerenes, Microscopie tunnel balayage, Scanning tunneling microscopy, Quasicristal, Quasicrystals, Relation ordre, Ordering, Relación orden, Réaction dirigée, Template reaction, Reacción dirigida, Transformation ordre désordre, Order-disorder transformations, 6470N, 8105T, 8105U, 8116B, C60, Substrat Aluminium, Substrat cuivre, and Substrat quasicristal

Quasicrystals are materials with long-range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on 5-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently separated Fe atoms on icosahedral Al—Cu—Fe to form a unique quasicrystalline lattice, whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at 10-fold symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag—In—Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Méthodes de nanofabrication, Methods of nanofabrication, Méthodes de synthèse chimique, Chemical synthesis methods, Autoassemblage, Self-assembly, Autoassemblage, Self-assembly, Dose, Doses, Microparticule, Microparticles, Méthode Monte Carlo, Monte Carlo methods, Nanomatériau, Nanostructured materials, Nanoparticule, Nanoparticles, Or, Gold, Paramètre cristallin, Lattice parameters, Relation ordre, Ordering, Relación orden, Réaction dirigée, Template reaction, Reacción dirigida, Réseau(arrangement), Arrays, Structure cristalline, Crystal structure, Transformation ordre désordre, Order-disorder transformations, 8107B, 8116B, and 8116D

We report on the directed self-assembly of sub-10 nm gold nanoparticles confined within a template comprising channels of gradually varying widths. When the colloidal lattice parameter is mismatched with the channel width, the nanoparticles rearrange and break their natural dose-packed ordering, transiting through a range of structural configurations according to the constraints imposed by the channel While much work has been done in assembling ordered configurations, studies of the transition regime between ordered states have been limited to microparticles under applied compression. Here, with coordinated experiments and Monte Carlo simulations we show that particles transit through a more diverse set of self-assembled configurations than observed for compressed systems. The new insight from this work could lead to the control and design of complex self-assembled patterns other than periodic arrays of ordered particles.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Conversion énergie, Energy conversion, Conversión energética, Effet redresseur, Rectifier effect, Efecto rectificador, Nanoélectronique, Nanoelectronics, Nanoelectrónica, Redresseur, Rectifier, Rectificador, Résistance électrique, Resistor, Resistencia eléctrica(componente), Traitement thermique, Heat treatment, and Tratamiento térmico

Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the Rectifier state, we observe up to 28% thermal rectification. In the Resistor state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Transport électronique dans les multicouches, nanomatériaux et nanostructures, Electronic transport in multilayers, nanoscale materials and structures, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Méthodes de nanofabrication, Methods of nanofabrication, Arséniure d'indium, Indium arsenides, Composé III-V, III-V compound, Compuesto III-V, Couche mince, Thin films, Dopage, Doping, Dépendance température, Temperature dependence, Effet Hall, Hall effect, Effet température, Temperature effects, Etude comparative, Comparative study, Estudio comparativo, Ligand, Ligands, Mobilité Hall, Hall mobility, Métal complexe, Metal complex, Metal complejo, Nanocristal, Nanocrystal, Nanomatériau, Nanostructured materials, Propriété électrique, Electrical properties, Réseau(arrangement), Arrays, Semiconducteur III-V, III-V semiconductors, Sulfure de cuivre, Copper sulfide, Cobre sulfuro, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, Transport charge, Charge transport, 8107B, and Cu7S4

We report on the temperature-dependent Hall effect characteristics of nanocrystal (NC) arrays prepared from colloidal InAs NCs capped with metal chalcogenide complex (MCC) ligands (In2Se42- and Cu7S4-). Our study demonstrates that Hall effect measurements are a powerful way of exploring the fundamental properties of NC solids. We found that solution-cast 5.3 nm InAs NC films capped with copper sulfide MCC ligands exhibited high Hall mobility values over 16 cm2/(V s). We also showed that the nature of MCC ligands can control doping in NC solids. The comparative study of the temperature-dependent Hall and field-effect mobility values provides valuable insights concerning the charge transport mechanism and points to the transition from a weak to a strong coupling regime in all-inorganic InAs NC solids.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Dynamique réticulaire, Lattice dynamics, Phonons dans les structures de basse dimensionnalité et dans les particules fines, Phonons in low-dimensional structures and small particles, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Bicouche, Bilayers, Chauffage laser, Laser-radiation heating, Dépendance température, Temperature dependence, Déplacement raie, Spectral line shift, Déplacement vers le rouge, Red shift, Désorption, Desorption, Epaisseur couche, Layer thickness, Espesor capa, Graphène, Graphene, Mode vibration, Vibrational modes, Spectrométrie Raman, Raman spectroscopy, Vibration, Vibrations, 8105T, 8105U, and Substrat graphène

We investigated the low-frequency Raman spectra of freestanding few-layer graphene (FLG) at varying temperatures (400―900 K) controlled by laser heating. At high temperature, we observed the fundamental Raman mode for the lowest-frequency branch of rigid-plane layer-breathing mode (LBM) vibration. The mode frequency redshifts dramatically from 81 cm -1 for bilayer to 23 cm-1 for 8-layer. The thickness dependence is well described by a simple model of coupled oscillators. Notably, the LBM Raman response is unobservable at room temperature, and it is turned on at higher temperature (>600 K) with a steep increase of Raman intensity. The observation suggests that the LBM vibration is strongly suppressed by molecules adsorbed on the graphene surface but is activated as desorption occurs at high temperature.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des structures de basse dimensionnalité, mésoscopiques, des nanostructures et nanomatériaux, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Points quantiques, Quantum dots, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Commutation, Switching, Facteur mérite, Figure of merit, Factor mérito, Loi Gauss, Gaussian distribution, Loi normale, Normal distribution, Mesure électrique, Electrical measurement, Medida eléctrica, Nanomatériau, Nanostructured materials, Photoluminescence, Piégeage, Trapping, Point quantique, Quantum dots, Structure coeur couche, Core shell structure, 8107B, 8107T, 8535B, CdS, CdSe, Structure coeur coque, and Estructura núcleo cascarón

We report measurements of electrical transport through single CdSe/CdS core/shell colloidal quantum dots (cQDs) connected to source and drain contacts. We observe telegraphic switching noise showing few plateaus at room temperature. We model and interpret these results as charge trapping of individual trap states, and therefore we resolve individual charge defects in these high-quality low-strain cQDs. The small number of observed defects quantitatively validates the passivation method based on thick CdS shells nearly lattice-matched to CdSe cores first developed to suppress photoluminescence blinking. Finally, we introduce a figure of merit useful to efficiently distinguish telegraphic noise from noise with a Gaussian distribution.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Dynamique réticulaire, Lattice dynamics, Phonons dans les structures de basse dimensionnalité et dans les particules fines, Phonons in low-dimensional structures and small particles, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Etats électroniques, Electron states, Méthodes de calcul de structure électronique, Methods of electronic structure calculations, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des structures de basse dimensionnalité, mésoscopiques, des nanostructures et nanomatériaux, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Méthodes de nanofabrication, Methods of nanofabrication, Autoassemblage, Self-assembly, Conductivité électrique, Electrical conductivity, Couche autoassemblée, Self-assembled layers, Couche monomoléculaire, Monolayers, Densité défaut, Defect density, Densidad defecto, Dépendance température, Temperature dependence, Interface, Interfaces, Mesure température, Temperature measurement, Mesure électrique, Electrical measurement, Medida eléctrica, Molybdène, Molybdenum, Monocristal, Monocrystals, Méthode fonctionnelle densité, Density functional method, Phonon, Phonons, Photoluminescence, Polarité, Polarity, Polaridad, Propriété optique, Optical properties, Propriété physique, Physical properties, Propriété électrique, Electrical properties, Transfert charge, Charge transfer, Transferencia carga, 7115M, 8116D, and MoS2

We demonstrate how substrate interfacial chemistry can be utilized to tailor the physical properties of single-crystalline molybdenum disulfide (MoS,) atomic-layers. Semiconducting, two-dimensional MoS2 possesses unique properties that are promising for future optical and electrical applications for which the ability to tune its physical properties is essential. We use self-assembled monolayers with a variety of end termination chemistries to functionalize substrates and systematically study their influence on the physical properties of MoS2. Using electrical transport measurements, temperature-dependent photoluminescence spectroscopy, and empirical and first-principles calculations, we explore the possible mechanisms involved. Our data shows that combined interface-related effects of charge transfer, built-in molecular polarities, varied densities of defects, and remote interfacial phonons strongly modify the electrical and optical properties of MoS2. These findings can be used to effectively enhance or modulate the conductivity, field-effect mobility, and photoluminescence in MoS2 monolayers, illustrating an approach for local and universal property modulations in two-dimensional atomic-layers.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structures de basse dimensionnalité (superréseaux, puits quantiques, multicouches): structure et propriétés non électroniques, Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Méthodes de nanofabrication, Methods of nanofabrication, Autoassemblage, Self-assembly, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Electronique moléculaire, nanoélectronique, Molecular electronics, nanoelectronics, Arséniure de gallium, Gallium arsenides, Autoassemblage, Self-assembly, Bande interdite, Energy gap, Cellule photovoltaïque, Photovoltaic cells, Circuit intégré, Integrated circuits, Composé III-V, III-V compound, Compuesto III-V, Dislocation, Dislocations, Dispositif photovoltaïque, Photovoltaic cell, Dispositivo fotovoltaico, Echelle nanométrique, Nanometer scale, Hétérostructure, Heterostructures, Loi échelle, Scaling laws, Monocristal, Monocrystals, Mécanisme croissance, Growth mechanism, Mecanismo crecimiento, Nanoaiguille, Nanoneedle, Nanoaguja, Nanomatériau, Nanostructured materials, Nanostructure, Nanostructures, Perfection cristalline, Crystal perfection, Perfección cristalina, Phase cristalline, Crystalline phase, Fase cristalina, Rendement quantique, Quantum yield, Semiconducteur III-V, III-V semiconductors, Synthèse nanomatériau, Nanomaterial synthesis, Síntesis nanomaterial, 8107B, 8116D, InP, and Substrat silicium

Nanoscale self-assembly offers a pathway to realize heterogeneous integration of III-V materials on silicon. However, for III-V nanowires directly grown on silicon, dislocation-free single-crystal quality could only be attained below certain critical dimensions. We recently reported a new approach that overcomes this size constraint, demonstrating the growth of single-crystal InGaAs/GaAs and InP nanoneedles with the base diameters exceeding 1 μm. Here, we report distinct optical characteristics of InP nanoneedles which are varied from mostly zincblende, zincblende/wurtzite-mixed, to pure wurtzite crystalline phase. We achieved, for the first time, pure single-crystal wurtzite-phase InP nanoneedles grown on silicon with bandgaps of 80 meV larger than that of zincblende-phase InP. Being able to attain excellent material quality while scaling up in size promises outstanding device performance of these nanoneedles. At room temperature, a high internal quantum efficiency of 25% and optically pumped lasing are demonstrated for single nanoneedle as-grown on silicon substrate. Recombination dynamics proves the excellent surface quality of the InP nanoneedles, which paves the way toward achieving multijunction photovoltaic cells, long-wavelength heterostructure lasers, and advanced photonic integrated circuits.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Structure électronique et propriétés électriques des surfaces, interfaces, couches minces et structures de basse dimensionnalité, Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures, Structure électronique des nanomatériaux : agrégats, nanoparticules, nanotubes et nanocristaux, Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Propriétés optiques des structures de basse dimensionnalité, mésoscopiques, des nanostructures et nanomatériaux, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures, Angle torsion, Twist angle, Angulo torsión, Bicouche, Bilayers, Couche intermédiaire, Interlayers, Couche monomoléculaire, Monolayers, Etude théorique, Theoretical study, Génération harmonique 2, Second harmonic generation, Hétérostructure, Heterostructures, Mode empilement, Stacking sequence, Modo apilamiento, Molybdène, Molybdenum, Monocristal, Monocrystals, Propriété optique, Optical properties, Spectrométrie Raman, Raman spectroscopy, Structure cristalline, Crystal structure, Structure électronique, Electronic structure, Transition optique, Optical transition, and Transición óptica

Molybdenum disulfide bilayers with well-defined interlayer twist angle were constructed by stacking single-crystal monolayers. Varying interlayer twist angle results in strong tuning of the indirect optical transition energy and second-harmonic generation and weak tuning of direct optical transition energies and Raman mode frequencies. Electronic structure calculations show the interlayer separation changes with twist due to repulsion between sulfur atoms, resulting in shifts of the indirect optical transition energies. These results show that interlayer alignment is a crucial variable in tailoring the properties of two-dimensional heterostructures.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Etudes de matériaux magnétiques particuliers, Studies of specific magnetic materials, Particules fines, nanomatériaux, Small particles and nanoscale materials, Antibiotique, Antibiotics, Bactérie, Bacteria, Dispositif magnétique, Magnetic devices, Escherichia coli, Ligand, Ligands, Microfluidique, Microfluidics, Nanomatériau magnétique, Magnetic nanomaterial, Nanomaterial magnético, Particule magnétique, Magnetic particles, and 7550T

Bacterial sepsis is a serious clinical condition that can lead to multiple organ dysfunction and death despite timely treatment with antibiotics and fluid resuscitation. We have developed an approach to clearing bacteria and endotoxin from the bloodstream, using magnetic nanoparticles (MNPs) modified with bis-Zn-DPA, a synthetic ligand that binds to both Gram-positive and Gram-negative bacteria. Magnetic microfluidic devices were used to remove MNPs bound to Escherichia coli, a Gram-negative bacterium commonly implicated in bacterial sepsis, from bovine whole blood at flows as high as 60 mL/h, resulting in almost 100% clearance. Such devices could be adapted to clear bacteria from septicemic patients.

General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Dispositifs optoélectroniques, Optoelectronic devices, Energie, Energy, Energie naturelle, Natural energy, Energie solaire, Solar energy, Conversion photovoltaïque, Photovoltaic conversion, Cellules solaires. Cellules photoélectrochimiques, Solar cells. Photoelectrochemical cells, Cellule solaire, Solar cells, Conductivité type p, P type conductivity, Conductividad tipo p, Diode électroluminescente organique, Organic light emitting diodes, Dispositif optoélectronique, Optoelectronic devices, Ligand, Ligands, Nanocristal, Nanocrystal, Nanomatériau, Nanostructured materials, 8107B, 8460J, 8560J, and NiO

We demonstrate a facile and general strategy based on ligand protection for the synthesis of unstable colloidal nanocrystals by using the synthesis of pure p-type NiO nanocrystals as an example. We find that the introduction of lithium stearate, which is stable in the reaction system and capable of binding to the surface of NiO oxide nanocrystals, can effectively suppress the reactivity of NiO nanocrystals and thus prevent their in situ reduction into NL The resulting p-type NiO nanocrystals, a highly demanded hole-transporting and electron-blocking material, are applied to the fabrication of organic solar cells and polymer light-emitting diodes, demonstrating their great potential as an interfacial layer for low-cost and large-area, solution-processed optoelectronic devices.