Local Electronic Structure and Density of Edge and Facet Atoms at Rh Nanoclusters Self-Assembled on a Graphene Template

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While gas aggregation cluster sources can tailor the chemistry, size, and shape of nanoparticles (NPs), low NP yield and instability over time still limit the fabrication of nanoparticle-based coatings or nanocomposite films. In this work, we propose controlled addition of ambient air as a nucleation source to enhance the efficiency and stability of the process. Additionally, the type of power source is varied, juxtaposing direct current and high-power impulse magnetron sputtering. Quadruple mass spectromet

Solid oxide cells (SOCs) are highly efficient electrochemical devices, yet their high‐temperature operation induces structural instabilities that limit long‐term performance. Thin‐film electrodes provide a model platform to probe such effects due to their well‐defined geometry and chemistry. Here, we combine high‐resolution electron microscopy, synchrotron X‐ray spectroscopy, and density functional theory to investigate the thermal stability of epitaxial lanthanum–strontium manganite (LSM) films on yttria‐s

Molecularly engineered interlayers have emerged as a powerful strategy to enhance the efficiency and stability of perovskite solar cells. [1] These interfacial layers bridge structural and electronic mismatches between the perovskite and charge transport layers (CTLs), yet the underlying mechanisms of charge transport across such interfaces remain poorly understood. In particular, it is unclear whether photogenerated electrons and holes cross the interface via tunneling or hopping mechanisms. Tunneling occu

Zn3P2, made from earth-abundant elements, is a promising candidate for thin-film solar cells but faces limitations due to difficulties in achieving n-type doping and its large lattice mismatch with commercial substrates and a high thermal expansion coefficient, causing defects and cracks. Graphene substrates can address these challenges thanks to its weak van der Waals interactions with Zn3P2 allowing for mechanical transfer of the thin film and strain-free growth. This study compares five graphene substrat

Carbon membranes yielding high selectivity as well as high permeance are attractive to advance the membrane-based gas separation. Herein, we report ultrathin carbon membranes (UCMs) which deliver enhanced gas separation performance through oxygen-modulated pyrolysis of poly(4-vinylpyridine) precursor. We show that O 2 in pyrolysis environment, transforms the otherwise uniform carbon network featuring a ~ 3.9 Å characteristic interlayer spacing into disrupted UCMs (d-UCMs). These d-UCMs possess a multimodal

Amorphous formulations are increasingly used in the pharmaceutical industry due to their increased solubility, but their structural characterization at atomic-level resolution remains extremely challenging. Here, we characterize the complete atomic-level structure of an amorphous glucagon-like peptide-1 receptor (GLP-1R) agonist using chemical shift driven NMR crystallography. The structure is determined from measured chemical shift distributions for 17 of the 32 carbon atoms and 16 of the 31 hydrogen atoms

Spatial and temporal light modulation is a well-established technology that enables dynamic shaping of the phase and amplitude of optical fields, significantly enhancing the resolution and sensitivity of imaging methods. Translating this capability to electron beams is highly desirable within the framework of a transmission electron microscope (TEM) to benefit from the nanometer spatial resolution of this instrument. In this work, we report on the experimental realization of a photonic-based free-electron m

The conduction band offset ϕ0 at semiconductor surfaces and interfaces is a crucial parameter for quantum devices exploiting proximity‐induced collective states such as superconductivity and magnetism. Recently, a method combining angle‐resolved conduction band and core‐level photoelectron spectroscopy was shown to yield band offsets aligning well with direct measurements of quantized conduction subband energies. However, the method was limited to surfaces with native accumulation layers. To address this sh

Electrons and phonons constitute the most fundamental degrees of freedom in the material world, underpinning the technological applications that have shaped everyday life. This thesis explores the emerging electron and phonon physics in novel materials, demonstrating the failure of many conventional treatments and common approximations. The first part develops the theoretical toolbox for modelling microscopic electron and phonon interactions as well as their transport. Specifically, we introduce a robust an

Some diseases are characterized at the biomolecular level by a change in the mechanical properties of the cells in comparison to normal cells. Detecting this change could thus be useful for biomedical pplications. Micromechanical sensors are devices that are already used to study different phenomena at the micro-scale. The measurement of the eflection or the resonance frequency shift of a beam in response to an added mass for example enables to characterize samples obtaining information such as the size, th

We have investigated the electronic response of single crystals of indium selenide by means of angle-resolved photoemission spectroscopy, electron energy loss spectroscopy and density functional theory. The loss spectrum of indium selenide shows the direct ...

Valorization of lignocellulosic biomass for the production of commodity chemicals using various chemical methods continues to attract considerable attention. A wide and diverse range of different chemicals can be obtained from biomass and many different downstream pathways are currently under development. The conversion of various cellulosic derivatives such as glucose and fructose to 5-hydroxymethylfurfural (HMF) has been identified as a key route. However, since HMF is intrinsically unstable, its transfor

Molecular self-assembly at metal surfaces has been recognized as an efficient strategy to create supramolecular nanoarchitectures with promising functionalities. The focus of this thesis lies on the strong electron accepting molecule 7,7,8,8-tetracyanoquin ...

This thesis presents an investigation of the models describing electrical conductivity in polymer nanocomposites, which consist in more or less random dispersions of nanometric conductive fillers like carbon nanotubes, nanofibers or graphene sheets in a po ...

The occurrence of an ultrathin SiO2 oxide layer at the interface between silicon and high-k dielectrics in metal-oxide-semiconductor devices contributes to degrading the capacitance of the gate stack. In this work, we investigate the dielectric and infrared properties of atomically thin SiO2 layers on Si(100) through a fully quantum-mechanical description. For this purpose, we construct atomistic models of the Si(100)-SiO2 interface on the basis of available experimental data, by using both classical and fi

Non volatile flash memories based on nanoparticles are one of the possible routes to further downscaling of CMOS technology. The increase of scale integration should involve some new features for memory cells such as Coulomb blockade and quantized charging effects. These previously mentioned effects appear at room temperature, for nanometer sized nanoparticles (nps), if their number is reduced to a few or even a single particle. Fabrication of 2D arrays of Si nanoparticles have been previously demonstrated

The development of nanodevices demands for patterning methods in the nanoscale. To bring nanodevices to the market, there is a need for fast, low-cost nanopatterning methods. In addition, an increased flexibility is important for the engineering of multimaterial and multifunctional nano/micro-electro-mechanical systems (NEMS/MEMS), such as polymer-based electronic and sensor devices, 3D microfluidic systems, and bio-analytical systems. A series of alternative surface micro/nanopatterning methods based on ME

Conventional Hall devices are widely employed to measure magnetic fields produced by millimetre sized (or larger) current-caring conductors or permanent magnets with a standard active area of about (100 um)^2. Micro-Hall sensors have recently emerged as a powerful and sensitive tool for the investigation of local magnetic field properties of the micro and nano-structures. The conventional Hall effect devices are based on non-magnetic materials (typically semiconductors e.g: AlGaAs/GaAs and InSb or semimetal

We have studied systems of asymmetric coupled GaAs V-groove quantum wires, in which the electrons and holes are injected into different wires. Our experimental results indicate efficient electron and hole tunneling, despite a 7 nm thick AlGaAs tunnel barrier. Temperature dependent electroluminescence exhibit clear effects of tunneling up to room temperature but cannot distinguish electron/hole tunneling from exciton tunneling.

One of the intrinsic difficulties for in situ photoemission studies of high T-c oxide films is the surface volatility, especially the oxygen loss. In order to solve this problem, we have constructed a dedicated system for high T-c film surface studies, in particular for ARPES measurements. Here we briefly describe our pulsed laser deposition (PLD) system that is linked to the photoemission chamber at the Synchrotron Radiation Center (SRC) in Wisconsin, and discuss crystallographic and electronic properties

Local Electronic Structure and Density of Edge and Facet Atoms at Rh Nanoclusters Self-Assembled on a Graphene Template

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Morphology and yield of W nanoparticles in gas aggregation: Pathways towards functional nanocomposite films

Interfacial Atomic and Electronic Structures of LSM/YSZ Thin Films as Models for SOC Air Electrodes

Hopping or Tunneling? Charge Transport Across Molecularly Engineered Perovskite Interfaces

Link between graphene features and the resulting functionality of quasi-van der Waals Zn3P2

Oxygen-induced multimodal ultramicroporous structure in 10-nm-thick carbon membranes for enhanced hydrogen separation

The three-dimensional atomic-level structure of an amorphous glucagon-like peptide-1 receptor agonist

Realization of a Pre-Sample Photonic-Based Free-Electron Modulator in Ultrafast Transmission Electron Microscopes

Band Offsets from Angle‐Resolved Valence Band Photoemission Spectroscopy

Thermodynamics and Exotic Transport Phenomena in Emerging Materials

Fabrication of suspended microchannel resonators for biosensing application

Indium selenide: an insight into electronic band structure and surface excitations

Rational development of an electron-rich platinum nanocatalyst for the oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxilic acid under mild conditions

TCNQ-based Supramolecular Architectures at Metal Surfaces

On the insulator-conductor transition in polymer nanocomposites

Dielectric and infrared properties of ultrathin SiO2 layers on Si(100)

Synthesis of localized 2D-layers of silicon nanoparticles embedded in a SiO2 layer by a stencil-masked ultra-low energy ion implantation process

Emerging nanopatterning methods based on MEMS tools

Bismuth Micro and Nano Hall Sensors on Photo-plastic Cantilevers for Scanning Hall Probe Microscopy

Electrolummescence of asymmetric coupled GaAs/AlGaAs V-groove quantum wires

Surface optimization of RBa2Cu3O7-delta (R = Y, Nd) epitaxial high T-c films for in situ photoemission studies