Publications de Ulrich Aschauer

Self-Assembly of N-Rich Triimidazoles on Ag(111): Mixing the Pleasures and Pains of Epitaxy and Strain

Ulrich Aschauer, Christian Wäckerlin, Xing Wang, Mehdi Heydari

In the present report, homochiral hydrogen-bonded assemblies of heavily N-doped (C9H6N6) heterocyclic triimidazole (TT) molecules on an Ag(111) substrate were investigated using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) ...

Amer Chemical Soc2023

Interactions of Tris with rutile surfaces and consequences for in vitro bioactivity testing

Paul Bowen, Ulrich Aschauer

Tris(hydroxymethyl)aminomethane (Tris) has been used as the buffer in bioactivity testing for over two decades and has become a standard choice for the scientific community. While it is believed to be non-interacting, the extent of its interactions with ti ...

Elsevier2021

Synthesis and Size-Dependent Optical Properties of Intermediate Band Gap Cu3VS4 Nanocrystals

Ulrich Aschauer, Seryio Saris, Raffaella Buonsanti, Anna Loiudice, Valeria Mantella

Intermediate band gap semiconductors are an underex-plored class of materials with unique optical properties of interest for photovoltaic and optoelectronic applications. Herein, we synthesize highly crystalline cubic Cu3VS4 nanocrystals with tunable edge ...

2019

Self-consistent site-dependent DFT plus U study of stoichiometric and defective SrMnO3

Ulrich Aschauer, Nicola Marzari, Matteo Cococcioni, Iurii Timrov

We propose a self-consistent site-dependent Hubbard U approach for density functional theory (DFT)+U calculations of defects in complex transition metal oxides, using Hubbard parameters computed via linear response theory. The formation of a defect locally ...

AMER PHYSICAL SOC2019

Determination and optimization of material parameters of particle-based LaTiO2N photoelectrodes

Ulrich Aschauer, Yannick Kenneth Gaudy, Sophia Haussener

We developed a validated numerical model capable of predicting the photocurrent-voltage characteristics of oxide and oxynitride particle-based photoelectrodes and identifying the critical parameters affecting the performance of those photoelectrodes. We us ...

Royal Society of Chemistry2018

Interaction of biologically relevant ions and organic molecules with titanium oxide (rutile) surfaces: A review on molecular dynamics studies

Paul Bowen, Ulrich Aschauer, Azade Yazdan Yar

The surface of a biomaterial can play a major role in its biological fate since the surface is the primary pathway for its interaction with the body. As the natural response of the body to a foreign material is to encapsulate it with a fibrous material, th ...

2018

Adsorption Free Energy of Single Amino Acids at the Rutile (110)/ Water Interface Studied by Well-Tempered Metadynamics

Paul Bowen, Ulrich Aschauer, Azade Yazdan Yar

Single amino acids are present in blood plasma and are the building blocks of larger organic residues. Their interaction with surfaces is therefore crucial for biomedical applications in contact with blood. In this work, we use well-tempered metadynamics t ...

2018

Versatility of Pyridoxal Phosphate as a Coating of Iron Oxide Nanoparticles

Heinrich Hofmann, Ulrich Aschauer, Marijana Mionic Ebersold, Débora Bonvin, Josefina Adriana Maria Bastiaansen

Pyridoxal 5'-phosphate (PLP) is the most important cofactor of vitamin B-6-dependent enzymes, which catalyses a wide range of essential body functions (e.g., metabolism) that could be exploited to specifically target highly metabolic cells, such as tumour ...

Mdpi Ag2017

Synthesis of Responsive Two-Dimensional Polymers via Self-Assembled DNA Networks

Ulrich Aschauer, Duncan Thomas Lindsay Alexander, Hao Yu

Despite a growing interest in two-dimensional polymers, their rational synthesis remains a challenge. The solution-phase synthesis of a two-dimensional polymer is reported. ADNA-based monomer self-assembles into a supra-molecular network, which is further ...

Wiley-VCH Verlag GmbH2017

Protein Corona: Impact of Lymph Versus Blood in a Complex In Vitro Environment

Heinrich Hofmann, Ulrich Aschauer, Marc Moniatte, Diego Chiappe, Marijana Mionic Ebersold, Duncan Thomas Lindsay Alexander, Débora Bonvin

In biological environments, the surface of nanoparticles (NPs) are modified by protein corona (PC) that determines their biological behavior. Unfortunately, in vitro tests still give different PC than in vivo tests causing in vitro-in vivo discrepancy; hen ...

Wiley-Blackwell2017

Atomistic Modeling of Effect of Mg on Oxygen Vacancy Diffusion in alpha-Alumina

Paul Bowen, Ulrich Aschauer, Abhishek Tewari

Oxygen diffusion plays an important role in grain growth and densification during the sintering of alumina ceramics and governs high-temperature processes such as creep. The atomistic mechanism for oxygen diffusion in alumina is, however, still debated; at ...

Wiley-Blackwell2014

Atomistic modeling of dopant segregation in alpha-alumina ceramics: Coverage dependent energy of segregation and nominal dopant solubility

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini, Yann Aman, Abhishek Tewari

Microstructural control is a key aspect in producing ceramics with tailored properties and is often achieved by using dopants in a rather empirical fashion. Atomic scale simulations could provide much needed insight but the long-standing challenge of linki ...

2011

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4 + δ: Fabrication and characterisation of dip-coated electrolyte layers

Paul Bowen, Heinrich Hofmann, Jan Van Herle, Ulrich Aschauer, Josef Andreas Schuler, Henning Lübbe

Fabrication conditions to obtain dense electrolyte double layers on a porous micro-tubular cathode substrate were investigated. Porous tubes of a nickelate material, Nd1.95NiO4 + δ, were fabricated by cold-isostatic pressing (CIP) and sintering. Thin ﬁlms ...

2009

Growth modification of hematite by phosphonate additives

Paul Bowen, Heinrich Hofmann, Ulrich Aschauer

The hydroxylated surface structures of seven morphologically important crystallographic surfaces of hematite were calculated allowing the determination of the surface energies and, consequently,the hematite equilibrium morphology. The docking of two organi ...

2008

Surface and Mirror Twin Grain Boundary Segregation in Nd:YAG: An Atomistic Simulation Study

Paul Bowen, Ulrich Aschauer

Ceramic lasers have advantages such as better optical homogeneity, cheaper production, and more freedom in shape compared with monocrystalline lasers. However, equal or better laser performances are required. Interface segregation is important as ceramics ...

2008

Atomistic Simulation of Y-Doped alpha-Alumina Interfaces

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini

The exact mechanism of creep resistance enhancement due to yttrium (Y) doping in a-alumina is still subject to speculation, although it is known that dopants segregate strongly to grain boundaries. The current work applies atomistic simulation techniques t ...

2008

Atomistic simulation in powder technology : from growth control and dispersion stabilization to segregation at doped interfaces

Ulrich Aschauer

Despite many years of intensive research there still remain many unresolved questions in powder and ceramic technology. A majority of these issues are linked to interfacial phenomena of atomic scale origin, which makes their experimental investigation very ...

EPFL2008

Atomistic Modeling Study of Surface Segregation in Nd:YAG

Paul Bowen, Ulrich Aschauer

This study investigates the composition of free surfaces of neodymium-doped yttrium–aluminum–garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 0.5 nm ̊of the surface, the enrichment fact ...

2006

Grain Growth in Doped Oxide Ceramics: From Nanosizes Powders and Atomistic Simulations to Tailored Interfaces

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini

Swansea Materials Research Centre2006