Publications de Alexander Wokaun

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

Paul Bowen, Andrea Testino, Mohammad Reza Andalibi, Alexander Wokaun

An overarching computational framework unifying several optical theories to describe the temporal evolution of gold nanoparticles (GNPs) during a seeded growth process is presented. To achieve this, we used the inexpensive and widely available optical exti ...

2019

Determination of Conduction and Valence Band Electronic Structure of LaTiOxNy Thin Film

Nicola Marzari, Ivano Eligio Castelli, Alexander Wokaun

The nitrogen substitution into the oxygen sites of several oxide materials leads to a reduction of the band gap to the visible-light energy range, which makes these oxynitride semiconductors potential photocatalysts for efficient solar water splitting. Oxy ...

Wiley-V C H Verlag Gmbh2017

Enhanced Proton Conductivity in Y-Doped BaZrO3 via Strain Engineering

Nicola Marzari, Aris Marcolongo, Alexander Wokaun

The effects of stress-induced lattice distortions (strain) on the conductivity of Y-doped BaZrO3, a high-temperature proton conductor with key technological applications for sustainable electrochemical energy conversion, are studied. Highly ordered epitaxi ...

2017

Highly sensitive SnO2 sensor via reactive laser-induced transfer

Ulrike Lehmann, Alain Grisel, Alexander Wokaun

Gas sensors based on tin oxide (SnO2) and palladium doped SnO2 (Pd:SnO2) active materials are fabricated by a laser printing method, i.e. reactive laser-induced forward transfer (rLIFT). Thin films from tin based metal-complex precursors are prepared by sp ...

Nature Research2016

The optimisation of the laser-induced forward transfer process for fabrication of polyfluorene-based organic light-emitting diode pixels

Alexander Wokaun

Laser-induced forward transfer (LIFT) has already been used to fabricate various types of organic light-emitting diodes (OLEDs), and the process itself has been optimised and refined considerably since OLED pixels were first demonstrated. In particular, a ...

Elsevier Science Bv2013

Electrochemical Stability of Imidazolium Based Ionic Liquids Containing Cyano Groups in the Anion: A Cyclic Voltammetry, XPS and DFT Study

Paul Joseph Dyson, Zhaofu Fei, Alexander Wokaun

The electrochemical stability of ionic liquids based on the 1-ethyl-3-methyl imidazolium EMIM cation and three different anions, dicyanoamide (N(CN)(2)), tricyanomethanide (C(CN)(3)) and tetracyanoborate (B(CN)(4)), has been investigate ...

Electrochemical Society2012

Sequential Printing by Laser-Induced Forward Transfer To Fabricate a Polymer Light-Emitting Diode Pixel

Alexander Wokaun

Patterned deposition of polymer light-emitting diode (PLED) pixels is a challenge for electronic display applications. PLEDs have additional problems requiring solvent orthogonality of different materials in adjacent layers. We present the fabrication of a ...

2012

Studying the Formation of Ni3C from CO and Metallic Ni at T=265 degrees C in Situ Using Ni K-Edge X-ray Absorption Spectroscopy

Christian Ludwig, Rudolf Paul Wilhelm Jozef Struis, Alexander Wokaun

Metallic Ni nanopowder (Ni-0) was monitored during 23 h of carburization (2CO + 3Ni(0) - Ni3C + CO2, T = 265 degrees C) using Ni K-edge X-ray absorption spectroscopy. X-ray diffraction analysis made afterward at room temperature revealed 28 +/- 3% Ni3C amo ...

American Chemical Society2009

Qualitative evaluation of alkali release during the pyrolysis of biomass

Christian Ludwig, Alexander Wokaun

The thermochemical emission of alkali metals from biomass samples and two organic salts was investigated for the first time using a novel combination of a th ermogravi metric analyzer with a jet flow condenser attached to a surface ionization detector. Thi ...

2007