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Prague, Czech Republic

Lipton-Duffin J.A.,Center for Energy | Macleod J.M.,Center for Energy | Vondracek M.,Fyzikalni Ustav AV CR | Prince K.C.,Elettra - Sincrotrone Trieste | And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2014

We have performed a high-resolution synchrotron radiation photoelectron spectroscopy study of the initial growth stages of the ZnPd near-surface alloy on Pd(111), complemented by scanning tunnelling microscopy data. We show that the chemical environment for surfaces containing less than half of one monolayer of Zn is chemically distinct from subsequent layers. Surfaces where the deposition is performed at room temperature contain ZnPd islands surrounded by a substrate with dilute Zn substitutions. Annealing these surfaces drives the Zn towards the substrate top-layer, and favours the completion of the first 1:1 monolayer before the onset of growth in the next layer. © 2014 the Owner Societies. Source

Starman S.,Starmans electronics | Matz V.,Starmans electronics | Kvaca Z.,Molecular cybernetics | Mohyla M.,Molecular cybernetics | And 4 more authors.
NANOCON 2011 - Conference Proceedings, 3rd International Conference | Year: 2011

Based on the known Aurivillius phases types ABi2Ta2O9 and A2BiTaO6 (A=Ca,Sr,Ba) ) were supplemented with new compositions of layered tantalates, which resulted the possibility of the existence of a new phase Sr2BiTaO6. Ternary compounds with piezoelectric structure were prepared as nanoforms by solgel reactions of homogeneous acetate Bi, Ta, A and subsequent annealing in a controlled atmosphere. Annealing temperature was determined from DSC curves based on the weight loss and phase transitions. Composition and structure of nanocrystals has been analyzed by X-ray diffraction (XRD), scanning nanomorphology (SEM) and acoustic measurements. © 2011 TANGER Ltd., Ostrava. Source

Necesal P.,Fyzikalni Ustav AV CR
Journal of Physics: Conference Series | Year: 2011

The Pierre Auger Observatory is a facility designed for the study of ultra-high energy cosmic rays. The Observatory combines two different types of detectors: a surface array of 1600 water Cherenkov stations placed on a 1.5 km triangular grid covering over 3000 km2; and a fluorescence detector of 24 telescopes located in 4 buildings at the perimeter of the surface array. The fluorescence telescopes, each consisting of 440 photomultipliers, collect the ultraviolet light produced when the charged secondary particles in an air shower excite nitrogen molecules in the atmosphere. Because the intensity of the nitrogen fluorescence is proportional to the energy deposited in the atmosphere during the air shower, the air fluorescence measurements can be used to make a calorimetric measurement of the cosmic ray primary energy. Showers observed independently by the surface array and fluorescence telescopes, called hybrid events, are critical to the function of the Observatory, as they allow for a model-independent calibration of the surface detector. In this paper I describe the detector and the most important measurements. Source

Cardenas L.,University of Quebec | Cardenas L.,McGill University | Gutzler R.,University of Quebec | Gutzler R.,McGill University | And 10 more authors.
Chemical Science | Year: 2013

We report the synthesis and first electronic characterization of an atomically thin two dimensional π-conjugated polymer. Polymerization via Ullmann coupling of a tetrabrominated tetrathienoanthracene on Ag(111) in ultra-high vacuum (UHV) produces a porous 2D polymer network that has been characterized by scanning tunnelling microscopy (STM). High-resolution X-ray photoelectron spectroscopy (HRXPS) shows that the reaction proceeds via two distinct steps: dehalogenation of the brominated precursor, which begins at room temperature (RT), and C-C coupling of the resulting Ag-bound intermediates, which requires annealing at 300 °C. The formation of the 2D conjugated network is accompanied by a shift of the occupied molecular states by 0.6 eV towards the Fermi level, as observed by UV photoelectron spectroscopy (UPS). A theoretical analysis of the electronic gap reduction in the transition from monomeric building blocks to various 1D and 2D oligomers and polymers yields important insight into the effect of topology on the electronic structure of 2D conjugated polymers. © 2013 The Royal Society of Chemistry. Source

Fyzikalni Ustav Av Cr and Oerlikon Solar Ltd. | Date: 2010-09-16

A photovoltaic cell (

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