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Luxembourg, Luxembourg

The University of Luxembourg is the only university in Luxembourg, founded on 13 August 2003. Prior to that, there were several higher educational institutions such as the cour universitaire or the IST that offered one or two years of academic studies. Luxembourgish students had to go abroad in order to complete their studies at a university . The new university makes it possible for these students to complete their studies in their own country, as well as attract foreign academic interest to Luxembourg.The University is currently divided into three Campuses, namely:Campus Limpertsberg hosting the Faculty of Law, Economics and Finance and parts of the Faculty of Science, Technology and Communication as well as the central administration units of the UniversityCampus Kirchberg hosting further parts of the Faculty of Science, Technology and CommunicationsCampus Walferdange hosting the Faculty of Language and Literature, Humanities, Arts and EducationBy the finalisation of the restructured campus in Esch-Belval, south of the capital, two of the three faculties will relocate there: The Faculty of Arts, Humanities, Arts and Education science will first do so in summer 2014, followed by the Faculty of science, Technology and Communication in 2015 and 2016. The Faculty of Law, Economics and Finance will remain on Campus Limpertsberg.Like Luxembourg itself, the studies at the University of Luxembourg are characterised by their multilingualism. Courses are usually held in two languages: French/English, French/German, or English/German. Wikipedia.

Siebentritt S.,University of Luxembourg | Schorr S.,Helmholtz Center Berlin
Progress in Photovoltaics: Research and Applications | Year: 2012

Kesterite materials (Cu 2ZnSn(S,Se) 4) are made from non-toxic, earth-abundant and low-cost raw materials. We summarise here the structural and electronic material data relevant for the solar cells. The equilibrium structure of both Cu 2ZnSnS 4 and Cu 2ZnSnSe 4 is the kesterite structure. However, the stannite structure has only a slightly lower binding energy. Because the band gap of the stannite is predicted to be about 100 meV lower than the kesterite band gap, any admixture of stannite will hurt the solar cells. The band gaps of Cu 2ZnSnS 4 and Cu 2ZnSnSe 4 are 1.5 and 1.0 eV, respectively. Hardly any experiments on defects are available. Theoretically, the Cu Zn antisite acceptor is predicted as the most probable defect. The existence region of the kesterite phase is smaller compared with that of chalcopyrites. This makes secondary phases a serious challenge in the development of solar cells. Copyright © 2012 John Wiley & Sons, Ltd.

Siebentritt S.,University of Luxembourg
Thin Solid Films | Year: 2013

Although kesterite solar cells show the same range of band gaps as the related chalcopyrites, their efficiencies have so far reached only 10%, compared with 20% for the chalcopyrites. A review of the present literature indicates that several non-ideal recombination channels pose the main problem: (i) recombination at the interface between the kesterite and the CdS buffer. This is very likely due to an unfavourable cliff-like band alignment between the absorber and the buffer. However, for pure selenide absorbers, this recombination path is not dominating, which could be due to a spike-like band alignment at the absorber-buffer interface. (ii) A second major recombination becomes obvious in a photoluminescence maximum well below the band gap, even in record efficiency absorbers. This is either due to a very high density of defects, comparable to the density of states in the band, or to stannite inclusions. In view of the phase diagram, secondary phases are not likely the source of the low energy emission. Only in sulphide kesterite a non-stoichiometric SnS phase could also cause this low energy radiative recombination. © 2013 Elsevier B.V.

Hesse M.,University of Luxembourg
Journal of Transport Geography | Year: 2013

This paper emphasizes the relationship between cities and (transport) flows and critically explores the question of how this relationship has changed over time.It ties in with the legacy of Brian Hoyle's work on port cities and discusses the general mechanisms and trajectories of urban development in the context of transport networks, particularly the tension between the concentration and dispersal of flows and their impact on places. Thus, the relationship between places and flows is considered both fundamental and delicate: that is, it is not only immanent to both, it also causes tensions and conflict. This is discussed in more detail in relation to two distinct cases: ports and airports. In response to related conflicts, the integration of flows in urban areas is pursued as a policy and planning strategy. However, the cases reveal that integration is difficult to achieve, due to complex systems' dynamics and the individual logic of each sector, where integration is often accompanied by disintegration. Some light is also shed on a constructivist view of the subject matter. Finally, some ramifications for research and planning practices will be presented. © 2013 Elsevier Ltd.

Horowitz J.M.,University of Massachusetts Boston | Esposito M.,University of Luxembourg
Physical Review X | Year: 2014

We provide a unified thermodynamic formalism describing information transfers in autonomous as well as nonautonomous systems described by stochastic thermodynamics. We demonstrate how information is continuously generated in an auxiliary system and then transferred to a relevant system that can utilize it to fuel otherwise impossible processes. Indeed, while the joint system satisfies the second law, the entropy balance for the relevant system is modified by an information term related to the mutual information rate between the two systems. We show that many important results previously derived for nonautonomous Maxwell demons can be recovered from our formalism and use a cycle decomposition to analyze the continuous information flow in autonomous systems operating at a steady state. A model system is used to illustrate our findings.

Siebentritt S.,University of Luxembourg
Solar Energy Materials and Solar Cells | Year: 2011

The limiting factors on the efficiency of current record devices are discussed. Optical and collection losses are found to have a minor influence. They reduce the short circuit current. Higher losses are due to recombination losses. The defects responsible for Shockley-Read-Hall recombination are discussed, and it is concluded that Shockley-Read-Hall recombination is not likely the source for the open circuit voltage loss. However the recombination is increased by inhomogeneities. Inhomogeneities of the band gap can be excluded, because they are too small to have significant influence. Electrostatic potential variations at charged extended defects like grain boundaries are however responsible for losses in the open circuit voltage. © 2010 Elsevier B.V. All rights reserved.

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