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Université de Fribourg

Misfit layer compounds: a platform for heavily doped 2D transition metal dichalcogenides

Leriche, Raphaël T. ; Palacio‐Morales, Alexandra ; Campetella, Marco ; Tresca, Cesare ; Sasaki, Shunsuke ; Brun, Christophe ; Debontridder, François ; David, Pascal ; Arfaoui, Imad ; Šofranko, Ondrej ; Samuely, Tomas ; Kremer, Geoffroy ; Monney, Claude ; Jaouen, Thomas ; Cario, Laurent ; Calandra, Matteo ; Cren, Tristan

In: Advanced Functional Materials, 2020, p. 2007706

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double‐layer field‐effect transistors (FET). However, for the case of single layer NbSe2, FET doping is limited to ≈1 × 1014 cm−2, while a somewhat larger...

Université de Fribourg

Structural phase transition and bandgap control through mechanical deformation in layered semiconductors 1T–ZrX2 (X = S, Se)

Martino, Edoardo ; Santos-Cottin, David ; Le Mardelé, Florian ; Semeniuk, Konstantin ; Pizzochero, Michele ; Čerņevičs, Kristia̅ns ; Baptiste, Benoît ; Delbes, Ludovic ; Klotz, Stefan ; Capitani, Francesco ; Berger, Helmuth ; Yazyev, Oleg V. ; Akrap, Ana

In: ACS Materials Letters, 2020, vol. 2, no. 9, p. 1115–1120

Applying elastic deformation can tune a material’s physical properties locally and reversibly. Spatially modulated lattice deformation can create a bandgap gradient, favoring photogenerated charge separation and collection in optoelectronic devices. These advantages are hindered by the maximum elastic strain that a material can withstand before breaking. Nanomaterials derived by exfoliating...

Université de Neuchâtel

Ecosystem engineers’ contribution to soil structure formation in floodplains

Schomburg, Andreas ; Le Bayon, Claire (Dir.) ; Guenat, Claire (Codir.) ; Brunner, Philip (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Soil structure formation constitutes an extremely important process in near-natural and restored floodplains. A stable soil structure protects riverbanks from erosion and contributes to the preservation of ecosystem services. However, developing a soil structure in alluvial soils is difficult for several reasons. Extensive alluvial dynamics cause periodic waterlogging and continuously rejuvenate...

Université de Fribourg

Excitonic channels from bio-inspired templated supramolecular assembly of J-aggregate nanowires

Anantharaman, Surendra B. ; Messmer, Daniel ; Sadeghpour, Amin ; Salentinig, Stefan ; Nüescha, Frank ; Heier, Jakob

In: Nanoscale, 2019, vol. 11, no. 14, p. 6929–6938

Supramolecular assemblies with controlled morphology are of paramount importance for energy transport in organic semiconductors. Despite considerable freedom in molecular design, the preparation of dyes that form one dimensional J-aggregates is challenging. Here, we demonstrate a simple and effective route to functionalize dendronized polymers (DPs) with J-aggregates to construct tubular...

Université de Fribourg

Linear behavior of the optical conductivity and incoherent charge transport in ${\mathrm{BaCoS}}_{2}$

Santos-Cottin, D. ; Klein, Y. ; Werner, Philipp ; Miyake, Takashi ; Medici, L. de ; Gauzzi, A. ; Lobo, R. P. S. M. ; Casula, Michele

In: Physical Review Materials, 2018, vol. 2, no. 10, p. 105001

Optical conductivity measurements on a BaCoS2 single crystal unveil an unusual linear behavior over a broad spectral range. In the paramagnetic phase above 300 K, the spectrum shows no gap, which contradicts the previously proposed scenario of a charge-transfer Mott insulator. Ab initio dynamical mean field theory calculations including a retarded Hubbard interaction explain the data in terms...

Université de Fribourg

Mimicking the chemistry of natural eumelanin synthesis: the ke sequence in polypeptides and in proteins allows for a specific control of nanosized functional polydopamine formation

Bergtold, Camille ; Hauser, Daniel ; Alain Chaumont ; El Yakhlifi, Salima ; Mateescu, Mihaela ; Meyer, Florent ; Metz-Boutigue, Marie-Hélène ; Benoît Frisch ; Schaaf, Pierre ; Ihiawakrim, Dris ; Ersen, Ovidiu ; Monnier, Christophe A. ; Petri-Fink, Alke ; Rothen-Rutishauser, Barbara ; Ball, Vincent

In: Biomacromolecules, 2018, vol. 19, no. 9, p. 3693–3704

The oxidation of dopamine and of other catecholamines leads to the formation of conformal films on the surface of all known materials and to the formation of a precipitate in solution. In some cases, it has been shown that the addition of additives in the dopamine solution, like certain surfactants or polymers, polyelectrolytes, and certain proteins, allows to get polydopamine nanoparticles...

Haute Ecole Arc Conservation-Restauration

Etude et conservation-restauration d'un cabinet chinois d'export en laque polychrome, XIXe siècle. Musée Ariana

Pedersen, Line

Mémoire de master : Haute Ecole Arc Conservation-Restauration, 2018.

Diese Masterarbeit besteht aus der historischen und technologischen Studie und der konservatorischen Restaurierung eines polychromen Holz- und Lack-Kabinetts aus China, das im 19. Jahrhundert für den Export hergestellt wurde. Es ist derzeit im Ariana Museum in Genf erhalten. Das Hauptziel bestand darin, durch eine Reinigung der schmutzigen Oberflächen und eine Stabilisierung der Auskleidung das...

Université de Fribourg

Novel iron tweezers complexes for hydrogenation and polymerization of olefins

Mafua, Roger ; Jenny, Titus A. (Dir.)

Thèse de doctorat : Université de Fribourg, 2006 ; no. 1503.

The use of organometallic complexes as catalysts became a very significant topic in the field of material chemistry. However, despite of this development, only few of them contain iron(II), except the tridentate complex diimine pyridine developed by Gibson and Brookhart and employed in the olefin polymerization. Unfortunately, this model suffers by its lack of tolerance towards the minor changes...