Étude cristallochimique de semi-conducteurs CIGSe pour cellules photovoltaïques en couches minces

L objectif de cette thèse était d étudier la cristallographie de composés sous forme de poudre ayant des propriétés photovoltaïques, les CIGSe (CuIn1 xGaxSe2). Ceux ci sont utilisés comme couche absorbante dans des cellules photovoltaïque en couche mince de seconde génération et commencent à être commercialisés, notamment aux USA et en Allemagne. Une ré investigation complète des composés poudre a ainsi été conduite par diffraction des rayons X sur poudre et monocristal, dans le but d améliorer la compréhension des phases cristallines, notamment pour des taux de cuivre très faibles. Des calculs de structure électronique ont été entrepris sur des compositions particulières de CIGSe afin de mieux comprendre certaines propriétés. Le composé historique CuInSe2 a ainsi servi de modèle théorique car possédant de nombreuses références expérimentales dans la littérature. Enfin, des échantillons en couches minces de CIGSe ont été préparées pour une étude par microscopie électronique à transmission. Le but était de voir l évolution de la qualité cristalline pour des forts taux de gallium, taux où les rendements des couches minces sont plus faiblesThis study mainly focuses on the crystallographic research of powder compounds with photovoltaic properties. They are used in photovoltaic thin film solar cell (2nd generation) as absorber layer. They have been produced and sold in the US and Germany in particular. A complete powder compounds re-investigation have been made by X-Ray diffraction on powder and single crystal. The aim of this research was to have a better comprehension of the crystalline phases, especially for copper poor compounds. Electronic structure calculation have been conducted on specific CIGSe composition to try to understand some special properties. The original compound CuInSe2 was used as theoretical model because many experimental references can be found in the literature. Finally, CIGSe thin-film sample have been prepared for a study by transmission electronic microscopy. The purpose was to check the crystal quality with high gallium content, because the efficiency of the solar cells tends to drop down as the gallium content increasingNANTES-BU Sciences (441092104) / SudocSudocFranceF

X-ray diffraction, Mössbauer spectrometry and thermal studies of the mechanically alloyed (Fe 1−x Mn x ) 2 P powders

International audienc

Microstructural, Hyperfine, and Magnetic Properties of FeSiBCuNb Deposits

International audienc

SARS-CoV-2 Nsp3 unique domain SUD interacts with guanine quadruplexes and G4-ligands inhibit this interaction

International audienceThe multidomain non-structural protein 3 (Nsp3) is the largest protein encoded by coronavirus (CoV) genomes and several regions of this protein are essential for viral replication. Of note, SARS-CoV Nsp3 contains a SARS-Unique Domain (SUD), which can bind Guanine-rich non-canonical nucleic acid structures called G-quadruplexes (G4) and is essential for SARS-CoV replication. We show herein that the SARS-CoV-2 Nsp3 protein also contains a SUD domain that interacts with G4s. Indeed, interactions between SUD proteins and both DNA and RNA G4s were evidenced by G4 pull-down, Surface Plasmon Resonance and Homogenous Time Resolved Fluorescence. These interactions can be disrupted by mutations that prevent oligonucleotides from folding into G4 structures and, interestingly, by molecules known as specific ligands of these G4s. Structural models for these interactions are proposed and reveal significant differences with the crystallographic and modeled 3D structures of the SARS-CoV SUD-NM/G4 interaction. Altogether, our results pave the way for further studies on the role of SUD/G4 interactions during SARS-CoV-2 replication and the use of inhibitors of these interactions as potential antiviral compounds