<p>Cryogenic transmission electron microscopy (cryoEM) has become an increasingly common tool for determining structures of proteins and protein complex at near atomic resolution. We seek to determine the structure of p97 by cryoEM using an affinity capture approach that employs a family of novel synthetic lipids bearing water soluble PEG units and known high affinity inhibitor molecules at the distal end of the polymer. A library of inhibitor modified affinity lipopolymers of 5000 KD PEG molecular weights were synthesized. The inhibitor modified lipid coated grids were used to capture p97. The reconstruction of p97 revealed the structure at dimeric state at 3.64 Å and monomeric state at 4.33 Å. A PEG unit composed of 20000 KD molecular weight based polyrotaxane containing NTA ligand as affinity tag has been synthesized, used to concentrate 6x-his tagged p97 on TEM which also enabled to see all 3D orientation of the target particles and an initial model of 10.64 Å resolution of p97 structure was resolved. </p>

Organic photovoltaics (OPVs) have received tremendous attention in recent years due to their numerous attractive attributes such as, the potential for high power conversion efficiency (PCE), mechanical flexibility, and the potential for large-scale manufacturing via low-cost techniques. To date, the record PCE values for bulk-heterojunction (BHJ) OPVs exceed 18% for single-junction cells thanks to the rapid development of donors and acceptors materials for active layer. However, the progress of hole-transporting layer (HTL) systems, which is a key device component to reduce the additional performance losses of OPVs, has been limited with only a handful of materials available like PEDOT:PSS and MoOX. In this thesis, I introduce serval materials to unitize as hole-selective contact in high-performance OPVs. Firstly, the application of liquid-exfoliated two-dimensional transition metal disulfides (TMDs) is demonstrated as the HTLs in OPVs. The solution processing of few-layer WS2 suspensions was directly spun onto transparent indium-tin-oxide (ITO) electrodes yield solar cells with superior power conversion efficiency (PCE), improved fill-factor (FF), enhanced short-circuit current (JSC), and lower series resistance than devices based on PEDOT:PSS. Based on PM6:Y6:PC71BM BHJ layer, the cells with WS2 HTL exhibit the highest PCE of 17% thanks to the favorable photonic structure and reduced bimolecular recombination losses in WS2-based cells. Next, the self-assembled monolayer (SAM) namely 2PACz is utilized as hole-selective contact directly onto the ITO anode. The 2PACz modifies the work function of ITO while simultaneously affecting the BHJ layer’s morphology deposited atop. This ITO-2PACz anode is utilized in OPV with PM6:BTP-eC9:PC71BM, showing a remarkable PCE of 18.0%. The enhanced performance is attributed to reduced contact-resistance, lower bimolecular recombination losses, and improved charge transport within the BHJ layer. Lastly, the previously 2PACz SAM was functionalized with bromide functional groups, namely Br-2PACz, which is investigated as hole-extracting interlayers in OPVs. The highest occupied molecular orbital (HOMO) energy of Br-2PACz was measured at -6.01 eV, and significant changes the work function of ITO electrodes upon chemical functionalization. OPV cells based on PM6:BTP-eC9:PC71BM using ITO/Br-2PACz anodes exhibit a maximum PCE of 18.4%, outperforming devices with ITO/PEDOT:PSS (17.5%), resulting from lower interface resistance, improved hole transport, and longer carrier lifetimes.

Amino acid phenylalanine plays a key role in numerous biological processes and is also involved in amyloid fibril diseases. The aim of the thesis is to deepen our understanding of its behavior and partitioning at interfaces, and to investigate its clustering. Classical atomistic molecular dynamics simulations were performed for phenylalanine and three other aromatic molecules which chemical structure is derived from it - phenylglycine, phenylacetic acid and tyrosine. Molecules are simulated at both water-air and at water-DPPC-air interfaces. Phenylalanine, phenylglycine and phenylacetic acid demonstrate surface activity at the water-air interface, whereas tyrosine is not surface active. All molecules interact with the lipid monolayer at the water-DPPC-air interface but only phenylalanine penetrates deep into the monolayer. Formation of transient clusters is observed in the interfacial regions, mostly for phenylalanine. Powered by TCPDF (www.tcpdf.org)

The thesis examines the adhesive interaction between graphite layers and atomically thin MoS2 crystals. Vertical van der Waals(vdW) heterostructures are fabricated by stacking different two-dimensional (2D) materials on top of each other. Blister test is used to measure the adhesive interactions between 2D heterostructures and their transferred substrates and between the layers themselves. This adhesive interaction is important in maintaining the mechanical integrity of the device during mechanical loadings and its understanding will help pave the way to the design and fabrication of micromechanical device from 2D heterostructures. Furthermore, applying controlled strains can be used to alter the electrical and optical properties thereby improving efficiency and performance. At first, we grew MoS2 and graphene by CVD and stacked the layers on top of each other using a dry transfer method. The MoS2/graphene heterostructure was then transferred onto pre-etched cavities on a silicon wafer. The blister test was used for controllably introducing strain into the heterostructure. Atomic Force Microscopy was used for measuring the shape of the deformed blister and Raman and Photoluminescence(PL) measured the optical response. The strain mismatch between the biaxial strain and a PL-converted strain suggests crumpling of the graphene layer and a substantial softening of the mechanical response. Lastly, we created graphite holes with photolithography to measure the work of separation between an atomically smooth graphite surface and MoS2. We found this value to be at least 320mJ/m2 which is higher than the MoS2/SiOx areas that was previously studied. / 2023-07-02T00:00:00Z

1-D and 2-D organic nanostructures formed by supramolecular self-assembly on HOPG(0001)from molecules containing amide and carboxylic moieties have been investigated with scanning tunneling and force microscopy operated in ambient conditions. A Precise determination of the structure of the monolayer of arachidic acid on graphite was found from moire pattern resulting from tunneling current contributions from both the monolayer and the substrate. Wedge-shaped benzamide amphiphilic molecules deposited on HOPG mainly showed 1-D structures. Systematically varied molecular geometry and head groups reveal the architecture of nanowires which are distinctly different from their columnar mesophase in solution.

Dans ce travail, nous étudions les conditions de synthèse pour la croissance directe des MOF Fe3 + / H2BDC et Fe3 + / H2NDC sur des surfaces de silicium fonctionnalisées (111) présentant une structure bien définie et dont la chimie de surface peut être adaptée pour favoriser / diriger la nucléation et la croissance hétérogènes Des MOF. Le mécanisme de croissance des MOF pertinents aux conditions choisies et les propriétés flexibles des cadres MIL-88B et MIL-88C sont également présentés avec l'aide des résultats du traitement post-synthèse.En ce qui concerne le système de morphologies et structures Fe3 + / H2BDC, les structures des couches obtenues dépendent fortement de la chimie de surface des monocouches greffées et aussi des conditions de synthèse (température, composition de la solution et temps de réaction). Les cristaux MIL-88B orientés sur la direction [001] sont seulement observés sur des surfaces fonctionnalisées par COOH et se sont révélés être favorisés en présence d'un excès de ligand en solution. La formation de la phase MIL-101 texturée le long de la direction [111] sur les surfaces de Si pyridyl et hydroxy-terminé est observée indépendamment de la condition de synthèse. Des cristaux MIL-101 isolés avec une orientation préférée le long de la direction [111] ont également été trouvés sur une surface terminée par acide à un excès de métal, alors que les îlots MIL-101 orientés au hasard sont observés au rapport R ≧ 1. Au contraire, aucune croissance du film ne s'est produite sur les surfaces de Si à terminaison méthyle. L'introduction de HCl, de H2O et de base faible organique -triéthylamine dans les solutions précurseurs affecte également la formation de films MOF avec différentes morphologies et couverture entre MIL-101 et MIL-88B sur des surfaces de Si à terminaison carboxylique. La dépendance temporelle de la croissance du film à un excès de ligand (R = 2) et d'un excès de métal (R = 0,5) sans et avec addition de HCl indique clairement que les deux MIL-88B et MIL-101 suivent un mode de croissance Volmer-Weber, Au cours de laquelle, des cristaux ou des grappes tridimensionnels isolés se sont formés à l'étape initiale et se sont développés latéralement et verticalement à la surface.En ce qui concerne le système de Fe3 + / H2NDC, en fonction des conditions de synthèse, y compris la température, le rapport du ligand à la concentration [Fe3 +] et [Fe3 +] seulement une phase-MIL-88C avec une couverture de surface variable allant des cristaux hexagonaux séparés aux couches composées d'isolés On a observé des faisceaux de cristallites hexagonales tous avec une orientation préférentielle le long de la direction. L'évolution des cristaux de MIL-88C avec le temps de cristallisation suggère également un mode Volmer-Weber.Les mesures ex-situ XRD du post-traitement vers les couches synthétisées constituées de MIL-88B et MIL-88C démontrent respectivement leur flexibilité lors de la désorption des molécules. Les mesures provisoires de la XRD in situ montrent également la réversibilité du cadre MIL-88C lors de l'absorption et de la libération de l'éthanol. / Within this work we investigate synthesis conditions for the direct growth of Fe3+/H2BDC and Fe3+/H2NDC MOFs onto functionalized silicon (111) surfaces exhibiting well-defined structure and whose surface chemistry can be tailored in order to favor/direct the heterogeneous nucleation and growth of the MOFs. Growth mechanism of relevant MOFs at chosen conditions and flexible properties of MIL-88B and MIL-88C frameworks are presented as well with the assistance of post-synthesis treatment results.Regarding the system of Fe3+/H2BDC morphologies and structures of obtained layers strongly depend both on surface chemistry of grafted monolayers and also on the synthesis conditions (temperature, solution composition and reaction time). Oriented MIL-88B crystals along [001] direction is only observed onto COOH-functionalized surfaces and was found to be favored in presence of ligand excess in solution. The formation of textured MIL-101 phase along [111] direction on pyridyl and hydroxyl terminated Si surfaces is observed irrespective of the synthesis condition. Isolated MIL-101crystals with preferred orientation along [111] direction was also found on acid terminated surface at excess of metal, whereas randomly oriented MIL-101 islands are observed at ratio R≧1. In contrary, no film growth happened on methyl terminated Si surfaces. Introduction of HCl, H2O and organic weak base-triethylamine into the precursor solutions also affects the formation of MOF films with various morphologies and coverage between MIL-101 and MIL-88B on carboxylic terminated Si surfaces. Time dependence of film growth at excess of ligand (R=2) and at excess of metal (R=0.5) without and with addition of HCl indicates clearly that both of MIL-88B and MIL-101 follows a Volmer-Weber growth mode, during which, isolated three-dimensional crystals or clusters formed at initial stage and grew both laterally and vertically on the surface.As to the system of Fe3+/H2NDC, depending on the synthesis conditions including temperature, ratio of ligand to [Fe3+] and [Fe3+] concentration only one phase-MIL-88C with variable surface coverage ranging from separated hexagonal crystals to layers composed of isolated bundles of hexagonal crystallites all with preferential orientation along [001] direction was observed. Evolution of MIL-88C crystals along with crystallization time also suggests a Volmer-Weber mode.Ex-situ XRD measurements of post-treatment towards the as-synthesized layers comprised of MIL-88B and MIL-88C respectively demonstrate their flexibility during molecule desorption. Tentative in-situ XRD measurements also show the reversibility of MIL-88C framework upon ethanol uptake and release.

In the diploma thesis, an overview of the existing literature focused on the thermoplastic co-extrusion method was worked out and based on the findings, extrusion of the monolayer and homogenous bodies from ZrO2, Al2O3, ZTA a ATZ was studied. For thermoplastic extrusion the capillary rheometer was modified and the nozzle was designed and fabricated. Applying the co-extrusion method, homogenous ceramic rods and monolayer rods in structure core/layer: ZrO2/Al2O3, ZrO2/ATZ and ZTA/Al2O3 were fabricated. In monolayer rods, the interface quality and defects that originate during preparation were evaluated. Technological parameters and properties of homogenous rods were used to rate the structure and defects in monolayer rods. Monolayer rods ZrO2/ATZ and ZTA/Al2O3 with 2.5 mm diameter and 45 mm length (containing small defects) were prepared by thermoplastic co-extrusion.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19898号 / 工博第4214号 / 新制||工||1651(附属図書館) / 32975 / 京都大学大学院工学研究科材料化学専攻 / (主査)教授 木村 俊作, 教授 瀧川 敏算, 教授 今堀 博 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20702号 / 工博第4399号 / 新制||工||1683(附属図書館) / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 杉村 博之, 教授 河合 潤, 教授 邑瀬 邦明 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

No description available.