Dissertations / Theses on the topic 'Flexible MOF'

Die Entwicklung und Synthese im Bereich neuartiger poröser Systeme, im speziellen Metallorganische Gerüstverbindungen (engl.: Metall-organic Frameworks; MOFs), wird weltweit in vielen Forschergruppen intensiv bearbeitet. Aufgrund der Möglichkeit, dass sich die Materialeigenschaften individuell designen lassen und letztendlich spezifische Eigenschaften für eine ausgewählte Anwendung bereitgestellt werden können, stellen MOFs für einen weiten Forscherkreis eine interessante Materialienklasse dar. Im Rahmen dieser Arbeit stand die Synthese von neuartigen MOFs im Vordergrund, welche geeignete Eigenschaften für eine effiziente Speicherung von Gasen im Nieder- als auch im Hochdruckbereich besitzen. Dabei wurde zum einen Augenmerk auf die Synthese mesoporöser MOF-Systeme gelegt. Hier lag die größte Herausforderung darin, die erhaltenen hochporösen Materialien in einer stabilen gastfreien Form zu erhalten. Ein weiterer Schwerpunkt war die Untersuchung von flexiblen MOF-Verbindungen und deren Eigenschaften in Abhängigkeit der Synthesebedingungen und der adsorbierten Spezies. Auf Basis der Copolymerisation verschiedener multifunktioneller Linkermoleküle konnten zwei mesoporöse Verbindungen und dazugehörige Isomorphe synthetisiert werden (DUT-6, DUT-23; DUT = Dresden University of Technology). Mit diesen Verbindungen konnte über die Kombination von unterschiedlich funktionellen Linkermolekülen eine erhöhte Netzwerkstabilität und damit einhergehend erhöhte Porosität erhalten werden. Sämtliche Verbindungen zeigen ausgezeichnetes adsorp-tives Verhalten und können aufgrund ihrer verschiedenen Eigenschaften in Bereichen der Hochdruckadsorption, Katalyse oder enantioselektiven Trennung Einsatz finden. Im zweiten Teil der Arbeit wurde das flexible Verhalten der „pillar-layer“ Verbindungen DUT-8(M) (M = Ni, Co, Zn, Cu) näher untersucht. Diese isomorphe Reihe zeichnet sich durch ihre hohe Netzwerkflexibilität in Abhängigkeit der integrierten Gastmoleküle sowie dem vorliegendem Metall-Dimer aus. DUT-8(M) zeigt unterschiedliche Adsorptionseigenschaften und unterschiedliches Stabilitäts- sowie Flexibilitätsverhalten.

Advances in flexible and functional metal–organic frameworks (MOFs), also called soft porous crystals, are reviewed by covering the literature of the five years period 2009–2013 with reference to the early pertinent work since the late 1990s. Flexible MOFs combine the crystalline order of the underlying coordination network with cooperative structural transformability. These materials can respond to physical and chemical stimuli of various kinds in a tunable fashion by molecular design, which does not exist for other known solid-state materials. Among the fascinating properties are so-called breathing and swelling phenomena as a function of host–guest interactions. Phase transitions are triggered by guest adsorption/desorption, photochemical, thermal, and mechanical stimuli. Other important flexible properties of MOFs, such as linker rotation and sub-net sliding, which are not necessarily accompanied by crystallographic phase transitions, are briefly mentioned as well. Emphasis is given on reviewing the recent progress in application of in situ characterization techniques and the results of theoretical approaches to characterize and understand the breathing mechanisms and phase transitions. The flexible MOF systems, which are discussed, are categorized by the type of metal-nodes involved and how their coordination chemistry with the linker molecules controls the framework dynamics. Aspects of tailoring the flexible and responsive properties by the mixed component solid-solution concept are included, and as well examples of possible applications of flexible metal–organic frameworks for separation, catalysis, sensing, and biomedicine.

Metal-Organic Frameworks (MOFs) are a class of synthetic porous crystalline materials based on metal ions connected through spacing ligands. They possess interesting properties such as, high porosity, high concentration of metal centers, flexibility, etc., which are difficult to find in conventional porous materials. As a result of these unique features, MOFs can maintain porous structures upon removal, inclusion, exchange, or reaction of a wide selection of molecular guests, making them useful for applications in selective gas adsorption/separation. Furthermore, a number of MOFs have the ability to respond to specific stimuli such as host-guest interactions, temperature or pressure change, light, etc. To date, most of the applications of these flexible MOFs is related to gas-storage and selective adsorption/separation, but it was soon recognized that the responsive properties of these materials have enormous potential in many areas, a really interesting example are NPs@MOFs composites which can be used to design novel “smart” heterogeneous catalysts capable of reversibly adapt to substrates and/or respond to regulating stimuli (e.g. reversible structural transitions upon adsorption of guest molecules). The work within this thesis is divided into two parts. The first one focuses on the understanding of the host-guest interactions during adsorption processes in highly stable, rigid, porous metal-organic frameworks. of formula Fe2(BDP)3x(BDP-NH2)3(1-x) (x = 0, 0.5, 1) with H2BDP-NH2 = 2-amino[1,4-bis(1Hpyrazol- 4-yl)benzene]. Their investigation was performed through a multi-technique approach exploiting high-resolution powder X-ray diffraction (HR-PXRD), advanced gas adsorption measurements and Monte Carlo simulations. In particular, the host-guest interactions during CO2 adsorption were studied via in situ HR-PXRD dosing CO2 in certain pressure ranges at different temperatures and compared between functionalized and bare systems. Rietveld refinements of the diffraction data collected at each pressure point was used to understand the preferential adsorption sites occupied by the gaseous probe and the host–guest interactions, as well as the breathing behaviour, whose mechanism was not yet completely described in the literature. The metal ion and ligand functionalization modulate the sorption properties of these materials, enhancing their affinity to CO2 molecules. Finally, new flexible, multivariate MOFs of general formula Zn(BDP)0.5(BDP-X)0.5 (X = NH2 or NO2) were synthesized. The deep characterization of the adsorption properties and the structural features of these materials will be crucial to understand the relation between the structural flexibility, functionalization degree and crystal size, with the gas adsorption and separation properties. The second part of this thesis describes a family of pillar-layered MOFs of general formula [M2(fubdc) 2P]n with M2+ = Zn2+, fu-bdc2- = diversely functionalised 1,4-benzenedicarboxylate) and how catalytically inert nanoparticles (silica NPs, 30 nm) can be embedded into the microporous ordered MOFs structures, obtaining hybrid materials where the NPs represent typically a meso-scale “defect” or “heterogeneity” to the system. In particular, the work was focused on the comparison between the plain MOFs and the new composite materials NPs@MOF. The parent [Zn2(bdc)2(dabco)]n is only weakly flexible, whereas the substituted frameworks [Zn2(fu-bdc)2(dabco)]n (with fu = DM, 2,5-bis(methoxy)- 1,4-benzenedicarboxylate or BME, 2,5-bis(2-methoxyethoxy)-1,4-benzenedicarboxylate) contract significantly upon guest removal to a narrow pore (np) form and expand again (lp form) upon adsorption of DMF, EtOH, or CO2, etc. In contrast, N2 is hardly adsorbed and does not open the narrow pore form. These “breathing” dynamics are attributed to the dangling side chains present on the linkers, which interact with mobile guest molecules as well as with themselves and with the framework backbone. The samples were characterized by a variety of techniques: PXRD, FTIR, TGA, DSC, EFTEMEDX, TEM tomography, UV-Vis and PL spectroscopy, standard N2 (77 K) and CO2 (195 K) gas adsorption experiments with the objective of understanding the connection between defects, disorder with flexibility. The in‐depth and in situ structural and spectroscopic characterization carried out, especially gas adsorption and variable temperature PXRD experiments, revealed interesting differences in the flexible behaviour between the parent MOFs and the NPs@MOFs.

Flexible metal-organic frameworks (MOFs) are capable of changing their crystal structure as a function of external stimuli such as pressure, temperature, and type of adsorbed guest species. DUT-49 is the first MOF exhibiting structural transitions accompanied by the counterintuitive phenomenon of negative gas adsorption (NGA). Here, we present high pressure in situ ¹²⁹Xe NMR spectroscopic studies of a novel isoreticular MOF family based on DUT-49. These po-rous materials differ only in the length of their organic linkers causing changes in pore size and elasticity. The series encompasses both, purely microporous materials as well as materials with both, micropores and small mesopores. The chemical shift of adsorbed xenon depends on xenon-wall interactions and thus, on the pore size of the material. The xenon adsorption behavior of the different MOFs can be observed over the whole range of relative pressure. Chemical shift adsorption/desorption isotherms closely resembling the conventional, uptake-measurement based isotherms were obtained at 237 K where all materials are rigid. The comparable chemical environment for adsorbed xenon in these isoreticular MOFs allows establishing a correlation between the chemical shift at a relative pressure of p/p₀ = 1.0 and the mean pore diameter. Furthermore, the xenon adsorption behavior of the MOFs is studied also at 200 K. Here, struc-tural flexibility is found for DUT 50, a material with an even longer linker than the previously known DUT-49. Its structural transitions are monitored by ¹²⁹Xe NMR spectroscopy. This compound is the second known MOF showing the phenomenon of negative gas adsorption. Further increase in the linker length results in DUT-151, a material with interpenetrated network topology. In situ ¹²⁹Xe NMR spectroscopy proves that this material exhibits another type of flexibility compared to DUT-49 and DUT-50. Further surprising observations are made for DUT-46. Volumetric xenon adsorption measurements show that this non-flexible microporous material does not exhibit any hysteresis. In contrast, in situ ¹²⁹Xe NMR spectroscopically detected xenon chemical shift isotherms exhibit a hysteresis even after longer equilibration times than in the volumetric experiments. This indicates kinetically hindered re-distribution processes and long-lived metastable states of adsorbed xenon within the MOF persisting at the time scale of hours or longer.

Es wurden verschiedene NMR-spektrokopische Messungen an flexiblen und chiralen MOFs durchgeführt. Zur Untersuchung der Porensysteme kamen 129Xe-NMR und 13C-NMR an adsorbiertem CO2 zum Einsatz, während die MOF-Gitter und ihre Wechselwirkungen mit adsorbierten Gastmolekülen mittels 13C- und 1H-MAS-NMR-Spektroskopie studiert wurden. Während DUT-8(Ni) Flexibilität zeigt, weist DUT-8(Cu) ein starres Gitter auf. Die Flexibilität der sogenannten Solid-Solutions hängt in ausgeprägter Weise vom Verhältnis der funktionalisierten bdc-Linker 2,5-bme-bdc und db-bdc ab. Dieses Verhältnis hat zudem einen großen Einfluss auf die Orientierung der adsorbierten CO2-Moleküle. Es wurde erstmals eine Methode vorgestellt, die den Festkörper-NMR-spektroskopischen Nachweis chiraler Seitengruppen in chiralen MOFs erlaubt, wie anhand des chiral modifizierten UMCM-1 (ChirUMCM-1) demonstriert wurde. Die Chiralität kann einen NMR-spektroskopisch messbaren Einfluss auf die intrinsische Dynamik des MOF-Gitters ausüben, wie am chiral modifizierten DUT-32 deutlich wurde, dessen chirale Seitengruppe selektiv 15N- und 13C-isotopenmarkiert wurde.

L'attività di ricerca si è occupata della progettazione, sintesi e caratterizzazione di materiali porosi. Diverse linee di ricerca sono state perseguite. Materiali porosi per l'assorbimento selettivo e lo stoccaggio di gas. Le proprietà di una serie di polimeri porosi organici sono state studiate attraverso misure di assorbimento di gas e misure di risonanza magnetica nucleare dello stato solido in presenza di una fase gassosa per comprendere la natura delle interazioni tra le molecole ospiti e le pareti dei canali. In particolare, si è verificata l'elevata energia di interazione tra le molecole di anidride carbonica e gruppi amminici alifatici che genera un'efficiente trasferimento di magnetizzazione tra gli idrogeni del gruppo amminico e il carbonio dell'anidride carbonica. Polimeri iper-reticolati porosi e polimeri organici porosi sono stati studiati mediante assorbimento di metano ad alta pressione (fino a 180 bar) per possibili applicazioni per lo stoccaggio di gas naturale in presenza di reticoli porosi (ANG). Durante il periodo all'estero presso il Bernal Institute sotto la supervisione del Prof. M.J. Zaworotko mi sono occupato dello sviluppo di una serie di framework metallo-organici che presentano flessibilità strutturale. In presenza di un opportuno gas o vapore i reticoli sintetizzati danno luogo a una transizione di fase tra una fase compatta e una fase porosa in maniera repentina. Questo meccanismo è attualmente molto studiato per le possibili applicazioni nell'ambito dello stoccaggio e separazione dei gas. Reticoli metallo-organici contenenti rotori molecolari. Due nuovi reticoli porosi metallo-organici sono stati sviluppati e le loro proprietà di assorbimento e termiche sono state caratterizzate. Inoltre, i due sistemi contengono un rotore molecolare molto mobile anche alle basse temperature come dimostrato da esperimenti di risonanza magnetica nucleare dello stato solido. Materiali porosi per applicazioni nella fotonica. Sono stati sintetizzati alcuni materiali organici covalenti contenenti difenilantracene. Questi campioni presentano elevata resa quantica di fotoluminescenza. In dispersione e in presenza di un sensibilizzatore opportuno questi materiali danno vita ad un fenomeno di up-conversion dovuto all'annichilazione di tripletto con efficienze fino al 15 %. Inoltre, legando chimicamente il sensibilizzatore al reticolo poroso è possibile ottenere dei sistemi per up-conversion autonomi. Infine, nanocristalli di reticoli metallo-organici porosi sono stati cresciuti e le loro proprietà di foto- e radioluminescenza sono state investigate approfonditamente. Inoltre, questi cristalli, dispersi all'interno di una matrice polimerica, sono stai utilizzati per sviluppare degli innovativi scintillatori ibridi per la rivelazione di raggi x e gamma.
The research activity focused on the design, synthesis and characterization of porous organic and hybrid materials. Porous materials for selective gas adsorption and storage. Tailored porous organic frameworks bearing different functional groups have been investigated via gas adsorption analyses and in situ spectroscopic techniques to understand the interaction between the guest phase and the primary adsorption sites installed on pore walls. Specifically, aliphatic amines interact strongly with carbon dioxide molecules resulting in an isosteric heat of adsorption as high as 54 kJ/mol at low loading and this close-contact interaction has been characterized with 2D heterocorrelated NMR sppectroscopy. Hyper.crosslinked polymers and porous organic frameworks have been synthetized and their performance towards high pressure (up to 180 bar) methane adsorption have been evaluated to assess their potential applications in adsorbed natural gas technology (ANG). During a period at Bernal institute (Limerick, Ireland) under the supervision of Prof. M. J. Zaworotko, I developed novel switching metal-organic frameworks that display guest-induced phase transitions between close phases and a porous open phase. During the close to open phase transitions the coordination sphere of the zinc cations inside the structures changes from a square pyramidal to a tetrahedral geometry. Moreover, the threshold pressure for gas adsorption can be manipulated through a mixed-linker approach. These materials are currently investigated for applications in gas storage and separation. Metal-organic frameworks with intrinsic dynamics. Metal organic frameworks built up with rigid aliphatic linkers have been developed and their adsorptive and thermal properties fully characterized. These materials display ultra-fast rotational dynamic even at very low temperature. An in-depth solid state NMR study has been conducted to understand the fast rotation of the organic strut and the influence of guest species hosted inside the pores on its dynamic. Organic and hybrid materials for photonic applications. Emitting porous aromatic frameworks (ePAFs) nanoparticles containing highly fluorescent diphenylanthracene moieties have been developed. This materials display high photoluminescence quantum yield and a fast exciton diffusion inside the amorphous framework. When these nanoparticles are suspended in a solution of a suitable sensitizer the mixture display highly efficient sensitized triplet-triplet annihilation up-conversion with quantum yield up to 15 %. Moreover, PAFs with integrated sensitizers (i-ePAFs) display sensitized up-conversion working as an autonomous nanodevice. Metal-organic frameworks with diphenylanthracene units and zirconium oxo-hydroxo clusters have been developed and their luminescence and radioluminescence have been characterized. These nanocrystals have been embedded in polymeric matrixes to generate efficient and innovative scintillating materials with fast response for x-ray and gamma-ray detection.

A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich

A flexible Metal–Organic Framework Zn4O(BenzTB)3/2 (DUT-13) was obtained by combination of a tetratopic linker and Zn4O6+ as connector. The material has a corundum topology and shows the highest pore volume among flexible MOFs.
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

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Ce travail décrit l'étude de différents paramètres qui influent sur les propriétés d'adsorption de composés poreux organométalliques (MOFs). Nous avons utilisé les techniques de volumétrie et de gravimétrie d'adsorption et les systèmes adsorbables sont la série des alcanes linéaires (du n-pentane au n-nonane). Les solides étudiés sont les MIL-47(V), MIL-53(Cr, Al, Fe), les MIL-53(Fe)-X modifiés et la série MIL-88(Fe)-A, B, C. Parmi les nombreuses conclusions de cette étude, nous pouvons en détailler plusieurs : (i) la flexibilité des MIL-53(Cr, Al, Fe), rendue possible par la présence de µ2-OH coordinés aux centres métalliques, dépend de l'identité des centres métalliques et de celle de l'adsorbable. (ii) la modification chimique, par substitution d'un atome d'hydrogène porté par les noyaux aromatiques des ligands, induit une variation dans le degré de flexibilité des structures et dans la stabilité des différentes phases. (iii) la nature des ligands, dans la série des MIL-88(Fe), en termes de nombre de noyaux aromatiques constituent les ligands, modifie les interactions physiques au sein des réseaux organométalliques ce qui a un effet sur leur stabilité et leur flexibilité.(iv) la facilité de la diffusion des alcanes linéaires, de longueur différente, dans les pores des solides dépend notamment des points développés ci-dessus
This study describes a study of the adsorptive properties of several flexible porous organometallic frameworks (MOFs) using the volumetric and gravimetric methods and apolar normal alkanes (n-pentane to n-nonane) as adsorbate molecules. The materials studied are MIL-47(V), MIL-53(Cr, Al, Fe), the modified MIL-53(Fe)-X and the MIL-88(Fe)-A, B, C.This allows the study of different parameters on the behaviour of the solids during the adsorption process. Amongst the findings of this study, several can be emphasized :(i) the flexibility of the MIL-53(Cr, Al, Fe), made possible by the presence of µ2-OH coordinated to the metal centres, depends on the identity of the metal centres and that of the adsorbate.(ii) the chemical modification by the substitution of a hydrogen atom on the aromatic ligands of the MIL-53(Fe) induces a change in the degree of flexibility of the framework and the stability of the various phases.(iii) the nature of the ligands in the MIL-88(Fe) series, in terms of the number of the aromatic rings comprising the linker, changes the physical interactions within the framework and thus its stability and flexibility.(iv) the ease of diffusion into the pores of the alkanes of various alkyl chain length depends on the three points mentioned above

CdTe solar cells in the superstrate configuration have achieved record efficiencies of 16% but those in the substrate configuration have reached efficiencies of only 7.8%. A major reason for the lower efficiency of substrate CdTe solar cells is the poor back contact. In this work, CdTe solar cells of the substrate configuration have been fabricated on flexible metallic substrates. For this type of devices, impurity diffusion out of stainless-steel substrates due to high temperature processing can be a cause for poor cell performance. It is necessary to investigate ways of improving the back contact by trying to mitigate the above factors. In this work, Nitrogen has been incorporated in Molybdenum by RF magnetron sputtering. Nitrogen incorporation has helped achieve a 2% increase in efficiency for the best cell and an improvement of 1.5% on an average.

Les matériaux hybrides de type MOFs sont des solides poreux dans lesquels des centres métalliques sont reliés entre eux par des ligands organiques. Il est possible, non seulement de faire varier la taille et la géométrie de leurs porosités, mais aussi de moduler leurs compositions chimiques en modifiant à la fois la nature de la brique inorganique et des groupements sur le ligand organique. Cette nouvelle famille de matériaux a fait l'objet d'une attention particulière ces dernières années pour des applications potentielles dans différents domaines à fort intérêt socio-économique comme le captage ou la séparation de gaz ou bien encore la catalyse. Au-delà d'une stabilité chimique et thermique, ces matériaux doivent être aussi suffisamment résistants mécaniquement pour s'adapter au mieux aux contraintes de l'application visée (mise en forme de l'échantillon, conditions opératoires….). Il est donc impératif de connaître les propriétés mécaniques de ces nouveaux matériaux, sujet qui n'a fait l'objet à ce jour que de très peu d'études. L'objectif de ce travail est donc de mettre en œuvre des mesures de diffraction des rayons X et neutrons sur grands instruments afin de caractériser dans un premier temps le comportement structural du matériau flexible MIL-53 (MIL pour Matériaux de l'Institut Lavoisier) sous l'application d'une pression mécanique modérée (P~1 GPa) en fonction de la nature du métal (Al,Cr) et de la fonction greffée sur le ligand organique (-H, -Cl, -CH3). Ces données expérimentales sont ensuite discutées à partir de résultats issus de la simulation moléculaire. L'étape suivante consiste à étudier l'effet du confinement de molécules de solvants dans les pores de ce solide sur la transition structurale du réseau hôte. Enfin, deux familles de MOFs rigides, la MIL-125(Ti) et l'UiO-66(Zr) (UiO pour Unversité d'Oslo) sont considérées afin de caractériser non seulement leur domaine de stabilité mécanique en pression (Pmax~ 5 GPa) mais aussi leur compressibilité. Les résultats ainsi obtenus sont comparés aux performances mécaniques des meilleurs MOFs
Metal Organic Framework (MOF) materials have been the focus of intense research activities over the past 10 years, with the emergence of a wide range of novel architectures, constructed from inorganic clusters linked by organic moieties. In order to maintain their useful functionalities and high performances in the different fields explored so far (gas storage/separation, catalysis, sensors and many others), besides high chemical and thermal stabilities, MOFs must be also stable enough to resist to different mechanical constraints in both processing and applications. Indeed, there is nowadays a growing interest to characterize the mechanical behaviours of this class of materials under moderate and high applied pressure. This work first aimed to probe the pressure dependence of the structural behaviour of the highly flexible MIL-53 system [MIL stands for Materials of Institut Lavoisier] as a function of the nature of (i) the metal center (Al,Cr) and (ii) the functional group grafted on the organic linker (-H,-Cl,-CH3) using a combination of high-pressure x-ray/neutron diffraction and molecular simulations. The same methodology was further applied to probe how the presence of guest molecules affects the structural transition of this class of hybrid porous solids. Finally, the mechanical stability and the compressibility of two families of rigid MOFs, the MIL-125(Ti) and the UiO-66(Zr) [UiO stands for University of Oslo] up to high pressure (P~5 GPa) have been investigated and their properties in terms of bulk modulus were compared with the most resilient MOFs reported so far

Le développement de nombreuses applications nomades, souples, déformables et sur de larges surfaces nécessite la réalisation de circuits mécaniquement flexibles, intégrant des capacités d'intéraction avec l'environnement, de communication et de traitement du signal. Une part importante de ces applications proviennent actuellement de l'industrie de l'électronique organique, mais l'apparition de nouvelles méthodes de fabrication a permis la réalisation de dispositifs à la fois souples mécaniquement et électriquement performants. En outre, les techniques de report sur substrat souple présentent de nombreux avantages (flexibilité mécanique, conservation des propriétés originelles, intégration hétérogène possible). Lors de ces travaux, une procédure d'amincissement puis de transfert sur film souple (métal, verre) des composants CMOS initialement réalisés sur des tranches SOI (silicium sur isolant) a été développée. Cette solution permet la réalisation de transistors MOS flexibles et performants possédant des fréquences caractéristiques fT/fmax de 165/188 GHz. De plus, l'utilisation d'autres matériaux que le plastique permet de modifier les propriétés originelles d'un dispositif en termes de dissipations thermiques ou de distorsions harmoniques par exemple, afin d'en améliorer les performances. La réalisation de composants souples, performants et stables a donc été démontrée
The ability to realize flexible circuits integrating sensing, signal processing, and communicating capabilities is of central importance for the development of numerous nomadic applications requiring foldable, stretchable and large area electronics. A large number of these applications currently rely on organic electronics, but new fabrication methods permitted to realize flexible mechanically and electrically efficient devices. Besides the transfert on flexible substrates offers many advantages (mechanical flexibility, preservation of original properties, possible heterogeneous integration). In this work, a solution has been developed, based on thinning and transfert onto flexible substrate (metal, glass) of high frequency (HF) CMOS devices initially patterned on conventional silicon-on-insulator (SOI) wafers. This transfer process first enables the fabrication of high performance electronics on metal, with n-MOSFETs featuring characteristic frequencies fT/fmax as high as 165/188 GHz. Secondly, the use of materials other than plastic permit to modify the original properties of a device in terms of thermal dissipation or harmonic distorsions for example, demonstrating flexibility, high performance and stability

L’électronique organique connaît depuis ces dernières années un fort développement. Le CEA LITEN dispose d’une technologie d’impression par sérigraphie de transistors de type N et de type P sur une même plaque, permettant de créer des circuits complémentaires. Les performances et les limitations de cette technologie ont été étudiées, l’un des objectifs principaux de cette thèse étant de réaliser une étude concernant la faisabilité d’une étiquette RFID entièrement réalisée en technologie organique imprimée. Une telle étiquette, en plus d’être flexible, possèderait un coût de fabrication extrêmement bas.Des blocs entiers couramment utilisés dans les circuits RFID et comportant jusqu’à 50 transistors sont conçus et testés, montrant des performances supérieures ou au niveau de l’état de l’art dans ce domaine. La technologie organique imprimée n’étant pas aussi mature que celle utilisée dans la filière semi-conductrice classique, une étude est également menée concernant les effets de la dispersion du procédé de fabrication et du vieillissement sur les performances des circuits. Des pistes seront ainsi définies sur les paramètres (fiabilité, mobilité dans les semi-conducteurs organiques, taille des dispositifs…) à améliorer pour permettre à l’électronique organique de venir concurrencer l’industrie du silicium
During the past few years, the field of organic electronics has known an important development. The CEA LITEN is able to manufacture N-type and P-type screen-printed transistors on a same plastic sheet, enabling the design of complementary circuits. The performances and limitations of this technology are studied since one of this thesis’ main objectives is to determine the feasibility of a fully-printed organic RFID tag. Such a tag would be flexible and could be manufactured at an extremely low-cost. Some circuits commonly used in the RFID tags, and using up to 50 transistors, are designed and tested, showing some performances equivalent or above the reported latest developments. The organic electronics manufacturing process is not as mature as the one used in the classical silicon industry. Therefore, a study is performed concerning the effects of this process scattering, as well as the ageing, on the circuits’ performances. The main improvements (in terms of reliability, organic semi-conductor mobility, size) that can help the organic electronics in order to compete, one day, with the silicon industry, are discussed

Le développement de nombreuses applications nomades, souples, déformables et sur de larges surfaces nécessite la réalisation de circuits mécaniquement flexibles, intégrant des capacités d‘interaction avec l‘environnement, de communication et de traitement de signal. Une part importante de ces applications provient actuellement de l‘industrie de l‘électronique organique, ou intègre des films semiconducteurs à forte mobilité sur des substrats plastiques afin d‘atteindre de meilleures performances. La combinaison de hautes performances électroniques (ondes millimétriques, faible bruit), et d‘une bonne flexibilité mécanique avec la stabilité des propriétés électroniques lors de déformations représente un des grands défis de l‘électronique future. Lors de ces travaux, une procédure d‘amincissement puis de transfert sur un film plastique des composants CMOS initiallement réalisés conventionnellement sur des tranches SOI (silicium sur isolant) a été développée. Cette solution permet la réalisation de transistors MOS flexibles et performants : possédant des fréquences caractéristiques fT/fmax de 150/160GHz et des performances en bruit NFmin/Ga de 0.57/17.8dB. De plus, positionner le plan neutre de l‘ensemble au niveau de la couche active du transistor permet de réduire les variations de propriétés électroniques à 5% même lors de déformations agressives. La réalisation de composants souples, performants et stable a ainsi été démontrée
The ability to realize flexible circuits integrating sensing, signal processing, and communicating capabilities is of central importance for the development of numerous nomadic applications requiring foldable, stretchable and large area electronics. A large number of these applications currently rely on organic electronics, or integrate high mobility active films on plastic foils to provide higher performance. A key challenge is however to combine high electrical performance (i.e. millimeter wave, low noise electronics), with the mechanical flexibility required to conform to curvilinear surfaces, in addition to high stability of these electrical performance upon deformation. In this work, a solution has been developed, based on thinning and transfer onto plastic foil of high frequency (HF) CMOS devices initially processed on conventional silicon-on-insulator (SOI) wafers. This transfer process first enables the fabrication of high performance electronics on plastic, with n-MOSFETs featuring characteristic frequencies fT/fmax as high as 150/160GHz in addition to low noise potentialities: NFmin/Ga of 0.57/17.8dB. Secondly, by locating the neutral plane of the flexible system in its active layer, the relative variation of these high frequency figures-of-merit can be limited to 5% even after aggressive bending, demonstrating flexibility, high performance and stability

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
106
In this study, inkjet printing technology was used to prepare a looped electrode composed of silver nanoparticles on a flexible polyimide (PI) film, and a porous semiconductor-type gas-sensing material such as zinc oxide and copper oxide, which were derived from a metal-organic framework material was used as sensing layer, and coated onto nanosilver loop type electrode. To investigate the sensing capability of the homemade gas sensor under reducing gas atmosphere at room temperature with a low wattage UV-LED (10 W) lamp irradiated, to improve the semiconductor gas sensitive materials need to be applied to the limitations of high-temperature environment. Using ethylene glycol as a reducing agent and polyvinylpyrrolidone (PPV) as a protective agent, silver nitrate (AgNO3) was reduced by a simple polyol reduction method to prepare nanosilver particles. X-ray diffraction (XRD) results indicate that the silver nanoparticles are spherical metal silver with face-centered cubic structure. The particle size is approximately 60-80 nm by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) and particle size analyzer. The silver nanoparticle was formulated into 5 wt% silver ink, and the ink was filled in a commercially available EPSON T50 printer ink cartridge. The nanosilver loop type electrode is printed on the polyimide film and then coated with a layer of gas sensitive material, wherein the sensing layer is ZnO (N-type) and CuO (P-type), and the formation of heterogeneous interface (P-N Junction) of ZnO mixed with CuO (ZnO/CuO) to complete the preparation of sensors. The sensors are placed in a homemade gas sensing chamber, and the sensing test is carried out under reducing gas atmosphere (0-400 ppm) at room temperature with a low wattage UV-LED (10 W) lamp irradiated. The sensors was connected to a universal meter (Keithley 2400), and the current value was read at different reducing gas concentrations. After the computer software was recorded, the sensing performance of the gas sensor at room temperature was investigated. When the sensor was used to sense 50 ppm acetone at room temperature, the response values of ZnO, CuO, and ZnO/CuO were 34.9, 20.9 and 63.6 respectively. The response time (Tres) was 3, 52 and 5 seconds respectively, the recovery time (Trec) was 5, 14 and 8 seconds, respectively, and the sensed instantaneous current value significantly changed with increasing acetone gas concentration, and was an effective acetone gas sensor. It is worth noting that sensors with heterostructure materials (ZnO/CuO) have obviously synergistic effects. Which show that the sensors can effectively improve the limitations of conventional metal oxide semiconductor gas sensors operating at high operating temperature, and have good sensing ability for the acetone gas with low ppm concentration at room temperature.

L'enjeu de cette étude est de concevoir des rubans supraconducteurs à faible coûts de production, destinés au transport de courant et la limitation de courant. Nous avons utilisé des méthodes originales et peu onéreuses comme le laminage pour l'élaboration du substrat et les méthodes de dépôt chimique « metal organic decomposition » (MOD) et « metal organic chemical vapor deposition » (MOCVD) pour la réalisation des différentes couches.
La technique MOCVD à injection s'avère particulièrement bien adaptée à la fabrication de rubans supraconducteurs car elle permet d'obtenir des couches épitaxiées d'YBCO de façon reproductible et sur de grandes longueurs. Cependant, le dépôt de couches tampon par MOCVD sur des substrats métalliques souples provoque leur oxydation et dégrade leur structure cristalline. L'utilisation combinée des techniques de dépôt MOD et MOCVD a permis de solutionner ce problème : le dépôt d'une première couche tampon de La2Zr2O7 (LZO) par MOD dans une atmosphère réductrice d'Ar + 5%H2 permet d'éviter l'oxydation du substrat et de limiter la diffusion d'O2 lors des dépôts suivants par MOCVD. Deux architectures ont été développées et caractérisées : NiWRABiTS/LZOMOD/YBCOMOCVD et NiWRABiTS/LZOMOD/CeO2MOCVD/YBCOMOCVD. L'étude de ces conducteurs a prouvé que de telles architectures permettent d'atteindre de forts courants critiques : respectivement JcLZO/LZO/YBCO = 0.8 MA/cm2 avec Ic/cm = 34 A/cm, et JcNW/LZO/CeO2/YBCO = 1.2 MA/cm2 avec Ic/cm = 54 A/cm, sur des rubans de plusieurs centimètres de long recouverts d'une couche de 800 nm d'YBCO.
Une étude TEM a permis de comprendre la croissance des couches de LZO par MOD et d'observer la formation de porosités pendant la pyrolyse des précurseurs. L'étude combinée EBSD/MO a démontré que la microstructure des substrats est transférée à la couche supraconductrice et a une influence néfaste sur la qualité du film d'YBCO. L'utilisation de couches tampons épaisses (e > 150 nm) permet d'estomper ces défauts et d'améliorer les propriétés supraconductrices des rubans.
Finalement, des essais fructueux en limitation de courant, et en transport de courant sous contrainte mécanique, ont permis de valider le procédé de fabrication des rubans pour cette application spécifique.