Préparation des fibres orientées et nanostructurées de polymères conjugués semiconducteurs à structure Shish Kebab

Le poly(3-hexylthiophène) régiorégulier (rr-P3HT) est l’un des matériaux phare pour les applications en électronique plastique. Afin d’améliorer les performances des dispositifs, il est important de comprendre et de contrôler la structure et la morphologie de la couche active. Des films minces de rr-P3HT cristallins et orientés peuvent être obtenus par epitaxie directionnelle par cristallisation (DEC) de 1,3,5-trichlorobenzène (TCB). Dans ce travail de thèse, nous présentons les avantages de la méthode DEC pour (i) déterminer la structure cristalline du rr-P3HT et pour (ii) étudier les fibres « shish-kebab », une morphologie alternative du rr-P3HT. La première partie de ce manuscrit consiste en l’analyse structurale par diffraction électronique de la forme I du P3HT obtenue dans les films epitaxiés. Afin d’affiner le modèle structural, nous avons fait varier la conformation des chaînes latérales. Dans un deuxième temps, nous avons appliqué ce même protocole afin de résoudre la structure du second polymorphe du P3HT (forme II) grâce à l’obtention de monocristaux parself-seeding. La deuxième partie du manuscrit est consacrée à l’élaboration de fibres orientées dites en « shish-kebab » par épitaxie dans un mélange TCB/Pyridine. La cinétique de croissance ainsi que l’orientation des chaînes de P3HT sont étudiés afin d’optimiser la méthode de préparation des fibres. L’effet de la masse moléculaire sur leur formation a également été évalué. Finalement les propriétés de transport de charges au sein de ces fibres ont été étudiées grâce à l’élaboration de transistors à effet de champ.Regioregular poly(3-hexylthiophene) (rr-P3HT) is one of the promising materials for plastic electronic applications. Understanding as well as controlling the structure and morphology of the active layer is essential to improve the device efficiency. Highly crystalline and highly oriented rr-P3HT thin films can be obtained via directional epitaxial crystallization (DEC) in 1,3,5-trichlorobenzene (TCB). In this dissertation, we present the benefits of DEC method to (i) determine the crystal structure of rr-P3HT and (ii) to study shish-kebab fibers, an alternative morphology of rr-P3HT. The first part of this dissertation is related to the structural analysis of rr-P3HT form-I by using electron diffraction analysis on the epitaxied film. Furthermore, the modification of side chain conformation is used to improve the structural model. Finally, the determination protocol is also applied to resolve the preliminary crystal structure of rr-P3HT form II prepared by self-seeding method. The second part of thisdissertation is related to highly oriented shish-kebab fibers of rr-P3HT prepared by epitaxial crystallization in a mixture of TCB and pyridine. The investigations of growth kinetics and orientation of P3HT chains in the fiber are performed in order to determine the optimization of preparation conditions and growth mechanism of the fibers. In addition, the effect of molecular weight on the formation of the fibers is investigated. Finally, the charge transport properties of the fibers are measured by using the field effect transistor configuration

Préparation des fibres orientées et nanostructurées de polymères conjugués semiconducteurs à structure Shish Kebab

Le poly(3-hexylthiophène) régiorégulier (rr-P3HT) est l’un des matériaux phare pour les applications en électronique plastique. Afin d’améliorer les performances des dispositifs, il est important de comprendre et de contrôler la structure et la morphologie de la couche active. Des films minces de rr-P3HT cristallins et orientés peuvent être obtenus par epitaxie directionnelle par cristallisation (DEC) de 1,3,5-trichlorobenzène (TCB). Dans ce travail de thèse, nous présentons les avantages de la méthode DEC pour (i) déterminer la structure cristalline du rr-P3HT et pour (ii) étudier les fibres « shish-kebab », une morphologie alternative du rr-P3HT. La première partie de ce manuscrit consiste en l’analyse structurale par diffraction électronique de la forme I du P3HT obtenue dans les films epitaxiés. Afin d’affiner le modèle structural, nous avons fait varier la conformation des chaînes latérales. Dans un deuxième temps, nous avons appliqué ce même protocole afin de résoudre la structure du second polymorphe du P3HT (forme II) grâce à l’obtention de monocristaux parself-seeding. La deuxième partie du manuscrit est consacrée à l’élaboration de fibres orientées dites en « shish-kebab » par épitaxie dans un mélange TCB/Pyridine. La cinétique de croissance ainsi que l’orientation des chaînes de P3HT sont étudiés afin d’optimiser la méthode de préparation des fibres. L’effet de la masse moléculaire sur leur formation a également été évalué. Finalement les propriétés de transport de charges au sein de ces fibres ont été étudiées grâce à l’élaboration de transistors à effet de champ.Regioregular poly(3-hexylthiophene) (rr-P3HT) is one of the promising materials for plastic electronic applications. Understanding as well as controlling the structure and morphology of the active layer is essential to improve the device efficiency. Highly crystalline and highly oriented rr-P3HT thin films can be obtained via directional epitaxial crystallization (DEC) in 1,3,5-trichlorobenzene (TCB). In this dissertation, we present the benefits of DEC method to (i) determine the crystal structure of rr-P3HT and (ii) to study shish-kebab fibers, an alternative morphology of rr-P3HT. The first part of this dissertation is related to the structural analysis of rr-P3HT form-I by using electron diffraction analysis on the epitaxied film. Furthermore, the modification of side chain conformation is used to improve the structural model. Finally, the determination protocol is also applied to resolve the preliminary crystal structure of rr-P3HT form II prepared by self-seeding method. The second part of thisdissertation is related to highly oriented shish-kebab fibers of rr-P3HT prepared by epitaxial crystallization in a mixture of TCB and pyridine. The investigations of growth kinetics and orientation of P3HT chains in the fiber are performed in order to determine the optimization of preparation conditions and growth mechanism of the fibers. In addition, the effect of molecular weight on the formation of the fibers is investigated. Finally, the charge transport properties of the fibers are measured by using the field effect transistor configuration

Préparation des fibres orientées et nanostructurées de polymères conjugués semiconducteurs à structure Shish Kebab

Le poly(3-hexylthiophène) régiorégulier (rr-P3HT) est l un des matériaux phare pour les applications en électronique plastique. Afin d améliorer les performances des dispositifs, il est important de comprendre et de contrôler la structure et la morphologie de la couche active. Des films minces de rr-P3HT cristallins et orientés peuvent être obtenus par epitaxie directionnelle par cristallisation (DEC) de 1,3,5-trichlorobenzène (TCB). Dans ce travail de thèse, nous présentons les avantages de la méthode DEC pour (i) déterminer la structure cristalline du rr-P3HT et pour (ii) étudier les fibres shish-kebab , une morphologie alternative du rr-P3HT. La première partie de ce manuscrit consiste en l analyse structurale par diffraction électronique de la forme I du P3HT obtenue dans les films epitaxiés. Afin d affiner le modèle structural, nous avons fait varier la conformation des chaînes latérales. Dans un deuxième temps, nous avons appliqué ce même protocole afin de résoudre la structure du second polymorphe du P3HT (forme II) grâce à l obtention de monocristaux parself-seeding. La deuxième partie du manuscrit est consacrée à l élaboration de fibres orientées dites en shish-kebab par épitaxie dans un mélange TCB/Pyridine. La cinétique de croissance ainsi que l orientation des chaînes de P3HT sont étudiés afin d optimiser la méthode de préparation des fibres. L effet de la masse moléculaire sur leur formation a également été évalué. Finalement les propriétés de transport de charges au sein de ces fibres ont été étudiées grâce à l élaboration de transistors à effet de champ.Regioregular poly(3-hexylthiophene) (rr-P3HT) is one of the promising materials for plastic electronic applications. Understanding as well as controlling the structure and morphology of the active layer is essential to improve the device efficiency. Highly crystalline and highly oriented rr-P3HT thin films can be obtained via directional epitaxial crystallization (DEC) in 1,3,5-trichlorobenzene (TCB). In this dissertation, we present the benefits of DEC method to (i) determine the crystal structure of rr-P3HT and (ii) to study shish-kebab fibers, an alternative morphology of rr-P3HT. The first part of this dissertation is related to the structural analysis of rr-P3HT form-I by using electron diffraction analysis on the epitaxied film. Furthermore, the modification of side chain conformation is used to improve the structural model. Finally, the determination protocol is also applied to resolve the preliminary crystal structure of rr-P3HT form II prepared by self-seeding method. The second part of thisdissertation is related to highly oriented shish-kebab fibers of rr-P3HT prepared by epitaxial crystallization in a mixture of TCB and pyridine. The investigations of growth kinetics and orientation of P3HT chains in the fiber are performed in order to determine the optimization of preparation conditions and growth mechanism of the fibers. In addition, the effect of molecular weight on the formation of the fibers is investigated. Finally, the charge transport properties of the fibers are measured by using the field effect transistor configuration.STRASBOURG-Bib.electronique 063 (674829902) / SudocSudocFranceF

The Decoration of ZnO Nanoparticles by Gamma Aminobutyric Acid, Curcumin Derivative and Silver Nanoparticles: Synthesis, Characterization and Antibacterial Evaluation

Zinc oxide nanoparticles (ZnO NPs) are applied in various applications in catalysis, biosensing, imaging, and as antibacterial agents. Here we prepared ZnO nanomaterials decorated by γ-aminobutyric acid (GABA), curcumin derivatives (CurBF2) and silver nanoparticles (CurBF2-AgNPs). The structures of all ZnO nanostructures were characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), UV–VIS spectrophotometry, fluorescence spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HR-TEM). Further, their antibacterial activities against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were investigated through analysis of minimum inhibitory concentration (MIC) method. Among the prepared nanostructures, the ZnO NPs-GABA/CurBF2-AgNPs showed excellent antibacterial activity against both Gram-positive and Gram-negative bacteria. ZnO NPs fabricated here may have potential use in future anti-bacterial compositions and coatings technologies

Structural Models of Poly(cyclopentadithiophene-<i>alt</i>-benzothiadiazole) with Branched Side Chains: Impact of a Single Fluorine Atom on the Crystal Structure and Polymorphism of a Conjugated Polymer

This study describes the impact of a single fluorine atom substitution in the conjugated backbone of poly­(cyclo­penta­di­thiophene-<i>alt</i>-benzo­thia­diazole) on the structure and the polymorphism of the polymer bearing 2-ethylhexyl side chains. Controlled growth of the nonfluorinated and fluorinated polymers by solvent vapor annealing (SVA), melt-crystallization on oriented poly­(tetrafluoroethylene), and high-temperature rubbing yield highly crystalline and/or oriented films of a thermodynamically stable polymorph called form I. The single-crystal <i>hk</i>0 and the oriented fiber patterns are obtained in films prepared by SVA and aligned films, respectively. Form I involves a high-symmetry packing of four chains in an orthorhombic cell (<i>Pccn</i> space group) with pseudohexagonal symmetry. The chains are paired into dimers with a 3.6–3.8 Å interchain π-stacking distance and a segregated mode of stacking of cyclo­penta­di­thiophene and benzo­thiadiazole (BT). A single H/F substitution on the BT unit modifies the orientation of the dimers in the unit cell of form I. Absorption and structural properties of this new polymorph are discussed with respect to the classical π-stacking structure obtained from solvent-additive processed films. Evidence of yet another polymorph (form II) highlights the polymorphism of these alternated donor–acceptor copolymers

Synthesis and Characterization of Sequence-Controlled Semicrystalline Comb Copolymers: Influence of Primary Structure on Materials Properties

Sequence-controlled semicrystalline copolymers were prepared by nitroxide-mediated copolymerization of a large excess of octadecylstyrene with small amounts of functional N-substituted maleimides (i.e., <i>N</i>-(<i>n</i>-propyl)­maleimide, <i>N</i>-benzylmaleimide, pentafluorophenyl 4-maleimidobenzoate, 4-(<i>N</i>-maleimido)­azobenzene, <i>N</i>-(1-pyrenyl)­maleimide, and <i>N</i>-(2-(amino-BOC)­ethylene)­maleimide). These copolymers were prepared in bulk at 110 °C using the commercial alkoxyamine BlocBuilder MA as initiator and control agent. Time-controlled additions protocols were used to place the N-substituted maleimides at precise chain location along the poly­(octadecylstyrene) backbones. Size exclusion chromatography and ¹H NMR studies indicated that well-defined copolymers with controlled monomer sequences, composition, chain length, and molecular weight distribution were formed in all cases. Although possessing an atactic backbone, these polymers exhibit a semicrystalline behavior. The electron diffraction method indicated that the octadecyl side chains form lamellar phases. Moreover, differential scanning calorimetry studies evidenced a melting temperature in the range 40–45 °C and a crystallization temperature around 30–35 °C. It was observed that melting is influenced by the composition and sequence distribution of the copolymers. Thus, small microstructural variations allow a precise control over order–disorder transitions

Structural Characterization of Highly Oriented Naphthalene-Diimide-Bithiophene Copolymer Films via Vibrational Spectroscopy

Epitaxially grown highly oriented crystalline films, named form I and form II, and spin-coated films of poly­{[<i>N</i>,<i>N</i>′-bis­(2-octyldodecyl)-naphthalene-1,4,5,8-bis­(dicarboximide)-2,6-diyl]-<i>alt</i>-5,5′-(2,2′-bithiophene)}, P­(NDI2OD-T2), have been investigated through infrared vibrational spectroscopy techniques (infrared absorption in double transmission at normal incidence (IRA-TR) and reflection absorption infrared spectroscopy at grazing angle incidence (RAIRS)) to get access to polymer chain orientation and structure. An analytic model to correlate the experimental intensities of the IR bands with structural parameters has been developed and applied for the three film morphologies. While spin-coated and form I films show P­(NDI2OD-T2) chains lying parallel to the substrate in the face-on arrangement, form II films feature a structure with chains tilted out from the surface. The combined experimental and theoretical methodology gives insights into the local molecular orientations of naphthalene diimide (NDI2OD) and bithiophene (T2) counits. This approach can be easily extended to a variety of organic polymer semiconductors, allowing one to directly correlate molecular structure to properties such as charge transport, which is of fundamental relevance for developing quantitative models for applications in organic electronics and photovoltaics

Controllable processes for generating large single crystals of poly(3-hexylthiophene)

peer reviewe

Controlling the Growth of Silver Nanoparticles on Thin Films of an n‑Type Molecular Semiconductor

Nucleation and growth of silver nanoparticles were studied on the surface of an n-type organic semiconductor (<i>N</i>,<i>N</i>′-bis­(<i>n</i>-octyl)­dicyanoperylene-3,4:9,10-bis­(dicarboximide) (N1400)) as a function of the deposition rate τ and the substrate temperature <i>T</i>_s. Electron tomography was used to probe the bulk diffusion of Ag in the N1400 layers. No Ag nanoparticles (NPs) are formed in the bulk of N1400 even for high substrate temperatures, <i>T</i>_s = 125 °C, indicating that Ag diffusion in the organic semiconductor is marginal. The NP distribution on the surface of N1400 is essentially determined by the surface roughness of the N1400 films. A transition in the nucleation mode of Ag NPs on N1400 is evidenced as a function of <i>T</i>_s: for <i>T</i>_s ≤ 50 °C, Ag NPs form random patterns, whereas, for <i>T</i>_s ≥ 75 °C, linear arrays of aligned NPs are observed. Such arrays result from step edge decoration of the N1400 terraces. The surface density of Ag NPs is thermally activated, but the activation energy depends on the structure of the N1400 films: the smaller the crystal size of the N1400 grains, the larger the activation energy

High-Temperature Rubbing: A Versatile Method to Align π‑Conjugated Polymers without Alignment Substrate

Mechanical rubbing of polymer films has been widely used in the liquid crystal display industry to prepare oriented alignment layers of polyimides. We show that this fast orientation method can be successfully applied to a large palette of different π-conjugated systems, i.e., p- and n-type semiconducting homopolymers and alternating copolymers. Transmission electron microscopy, grazing incidence X-ray diffraction and UV–vis absorption spectroscopy reveal that both, the temperature of the films during rubbing and the molecular weight of the polymer strongly influence the level of orientation. For polythiophenes and polyfluorenes, the dependence of the orientational order parameter on the rubbing temperature (<i>T</i>_rub) was determined. A strong increase of alignment with <i>T</i>_rub is explained by the progressive alignment of higher molecular weight fractions at higher <i>T</i>_rub. The disordering of alkyl side chains allows the hairy-rod shaped macromolecules to disentangle and align during rubbing. In addition, for certain conjugated polymers, the in-plane orientation, crystallinity, and polymorphism of the rubbed films can be substantially improved/modified by postdeposition thermal or solvent vapor annealing. This high level of orientation results in highly anisotropic optical and electronic properties (UV–vis absorption, fluorescence, charge transport)