Nanocomposite polymère-clusters inorganiques pour la photonique intégrée : guides rubans et nanostructures-1D

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Opportunities for polymer-based nanowires in optoelectronics and nanophotonics

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Opportunities for polymer-based nanowires in optoelectronics and nanophotonics

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Transition Metal Cluster Compounds: Luminescence and Design of (nano)Composites

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Polymer-Based Nanowires and Nanotubes: nanosources, wave-guiding

International audienceOne-dimensional polymer-based nano-structures such as nanowires (NWs) and nanotubes (NTs) are nowadays intensively investigated since they promote enhanced properties, as well as new paradigms for electronic, optical, optoelectronic, and photonic devices. Here, we propose a review of recent developments achieved in our group with collaborations on polymer based nanowires and nanotubes. Various polymer based NWs and NTs were synthesized by template strategies with advanced architectures designed for improving their functionality (waveguiding, color control of photoluminescence, photoconductivity and mechanical reinforcement,…). Both conjugated polymers (CPs) and photoresists containing photo-active species (transition metal compound clusters, single-walled-carbon nanotubes SWCNTs) were involved. The focus is made on the emerging strategies for understanding and controlling the behavior of charges, excitons and photons, as well as light propagation in sub-wavelength nanostructures

Octahedral molybdenum cluster as a photoactive antimicrobial additive to a fluoroplastic

Finding methods that fight bacterial infection or contamination, while minimising our reliance on antibiotics is one of the most pressing needs of this century. Although the utilisation of UV-C light and strong oxidising agents, such as bleach, are still efficacious methods for eliminating bacterial surface contamination, both methods present severe health and/or environmental hazards. Materials with intrinsic photodynamic activity (i.e. a material's ability upon photoexcitation to convert molecular oxygen into reactive oxygen species such as singlet oxygen), which work with light within the visible photomagnetic spectrum could offer a significantly safer alternative. Here we present a new, bespoke molybdenum cluster (Bu4N)2[Mo6I8(n-C7F15COO)6], which is both efficient in the generation of singlet oxygen upon photoirradiation and compatible with the fluoropolymer (F23-L) known for its good oxygen permeability. Thus, (Bu4N)2[Mo6I8(n-C7F15COO)6]/F23-L mixtures have been solution-processed to give homogenous films of smooth and fibrous morphologies and which displayed high photoinduced antibacterial activity against four common pathogens under visible light irradiation. These materials thus have potential in applications ranging from antibacterial coatings to filtration membranes and air conditioners to prevent spread of bacterial infections

Improvement of n-type OTFT electrical stability by gold electrode modification

International audienceN-type organic thin film transistors (OTFT) containing modified gold electrodes have been fabricated to investigate the influence of the self assembled monolayer on the transistor characteristics. We report on the effect of drain/source modification by thiol derivatives on the performances, electrical parameters uniformity and electrical stability of C60 transistors. In the literature, electrical instability is often attributed to organic semiconductor (OSC), OSC-insulator interface and insulator. We found here that OSC-metal interfaces affect dramatically the operational stability for bottom gate/bottom contact structure. These effects have been attributed to morphological evolution at the interface metal-OSC induced by the self-assembled monolayers. © 2016 Elsevier B.V

PLGA nanoparticles embedding molybdenum cluster salts: Influence of chemical composition on physico-chemical properties, encapsulation efficiencies, colloidal stabilities and in vitro release

International audienceWe present a screening of poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles embedding a series of inorganic molybdenum octahedral clusters intended for photodynamic therapy (PDT) of cancer. Three cluster compounds from 2 cluster units, [{Mo6Br8}Br6]2− and [{Mo6I8}(OOC2F5)6]2− were studied. [{Mo6Br8}Br6]2−cluster units are found in the soluble ternary salt Cs2[{Mo6Br8}Br6] (CMB) prepared by solid state chemistry at high temperature. In solution Cs+ cations are replaced by tetrabutyl ammonium cations (C4H9)4N+) to form the salt ((C4H9)4N)2[{Mo6Br8}Br6] (TBA2). [{Mo6I8}(OOC2F5)6]2− was prepared combining solid state and solution chemistries; it is paired with Cs+ cations to form Cs2[{Mo6I8}(OOC2F5)6] (CMIF). All tested cluster-based salts could efficiently be incorporated in PLGA nanoparticles as seen with encapsulation efficiencies always higher than 60%. Cluster loaded nanoparticles (CNPs) freshly prepared by solvent displacement method showed spherical shapes, zeta potential values between −20 and −47 mV, polydispersity index in the range 0.123–0.167 and sizes in the range 75–150 nm according to the cluster compound and the polymer-to-cluster mass ratio (P/C), suggesting a good cellular uptake. CNPs colloidal stability was maintened for 3 months when they were stored refrigerated and protected from light but the chemical stability was shorter, i.e. 4 weeks, 1 week and 1 day for CMIF, TBA2 and CMB, respectively, CMIF penta-fluoropropionate apical ligands being less rapidly substituted by hydroxyles groups than TBA2 and CMB halogen apical ligands. FT-IR analysis revealed the lack of strong chemical interaction between cluster compounds and polymer within the nanoparticles. An interesting quick cluster in vitro release driven by diffusion outside the nanoparticles porous matrix was observed for all cluster compounds when P/C ratio was ≤2.5 and only a higher P/C ratio not studied in this work (i.e. >5) could significantly affect the release of the encapsulated cluster compound. Photophysical properties of cluster compounds were preserved following PLGA incorporation. This work presents PLGA nanoparticles as a stable and efficient cluster compound delivery systems for further in vitro and vivo evaluations in cancer models