Radiation-induced polymerization of 3-hexylthiophene in oxygen-free and oxygen-saturated dichloromethane solvent

We thank Jean-Michel Guigner (IMPMC, Université Pierre et Marie Curie, France) for Cryo-TEM experiments.As alternative radiolytic approach, the synthesis of P3HT was made possible thanks to the oxidation of 3HT monomers by chloromethyl and dichloromethyl radicals or by their corresponding peroxyl radicals in situ produced by dichloromethane solvent radiolysis. Under two different experimental conditions, in oxygen-free solution and in oxygen-saturated solution, two different polymers, “P3HTN2” and “P3HTO2” respectively, were successfully synthesized. Both produced materials were discerned by several analytical and spectroscopic techniques. UV–Vis absorption spectroscopy results showed that the radiolytic yield of 3HT oxidation in dichloromethane solvent is higher under O2 atmosphere. Indeed, a dose of 75 kGy was needed to polymerize 10 mM in 3HT under N2 atmosphere, meanwhile a dose of 35 kGy was sufficient to polymerize the same amount of 3HT under O2. The average molecular weight of P3HTO2was found higher than that of P3HTN2 as revealed by SEC chromatography analysis. Also, P3HTO2exhibits better thermal stability than P3HTN2. ATR-FTIR spectroscopy revealed the specific presence into P3HTO2 polymers of some functional groups such as carbonyl, hydroxyl and carboxyl moieties, which clearly explains the difference between the morphological structures of P3HTN2 and P3HTO2 as highlighted by cryo-TEM, SEM and AFM microscopies. Finally, both radio-synthesized P3HTN2 and P3HTO2 polymers were found characterized by remarkably significant conductive, electronic and optical properties

Radiation-induced reduction-polymerization route for the synthesis of PEDOT conducting polymers

Synthesis of conducting poly(3,4-ethylenedioxythiophene), PEDOT, is achieved through an original reduction-polymerization route: γ-radiolysis of aqueous solutions containing EDOT monomers under N2 atmosphere. According to UV-vis absorption spectrophotometry and ATR-FTIR spectroscopy, reduction of EDOT is initiated by hydrated electrons produced by water radiolysis and leads to PEDOT polymers through coupling reactions. The morphology of PEDOT is characterized by Cryo- TEM microscopy in aqueous solution and by SEM after deposition. In an original way, high resolution AFM microscopy, coupled with infrared nanospectroscopy, is used to probe the local chemical composition of PEDOT nanostructures. The results demonstrate that spherical self-assembled PEDOT nanostructures are formed. TGA analysis and four point probe measurements demonstrate that thermal stability and electrical conductivity of PEDOT polymers obtained by the present original reduction-polymerization method are close to those of PEDOT we previously prepared by radiolysis according to an oxidation-polymerization route

Conjugated Polymer Nanostructures for Energy Conversion and Storage Applications

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Elaboration de molécules pi-conjuguées à base de triphénylamine pour la réalisation de dispositifs photovoltaïques hybrides sensibilisés.

Les cellules photovoltaïques hybrides sensibilisées tout solide (ssDSSC) sont considéréescomme une technologie émergente dans le domaine de l'énergie solaire afin de remplacer les cellules solaires classiques basées sur le silicium ou même celles utilisant un électrolyte liquide(DSSC). Dans ce but, nous nous sommes intéressés à l'élaboration de molécules p-conjuguées (verresmoléculaires) de type p pour une application dans les ssDSSCs.Le premier axe de cette étude a consisté à synthétiser deux familles de molécules à base detriphénylamine/thiéno[3,2-b]thiophène/ thiophène (avec et sans chaîne nonyle pour déterminerl'effet de la solubilité). Ces composés ont été obtenus par des couplages de Stille ou Suzuki avec des rendements globaux variant entre 11% et 37% (pour six à dix étapes).Dans le but de déterminer les propriétés physico-chimiques des composés obtenus, lesecond axe a été consacré aux caractérisations thermiques, optiques et électroniques des moléculessynthétisées. Les mesures thermiques par analyse thermogravimétrique (ATG) ont montré unestabilité des composés supérieure à 340C. En outre, l'analyse thermique différentielle (DSC) apermis de déterminer la température de transition vitreuse (Tg), la plus élevée atteignant 57C. Lesgaps optique et électronique ont été déterminés par absorption UV-Visible (entre 2,87eV à 2,41eV enfilm) ou voltampérométrie cyclique (entre 3,26eV à 2,60eV). Les niveaux énergétiques de la HOMO etLUMO ont également été déterminés par voltampérométrie cyclique. Ils ont montré des niveauxadéquats surtout pour celui de la HOMO (compris entre la HOMO du colorant et celle de la cathode)pour une application photovoltaïque. Enfin, les mesures de mobilité de trous ont mis en évidence desrésultats encourageants et prometteurs variant entre 10-3 cm2.V-1.s-1 et 1 cm2.V-1.s-1.Le troisième axe est consacré à l'étude théorique de ces molécules à l'aide de la modélisationmoléculaire. Les tendances obtenues pour les niveaux énergétiques (HOMO et LUMO), les gaps optiques, l'énergie de réorganisation interne (donnant une idée de la mobilité théorique de charges)recoupent assez bien les données expérimentales.Finalement, le dernier axe porte sur la détermination des performances photovoltaïques de ces composés. Pour l'un d'eux une efficacité de 0,5% a été obtenue sans optimisation et de manièredurable puisque cette efficacité reste inchangée après une année. Le taux de remplissage de cecomposé dans TiO2 atteint de 62 à 83%.Mots clés : Dispositifs photovoltaïques hybrides tout solide ssDSSC, triphénylamine, thiéno[3,2-b]thiophène, thiophène, verre moléculaire, modélisation moléculaire, taux de remplissage.Solid state dye-sensitized solar cells (ssDSSC) are considered as an emerging technology in order to replace conventional silicon solar cells or even those using liquid electrolyte. In order to improve the performance of ssDSSC devices, we were interested by the development of star-shaped molecules derived from thieno[3,2-b]thiophene unit and triphenylamine core.Two series of new substituted triphenylamine (TPA) derivatives with thiophene and thieno[3,2-b]thiophene units (with and without nonyl group C9H19) were synthesized in a combinatorial manner. These compounds were obtained by Stille or Suzuki coupling with a yield between 11% and 37% (from six to ten steps).In order to determine the properties of these compounds, thermal, optical and electrochemical characterizations were carried out. The measurements by thermogravimetric analysis (TGA) showed a high stability of the compounds above 340C. Differential thermal analysis (DSC) was used to determine the glass transition temperature (Tg) where the highest reaching 57C. The optical and electronic gaps were determined by UV-Visible absorption ( we found from 2.87 eV to 2.41 eV in film) or cyclic voltammetry (we found from 3.26 eV to 2.60 eV). The energy levels of HOMO and LUMO were also determined by cyclic voltammetry. They showed adequate levels especially for HOMO levels (ideally HOMO between the dye and that of the cathode) for a photovoltaic application. Finally, hole mobility have shown encouraging results and promising ranging from 10-3 cm2.V-1.s-1 and 1 cm2.V-1.s-1.The theoretical study of these molecules was also carried out using molecular modeling as B3LYP. The energy levels (HOMO and LUMO), the optical gaps, and the energy of internal reorganization (giving an idea of the theoretical charges mobility) have the seam trend overlap the experimental data.The photovoltaic performance of these compounds was performed. An efficiency of 0.5% (not optimized results) has been obtained for the best of them. This efficiency was sustainable after one year. The pore filling ratio of this compound in TiO2 reached from 62 to 83%.Keywords : Solid state dye-sensitized solar cells (ssDSSC), triphenylamine, thieno[3,2-b]thiophene, thiophene, molecular glasses, theoretical calculations, pore filling.CERGY PONTOISE-Bib. electronique (951279901) / SudocSudocFranceF

Truxene: a promising scaffold for future materials

International audienceTruxene (10,15-dihydro-5H-diindeno[1,2-a;1′,2′-c]fluorene), which is a heptacyclic polyarene structure, has attracted a great deal of interest due to its exceptional solubility, high thermal stability and ease with which it may be modified. Over the years and thanks to the advances in the synthesis of truxene derivatives, the scope of applications of this attractive building block, initially limited to synthesis and photoluminescence, has nowadays been extended to organic electronics. This review aims at highlighting the benefits brought by the introduction of this rigid star-shaped molecule in different materials. Perspectives for this highly appealing molecule in future research will also be put forth

Triphenylamines and 1,3,4-oxadiazoles: a versatile combination for controlling the charge balance in organic electronics

International audienceDuring the past decade, organic electronics has attracted a great deal of interest due to its applicability in a wide range of applications and high potential for commercial success. These applications notably range from organic light emitting diodes (OLEDs) to organic photovoltaics (OPVs) and sensors. Organic diodes undoubtedly have the potential to redefine many present day lighting solutions if performances and device stability are significantly improved. In these different applications, materials which combine in one molecule a balanced hole and electron transport are currently under intensive research as these materials can ensure an effective exciton recombination or dissociation within the active layer. Over the years, several basic structures have received the attention of researchers for the design of these appealing materials, namely triphenylamines (TPA) and oxadiazoles (OXD) that can respectively act as the hole-transporting and electron-transporting moieties in these ambipolar materials. This review aims at reporting the different OXD-TPA hybrids that have been synthesized to date and to develop a systematic understanding of the structure-property-performance relationship

Recent advances in small molecular, non-polymeric organic hole transporting materials for solid-state DSSC

Issue from thin-film technologies, dye-sensitized solar cells have become one of the most promising technologies in the field of renewable energies. Their success is not only due to their low weight, the possibility of making large flexible surfaces, but also to their photovoltaic efficiency which are found to be more and more significant (>12% with a liquid electrolyte, >7% with a solid organic hole conductor). This short review highlights recent advances in the characteristics and use of low-molecular-weight glass-forming organic materials as hole transporters in all solid-state dye-sensitized solar cells. These materials must feature specific physical and chemical properties that will ensure both the operation of a photovoltaic cell and the easy implementation. This review is an english extended version based on our recent article published in Matériaux & Techniques 101, 102 (2013)

Recent advances in small molecular, non-polymeric organic hole transporting materials for solid-state DSSC

Issue from thin-film technologies, dye-sensitized solar cells have become one of the most promising technologies in the field of renewable energies. Their success is not only due to their low weight, the possibility of making large flexible surfaces, but also to their photovoltaic efficiency which are found to be more and more significant (>12% with a liquid electrolyte, >7% with a solid organic hole conductor). This short review highlights recent advances in the characteristics and use of low-molecular-weight glass-forming organic materials as hole transporters in all solid-state dye-sensitized solar cells. These materials must feature specific physical and chemical properties that will ensure both the operation of a photovoltaic cell and the easy implementation. This review is an english extended version based on our recent article published in Matériaux & Techniques 101, 102 (2013)

Bioconjugaison de la fibronectine à des sondes exogènes (du fluorophore organique à la nanoparticule hybride)

La fibronectine (Fn) est une protéine structurante de la matrice extracellulaire (MEC) et est impliquée dans de nombreux comportements cellulaires. Le suivi du devenir d une protéine de la MEC telle que la Fn n est possible que par l intermédiaire de sondes détectables par imagerie. L objectif de ce travail de thèse est de conjuguer la Fn à différentes sondes exogènes : un fluorophore organique et deux types de nanoparticules hybrides. L étude ce concentre sur l impact de la bioconjugaison sur la structure et les fonctionnalités biologiques de la Fn. L ensemble de ce travail met en évidence l importance du contrôle des conditions de bioconjugaison (stœchiométrie de greffage, pH, solvant). L obtention d un complexe Fn-FITC fonctionnel rend possible le suivi au cours du temps du remodelage de la Fn simultanément à la migration cellulaire. L élaboration d un complexe Fn/nanoparticule de conformation globale correcte met en évidence des interactions spécifiques Fn/ cellules.Fibronectin (Fn) is a structural protein of extracellular matrix (ECM) and is implicated into many cellular behavior (adhesion, migration ). Follow the becoming of an ECM protein as Fn is possible only via imaging dyes. The aim of this PhD work is to conjugate Fn to different exogenic dyes : organic fluorophore (and two sorts of double detection hybrid nanoparticles. The study focuses on bioconjugation impact onto Fn structure and biological functionalities. This work put in evidence the importance of controlling bioconjugation conditions particularly bioconjugation stœchiometry, pH value and solvent condition. Getting functional Fn-FITC complex make possible the following of Fn matrix remodeling simultaneously of cellular migration. The Fn/nanoparticles conjugate presents a correct global conformation and specific interaction with cells.CERGY PONTOISE-BU Saint-Martin (951272103) / SudocSudocFranceF

Impact of Organic Hole Transporting Material and Doping on the Electrical Response of Perovskite Solar Cells

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