2,5-Thiophene Substituted Spirobisiloles - Synthesis, Characterization, Electrochemical Properties and Performance in Bulk Heterojunction Solar Cells

International audienceNew spirobisilole molecules containing thienyl (DTSBS) and bis-thienyl (BBTSBS) electron donor groups have been synthesized for use as the donor material in bulk-heterojunction solar cells together with PCBM. The spectroscopic, electrochemical and thermal properties of DTSBS and BBTSBS have been investigated. All these new spirobisiloles exhibit excellent thermal stability. Cyclic voltammetry measurements revealed reversible and irreversible oxidation and irreversible reduction processes. The highest occupied and lowest unoccupied molecular orbital (HOMO/LUMO) energy levels were determined from electrochemical measurements and DFT calculations. The HOMO/LUMO energy levels were estimated to lie in the range -5.2 to -2.3 eV for DTSBS and -4.9 to -2.6 eV for BBTSBS. For both compounds, electropolymerization processes occur at potentials higher than 1.5 V leading to low band gap electrogenerated polymers. Spin-coating-deposited bulk-heterojunction solar cells fabricated with the novel spirobisiloles as donor and PCBM as acceptor displayed open-circuit voltages up to 0.4 V, short-circuit currents around 0.5 mA.cm-2, and power conversion efficiencies approaching 0.1 %

Conception, synthèse et caractérisation de systèmes p-conjugués organosiliciés pour l'élaboration des dispositifs optoélectroniques.

Ce travail porte sur la conception de nouveaux composés p-conjugués, potentiellement utilisable en électronique organique en tant que matériaux actifs dans des dispositifs tels que les OLEDs, les cellules photovoltaïques et les capteurs optiques. Dans ce but, nous avons exploité le motif silacyclopentadiène appelé également silole, possédant un bon rendement quantique de fluorescence à l'état solide et une excellente conduction des électrons. Dans un premier temps, l'introduction de groupements structurants (triptycène, stilbènes..) sur le silacyclopentadiène a permis de moduler l'arrangement moléculaire dans la couche active et par conséquent, les propriétés d'électroluminescence. Des diodes possédant des performances très encourageantes furent ainsi obtenues. Dans un deuxième temps, des dérivés siloles présentant une structure tridimensionnelle et une architecture spirosilole (accepteur)-bithiophène (donneur) furent synthétisées. Une cellule photovoltaïque basée sur ces édifices présentant des performances encourageantes fut ensuite mis au point. Enfin, l'étude des mécanismes de transfert d'énergie entre un film de polymère fonctionnalisé par un groupement sensible silole et des composés nitroaromatiques nous a permis de réaliser un nouveau type de capteur optique hautement sensible pour la détection d'explosifs.This work concerns the design of new p-conjugated compounds, potentially useful in organic electronics as active materials in devices such as OLEDs, photovoltaic cells and optical sensors. To this end, silacyclopentadiene, alias silole, groups were used exhibiting high fluorescence quantum yields in the solid state and excellent electron conductivities. Firstly, the introduction of structurizing groups (triptycene, stilbenes etc.) at the silacyclopentadiene allowed tuning of the molecular arrangement in the active layer and, consequently, the electroluminescence properties. Diodes showing very encouraging activities were thus obtained. Secondly, silole derivatives possessing a three-dimensional structure and a spirosilole (acceptor) - bithiophene (donor) architecture were synthesized. A photovoltaic cell based on these molecules was then developed exhibiting encouraging activity. Finally, a study of the mechanisms of energy transfer between a polymer film functionalized by a sensitive silole group and nitroaromatic compounds enabled the development of a new type of highly sensitive optical sensor for the detection of explosives.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Erratum: Quasicontinuous Atom Laser in the Presence of Gravity [ Phys. Rev. Lett. 86, 4729 (2001)]

International audienceIn a recent Letter [1], we analyzed theoretically the extraction of a quasicontinuous atom laser out of a trappedBose-Einstein condensate. The explicit expression for the outcoupling rate given in this Letter was underestimated by afactor of 2, and the correct expression should read (using the notation of [1])

Bis(hexafluoroacetylacetonato)manganese(II) complex of 1,1-dimethyl-2,5-bis-(3-N-tert-butyl-N-phenylaminoxyl) -3,4-diphenylsilolacyclopentadiene.

Crystals of the 1st bis-adduct of 2,5-bis[3-(tert-butylaminoxyl)phenyl]-1,1-dimethyl-3,4-diphenylsilole with bis(hexafluoroacetylacetonato)manganese(II) are monoclinic, space group P21/n; Z = 2. The Mn atom lies on a crystallog. inversion center and is bound to two chelating hexafluoroacetylacetonate ligands and two monodentate nitroxide groups in a distorted octahedral configuration. The silole ligands present a propeller-like arrangement of the benzene rings around the Si-contg. five-membered ring. The dihedral angles between the complexed nitroxides and the benzene rings to which they are bound are smaller than those found in the free ligand

Synthesis and characterization of a new organometallic magnetic coupler based on the silole ring

The synthesis, x-ray structure, and magnetic properties of a new aminoxyl biradical linked by a silacyclopentadienyl ring is reported..