Nouveau challenge dans la conception d architecture moléculaire pour l optique non-linéaire (ONL)

La conception de molécules pour l optique non linéaires (ONL) est devenue un centre de recherche de pointe pour les télécommunications, les technologies de l'information et le stockage de données optiques. Les molécules dipolaires substituées par des groupes donneur-accepteur ont été les chromophores les plus étudiés pour l ONL. Cependant les molécules dipolaires diverses limitations telles que leur transparence optique, leur faible stabilité thermique et leur tendance à adopter un alignement antiparallèle à l'état solide. Récemment, une nouvelle classe de matériaux est apparue basé sur des symétries octupolaire qui ne possède pas de dipôle permanent, pour les applications ONL. Au niveau structural, la structure générique idéale pour des molécules tridimensionnelles avec une distribution de charges octupolaire est un cube avec des charges opposées alternées à chaque angle. À ce jour, aucune molécule représentant le cube vrai (déformé) avec huit charges alternées aux sommets et délocalisation des charges complètes entre les plans supérieurs et inférieurs n a été décrite. Dans le cadre de cette thèse, des complexes de lanthanides III à partir de phthalocyanines de type ABAB présentant en alternance des groupes donneurs et accepteurs d'électrons ont été synthétisés représentant le premier réel octupole. Ces structures ont été caractérisé par UV-NIR, X-Ray et présentent les plus élevés hyperpolarisabilité quadratique jamais enregistré pour des molécules octupolaires. En outre, ce travail a été étendu à divers type de double-decker de lanthanides homoleptiques non-octupolaire basé sur des phthalocyanines AB3, A4, B4, T4. Il a été observé que ces complexes présentent aussi des mesures d hyperpolarisabilité quadratique élevés, mais inferieur a celles trouvé pour la série de complexes Ln (ABAB)2 octupolaire, comme prévu.The design of nonlinear optical (NLO) molecules has become a focus of current research in telecommunications, information technologies and optical data storage. Donor-acceptor substituted dipolar molecules have been the most investigated NLO chromophores. Dipolar molecules, however, have several limitations such as low optical transparency, low thermal stability and their strong tendency to adopt anti-parallel packing in the solid state. Recently, a new class of materials based on octupolar symmetries, which lack permanent dipole moments, has been proposed for NLO applications. At a structural level, it can be shown that the basic template for 3D octupolar molecules comes to a cube with alternating charges at the corners such as donor and acceptor substituent. Despite all the various structures reported, it is worth noting that no molecules actually representing the real octupolar cube have been obtained so far. In this thesis, we showed that the real octupolar cube can be demonstrated by lanthanide III complexes based on ABAB type phthalocyanine featuring alternating electron donor and electron acceptor groups. These structures are characterized by UV-NIR, X-Ray and exhibit highest quadratic hyperpolarizability ever reported for an octupolar molecule. Moreover, this work was extended to nonoctupolar lanthanide homoleptic double-decker complexes based on AB3, A4, B4, T4 type phthalocyanines. It was observed that these molecules present a quite large quadratic hyperpolarizability too, but smaller than the one obtained for the Ln(ABAB)2 series, as expected.LYON-ENS Sciences (693872304) / SudocSudocFranceF

Anthracene dopping effects on thin films properties of octakis(alkylthio) substituted lutetium bisphthalocyanine

In this work, the investigation of structural features, spectral and electrical properties of spin-coated films of substituted lutetium bisphthalocyanine Lu ( Pc ( SR )8)2, where R = - C 6 H 13 was carried out. The current-voltage characteristics of ITO/ Lu ( Pc ( SR )8)2/ Al film sandwich structures were measured over the temperature range 120–380 K. AC electrical properties, mainly the dependence of conductance and capacitance on frequency and temperature are also discussed. Structural and electrical properties of anthracene-doped Lu ( Pc ( SR )8)2, films have also been investigated. Furthermore, optical properties of thin films of pure and anthracene-doped Lu ( Pc ( SR )8)2 films were also studied using spectroscopic ellipsometry, while atomic force microscopy (AFM) was used to study changes in films' morphology of doped films and compared with that of undoped films. Doping Lu ( Pc ( SR )8)2, films with anthracene is shown to lead to an increase in films' conductivity. These studies will provide full understanding of the physical properties of the Lu ( Pc ( SR )8)2, thin films, both doped and undoped, with the aim of exploitation in electronic device applications, such as fabrication of all organic solar cells. </jats:p

Orientation of the liquid crystalline nickel phthalocyanine films confined between electrodes

In this paper, the orientation of thin films of tetra-substituted nickelphthalocyanine NiPcR4 (R = –SCH[CH2(OCH2CH2)2OC2H5]2) deposited between two electrodes is studied by the method of polarized Raman spectroscopy and polarized microscopy. It has been shown that the films of NiPcR4confined between ITO and metal (Al, Au) electrodes are characterized by homeotropic alignment while no homeotropic alignment was observed on ITO substrate with air interface. These findings are very important for the interpretation of electrical conduction through thin films of NiPcR4 in sandwich structures