Yes / A continuous, scalable, and solvent‐free method for the synthesis of various naphthalic imides and perylene diimides (PDIs) using twin‐screw extrusion (TSE) is reported. Using TSE, naphthalic imides were obtained quantitatively without the need for excess amine reactant or product purification. With good functional‐group tolerance, alkyl and benzyl amine derived PDIs (incl. commercial dyes) were obtained in 50–99 % yield. Use of K2CO3, enabled synthesis of more difficult aniline‐derived PDIs. Furthermore, an automated continuous TSE process for Pigments Black 31 and 32 is demonstrated, with a throughput rate of about 1500 g day−1, corresponding to a space time yield of about 30×103 kg m−3 day−1, which is 1–2 orders of magnitude greater than for solvent‐based batch methods. These methods provide substantial waste reductions and improved efficiency compared to conventional solvent‐based methods. / Engineering and Physical Sciences Research Council. Grant Numbers: EP/L019655/1, IAA1718-04-1117

Interfacial charge transfer between metal oxides and organic semiconductors has been found to limit the efficiency of organic optoelectronic devices. Although a number of investigations of inorganic/organic systems exist, very few generally applicable rules for oxide/organic interfaces have been developed and many questions about these systems remain unanswered. Thus the studies presented in this dissertation were designed to improve the understanding of the fundamental interface physics of metal oxide/organic systems. Single molecule fluorescence microscopy was employed to determine the charge transfer mechanism while photoelectron spectroscopy was used to determine the energy level alignment of model systems. Additional computational studies allowed the examination of the properties of the charged organic molecules involved in charge transfer and modeling of the molecule-surface interaction. Calculations of the ground state properties and excited state transitions of the neutral and singly charged states of a modified perylene molecule were performed to provide insight into the orbitals of the initial and final states involved in the interfacial charge transfer process. The design and implementation of a novel UHV single molecule microscope is described. This microscope was used to observe the excited state charge transfer between a modified perylene molecule and Al₂O₃ (0001). The charge transfer mechanism was identified as involving activated trapping and detrapping of the defect derived states within the Al₂O₃ band gap, which resulted in the observation of strongly distributed kinetics for this system. The influence of defects and adsorbates on the electronic structure of ZnO and its interface with organic semiconductors was determined from photoelectron spectroscopy. Modified perylene molecules were found to have strong chemisorptive interactions with the ZnO surface involving charge transfer from defect derived ZnO states to the LUMO, while magnesium phthalocyanine molecules appear to have only weak physisorptive interactions with the ZnO surface. The interfacial investigations of the organic/oxide systems demonstrate the rich defect structure present in metal oxides. In both cases, defects were found to control the interfacial interactions between the metal oxide surface and the modified perylene molecules. Thus the manipulation of these defects states is of fundamental importance for optoelectronic device design.

Recent advances in the self-assembly of highly organized structures of organic semiconducting molecules by controlled non-covalent interactions has opened avenues for creating materials with unique optical and electrical properties. The main focus of this thesis lies in the synthesis and self-assembly of n-type perylene based organic semiconducting molecules into highly organized materials. Perylene based molecules used in this study are perylene diimide (PTCDI, two side-chains), perylene mono imide (m-PTCI, one side-chain), perylene tetracarboxylic acid (PTCA, no side-chain) and tetra-alkali metal salts of PTCA (M 4 -PTCA, no side-chain), which are synthesized from the parent perylene tetracarboxylic dianhydride (PTCDA). The self-assembly of these molecules have been performed using solution processing methods (dispersion, phase-transfer, and phase-transfer at high temperature) by taking advantage of the changes in solubility of the molecules, wherein the molecular interactions are maximized to favorably allow for the formation of highly organized structures. Dimension control (1D, 2D and 3D structures) of self-assembly has been obtained for different perylene based molecules by appropriate design of the molecule followed by controlling the conditions of assembly. In case of PTCDI, a new solution processing method phase-transfer at high temperature (2L-HT) allowed for the controlled formation of extremely long and fluorescent 1D structure. For the m-PTCI molecules the organization by the 2L-HT method was found to result in highly organized, single-crystalline, fluorescent 2D sheets. In the case of perylene based molecules with no side-chains two different methods have been developed for the realization of organized 1D nanostructures. The first method utilizes the chemical conversion of a highly soluble PTCA into 1D nanofibers of the parent insoluble perylene tetracarboxylic anhydride. The second method utilizes the assembly of tetra potassium salt of PTCA (K 4 -PTCA) into 1D nanostructures. Furthermore, it has been demonstrated that these 1D nanostructures can be chemically converted to two different chemical species, both of which still retain the 1D morphological characteristic, though with changes in the size. Various functional self-assembled structures developed in this thesis opens up new avenues to explore structure-property-function relationships and their use in applications such as sensors, electronics and opto-electronic devices.

Perylene-based materials, including charge-transport discotic liquid crystals and charge-transfer long-wavelength absorbing chromophores, for potential organic electronic and optoelectronic applications, were designed, synthesized and characterized. Two types of discotic liquid crystals, perylene diimides and coronene diimides, can form columnar liquid crystalline phases over a wide temperature range; many of them can have room-temperature liquid crystalline phases after cooling from isotropic liquid. Their charge transport properties were studied by space-charge limited current method; high charge carrier mobilities, with the highest being up to 6.6 cm2/Vs, were found in liquid crystalline phases of these materials under ambient conditions. Structural variables, including aromatic cores and side groups, were examined to get a certain degree of understanding of charge transport properties in these discotic liquid crystals. It was found that mesophase order can have an important effect on charge carrier mobilities. The discotic liquid crystals with high charge carrier mobilities are serious candidates for use in large-area low-cost applications such as solar cells. Long-wavelength, highly absorbing chromophores, featuring donor-substituted perylene diimides, were generated by a combination of charge-transfer process and conjugation extension. The charge-transfer chromophores are expected to lead to further investigation on their potentials as sensitizers in Grtzel solar cells.

Low density surface sites are believed to play an important role in processes occurring on oxide surfaces, including catalysis and particle and film nucleation. However, our understanding of the role and chemical nature of such sites play in these processes is limited by the inability to experimentally detect minority surface sites in many oxide systems. The research performed for this dissertation is focused on developing a surface science technique utilizing fluorescent molecules to titrate specific surface sites on planar fused silica surfaces in an ultra-high vacuum (UHV) environment. High sensitivity (low detection limit) is achieved by using derivatives of perylene, a high quantum yield fluorophore. High specificity is attained by employing perylene derivatives with functional groups designed to react chemically with and titrate various sites. In addition to titrating the well-studied hydroxyl sites with perylene-3-methanol (density ~ 10¹⁴ cm⁻²), which is used to establish the technique, the detection of strained siloxane sites (~ 10¹² cm⁻²), ) with perylene-3-methanamine and oxygen vacancy sites (~ 10¹¹ cm⁻²), ) with 3-vinyl perylene is demonstrated. Particle nucleation on oxides is suspected to involve defects that trap adatoms and form critical nuclei. Using this technique, the possible role strained siloxane and oxygen vacancy sites play in trapping adatoms during the nucleation of Ge nanoparticles on silica surfaces is examined. / text

Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-29Bitstream added on 2014-06-13T18:55:41Z : No. of bitstreams: 1 volpati_d_me_bauru.pdf: 5747357 bytes, checksum: 51588cae60e48257109b7cd67deb6faa (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Filmes finos do bis benzimidazo perileno (AzoPTCD) foram fabricados usando as técnicas de Langmuir, Langmuir-Blodgett (LB) e evaporação a vácuo (PVD). A estabilidade térmica durante a fabricação dos filmes PVD ('DA ORDEM DE' '400 GRAUS' a '10 POT. -6' Torr) e a integridade da estrutura molecular pela dissolução do AzoPTCD em ácidos fortes para a fabricação dos filmes de Langmuir e LB foram monitoradas pelo espalhamento Raman. Complementarmente a análise termogravimétrica revelou que a degradação térmica do AzoPTCD ocorre a '675 GRAUS'. Os filmes de Langmuir revelaram um alto empacotamento molecular do AzoPTCD sobre a subfase aquosa, onde as moléculas estão apoiadas sobre seu eixo maior ou menor. A adição de íons metálicos na subface aquosa revelou uma sensibilidade do AzoPTCD a presença destes íons, deslocando as isotermas para maiores valores de área molecular média. O crescimento dos filmes LB e PVD sobre substratos sólidos foi monitorado através da espectroscopia de absorção UV-Vis, e a morfologia dos filmes PVD foi estudada via microscopia de força atômica (AFM) em função da espessura em massa. A organização molecular dos filmes PVD foi determinada usando as regras de seleção de superfície aplicadas na espectroscopia de absorção no infravermelho (modos de transmissão e reflexão). Apesar da organização molecular, a difração de raios-x revelou que os filmes PVD são amorfos. Cálculos teóricos (Density functional theory -B3LYP) foram usados para atribuição dos modos vibracionais nos espectros de absorção no infravermelho e espalhamento Raman ressoante Nanoestruturas metálicas, capazes de ativar os fenômenos de amplificação em superfície foram usadas para estudos de espalhamento Raman ressonante amplificado em superfície (SERRS) e fluorescência amplificada em superfície (SEF) nos filmes LB e PVD. Através... / Thin solid films of bis benzimidazo perylene (AzoPTCD) were fabricated using Langmuir, Langmuir-Blodgett (LB) and physical vapor deposition (PVD) techniques. Thermal stability during the fabrication of PVD films ('DA ORDEM DE' '400 GRAUS' a '10 POT. -6' Torr) and chemical structure integrity by dissolution of the AzoPTCD in a strong acid were monitored by Raman scattering. Complementary thermogravimetric results showed that thermal degradation of AzoPTCD occurs at '675 GRAUS'. Langmuir films showed a high molecular packing with the molecules tilted onto the aqueous subphase. Besides, the AzoPTCD л-A isotherms were shifted to larger areas due to the addition of metallic ions in the subphase. The growth of the LB and PVD films were established through UV-Vis absorption spectroscopy, and the surface morphology in PVD films was probed by atomic force microscopy (AFM) as function of the mass thickness. The AzoPTCD molecular organization in the PVD films was determined using the selection rules of infrared absorption spectroscopy (transmission and reflection-absorption modes). Despite the molecular organization, X-ray diffraction revealed that the PVD films are amorphous. Theoretical calculations (Density Functional Theory, B3LYP) were used to assign the vibrational modes in the infrared and Raman spectra. Metallic nanostructures, able to sustain localized surface plasmons (LSP) were used to achieve surface-enhanced resonance Raman scattering (SERRS) and surface-enhanced fluirescence (SEF) in the LB and PVD films. The conductivity and rectifier character of the PVD films of AzoPTCD were determined by current as function of tension curves (I(V)) in dc measurements. The impedance spectroscopy in ac measurements was used to study the performance of PVD films of the AzoPTCD as transductor elements in sensing units applied to discriminate... (Complete abstract click electronic access below)

Ce travail de thèse porte sur l'étude de dérivés du pérylène-3,4:9,10-tétracarboxylique acide diimide comme semi-conducteurs pour l'électronique organique, et plus particulièrement pour la réalisation de transistors organiques à effet de champs. Les objectifs de ce travail sont la synthèse de dérivés du pérylène à l'aide entre autres de réactions d'halogénation ou de couplage de Suzuki-Miyaura, et la fabrication de transistors organiques à effet de champs. Dans un premier temps, une large gamme de dérivés du pérylène a été synthétisée et caractérisée. Des études spectroscopiques et électrochimiques ont pu être menées, notamment afin de déterminer les énergies des orbitales frontières de nos molécules. Puis dans un second temps, la réalisation de transistors organiques à effet de champs a été mise en oeuvre, en commençant par un gros travail d'optimisation des conditions de formulation des encres, de dépôt et de traitement du film. Puis ces transistors ont été caractérisés en mesurant les courants drain-source. Mots-clés : semi-conducteur, pérylène, transistor organique à effet de champs, couplage de Suzuki-Miyaura, impression jet d'encre. / This study deals with the synthesis of perylene-3,4:9,10-tetracarboxylic acid bisimide derivatives and their use as semi-conductors for organic electronics, and more specifically for the realization of organic field-effect transistors. The goals of this study are the synthesis of perylene derivatives, using halogenation reactions or Suzuki-Miyaura coupling, and the fabrication of organic field-effect transistors.In the first part of the work, a wide variety of perylene derivatives has been obtained and fully characterized. Spectroscopic and electrochemical studies have been performed to determine energy levels of the frontier orbitals.In the second part, the making of organic field-effect transistors was realized, beginning with the research of optimal conditions for ink formulation, deposition and annealing of the film. Then those devices have been characterized by measuring the source-drain current.Keywords: semi-conductor, perylene, organic field-effect transistor, Suzuki-Miyaura coupling, ink jet printing.

The dissertation thesis deals with study of advanced steady-state and time-resolved fluorescence techniques, which can be used for study of micellar systems properties. Selected fluorescence techniques were used for characterization of Septonex and CTAB cationic micellar systems and theirs interactions with hyaluronan. Fluorescent probe pyrene was used for determination of critical micelle concentration (CMC) and micellar aggregation number of these surfactants. The changes of fluorescence behaviour of fluorescein and prodan were studied in wide concentration range of Septonex. Next chapter of thesis deals with study of Förster resonance energy transfer between perylene and fluorescein in Septonex and CTAB micellar solutions and the effect of hyaluronan addition to these systems. Also steady-state and time-resolved fluorescence anisotropy studies were used for research of the effect of hyaluronan addition to micellar solutions. The last chapter of this thesis is focused on photophysical behaviour of Prodan in different solutions (water, Septonex solutions below CMC, hyaluronan solution, Septonex micellar solution and Septonex micellar solution with hyaluronan), which was discussed on the basis of time-resolved emission spectra.

This diploma thesis is focused on determination of aggregation behavior of selected phospholipids (lecithin; 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine) in water and on the effect of native hyaluronan addition of various molecular weights and concentrations on this behavior. The behavior has been investigated with fluorescence spectroscopy using pyrene and perylene as fluorescence probes being able to penetrate into hydrophobic cavities of formed aggregates. Critical aggregation concentration and the concentration at which lecithin begins to aggregate have been determined. Regarding 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine, it was possible to determine only the beginning of aggregation value. The values of this parameter for lecithin and for 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine correspond in the order. It has been investigated, that the addition of native hyaluronan has only in some systems slight effect on the aggregate behavior of selected phospholipids.

In this diploma thesis were investigated in terms of microviscosity liquid and condensed systems composed of hyaluronan (Hya) and cationic surfactant cetyltrimethylammonium bromide (CTAB). The excitation and emission spectra, lifetime, steady-state fluorescence anisotropy and time-resolved fluorescence anisotropy of the samples were measured. First, was studied the formation of hydrophobic domains in the system Hya-CTAB at concentration of CTAB lower than its critical micelle concentration in an aqueous solution and 0.15M NaCl. It was found that in an aqueous solution small hydrophobic domains linked to chains Hya are formed. Then an increasing concentration of CTAB leads to phase separation and formation of gel. Due to the addition of NaCl then leads to the reorganization of this system and probably the formation of free micelles in the solution. Were also studied condensed phase of system Hya-CTAB-NaCl at high concentrations of surfactant during fourteen days of ageing. It was found that the microviscosity of hydrophobic domains is constant, but the microviscosity of hydrophilic parts gradually decreases.