Studies On Synthesis, Self-assembly And Properties Of Organic Conjugated Molecules

In recent years, nanostructures which show the potential application in material science and biology have attracted more attention. Especially, those based on organic conjugated compounds play a vital role due to the different morphology, adjusting properties and easy preparation. In this thesis, aggregation morphologies of the new synthesized compounds based onÏ€-Ï€stacking, hydrophobic interaction were investigated. Meanwhile, the related properties were also measured in the field of organic nanomaterials and OLEDs. The dissertation consists of 3 parts.1. Four shapes of 9,10–diphenylanthrancene (DPA) nanostructures: microoctahedral, microrod, nanowire and nanosphere have been prepared via surfactant-assisted self-assembly process. The obtained micro/nanostructures were characterized by UV-vis, fluorescence spectra, X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. Organic light-emitting diodes were also fabricated, and the testing results showed that the different shapes of DPA structure do affect the performance of diodes.2. One-dimensional 9,10-dibromoanthracene (DBA) and 9,10-dicyanoanthracene (DCNA) nanowires have been obtained in aqueous solution viaÏ€-Ï€stacking and hydrophobic interaction. In aqueous solution, the obtained nanowires emitted green light instead of blue light for DBA and DCNA in THF solution. Meanwhile, the obvious photocurrent responses were produced from the self-assemble nanowires/rGO/SiO₂/Si devices upon white light irradiation. The method should be helpful for the design of nanoscale functional self-assembly and expand the application in photovoltaic conversion device.3. Synthesis, structure and physical properties of a novel 11-methyl-benzo[d]pyreno[4,5-b]furan (BPF) and its self-assembly in water have been reported. The performance of nanowire-based film (through drop-casting) in organic light-emitting diodes (OLED) have much better performance (10 times stronger in intensity) than the thin film deposited by directly drop-coating BPF molecules in THF solution. SEM study indicates that the well-organized structure (nanowires) is an important factor to enhance the performance of OLED devices.