The Study Of The Self-assembly Of Azobenzene-perylene Diimide And Doping In Graphene

Perylene diimide derivatives have been extensively investigated as a kind of building blocks in the field of supramolecular self-assembly due to their excellent photochemical and thermal stability and high quantum yield of fluorescence and ?conjugated rigid plane. Graphene, a two-dimensional carbon material, has many excellent properties. But the inert surface and not easy dispersion have brought the huge barriers for its research and application. Noncovalent functionalization method can not only retain the excellent properties, but also can improve the dispersion and endow them with new properties. So the noncovalent modification is widely used in the process of the functionalization of graphene. In this paper, We develop perylene diimide derivatives as the backbone and modified with photoresponsive photochromic groups-fluorided azobenzene at the bay position of perylene diimide. Through changing molecular configuration by irradiation with specific light, we have investigated the dynamics of the molecular self-assembly behavior and its response to light stimulation and realized effective light modulation of its self-assembly process initially. Moreover, The graphene complex is obtained by modified with the azobenzene-perylene diimide derivatives molecule. The dispersion of graphene in organic solvent is improved and the application in the field of molecular switches and photomemory and sensors is also expanded.1. We have designed and synthesized a new type of highly fluorinated azobenzene-perylene diimide(FAZO-PDI) molecules. The isomerization kinetics process irradiated with UV light and visible light is studied by UV-visible absorption spectra. The isomerization process follows the first-order reaction kinetics equation and the kinetics constant is 1.087 x 10-2 s-1, which demonstrates that its photoresponse is fast and stable.2. The self-assembly behavior and morphology in the methanol solution is studied by UV-vis absorption spectra and scanning electron microscope. Under 365 nm UV irradiation, the configuration of fluorined azobenzene group change from E to Z, and the self-assembly nanostructures transform correspondingly from the highly ordered one-dimensional nanostructure of nanorods or nanobelts to nanospherical due to the bend of Z configuration.3. After the adsorption between FAZO-PDI molecules and graphene by ?-?interaction, the graphene composite is obtained successfully. TG analysis shows themass fraction of FAZO-PDI molecules in the composite is about 8%. The significant fluorescence quenching in the adsorption process is observed by fluorescence emission spectrum. Several electron micrographs of the composite show the ?-?adsorption interaction between them are relatively homogeneous. Moreover, the photoresponse of the composite is demonstrated by UV-visible absorption spectroscopy and the photoresponse is fast and stable. Graphene modified with azobenzene can be applied for information accumulation and optical switching and new graphene based optical switching devices.