Synthesis And Optical-Electrical Property Study Of Star-shaped Molecules Based On Derivatives Of Perylene Bisimides

Perylene bisimides (PBIs) have big molar extinction coefficient, strong ability to absorb light, large conjugated structure and rigid plane, right energy level, high fluorescence quantum yield, excellent photochemical and thermal stability, so they are widely studied and applied in the field of organic semiconductors. And not only that, perylene bisimides have been intensively researched in the field of two-photon. Though the two-photon absorption (TPA) cross section δ of PBIs is very large in the short wavelength region, PBIs’5is too small in the800-1000nm spectrum window. That limits the application of PBIs in the area of two-photon.In order to improve the optical and electrical property of PBIs, based on perylene bisimides star-shaped molecules were attempted to constructed. Star-shaped molecules have the advantage of both small molecule materials and polymer:their structures are well-defined and they possess excellent film-forming properties. Compared with linear molecules, star-shaped molecules extend in all directions and possess isotropy. Star-shaped molecules prevent aggregation of chromophores, increase the fluorescence quantum yield of chromophores in solid film. Further more, star-shaped molecules could exert a collaborative contribution to improve the two-photon properties. In this dissertation, a series of baesd on perylene (naphthalene) imides star-shaped molecules were synthetized and their optical-electrical property was studied, with the hope of them applied in the field of organic photoelectron.1. A novel star-shaped chromophore, Tr-PBI, was constructed by fusing three perylene bisimide branches and a truxene core. Tr-PBI exhibits high photostability and excellent two-photon properties:the maximum of the two-photon absorption cross section8is11000GM at990nm and fluorescence quantum efficiency is0.40in THF. These excellent properties qualify Tr-PBI as a very competitive chromophore for TPA-involving applications.2. A series of star-shaped molecules with fluorene, truxene, pyrene as the cores and perylene monoimide or naphthalene monoimide as the arms were synthetized. Based on naphthalene monoimide star-shaped molecules have high fluorescence quantum yield in solid film, and they have the phenomenon of amplified spontaneous emission in solution state and film state, so they are potential organic laser materials. Based on perylene monoimide star-shaped molecules have strong ability to absorb light and proper energy level. They could not only accept electron, but also accept hole, so they are potential bipolar materials.3. A linear fused perylenebisimide-fluorenone oligomer D9was synthetized. According to reductive cyclic voltammograms and differential pulse voltammograms, D9could accept at least four electrons, and its LUMO energy level is lower than PBIs’. After two cyano groups were introduced. D10also has the ability to accept at least four electrons, and its LUMO energy level is0.12eV lower than PBIs’. Both D9and D10have strong electron accepting ability and they are promising n-type semiconductor candidate.