Study On Design, Synthesis And Characterization Of Novel Organic Electroluminescent Functional Molecules Based On Carbazole

Organic electroluminescent materials have attracted much attention in the research of optoelectronic information materials for the various advantages compared with inorganic light-emitting diodes. In this dissertation, a series of carbazole derivatives for organic light-emitting diodes were designed and synthesized. Then their optoelectronic properties were investigated. The dissertation was divided into the following parts:Firstly, a family of star-shaped molecules with three sidearms were designed and synthesized by Suzuki coupling reaction. The chemical structures of the compounds were confirmed by ~1H NMR, MALDI-TOF-MS, and elemental analysis. Then these compounds were examined by UV-vis and fluorescence emission spectrum (PL) and they all exhibited good blue fluorescence with maximum wavelengths ranging from 415 nm to 427 nm. Cyclic voltammetry illustrated that the materials had high HOMO energy levels, implying that they had good hole-injecting and hole-transporting properties. Thermal analyses indicated that these compounds were highly thermal stability and high glass transition temperature (Tg), so these compounds can be applied as good hole injecting and transporting material in Organic Light-emmitting Devices (OLEDs).Secondly, we synthesized two star-shaped molecules with six sidearms by Suzuki coupling reaction and their chemical structures were characterized by ~1H NMR, MALDI-TOF-MS and elemental analysis. These compounds were examined by UV-vis and fluorescence emission spectrum and they also exhibited good blue fluorescence with the maximum wavelengths at 422 nm. Cyclic voltammetry illustrated that the materials had high HOMO energy levels, implying that they had good hole-injecting properties. Thermal analyses indicated that these compounds were highly amorphous stability and high glass transition temperature (Tg).Finally, a family of carbazole-naphthalimide derivatives were designed and synthesized. These compounds exhibited good green fluorescence with the maximum wavelengths ranging from 514 nm to 542 nm. There were intermolecular energy transfers because of both electron-donor carbazole group and electron-acceptor naphthalimide group in the molecules. Cyclic voltammetry illustrated that the materials had low HOMO energy levels. The compounds had not glass transition temperature due to the great polarity of molecules. These compounds can be applied as good dopant emitter with hole-transporting in OLEDs.