Synthesis And Properties Of Dendritic Blue Light Emitting Materials

With the high-speed development of social productivity level, people's living standards are improved extensively. At the same time, a new generation of flat panel display with more beautiful appearance, superior performance and more convenient to people's production and life, is especially favored by the general public. In short, these high-tech products, such as computer, communication, consumer electronics and car electronics, are shortly called "4 C ". The products with smaller, lighter, more beautiful and transporting large amount of information and images are particularly anticipated by people. O bviously, with the development of future life and information & communication, the current displays and display techniques do not satisfy requirements. Organic electroluminescence(EL)is the phenomenon of light emission from an organic materials under electrical excitation, which was observed more than 50 years ago. For a very long time, it has drawn little attention beyond being an interesting subject for basic studies of charge injection, transport, and light emission processes in molecular crystals while the prospect for applications was largely lacking due to insufficient device performance. Since 1987 the organic light emitting diode(OLED) has dramatically developed. In essence, OLED is an EL device with multilayers and thin- film structures, which is ea sy to fabricate and only requires a low voltage to drive. The key characteristics of OLED can realize highly desires for the flat-panel display application. Thus, an intense research effort followed immediately after its discovery and continued till today, and OLED will be the next generation display which is superior to the LC D. On the other hand, 1,3,5,7-tetramethyl cyclotetrasiloxane and polyhedral oligomeric silsesquioxane(POSS) are nanoscale organic/inorganic hybrid materials, which aroused great interest in the electroluminescent fields. We synthesized two kinds of blue light-emitting materials, 9-allyl-9H-carbazole(allyl-Cz) and 7-ene-butyloxy-3-(2-pyridyl)-coumarin, and then maked the two compounds to graft onto1,3,5,7-tetramethyl cyclotetrasiloxane and the POSS core, and obtained two dendritic blue light-emitting materials. These two materials are organic/inorganic hybrid materials capped with eight carbazolyl subtitents to POSS core or capped with four coumarins derivatives to oligomeric siloxane core.In the thesis, firstly the development of organic electroluminescence(EL) and the light-emitting materials had been introduced. Secondly, a new inorganic/organic hybrid material based on polyhedral oligomeric silsesquioxane(POSS) capped with carbazolyl substituents, octakis[3-(carbazol-9-yl) propyldimethylsiloxy]-silsesquioxane(POSS-8Cz), was successfully synthesized and characterized. The X-ray crystal structure of POSS-8Cz were described. The photophysical property, the morphology and thermal stablity of POSS-8Cz were investigated in detail. Thirdly, a new inorganic/organic hybrid material based on 1,3,5,7-tetramethylcyclotetrasiloxane core capped with four 7-butyloxy-3-(2-pyridyl)-coumarin units was synthesized and characterized, and its photophysical property was investigated. The last, a new dicoumarin blue light-emitting material, 4,4'-bis[(7-N,N-diethylamino)-3-yl-]coumarin-biphenyl, was successfully synthesized and characterized.