Studies On Synthesis, Characterization And Application Of Organic Optoelectronic Materials Based On Heterofluorenes

Due to its intriguing advantages such as low driving voltage, high luminescence, wide view angle, quick response and simple fabrication processes, organic light emitting device (OLED) has become a novel technology for panel display, and it also has been the first choice of environment friendly light technique. Heterofluorenes have become a new series of widely investigatedπconjugated materials for OLED because of its interaction between heteroatom andπconjugated backbone. In this dissertation, several carbazole end capped heterofluorenes (CzHFs) designed by structurally mimicking 4,4'N,N'dicarbazole biphenyl (CBP) via connecting the biphenyl core of CBP with the linking atom of C, P, N, O, and S, respectively, were synthesized successfully and their optoelectronic properties and the performance of their devices were investigated.In this dissertation, CzHFs were successfully synthesized by the optimized Ullmann C N cross coupling reaction between carbazole and dibromoheterofluorene monomers. For further study the relationship of the molecular structures and optoelectronic properties of the heterofluorene derivations, the optoelectronic properties were detailedly discussed through DFT calculations, optophysical analysis and the device characteristics. The results show that they are a kind of promising green, red, and even blue host materials for phosphorescent light emitting diodes (PHOLEDs) with more desirable localization and energy level of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and also higher triplet energy compared with those of CBP. Those devices with m CzHFs as host materials have excellent performance for use in next generation flat panel displays with the merits of low driving voltage, high luminescence and high efficiency.