Study On Synthesis Of Conjugated Compounds Which Containing Carbazole, Fluorene Rings And Their Optical Properties

Organic electroluminescence,which called organic light emitting diode (OLED) is one of the research forefronts in the field of flat display recently. Compared with inorganic electroluminescent materials,OLED posses excellent features such as simple structure,high luminescence efficiency,low energy consumption,high brightness,wide visual view,fast response,low driving voltage and so on,which be considered as a new technology to instead of LCD in the near future.People pay more attention to this field for a long time.As the foundation of organic electroluminescence devices,OEL materials are one of the key factors influencing the device performance.At present,scientists concentrated on the study of luminescent materials,new product and manufacture of devices about OLED.As hole-transporting and electroluminescent materials,carbazole and fluorene derivatives play an important role in OLED research field. Carbazole ring has excellent hole-transporting ability,which definitely hinder the crystallization process,thus prolong their lifetime values and get high luminescence efficiency.Fluorene and its derivatives are organic electroluminescent materials which have an aromatic biphenyl structure with wide energy gap in the backbones and high luminescent efficiency.It is very helpful to improve the thermal and spectral stabilities by introducing the 2,7-dibromofluorenone units into the electroluminescent molecules.Based on the full and carefull investigation of the literature,we carried out the work including the following aspects:1.Twelve bicarbazole rings' conjugated compounds were synthesized by following steps.First,two compounds containing bicarbazole rings were synthesized by carbazole and 1,4-diiodinebenzene or 4,4'-diiodinediphenyl separately,then iodine group was introduced in the 3,6 positions of dicarbazole rings,finally,arylamine groups such as diphenylamine,1-naphyl-phenyl amine,carbazole were introduced to dicarbazole rings.The structures of these compounds were characterized by IR,~1H NMR and so on,the structure of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl was confirmed by single crystal X-ray. Through the study on the synthetic condition of 3-iodine-1,4-dicarbazolephenyl and 3-phenyl-1,4-dicarbazolephenyl,we received a better synthetic route.2.At fluorene as the starting material,six substituted aromatic schiff base compounds of 2,7-dibromofluorenone were synthesized by oxidation, bromination and reaction with arylamine compounds which have different substituted groups.The structures of these compounds were characterized by IR,~1H NMR,MS and UV-vis,the structure of N-(2,7-dibromo-9H-fuoren-9-ylidene) naphthalen-2-amine was confirmed by single crystal X-ray,modified the 2,7-positions of substituted aromatic schiff base compounds of 2,7-dibromofluorenone, arylamine group such as diphenylamine,1-naphyl-phenyl amine,carbazole were introduced into three organic small molecule conjugated compounds which containing fluorene ring.3.The photophysical processes of three imino derivatives of 2,7-dibromofluorenone: N-(2,7-dibromo-9-fluorenylidene)aniline(NBFA),4-chloro-N-(2,7-dibromo-9-fluorenylidene) aniline(CNBFA),4-methyl-N-(2,7-dibromo-9 -fluorenylidene)aniline(MNBFA) were separately determined by the UV-vis absorption and fuorescence emission spectra in different solvents.The results showed that the change of substituted group and solvent polarity have effect on these compounds' maximum absorption wavelength and fluorescence intensity.The absorption and fluorescence spectra of these compounds exhibited red-shifted in weak polarity solvent and with donating electron group.the fluorescence emission intensity of MNBFA can be quenched by diphenylketone and triethylamine,the quenching process followed the Stern-Volmer equation well.