Synthesis And Properties Of Novel Symmetric Luminescent Materials Containing Carbazole Derivative Compounds

Carbazole is a kind of compound which has a stable planar conjugated rigid structure as well as a fused ring structure,it also has a good photoelectric properties of the group.The nitrogen atom of this structure has solitary electron pairs and planar conjugate rigid structure,making it not only has good thermal stability,but also could have a multi-site chemical reaction.Designing carbazole in the photoelectric functional materials can not only ensure a good photoelectric properties,but also expand the scientific research personnel on the design of the idea.The current use and research of carbazole groups is to introduce it into the main chain by conjugation and the polymer chain in a different polymerization manner to form a polymer material.But there is little report about the combination of carbazole in the alkyl chain to the target compound.As the carbazole group linked in alkyl chain has the characteristics of electrons,it also has a photoelectric properties and good charge transport properties,which make such materials has great potential in the field of optoelectronic materials.The solubility is a very important condition in the organic luminescent material and the introduction of alkyl chains in the compound can effectively improve the solubility and also promote high-quality thin film deposition.The thermal stability of organic compounds is the key to the stability and longevity of optoelectronic devices.Carbazole derivatives are a class of compounds that exhibit strong blue light emission,high Tg temperature and thermal stability effects,making them become attractive candidates for OLEDs.In this paper,three kinds of carbazole derivatives with strong blue luminescence and high stability were designed and synthesized.The thermal and chemical properties of the spectra were characterized by DSC and TGA.And its photochemical properties were studied,the electrochemical performance was studied by cyclic voltammetry and application potential in photoelectric conversion was explored.By characterizing and comparing the chemical and thermochemical properties of the three target compounds,it is shown that the carbazole group can effectively improve the thermal stability of the target compound and improve the liquid quantum efficiency of the target compound.The fluorescence quantum efficiency of the solution of the target compound in DMF,THF and DMSO is more than 70%.The results show that the quantum yield of the target compounds increases with the increase of the number of carbon atoms,and the quantum yield of the liquid fluorescence decreases with the increase of the carbon chain,and the liquid fluorescence of the target compound decreases with the increase of the carbon number of the target compound.Quantum efficiency is significantly greater than that of solid-state fluorescence quantum.The average lifetime of the four carbon target compounds in THF solution was 8.02 nanoseconds and the average lifetime at solid state of the two carbonaceous compounds was 1.04 nanoseconds,the average activity of the two carbonaceous compounds in the THF solution was 8.02 nanoseconds.The solid lifetime of 4 carbon target compounds is 1.17 nanoseconds.The fluorescence lifetime is in the order of nanosecond,which is the life span of the typical ?-? * transition,and its fluorescence lifetime is equivalent to that of the singlet exciton,which indicates that the compound luminescence is mainly single-phase exciton luminescence.From the electrochemical analysis,it was found that the HOMO level of the target compound was-5.31 eV to-5.33 eV and the LUMO level of the target compound was-1.84 eV ~-1.83 e V.The thermal stability of the target compound was 425 ?,415 ? and 356 ?,respectively.The results showed that the target compounds had thermal stability.From the electrochemical and theoretical calculations we can see that the target compound has intramolecular charge transfer properties.