Synthesis And Characterization Of Novel Phosphorescent Materials Based On Carbazole And Triphenylpyridine Derivatives

Since organic light emitting diode(OLED)was firstly reported by C.W.Tang in 1987,tremendous progress has been made in OLED.These days,OLED can be found in mobile phones,computers,televisions and solid lighting resource.Both academia and industry are devoting increasing effort to design and synthesize excellent materials to improve the efficiency of devices,but there are still some problems in OLED,such as short life time and low quantum efficiency.So designing materials with excellent properties is the key to solving the above problems.In this dissertation,two series novel phosphorescent host materials were designed and synthesized from carbazole and triphenylpyridine,respectively.The intermediates and desired compounds were characterized by NMR and elemental analysis.The physical properties of these compounds were characterized by thermogravimetric analysis,differential scanning calorimetry,UV-vis absorption and fluorescent spectras,and cyclic voltammetry measurements.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)density maps were demonstrated by density functional theory(DFT)calculations at the gaussian 09 with 6-311G(D,P).The obtained results were as follows:1.The important intermediates,3-bromo-9-(4-benzylbromo)carbazole and 3-bromo-9-(2-benzylbromo)carbazole,were synthesized from carbazole,and then reacted with aryboronic acid to synthesize desired compounds.The characterizations of these compounds were performed by means of NMR and elemental analysis methods.2.The triphenylpyridine based phosphorescent host materials were synthesized by using 2,6-bis(4-bromophenyl)-4-phenylpyridine which was synthesized from benzaldehyde and 1-(4-bromophenyl)ethanone,reacting with arylboronic acid,and characterized by NMR and elemental analysis.3.Ten novel host materials were synthesized successfully,the test results showed that:all compounds possessed high decomposition temperatures(higher than 400 ?)and glass transition temperatures(higher than 90 ?),the triplet energy higher than 2.60 e V,which is benefit for energy transfer from host to dopant.The electrochemical test results showed that all compounds possessed proper HOMO/LUMO energy levels,which is benefit for carriers transfer.The results of DFT calculations showed that the density maps of FOMs are separation,which showed that these compounds may possess bipolar property.All materials show great application potential in electroluminescent devices.