3,9-咔唑聚合物基态和激发态性质的理论研究

用密度泛函B3LYP方法对3,9-咔唑低聚物(3,9-carbazole)n(n=1,2,3,4,6,8)]体系进行了全优化, 计算得到电离能、电子亲合势、空穴抽取能及电子抽取能等相关能量, 用ZINDO和TD-DFT方法计算得到吸收光谱; 分析了各种能量的变化及光谱规律. 用外推法由低聚物分子的各种性质与聚合度n相联系得到高聚物的性质, 将所得结果与2,7-咔唑(2,7-carbazole)及类似聚合物进行了比较分析. 结果表明, 3,9位聚合的咔唑整体共轭程度降低, 光谱蓝移, 其IP值和聚芴相近, 可以作为空穴接受材料应用于多层电子荧光器件的空穴传输层. 用CIS方法进行优化得到部分分子的S1激发态结构, 用ZINDO和TD-DFT方法得到对应的发射光谱.

Theoretical Studies on the Ground State and Excited State of Poly ( 3,9-carbazole)

The geometries of the oligomers of(3,9-carbazole)n(n=1,2,3,4,6,8) were fully optimized with the density functional theory/B3LYP . On the basis of the optimized geometries, we calculated the ionization potentials(IP), electron affinities(EA) and other related energies . And we also obtained the absorption spectra using time-dependent density functional theory(TD-DFT) and ZINDO. The properties of poly(3,9-carbazole) were extrapolated by the relationships between the properties of oligomers and the polymerizing chain length n. The results above are studied comparing to those of poly(2,7-carbazole) and similar polymers. The analysis results indicate that the conjugations of poly(3,9-carbazole) are destroyed partly and absorption spectra blue-shift. In addition, the IP value of poly(3,9-carbazole) was similar to that of polyfluorene and thus the poly(3,9-carbazole) can be used as hole transport materials in multilayer electroluminescent devices. Finally we calculated the excited geometries of carbazole and its dimmer by CIS/6-31G and the emission spectra by TD-DFT and ZINDO.