电子传输材料噻二唑衍生物的密度泛函研究

Density Functional Theory Studies on the Thiadiazole Derivatives as Electron Transporting Material

用密度泛函B3LYP方法对7种3-(3'-吡啶基)-6-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑分子进行全优化,所有化合物都是平面分子.计算了分子的垂直电子亲和势(VEA)、绝热电子亲和势(AEA)、分子内重组能以及绝对硬度等相关能量,结果显示化合物的HOMO与LUMO能级可通过连接不同取代基进行调节,变化幅度为0.346～1.10eV.分子内重组能证实3-(4'-氰基-3'-吡啶基)-6-芳基-1,2,4-三唑并[3,4-b]-1,3,4-噻二唑是很有前途的电子传输材料,不同取代基所对应的化合物分子内重组能也不同.绝对硬度数据与分子内重组能都表明,化合物E,G难于传输电子.用TDDFT方法计算了化合物A,B和C的吸收光谱,与实验值相比,最大吸收峰的差值在3～10nm之间.

Seven 3-（3＇-pyridyl）-6-aryl- 1,2,4-triazolo[3,4-b]- 1,3,4-thiadiazote derivatives have been studied at the B3LYP/6-31G＊ level of density functional theory （DFT）. All the compounds have planar structure, and adiabatic and vertical electron affinities, intramolecular reorganization energies and absolute hardness have been obtained. The results on the basis of the theoretical calculations indicate that the HOMO and LUMO energies of the substituted molecules can be tuned by changing the substituents. These changes lead to energy shifts in the order of 0.346-1.10 eV. The intramolecular reorganization energies confirm that 3-（4＇-cyanogen-3＇-pyridyl）-6-aryl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazole is a good candidate for electron transport materials. By having simple substituents at proper positions one can control the reorganization energy, which in turn indicates that electron transport properties can be tuned. The data of absolute hardness agree that compound E and G are difficult to transport electron. The absorption spectra of compounds A, B and C are obtained by using TD-DFT, and the difference of maximum absorption peaks are from 3 to 10 nm compared with the experimental data.