苯并[1，2-b：4，5-b’]二噻吩-thieno[3，4-易]thiadiazole导电性的理论研究

采用密度泛函理论，在B3LYP／6—31G（d）水平下，对苯并1，2-b：4，5-b’]二噻吩（BDT）-thieno3，4-b]thiadiaz01e（TD）的低聚物和聚合物进行了理论计算．其中，BDT为电子供体，TD为电子受体，以1：2的方式结合形成化合物，并计算了二面角、分子内的电荷传输、桥键键长和中心键电荷密度．结果显示：随着聚合链增长，共轭程度增加．NICSs值显示：中心环比边环的共轭程度更大．聚合物的能带结构表明：该聚合物的带隙比较低（0．87eV），故其可以作为潜在的导电材料．

Theoretical Study on the Conduction Properties of Benzo[1,2-b：4, 5-b＇] dithiophene-thieno [3,4-b] Thiadiazole System

The oligomers and polymer of benzo1,2-b：4,5-b＇]dithiophene（BDT）-thieno3,4-b]thiadiazole（TD） were studied by the density function theory （DFT） at B3LYP level with 6-31 （G）. Benzo-1,2-b：4, 5-b＇] dithioh- ene （BDT）and thieno -3,4-b] thiadiazole （TD）were used as donor and aeceptor, respectively. The ratio of the pdonor to aceeptor unit was 1：2. The torsional angle, intramolecular charge transfer, bridge bond length and electron density at bond critical points （BCPs） were analyzed. Results indicate that the degree of conjugation increases with main chain extension. The NICSs values show that conjugation in the central is stronger than the outer section. The analysis of band structure shows that the polymer has narrow band gap （0.87 eV）. Therefore, it is a good candidate for conductive material.