噻吩类电致发光材料的能级结构及光电性能研究

Studies on Energy Levels and Photoeletric Property of Thiophene Compounds in Electroluminescence Devices

用循环伏安法测试了一系列噻吩类聚合物和单体的氧化还原电位,确定了系列化合物的能级结构,比较了主链上不同取代基团及形成共聚物对聚合物能级和光电性能的影响,为高性能发光器件的制作提供了依据。结果表明,随着噻吩环3位取代烷基碳链的增长,单体带隙减小;形成聚合物有利于降低带隙;通过共聚方式引入聚合物主链的(口恶)二唑吸电子基团可以改进其电子传输性能。

A series of regioregular, regiorandom HT, poly-（3-alkylthiophene） and poly（3-alkylthiophene）-co- （1,3,4-oxadiazole） are studied by cyclic voltammetry measurements, using conventional three electrodes system. The conversion formula between redox potential and HOMO, LUMO energy levels are obtained. Their HOMO and LUMO energy levels and band-gap energy are calculated from the cyclic voltammetry and u-v vis. The effects of alkyl substituent and the introduction of oxadiazole moiety in the main chain on the energy level and photoelectric property are compared. It is found that band gaps of monomers are reduced with an increase of the length of alkyl chain, and copoly-thiophene containing 1,3,4-oxadiazole in main chain enhances the electron-transporting effect while decreases the holetransporting effect. With its band-gap energy further decreased, copoly-thiophene might be promising material for applications in high performance polymer light-emitting diodes.