PNB聚合物的激子及其对静电场的响应

Exciton in a PNB Polymer and Its Response to Electrostatic Fields

在Baranowski B櫣ｔｔｅｒｎｅｒ Voit模型的框架内 ,得到了PNB聚合物有限长开链的自隐激子态 .研究了静电场对激子的影响 ,发现电场对激子的电荷密度、能级、扭角序参量、键序位形都有较明显的影响 ;并使激子吸收峰从红外波段进入可见光波段 .当电场超过 0 .74MV cm时 ,激子解离成一对正反纽结孤子 ,此时 ,激子吸收峰分裂成 1.1和 1.4eV左右的两个峰 ,分别对应于电子型孤子和空穴型孤子 .由此对实验上已观察到 1.0和 1.3eV两个短寿命低能吸收峰的成因作出了解释 .

Self trapping exciton state is obtained for an open chain of a PNB polymer with finite length, in the framework of the Baranowski Bütterner Voit model. The results shows:an electric field makes notable effects on the charge density, ring torsion angle and bond lenth configuration of the exciton. And it makes the absorption peak of the exciton move to higher energy. While the electric field is stronger than 0.74 MV/cm, the exciton is dissociated into a soliton and an anti soliton, and the single peak of the exciton absorption is splitted into two peaks at 1.1 eV and 1.4 eV, associated with the electron soliton and hole soliton. Based on the results, we attribute the absorption peaks at 1.0 eV and 1.3 eV observed in the polymer to the pair of solitons.