Injection and transport of electric charge in a metal/copolymer structure

• Published in: Chinese physics B 2011-11, Vol.20 (11), p.438-445, Article 117203
• Main Author: 李冬梅 袁晓娟 马嘉赛 刘德胜
• Format: Article
• Language: English
• Subjects: Barriers; Copolymers; Dynamics; Electric charge; Electric fields; Electric potential; Transport; Voltage; 共聚物; 动力学过程; 弱电场; 电荷注入; 紧束缚模型; 结构; 运输; 金属电极
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/11/117203

The dynamical processes of the electric charge injection and transport from a metal electrode to the copolymer are investigated by using a nonadiabatic dynamic approach. The simulations are performed within the framework of an extended version of the one-dimensional Su-Schrieffer-Heeger （SSH） tight-binding model. It is found that the electric charge can be injected into the copolymer by increasing the applied voltage. For different structures of the copolymer, the critical voltage biases are different and the motion of the injected electric charge in the copolymer varies obviously. For the copolymer with a barrier-well-barrier configuration, the injected electric charge forms a wave packet due to the strong electron-lattice interaction in the barrier, then comes into the well and will be confined in it under a weak electric field. Under a medium electric field, the electric charge can go across the interface of two homopolymers and enter into the other potential barrier. For the copolymer with a well-barrier-well configuration, only under strong enough electric field can the electric charge transfer from the potential well into the barrier and ultimately reach a dynamic balance.