Exction Migration Induced By Collision With A Polaron In Conjugated Polymers

Organic polymers have attracted the attention of people.because of the characters of polymer,semiconductor and metal conductor.On the one hand,it offers pepole a new material,such as organic conductor,organic semiconductor and organic superconductors;On the other hand,through the research of its conductive mechanism,it prompts many basic subject of physics make advances,such as condensed matter physics and so on.During the process of the research of the polymer, we know that in most of the previous works, charge carriers are actually created in a numerical way. That is, the charge carrier is directly put to the polymer chain by hand. Although this way of introducing charge carriers is convenient, it might lose some important information of real processes. In real optoelectronic devices as is known, charge carriers are usually introduced to the polymer chain by injection from other materials. We have known that negative polarons can be injected into a polymer chain by enhancing the electrostatic potential of the source electrode. Thus it is possible for us to simulate the collision between an injected polaron with the exciton in a polymer chain.This essay will mainly discuss the scattering process between an injected polaron and the exction in the presence of external electric fields.In the first chapter, we discuss the basic structure of polymer and Peierls phase transition theory.In the second chapter, we introduce a classical model----SSH model.In the third chapter,we focus on based on the scattering process between an injected polaron and an exciton in the presence of an electric field in a conjugated polymer chain. It is found that the polaron can always cross the exciton in the presence of an external electric field. In contrast, the behavior of the exciton strongly depends on the electric field strength. If the field strength is greater than a critic value of about3.0×103/cm, the exciton has no change after the collision with the polaron. However, if the field strength is less than the critic value, the exciton has an obvious migration in the opposite direction of the moving polaron. This migration of exciton under weak electric fields is originally attributed to a slow scattering process with the charged polaron.In the fourth chapter, summaries are given.