载流子在金属/聚对苯乙炔/金属结构中注入及输运的动力学研究

采用紧束缚的Su-Schrieffer-Heeger模型，利用非绝热动力学方法研究了载流子在金属/聚对苯乙炔(poly(p-phenylene vinylene，简记为PPV))/金属三明治结构中注入与输运的动力学过程.发现由于强的电子-晶格相互作用，注入的电荷在PPV链中形成波包，波包的形成与施加在金属电极上的偏压、PPV链上的电场强度及金属电极与PPV之间的界面耦合强度密切相关.在无外电场的情况下，当偏压达到临界值时电荷能够从金属电极注入到PPV链中并形成波包.随着电场强度的增大，波包能 关键词： 金属/聚对苯乙炔/金属结构 载流子输运 波包

Dynamical study on charge injection and transport in a metal/poly(p-phenylene vinylene)/metal structure

On the basis of the tight-binding Su-Schrieffer-Heeger model， the dynamical process of charge injection from metal electrode to a polymer in a metal/poly(p-phenylene vinylene) (PPV)/metal structure has been investigated by using a nonadiabatic dynamic approach. It is found that the injected charges form wave packets due to the strong electron-lattice interaction in PPV. The formation of the wave packet sensitively depends on the applied voltage， the electric field， and the contact between PPV and the metal electrode. In the absence of external fields， the charge can be injected into PPV chain and form wave packet under the critical bias voltage. With the increase of the electric field， the charge carriers can be ejected from PPV to the right metal electrode. But when the electric field becomes high enough， the wave packet can not be formed because it moves too fast in PPV. It is also shown that the number of ejected charges is not an integral multiple of the elementary charge e.