中国物理B ›› 2017, Vol. 26 ›› Issue (10): 107103-107103.doi: 10.1088/1674-1056/26/10/107103

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Effect of disorder on exciton dissociation in conjugated polymers

Yuwen Feng(冯誉雯), Hui Zhao(赵晖), Yuguang Chen(陈宇光), Yonghong Yan(鄢永红)   

  1. 1. Department of Physics, Tongji University, Shanghai 200092, China;
    2. Department of Physics, Shaoxing University, Shaoxing 312000, China
  • 收稿日期:2017-04-18 修回日期:2017-06-20 出版日期:2017-10-05 发布日期:2017-10-05
  • 通讯作者: Hui Zhao E-mail:zhaoh@fudan.edu.cn
  • 基金资助:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11474218 and 11575116).

Effect of disorder on exciton dissociation in conjugated polymers

Yuwen Feng(冯誉雯)1, Hui Zhao(赵晖)1, Yuguang Chen(陈宇光)1, Yonghong Yan(鄢永红)2   

  1. 1. Department of Physics, Tongji University, Shanghai 200092, China;
    2. Department of Physics, Shaoxing University, Shaoxing 312000, China
  • Received:2017-04-18 Revised:2017-06-20 Online:2017-10-05 Published:2017-10-05
  • Contact: Hui Zhao E-mail:zhaoh@fudan.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Grant Nos. 11474218 and 11575116).

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摘要：

By using a multi-configurational time-dependent Hartree-Fock (MCTDHF) method for the time-dependent Schrödinger equation and a Newtonian equation of motion for lattice, we investigate the disorder effects on the dissociation process of excitons in conjugated polymer chains. The simulations are performed within the framework of an extended version of the Su-Schrieffer-Heeger model modified to include on-site disorder, off-diagonal, electron-electron interaction, and an external electric field. Our results show that Coulomb correlation effects play an important role in determining the exciton dissociation process. The electric field required to dissociate an exciton can practically impossibly occur in a pure polymer chain, especially in the case of triplet exciton. However, when the on-site disorder effects are taken into account, this leads to a reduction in mean dissociation electric fields. As the disorder strength increases, the dissociation field decreases effectively. On the contrary, the effects of off-diagonal disorder are negative in most cases. Moreover, the dependence of exciton dissociation on the conjugated length is also discussed.

关键词: polymer, exciton, electron-electron correlation, dynamical evolution

Abstract:

By using a multi-configurational time-dependent Hartree-Fock (MCTDHF) method for the time-dependent Schrödinger equation and a Newtonian equation of motion for lattice, we investigate the disorder effects on the dissociation process of excitons in conjugated polymer chains. The simulations are performed within the framework of an extended version of the Su-Schrieffer-Heeger model modified to include on-site disorder, off-diagonal, electron-electron interaction, and an external electric field. Our results show that Coulomb correlation effects play an important role in determining the exciton dissociation process. The electric field required to dissociate an exciton can practically impossibly occur in a pure polymer chain, especially in the case of triplet exciton. However, when the on-site disorder effects are taken into account, this leads to a reduction in mean dissociation electric fields. As the disorder strength increases, the dissociation field decreases effectively. On the contrary, the effects of off-diagonal disorder are negative in most cases. Moreover, the dependence of exciton dissociation on the conjugated length is also discussed.

Key words: polymer, exciton, electron-electron correlation, dynamical evolution

中图分类号:  (Self-trapped or small polarons)

  • 71.38.Ht
71.15.Pd (Molecular dynamics calculations (Car-Parrinello) and other numerical simulations) 71.27.+a (Strongly correlated electron systems; heavy fermions)