中国物理B ›› 2009, Vol. 18 ›› Issue (7): 2961-2966.doi: 10.1088/1674-1056/18/7/057

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Effect of interchain coupling on a biexciton in organic polymers

李元1, 尹笋1, 刘德胜1, 高琨2, 解士杰2, 赵显3   

  1. (1)School of Physics, Shandong University, Jinan 250100, China; (2)School of Physics, Shandong University, Jinan 250100, China;State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China; (3)State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
  • 收稿日期:2008-11-05 修回日期:2008-12-16 出版日期:2009-07-20 发布日期:2009-07-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10804062 and 10874100), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos 200804221005 and 20070422058), and China Postdoctoral Science Foundation funded project (Grant No 20080431171).

Effect of interchain coupling on a biexciton in organic polymers

Gao Kun(高琨)a)b)† , Xie Shi-Jie(解士杰)a)b), Li Yuan(李元)a), Yin Sun(尹笋)a), Liu De-Sheng(刘德胜)a), and Zhao Xian(赵显)b)   

  1. a School of Physics, Shandong University, Jinan 250100, China; b State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
  • Received:2008-11-05 Revised:2008-12-16 Online:2009-07-20 Published:2009-07-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10804062 and 10874100), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos 200804221005 and 20070422058), and China Postdoctoral Science Foundation funded project (Grant No 20080431171).

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摘要： The effect of interchain coupling on the formation and the stability of a biexciton is studied in poly (p-phenylene vinylene) chains in the framework of the tight-binding approach. We obtain an intrachain exciton and biexciton as well as an interchain exciton and biexciton through a double-photon excitation. It is found that a biexciton is energetically favourable to two single excitons even when there exists an interchain coupling. There is a turnover value t⊥C of the interchain coupling for the formation of a biexciton, beyond which two excitons are combined into one biexciton. The binding energy of a biexciton is calculated to decrease with the increase of interchain coupling, which indicates that a biexciton is relatively stable in polymers with a weak interchain coupling. The conclusion is consistent with the experimental observations. In addition, a suggestion about how to improve the yielding efficiency or the formation of biexcitons in actual applications is given.

Abstract: The effect of interchain coupling on the formation and the stability of a biexciton is studied in poly (p-phenylene vinylene) chains in the framework of the tight-binding approach. We obtain an intrachain exciton and biexciton as well as an interchain exciton and biexciton through a double-photon excitation. It is found that a biexciton is energetically favourable to two single excitons even when there exists an interchain coupling. There is a turnover value t⊥C of the interchain coupling for the formation of a biexciton, beyond which two excitons are combined into one biexciton. The binding energy of a biexciton is calculated to decrease with the increase of interchain coupling, which indicates that a biexciton is relatively stable in polymers with a weak interchain coupling. The conclusion is consistent with the experimental observations. In addition, a suggestion about how to improve the yielding efficiency or the formation of biexcitons in actual applications is given.

Key words: biexciton, polymers, binding energy

中图分类号:  (Excitons and related phenomena)

  • 71.35.-y
61.41.+e (Polymers, elastomers, and plastics) 71.15.Ap (Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)) 71.20.Rv (Polymers and organic compounds) 71.38.Mx (Bipolarons)