中国物理B ›› 2003, Vol. 12 ›› Issue (5): 548-552.doi: 10.1088/1009-1963/12/5/316

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Electronic confinement in quasi-one-dimensional triblock copolymers

王鹿霞1, 刘德胜2, 解士杰3, 韩圣浩3, 梅良模3   

  1. (1)School of Physics and Microelectronics, Shandong University, Jinan 250100, China; (2)School of Physics and Microelectronics, Shandong University, Jinan 250100, China; Department of Physics, Jining Normal University, Jining 272025, China; State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China; (3)School of Physics and Microelectronics, Shandong University, Jinan 250100, China; State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
  • 收稿日期:2002-11-29 修回日期:2003-01-29 出版日期:2003-05-16 发布日期:2005-03-16
  • 基金资助:
    Project supported by the Major Program of the National Natural Science Foundation of China (Grant No 90103034), and the National Natural Science Foundation of China (Grant Nos 10074040 and 60176021).

Electronic confinement in quasi-one-dimensional triblock copolymers

Liu De-Sheng (刘德胜)abc, Wang Lu-Xia (王鹿霞)a, Xie Shi-Jie (解士杰)ac, Han Sheng-Hao (韩圣浩)ac, Mei Liang-Mo (梅良模)ac   

  1. a School of Physics and Microelectronics, Shandong University, Jinan 250100, China; b Department of Physics, Jining Normal University, Jining 272025, China; c State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
  • Received:2002-11-29 Revised:2003-01-29 Online:2003-05-16 Published:2005-03-16
  • Supported by:
    Project supported by the Major Program of the National Natural Science Foundation of China (Grant No 90103034), and the National Natural Science Foundation of China (Grant Nos 10074040 and 60176021).

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摘要： A tight-binding calculation to describe the triblock copolymer xPA(polyacetylene)/nPPP (poly(p-phenylene))/yPA or xPPP/nPA/yPPP is presented. The interfacial coupling between homopolymer segments is attributed to the hopping of π-electrons and the coupling of σ-bonds. The dependence of the band gap of triblock copolymers on the interfacial couplings or on the composite segment lengths is studied. The influence of composite segment lengths on the electron density is also studied. For nPPP/xPA/nPPP structures, the band gap varies with PA segment length over a wide range of 1.32－2.74eV. For nPA/xPPP/nPA structures,the band gap is invariant with PPP segment length. It is found that a spontaneous tunnelling phenomenon could take place in nPA/xPPP/nPA structures. Furthermore, the polaron caused by doping an electron into nPA/xPPP/nPA will tend to be confined in one of the well (PA) parts. This kind of confinement may increase the electron－hole recombination probability.

Abstract: A tight-binding calculation to describe the triblock copolymer xPA(polyacetylene)/nPPP (poly(p-phenylene))/yPA or xPPP/nPA/yPPP is presented. The interfacial coupling between homopolymer segments is attributed to the hopping of $\pi$-electrons and the coupling of $\sigma$-bonds. The dependence of the band gap of triblock copolymers on the interfacial couplings or on the composite segment lengths is studied. The influence of composite segment lengths on the electron density is also studied. For nPPP/xPA/nPPP structures, the band gap varies with PA segment length over a wide range of 1.32－2.74eV. For nPA/xPPP/nPA structures,the band gap is invariant with PPP segment length. It is found that a spontaneous tunnelling phenomenon could take place in nPA/xPPP/nPA structures. Furthermore, the polaron caused by doping an electron into nPA/xPPP/nPA will tend to be confined in one of the well (PA) parts. This kind of confinement may increase the electron－hole recombination probability.

Key words: organic quantum well, copolymer, electronic confinement

中图分类号:  (Polymers and organic compounds)

  • 71.20.Rv
71.15.Ap (Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)) 73.20.Mf (Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)) 73.40.Gk (Tunneling) 71.38.-k (Polarons and electron-phonon interactions)