物理化学学报 >> 1993, Vol. 9 >> Issue (02): 256-262.doi: 10.3866/PKU.WHXB19930222

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聚二乙炴电子能带结构的研究

张启元; 严继民; 张大仁   

  1. 中国科学院化学研究所,北京 100080;中国科学院生态环境研究中心,北京 100083
  • 收稿日期:1991-09-30 修回日期:1992-05-08 发布日期:1993-04-15
  • 通讯作者: 张启元

Investigation on the Structure of Electronic Energy Bands of Polydiacetylenes

Zhang Qi-Yuan; Yan Ji-Min; Zhang Da-Ren   

  1. Institute of Chemistry, Academia Sinica, Beijing 100080; Center of Eco-Environmeat, Academia Sinica, Beijing 100083
  • Received:1991-09-30 Revised:1992-05-08 Published:1993-04-15
  • Contact: Zhang Qi-Yuan

关键词: 聚二乙炔, 电子能带结构, 有机半导体, EHCO-ASED

Abstract: The influences of the side phenyls (PHs) on the electronic energy band-structure of polydiaeetylenes have been studied by quantum-chemical EHCO-ASED method. When the backbone are changed from polybutatriene(PBT) to polydiacetylene(PDA), the band widths △E_(HO) and △E_(LU) decrease montonically from those of PBT to PDA, but the energy gap decreases from E_g(PBT)=0.43 eV to the minimum E_g(MIN)=0.11 eV firstly, and then increases to E_g(PDA)=1.43 eV (Table 2). Corresponding to the minimum, there is a symmetry inversion for HOCO and LUCO (Table 3). When PHs are coplanar with the backbone (PBT-PH1 and PDA-PH1), they will take part in the conjugation of the system to a certain extent (Table 5), and cause: (I) energy gaps E_g (PBT-PH1) and E_g(PDA-PH1) to change to 56% of E_g(PBT) and 76% of E_g(PDA) respectively (Table 4); (II) the band widths, both ΔE_(HO) and ΔE_(LU) for PBT-PH1 and PDA PH1, to decrease to 40—50% of those of PBT and PDA respectively (Table 4). When PHs are perpendicular to the plane of the backbone (PBT-PH2 and PDA-PH_2), the influences of PHs on the band structure are limitted (Table 4). According to the results and the discussions in this paper, it is shown that the intrinsic semiconductor characteristic of polydiacetylenes is hard to be improved obviously by the side group.

Key words: Polydiacetylenes, Structure of electronic energy bands, Organic semiconductor, EHCO-ASED