HIGHLY CONDUCTING POLYPARAPHENYLENE, POLYPYRROLE, AND POLYTHIOPHENE CHAINS - AN ABINITIO STUDY OF THE GEOMETRY AND ELECTRONIC-STRUCTURE MODIFICATIONS UPON DOPING
HIGHLY CONDUCTING POLYPARAPHENYLENE, POLYPYRROLE, AND POLYTHIOPHENE CHAINS - AN ABINITIO STUDY OF THE GEOMETRY AND ELECTRONIC-STRUCTURE MODIFICATIONS UPON DOPING
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DOI：
10.1103/physrevb.29.6761
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发表时间：
1984-01-01
影响因子：
3.7
通讯作者：
CHANCE, RR
中科院分区：
文献类型：
--
作者：
BREDAS, JL;THEMANS, B;CHANCE, RR
在从头算水平上研究了电荷转移掺杂对共轭聚合物几何结构和电子结构的影响。三个系统被选为研究的典型例子与非简并基态共轭聚合物：聚对苯撑，聚吡咯，聚噻吩。作为与给电子掺杂剂的电荷转移的结果，额外的电荷出现在聚合物链上，并诱导强烈的几何形状修改。晶格从芳香结构向类醌结构演化。形成与晶格变形相关的带电缺陷，如无自旋双极化子。对聚合物链的电子结构的影响是这样的，相对于未掺杂的情况下，新的状态出现在差距内。对于实验达到的最大掺杂水平，能带结构计算表明，在差距的状态重叠，形成双极化子带，电子伏特的十分之几宽。这些双极化子带的存在是一致的光学数据，以及与磁性数据表明，在高导电制度的电荷载流子是无自旋的。
The effect of charge-transfer doping on the geometric and electronic structures of conjugated polymers has been investigated at the ab initio level with explicit consideration of the doping agents. Three systems were chosen for study as prototypical examples of conjugated polymers with nondegenerate ground states: polyparaphenylene, polypyrrole, and polythiophene. As a result of charge transfer with electron-donating dopants, extra charges appear on the polymer chains and induce strong geometry modifications. The lattice evolves from an aromatic structure towards a quinoid-like structure. Charged defects associated with lattice deformations such as spinless bipolarons are formed. The influence on the electronic structure of the polymer chains is such that with respect to the undoped case, new states appear within the gap. For the maximum doping levels experimentally achieved, band-structure calculations demonstrate that the states in the gap overlap to form bipolaron bands, a few tenths of an electron volt wide. The presence of these bipolaron bands is consistent with optical data as well as with magnetic data which suggest that the charge carriers in the highly conducting regime are spinless.