硫化聚并苯导电材料结构的理论化学研究

Theoretical studies on the structure of polyacenic semiconductor materials doped with sulfur atoms

采用量子化学从头算方法和AM1半经验方法,探讨了聚并苯导电聚合物硫掺杂前后结构和电子性质的变化,提出了硫化聚并苯导电材料的“双层夹心”分子结构模型.研究表明,硫化后的聚并苯材料,S原子位于两层聚并苯分子平面中间,并与两个聚并苯分子平面中相应的两个C原子相键合,形成C—S—C“桥式”共价单键;并解释了硫化聚并苯导电材料比本征态聚并苯材料作电极时可逆容量增大的原因.

Quantum chemical methods AM1 and ab initio were used to study the structures of polyacenic semiconductor （PAS） materials in pristine and doped with sulfur atoms. The electronic properties and the geometric parameters of lithium intercalation into PAS were investigated. The results showed that when PAS was doped with sulfur, S atoms were not at the position in PAS rings, but between the parallel rings of PAS. Moreover, a kind of conjugative bond, C--S--C was formed in S-doped PAS, and acted as a bridge between two parallel PAS rings. The theoretical results also indicated that as S-doped PAS was intercalated with lithium ions, the reversible capacity would increase. The theoretical results are in good agreements with the experiment.