侧基对π—π耦合双分子结电输运性质的影响

Effect of side groups on electronic transport properties of bimolecular junctions by π-stacking

从第一性原理出发,利用杂化密度泛函理论,结合弹性散射格林函数方法,我们研究了侧基对OPE(Oligophenyleneethynylene)双分子结电输运性质以及两分子间的π-π耦合作用的影响.研究表明,苯环上的侧基影响了两分子间的π-π耦合强度.当侧基为氧甲基时,侧基提高了分子间的π-π耦合作用,促进了分子间电荷的传输.当侧基为叔丁基时,侧基降低了π-π耦合作用,不利于分子间电荷的传输.理论计算结果解释了实验结果.

Using density functional theory and elastic scattering Green＇s function theory, we study effect of side groups on electronic transport properties of bioligophenyleneethynylene molecular junctions and intermolecular π-π interactions at ab initio level. Numerical results show that substituents on the phen- yl rings have significant influence on intermolecular π-π interactions. When the substituent is oxygen- methyl, it promotes the π-π interaction and electronic transport ability. When the substituent is tert- butyl, it reduces the π-πinteraction and electronic transport ability. The theoretical simulations give a good explanation for the recent experimental measurements.