嘧啶与苯环对分子器件伏—安特性影响的差异研究

Study on different influence of pyrimidine and phenyl on current-voltage characteristics of molecular devices

利用从头计算方法和弹性散射格林函数理论,对四苯分子和二嘧啶二苯分子电输运性质进行理论研究.结果显示,四苯分子比二嘧啶二苯分子具有更好的电输运能力,二嘧啶二苯分子显示出较好的整流特性.四苯分子较好的电输运性能力源于其部分分子轨道同时与两电极均有较好耦合,而二嘧啶二苯分子中,由于结构的不对称,使得对导电起主要贡献的分子轨道都局域于体系的一端.

By using ab initio method and elastic scattering Green＇s function theory, electronic transportproperties of symmetric tetraphenyl and non-symmetric diblock dipyrimidinyldiphenyl molecules are investigated. The numerical results show that, the tetraphenyl molecule has better electronic conductivitythan the diblock molecule. The diblock molecule exhibits pronounced rectification behavior. Some molecular orbitals of the tetraphenyl molecule are delocalized into the two gold electrodes simultaneously which results in the better electronic conductivity. However, the non-symmetric structure of diblock molecule leads to the localization of the molecular orbitals, which is a disadvantage to the electronic transport.