联苯二胺分子器件电输运特性的取代效应

在第一性原理基础上,理论研究了苯环上含有不同取代物的四个联苯分子的电输运特性.计算结果表明,当苯环上的氢被取代时,联苯分子的两个苯环之间的扭转角增大.分子结的电导随苯环间扭转角的增加而减少,且电导值与扭转角余弦平方成线性关系.在低偏压下,分子结的电输运机制是电子通过π轨道的隧穿过程.计算结果与实验结果符合的较好.

The substituted effect on electronic transport properties of biphenyl molecular devices

The electronic transporting properties of biphenyl molecules with different ring substitutions are studies at the first-principles level. The results show that the twist angle between the two benzene rings increases as the hydrogen atoms in the ring are substituted. Consequently, the junction conductance decreases as the increases. Furthermore, it demonstrates that the junction conductance has a linear relation with , which indicates that the tunneling transport through the -orbitals plays a dominant role for the junction conductance at low bias. The simulation results are relatively consistent with the measurement.