Effect Of Length And Benzene Ring And Heptatomic Ring On Rectifying Performance In Fused Oligothilphenes

With the development of social informatization, information processing requirements ofmore and more high, this will inevitably lead to update the corresponding device. Over thepast decades in silicon industry based unit device has been unable to meet the requirements ofThe Times. And further to silicon for material unit device micro process hampered. So peopleexplore bottom-up device processing mode, namely by using molecular as unit device.Inrecent years, single molecule device construction has become an increasing interest inmolecule electronics. As we know, electronic devices incline to be smaller, faster and energysaving.Construction of molecular devices with various special functions using singlemolecules is one of forefront researches in the area of nanoelectronics.Since Aviram andRatner’s prediction in1974that a single molecule could behave as a rectifier, scientists from avariety of disciplines have been engaged in pursuing the understanding of transportmechanisms at the molecular level. Analysis of many attractive properties offered bynano-devices, such as negative differential resistance (NDR) and rectifying performance,shows potential advantages of nano-scale structures. The presence of rectifying performanceis a useful feature that has a wide variety of circuit applications. Moreover, the effect ofmolecular length on rectifying performance is specially investigated. However, there are still anumber of challenges in researching the molecular device.In this present paper, we report results using first principles calculations based on densityfunctional theory (DFT) to investigate the electronic transport of thiophene-based moleculesdevices and oligothiophene derivatives with various side groups. For the all system connectedwith Au electrodes by S–Au bond, we can observe the rectifying performance. While for the Isystem, the rectifying behavior is more obvious. When the oligothiophene derivatives withvarious side groups(J, K, L), the rectifying effect is weakened.