The Study Of Quantum Interference And ?-? Stacking Interaction By Single Molecular Electrical Measurements

With the development of the technologies of single-molecule measurement,the fabrication of metal-molecule-metal junction and molecular devices in microscale have gained much attraction.In this paper,we study the electrical properties of single molecules by notched-wire mechanically controllable break junction technology.In recent years,quantum interference in single-molecule charge transport has attracted a lot of attention.However,there is still quite few studies on the effect of quantum interference in nonalternant hydrocarbons and how to control quantum interference in microscale.In this paper,we study the quantum interference of azulene derivatives with different connection sites of the side groups,and also probe the quantum interference tuning under the protonation of azulene,which is significant in single molecular electronics.Furthermore,we also study the charge transport through supramolecular assembly with ?-? stacking interaction.Detailed research contents and main results are shown as follows:1.We study the azulene derivatives for nonalternative hydrocarbons with different side group connection sites and probe the quantum interference induced by different connectivities.Through experimental and theoretical study,we find that azulenes with 1,3 sites and 4,7 sites show constructive quantum interference and azulenes with 4,6 sites and 5,7 sites show destructive quantum interference.2.Azulene can be protonated by adding strong oxidative acid.In this thesis,we study the tuning of quantum interference by protonation.We find that protonation can tune the charge transport properties and control the quantum interference in azulene derivatives.3.The protonation of azulene derivatives with quantum interference effect is studied through the real-time electronic measurement by MCBJ technology,which proves the feasibility of MCBJ technology used in real-time dynamic measurements.4.The supramolecular assembly of bowl-like molecule and sphere carbon molecule via ?-? stacking interaction is studied by MCBJ technology.It is found that the supramolecular assembly provide comparable conductance with conjugated molecular wires.