Electron Transport Behavior Analysis of Bis(terpyridine) Metal Complex Wires on Electrodes

Abstract

Bis(terpyridine)iron(II) complex (Fe(tpy)2) wires terminated with redox active molecules were sequentially constructed on gold and hydrogen-terminated silicon electrodes. Potential-step chronoamperometry (PSCA) and electrochemical impedance spectroscopy (EIS) were performed to study the electron transfer of ferrocene-Fe(tpy)2 arrays on gold surfaces. The obtained Tafel plots and impedance spectra revealed greater first-order electron transfer rate constant than a ferrocene-terminated alkanethiol self-assembled monolayer and parameters contributing the smooth electron transport. On silicon electrodes, ferrocene-terminated Fe(tpy)2 wires showed slow electron transport between the ferrocene and the electrode while triarylamine-terminated Fe(tpy)2 wires displayed rapid electron transport. The difference of electron transport behaviors was discussed based on the band structure of silicon electrode and the HOMO level of terminal redox units.