Impedance Spectroscopy of Composite Monolayer Controlled Electron-transfer Rate

Composite mQnQlayers composed of hydroxythiophenol(HTP)and hexadecanthiol (HDT) were fabricated from a solution of the thlols to control and manipulate the microscopic envifonment of redox reactions，While self-assembled monolayer of HTP on a gold eiectrode permitted a redox reaction of indigotetrasu】fonate，that of HDT blocked the redox reactiQn．The charge-transfer resistance of lndigoIetraulfonatc on a monolayer，which can bc taken as the electron-tunnehng resistance，was570Ωcm2for HTP，and over l20kΩcm2for HDT．The Capacitances and resistances of the monolayers were useful in determinating the composition of composite monolayers．The ac impedance data of composite monolayers suggesUhat the angle of molecular orientation on gold e畳ectrodes has a subtle influence onこhe electrQn一しransfer rate of redox species． 1緒言 機能性チオール分子を用いた自己集合膜電極の研究 は非常に多岐にわたっている1