A Crown‐Ether Loop‐Derivatized Oligothiophene Doubly Attached on Gold Surface as Cation‐Binding Switchable Molecular Junction

Abstract

A crown-ether dithiol quaterthiophene is synthesized and immobilized on gold surface by double covalent fixation. UV-vis spectroscopy and cyclic voltammetry show that the corresponding dithioester precursor can complex Pb(2+) in solution and that this property is maintained for monolayers of the dithiol on gold. Current-voltage measurements by eutectic GaIn drop contact on the monolayer show a significant increase (up to 1.6 × 10(3) times) of the current at low bias after Pb(2+) complexation.