Characteristics and fabrication of oligophenyleneethynylene thiol self-assembled monolayers

Alkanethiols containing carboxylic acid in the tail group have been used as the receptor for the immobilization of biomolecules in biosensor and biomolecular device. However, the alkanethiol shows low electroactivity and sensitivity because of the flexibility of chain and poor electrical properties. In the present work, we have synthesized 4-(2-(4-(acetylthio)phenyl)ethynyl)benzoic acid (APBA) with conjugated structure, and then the self-assembled monolayer (SAM) was fabricated on a gold substrate. The electrical conductivity and electrochemical activity of the prepared SAMs were investigated from the measurements of scanning tunneling microscope (STM) and cyclicvoltammetry (CV).