Formation and Structure of Pentafluorobenzenethiol Self-Assembled Monolayers on Au(111)

Abstract

The formation of organic self-assembled monolayers (SAMs) onto the metal electrodes is known to be a very effective method to increase the field-effect mobility of organic thin-film transistor (OTFT). It has been reported that the work function of metal can be tuned by using various dipolar SAMs on the metal. Especially, the surface modification of metal electrodes by pentafluorobenzenethiol (PFBT) SAMs have been attracted to enhance the charge injection in OTFTs. To enhance device performance, it is very important to understand molecular-scale features of PFBT SAMs on metal surfaces. In this study, we investigated the surface morphological changes of PFBT SAMs on Au(111) by changing the immersion temperature and concentration of the solution. We revealed that although the adsorption of PFBT molecules on Au(111) at room temperature led to the formation of disordered SAMs, the adsorption of PFBT molecules at 75 °C led to the formation of well-ordered SAMs containing a p 3 structure.