Temporal Stability of Thiophene Self-Assembled Monolayers on Au(111)

Abstract

Temporal stability of close-packed thiophene (TP) self-assembled monolayers (SAMs) on Au(111) was investigated by scanning tunneling microscopy (STM). Molecular-scale STM imaging reveals that the structural transitions of TP SAMs in the structure and size of ordered domains and the distribution of vacancy islands (VIs) occurs after long-term storage for 1 year. During this time period, the ordered domain sizes were remarkably increased and the fraction of the areas of the VIs to the total surface area was steeply decreased from 6.5% to 1.7%. We demonstrate that the temporal factor strongly affects two-dimensional SAM structures and our results will be very useful in designing a molecular template for SAM-based further applications.

Keywords:

• scanning tunneling microscopy
• self-assembled monolayers
• surface structure
• temporal stability
• thiophene

Acknowledgments

This work was supported by the research fund of Hanyang University (HY-2005-S), Korea.