| AVS 54th International Symposium | |
| Surface Science | Wednesday Sessions |
| Session SS2+EM+TF-WeM |
| Session: | SAMs and Organic Films I |
| Presenter: | C. Silien, University of St Andrews, UK |
| Authors: | C. Silien, University of St Andrews, UK M. Buck, University of St Andrews, UK |
| Correspondent: | Click to Email |
The combination of electrochemistry and self-assembled monolayers offers interesting opportunities for nanotechnology due to high resolution defined by patterned SAMs and simplicity and scalability afforded by electrochemistry. However, control of processes such as electrochemical metal deposition on the nanometer length scale requires exact knowledge of the mutual influence of a SAM structure and electrochemical processes. Aiming for an understanding at the molecular level we report an investigation of the underpotential deposition of copper on Au(111) electrodes modified by ω-(4’-methyl-biphenyl-4-yl)-alkanethiols (H3C-(C6H4)-(C6H4)-(CH2)nSH, BPn). As reported recently, this class of molecules gives rise to pronounced structural variations with length n of the alkane spacer and, for n = even, exhibits polymorphism.1,2 Furthermore they can be prepared to an exceptionally high structural perfection. These properties make SAMs of BPn thiols an attractive basis for further tailoring of properties of functionalized electrodes and the electrochemical generation of nanometer-scaled structures. A decisive step in SAM controlled electrometallisation is the deposition of the first layer of metal which takes place in the underpotential region. Its understanding is of crucial importance as this layer forms at the SAM-substrate interface and, therefore, affects the properties of the system. Our in situ STM investigations of the underpotential deposition reveal, firstly, pronounced differences between BPn SAMs and alkane thiols and, secondly, a pronounced influence of the length of the alkane spacer in the BPn SAMs, i.e., whether n = odd or even. The molecular resolution achieved in this study combined with time resolved monitoring of the events occurring in the course of the copper deposition allows us to highlight the relationship between the SAM structure and its influence on the generation of nanometer scaled structures by electrochemical metal deposition.
1 Cyganik, P.; Buck, M.; Strunskus, T.; Shaporenko, A.; Wilton-Ely, J. D. E. T.; Zharnikov, M.; Wöll, C. J. Am. Chem. Soc. 2006, 128, 13868.
2 Cyganik, P.; Buck, M.; Azzam, W.; Wöll, C. J. Phys. Chem. B 2004, 108, 4989.