Single Gold Atom Containing Oligo(phenylene)ethynylene: Assembly into LB Films and Electrical Characterization
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- 作者：Luz M. Ballesteros ; Santiago Mart铆n ; Santiago Marqu茅s-Gonz谩lez ; Mar铆a C. L贸pez ; Simon J. Higgins ; Richard J. Nichols ; Paul J. Low ; Pilar Cea
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：January 8, 2015
- 年：2015
- 卷：119
- 期：1
- 页码：784-793
- 全文大小：466K
- ISSN：1932-7455
文摘
Monomolecular films of an oligo(phenylene)ethynylene, OPE, derivative [2-isocyano-1,3-dimethylbenzene][4-(4鈥?aminophenylethynyl)phenylethynyl]gold, 1, containing a gold atom in the molecule backbone have been prepared by the Langmuir鈥揃lodgett (LB) method in order to study how the electrical properties can be modulated in monolayers of OPEs by incorporation of a gold center in their structures. UV鈥搗is reflection spectra of Langmuir monolayers of 1 at the air鈥搘ater interface reveal strong aurophilic interactions between neighboring molecules that increase upon compression. Monolayer Langmuir鈥揃lodgett (LB) films were readily fabricated by the transfer of Langmuir films of 1 onto solid substrates. Quartz crystal microbalance (QCM) experiments conclusively demonstrate formation of monolayer LB films with a high surface coverage. The morphology of these films was analyzed by atomic force microscopy (AFM), revealing formation of homogeneous layers with an optimum surface pressure of transference of 6 mN路m鈥?. Film homogeneity and integrity was confirmed by cyclic voltammetry, with efficient blocking of gold electrodes by these well-formed monolayers of 1. The electrical properties of LB films of 1 were investigated by scanning tunneling microscopy (STM) using a 鈥渢ip-to-contact鈥?method. Characteristic shape for a tunneling junction (Simmon鈥檚 type behavior) I鈭?i>V curves were observed, with analysis of the pseudolinear (ohmic) region giving a conductance value G = 3.9 脳 10鈥? G0, which is relatively high for an OPE derivative and may indicate a beneficial role of metal atom incorporation within the wire-like system.