SPM Investigation of Thiolated Gold Nanoparticle Patterns Deposited on Different Self-Assembled Substrates
We present the results of a Scanning Probe Microscopy (SPM) investigation of ordered nanosized metallo-organic structures. Our aim is to investigate the organization and stability of thiolated gold nanoparticles in a compact pattern when deposited onto gold substrates functionalized with self-assembled monolayers made from two molecules that differ essentially in their terminating group: 1,4-benzenedimethanethiol and 4-methylbenzylthiol.
The dodecanethiol capped gold-nanoparticles were synthesized in a two-phase liquid-liquid system. Cluster size-selection by chromatographic technique was performed in order to obtain a narrow core diameter distribution peaked around 2 nm. A Langmuir film of size-selected nanoparticles was formed at the air-water interface using the multi-step creep method and was transferred onto the functionalized substrates.
Overall quality assessment was performed by Transmission Electron Microscopy image analysis. Room temperature scanning tunneling microscopy images of nanoparticles arranged in compact patterns deposited on these functionalized substrates are shown. A high degree of 2-D local organization is found and the role of 1,4-benezenedimethanethiol as grafting element between the gold nanoparticle pattern and the substrate is investigated.
KeywordsLangmuir Film Compact Pattern Scan Probe Microscopy Investigation Step Creep Gold Nanoparticle Pattern
Unable to display preview. Download preview PDF.
- 5.Schaaff, T.G., Shafigullin, M.N., Khoury, J.T., Vezmar, I., Whetten, R.L., Cullen, W.G., First, P.N., Gutiérrez-Wing, C., Ascensio, J., and Jose-Yacamán, M. J., (1997) Isolation of smaller nanocrystal Au molecules: robust quantum effects in optical spectra, J. Phys. Chem. B 101, 7885–7891.Google Scholar
- 6.Heath, J.R., Knobler, C.M. and Leff, D.V. (1997) Pressure /temperature phase diagrams and superlattices of organically functionalized metal nanocrystal monolayers: the influence of particle size, size distribution and surface passivant, J. Phys. Chem. B 101, 189–197.Google Scholar
- 7.Ingram, R.S., Hostetler, M.J., Murray, R.W., Schaaff, T.G., Khoury, J.T., Whetten, R.L., Bigioni, T.P., Guthrie, D.K., and First, P.N., (1997) 28kDa alkanethiolate-protected Au clusters give analogous solution electrochemistry and STM Coulomb staircases, J. Am. Chem. Soc. 119, 9279–9280.CrossRefGoogle Scholar
- 11.Hostetler, M.J., Wingate, J.E., Zhong, C-J., Harris, J.E., Vachet, R.W., Clark, M.R., Londono, J.D., Green, S J., Stokes, J.J., Wignall, G.D., Glish, G.L., Porter, M.D., Evans, N.D., and Murray, R.W. (1998) Alkanethiolate gold clusters molecukles with core diameters from 1.5 to 5.2nm: core and monolayer properties as a function of core size, Langmuir 14, 17–30.CrossRefGoogle Scholar
- 13.Harrell, L.E., Bigioni, T.P., Cullen, W.G., Whetten, R.L., First, P.N. (1999) Scanning tunneling microscopy of passivated Au nanocrystals immobilized on Au(111) surfaces, J. Vac. Sci. Technol B 17, 2411–2416.Google Scholar