| Autor: |
P. Ziemann, F. Weigl, B. Koslowski |
| Rok vydání: |
2008 |
| Předmět: |
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| Zdroj: |
Surface Science. 602:3714-3720 |
| ISSN: |
0039-6028 |
| DOI: |
10.1016/j.susc.2008.10.015 |
| Popis: |
Exploiting the self-organization of spherical gold salt loaded inverse micelles formed from diblock copolymer poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) in toluene, arrays of Au nanoparticles were prepared exhibiting narrow size as well as interparticle distance distributions. Starting with such Au nanoparticles (average particle diameters ranging between 1 nm and 5 nm) deposited on top of ( 1 1 2 ¯ 0 )-oriented sapphire substrates, thermal desorption spectroscopy (TDS) experiments were performed up to a maximum temperature of 1473 K at a standard rate of 5 K/s in order to test for size dependent vapor pressures as expected from Kelvin’s equation. Opposite to the expected increase of the vapor pressure for decreasing particle diameters, a split desorption behavior is observed with two peaks. Analyzing the data according to the Polanyi–Wigner equation, from the peak at lower temperature a desorption energy and attempt frequency close to bulk Au is extracted while the peak at higher temperature delivers significantly larger values for both properties. The latter observation is attributed to a substrate–nanoparticle interaction, which becomes dominant for decreasing particle diameters. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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