Abstract
Self-assembled monolayers (SAMs) of 4-[4′-(phenylethynyl)-phenylethynyl]-benzenethiols on Au(111) surfaces are investigated by scanning tunneling microscopy (STM) under ultrahigh vacuum. STM images reveal long-range order in these SAMs with a rectangular unit cell containing two molecules. In high-resolution images, two new structural features are resolved, which cannot be explained by the previously proposed (√3 × 2√3)-R30° commensurate structure which consists of three equivalent domains. First, six equivalent domains are present, and the orientations of these domains with respect to the three 〈121〉 directions of Au(111) are ±5°. Second, superstructures are observed. Periodical ridges are observed as a modulation of the STM imaging contrast within the ordered domains. A new model is proposed, which is very similar to the crystalline structure of p-terphenyl. The closest-packed row is aligned along the next-nearest neighbor or 〈121〉 direction of Au(111) with phenyl planes arranged in a herringbone fashion. The lack of simple commensurate structure of arenethiol SAMs is mainly attributed to intermolecular interactions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9059-9062 |
| Number of pages | 4 |
| Journal | Journal of Physical Chemistry B |
| Volume | 104 |
| Issue number | 39 |
| DOIs | |
| State | Published - Oct 5 2000 |
| Externally published | Yes |
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Cite this
Arenethiols form ordered and incommensurate self-assembled monolayers on Au(111) surfaces. / Yang, Guohua; Qian, Yile; Engtrakul, Chaiwat; Sita, Lawrence R.; Liu, Gang-yu.
In: Journal of Physical Chemistry B, Vol. 104, No. 39, 05.10.2000, p. 9059-9062.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Arenethiols form ordered and incommensurate self-assembled monolayers on Au(111) surfaces
AU - Yang, Guohua
AU - Qian, Yile
AU - Engtrakul, Chaiwat
AU - Sita, Lawrence R.
AU - Liu, Gang-yu
PY - 2000/10/5
Y1 - 2000/10/5
N2 - Self-assembled monolayers (SAMs) of 4-[4′-(phenylethynyl)-phenylethynyl]-benzenethiols on Au(111) surfaces are investigated by scanning tunneling microscopy (STM) under ultrahigh vacuum. STM images reveal long-range order in these SAMs with a rectangular unit cell containing two molecules. In high-resolution images, two new structural features are resolved, which cannot be explained by the previously proposed (√3 × 2√3)-R30° commensurate structure which consists of three equivalent domains. First, six equivalent domains are present, and the orientations of these domains with respect to the three 〈121〉 directions of Au(111) are ±5°. Second, superstructures are observed. Periodical ridges are observed as a modulation of the STM imaging contrast within the ordered domains. A new model is proposed, which is very similar to the crystalline structure of p-terphenyl. The closest-packed row is aligned along the next-nearest neighbor or 〈121〉 direction of Au(111) with phenyl planes arranged in a herringbone fashion. The lack of simple commensurate structure of arenethiol SAMs is mainly attributed to intermolecular interactions.
AB - Self-assembled monolayers (SAMs) of 4-[4′-(phenylethynyl)-phenylethynyl]-benzenethiols on Au(111) surfaces are investigated by scanning tunneling microscopy (STM) under ultrahigh vacuum. STM images reveal long-range order in these SAMs with a rectangular unit cell containing two molecules. In high-resolution images, two new structural features are resolved, which cannot be explained by the previously proposed (√3 × 2√3)-R30° commensurate structure which consists of three equivalent domains. First, six equivalent domains are present, and the orientations of these domains with respect to the three 〈121〉 directions of Au(111) are ±5°. Second, superstructures are observed. Periodical ridges are observed as a modulation of the STM imaging contrast within the ordered domains. A new model is proposed, which is very similar to the crystalline structure of p-terphenyl. The closest-packed row is aligned along the next-nearest neighbor or 〈121〉 direction of Au(111) with phenyl planes arranged in a herringbone fashion. The lack of simple commensurate structure of arenethiol SAMs is mainly attributed to intermolecular interactions.
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UR - http://www.scopus.com/inward/citedby.url?scp=0034300082&partnerID=8YFLogxK
U2 - 10.1021/jp001611g
DO - 10.1021/jp001611g
M3 - Article
AN - SCOPUS:0034300082
VL - 104
SP - 9059
EP - 9062
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 39
ER -