Pronounced Odd−Even Changes in the Molecular Arrangement and Packing Density of Biphenyl-Based Thiol SAMs:  A Combined STM and LEED Study

Self-assembled monolayers (SAMs) of ω-(4‘-methylbiphenyl-4-yl) alkanethiols CH3(C6H4)2(CH2) n SH (BPn, n = 3 and 4) on Au(111) substrates were studied using scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). Preparation at elevated temperature results in highly ordered l...

Full description

Saved in:
Bibliographic Details
Published in:Langmuir 2003-09, Vol.19 (20), p.8262-8270
Main Authors: Azzam, W, Cyganik, P, Witte, G, Buck, M, Wöll, Ch
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Self-assembled monolayers (SAMs) of ω-(4‘-methylbiphenyl-4-yl) alkanethiols CH3(C6H4)2(CH2) n SH (BPn, n = 3 and 4) on Au(111) substrates were studied using scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). Preparation at elevated temperature results in highly ordered layers with large domains. Whereas the (2√3 × √3) structure of the BP3 SAMs is similar to that reported previously for other aromatic thiols, SAMs made from BP4 exhibit a very different structure. A (5√3 × 3)rect unit cell containing 8 molecules is found which corresponds to a packing density reduced by 25% compared to that of BP3. The odd−even effect observed in the molecularly resolved STM images of BP3 and BP4, therefore, confirms the pronounced influence of the spacer chain on the structure of these biphenyl-based SAMs.
ISSN:0743-7463
1520-5827
DOI:10.1021/la030165w