Amine species on self-assembled monolayers of omega-aminothiolates on gold as identified by XPS and NEXAFS spectroscopy

作者：Dietrich Paul M; Graf Nora; Gross Thomas; Lippitz Andreas; Krakert Simone; Schuepbach Bjoern; Terfort Andreas; Unger Wolfgang E S^*

来源：Surface and Interface Analysis, 2010, 42(6-7): 1184-1187.

DOI：10.1002/sia.3224

• self-assembled monolayer
• amines
• XPS
• NEXAFS
• surface analysis

Functionalised surfaces are of interest in many fields, e. g. in biomedicine, materials science and molecular electronics. In this study a series of self-assembled aliphatic and aromatic monolayers on gold substrates with terminal amino groups was investigated. Four different thiol molecules were used: aliphatic 11-aminoundecane-1-thiol (AUDT), aromatic 4-aminobenzenethiol (ABT) and aromatic omega-amino thiols with an alkyl spacer as 4-aminophenylbutane-1-thiol (APBT) and 3-(4 ''-amino-1,1':4',1 ''-terphenyl-4-yl)propane-1-thiol (ATPT). Evaluation of N 1s XPS data revealed that on the aromatic self-assembled monolayers (SAMs) amino groups exist preferentially as primary amines, whereas on the aliphatic SAM protonated and/or hydrogen-bonded amines are the major species. This result is crosschecked by N K edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy and can be rationalised by the different basicity of aliphatic and aromatic amines.

• 出版日期2010-7