Surface-enhanced Raman imaging (SERI) as a technique for imaging molecular monolayers with chemical selectivity under ambient conditions
✍ Scribed by X. M. Yang; D. A. Tryk; K. Hashimoto; A. Fujishima
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 442 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
Surface-enhanced Raman imaging (SERI) has recently been developed as a surface imaging technique that is chemically selective, has monolayer sensitivity and can be used under ambient pressure conditions. At present, the resolution is 1-2 lm. A particularly interesting application is to image patterned self-assembled monolayers (SAMs). In the present work, the microcontact printing technique was used to prepare patterned SAMs composed of molecules with either a single type of terminal functional group OH, COOH or or two (NO 2 , NH 2 , C H 3 ) di †erent, sequentially assembled, molecules, each with its own terminal functional group (e.g. NH 2 /CH 3 , In the case of the SAM, it was found that the intense peak used for the imaging could NO 2 /NH 2 ).
NH 2 -terminated be assigned to the NxN stretching mode for an azobenzene-like species. The patterned SAMs were imaged using a micro-Raman system in the point-by-point imaging mode, after collection of full spectra at each point (ca. 1 s acquisition time). Evaporated silver Ðlms were used as SERS substrates ; these are characterized by intrinsic subsurface roughness in the 50-100 nm range, which provides sufficient enhancement for the SER imaging.