Surface-Enhanced Raman Spectroscopy To Probe Photoreaction Pathways and Kinetics of Isolated Reactants on Surfaces: Flat versus Curved Substrates

Autor: John L. Payton, Tze-Bin Song, Hong Ma, Yuxi Zhao, Yuebing Zheng, Lasse Jensen, Alex K.-Y. Jen, Paul S. Weiss, Yang Yang, Bala Krishna Pathem
Rok vydání: 2012
Předmět:
Zdroj: Nano Letters. 12:5362-5368
ISSN: 1530-6992
1530-6984
DOI: 10.1021/nl302750d
Popis: We identify and control the photoreaction paths of self-assembled monolayers (SAMs) of thiolate-linked anthracene phenylethynyl molecules on Au substrate surfaces, and study the effects of nanoscale morphology of substrates on regioselective photoreactions. Two types of morphologies, atomically flat and curved, are produced on Au surfaces by controlling substrate structure and metal deposition. We employ surface-enhanced Raman spectroscopy (SERS), combined with Raman mode analyses using density functional theory, to identify the different photoreaction paths and to track the photoreaction kinetics and efficiencies of molecules in monolayers. The SAMs on curved surfaces exhibit dramatically lower regioselective photoreaction kinetics and efficiencies than those on atomically flat surfaces. This result is attributed to the increased intermolecular distances and variable orientations on the curved surfaces. Better understanding of the morphological effects of substrates will enable control of nanoparticle functionalization in ligand exchange in targeted delivery of therapeutics and theranostics and in catalysis.
Databáze: OpenAIRE