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Nanoscale Chemical Imaging of Interfacial Monolayers by Tip‐Enhanced Raman Spectroscopy
Author(s) -
Shao Feng,
Müller Vivian,
Zhang Yao,
Schlüter A. Dieter,
Zenobi Renato
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201703800
Subject(s) - monolayer , raman spectroscopy , nanoscopic scale , density functional theory , stacking , materials science , chemical physics , intermolecular force , spectroscopy , molecule , nanotechnology , molecular physics , chemistry , computational chemistry , optics , organic chemistry , physics , quantum mechanics
We report an investigation of interfacial fluorinated hydrocarbon (carboxylic‐fantrip) monolayers by nanoscale imaging using tip‐enhanced Raman spectroscopy (TERS) and density functional theory (DFT) calculations. By comparing TERS images of a sub‐monolayer prepared by spin‐coating and a π–π‐stacked monolayer on Au(111) in which the molecular orientation is confined, specific Raman peaks shift and line widths narrow in the transferred LB monolayer. Based on DFT calculations that take into account dispersion corrections and surface selection rules, these specific effects are proposed to originate from π–π stacking and molecular orientation restriction. TERS shows the possibility to distinguish between a random and locked orientation with a spatial resolution of less than 10 nm. This work combines experimental TERS imaging with theoretical DFT calculations and opens up the possibility of studying molecular orientations and intermolecular interaction at the nanoscale and molecular level.