Subnanometer-resolved chemical imaging via multivariate analysis of tip-enhanced Raman maps

• 来源期刊: 光：科学与应用（英文版）
• 关键词: chemical imaging hyperspectral imaging multivariate analysis nanoimaging tip-enhanced Raman spectroscopy
• 年，卷（期）: 2017,（4）
• 页码范围: 163-170
• 页数: 8页
• 语种: 英文
• DOI: 10.1038/lsa.2017.98

摘要

Tip-enhanced Raman spectroscopy (TERS) is a powerful surface analysis technique that can provide subnanometer-resolved images of nanostructures with site-specific chemical fingerprints.However,due to the limitation of weak Raman signals and the resultant difficulty in achieving TERS imaging with good signal-to-noise ratios (SNRs),the conventional single-peak analysis is unsuitable for distinguishing complex molecular architectures at the subnanometer scale.Here we demonstrate that the combination of subnanometer-resolved TERS imaging and advanced multivariate analysis can provide an unbiased panoramic view of the chemical identity and spatial distribution of different molecules on surfaces,yielding high-quality chemical images despite limited SNRs in individual pixel-level spectra.This methodology allows us to exploit the full power of TERS imaging and unambiguously distinguish between adjacent molecules with a resolution of ～ 0.4 nm,as well as to resolve submolecular features and the differences in molecular adsorption configurations.Our results provide a promising methodology that promotes TERS imaging as a routine analytical technique for the analysis of complex nanostructures on surfaces.