Novel Approaches in Tip-Enhanced Raman Spectroscopy: Accurate Measurement of Enhancement Factors and Pesticide Detection in Tip Dimer Configuration

Tip-enhanced Raman spectroscopy (TERS) allows the precise manipulation of a nanometric probe for surface chemical analysis by plasmon-based amplification of Raman signals; however, acknowledged procedures and materials for assessing the enhancement factor in different configurations are still lacking. In this work, we propose a technique for the standardization of TERS intensity measurements, by chemisorption of different organic Raman-active molecules on plasmonic probes, and compare it to the conventional procedures addressed to the same goals. In addition, by ideally considering TERS as a special case of surface-enhanced Raman (SERS) involving a single nanoparticle, we experimentally realized the three most common configurations in SERS: i. isolated particle, ii. single scattering probe on a surface, and iii. nanoparticle dimers. To achieve the latter in an accessible way with plasmonic probes, we established a fabrication procedure for a substrate presenting multiple nanometric tips, intended to be ea...