The Prevalence of Anions at Plasmonic Nanojunctions: A Closer Look at p-Nitrothiophenol

• DOI: 10.1021/acs.jpclett.0c01006
• Publication Date: 2020-04-28T00:53:30Z
• Authors: Chih-Feng Wang; Brian T. O’Callahan; Dmitry Kurouski; Andrey Krayev; Patrick Z. El-Khoury
• Keywords: 01 natural sciences; 0104 chemical sciences

We revisit the reductive coupling of p-nitrothiophenol (NTP) to form dimercaptoazobenzene (DMAB), herein monitored through gap-mode tip-enhanced Raman spectroscopy (TERS) and nanoimaging. employ a plasmonic Au probe (100 nm diameter at its apex) illuminated with 633 laser source (50 μW/μm2 sample position) image an NTP-coated faceted silver nanoparticle (∼70 diameter). A detailed analysis recorded spectra reveals that anionic NTP species contribute spectral images, in addition more thoroughly described DMAB product. Notably, signatures anions are pronounced than those product under our present experimental conditions. Our results thus demonstrate their must be considered plasmon-enhanced optical images.