Direct Experimental Evidence of Hot Carrier-Driven Chemical Processes in Tip-Enhanced Raman Spectroscopy (TERS)

Journal Article · Thu Dec 26 00:00:00 EST 2019 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/acs.jpcc.9b12002· OSTI ID:1599167

Wang, Rui ^[1]; Li, Jingbai ^[2]; Rigor, Joel ^[3]; Large, Nicolas ^[3]; El-Khoury, Patrick Z. ^[4]; Rogachev, Andrey Yu. ^[2]; Kurouski, Dmitry ^[1]

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1. Texas A & M Univ., College Station, TX (United States)
2. Illinois Inst. of Technology, Chicago, IL (United States)
3. Univ. of Texas at San Antonio, TX (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Nanoscale localization of electromagnetic fields using metallic nanostructures can catalyze chemical reactions in their immediate vicinity. Local optical field confinement and enhancement is also exploited to attain single molecule detection sensitivity in surface and tip-enhanced Raman (TER) spectroscopy. In this work reported herein, we observe and investigate the sporadic formation of 4-nitrobenzenethiolate upon TER imaging of a 4-nitrobenzenethiol (4NBT) monolayer on Au(111). Density functional theory (DFT), finite-difference time-domain (FDTD), and finite element method (FEM) calculations together confirm that this chemical reaction does not occur as a result of thermal desorption of the molecule, which requires temperatures in excess of 2100 K at the tip-sample junction. Our combined experimental and theoretical analyses strongly suggest that the chemical transformations observed throughout the course of TERS mapping is not driven by plasmonic photothermal heating, but rather by plasmon-induced hot carriers.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: Governor’s University Research Initiative (GURI); US Army Research Office (ARO); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1599167
• Report Number(s): PNNL-SA--149743
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 3 Vol. 124; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Desorption
anions
gold
metals
raman spectroscopy