High-Resolution Distance Dependence Interrogation of Scanning Ion Conductance Microscopic Tip-Enhanced Raman Spectroscopy Enabled by Two-Dimensional Molybdenum Disulfide Substrates.

He, Xing; Tareq, Abu Montakim; Qi, Kai; Conti, Ylli; Tung, Vincent; Chiang, Naihao · Nano Lett · 2024

basic_science · Level V

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Abstract

Scanning ion conductance microscopy (SICM) is a powerful surface imaging tool used in the electrolytic environment. Tip-enhanced Raman spectroscopy (TERS) can give more information in addition to the morphology provided by the SICM by utilizing label-free Raman spectroscopy aided by the localized plasmonic enhancement from the metal-coated probes. In this study, the integration of SICM with TERS is demonstrated through employing a silver-coated plasmonic nanopipette. Leveraging a two-dimensional (2D) molybdenum disulfide (MoS<sub>2</sub>) as a model system, the SICM-TERS enhancement factor was estimated to be ∼10<sup>5</sup>, supported by finite-difference time-domain (FDTD) simulation. Moreover, the subnanometer distance dependence SICM-TERS study reveals the tensile stress and structural changes caused by the nanopipette. These findings illustrate the potential of SICM-TERS for providing comprehensive morphological and chemical insights into electrolytic environments, paving the way for future investigations of electrocatalytic and biological systems.