Conformational heterogeneity of molecules physisorbed on a gold surface at room temperature

A quantitative single-molecule tip-enhanced Raman spectroscopy (TERS) study at room temperature remained a challenge due to the rapid structural dynamics of molecules exposed to air. Here, we demonstrate the hyperspectral TERS imaging of single or a few brilliant cresyl blue (BCB) molecules at room...

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Bibliographic Details
Published in:Nature communications 2022-07, Vol.13 (1), p.4133-4133, Article 4133
Main Authors: Kang, Mingu, Kim, Hyunwoo, Oleiki, Elham, Koo, Yeonjeong, Lee, Hyeongwoo, Joo, Huitae, Choi, Jinseong, Eom, Taeyong, Lee, Geunsik, Suh, Yung Doug, Park, Kyoung-Duck
Format: Article
Language:English
Subjects:
639/624/400/1021
639/638/440/527/1821
Aluminum oxide
Chemical reactions
Contamination
Density functional theory
Dynamic structural analysis
Heterogeneity
Humanities and Social Sciences
multidisciplinary
Photobleaching
Raman spectroscopy
Robustness
Room temperature
Science
Science (multidisciplinary)
Spectroscopic analysis
Spectroscopy
Spectrum analysis
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Summary:A quantitative single-molecule tip-enhanced Raman spectroscopy (TERS) study at room temperature remained a challenge due to the rapid structural dynamics of molecules exposed to air. Here, we demonstrate the hyperspectral TERS imaging of single or a few brilliant cresyl blue (BCB) molecules at room temperature, along with quantitative spectral analyses. Robust chemical imaging is enabled by the freeze-frame approach using a thin Al 2 O 3 capping layer, which suppresses spectral diffusions and inhibits chemical reactions and contamination in air. For the molecules resolved spatially in the TERS image, a clear Raman peak variation up to 7.5 cm −1 is observed, which cannot be found in molecular ensembles. From density functional theory-based quantitative analyses of the varied TERS peaks, we reveal the conformational heterogeneity at the single-molecule level. This work provides a facile way to investigate the single-molecule properties in interacting media, expanding the scope of single-molecule vibrational spectroscopy studies. Tip-enhanced vibrational spectroscopy at room temperature is complicated by molecular conformational dynamics, photobleaching, contaminations, and chemical reactions in air. This study demonstrates that a sub-nm protective layer of Al 2 O 3 provides robust conditions for probing single-molecule conformations.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-022-31576-x