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Gold nanonails for surface-enhanced infrared absorption.
Hang Yin1, Nannan Li, Yubing Si
1Henan Provincial Key Laboratory of Nanocomposites and Applications, Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006, China. baochengyang@infm.hhstu.edu.cn.
Nanoscale Horizons
|June 25, 2020
Summary
High-aspect-ratio gold nanonails and nanorods act as nanoantennas for surface-enhanced infrared absorption (SEIRA) spectroscopy. This advancement enables highly sensitive detection of molecules, crucial for diagnostics.
Area of Science:
- Plasmonics
- Nanotechnology
- Spectroscopy
Background:
- Surface-enhanced infrared absorption (SEIRA) dramatically amplifies molecular vibrational signals through plasmon-molecule interactions.
- High-aspect-ratio nanostructures are key for SEIRA, but physical fabrication methods limit their performance.
- Existing methods lead to damping and low densities, hindering practical applications.
Purpose of the Study:
- To develop and characterize novel high-aspect-ratio gold nanostructures for enhanced SEIRA performance.
- To investigate the tunability of plasmon resonance and SEIRA capabilities with varying aspect ratios.
- To demonstrate the application of these nanostructures in sensitive molecular detection.
Main Methods:
- Synthesis of high-aspect-ratio gold nanorods.
- Fabrication of gold nanonails via overgrowth on gold nanorods.
- Characterization of nanostructure aspect ratios and plasmon resonance wavelengths (1.6–8.3 μm).
- Evaluation of SEIRA performance using 4-aminothiophenol and l-cysteine.
- Numerical simulations to elucidate enhancement mechanisms.
Main Results:
- Tunable aspect ratios (∼10–60) achieved for both gold nanorods and nanonails.
- Plasmon resonance wavelengths tailored from ∼1.6 to ∼8.3 μm.
- Gold nanonails demonstrated superior SEIRA performance compared to nanorods.
- Successful detection of the biomolecule l-cysteine.
- Simulations confirmed experimental observations and revealed SEIRA enhancement mechanisms.
Conclusions:
- Colloidal high-aspect-ratio gold nanonails and nanorods serve as effective SEIRA nanoantennas.
- These nanostructures offer a pathway for highly sensitive molecular detection in diverse applications.
- The developed fabrication method overcomes limitations of previous physical methods.
