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Elevating Surface-Enhanced Infrared Absorption with Quantum Mechanical Effects of Plasmonic Nanocavities
Guangyan Huang1, Kaizhen Liu1, Guangyi Shi1
1Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China.
Nano Letters
|July 22, 2022
Summary
Quantum effects in subnanometer plasmonic nanocavities enhance, not quench, infrared absorption signals. This quantum tunneling effect boosts surface-enhanced infrared absorption (SEIRA) for ultrasensitive molecular detection.
Area of Science:
- Nanophotonics
- Quantum Optics
- Surface Science
Background:
- Plasmonic nanocavities concentrate light for ultrasensitive applications.
- Quantum mechanical effects typically cause signal quenching at subnanometer gaps.
Purpose of the Study:
- To investigate quantum mechanical effects in subnanometer plasmonic nanocavities.
- To explore the impact of these effects on surface-enhanced infrared absorption (SEIRA).
Main Methods:
- Fabrication of plasmonic nanocavities using gold and cadmium oxide nanoparticles.
- Investigation of mid-infrared plasmonic resonances and SEIRA of alkanethiol monolayers.
- Analysis of nanocavity gap effects on plasmonic resonances and SEIRA signals.
Main Results:
- Plasmonic nanocavities with subnanometer gaps exhibited blue-shifted resonances.
- Quantum tunneling across subnanometer gaps significantly increased SEIRA signals.
- Demonstrated elevated SEIRA of alkanethiol monolayers.
Conclusions:
- Quantum mechanical effects can enhance SEIRA, contrary to typical quenching.
- Subnanometer plasmonic nanocavities offer a new route for optimizing SEIRA sensitivity.
- Quantum tunneling is key to enhanced field enhancement and detection.
