Tuning One Dimensional Plasmonic Gap at Nanometer Scale for Advanced SERS Detection

TL;DR

This paper presents a method to create thermally tunable nanogaps on flexible substrates, enabling dynamic control of SERS hotspots for highly sensitive molecular detection, including single-molecule levels.

Contribution

It introduces a novel approach for real-time, large-scale tunable nanogaps using thermally responsive materials, advancing SERS detection capabilities.

Findings

Achieved uniform, tunable nanogaps over large areas

Enhanced SERS signals with an enhancement factor over 10^7

Detected molecules at concentrations as low as 10^-12 M

Abstract

The hotspots, which are typically found in nanogaps between metal structures, are critical for the enhancement of the electromagnetic field. Surface-enhanced Raman scattering (SERS), a technique known for its exceptional sensitivity and molecular detection capability, relies on the creation of these hotspots within nanostructures, where localized surface plasmon resonance (LSPR) amplifies Raman signals. However, creating adjustable nanogaps on a large scale remains challenging, particularly for applications involving biomacromolecules of various sizes. The development of tunable plasmonic nanostructures on flexible substrates represents a significant advance in the creation and precise control of these hotspots. Our work introduces tunable nanogaps on flexible substrates, utilizing thermally responsive materials to allow real-time control of gap width for different molecule sizes. Through advanced nanofabrication techniques, we have achieved uniform, tunable nanogaps over large areas wafer scale, enabling dynamic modulation of SERS signals. This approach resulted in an enhancement factor of over 10^7, sufficient for single-molecule detection, with a detection limit as low as 10^-12 M. Our thermally tunable nanogaps provide a powerful tool for precise detection of molecules and offer significant advantages for a wide range of sensing and analytical applications