One-step fabrication of fiber optic SERS sensors via spark ablation

Attila Kohut,Zsuzsanna Pápa,Gábor Galbács,Balázs Vajda,Judit Kopniczky,Zsolt Geretovszky,Viktória Horváth

doi:10.1088/1361-6528/ac0c41

Abstract

Spark ablation, a versatile, gas-phase physical nanoparticle synthesis method was employed to fabricate fiber-optic surface enhanced Raman scattering (SERS) sensors in a simple single-step process. We demonstrate that spark-generated silver nanoparticles can be simply deposited onto a fiber tip by means of a modified low-pressure inertial impactor, thus providing significant surface enhancement for fiber-based Raman measurements. The surface morphology of the produced sensors was characterized along with the estimation of the enhancement factor and the inter- and intra-experimental variation of the measured Raman spectrum as well as the investigation of the concentration dependence of the SERS signal. The electric field enhancement over the deposited silver nanostructure was simulated in order to facilitate the better understanding of the performance of the fabricated SERS sensors. A potential application in the continuous monitoring of a target molecule was demonstrated on a simple model system.

Highlights

Rapid development of optical fiber manufacturing technologies allowed the development of various fiber optic probes and measurement systems
The time of particle deposition was arbitrarily set to 10 min, after which the surface enhanced Raman scattering (SERS) performance of the fiber was tested along with the characterization of the fiber tip exposed to the aerosol stream
Please note that particles were always deposited onto a freshly cleaved surface. It can be seen in figure 2(A), that the reference spectrum measured with a bare fiber, without NPs on the surface does not exhibit any of the characteristic peaks of Rhodamine 6G (R6G)

Summary

Introduction

Rapid development of optical fiber manufacturing technologies allowed the development of various fiber optic probes and measurement systems. An optical fiber equipped with a SERS-active structure on one end allows for spatially separating the monitored environment from the monitoring personnel and instrumentation, while maintaining a sufficiently high sensitivity Such fiber optic SERS sensors have found many promising applications in the Nanotechnology 32 (2021) 395501 fields of biology, food science, detection of environmental pollutants, pharmaceutics or in vitro an in vivo biosensing [6,7,8]. In the present study we demonstrate that spark-generated Ag NPs can be deposited onto the tip of an optical fiber by using a modified low-pressure inertial impactor and SERS sensors can be fabricated in a facile and straightforward way, providing a reasonable platform for simple and low-cost Raman-based sensing applications. The potential applicability of the fabricated SERS sensors in the continuous monitoring and detection of a target molecule has been demonstrated on a simple model system

Methods

Results

Conclusion