Surface-Enhanced Raman Scattering Sensors: A Comparative Study of Copper and Palladium Nanostructures for Nitrite Detection

Abstract

In scientific research, the search for cost-efficient and scalable functional materials for substantial and practical applications is necessary. Therefore, metallic materials at the nanoscale represent a rapidly growing area of research, especially as plasmonic materials in the field of surface-enhanced Raman scattering (SERS). In this study, the potential of copper nanowires (CuNWs) and palladium nanoparticles (PdNPs) as thin films on the porous silicon (PS) surface was investigated and compared. Their parameters as plasmonic SERS sensing materials were investigated by detecting sodium nitrite (NaNO2) molecules as the analyzing material. CuNWs and PdNPs were locally deposited on the PS substrate by the immersion method to synthesize Cu/PS and Pd/PS SERS sensors. The successful fabrication of these sensors was confirmed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FESEM), and Raman measurements. The results show that the nanostructures of the metallic thin films are evenly distributed on the PS surface and that hot spot areas have formed in between. The Raman peaks of NaNO2 were effectively detected even at extremely low concentration values. Therefore, CuNWs and PdNPs were integrated with PS in the SERS to improve the detection process. Excellent detection of (5×10-6) M NaNO2 concentration was achieved with the Cu/PS and Pd/PS SERS sensors with high amplification factors of (0.43×108) and (0.11×108), respectively.

Keywords

• plasmons
• cunws
• pdnps
• sers sensors
• nano2 detection