Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate

Sensors

卷:16

Wamadeva Balachandran¹  Krishna Burugapalli¹  Shavini Wijesuriya¹  Ruth Mackay¹  Godwin Chukwuebuka Ajaezi² 

[1] Biomedical Engineering Theme, Institute for Environment, Health and Societies, Brunel University London, Uxbridge UB8 3PH, UK;

[2] Department of Mechanical, Aerospace and Civil Engineering, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH, UK;

关键词: SERS substrate;    chemical etching;    solid silver;    surface roughness;    514 nm and 1064 nm Raman;   

DOI  :  10.3390/s16101742

来源: DOAJ

【 摘 要 】

Surface-enhanced Raman spectroscopy (SERS) substrates manufactured using complex nano-patterning techniques have become the norm. However, their cost of manufacture makes them unaffordable to incorporate into most biosensors. The technique shown in this paper is low-cost, reliable and highly sensitive. Chemical etching of solid Ag metal was used to produce simple, yet robust SERS substrates with broadband characteristics. Etching with ammonium hydroxide (NH4OH) and nitric acid (HNO3) helped obtain roughened Ag SERS substrates. Scanning electron microscopy (SEM) and interferometry were used to visualize and quantify surface roughness. Flattened Ag wires had inherent, but non-uniform roughness having peaks and valleys in the microscale. NH4OH treatment removed dirt and smoothened the surface, while HNO3 treatment produced a flake-like morphology with visibly more surface roughness features on Ag metal. SERS efficacy was tested using 4-methylbenzenethiol (MBT). The best SERS enhancement for 1 mM MBT was observed for Ag metal etched for 30 s in NH4OH followed by 10 s in HNO3. Further, MBT could be quantified with detection limits of 1 pM and 100 µM, respectively, using 514 nm and 1064 nm Raman spectrometers. Thus, a rapid and less energy intensive method for producing solid Ag SERS substrate and its efficacy in analyte sensing was demonstrated.

【 授权许可】

Unknown