Metal-Organic Framework Coating for the Preservation of Silver Nanowire Surface-Enhanced Raman Scattering Platform

Ag nanostructures are investigated as efficient plasmonic platforms because of their superior optical properties. However, the easy corrosion of Ag surfaces by reaction with oxygen or sulfur in the atmosphere can seriously affect the optical properties of Ag nanostructures, limiting the stable operation of Ag platforms. Herein, it is reported that a metal-organic framework (MOF) enables an Ag nanowire (NW) surface-enhanced Raman scattering (SERS) platform to be corrosion resistant. A single Ag NW on a film (Ag-NOF), an effective SERS-active platform, is coated with the zeolitic imidazolate framework-8, and then the corrosion resistance of the Ag-NOF structures is examined under a variety of harsh environmental conditions. Interestingly, the MOF-coated Ag-NOF platforms are found to provide excellent oxidation and sulfidation resistance. With the MOF coating, the SERS signals of the Ag-NOF structures are well maintained under harsh conditions, while the signals are reduced without MOF coating. More importantly, it is clearly verified that the MOF coating preserves the DNA sensing performance of the Ag-NOF platform even after storage under several environmental conditions. Based on the results, it is anticipated that these MOF-coated Ag-NOF structures will be used as long-term stable SERS sensors for the detection of biological and chemical molecules.