Self-Assembly of Silver Nanowire Films for Surface-Enhanced Raman Scattering Applications

Abstract

The development of SERS detection technology is challenged by the difficulty in obtaining SERS active substrates that are easily prepared, highly sensitive, and reliable. Many high-quality hotspot structures exist in aligned Ag nanowires (NWs) arrays. This study used a simple self-assembly method with a liquid surface to prepare a highly aligned AgNW array film to form a sensitive and reliable SERS substrate. To estimate the signal reproducibility of the AgNW substrate, the RSD of SERS intensity of 1.0 × 10−10 M Rhodamine 6G (R6G) in an aqueous solution at 1364 cm−1 was calculated to be as low as 4.7%. The detection ability of the AgNW substrate was close to the single molecule level, and even the R6G signal of 1.0 × 10−16 M R6G could be detected with a resonance enhancement factor (EF) as high as 6.12 × 1011 under 532 nm laser excitation. The EF without the resonance effect was 2.35 × 106 using 633 nm laser excitation. FDTD simulations have confirmed that the uniform distribution of hot spots inside the aligned AgNW substrate amplifies the SERS signal.