Magnetic-plasmonic Ni nanotubes covered with gold for improvement of SERS analysis
Ilya V. Korolkov, Alena Shumskaya, Аrtem L. Kozlovskiy, Malik E. Kaliyekperov, Lana I. Lissovskaya, Maxim V. Zdorovets
Abstract
The paper describes the synthesis of substrate for surface enhanced Raman spectroscopy (SERS) based on magnetic nickel nanotubes (Ni NTs). For the success application of Ni NTs in quantitative SERS analysis of organic molecules by the example of Rhodamine 6G (R6G), electroless deposition of gold (I) on Ni NTs in alkali media was performed. The purity and uniformity of the gold layer has been proven by methods of XRD , SEM-EDX, XPS and FTIR analysis. The magnetic properties of the obtained magnetic Ni-Au NTs measured by VMS did not change compared to the initial Ni nanotubes. The efficiency of substrates with Ni-Au NTs is determined by the optical properties of the substrate (the position of the plasmon resonance peak). The substrates with scattered nanotubes having a plasmon resonance position at 530 nm are the most effective for use in SERS when using a laser with a wavelength of 532 nm, as exemplified by the spectra of Radomin 6G. SERS analysis of R6G using Ni-Au NTs in concentration range from 10 −3 to 10 −8 led to average enhancement factor of 8∙10 5 .