A stable, ultrasensitive and flexible substrate integrated from 1D Ag/α-Fe₂O₃/SiO₂ fibers for practical surface-enhanced Raman scattering detection

Conventionally, the surface-enhanced Raman spectroscopy (SERS) measurement is performed by dispersing noble metal nanoparticles onto the target sample directly or assembling noble metal nanoparticles onto a micro-sized substrate. Despite it is flourishing, this method is not adequate for various samples, mainly limited by either a defined confinement of the test position or the complex extraction process of the target sample on the irregularly shaped surface, besides the costive materials, complex and uncontrollable fabricating processes. Herein, we demonstrate that the α-Fe₂O₃ thin film is decorated with Ag nanoparticles constructed on SiO₂ fibers as a flexible SERS-active substrate, which yields a functional optical enhancement of the signal at 532 nm laser excitation. It shows a high enhancement factor of 4.71 × 10⁵, ultrahigh sensitivity of 10⁻¹⁵ M, and excellent signal stability with a relative standard deviation (RSD) of 1.22% and reproducibility with a RSD of 0.258%.