Raman enhancement properties of TiO2/Ag carbon fiber cloth using the ultraviolet-induced method: high sensitivity, flexible and reusable

Abstract

We report a low-cost fabrication strategy to prepare a large-area carbon fiber cloth (CFC) coated by Ag nanoparticles (AgNPs) as a flexible surface-enhanced Raman scattering substrate. AgNPs were deposited on a hydrophilized CFC by ultraviolet (UV) irradiation of AgNO3 solution, named UV-AgNPs@CFC. The UV irradiation duration and AgNO3 solution concentration can affect the AgNPs structure. SERS property is investigated using rhodamine 6 G (R6G) and crystal violet (CV) as standard analytes and the detection concentration level is down to 10−10 mol/L. The analytical enhancement factor can reach 1.22 × 109. Also, the substrate has remarkable stability and uniformity; the relative standard deviation (RSD) of the characteristic peak calculated at 611cm−1 is 14.4%. Additionally, the UV-AgNPs@CFC substrate can detect two different molecules simultaneously. Our flexible SERS substrate enables efficient molecular extraction and Raman measurements on the curved surface of apples. The detection concentration level for CV is down to 10−5 mol/L. Moreover, the electric field distribution of the hybrid structure is simulated by the finite difference time domain and COMSOL Multiphysics software, and the maximal electric field intensity is 25.7 V/m. Meanwhile, we deposited AgNPs on the TiO2 nanorods-modified CFC (TiO2-CFC) by UV irradiation. A reusable self-cleaning UV-AgNPs@TiO2-CFC substrate was fabricated.