Metal-free and flexible surface-enhanced Raman scattering substrate based on oxidized carbon cloth

Flexible surface-enhanced Raman scattering (SERS) substrates show great potential application in environmental, biological and technological sensors. However, most of flexible SERS substrates are designed based on depositing or embedding metal (Ag, Au, Cu) particles on or into polymer supports or woven fibers without SERS activity, which suffer from complex manipulation processes and high cost. In this work, oxidized carbon cloth fabricated by chemical oxidation of commercial carbon cloth used as a metal-free and highly flexible SERS substrate with detection of limit for Rhodamine 6G down to below 10(-8) M is reported. The SERS sensitivity of oxidized carbon cloth is improved by more than 3 order magnitude than untreated carbon cloth. By combining experimental analyses and theoretical calculations, it is proved that rich oxygen-containing functional groups on carbon cloth surface introduced by chemical oxidation leads to enhanced charge transfer (chemical enhancement) between oxidized carbon cloth and adsorbed molecules, which is responsible for the improved SERS performance. This work may pave the way for metal-free and flexible SERS substrate design and provides valuable insights for carbon-based SERS substrate. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This work presents a metal-free and highly flexible SERS substrate fabricated by chemical oxidation of commercial carbon cloth. The SERS sensitivity of the oxidized carbon cloth is significantly improved by more than 3 orders of magnitude compared to the untreated carbon cloth. The improved SERS performance is attributed to enhanced charge transfer between the oxidized carbon cloth and the adsorbed molecules due to the introduction of rich oxygen-containing functional groups by chemical oxidation. This study paves the way for the design of metal-free and flexible SERS substrates and provides valuable insights for carbon-based SERS substrates.