Hybrid SERS substrate based on cotton swab for sensitive detection of organic molecules

Abstract

For the last two decades, the development of substrates for Surface Enhanced Raman Spectroscopy (SERS) has been continuously pushed for better performances. In this research, we designed SERS substrates with better detection capability and more efficient sample collection. In particular, morphology-controlled Ag nanoparticles were deposited onto cotton swab (cotton Q-tip), followed by a thin cover layer of graphene oxide by the dip-coating method. The graphene oxide overlay was expected to not only protect Ag nanoparticles from degradation by the environment but also contribute to sample adsorption and signal enhancement. To demonstrate the performance of the SERS substrates, different concentrations of Rhodamine B as low as 10–10 M were successfully detected and the enhancement factors were estimated to be 3 × 1010–5 × 1010. It is our expectation that these cotton swab-based substrates will contribute to our ongoing efforts toward low-cost, high-efficiency and durable SERS substrate.