Rapid fabrication of self-assembled interfacial film decorated filter paper as an excellent surface-enhanced Raman scattering substrate

Abstract

An excellent paper-based SERS substrate was easily fabricated by utilizing interfacial films formed in the mixture of Ag colloid and CH₂Cl₂. This interfacial film coating method significantly improves the fabrication efficiency of SERS substrates. The substrate has a high coverage of silver nanoparticles (Ag NPs) and can be tailored to arbitrary shapes. The SERS substrate exhibits high sensitivity (EF ∼ 4 × 10⁷) and gives uniform SERS signals with a relative standard deviation (RSD) of 8.08% (spot-to-spot) and 8.65% (batch-to-batch) using 4-mercaptobenzoic acid (4-MBA) as a Raman probe. In addition, this SERS substrate with excellent stability can be stored for more than 30 days. The limit of detection was found to be 10⁻⁸ M for 4-MBA. In general, this SERS substrate is qualified for rapid and simple trace detection of various analytes.