PDMS/TiO2/Ag hybrid substrate with intrinsic signal and clean surface for recyclable and quantitative SERS sensing

The acquisition of a robust plasmonic substrate with both appreciable molecule anchoring and quantitative detection features is a prerequisite for the reliable adhibition of surface-enhanced Raman scattering (SERS) technology. Herein, an innovative sophisticated SERS substrate was proposed by spin-coating titanium dioxide (TiO 2 ) onto a flexible polydimethylsiloxane (PDMS) film followed by the modification of triangular silver (Ag) nanoplates through in-situ reduction. The absence of organic surfactants during this process rendered the substrate great opportunity in effectively enriching molecules and the assembly of TiO 2 and Ag made it a reusable and sensitive SERS platform. After a recyclable monitoring of 4-aminothiophenol (4-ATP) with different concentrations was carried out by reusing the hybrid substrate for 8 cycles, a limit of detection as low as 1.58 × 10 −9 M was achieved. The distinctive intrinsic Raman signal from PDMS matrix was further verified to successfully correct the poor detection linearity by serving as internal standard and the coefficient of linear correlation (R 2 ) was improved from 0.967 to 0.997. In this regard, the as-prepared multifunctional PDMS/TiO 2 /Ag hybrid substrate with simulation-estimated electromagnetic “hot spots” exhibited remarkable quantitative recyclable detection performance.