Ion beam modifications of plasmonic PET flexible SERS substrates using a table top accelerator

Ion beam modification induces significant surface alterations that are crucial for applications in Surface Enhanced Raman Spectroscopy (SERS). SERS, a highly sensitive analytical technique, amplifies weak Raman signals by increasing the effective Raman cross-section of target analytes. This study investigates the development of SERS substrates using ion beam-based surface modification on flexible polymer substrates. Gold (Au) thin films were thermally evaporated onto Polyethylene Terephthalate (PET) sheets and subsequently irradiated with 10 keV Ar⁺ ions at fluences of 1 × 10¹⁵, 3 × 10¹⁵, 1 × 10¹⁶, and 3 × 10¹⁶ ions/cm². The morphological changes in the films were characterized via Field Emission Scanning Electron Microscopy (FESEM). Both untreated and ion-irradiated films were assessed as SERS substrates for detecting Rhodamine B (RhB) dye at micro-molar (μM) and nano-molar (nM) concentrations. The findings emphasize the potential of ion-irradiated flexible polymer substrates in SERS applications. They demonstrate the crucial importance of surface engineering in improving the deposition of noble metals on the polymer surface, leading to enhanced sensing performance.