Highly ordered TiO₂ Nanotubes decorated with plasmonic silver nanoparticles (TiO₂/Ag) for ultra-sensitive SERS detection of textile dye contaminant Rhodamine 6 G

Abstract

We report a susceptible, ultrafast, molecular fingerprint-specific detection tool of analytes at an extreme trace concentration using surface-enhanced Raman spectroscopy (SERS). Highly ordered TiO2 Nanotubes (NT) modified with plasmonic Ag nanoparticles (Ag) are fabricated by wet chemical strategy. TiO2/Ag nanostructures could benefit the SERS mechanism arising from the effects of both the charge transfer process within TiO2/Ag/analyte and the enhancement in the electromagnetic field by the twining of plasmonic Ag nanoparticles with the construction of semiconductor/plasmonic bi-component system (TiO2/Ag). To achieve a better density of Ag NPs on TiO2 nanotubes, the photoinduction process irradiation time was varied from 10 min to 40 min. The prepared bicomponent SERS system was validated for its structural and morphological properties. SERS optimization studies were analyzed with the probe molecule Rhodamine 6 G (R6G) with an initial concentration of 10−6M. The highest SERS enhancement was notified with TiO2/Ag20 min for R6G sensing. The fabricated optical sensor reproducibility in signal detection was scrutinized with Raman mapping studies and statistically validated by low RSD values of 9.8%. Furthermore, their detectability was gauged with low concentration detection of R6G down to Pico-molar levels (10−12M). Synergistic effects of both CT and EM contributed to SERS enhancement to trace and detected pico-levels of R6G by the fabricated bicomponent semiconductor/ plasmonic heterostructure system (TiO2/Ag 20 min).