Fabrication of sandwich structures of Ag/analyte/MoO₃ sea urchins for SERS detection of methylene blue dye molecules

Abstract

A SERS substrate in a sandwich configuration, noble metal/analyte/defect-rich metal oxide, is demonstrated for the detection of methylene blue (MB). The sandwich structure (Ag/MB/SUMoO3) is fabricated by physical vapour deposition of Ag nanoparticles over the MB analytes that are adsorbed on sea urchin MoO3 (SUMoO3). SUMoO3 are grown on a glass substrate by chemical bath deposition. The morphology of the fabricated sandwich structures shows serrated spikes of MoO3 from the core region decorated with strings of silver nanoparticles. The silver-decoration and the oxygen defects of SUMoO3 promote absorption in the visible region and facilitate charge transfer between MB and SUMoO3, which are beneficial for achieving superior SERS properties in this configuration compared to the contribution from individual components alone. The sandwich structure is able to detect the MB molecule up to 100 nM with an enhancement factor of 8.1×106. The relative standard deviation of SERS intensity for the 1618 cm-1 peak of MB across the substrate is 29.2%. The configuration offers stability to SERS substrate under ambient conditions. The combined effect of charge transfer, surface plasmon resonance, and MB resonance results in the improved SERS detection of MB molecules with the Ag/MB/SUMoO3 sandwich structure.

Design, Fabrication, and Applications of SERS Substrates for Food Safety Detection: Review

“…In the bottom-up approaches, the nanostructures can be done by chemical deposition [ 120 , 129 , 143 , 144 ], 3D printing [ 124 , 145 ], self-assembly particles [ 123 ], and chemical synthesis [ 126 , 130 , 131 , 132 , 133 , 134 , 135 ]. During the chemical deposition, controlling the size and the shape of the deposited nanostructures is a challenge.…”

Flower-like Ag-decked non-stoichiometric Bi2O3−x/rGO hybrid nanocomposite SERS substrates for an effective detection of Rhodamine 6G dye molecules

“…An EF of 8.1 × 10 6 with detection of a concentration as low as 100 nM was achieved. 20 Hence, the preparation of a SERS substrate composed of plasmonic Ag and a defect-rich metaloxide-decked rGO nanosheet could provide a SERS-active…”

“…An EF of 8.1 × 10 6 with detection of a concentration as low as 100 nM was achieved. 20 Hence, the preparation of a SERS substrate composed of plasmonic Ag and a defect-rich metal-oxide-decked rGO nanosheet could provide a SERS-active substrate with improved EF and sensing power. The semiconductor chosen to prepare the rGO-based nanohybrid was Bi 2 O 3 .…”