Polystyrene Beads as Probes of the Surface-Enhanced Raman Scattering Response Characteristics of Silver Nanorod Arrays

Abstract

Polystyrene microspheres were used to interrogate the surface-enhanced Raman scattering (SERS) response of silver nanorod (AgNR) array substrates. It has been suggested that enhancement between nanorods is significantly greater than that at the top due to contributing electromagnetic fields from each nanostructure. To test this theory, two different sized fluorescent polystyrene microspheres were used. The SERS intensity of beads small enough to fit within the array was compared with that of larger beads confined to rest on top of the array. Location of the beads within the array was established using optical fluorescence and scanning electron microscopy. The findings presented herein suggest that evaporation of the sample produces a nonuniform distribution of scatterers across the AgNR array and that the enhancement found for beads located on top of the AgNRs was significantly greater than that for beads located within the array.

Ordered array of Ag semishells on different diameter monolayer polystyrene colloidal crystals: An ultrasensitive and reproducible SERS substrate

“…The EM mechanism is recognized as the largest contribution4. Generally speaking, the EM mechanism is owing to the enhanced local electric field that results in a significant increase in the cross section of the Raman scattering56. The enormous enhancement of SERS is mainly derived from the “hot spots” on the metal surfaces78.…”

Unveiling practical considerations for reliable and standardized SERS measurements: lessons from a comprehensive review of oblique angle deposition-fabricated silver nanorod array substrates

“…Alternatively, Marotta and Bottomley conducted an experiment utilizing polystyrene (PS) beads of different sizes as Raman probes to demonstrate the significance of Ag nanorod tips in enhancing the Raman signal. 149 They dispensed 5 μL aliquots of 2 × 10 10 ml −1 20 nm-diameter PS beads and 2 × 10 7 ml −1 200 nm-diameter PS beads onto the AgNR wells with identical areas. Considering the geometry of AgNR substrates, the 20 nm PS beads were distributed between the Ag nanorods (Fig.…”