Sensitive and Reproducible Gold SERS Sensor Based on Interference Lithography and Electrophoretic Deposition

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool due to its label-free detection ability and superior sensitivity, which enable the detection of single molecules. Since its sensitivity is highly dependent on localized surface plasmon resonance, various methods have been applied for electric field-enhanced metal nanostructures. Despite the intensive research on practical applications of SERS, fabricating a sensitive and reproducible SERS sensor using a simple and low-cost process remains a challenge. Here, we report a simple strategy to produce a large-scale gold nanoparticle array based on laser interference lithography and the electrophoretic deposition of gold nanoparticles, generated through a pulsed laser ablation in liquid process. The fabricated gold nanoparticle array produced a sensitive, reproducible SERS signal, which allowed Rhodamine 6G to be detected at a concentration as low as 10−8 M, with an enhancement factor of 1.25 × 105. This advantageous fabrication strategy is expected to enable practical SERS applications.

Hybrid Au/Si Disk-Shaped Nanoresonators on Gold Film for Amplified SERS Chemical Sensing

“…Thus, the design of nanostructures to achieve high enhancement factors in the research domain of SERS is a very important point in order to increase the sensitivity of the biological and chemical sensing. Modern micro/nanofabrication tools such as focused ion-beam lithography [7], electron-beam lithography [8,9,10,11], X-ray, deep UV, UV, and interference lithographies [12,13,14,15,16] favor the numerous designs of SERS substrates with an accuracy control over the shape and spatial distribution of nanostructures. Furthermore, some low cost techniques of fabrication as nanoimprint lithography (NIL) [17,18] and nanosphere lithography (NSL) [19,20,21,22] may enable the realization of these SERS substrates.…”

Efficient Capture and Raman Analysis of Circulating Tumor Cells by Nano-Undulated AgNPs-rGO Composite SERS Substrates

“…In Figure 2 e, the size distribution of the AgNPs showed a median nanoparticle size of 33 nm in the unit area (1 μm × 1 μm) utilizing ImageJ software. This nanostructure based on the AgNPs, which had a few tens of nm sized diameter and roughness with a sub-10 nm nanogap, is well suited for the high enhancement of the Raman signal [ 37 , 39 , 40 ]. The strong electromagnetic fields produced by the localized surface plasmon resonances at the surface of the AgNPs were a major mechanism of SERS, which showed that electromagnetic mechanism (EM) and hot spots generated from the narrow nanogaps near the AgNPs could be expected to greatly increase the SERS signals of the cells.…”

Calligraphed Selective Plasmonic Arrays on Paper Platforms for Complementary Dual Optical “ON/OFF Switch” Sensing

“…As a result, the negative PSS-coated AuBPs line ( Figure 3 a, red spectrum) and negative PSS-coated AuNRs line ( Figure 3 e—red spectrum) were able to electrostatically capture and detect the cationic R6G molecules demonstrated by the assignment of their characteristic vibrational Raman bands corresponding to located at 610 cm −1 (C–C–C ring in-plane vibration), 773 cm −1 (C–H out-of-plane bending), 1183 cm −1 (C–H and N–H bending of xanthene ring), 1360/1507/1648 cm −1 (aromatic C–C stretching) [ 35 , 36 ], and summarized also in Table 1 .…”

“…The Raman and fluorescence spectra collected from all charge-selective calligraphed plasmonic lines exposed to cationic R6G and anionic RB analytes are presented in Figure 3, revealing-as a first observation-that different active domains were effective at detecting different charged molecules. As a result, the negative PSS-coated AuBPs line (Figure 3a, red spectrum) and negative PSS-coated AuNRs line (Figure 3e-red spectrum) were able to electrostatically capture and detect the cationic R6G molecules demonstrated by the assignment of their characteristic vibrational Raman bands corresponding to located at 610 cm −1 (C-C-C ring in-plane vibration), 773 cm −1 (C-H out-of-plane bending), 1183 cm −1 (C-H and N-H bending of xanthene ring), 1360/1507/1648 cm −1 (aromatic C-C stretching) [35,36], and summarized also in Table 1. Table 1.…”