Hydrophobic multiscale cavities for high-performance and self-cleaning surface-enhanced Raman spectroscopy (SERS) sensing

Abstract

Cavity array, with excellent optical capture capability, has received increasing attention for the surface-enhanced Raman spectroscopy (SERS)-active substrates. Here, we proposed molybdenum disulfide (MoS2) nanocavities growing on pyramid Si (PSi) composed of in situ reduced Au nanoparticles (AuNPs), which can form the multiscale cavities (MSCs), and is facile for the couple of the plasmon. We demonstrated that the PSi/MoS2/Au MSCs can serve as highly sensitive, uniform, and stable SERS substrates for rhodamine 6G (R6G), crystal violet, and adenosine triphosphate detection, benefiting from the synergistic effect of the enhanced light trapping and the effective plasmonic couple. The couple of the plasmon in the MSCs is evidently proved by finite-difference time domain simulation, showing the strong electromagnetic field is located around the cavity wall. Moreover, the excellent hydrophobicity of the PSi/MoS2/AuNPs substrate endows it with the ability for the directional monitoring of organic pollutant in a mixture of oil and water. Finally, we demonstrated the MSCs with outstanding photocatalytic performance could achieve the renewable utilization by self-cleaning, which was attributed to the fast electron transfer and effective light absorption. The proposed PSi/MoS2/AuNPs MSC represents a robust mean using the plasmonic metal/semiconductor heterostructure for high-performance SERS sensors and photodegradation.

Hierarchically Assembled Plasmonic Metal-Dielectric-Metal Hybrid Nano-Architectures for High-Sensitivity SERS Detection

“…The comparison of the SERS performance of different SERS-active substrates with a 10 −6 M R6G concentration is demonstrated in Figure 4a, and the corresponding SERS enhancement is summarized in terms of Raman peak intensity in Figure 4b. Several of the most prominent Raman peaks of R6G are observed at the wavenumbers of 612, 776, 1185, 1310, 1363, 1506, 1574, and 1650 cm −1 , which are consistent with the characteristic peaks of R6G reported in the literature [43,44]. The band assignment of all the Raman peaks of R6G is also summarized in Table S1.…”

Surface-Enhanced Raman Scattering on Silver Sinusoidal Nanograting: Impact of Interactions of Grating-Coupled Surface Plasmon Polaritons

“…SERS, particularly, allows for highly sensitive detection and specific identification of analytes, has been extensively employed in multiple applications including trace molecules detection [8,9] , biosensors [10,11] , food security [12,13] , and environment safety [14,15] . Metallic nano-gratings [16,17] , in particular, experience large-area uniform electromagnetic enhancement [18,19] , which increases the chances for analyte detection via SERS spectroscopy [19][20][21] . Their properties are connected to surface plasmon polariton (SPP), whose resonance wavelength depends on the geometrical parameters of the nanograting, the incident light and the surrounding medium [7] .…”

Composite Structure of Ag Colloidal Particles and Au Sinusoidal Nanograting with Large-Scale Ultra-High Field Enhancement for SERS Detection

“…Surface-enhanced Raman spectroscopy (SERS), as a 'chemical fingerprint' of the target materials, is a sensitive and reliable detection method extensively employed in biosensors [1,2], food security [3,4], and environment safety [5,6]. Considerable efforts have been made to develop the SERS substrate, including fabricating and using a range of structures and materials [7,8]. In terms of conventional two-dimensional SERS substrates, the enhanced Raman signal usually relies on the "hot spots" generated by the LSP resonance between nanoparticles [9,10].…”