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In this study, a detailed analysis on the surface‐enhanced Raman scattering of 1,4‐Benzenedithiol adsorbed on gold/graphene cluster is presented by density functional theory calculations. Results indicate that changing graphene type including perfect graphene, monovacancy graphene, B/N‐doped grapheme, and graphene oxide enables modulation of interaction between molecule, gold, and graphene cluster. Calculated Raman spectra of surface complexes are discussed considering chemical enhancement for graphene‐based surface‐enhanced Raman scattering study, which shows dependence on graphene types, which is related to several influence factors from electronic structure to excitation properties. [ABSTRACT FROM AUTHOR]

Novel surface-enhanced Raman scattering (SERS) substrates with stable and recyclable properties have been prepared by assembling gold nanoparticles-loaded PET (AuNPs/PET) nanocomposite superhydrophobic surfaces. After a physical vapor deposition process, the AuNPs/PET surfaces with vast plasmonic “hot spots” showed superhydrophobic properties, and it can hold target molecules droplets for rapid SERS detection. From blown off droplets and rinsed substrates with water after detection, we found that no probe molecules remained on the surfaces from Raman spectra. The prepared substrates were not contaminated in the detection process. Furthermore, the new SERS substrates were used for rapidly detecting droplets of crystal violet (CV) and the lowest detection concentration was about 1×10−9 M. The as-prepared AuNPs/PET substrates also have good performance in terms of reproducibility and recyclability. The AuNPs-loaded PET (AuNPs/PET) nanocomposite superhydrophobic surfaces were fabricated as stable and recyclable SERS substrates. The AuNPs/PET surfaces with hydrophobic property can hold target molecules droplets for rapid SERS detection. Blown off droplets and immediately rinsed the substrates once with water after detection, no probe molecules were found remained on the surfaces from Raman spectra. The prepared substrates will not be contaminated in the detection process. [ABSTRACT FROM AUTHOR]

Abstract: MoS2, a novel inorganic graphene analogues with typical two‐dimensional structure, has attracted increasing interest in various fields. MoS2‐based hybrid plasmonic structures have been extensively investigated as higher quality surface enhanced Raman scattering (SERS) substrates. Herein, we have designed a three‐dimensional (3D) MoS2 nanospheres (NSs) based hybrid nanostructure as SERS sensor by decorating Au nanoparticles (NPs) on the surface of 3D MoS2‐NSs (3D MoS2‐NS@Au‐NPs). 3D MoS2‐NSs acts as (a) a stable scaffold for Au NPs decoration via microwave‐irradiation hydrothermal process, (b) a chemical mechanism source for Raman enhancement, and (c) a 3D spatial structure for generation of more effective hot spots due to Au coupling effect and supply larger surface area for adsorbing probe molecules. The 3D MoS2‐NS@Au‐NPs hybrid structure exhibits 56‐fold improvement on enhancement factor compared to two‐dimensional MoS2‐NST@Au‐NPs hybrid structures. SERS performance was easily and effectively optimized with the tuning of the density and sizes of Au NPs. The optimized 3D MoS2‐NS@Au‐NPs was applied as SERS sensor for melamine detection in milk. Quantitative detection was realized in the range of 1 ppb–10 ppm with a linear coefficient of .997. Excellent sensitivity of 1 ppb and uniformity of 10.12% relative standard deviation was achieved, which could meet the demand for melamine detection as prescribed by the U.S. Food and Drug Administration. [ABSTRACT FROM AUTHOR]

A new, feasible, and highly efficient platform was developed using self-assembly of (3-aminopropyl) diethoxymethylsilane (ATES) to create metallic oxide-based noble metal nanoparticle hybrid materials. The ex situ approach for fabricating 1D MoO3-nanowires (MoO3-NWs) or ZnO-nanorods (ZnO-NRs) @Au-nanoparticles (Au-NPs) hybrid surface-enhanced Raman scattering (SERS) substrates not only provides a simple route for the decoration of noble metal nanoparticle on metallic oxide nanomaterials, but also realizes the controllable assembly/co-assembly of pre-synthesized nanoparticles with distinctively different sizes, compositions, shapes, and properties. Control over the self-assembly synthesis for morphology and SERS activity was demonstrated by several parameters: (i) coupling agent of ATES, (ii) ATES content, (iii) Au-NPs content, (iv) Au-NP sizes, and (v) other metallic oxide such as ZnO-NRs. The finite difference time domain (FDTD) method was employed to visualize the enhancement mechanism distribution of the hybrid substrate. Furthermore, the optimized MoO3-NW@Au-NPs SERS substrate manifests high SERS sensitivity to melamine with a limit of detection (LOD) of 0.1 ppb (0.08 nM) and excellent uniformity (RSD = 9.26%). The LOD was much lower than the maximal residue limit (MRL) of 2.5 ppm in food prescribed by the US Food and Drug Administration (FDA). [ABSTRACT FROM AUTHOR]

Gold nanorods (Au NRs)/Ti 3 C 2 T x composites were prepared by self-assembly method as surface enhanced Raman scattering (SERS) substrates. Due to strong electrostatic interaction, Au NRs are evenly arranged on the surface of Ti 3 C 2 T x nanosheets, forming rich SERS hotspots. Au NRs/Ti 3 C 2 T x have high sensitivity and good reproducibility for the determination of organic dyes such as rhodamine 6G, crystal violet and malachite green. The detection limits were 1 × 10−13, 1 × 10−13 and 1 × 10−12 M, respectively. The relative standard deviations of samples in 40 areas were 4.57 %, 2.79 % and 3.47 %, respectively. The synthesized SERS substrate is sensitive to adenine. For adenine molecules in the range of 1 × 10−5–1 × 10−9 M, SERS results show that the peak intensity is linear with adenine molecular concentration, and the detection limit can be as low as 1 × 10−9 M. In addition, adenine in aqueous solution has good anti-interference ability to other nucleic acids with similar structure, such as guanine, cytosine and thymine. Therefore, Au NRs/Ti 3 C 2 T x are expected to become a potential substrate for unmarked, rapid and sensitive SERS detection of adenine in the field of bioanalysis. • A SERS substrate based on gold nanorods (Au NRs)/Ti 3 C 2 T x composites is proposed. • The Au NRs/Ti 3 C 2 T x substrate has high SERS sensitivity for adenine molecules. • It also has high sensitivity and good reproducibility in the determination of common organic dyes. [ABSTRACT FROM AUTHOR]