SERS Sensing Research Articles

SERS Sensing Using Graphene-Covered Silver Nanoparticles and Metamaterials for the Detection of Thiram in Soil

Multilayer hyperbolic metamaterial (HMM)-based SERS substrates have received special consideration because they accommodate various propagation modes such as surface plasmonic polaritons (SPP). However, the SPP modes are difficult to generate in HMM due to their weak electric field enhancement. In this article, we designed novel SERS substrates consisting of graphene-covered AgNPs and HMM. The graphene-covered AgNPs work as an external coupling structure for hyperbolic metamaterials due to this structure exhibiting significant plasmonic effects as well as unique optical features. The localized surface plasmonic resonance (LSPR) of the graphene-covered AgNPs excited the SPP and thus formed a strong hot spot zone in the nanogap area of the graphene. The Raman experiment was performed using rhodamine 6G (R6G) and crystal violet (CV), which showed high stability and a maximum enhancement factor of 2.12 × 108. The COMSOL simulation further clarified that enhanced SERS performance was due to the presence of monolayer graphene and provided an atomically flat surface for organic molecules in a more controllable manner. Interestingly, the proposed SERS structure carries out quantitative detection of thiram in soil and can satisfy the basic environmental need for pesticide residue in the soil.

Sers Sensing Using Graphene-Covered Silver Nanoparticles and Metamaterials for Detection of Thiram

Sers Sensing Using Graphene-Covered Silver Nanoparticles and Metamaterials for Detection of Thiram

Environmental-Friendly Etchant of in Situ Plasmon-Activated Water for Improvement of Sers Sensing on Pesticides

Environmental-Friendly Etchant of in Situ Plasmon-Activated Water for Improvement of Sers Sensing on Pesticides

Deposition of Nanostructured Ag Films on Silicon Wafers by Electrochemical/Electrophoretic Deposition for Electrochemical and SERS Sensing

Electrolysis of ultrapure water in a two-electrode cell with silver anode and conductive substrate (Si wafer) as a cathode leads to the formation of nanostructured silver layers deposited on cathode. In the process, the silver anode is electrochemically dissolved to silver cations, which react with water (or OH• radicals derived from water electrolysis) forming silver oxide nanoparticles, which fill the interelectrode space by electrophoretic movement, diffusion and convection induced by temperature effects of electrolysis. During the process the silver oxide nanoparticles are partially transformed into silver nanoparticles. On the cathode, silver cations and silver / silver oxide nanoparticles undergo reduction to form nanostructured silver film. The results of the present study open a new, extremely simple and ultra-low cost way to prepare nanostructured silver films on conducting and semiconducting substrates. The prepared nanosilver coated silicon substrates exhibit high performances as amperometric sensors for hydrogen peroxide and also as SERS substrates.

Triangular Elastomeric Stamps for Optical Applications: Near‐Field Phase Shift Photolithography, 3D Proximity Field Patterning, Embossed Antireflective Coatings, and SERS Sensing

AbstractThe use of a decal transfer lithography technique to fabricate elastomeric stamps with triangular cross‐sections, specifically triangular prisms and cones, is described. These stamps are used in demonstrations for several prototypical optical applications, including the fabrication of multiheight 3D photoresist patterns with near zero‐width features using near‐field phase shift lithography, fabrication of periodic porous polymer structures by maskless proximity field nanopatterning, embossing thin‐film antireflection coatings for improved device performance, and efficient fabrication of substrates for surface‐enhanced Raman spectroscopic sensing. The applications illustrate the utility of the triangular poly(dimethylsiloxane) decals for a wide variety of optics‐centric applications, particularly those that exploit the ability of the designed geometries and materials combinations to manipulate light–matter interactions in a predictable and controllable manner.