Quasi‐3D‐Structured Surface‐Enhanced Raman Scattering Substrates Based on Silver Nanoparticles/Mesoporous Silicon Hybrid

Abstract

The surface‐enhanced Raman scattering (SERS) is a powerful spectroscopic technique for ultrasensitive and selective biochemical detection due to its capability of providing the “fingerprint” of information of molecular structures at low concentrations. Herein, mesoporous silicon (MPSi)‐based nanocomposites containing silver nanoparticles (AgNPs) provide novel efficient substrates for the detection of molecules. The quasi‐3D‐structured SERS substrate is formed by introducing Ag into the MPSi hollow column‐shaped nanostructure. This SERS substrate uniquely combines the ability of metal surfaces to amplify Raman scattering signals with an enlarged surface area and the increasing light–matter interaction duration that generates large SERS signals for the detection of chemicals. The proposed SERS substrate is verified by detecting orange methylene in solutions at ultralow concentration in the range of 10−11–10−6 m with a linear‐dependent coefficient of R2 = 0.99922 and the SERS enhancement factor is achieved up to 1010. Moreover, the proposed platform can detect diphenylamine with ultralow concentration of 10−10 m and reliable reproducibility with an average relative stand deviation of 6.3%. The ability for MPSi substrate to detect target molecules at low concentrations helps pave a way to develop the detection tool for integrated, on‐chip devices.

Stable and Reusable Lace-like Black Silicon Nanostructures Coated with Nanometer-Thick Gold Films for SERS-Based Sensing

“…Surface-enhanced Raman spectroscopy (SERS) technique relies on the enhancement of the electric field occurring when the frequency of an excitation beam coincides with the eigenfrequency of an ensemble of conduction electrons in a metallic nanostructured substrate. , Experimentally obtained enhancement factors that vary from 10 4 to 10 11 − allow one to employ SERS to detect molecules with an extremely low Raman scattering cross-section of 10 –31 cm 2 /sr and to reduce the detectable concentration of an analyte down to 10 –11 –10 –6 M − and even to attomolar values …”

A Simple Method for the Fabrication of Silicon Inverted Pyramid Substrates for Surface-Enhanced Raman Spectroscopy

“…A large number of researchers have so far prepared SERS substrates in different 3D structures of silicon, such as nanowires [ 17 , 18 ], nanopores [ 19 ], nanocones [ 20 ], pyramids [ 21 , 22 , 23 ], and inverted pyramids [ 24 , 25 ]. Silicon inverted pyramids with anti-reflective properties favor multiple interactions of incident light compared to flat silicon and increase light absorption and the number of adsorption hot spots.…”