Scheme 1. Schematic representation of the synthesis procedure, the SERS sensing and the self-reviving ability for the SERS substrate based on the Ag/Au/AgCl heterostructure.

Technology Overview
The Ag/Au/AgCl heterostructure is prepared by the photoreduction from Ag nanowires. Efficient SERS enhancement is achieved by electromagnetic and chemical mechanisms. High enhancement factors about 10⁷ ~ 10⁸ are achieved for analgesics and antibiotics. Effective separate and multiplex SERS detection towards PCT and FZD is presented. Reusability of SERS substrates is realized by photo-cleaning ability of Ag/Au/AgCl.

Applications & Benefits
We demonstrated the greatly improved cell stability under water, showing that the PSCs could potentially be used in water and other aqueous media to facilitate the solar driven electrical chemical reactions. These demonstrations also showed that the perovskite photovoltaic technologies have the potential to be commercialized and used in a broad range of green energy and storage applications.

Abstract：
The composite nanostructure composed of semiconductors and noble-metals have received widespread attention in the field of surface-enhanced Raman scattering (SERS). Herein, one-dimensional (1D) silver/gold/silver-chloride nanowires (Ag/Au/AgCl NWs) are prepared using the facile hydrothermal and photoreduction processes for the SERS detection of antibiotics and analgesics. The nanometer-scale interparticle gaps in the Ag/Au/AgCl heterostructure have been produced and the hotspots are provoked to enhance the SERS signal of target molecules by boosting the synergistic action of the heterostructure. The Ag/Au/AgCl heterostructure offers high sensitivity, good uniformity and high reproducibility. Meanwhile, the SERS substrate based on the Ag/Au/AgCl heterostructure is studied for the determination of paracetamol (PCT) and furazolidone (FZD) with the wide linear ranges of 10^-1 M ~ 10^-10 M and 10^-1 M ~ 10^-9 M. Their corresponding limits of detection (LOD) are as low as 2.8 × 10^-12 M and 1.9 × 10^-11 M, respectively. The separate and multiplex detection of PCT and FZD by the Ag/Au/AgCl heterostructure have been performed. Furthermore, the Ag/Au/AgCl heterostructure is successfully applied to determine the PCT and the FZD in the human urine samples with satisfactory results. To ensure the self-reviving ability of Ag/Au/AgCl heterostructure, the photodegradation of PCT and FZD molecules has been conducted and analyzed. The SERS substrate based on the semiconductor/noble-metal heterostructure with the self-reviving capability paves the way for the accurate detection of biologically important molecules like antibiotics and analgesics at the ultralow-level concentrations.

Photochemical synthesis of Ag/Au/AgCl heterostructure from Ag nanowires as a reusable SERS substrate for ultrasensitive detection of analgesics and antibiotics
Author：Riswana Barveen N., Wang T.-J., Chang Y.-H.
Year：2021
Source publication：Chemical Engineering Journal
Volume 423  130191
Subfield Highest percentage：99%    Industrial and Manufacturing Engineering    #3/336

https://www.sciencedirect.com/science/article/pii/S1385894721017794