Surfactant-free electrochemical synthesis of layered Ag/Au bimetallic nanostructures as SERS platforms with DFT insights into their interfacial charge transfer mechanism.
- 1School of Chemistry and Life Sciences, Hanoi University of Science and Technology 1 Dai Co Viet Hanoi Vietnam.
- 2Institute of Research and Development, Duy Tan University Da Nang 550000 Vietnam.
- 3School of Engineering and Technology, Duy Tan University Da Nang 550000 Vietnam [email protected] [email protected].
Abstract
Bimetallic nanoparticles have attracted significant interest in Surface-Enhanced Raman Scattering (SERS) due to their superior optical and synergistic properties. In this study, layered Ag@Au bimetallic nanostructures were fabricated on Indium Tin Oxide (ITO) glass via a surfactant-free electrochemical approach combining linear sweep voltammetry (LSV) and chronoamperometry (CA). This method rapidly yields clean, highly active plasmonic interfaces, effectively eliminating the competitive adsorption typically caused by chemical stabilisers. By featuring a rugged morphology and an exposed bimetallic interface, the optimal substrate generates abundant electromagnetic hot spots to deliver superior SERS sensitivity for Nile Blue A (NBA). Interestingly, the empirical spectra exhibited a highly selective, vibrational-mode-dependent signal amplification, indicating a restricted, perpendicular adsorption orientation of the NBA molecules within the bimetallic nanogaps. To fundamentally elucidate the localised Chemical Enhancement (CE) mechanism driving this selective behaviour, Density Functional Theory (DFT) calculations were performed on representative pyramidal clusters. Consistent with the stoichiometry of the superior experimental substrate, the computational models demonstrated that the bimetallic Ag₁₆Au₄ cluster yields the strongest SERS enhancement. Charge density difference (CDD) maps and natural population analysis (NPA) showed that the largest electron transfer from the NBA ligand to the Ag₁₆Au₄ cluster occurred through the interaction between the N atom of the oxazine ring and the Au atom at the top of the cluster, resulting in the greatest enhancement. Hence, this synergistic experimental-theoretical approach paves the way for the design of bimetallic sensors for advanced environmental analysis.
Related
- Engineering Cu/Ni-O Nanostructures via Bimetallic MOF Conversion for High-Performance Asymmetric Supercapacitors
- Interfacial engineering of an amino-functionalized bimetallic NiNd-MOF decorated MoS2 heterostructure for enhanced symmetric supercapacitor performance
- Innovative AuAg bimetallic nanoparticle synthesis using food waste materials: its biological applications and photocatalytic degradation potentials
- Janus Nanostructures Enabled by Confined Interfacial Engineering for Enhanced Electromagnetic Response
- Gold–graphene quantum dot hybrid nanostructures for solar-to-chemical energy conversion: interfacial charge dynamics, hydrogen evolution, and water splitting
BibTeX
@article{ngo2026surfactantfree,
title = {{Surfactant-free electrochemical synthesis of layered Ag/Au bimetallic nanostructures as SERS platforms with DFT insights into their interfacial charge transfer mechanism.}},
author = {Minh Nhat Ngo and Hang Thi-Thu Le and Thi Chinh Ngo and Mai Thi-Tuyet Nguyen},
journal = {RSC advances},
year = {2026},
month = oct,
doi = {10.1039/d6ra08211d},
url = {https://europepmc.org/article/MED/42948393},
note = {CC BY},
}
RIS
TY - JOUR
TI - Surfactant-free electrochemical synthesis of layered Ag/Au bimetallic nanostructures as SERS platforms with DFT insights into their interfacial charge transfer mechanism.
AU - Minh Nhat Ngo
AU - Hang Thi-Thu Le
AU - Thi Chinh Ngo
AU - Mai Thi-Tuyet Nguyen
PY - 2026
DA - 2026/10/27
JO - RSC advances
DO - 10.1039/d6ra08211d
UR - https://europepmc.org/article/MED/42948393
AB - Bimetallic nanoparticles have attracted significant interest in Surface-Enhanced Raman Scattering (SERS) due to their superior optical and synergistic properties. In this study, layered Ag@Au bimetallic nanostructures were fabricated on Indium Tin Oxide (ITO) glass via a surfactant-free electrochemical approach combining linear sweep voltammetry (LSV) and chronoamperometry (CA). This method rapidly yields clean, highly active plasmonic interfaces, effectively eliminating the competitive adsorption typically caused by chemical stabilisers. By featuring a rugged morphology and an exposed bimetallic interface, the optimal substrate generates abundant electromagnetic hot spots to deliver superior SERS sensitivity for Nile Blue A (NBA). Interestingly, the empirical spectra exhibited a highly selective, vibrational-mode-dependent signal amplification, indicating a restricted, perpendicular adsorption orientation of the NBA molecules within the bimetallic nanogaps. To fundamentally elucidate the localised Chemical Enhancement (CE) mechanism driving this selective behaviour, Density Functional Theory (DFT) calculations were performed on representative pyramidal clusters. Consistent with the stoichiometry of the superior experimental substrate, the computational models demonstrated that the bimetallic Ag₁₆Au₄ cluster yields the strongest SERS enhancement. Charge density difference (CDD) maps and natural population analysis (NPA) showed that the largest electron transfer from the NBA ligand to the Ag₁₆Au₄ cluster occurred through the interaction between the N atom of the oxazine ring and the Au atom at the top of the cluster, resulting in the greatest enhancement. Hence, this synergistic experimental-theoretical approach paves the way for the design of bimetallic sensors for advanced environmental analysis.
SN - 2046-2069
ER -