摘要
The electromagnetic field coupling between two kinds of noble metal nanoparticles endows high surfaceenhanced Raman scattering(SERS) activity but is accompanied by uneven hot spots.Using two-dimensional semiconductors with localized surface plasmon resonance(LSPR) effects instead of one of the noble metal components can effectively improve uniformity.Hence,the Ag nanoparticles(Ag NPs) loaded MoO_(3-x) nanoflowers(Ag/MoO_(3-x)) were engineered to exploit dual-plasmonic coupling and realize the trace detection of aldehyde volatile organic compounds(VOCs) gas.The finite-difference time-domain(FDTD) simulation results proved that there is an obvious electromagnetic field coupling effect between Ag NPs and MoO_(3-x) semiconductors,which can amplify the molecular dipole moment significantly.The chemical enhancement mechanism in the Ag/MoO_(3-x) substrate was clarified by band structure analysis,in which the free electrons accumulated at the bottom of the conduction band of the MoO_(3-x) semiconductor can promote the charge transfer process between Ag/MoO_(3-x) and the 4-aminothiophenol(4-ATP) molecule.Moreover,the electron delocalization of 4-ATP molecule was enhanced after being absorbed on Ag/MoO_(3-x) nanoflowers,facilitating the charge transfer between 4-ATP and Ag/MoO_(3-x) substrate effectively.Importantly,using the 4-ATP molecule as a probe,the trace detection of a variety of aldehyde VOCs gas was realized by Ag/MoO_(3-x).substrate with a low limit of detection(LOD) of 10 ppb.This work provided a new idea for the design of noble metal-plasmonic semiconductor heterostructure substrates.
基金
financially supported by the National Natural Science Foundation of China(Nos.52473250,12274018,32311530040,5222602,and 12374390)
the National Science and Technology Major Project(No.2023ZD0500902)
the Key Scientific and Technological Special Project of Ningbo City(No.2023Z209)
the Member of Youth Innovation Promotion Association Foundation of CAS(No.2023310)
Ningbo Youth Science and Technology Innovation Leading Talents Project(No.2024QL029)
