Electric Field-Induced Enhanced Raman Spectroscopy Sensor and Photocatalysis with Thermoelectric–Plasmonic Metal Nanocomposites

Electric field-induced surface-enhanced Raman scattering (E-SERS) substrates have been proven to further enhance the attained Raman intensity. Herein, integrated with plasmonic Ag nanoparticles (Ag NPs), the thermoelectric Bi₂Te₃ plate as an E-SERS substrate decreased the limit of detection by 2 orders of magnitude and increased the SERS signal by >20 times compared to those without electrical field induction. The thermoelectric potential produced by the Bi₂Te₃ plate could modulate the electron density and subsequently change the Fermi level of Ag. This increases the resonant electron transition probability using a broad range of molecules. The plasmon-activated catalytic reactions of the interconversion between <i>p</i>-nitrothiophenol and <i>p</i>,<i>p</i>'-dimercaptoazobenzene could be controlled through the E-SERS template. On the basis of the finite element method, explicit theoretical analysis indicated that the Ag NP-Bi₂Te₃-molecule charge transfer could improve our understanding of the SERS and photocatalytic mechanism.