Electrochemical Surface-enhanced Raman Spectroscopy for Structure Analysis of 1, 4-benzenedithiol Assembled on Gold Nanoparticles

1, 4-benzenedithiol (BDT), is a very important Raman probe molecule in the study of surface-enhanced Raman spectroscopy (SERS) because of containing benzene ring structure with large Raman differential scattering cross section and sulfhydryl group to adsorb on gold or silver nanostructures. However, there were significant differences in SERS spectra reported in different literatures, which caused interference for precise chemical measurement by using SERS spectra of BDT molecules. Here, electrochemical SERS (EC-SERS) was used to successfully analyze the spectral characteristics of BDT spontaneously forming dimers with disulfide bonds. The results showed that when the reductant NaBH4 was used to pretreat BDT solution, the SERS spectra of BDT showed the characteristics of BDT monomer, similar to the spectrum of BDT assembled on gold nanoparticles (Au NPs) at negative potential. When the oxidizer H2O2 was used to pretreat BDT solution, the SERS spectrum of BDT showed the characteristics of BDT dimer, similar to the spectrum of BDT assembled on Au NPs at open circuit potential. This study revealed the intrinsic SERS spectrum of BDT, which is of great significance for quantitative analysis of BDT as Raman probe molecule.