Ascertaining genuine SERS spectra of p-aminothiophenol

By choosing the proper SERS substrate and using a low concentration of p-aminothiophenol (PATP) solution, we observed the genuine SERS spectra of PATP, in which the vibrational modes of 4,4'-dimercaptoazobenzene (DMAB) at 1140, 1390, 1432 cm(-1) are not observed, and the SERS spectra is the same as the Raman spectra of PATP powder. We compare the SERS spectra of PATP in two different SERS substrates, and find that both the plasmon enhancement and time of radiation by laser play key roles in the surface catalyzed reaction.