Laser-induced chemical transformation of PATP adsorbed on Ag nanoparticles by surface-enhanced Raman spectroscopy—A study of the effects from surface morphology of substrate and surface coverage of PATP

Abstract

The laser induced transformation of p-aminothiophenol (PATP) to p,p′-dimercaptoazobenzene (DMAB) has attracted intensive interest recently, in which localized surface plasmon resonance (LSPR) assisted photocatalysis has been demonstrated to play an important role. In this paper, we systematically investigate the factors that influence the reaction for further understanding the mechanism using surface-enhanced Raman spectroscopy. The laser-induced formation of DMAB was found to depend on the surface coverage of PATP, the aggregation state of NPs, and the laser power. The disappearance of DMAB Raman signal at very low concentration of Ag NPs reveals that DMAB may only be formed between the neighboring NPs that can provide a suitable distance for the interaction between adsorbed PATP molecules.