Laser-Driven Plasmonic Bubble Gold Nanorod Clusters with ∼1 nm Gaps for Highly Sensitive SERS Detection

Surface-enhanced Raman spectroscopy (SERS) is closely related to the SERS substrate. SERS substrate should not only possess small gaps to generate strongly enhanced hot spots but also facilitate the entry of target molecules into these hot spots. However, the presence of ligands on the substrate can create steric hindrance, potentially impeding the access of target molecules to hot spots. In this study, we assembled a dense gold nanorod (AuNR) cluster with gaps of similar to 1 nm, utilizing laser-driven plasmonic bubbles. The AuNR cluster through laser-driven plasmonic bubbles was accompanied by the reduction of the ligands. The AuNR cluster can detect crystal violet solutions at concentrations as low as 10(-12) M and allows for the SERS identification of various molecules. Furthermore, the practical potential of this AuNR cluster was demonstrated by the detection of 10 ppb of paraquat on the tomatoes in situ. This work provides new insights into the assembly of laser-driven plasmonic bubbles with noble metal nanoparticles and their application in the field of SERS.