The surface-enhanced Raman scattering from ZnO nanorod arrays and its application for chemosensors

Based on the surface-enhanced Raman scattering (SERS) of two similar probe molecules, 4-mercaptopyridine (4-MPY) and 4-aminothiophenol (PATP) from the ZnO nanorod arrays (ZnONRs) substrates, the prerequisite of SERS for ZnONRs-molecules system was investigated. The results indicated that the realization of efficient photo-induced charge transfer between ZnONRs and the probed molecules is a critical prerequisite to magnify polarizability tensor of the probed molecular and realize SERS. Such results were also verified by the SERS performance of the dye (Bu₄N)₂[Ru(dcbpyH) ₂-(NCS)₂] (N719) and acetaminophen as the probe molecules on the ZnONRs substrates. The linear relation between the logarithmic concentrations and Raman peak intensities afforded quantitative detection of N719 and acetaminophen. Significantly, the evident SERS response of N719 and acetaminophen from the ZnONRs substrates not only provided a significant insight into the behaviors of the photo-induced charges for dye-sensitized solar cells (DSSCs), but also demonstrated that the present SERS-active substrate could be utilized as a chemosensor for pharmaceutical analysis.