In situ synthesis of hybrid zinc oxide-silver nanoparticle arrays as a powerful active platform for surface-enhanced Raman scattering detection

Abstract

Micro-structured molecular semiconductor film-based surface-enhanced Raman scattering (SERS) probes are an important analytical tool for both fundamental and technological research. This study proposed a novel zinc oxide (ZnO)-based, three-dimensional (3D) semiconductor nanoflower (NF) superstructure probe with unique physicochemical properties, including engineered hotspots allowing an arrangement of metallic nanoparticles (NPs), as a means to analyse target molecules. By changing the size, high-density hotspots distributed throughout the nanopetal-like ‘nanorods’ of ZnO supports. When used to analyse crystal violet (CV), there were synergistic effects of silver (Ag), ZnO, and CV molecules in the synthesised ZnONFs@Ag-CV SERS system. The SERS results revealed that the plasmonic surfaces of the self-assembled hotspots on the 3D ZnO superstructures provided effective molecular interactions between the ZnONFs@Ag platform and the Raman probe molecule. These interactions influenced the configuration and detection performance of SERS. Moreover, the performance was closely associated with enhancement of the electromagnetic mechanism and the charge transfer contribution in the platform between the semiconductor, metallic NPs, and the analyte molecules. As a result, the characteristic CV peaks were obvious even at a low concentration of 10−10 M. In a mixture of two probes, the ZnONFs@Ag chip provided an outstanding selectivity in the quantitative and qualitative evaluation of each target molecule at low concentrations. The synthesised 3D ZnONFs@Ag heterostructure chip possesses excellent practical reproducibility and represents a promising candidate for chemical and biomedical inspection.