Recyclable and ultrasensitive SERS sensing platform: Deposition of atomically precise Ag152 nanoclusters on surface of plasmonic 3D ZnO-NC/AuNP arrays

Abstract

It is well known that the intensity and density of hot spots directly determine the surface-enhanced Raman scattering (SERS) performance of a substrate. In this work, we proposed a new strategy to improve the density of hot spots of a SERS substrate by innovatively introducing atomically precise Ag nanoclusters (Ag152(SCH2CH2Ph)60, ~2 nm). First, a 30 nm gold nanoparticle (AuNP) film in conjunction with hexagonal zinc oxide nanocone (ZnO-NC) arrays is prepared as a three-dimensional (3D) backbone; these ZnO-NC/AuNP arrays provide numerous anchors to facilitate the loading of Ag152 nanoclusters, thereby further enhancing the intensity and density of hot spots on the entire substrate. In addition, the ultra-small particle size of the Ag152 nanoclusters will not cover the original hot spots on the surface of AuNP film during deposition. Thus, the ZnO-NC/Au/Ag152 3D SERS sensing platform shows the capability of ultra-sensitive detection, and the substrate results in an enhancement factor (EF) of up to 6.48 × 109. More importantly, the prepared substrate can act as an environmentally friendly sensing platform to achieve rapid self-cleaning and recycling through photocatalysis. The present work confirms the application prospects of novel metal nanoclusters in the field of SERS and photocatalysis.