Convective combined interfacial assembly of surfactantless ordered Au nanoparticles and SERS performance

Abstract

Preparing ordered array of nanoparticles through interface assembly has been an effective way in synthesis of SERS substrates. However, transferring the interfacial film to solid substrates without disturbance has been difficult for a long time. Herein, we developed a novel strategy for transferring the interfacial film comprising Au nanoparticles (NPs) to arbitrary solid substrates without disturbance. After a continuous sheeny Au NP film was formed at the hexane/water interface, an in situ quadratic convective arrangement was performed with the drawdown of interface film by controlling the dropping speed of a Teflon funnel, depositing ordered Au NP films onto solid substrates. Both the SERS mapping results and low values of relative standard deviations (RSD) of Raman intensity obtained from crystal violet (CV) molecules show that the as-prepared Au NPs arrays are of sensitive and uniform SERS properties. This improved technique is superior to existing methods in self-assembly since there is no disturbance during the transferring, which can be applied to general colloidal crystals to fabricate large-scale monolayer films.