Fabrication of Cu2O/Ag composite nanoframes as surface-enhanced Raman scattering substrates in a successive one-pot procedure

Abstract

Semiconductor/metal composite nanomaterials have been used as surface-enhanced Raman scattering (SERS) active substrates and have attracted increasing attention due to their widespread applications in both optical and material fields. Here, we report a facile strategy to prepare highly sensitive SERS substrates with excellent reproducibility and stability based on uniform and well-controlled Ag nanoparticle (NP) decorated Cu₂O nanoframes. Our strategy is a unique one-pot procedure. Simply, hollow Cu₂O/Ag composite nanoframes (Cu₂O/Ag CNFs) with tunable silver content have been successfully designed and constructed by reduction of Ag⁺ with sodium citrate in a 14 day old Cu₂O-containing mother solution, and then a second component (Ag) was directly deposited onto primary nanomaterials (Cu₂O nanoframes). There is an optimum amount of Ag NPs. When 0.40 mM AgNO₃ is used, the prepared Cu₂O/Ag CNFs show significantly improved SERS properties with an enhancement factor of ~10⁵. Furthermore, the enhancement mechanism, reproducibility and stability of Cu₂O/Ag CNFs are investigated in detail. The excellent properties of the prepared Cu₂O/Ag CNFs suggest that this substrate has a potential application in SERS detection.