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 Cu 2 O nanoframes. Our strategy is a unique one-pot procedure. Simply, hollow Cu 2 O/Ag composite nanoframes (Cu 2 O/Ag CNFs) with tunable silver content have been successfully designed and constructed by reduction of Ag + with sodium citrate in a 14 day old Cu 2 O-containing mother solution, and then a second component (Ag) was directly deposited onto primary nanomaterials (Cu 2 O nanoframes).There is an optimum amount of Ag NPs. When 0.40 mM AgNO 3 is used, the prepared Cu 2 O/Ag CNFs show significantly improved SERS properties with an enhancement factor of ~10 5 . Furthermore, the enhancement mechanism, reproducibility and stability of Cu 2 O/Ag CNFs are investigated in detail. The excellent properties of the prepared Cu 2 O/Ag CNFs suggest that this substrate has a potential application in SERS detection.

Plasmonic-induced SERS enhancement of shell-dependent Ag@Cu2O core–shell nanoparticles

“…On changing the Cu 2 O thickness, a red-shi of the plasmon peaks was observed, where the plasmon wavelength of silver nanospheres was controlled by altering the coating materials and their thickness. The spectral features of the band at 600 nm shared similarities with the optical characteristics of Cu 2 O nanoshells in terms of the 37,38 The assignments of the SERS bands of the 4-MBA molecule adsorbed on Ag and Ag@Cu 2 O NPs are shown in Table 1. 43 As is shown in Fig.…”

“…The diffraction peaks located at 2q ¼ 29.4, 36.5, 42.2, 61.5, 73.7, and 77.4 can be indexed to the {110}, {111}, {200}, {220}, {311}, and {222} lattices, respectively, of the pure cubic-phase Cu 2 O nanocrystals (JCPDS: 05-0667, space group: Pn 3m, a ¼ 0.4270 nm). 37,38 The other diffraction peaks located at 2q ¼ 38.0, 44.1, 64.4, and 77.4 can be indexed to the {111}, {200}, {220}, and {311} planes, respectively, of the face-centered cubic structure of the Ag nanocrystals (JCPDS: 04-0783, space group: Fm3m, a ¼ 0.4086 nm). 39 These results indicate that the structure is composed of Cu 2 O and Ag.…”

“…4 † shows the SERS spectrum of 4-MBA (10 À3 M) adsorbed on Cu 2 O nanospheres. The spectrum shows three bands at around 401, 534, and 618 cm À1 associated with Cu 2 O,37,38 and no signicantly enhanced Raman bands for 4-MBA are observed, which indicates the absence of the SERS effect on the Cu 2 O nanospheres. Subsequently, the SERS spectra of 4-MBA (10 À3 M) adsorbed on Ag@Cu 2 O core-shell NPs samples with various Cu 2 O shell thickness and Ag NPs are compared inFig.…”

Ag–Au bimetallic nanocomposites stabilized with organic–inorganic hybrid microgels: synthesis and their regulated optical and catalytic properties

“…[19][20][21] The unique porous structure of Ag-Au bimetallic NPs is characterized by an increased number of surface active sites and a large void volume, which not only promotes electron transfer on the nanocatalyst surface, but also accelerates the reaction of the substrate in contact with the catalyst and thus improves catalytic activity. [22][23][24] The surface of bimetallic NPs is commonly coated with chemically inert protective layers (SiO 2 , dendrimers, polymers, etc.) to improve dispersity and stability.…”

Analysis on superhydrophobic silver decorated copper Oxide nanostructured thin films for SERS studies

“…Various metal oxides, namely TiO 2 , CuO and SiO 2 were modified by coating with Ag, resulting in improved SERS effect [7][8][9]. Thus there is a great opportunity in the near future for the development and engineering of metal oxide nanostructure-based SERS substrates [10,11].…”