High‐Yield Synthesis of Hollow Octahedral Silver Nanocages with Controllable Pack Density and Their High‐Performance Sers Application

Abstract

Nanoparticle-assembled octahedral Ag nanocages with sharp edges have been successfully synthesized through a Cu O-based template-assisted strategy. In the reaction system, Ag nanoparticles can be self-assembled on the surface of Cu O octahedrons, which is accomplished by the reduction of Ag by NaBH in the presence of sodium citrate as a capping agent. The hollow octahedral Ag nanocages are obtained after removing the inner Cu O cores with acetic acid. According to the scanning electron microscopy (SEM) and transmission electron microscopy characterization, the Ag nanocages are weaved by small nanoparticles, the rough surfaces are bestrewed with pores and sharp edges. It is found that the pack density of Ag nanoparticles strongly affects the surface enhanced Raman scattering (SERS) activities. The as-prepared 1.05-Ag cages with optimal pack density have suitable interparticle distance and suitable size of pores, which significantly enhance SERS signals. The SERS signals of rhodamine 6G (R6G) molecules can be detected at an ultralow concentration of 10 m when 1.05-Ag cages are used as substrates. In addition to sensitivity, 1.05-Ag cages also exhibit good reproducibility. It is expected that the ultrahigh sensitivity will endow the Ag nanocages to become a promising candidate as high-performance SERS-based chemical sensor.

Composition-adjustable Ag–Au substitutional alloy microcages enabling tunable plasmon resonance for ultrasensitive SERS

“…Secondly, after etching the Cu 2 O core with acetic acid, octahedral hollow porous Ag microcages (MCs) were obtained (Process ). 38 Finally, through a novel NaBH 4 -cooperative GRR, octahedral hollow porous Ag–Au SAMCs were successfully synthesized (Process ). Different to conventional GRR, the synergistic co-reduction of Au 3+ and Ag + to obtain Ag–Au SAMCs should be ascribed to the cooperation with NaBH 4 in the system.…”

Polarized and non‐polarized Raman spectroscopy of ZnO crystals: Method for determination of crystal growth and crystal plane orientation for nanomaterials

“…[25] Therefore, simpler methods, requiring little, or no, sample preparation are desirable to assess crystal orientation of crystals in the 100-to 1000-nm-size range. Crystal growth of metal oxides [26][27][28] and inorganic-organic materials [29,30] can conveniently be studied with Raman spectroscopy. Detailed interpretations of the local orientation of crystal planes, however, require that full assignments of vibrations and their orientation dependence have been obtained previously, as imperfect crystals and surface states in growing particles can complicate the situation.…”

Low temperature-boosted high efficiency photo-induced charge transfer for remarkable SERS activity of ZnO nanosheets

“…S11. † The C-H out-of-plane bending vibration peak intensity (613 cm À1 ; b 2 mode) 45 of the R6G molecule adsorbed on d-ZnO NSs at different temperatures is shown in Fig. 3b.…”