Gold nanorings synthesized via a stress-driven collapse and etching mechanism

Abstract

Toroidal Au or Ag nanostructures are of particular interest due to their unique optical responses and superior catalytic applications. However, the fabrication of ring-like Au or Ag nanostructures is limited to either electron beam lithography or template techniques, thus hampering their applications. Here, we present a new stress-driven structure collapse and etching mechanism to synthesize Au nanorings via a direct one-pot solution-based chemical reaction. The nanoparticle-mediated recrystallization process contributes to the formation of Au nanoframes, which contain unusual stress, thus promoting the breakup of the nanoframes and finally converting them into Au nanorings. The Au nanorings with tunable hole sizes exhibit interesting localized surface plasmon features owing to the coupling of bonding and antibonding modes on the inner and outer surfaces of the nanorings. This facile approach may open the door for the preparation of toroidal nanostructures in other compositions for numerous applications.

Designing Novel Nonsymmetric Ag/AgI Nanoplates for Superior Photocatalytic Activity

“…For example, a similar growth mode has been observed in the growth of nonsymmetric ZnO nanodisks and nanorings, in which bis(2‐ethylhexyl) sulfosuccinate (NaAOT) serves as soft template for the limited growth of 2D nanostrcures . Similarly, in our recent study, in the case of Au nanoplate, hexagonal Au disks with one side smooth and the other concave was formed using PEG‐water soft template …”

“…When enough of KI and EG molecules connect together, 2D EG–KI soft templates will be formed in the synthesis solution, as shown in Figure C. This situation is similar to the 2D water‐PEG soft template in our recent work in which Au nanoplates have been synthesized …”

“…In order to realize the control for the metal NPs on the partial selected surface of semiconductor, in this work, a soft‐template strategy is developed to obtain a nonsymmetric heterostructure on 2D Ag/AgI nanoplate. The concept of soft template to synthesize such asymmetric heterostructures is provoked from our previous work that using PEG (polyethylene glycol)‐water as soft template, asymmetric Au nanoplate with one side surface smooth and the other side sunken was achieved . Here, a soft template formed by ethylene glycol (EG) and potassium iodide (KI) is exploited to synthesize the nonsymmetric Ag/AgI nanoplate.…”

Engineering Single Nanopores on Gold Nanoplates by Tuning Crystal Screw Dislocation

“…It has been previously reported that high-density crystallographic defects in the center of large semiconductor and metal nanoplates can lead to structural collapse and etching, forming ring- or frame-like structures. [38–40] In contrast, the nanoplates (with a central pore) obtained here exhibit nearly perfect crystal lattices (Figure 1c). This is further demonstrated by the selected area electron diffraction (SAED) measurement taken from single Au nanoplate (Figure 1d) where the diffraction pattern can be attributed to single crystalline Au with parallel stacking faults.…”

“…This line structure is different from other continuous and randomly oriented darker lines (pointed by the red arrows), which are commonly observed in thin Au nanoplates and have been attributed to bending. [37, 38] By analyzing the central region via HRTEM (Figure 1c and Figure S2), the average diameter of the pores is only 0.85 ± 0.08 nm. The yield of the Au nanoplates with nanopores are generally greater than 90%, in which ~ 60% of the nanoplates contain a single pore, whereas the others have two or three pores.…”