Formation of High-Yield Gold Nanoplates on the Surface: Effective Two-Dimensional Crystal Growth of Nanoseed in the Presence of Poly(vinylpyrrolidone) and Cetyltrimethylammonium Bromide

Abstract

This paper reports a simple technique to grow high-yield gold nanoplates directly on the surface via an effective two-dimensional growth promotion of the attached nanoseeds in the presence of a binary surfactant mixture, namely, poly(vinylpyrrolidone) (PVP) and cetyltrimethylammonium bromide (CTAB). The gold nanoplates formation strongly depended on the concentration of PVP used in the solution, while the nanoplate size depended on the CTAB concentration. In a typical process with optimum PVP and CTAB concentrations, 60% of the nanocrystal product was nanoplates. Triangular nanoplates were found to be the major shape of the nanoplates with a yield of up to ca. 50%, while hexagonal or truncated-hexagonal and rounded-nanoplates shared up to ca. 30 and 20% of the nanoplates product, respectively. The nanoplates were characterized by a very thin structure with a thickness of less than 10 nm. The edge-length size of the nanoplates was found to be up to ca. 1 µm. At optimum growth conditions, ca. 70% of the surface area was covered by nanoplates. X-ray diffraction results on the surface modified nanoplates samples indicated exceedingly high Au(111) peaks of gold nanocrystal without the presence of other peaks, such as ( 200) and ( 220), in the diffraction spectrum. The present approach may be used to produce a surface that contains unique nanostructured Au(111) crystallographic plane characteristics, which should find potential applications in catalysis, surface-enhanced Raman scattering, sensors and photonics.

Nanoscale Chemical Patterns on Gold Microplates

“…35−37 Working in concert with CTAB, iodide is believed to suppress the growth in [111], the direction normal to the top and bottom surfaces of a plate, while allowing for the incorporation of the gold atoms to the edges. 15,28 ITO substrates were directly immersed into a mixture of chloroauric acid, ascorbic acid, CTAB, and KI at an elevated temperature, 70°C. SEM images ( Figure 1A−C) showed that micrometer-sized plates were formed on ITO, and the sizes increased as the reaction time increased.…”

“…10 We note that the parallel growth of plates was also observed in other studies that synthesized nanoplates. 28,29 The attractive interaction between gold microplates and ITO reduces the surface energy of the plates. Plates parallel to the surface are stabilized by the attractive interactions.…”

(001)-Faceted hexagonal ZnO nanoplate thin film synthesis and the heterogeneous catalytic reduction of 4-nitrophenol characterization

“…1C). This phenomenon was also observed in the case of gold nanoplate growth using the HMT, where the increasing of HMT concentration produced a larger gold nanoplate size [24,25]. Effective c-axis plane passivation is considered as one of the reason in ZNPs size increment.…”

Porous (001)-faceted anatase TiO2nanorice thin film for efficient dye-sensitized solar cell

“…And in the presence of the surfactant (HMT) here via an effective adhesion of its active amine functional onto the TiO 2 nanocrystallite, presumably on (001) plane, the nanorice of anatase TiO 2 that is bounded by this plane is realized. Such feature has also been found in the one-dimensional crystal growth in the case of ZnO [26,27] and platelet [28,29], brick-shape [30], nanofibrous [31,32] and multipods [33] nanocrystal in the case of Au, Pt and Pd. Therefore, in order to obtain the extent role of HMT in the formation of (001)-faceted TiO 2 nanorice, we examined the nanocrystal growth properties under a different HMT concentration.…”