Ligand Controlled Morphology Evolution of Active Intermediates for the Syntheses of Gold Nanostars

Abstract

Gold nanostars have unique plasmonic properties that are related to the highly branched nanostructures. However, it is challenging to precisely control these branches. Here we studied the reaction kinetics on the seed-mediated growth process of gold nanostars using in situ UV-vis spectroscopy. The impact of hydroquinone ligands on the formation and evolution of active intermediates was systematically explored. In addition, we improved the classical seed-mediated method to achieve a much better control on the final morphology of gold nanostars by a sudden addition of a high concentration ligand solution. Our method can significantly advance the syntheses of gold nanostars and provide numerous opportunities to prepare nanomaterials with unique morphology and plasmonic properties.

Insight into growth of Au–Pt bimetallic nanoparticles: an in situ XAS study

“…However, as the reaction proceeds, the SPR peak shows a blue shift and at 50 s it appears at 520 nm corresponding to < 10 nm particle size. A similar phenomenon of the appearance of the SPR peak at higher wavelength and its blue shift during the reaction has been found by other workers also (Meng et al, 2016). This can be attributed to the effect of the block copolymers engulfing the gold particles resulting in formation of branched intermediates during the reaction.…”

One-step preparation of multifunctional alginate microspheres loaded with in situ-formed gold nanostars as a photothermal agent

“…In this process, alginate chains act as a soft template to prevent the aggregation and precipitation of Au NPs. Unlike the reported two-step preparation of Au NSs, [29][30][31] extra surfactant and careful control of reaction conditions were not required. Au content in Au@CA microspheres was also evaluated by using the AAS method (Table S1, ESI †).…”

“…Therein, the use of a reducing agent and cationic surfactant may cause potential toxicity. [29][30][31] Therefore, the development of a simple and green method for multifunctional embolic materials based on Au NSs still remains a challenge.…”

Bespoke nanostars: synthetic strategies, tactics, and uses of tailored branched gold nanoparticles

“…42 In the synthesis of seedmediated gold nanostars utilizing hydroquinone as both a capping and reducing agent it was discovered that such a blueshift during particle evolution could be minimized relatively by lowering the relative seed concentration. 43 The lower seed population may allow for more complete surface adsorption by the hydroquinone, arresting further possible evolution. 44 This facile method for morphological and size control of branched nanoparticles was demonstrated by the Vo-Dinh group in their seed-based, silver-mediated synthesis of gold nanostars for in vivo tumor imaging.…”