Formation and Stability of Gold Nanoflowers by the Seeding Approach: The Effect of Intraparticle Ripening

Abstract

The seeding approach for preparation of gold nanoflowers in which 25 nm gold nanoparticles were used as the seeds and a mixture of HAuCl4 and hydroxylamine as growth solution was investigated systematically. It is revealed that the formation and stability of the nanoflowers were affected greatly by the intraparticle ripening induced by the chlorine ions that existed in the reaction system. In this seeding approach, hydroxylamine promoted the rapid reduction of HAuCl4 and thus rapid formation of small Au particles with a diameter around 3 nm in the growth solution. The attachment of the small particles on the seed surface contributed to the growth of the nanoflowers. The branch length of the nanoflowers increased with the increased pH of the growth solution due to the suppressed ripening at higher pH. The stability of the nanoflowers can be improved by increasing the pH of the storing solution and/or removal of the chlorine ions.

Multicolor immunochromatographic strip test based on gold nanoparticles for the determination of aflatoxin B1 and fumonisins

“…Small s-GNPs (SPR band at 518 nm corresponding to a mean diameter of approximately 11 nm) were used as the seeds and a mixture of HAuCl4, sodium citrate and hydroquinone as the growth solution. It is somewhat unclear if the growth of the branch is dominated by the epitaxial mechanism or by the random attachment of the small GNPs on the seeds surface [22], however, the hypothesis is the occurring stepwise reduction of Au III to Au I by citrate and Au I to Au 0 by hydroquinone [21].…”

“…Although QDs are particularly suited for multiplexing because of the tunable color of the emitted fluorescence, still they require a light source for excitation, thus limiting the portability and cost-effectiveness of QD-based ICSTs. Metal nanoparticles also offer the opportunity of tailoring the SPR band (and thus the color) by varying NP dimension and shape [21][22]. In fact, the advantage of using differently shaped and therefore differently colored silver nanoparticles as labels for multiplex ICST has been demonstrated by Yen et al [23].…”

Facile Synthesis of Multi‐Branched Gold Nanostructures through a TBAB‐Assisted Route in Aqueous Solution and Their SERS Property

“…For instance, using a seed-mediated growth process, Yuan and his coworkers 8 synthesized multi-branched urchin-like gold nanoparticles in the AgNO 3 -ammoniacal solution. Yang 17 and his coworkers prepared gold nanoflowers by using 25 nm gold nanoparticles as the seeds and a mixture of HAuCl 4 and hydroxylamine as growth solution. But their application is restricted because of tedious work involved in the preparation.…”

Assembling ZnO Nanorods into Microflowers through a Facile Solution Strategy: Morphology Control and Cathodoluminescence Properties

“…Ni et al reported flowerlike ZnOZnS heterogeneous microstructures built up by ZnSparticle-strewn on ZnO microrods by a hydrothermal route [8]. Some other flowerlike and hierarchical micro/ nanostructures (including metal or ternary compounds) were also reported, such as Au [9] [27][28][29], electrochemical deposition [30][31]. Among them, the solution approach has been proved to be an efficient way with outstanding advantages, such as simplicity, commercial feasibility and potential for scaling up.…”

“…Ni et al reported flowerlike ZnOZnS heterogeneous microstructures built up by ZnSparticle-strewn on ZnO microrods by a hydrothermal route [8]. Some other flowerlike and hierarchical micro/ nanostructures (including metal or ternary compounds) were also reported, such as Au [9], Bi 2 SiO 5 [10], Bi 2 S 3 [11], ZnS [12], InP [13], SnO 2 [14] and ZnS-ZnO heterostructures [15].…”