The Role of Bromide Ions in Seeding Growth of Au Nanorods

Garg, Niti; Scholl, Clark; Mohanty, Ashok; Jin, Rongchao

doi:10.1021/la100446q

Cited by 136 publications

(180 citation statements)

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“…[29] Recent work by Jin et al demonstrated that Br À indeed acts as a crucial shape-directing agent for gold nanorod formation in the seed-mediated process. [30] It has also been found that addition of electrolytes has a great impact in controlling the nanocrystal shapes. [13,31] Indeed, halide ions interact with gold surfaces and the interaction strength follows the increasing order of F À < Cl À < Br À < I À .…”

Section: Introductionmentioning

confidence: 99%

Short Gold Nanorod Growth Revisited: The Critical Role of the Bromide Counterion

Leduc

Delville

et al. 2011

ChemPhysChem

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A one-step, surfactant-assisted, seed-mediated method has been utilized for the growth of short gold nanorods with reasonable yield by modifying an established synthesis protocol. Among the various parameters that influence nanorod growth, the impact of the bromide counterion has been closely scrutinized. During this study it has been shown that, irrespective of its origin, the bromide counterion [cetyltrimethylammonium bromide (CTAB) or NaBr] plays a crucial role in the formation of nanorods in the sense that there is a critical [Br(-)]/[Au(3+)] ratio (around 200) to achieve nanorods with a maximum aspect ratio. Beyond this value, bromide can be considered as a poisoning agent unless shorter nanorods are required. The use of AgNO(3) helps in symmetry breaking for gold nanorod growth, whereas the bromide counterion controls the growth kinetics by selective adsorption on the facets of the growth direction. Thus, a proper balance between bromide ions and gold cations is also one of the necessary parameters for controlling the size of the gold nanorods; this has been discussed thoroughly. The results have been discussed based on their absorption spectra and finally shape evolution has been confirmed by TEM. Due to their efficient absorption in the near-IR region, these short nanorods were used in photothermal imaging of living COS-7 cells with improved signal-to-background ratios.

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Section: Introductionmentioning

confidence: 99%

Short Gold Nanorod Growth Revisited: The Critical Role of the Bromide Counterion

Leduc

Delville

et al. 2011

ChemPhysChem

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“…During the last decades gold nanorods have attracted considerable attention (Busbee et al 2003;Chang et al 1999;Gao et al 2003;Garg et al 2010;Jana et al 2001a, b;Jiang et al 2006;Jiang and Pileni 2007;Kang et al 2003;Keul et al 2008;Kim et al 2002;Liu et al 2004;Liu and Guyot-Sionnest 2005;Martin 1996;Nikoobakht and El-Sayed 2003;Park et al 2006;Pérez-Juste et al 2004;Murphy 2004, 2007;Smith and Korgel 2008;Smith et al 2009;Wirtz et al 2002;Wu et al 2007;Yacamán et al 2001;Yu et al 1997) due to their unique size-and shape-dependent properties (Pérez-Juste et al 2005;El-Sayed 2001). Various approaches to synthesize this kind of particle morphology have been developed, such as electrochemical (Chang et al 1999;Yu et al 1997), photochemical (Kim et al 2002;Esumi et al 1995) or template-based methods (Martin 1996;Wirtz et al 2002), microwave rapid heating (Liu et al 2004) and the seed-mediated growth method (Busbee et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Various approaches to synthesize this kind of particle morphology have been developed, such as electrochemical (Chang et al 1999;Yu et al 1997), photochemical (Kim et al 2002;Esumi et al 1995) or template-based methods (Martin 1996;Wirtz et al 2002), microwave rapid heating (Liu et al 2004) and the seed-mediated growth method (Busbee et al 2003). In particular, the latter-which was first introduced by Murphy and co-workers in 2001 (Jana et al 2001a)-was in the focus of various studies (Busbee et al 2003;Gao et al 2003;García et al 2011;Garg et al 2010;Grzelczak et al 2008;Jiang et al 2006;Jiang and Pileni 2007;Kang et al 2003;Keul et al 2008;Liu and GuyotSionnest 2005;Nikoobakht and El-Sayed 2001;Park et al 2006;Pérez-Juste et al 2004;Sau and Murphy 2004;Smith and Korgel 2008;Wu et al 2007). The basis of all modified seed-mediated growth procedures is the addition of a certain amount of small gold colloids (a socalled seed solution) to a so-called growth solution containing a surfactant (typically cetyltrimethylammonium bromide (CTAB)), a gold salt (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Hereby, two different approaches of the seed-mediated growth method have to be considered: with and without the addition of silver nitrate. The addition of a small amount of silver nitrate to the growth solution commonly leads to a high yield of short aspect ratio nanorods (aspect ratio between 2 and 3) (Garg et al 2010;Jiang et al 2006;Jiang and Pileni 2007;Keul et al 2008;Liu and GuyotSionnest 2005;Nikoobakht and El-Sayed 2001;Sau and Murphy 2004;Smith and Korgel 2008;Grzelczak et al 2008;García et al 2011), while the synthesis of gold nanorods without silver nitrate commonly yields higher aspect ratios (5-23), however, in a relatively low yield (Jana et al 2001a;Kang et al 2003). That means, besides rods also other shapes such as spherical particles and triangular prisms emerge in the latter situation and thus, a particle separation process has to be applied after the synthesis (Koeppl et al 2012).…”

Section: Introductionmentioning

confidence: 99%

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Seed-mediated synthesis of gold nanorods: control of the aspect ratio by variation of the reducing agent

et al. 2013

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Seed-mediated growth methods involving reduction of tetrachloroaurate(III) with ascorbic acid are common for the synthesis of gold nanorods. This study shows, however, that simply by appropriate choice of the reducing agent a drastic influence on the aspect ratio can be attained. Weaker reducing agents, such as dihydroxybenzene isomers (hydroquinone, catechol or resorcinol) or glucose can increase the aspect ratio of the nanorods by an order of magnitude, up to values as high as 100 (nanowires). The increase in aspect ratio is mainly a consequence of an increase in length of the particles (up to 1-3 lm). This effect is probably associated with a decrease in the reduction rate of gold(III) species by dihydroxybenzenes or glucose compared to ascorbic acid. The reduction potential of the reducing agents strongly depends on the pH value, and related effects on the dimensions of the nanoparticles are also reflected in this study. The nanorods exhibited penta-twinned nature without noteworthy defects (e.g. stacking faults and dislocations).

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“…19 Considerable effort has been directed toward preparing triangular gold nanoprisms and nanoplates. 2026 Moreover, halide ions, 23,27,28 Ag + ions, 29,30 and other chemicals promote the anisotropic growths of gold nanoparticles.…”

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confidence: 99%

Effects of Ag+ and Cu2+ Ions on the Shape of Triangular Gold Nanoparticles

2012

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Triangular gold nanoplates were prepared by the tartaric acid reduction of HAuCl 4 in cationic surfactant solutions, in the absence and the presence of small amounts of AgNO 3 and CuSO 4 . With increasing concentration of AgNO 3 , the particle shape changes from triangular to spherical. In the presence of CuSO 4 , triangular plates with side lengths and tips that are longer and sharper, respectively, than those of the nanoplates prepared in the absence of CuSO 4 , are obtained.Metal nanoparticles show unique electronic and optical properties that are different from those of bulk metals, and their properties are dependent on their shapes and sizes.15 Silver and gold triangular nanoparticles (triangular nanoprisms and nanoplates) display interesting localized surface plasmon resonances. 615 The electromagnetic field is strongly enhanced around their tips. Furthermore, when two or more triangular particles meet, the enhancement is magnified and is expected to significantly affect spectral properties such as surface-enhanced Raman scattering 1618 Recently, we have reported the synthesis methods of gold triangular nanoplates. 31 The addition of Ag + ions, halide ions, and other chemicals are expected to control the shape and size of nanoparticles. In this paper, we want to report about the effects of adding AgNO 3 and CuSO 4 on the shape and size of gold nanoparticles prepared by the tartaric acid reduction method.The gold nanoparticles were prepared by modifications of the method reported elsewhere. 31 The solutions containing 0.5 mM (1 M = 1 mol dm ¹3 ) HAuCl 4 , 2.2 mM hexadecyltrimethylammonium chloride (HTACl) as a protective agent, and 60 mM tartaric acid (H 2 tart) as a reducing agent in the absence and presence of AgNO 3 and CuSO 4 were placed in an oil bath kept at 30°C. After 10 min, the bath temperature was increased to 70°C; subsequently, reactions took place for 13 min, after which the solutions were taken out of the bath and aged overnight. Transmission electron microscope (TEM) observations were performed using a Hitachi H-8100 TEM with an acceleration voltage of 200 kV. Extinction spectra were measured using a Hitachi U-2800 spectrophotometer.The extinction spectra for gold nanoparticles prepared in the absence and the presence of AgNO 3 and CuSO 4 are shown in Figure 1. The gold nanoparticles prepared in the absence of AgNO 3 and CuSO 4 show a peak at 550 nm and a tail extending up to 800 nm. Figure 2 shows the TEM images for triangular nanoplates having a side length of 54 nm. Each triangular nanoplate is a gold single crystal with the (111) main face.31 The adsorptions of Cl ¹ ions on the (111) facets were proposed to promote the growth of the {111} oriented triangular particles prepared by citrate reduction (Turkevich method) in the presence of KCl with a KCl/AuCl 4 ¹ molar ratio of 1. 23 In our case, adsorption of HTACl molecules on the (111) facets promotes the growth of the h111i oriented triangular nanoplates.In the presence of AgNO 3 , the extinction peak wavelengths for the obtained gold ...

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The Role of Bromide Ions in Seeding Growth of Au Nanorods

Cited by 136 publications

References 45 publications

Short Gold Nanorod Growth Revisited: The Critical Role of the Bromide Counterion

Short Gold Nanorod Growth Revisited: The Critical Role of the Bromide Counterion

Seed-mediated synthesis of gold nanorods: control of the aspect ratio by variation of the reducing agent

Effects of Ag+ and Cu2+ Ions on the Shape of Triangular Gold Nanoparticles

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