Tuning the Morphology of Au/CdS Nanocomposites through Temperature-Controlled Reduction of Gold-Oleate Complexes

Khon, Elena; Hewa-Kasakarage, Nishshanka N.; Nemitz, Ian R.; Acharya, Krishna Prasad; Zamkov, Mikhail

doi:10.1021/cm101922m

Cited by 43 publications

(59 citation statements)

References 40 publications

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“…Au NCs were synthesized using a one-pot procedure developed in our group. 12 In a typical synthesis, 0.011 g of AuCl 3 was placed in a one-neck flask and dissolved in 3 mL of oleylamine by 10À15 min of sonication. This reaction mixture was orange in color when the Au salt was dissolved in oleylamine, indicating a formation of AuÀoleate complexes.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Lifetime of Excitons in Nonepitaxial Au/CdS Core/Shell Nanocrystals

et al. 2013

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The ability of metal nanoparticles to capture light through plasmon excitations offers an opportunity for enhancing the optical absorption of plasmon-coupled semiconductor materials via energy transfer. This process, however, requires that the semiconductor component is electrically insulated to prevent a "backward" charge flow into metal and interfacial states, which causes a premature dissociation of excitons. Here we demonstrate that such an energy exchange can be achieved on the nanoscale by using nonepitaxial Au/CdS core/shell nanocomposites. These materials are fabricated via a multistep cation exchange reaction, which decouples metal and semiconductor phases leading to fewer interfacial defects. Ultrafast transient absorption measurements confirm that the lifetime of excitons in the CdS shell (τ ≈ 300 ps) is much longer than lifetimes of excitons in conventional, reduction-grown Au/CdS heteronanostructures. As a result, the energy of metal nanoparticles can be efficiently utilized by the semiconductor component without undergoing significant nonradiative energy losses, an important property for catalytic or photovoltaic applications. The reduced rate of exciton dissociation in the CdS domain of Au/CdS nanocomposites was attributed to the nonepitaxial nature of Au/CdS interfaces associated with low defect density and a high potential barrier of the interstitial phase.

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Section: Methodsmentioning

confidence: 99%

Enhanced Lifetime of Excitons in Nonepitaxial Au/CdS Core/Shell Nanocrystals

et al. 2013

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“…[1][2][3][4][5][6][7][8][9][10][11][12] In particular, semiconductor nanowires (NWs) with high aspect ratio are particularly attractive for use in photocatalysis because their onedimensional structure offers large surface areas, high carrier mobility along the nanowires, markedly enhanced light absorption and scattering, and chemical and physical stability. An excellent solution to this problem is to inject metals [29][30][31][32][33][34][35][36][37] (Au, Pd, Pt, Ni, etc.) An excellent solution to this problem is to inject metals [29][30][31][32][33][34][35][36][37] (Au, Pd, Pt, Ni, etc.)…”

Section: Introductionmentioning

confidence: 99%

Efficient electrostatic self-assembly of one-dimensional CdS–Au nanocomposites with enhanced photoactivity, not the surface plasmon resonance effect

Liu

2013

Nanoscale

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A series of CdS nanowire-Au nanocomposites (CdS NW-Au NCs) with different weight addition ratios of Au nanoparticles (NPs) are successfully synthesized by using a simple and efficient electrostatic self-assembly method at room temperature for utilizing the natural surface charge properties of the CdS NWs and Au NPs. These natural surface charge properties are dependent on the synthesis approaches. The probe reactions for photocatalytic selective reduction of nitroaromatic compounds in the aqueous phase under visible light irradiation are utilized to evaluate the photoactivity of this series of as-prepared CdS NW-Au NCs. The CdS NW-Au NCs exhibit significantly enhanced photoactivity as compared to the CdS nanowires (CdS NWs). The addition of Au NPs into the CdS NW domain enables efficient enhancement of the lifetime and transfer of photogenerated charge carriers from CdS NWs under visible light irradiation. However, the addition of excess amounts of Au NPs not only influences the penetration of light but the Au NPs also become the recombination centers, and result in decreased photoactivity. The optimal proportion of the Au NPs is proved to be 1 wt%, which indicates the synergistic effect between the CdS NWs and Au NPs. In addition, the surface plasmon resonance (SPR) effect of Au NPs is proved to not play an efficient role in the reaction and the possible photocatalytic reaction mechanism is proposed. It is hoped that this work could aid in the fabrication of 1-D semiconductor-metal nanocomposites by using such a simple and efficient electrostatic self-assembly strategy. In addition, it is also expected to enrich and supplement their application as visible light photocatalysts toward selective organic transformations through our investigation.

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“…As well know, the hexagonal crystal structured seeds forms a diverse group of 1D nanostructures because of the wurtzite structural characteristics of the fastest growth directions and polar surfaces. 21 In the case of CdS seeds, CdS nanorods were first formed by growing CdS linear extensions from (000 ± 1) facets of small-diameter CdS seeds. CdS nanowires with a single-crystal wurtzite structure and grown along the [0001] (c-axis) were further created through further controlling the growth process.…”

Section: Characteristicsmentioning

confidence: 99%

“…CdS has been used to create various 1D heterostructures 20 Khon and co-workers reported on the colloidal growth of Au nanoparticles (NPs) with precisely diameters from 2.5 to 16 nm on the surface of CdS nanomaterials to get composited heterostructures, whereas the shape of Au/CdS nanocomposites can be controllably switched between matchsticks and barbells via the reaction rate. 21 Banin's group explored the growth mechanism of gold NPs onto preformed cadmium sulfide nanorods to form hybrid metal nanocrystal/semiconductor nanorod colloids. 22 They fabricated nanostructures exhibiting Au nanocrystal growth at only one nanorod tip, at both tips, or at multiple locations along the nanorod surface.…”

Section: Introductionmentioning

confidence: 99%

CdS Nanowires with Large Aspect Ratio and Their Composite with CuS and Au Nanoparticles

Yang

Jiang

Miao

et al. 2016

j nanosci nanotechnol

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We prepared CdS nanowires with small diameter (2.9 nm) and a large aspect ratio (more than 60) via a seed growth method. Wurtzite CdS seeds were firstly obtained via an organic synthesis at 310 degrees C. CdS nanowires with a single-crystal wurtzite structure and grown along the [0001] (c-axis) were further created through controlling the growth process. The injection of precursors plays an important role for getting a large respect ratio. The average size of the seeds is 2.9 nm. The growth along c-axis occurred during the preparation of the nanowires. The diameter of 2.9 nm remained unchanged within short reaction time. The heterostructures of the nanowires were fabricated by depositing CuS and Au nanoparticles (NPs). CuS monomers firstly deposited on the top of the nanowire and then to form a CuS shell on the top. In contrast, Au NPs deposited firstly on the top part of the nanowire. With increasing time or the amount of precursors, small Au NPs on side part of the nanowire was observed. The possible deposition kinetics was discussed. Because of homogeneous and uniform morphology, the heterostructures may be utilizable for applications.

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Tuning the Morphology of Au/CdS Nanocomposites through Temperature-Controlled Reduction of Gold-Oleate Complexes

Cited by 43 publications

References 40 publications

Enhanced Lifetime of Excitons in Nonepitaxial Au/CdS Core/Shell Nanocrystals

Enhanced Lifetime of Excitons in Nonepitaxial Au/CdS Core/Shell Nanocrystals

Efficient electrostatic self-assembly of one-dimensional CdS–Au nanocomposites with enhanced photoactivity, not the surface plasmon resonance effect

CdS Nanowires with Large Aspect Ratio and Their Composite with CuS and Au Nanoparticles

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