Generalized Synthesis of Hybrid Metal–Semiconductor Nanostructures Tunable from the Visible to the Infrared

Khanal, Bishnu P.; Pandey, Anshu; Li, Liang; Lin, Qianglu; Bae, Wan Ki; Luo, Hongmei; Klimov, Victor I.; Pietryga, Jeffrey M.

doi:10.1021/nn204932m

Cited by 99 publications

(97 citation statements)

References 60 publications

(94 reference statements)

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“…69 However, when these NPs are interacting with the nearby environment, as is inevitable in device applications, their intrinsic properties diverges from that of free particles and depends critically on the chemical composition and electronic properties of the adjacent materials. 70 In the present experiment, it is seen that the band gap of ZnO QDs could be varied upon adsorption onto the size-specific gold nanoparticles. The mechanism of tuning the band gap can be explained by the nature and extent of interaction between the ZnO QDs and Au NPs of different sizes in the composites.…”

Section: Scheme 1 Schematic Presentation Of Miniaturizing the Band Gmentioning

confidence: 48%

Manipulating Electron Transfer in Hybrid ZnO–Au Nanostructures: Size of Gold Matters

Rahman

Ghosh

2016

J. Phys. Chem. C

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Hybrid semiconductor−plasmonic metal nanostructures (NSs) tailoring of zinc oxide−gold (ZnO−Au) have been synthesized by direct addition of an aliquot of ZnO quantum dots (QDs) to aqueous dispersions of gold nanoparticles (NPs) of five different sizes. Gold nanoparticles of variable sizes have been prepared by Frens' citrate reduction procedure and ZnO QDs by alkaline hydrolysis of zinc acetate dihydrate in methanol. The optical properties of hybrid ZnO− Au nanostructures have been explored by absorption, photoluminescence, and Raman spectroscopy; the intrinsic changes in the optical characteristics of the individual components reflect strong interfacial interaction between ZnO and Au nanostructures. The binding of ZnO QDs to the colloidal gold particles has further been elucidated by Fourier transform infrared spectroscopy and cyclic voltammetry measurements. The morphology and crystallinity of the ZnO−Au NSs have been characterized by transmission electron microscopy, high resolution transmission electron microscopy, selected area electron diffraction, and X-ray diffraction techniques. Absorption spectral studies have revealed that ZnO QDs attached on the size-specific Au NPs elicites the modification of band gap in hybrid semiconductor−metal nanostructures. The catalytic activities of the as-prepared ZnO−Au NSs consisting of gold nanoparticles of variable sizes have been probed by employing photochemical decomposition of Evans blue under visible light irradiation as the model reaction. Finally, the trends in the alteration of different interaction parameters in structuring hybrid semiconductor−metal nanostructures with the band gap have been correlated.

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Section: Scheme 1 Schematic Presentation Of Miniaturizing the Band Gmentioning

confidence: 48%

Manipulating Electron Transfer in Hybrid ZnO–Au Nanostructures: Size of Gold Matters

Rahman

Ghosh

2016

J. Phys. Chem. C

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“…28,31,35,36 Experimental reports on these variables are inconsistent and range from fluorescent enhancement 16,19,21,22,30,37À42 to quenching. 14,15,17,20,21,24,25,42,43 For instance, Peng et al 21 recently reported a systematic study showing that maximum enhancement and strongest quenching occurred at gaps of 21.9 and 2.8 nm, respectively, for spherical Au nanoparticle core surrounded by a shell of molecular dye, while Kulakovich et al observed maximum enhancement with an 11 nm gap between CdSe QD and a AuNP colloidal film. 22 Large nonspherical plasmonic particles, including rods, triangles, and discrete clusters, are of current interest due to their larger scattering crosssection and spatial focus of the near field of the localized SPR (LSPR).…”

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confidence: 99%

Large Scale Solution Assembly of Quantum Dot–Gold Nanorod Architectures with Plasmon Enhanced Fluorescence

et al. 2013

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Tailoring the efficiency of fluorescent emission via plasmon-exciton coupling requires structure control on a nanometer length scale using a high-yield fabrication route not achievable with current lithographic techniques. These systems can be fabricated using a bottom-up approach if problems of colloidal stability and low yield can be addressed. We report progress on this pathway with the assembly of quantum dots (emitter) on gold nanorods (plasmonic units) with precisely controlled spacing, quantum dot/nanorod ratio, and long-term colloidal stability, which enables the purification and encapsulation of the assembled architecture in a protective silica shell. Overall, such controllability with nanometer precision allows one to synthesize stable, complex architectures at large volume in a rational and controllable manner. The assembled architectures demonstrate photoluminescent enhancement (5×) useful for applications ranging from biological sensing to advanced optical communication.

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“…Silica templates provide a more controlled route towards achieving the same end. Khanal et al [23] were able to demonstrate significant increases in the two-photon cross-sections of NCs that were tethered to functionalized gold-coated silica templates. Cross-sections as high as 4 × 10 5 Goeppert-Meyer that were observed in this work [23] are among the highest observed in colloidal NCs.…”

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confidence: 99%

“…Khanal et al [23] were able to demonstrate significant increases in the two-photon cross-sections of NCs that were tethered to functionalized gold-coated silica templates. Cross-sections as high as 4 × 10 5 Goeppert-Meyer that were observed in this work [23] are among the highest observed in colloidal NCs. The enhanced cross-sections correlate with the field enhancements expected in the near-field of metallic nanoparticles.…”

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confidence: 99%

Recent advances in the preparation of nanocrystal solids

2015

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Colloidal chemistry offers several tools to synthesize and manipulate nanoscopic objects. Despite the existence of a plethora of tools to design building blocks, methods for assembling these components into functional macroscopic materials are still in their infancy. This review discusses the recent progress made towards assembling rudimentary nanoscale building blocks into functional macroscopic materials.Colloidal nanocrystals (NCs) are well known because of their emission tunability [1]. Additionally, these materials exhibit exceptionally high quantum yields and photostability in colloidal solution [2,3]. Luminescence is however only one among several intriguing properties exhibited by these materials. In fairly general terms, the unique properties of colloidal NCs arise from two different sources. Quantum confinement [4,5] acts differently and to a varied extent on the several excitations within a NC. Quantum confinement manifests itself through a change of the density of states. The magnitude of this effect is different for various excitations, as each excitation samples distinct characteristic volumes of a material [6]. NCs therefore end up with vastly different physical properties compared to bulk materials. The other key influence on NC properties comes from the flexibility afforded by colloidal chemistry. Colloidal techniques enable the synthesis and manipulation of materials with a host of functionalities: Semiconductors [1], metals [7][8][9][10][11], semimetals [12], superconductors [13,14], thermoelectrics [15], etc. For example, figure 1 shows a host of metallic as well as semiconductor NCs synthesized using colloidal techniques [16]. Structures as diverse as platelets, nanorods, bipyramids, core/shell architectures, etc. may be prepared by varying the reaction conditions, surfactants or both [11,[17][18][19]. While nanostructuring modifies the physical properties of individual materials [20], colloidal chemistry opens up the additional possibility of combining rudimentary building blocks into materials with counterintuitive dual functionalities. For example, Pramana -J. Phys.

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Generalized Synthesis of Hybrid Metal–Semiconductor Nanostructures Tunable from the Visible to the Infrared

Cited by 99 publications

References 60 publications

Manipulating Electron Transfer in Hybrid ZnO–Au Nanostructures: Size of Gold Matters

Manipulating Electron Transfer in Hybrid ZnO–Au Nanostructures: Size of Gold Matters

Large Scale Solution Assembly of Quantum Dot–Gold Nanorod Architectures with Plasmon Enhanced Fluorescence

Recent advances in the preparation of nanocrystal solids

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