General Shape Control of Colloidal CdS, CdSe, CdTe Quantum Rods and Quantum Rod Heterostructures

Shieh, Felice; Saunders, Aaron E.; Korgel, Brian A.

doi:10.1021/jp0509008

Cited by 320 publications

(361 citation statements)

References 31 publications

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“…1b,c) followed by selective growth of CdSe at the tips (Fig. 1d,e) much like the barbell or rod/rod/rod shaped type II nanorod heterostructures of CdTe/CdSe/CdTe that have been reported previously 13,14,36 . The key distinction and thus the main challenge here is the selective growth of the third component, ZnSe.…”

Section: Challenges In Synthesissupporting

confidence: 64%

“…Synthesis of CdS nanorods. CdS nanorods were prepared in a manner similar to established methods 14 . The reactions were carried out in a standard Schlenk line under N 2 atmosphere.…”

Section: Discussionmentioning

confidence: 99%

“…Recent advances in the synthesis of multicomponent semiconductor nanocrystals with anisotropic shapes/ morphologies [25][26][27][28][29][30] provide a potential solution. When combined with band alignment/band gap engineering of semiconductor heterostructures, anisotropic nanorods can also provide control over both spatial and electronic directionality and accessibility [12][13][14][15]31,32 (for example, for efficient charge injection/extraction). However, to achieve our envisioned DHNRs, there are additional difficulties.…”

Section: Challenges In Synthesismentioning

confidence: 99%

“…In particular, core/shell heterostructures with type I straddling band offset exhibiting high photoluminescence (PL) quantum yields show much promise in imaging 3 , lighting 4,5 and display [6][7][8][9][10][11] applications. Although type II staggered band offset materials have also been achieved and have been shown to allow efficient photoinduced charge separation [12][13][14][15][16] and improved light amplification 17,18 , to date, the highly luminescent type I core/shell heterostructure is the predominant choice in emerging nanocrystal-based products. However, the type I core/shell structure may be less than ideal especially in photovoltaics, optoelectronics and related device applications in that the large band gap shell prohibits physical access to the core and poses a significant barrier for carrier injection and extraction 19 .…”

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confidence: 99%

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Double-heterojunction nanorods

et al. 2014

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As semiconductor heterostructures play critical roles in today's electronics and optoelectronics, the introduction of active heterojunctions can impart new and improved capabilities that will enable the use of solution-processable colloidal quantum dots in future devices. Such heterojunctions incorporated into colloidal nanorods may be especially promising, since the inherent shape anisotropy can provide additional benefits of directionality and accessibility in band structure engineering and assembly. Here we develop doubleheterojunction nanorods where two distinct semiconductor materials with type II staggered band offset are both in contact with one smaller band gap material. The double heterojunction can provide independent control over the electron and hole injection/ extraction processes while maintaining high photoluminescence yields. Light-emitting diodes utilizing double-heterojunction nanorods as the electroluminescent layer are demonstrated with low threshold voltage, narrow bandwidth and high efficiencies.

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Section: Challenges In Synthesissupporting

confidence: 64%

“…Synthesis of CdS nanorods. CdS nanorods were prepared in a manner similar to established methods 14 . The reactions were carried out in a standard Schlenk line under N 2 atmosphere.…”

Section: Discussionmentioning

confidence: 99%

Section: Challenges In Synthesismentioning

confidence: 99%

mentioning

confidence: 99%

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Double-heterojunction nanorods

et al. 2014

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“…[10][11][12][13][14] In general over the last decade much attention has been directed towards II-VI type CdS, CdTe and CdSe quantum dots (QDs). [15][16][17][18][19] It is the ability to fine-tune their optical properties by chemical control of their size and shape (i.e. their degree of quantum confinement) which makes quantum dots particularly interesting.…”

Section: Graphical Abstract: Introductionmentioning

confidence: 99%

Synthesis and spectroscopic studies of chiral CdSe quantum dots

et al. 2010

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Using microwave irradiation, water soluble, optically active, penicillamine (Pen) capped CdSe nanocrystals with broad spectral distribution (430-780 nm) of photoluminescence have been produced and studied by a range of instrumental techniques including absorption, circular dichroism and both steady state and time resolved photoluminescence spectroscopy. The photoluminescence of these nanocrystals is attributed to emission from surface defect states. The decay of the excited state in the nanosecond region, which can be analysed as a triple exponential, depends strongly on the emission wavelength selected, but only weakly on the excitation wavelength. Graphical Abstract: IntroductionChirality is a common occurrence in the natural world and chiraln compounds are very important in chemistry, biology, pharmacology and medicine. It has also been envisaged that chirality could play an important role in nanotechnology. 1,2 The majority of existing research in this field has been focused on chiral organic, metallorganic and biological molecules and their supramolecular structures, 3 while research in the area of chiral inorganic nanoparticles is still in the very early stage of its development. For example, there has been some work involving chiral optically active metallic gold 4,5 and silver 6,7 nanoparticles, as well as carbon nanotubes. 8,9 However, there are currently only a few recent papers dealing with chiral light emitting semiconducting nanocrystals (quantum dots). [10][11][12][13][14] In general over the last decade much attention has been directed towards II-VI type CdS, CdTe and CdSe quantum dots (QDs). [15][16][17][18][19] It is the ability to fine-tune their optical properties by chemical control of their size and shape (i.e. their degree of quantum confinement) which makes quantum dots particularly interesting. This level of optical control combined with QDs' resistance to photobleaching and their high level of solubility in practically any solvent (depending on the stabiliser used) make these nanomaterials potentially suited for roles as divergent as light emitting diodes, 20 biological sensors 21 and photovoltaic devices. [22][23][24] Thiol group containing amino acids have proved to be excellent stabilisers, with L-cysteine becoming one of the popular surface capping molecules for CdX (X ¼ S, Se, and Te) nanoparticles. 18,[25][26][27][28][29][30][31] In addition this use of stereospecific chiral stabilising molecules opened another avenue of interest in the area of quantum dot research, as chirality is a key factor in biological and biochemical interactions. Due to their unique photophysical properties, we believe that chiral QDs have a range of potential applications in photonics and biochemistry. 13,32,33 The main aim of our work is to develop novel chiral CdSe based QDs by using chiral stabilisers and to investigate the properties of these materials. Here we report the synthesis and detailed spectroscopic studies of new penicillamine stabilised CdSe QDs, which have been prepared using the dextrorota...

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Semiconductor Nanowires

Korgel

2005

Encyclopedia of Inorganic Chemistry

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This review provides an overview of the synthesis, structural and chemical properties, and assembly and processing strategies of semiconductor nanowires. Vapor–liquid–solid (VLS), solution–liquid–solid (SLS), supercritical fluid–liquid–solid (SFLS) approaches that rely on the formation of a liquid metal–semiconductor eutectic to seed nanowire growth are covered. Nanowire growth from metal seed particles in the solid phase are also discussed, as well as chemical methods that rely on surfactants, self‐assembly, and directed crystallization processes. Structural details about the nanowires, including the crystallographic growth direction, common extended defects, and surface faceting are discussed. Routes to surface passivation by organic monolayers and compositional control of impurity doping and heterostructures—radial and axial—are presented, as well as more structurally complicated branched nanowire structures. Finally, an overview of nanowire processing and manipulation is offered, with a discussion about positioned growth, self‐assembly, and the potential impact of impurities on applications.

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General Shape Control of Colloidal CdS, CdSe, CdTe Quantum Rods and Quantum Rod Heterostructures

Cited by 320 publications

References 31 publications

Double-heterojunction nanorods

Double-heterojunction nanorods

Synthesis and spectroscopic studies of chiral CdSe quantum dots

Semiconductor Nanowires

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