Coupled Composite CdS−CdSe and Core−Shell Types of (CdS)CdSe and (CdSe)CdS Nanoparticles

Tian, Yantao; Newton, Theresa A.; Kotov, Nicholas A.; Guldi, and Dirk M.; Fendler, János H.

doi:10.1021/jp951965l

Cited by 236 publications

(150 citation statements)

References 36 publications

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“…the nominal-flow concentration of H 2 S is increased), the peak intensity of the band-gap emission shifts to higher values (lower energy) with a corresponding increase in absolute intensity observed. Similar observations have been reported for co-precipitated CdSCdSe core-shell nanoparticles upon the addition of H 2 S:H 2 Se gases [27]. The band-gap energy, E dir g , is also observed (Fig.…”

Section: +supporting

confidence: 87%

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Surfactant-mediated variation of band-edge emission in CdS nanocomposites

O’Dwyer¹,

Lavayen²,

Mirabal³

et al. 2007

Photonics and Nanostructures - Fundamentals and Applications

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Section: +supporting

confidence: 87%

“…Pre- vious observations with other CdS-containing compounds [27,28,16,17] have attributed the broad-band emission they observed at ∼670 nm to the recombination of trapped carriers (holes). Cadmium ions (Cd 2+ ) are known to activate the excitonic emission of colloidal CdS particles in a highly media-dependent fashion [33].…”

Section: +mentioning

confidence: 93%

Surfactant-mediated variation of band-edge emission in CdS nanocomposites

O’Dwyer¹,

Lavayen²,

Mirabal³

et al. 2007

Photonics and Nanostructures - Fundamentals and Applications

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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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“…Best fluorescence efficiency is obtained with semiconductor nanoparticles and semiconductor quantum dots based on sulfides, selenides, or tellurides. [8,9] The best-described fluorescent nanoparticles are GaN [10,11], doped ZnS [12], or doped CdSe. [13] All of these particles have the disadvantage of being as well poisonous as carcinogenic.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence from Coated Oxide Nanoparticles

2001

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In many cases, coated nanoparticles behave like isolated ones. Using the microwave plasma process, it is possible to produce oxide nanoparticles with ceramic or polymer coating. Coating the particles has the additional advantage that by proper selection of the coating it is possible to suspend the particles in distilled water without using any colloid stabilizer. From quantum dots made of sulfides or selenides, it is well known from literature that fluorescence depends strongly on the coating of the kernels. In the case of CdSe, the kernels are coated with CdS. Within this study, similar phenomena are found with coated oxide nanoparticles having sizes of ca. 6 nm exhibiting a very narrow particle size distribution. The coating consists of a second ceramic phase or a polymer one, each one influencing fluorescence differently. Obviously, the type of coating is a tool to modify fluorescence. This behavior is demonstrated on kernels made of A1 2 0 3 , ZrO 2 , HfO 2 , ZnO etc. PMMA, PTFE, or A1 2 0 3 were used as coating material. In most cases, the fluorescence spectra showed broad bands. In some cases, such as ZnO, additionally, a sharp emission line in the UV appears. It is interesting to note that coatings made of fluorine containing polymer materials did not lead to fluorescence intensities comparable with PMMA coatings. The observed spectra are equivalent whether the powder is in aqueous suspensions or dry on a quartz glass carrier. The experimental results in this study indicate that the combination of non-fluorescent oxide core with a non-fluorescent polymer coating may lead to a nanocomposite with strong fluorescence. This is a phenomenon not described in literature until now.

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Coupled Composite CdS−CdSe and Core−Shell Types of (CdS)CdSe and (CdSe)CdS Nanoparticles

Cited by 236 publications

References 36 publications

Surfactant-mediated variation of band-edge emission in CdS nanocomposites

Surfactant-mediated variation of band-edge emission in CdS nanocomposites

Synthesis and spectroscopic studies of chiral CdSe quantum dots

Fluorescence from Coated Oxide Nanoparticles

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