Synthesis, structure and spectroscopic characterization of water-soluble CdS nanoparticles

Barglik-Chory, Ch.; Buchold, Daniel H. M.; Schmitt, Michael; Kiefer, W.; Heske, Clemens; Kumpf, Christian; Fuchs, O.; Weinhardt, L.; Stahl, Andreas; Umbach, E.; Lentze, Michael J.; Geurts, J.; Müller, Gerd

doi:10.1016/j.cplett.2003.08.068

Cited by 58 publications

(24 citation statements)

References 30 publications

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“…[12] Glutathione has also been directly used as a capping agent for ZnS [13] and CdS QDs, [14] however, their fluorescence spectra were dominated by a broad trap emission band. Baumle et al examined glutathione-capped CdSe QDs, which have a single fluorescence color at 533 nm and a moderate QY of 16 %.…”

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confidence: 99%

Synthesis and Cell‐Imaging Applications of Glutathione‐Capped CdTe Quantum Dots

2007

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Quantum dots (QDs) are of great interest to biological applications such as fluorescent biosensors and biolabels. Our study describes a synthesis of glutathione-capped CdTe QDs in aqueous solution that is cost-efficient and convenient compared to the conventional organometallic approaches. The fluorescence of the as-prepared glutathione-capped CdTe QDs was tunable from 500 to 650 nm. Without any postpreparation treatment, the glutathione-capped CdTe QDs achieved quantum yields (QYs) as high as 45 %, comparable to, or even better than, QDs derived from organometallic routes. With an overall size as small as 4 nm, they could gain access to cellular targets and stain fine features such as the cell nucleolus. These QDs were successfully conjugated with biotin for immunostaining and with F3 peptide for delivery to live cells, demonstrating their potentially broad application as biolabels.Fluorescent semiconductor nanoparticles or QDs have been extensively investigated in the past decade, and have been widely used as biolabels in imaging and biodetection.[1] Fluorescence imaging can greatly benefit from the use of QDs, which show brighter fluorescence, less photobleaching, and multiple colors with a single excitation. For biolabeling applications, QDs are commonly capped with trioctylphosphine oxide (TOPO) through organometallic synthesis, followed by phospholipid, [2] silica, [3] or polymer [4] coating to impart watersolubility and biocompatibility. With the multilayer coating, the final size of the QD biolabels would typically be 12-20 nm, which might be too bulky to gain access to cells for in vitro and in vivo imaging. In addition, the large dimensions would dramatically lower the labeling efficiency on specific target sites within the cells. Compared to conventionally used organic dyes, the size of QDs presented a major drawback as it limited the range of applications in biolabeling. To overcome this obstacle, water-soluble QDs with only one layer of capping ligand on the surface have been developed by ligand exchange with thiols [5] or phosphine [6] on TOPO-capped QDs.Both the ligand-addition and ligand-exchange methods were complicated, and even the high-quality QDs derived from organometallic methods have exhibited reductions in QY from 65-85 % in the organic phase to 35-50 % in aqueous solution.[7]Alternatively, thiol-capped QDs could be prepared directly in aqueous solution with thiols as stabilizers, but low QYs of 1-10 % were typically obtained.[8] Although their QYs could be significantly improved by a variety of after-treatments, such as photochemical etching, [8] size-selective precipitation, [9] and long-term illumination, [10] these QDs have a tendency to agglomerate during such treatments. Glutathione is a thiol-containing oligopeptide found in most organisms, and it plays an important role in the detoxification of heavy metals in plant cells. The physiological mechanism of detoxification involves the binding of heavy-metal nanoclusters by glutathione and the formation of a phytochelatin shell, cat...

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confidence: 99%

Synthesis and Cell‐Imaging Applications of Glutathione‐Capped CdTe Quantum Dots

2007

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“…2.5 H 2 O with the CdS core 1.3 nm in diameter and a shell 0.5 nm thick exhibit a blue shift of the absorption band and a shift of the luminescence band at 550 nm. 98 Similar changes in the photoluminescence and optical absorption are also characteristic of thin films prepared by aqueous solution deposition. 99 The band gap in the films annealed at 450 8C decreased from 3.50 to 3.46 eV, while the particle size increased from 2.60 to 2.64 nm.…”

Section: Iii4 Photoluminescencementioning

confidence: 69%

Cadmium sulfide nanoparticles prepared by chemical bath deposition

Кожевникова¹,

Ворох²,

Uritskaya³

2015

Russ. Chem. Rev.

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“…By using PVP with an average molar mass of 10 kg/mol (Fluka), the center to center distance of the particles is adjusted to 9 nm. Therefore, any interaction between the QD on the silica colloid can be excluded [11]. This can be proven by photoluminescence spectroscopy, which shows that the emission band of the QD remains unchanged before and after the coupling to the silica surface.…”

Section: Nanoparticlesmentioning

confidence: 96%

“…Doping these systems with Cu, Fe, or Mn atoms also affects the electronic structure of CdSe and ZnSe QD [8][9][10]. Further, soft X-ray emission spectroscopy has been used for the characterization of the nature of bonding between the surface atoms of QD and stabilizing organic molecules [11,12], the core shell structure [13][14][15] as well as the surface oxidation [16] of II-VI and III-V semiconductor nanoparticles. These experiments give detailed information on the electronic properties of the nanoparticles, especially interior and surface states.…”

Section: Introductionmentioning

confidence: 99%

Experiments on single levitated particles: a novel approach for investigations of electronic properties of structured II‐VI‐semiconductor nanoparticles in selected environments

Gräf

Lewinski

Dembski

et al. 2007

Phys. Status Solidi (c)

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A novel approach for investigations of the electronic structure of II-VI semiconductor nanoparticles in selected environments is presented. CdSe/ZnS core shell nanoparticles are dispersed in a liquid non-volatile siloxane graft/block copolymer and injected in an electrodynamic trap, where a single liquid microdroplet is stably stored under ultra high vacuum conditions. In this way, it is possible to investigate quantum dots by soft X-ray spectroscopies in a liquid environment, which is not influenced by any outer surface. NEXAFS spectra of stored nanoparticles were recorded at the Zn 2p-, S 2p-, and Cd 3d-edge by measuring X-ray excited optical luminescence or the element-selective charging current of single, trapped microdroplets. The spectra are compared to those of similar CdSe/ZnS nanoparticles, which are dispersed in a controlled way in solid silica colloids as well as to those of matrix materials. An analysis of the data reveals that the electronic structure of the ZnS shell is significantly influenced by the outer functionalization and the dispersive media whereas the electronic structure of the core is shown to be independent from the surroundings.

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Synthesis, structure and spectroscopic characterization of water-soluble CdS nanoparticles

Cited by 58 publications

References 30 publications

Synthesis and Cell‐Imaging Applications of Glutathione‐Capped CdTe Quantum Dots

Synthesis and Cell‐Imaging Applications of Glutathione‐Capped CdTe Quantum Dots

Cadmium sulfide nanoparticles prepared by chemical bath deposition

Experiments on single levitated particles: a novel approach for investigations of electronic properties of structured II‐VI‐semiconductor nanoparticles in selected environments

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