Review: three synthesis methods of CdX (X = Se, S or Te) quantum dots

Farkhani, Samad Mussa; Valizadeh, Alireza

doi:10.1049/iet-nbt.2012.0028

Cited by 85 publications

(52 citation statements)

References 174 publications

(188 reference statements)

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“…Its capping with a thin shell of cadmium sulfide (CdS), derived from stabilizing agents containing a thiol functional group (R-SH) or other materials, is widely used as a way of improving photoluminescence efficiency and photostability, shielding the exciton from surface defects and charge fluctuations in the vicinity of a bare nanocrystal [3][4][5][6][7][8]. Capping with CdS has also been shown to improve biocompatibility [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Dynamics of Photoluminescence Degradation in Aqueous CdTe/CdS Core-Shell Quantum Dots

Assis

et al. 2015

J Fluoresc

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We investigate the effects of the excitation power on the photoluminescence spectra of aqueous CdTe/CdS core-shell quantum dots. We have focused our efforts on nanoparticles that are drop-cast on a silicon nitride substrate and dried out. Under such conditions, the emission intensity of these nanocrystals decreases exponentially and the emission center wavelength shifts with the time under laser excitation, displaying a behavior that depends on the excitation power. In the low-power regime a blueshift occurs, which we attribute to photo-oxidation of the quantum dot core. The blueshift can be suppressed by performing the measurements in a nitrogen atmosphere. Under high-power excitation the nanoparticles thermally expand and aggregate, and a transition to a redshift regime is then observed in the photoluminescence spectra. No spectral changes are observed for nanocrystals dispersed in the solvent. Our results show a procedure that can be used to determine the optimal conditions for the use of a given set of colloidal quantum dots as light emitters for photonic crystal optical cavities.

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Section: Introductionmentioning

confidence: 99%

Characterization of the Dynamics of Photoluminescence Degradation in Aqueous CdTe/CdS Core-Shell Quantum Dots

Assis

et al. 2015

J Fluoresc

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“…Over the past two decades, cadmium chalcogenide QDs such as cadmium sulfide (CdS), cadmium selenide (CdSe), and cadmium telluride (CdTe) QDs have been extensively studied [29]. In particular, CdSe/ZnS (core/shell) QDs have been well-studied in terms of synthesis and its biological applications [30].…”

Section: Discussionmentioning

confidence: 99%

Targeted imaging and induction of apoptosis of drug-resistant hepatoma cells by miR-122-loaded graphene-InP nanocompounds

et al. 2017

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BackgroundCurrently, graphene oxide has attracted growing attention as a drug delivery system due to its unique characteristics. Furthermore, utilization of microRNAs as biomarkers and therapeutic strategies would be particularly attractive because of their biological mechanisms and relatively low toxicity. Therefore, we have developed functionalized nanocompounds consisted of graphene oxide, quantum dots and microRNA, which induced cancer cells apoptosis along with targeted imaging.ResultsIn the present study, we synthesized a kind of graphene-P-gp loaded with miR-122-InP@ZnS quantum dots nanocomposites (GPMQNs) that, in the presence of glutathione, provides controlled release of miR-122. The miR-122 actively targeted liver tumor cells and induced their apoptosis, including drug-resistant liver tumor cells. We also explored the near-infrared fluorescence and potential utility for targeting imaging of InP@ZnS quantum dots. To further understand the molecular mechanism of GPMQNs-induced apoptosis of drug-resistant HepG2/ADM hepatoma cells, the relevant apoptosis proteins and signal pathways were explored in vitro and in vivo. Furthermore, near-infrared GPMQNs, which exhibited reduced photon scattering and auto-fluorescence, were applied for tumor imaging in vivo to allow for deep tissue penetration and three-dimensional imaging.ConclusionIn conclusion, techniques using GPMQNs could provide a novel targeted treatment for liver cancer, which possessed properties of targeted imaging, low toxicity, and controlled release.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-016-0237-2) contains supplementary material, which is available to authorized users.

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“…Organometallic precursors comprise of metal alkyls or aryls (dimethylcadmium, diethylzinc, dibenzylmercury), whereas S, Se or Te sources are generally selected from trialkylphosphine chalcogenides (R 3 PSe, R 3 PTe with R ¼ octyl or butyl) or bistrimethylsilylchalcogenides e.g. (Me 3 Si) 2 S, abbreviated (TMS) 2 S. The selection of suitable solvent is important as it influences the reactivity of precursors as well as growth kinetics (Farkhani and Valizadeh 2014). The synthesis of most important type of QDs (II-VI semiconductors) consists of rapid injection of semiconductor precursor molecule into constantly stirred solvents like trioctylphosphine oxide (TOPO) or trioctylphosphine (TOP) as these solvents provide the most appropriate controlled conditions for the growth of nanocrystals (Hammer et al 2007).…”

Section: Chemical Reductionmentioning

confidence: 99%

Metallic Nanoparticles, Toxicity Issues and Applications in Medicine

Singla

Guliani

Kumari

et al. 2016

Nanoscale Materials in Targeted Drug Delivery, Theragnosis and Tissue Regeneration

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The metallic nanoparticles (NPs) and their synthetic biology are an active area fascinating both the academics as well as scientific research applications in the field of nanotechnology. These nanostructures are a versatile class of materials such as metal NPs, metal oxide NPs, magnetic NPs and quantum dots for biomedical sciences and engineering due to their huge potential. A handful number of methods are adopted for the synthesis of one or the other kind of metal NPs which includes physical and chemical approaches. Each of the chemical and physical synthesis procedures deals with some limitations such as cost ineffectiveness, use of hazardous chemicals, formation of toxic end products and involvement of high-energy processes. To overcome these drawbacks, an alternative approach of environmentally benign and inexpensive biological synthesis mediated by plants or microbes has been essentially adopted. The variations in size, shape and surface chemistry of NPs affect the properties of metal NPs to a greater extent which in turn have an influence on their biological behaviour. Few metal NPs offer unique optical properties while others possess paramagnetic behaviour and quantum size effect which make them suitable in bio-imaging diagnostic techniques. Some metallic NPs play a role in tissue engineering and other therapeutic applications due to their ease of surface modifications, large surface area to volume ratio, unique electrical and anti-microbial activities. Instead of multi-disciplinary applications of metallic NPs, there is a great concern regarding the toxicity issues associated with the use of these NPs which need to be sorted out by looking out certain ways for favourable architecture involving the synthesis methods and parameters for designing the non-toxic NPs for improving the quality of life.

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Review: three synthesis methods of CdX (X = Se, S or Te) quantum dots

Cited by 85 publications

References 174 publications

Characterization of the Dynamics of Photoluminescence Degradation in Aqueous CdTe/CdS Core-Shell Quantum Dots

Characterization of the Dynamics of Photoluminescence Degradation in Aqueous CdTe/CdS Core-Shell Quantum Dots

Targeted imaging and induction of apoptosis of drug-resistant hepatoma cells by miR-122-loaded graphene-InP nanocompounds

Metallic Nanoparticles, Toxicity Issues and Applications in Medicine

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