Synthesis and Optical Properties of Water-Soluble CdTe:Zn2+ Quantum Dots Prepared by the One-Pot Approach

Sousa, José C. L.; Vivas, Marcelo G.; Ferrari, Jefferson Luis; Schiavon, Marco A.

doi:10.21577/0103-5053.20180128

Cited by 4 publications

(7 citation statements)

References 41 publications

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“…1,2 Good examples are composed of binary combinations of these atoms forming nanocrystals, such as CdTe or ZnSe QDs (II-VI group), InP QDs (III-V group), or PbSe QDs (IV-VI group). 8,9 Lately, new types of copper-based ternary and quaternary multicomponent QDs have also been prepared, as they have more environmental friendly compositions and show near-infrared emission profiles. Examples of ternary and quaternary nanocrystals include Cu−In−S (CIS), Cu−In−Se (CISe), Cu−Zn−In−S (CZIS), Zn−Ag−In−Se (ZAISe) and Zn−Ag−In−S (ZAIS).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, in order to reduce the nonradiative recombination sites, the nanocrystals are usually coated with a second semiconductor layer, usually of wider Eg, that passivates the surface, improving the luminescence efficiency and resulting in a core/shell structure (Figure 1c). 1,2,9,13 A representative transmission electron microscopy (TEM) of the nanocrystals is also presented in Figure 1d.…”

Section: Introductionmentioning

confidence: 99%

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(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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Quantum dots (QDs) are semiconductor nanocrystals, which present unique photophysical properties, enabling their application as new fluorescent platforms for biomedical sciences. Colloidal QDs are end-capped with organic or inorganic compounds, not only to prevent their agglomeration but also to provide reaction sites for the attachment of targeting (bio)molecules, nanoparticles or other interfaces, for specific biological purposes. The (bio)conjugation can involve non-covalent or covalent interactions, which can be accomplished through different strategies. The final assembly needs to maintain its chemical and optical stability and biochemical functionality. Although a relative good comprehension of the experimental procedures has been established, the bioconjugation process is still a challenge. The present manuscript aims to review the main (bio)conjugation strategies successfully applied to QDs, describing the steps necessary to prepare stable targeting fluorescent nanoplatforms, as well as some usual methods used to evaluate and optimize this process.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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“…Since OR-based growth has been strongly reported for systems of CdTe colloidal nanocrystals prepared from several synthesis methods, − we start the kinetic analysis of our growth data (Figure b, circles) trying to identify to what extent the curve ⟨ R ⟩ = ⟨ R ⟩( t ) is dominated by OR. Figure c shows this same growth curve replotted as ⟨ R ⟩ 3 versus time, indicating the existence of two different kinetic regimes during the considered time interval: a nonlinear region (I) in the very beginning of the synthesis (5 min-60 min) and a linear region (II) at longer times (75–180 min).…”

Section: Resultsmentioning

confidence: 99%

Combined Theoretical–Experimental Approach to the Growth Kinetics of Colloidal Semiconductor Nanocrystals

Ferreira

Silva

et al. 2019

J. Phys. Chem. C

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A new theoretical analytical model is proposed in order to provide a quantitative description of the growth kinetics of colloidal semiconductor nanocrystals. The temporal evolution of the mean size of the nanocrystal ensemble in solution was determined by monitoring the variation of the absorption and photoluminescence spectra in the course of the chemical synthesis and then submitting the resulting optical data to a calculation procedure that generated the corresponding time-evolving particle size distribution. Two main problems were addressed and properly correlated: the size-dependence of the bandgap transition for a single semiconductor nanocrystal, which was treated within the framework of the finite-depth square-well effective mass approximation, and the inhomogeneous broadening of the optical spectra due to the distribution of nanocrystal sizes and hence the distribution of bandgaps. By application of the reported methodology to CdTe nanocrystals synthesized through a one-pot aqueous chemical route, growth curves (mean particle size as a function of time) were calculated for syntheses performed under various initial experimental conditions. Such kinetic results were interpreted in the sense of the well-established classical crystallization theories based on homogeneous nucleation and growth of spherical particles in solution, including a detailed study on the Ostwald ripening process. Specific growth modes were identified along with numerical estimates for their characteristic rate constants. The presented calculation method is easy to implement, and it can be used to access the size evolution of solution-grown nanocrystals of many other semiconductor materials, regardless of the adopted preparation procedure.

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“…Semiconductor quantum dots (QDs) [1,2], whose size is less than the material Bohr exciton radius, have received more and more attention due to their size dependence and novel optical properties during the past decades. Their three-dimensions confined to the nanoscales with a size typically in the range of 1–10 nm [1,3]. Unlike bulk materials, they have unique optical and electronic properties including wide excitation spectra, narrow symmetric and tunable emission spectra.…”

Section: Introductionmentioning

confidence: 99%

L-Aspartic Acid Capped CdS Quantum Dots as a High Performance Fluorescence Assay for Sliver Ions (I) Detection

et al. 2019

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A new high performance fluorescence assay for detection of Ag+ based on CdS quantum dots (QDs) using L-Aspartic acid (L-Asp) as a stabilizer was proposed in this work. The CdS quantum dots conjugation with L-Aspartic acid (L-Asp@CdS QDs) were successfully synthesized via a simple hydrothermal process. The QDs have a fluorescence emission band maximum at 595 nm with a quantum yield of 11%. The obtained CdS QDs exhibit a particle size of 1.63 ± 0.28 nm and look like quantum dot flowers. Basically, the fluorescence intensity of L-Asp@CdS QDs can be enhanced only upon addition of Ag+ and a redshift in the fluorescence spectrum was observed. Under optimum conditions, the fluorescence enhancement of L-Asp@CdS QDs appeared to exhibit a good linear relationship in between 100–7000 nM (R2 = 0.9945) with the Ag+ concentration, with a detection limit of 39 nM. The results indicated that the L-Asp@CdS QDs were well used in detection for Ag+ as fluorescence probe in aqueous solution with high sensitivity and selectivity. Moreover, the sensing system has been applied in detection Ag+ in real water samples. The recovery test results were 98.6%~113%, and relative standard deviation (n = 5) is less than 3.6%, which was satisfactory.

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Synthesis and Optical Properties of Water-Soluble CdTe:Zn2+ Quantum Dots Prepared by the One-Pot Approach

Cited by 4 publications

References 41 publications

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Combined Theoretical–Experimental Approach to the Growth Kinetics of Colloidal Semiconductor Nanocrystals

L-Aspartic Acid Capped CdS Quantum Dots as a High Performance Fluorescence Assay for Sliver Ions (I) Detection

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