CdZnTe Quantum Dots Research Articles

Mercaptopropionic acid-capped CdZnTe Quantum dots as Fluorescence Probe for Sensitive Detection of Cr(III) ions.

Although Cr(III) ions are essential for the human body, excessive amounts can lead to skin inflammation, allergic reactions, and genotoxicity. A highly sensitive fluorescence probe was developed using mercaptopropionic acid (MPA) capped CdZnTe quantum dots (QDs) synthesized via an aqueous solution heating method for precise detection of Cr(III) ions. The synthesized MPA-CdZnTe QDs had a size of 2.38 ± 0.13nm and exhibited a zinc-blende structure, with MPA molecules effectively capping the surface through Cd-S bonds. Investigation into the effects of reflux times and solution pH on the absorption and fluorescence spectra of MPA-CdZnTe QDs revealed the occurrence of Ostwald ripening during prolonged reflux processes. The quantum yield (QY) of the synthesized CdZnTe QDs could reach 89%, and the QY was higher under acidic conditions than alkaline. Leveraging the quenching effect of Cr(III) ions on MPA-CdZnTe QDs, a robust method for the quantitative detection of trace amounts of Cr(III) ions was established. Linear quenching behavior was observed within the concentration range of 3.33 × 10- 6 to 5.00 × 10- 4 mol L- 1 for Cr(III) ions, with the fluorescence quenching rate described by a linear regression equation: 1-F/F0 = 0.218 + 829.5268CCr(III). The limit of detection was determined to be 2.63 × 10- 6 mol L- 1. The mechanism of the fluorescence behavior of MPA capped CdZnTe QDs towards Cr(III) ions was photo-induced electron transfer.

Ultrastable NAC-Capped CdZnTe Quantum Dots Encapsulated within Dendritic Mesoporous Silica As an Exceptional Tag for Anti-Interference Fluorescence Aptasensor with Signal Amplification.

In this work, we explored the potential of thiol-capped CdZnTe quantum dots (QDs) as an exceptional signal tag for fluorescence aptasensing applications. Employing a one-pot hydrothermal approach, we modulated the terminal functional groups of CdZnTe QDs using l-cysteine (Lcys), 3-mercaptopropionic acid (MPA), and N-acetyl-l-cysteine (NAC) as ligands. Our comparative analysis revealed that NAC-capped CdZnTe QDs (NAC-CdZnTe QDs) exhibited superior anti-interference capabilities and storage stability across various temperatures, pH levels, and storage durations. Encouraged by these promising results, we further optimized the use of ultrastable NAC-CdZnTe QDs encapsulated in dendritic mesoporous silica nanoparticles (DMSN@QDs) as an exceptional tag for the development of an advanced anti-interference fluorescence aptasensor for aflatoxin B1 (AFB1) detection. The developed aptasensor using DMSN@QDs as signal tags achieved a remarkable signal amplification of approximately 10.2 fold compared to the NAC-CdZnTe QDs coated silica (SiO2@QDs) labeled fluorescence aptasensor. This aptasensor was able to detect AFB1 within a wide range of 1 pg mL-1 to 200 ng mL-1, achieving a limit of detection as low as 0.41 pg mL-1 (S/N = 3). Crucially, the specific binding affinity between the aptamer and the target enabled the aptasensor to be easily customized for various targets by simply replacing the aptamer sequence with the desired one. The exceptional potential of NAC-CdZnTe QDs, particularly when encapsulated in DMSNs, leads to the development of highly sensitive and selective anti-interference fluorescence aptasensors for various targets, thereby, paving the way for advancements in a diverse range of applications.

Self-designed portable dual-mode fluorescence device with custom python-based analysis software for rapid detection via dual-color FRET aptasensor with IoT capabilities

An innovative aptasensor incorporating MoS2-modified bicolor quantum dots and a portable spectrometer, designed for the simultaneous detection of ochratoxin A (OTA) and aflatoxin B1 (AFB1) in corn was developed. Carbon dots and CdZnTe quantum dots were as nano-donors to label OTA and AFB1 aptamers, respectively. These labeled aptamers were subsequently attached to MoS2 receptors, enabling fluorescence resonance energy transfer (FRET). With targets, the labeled aptamers detached from the nano-donors, thereby disrupting the FRET process and resulting in fluorescence recovery. Furthermore, a portable dual-mode fluorescence detection system, complemented with customized python-based analysis software, was developed to facilitate rapid and convenient detection using this dual-color FRET aptasensor. The developed host program is connected to the spectrometer and transmits data to the cloud, enabling the device to have Internet of Things (IoT) characteristics. Connected to the cloud, this IoT-enabled device offers convenient and reliable fungal toxin detection for food safety.

Machine Learning System To Monitor Hg2+ and Sulfide Using a Polychromatic Fluorescence-Colorimetric Paper Sensor.

An optical monitoring device combining a smartphone with a polychromatic ratiometric fluorescence-colorimetric paper sensor was developed to detect Hg2+ and S2- in water and seafood. This monitoring included the detection of food deterioration and was made possible by processing the sensing data with a machine learning algorithm. The polychromatic fluorescence sensor was composed of blue fluorescent carbon quantum dots (CDs) (BU-CDs) and green and red fluorescent CdZnTe quantum dots (QDs) (named GN-QDs and RD-QDs, respectively). The experimental results and density functional theory (DFT) prove that the incorporation of Zn can improve the stability and quantum yield of CdZnTe QDs. According to the dynamic and static quenching mechanisms, GN-QDs and RD-QDs were quenched by Hg2+ and sulfide, respectively, but BU-CDs were not sensitive to them. The system colors change from green to red to blue as the concentration of the two detectors rises, and the limits of detection (LOD) were 0.002 and 1.488 μM, respectively. Meanwhile, the probe was combined with the hydrogel to construct a visual sensing intelligent test strip, which realized the monitoring of food freshness. In addition, a smartphone device assisted by multiple machine learning methods was used to text Hg2+ and sulfide in real samples. It can be concluded that the fabulous stability, sensitivity, and practicality exhibited by this sensing mechanism give it unlimited potential for assessing the contents of toxic and hazardous substances Hg2+ and sulfide.

Synthesis and Photoluminescence Characterization of 3- MPA Capped CdZnTe Quantum Dots

3-MPA capped CdZnTe alloy quantum dots synthesized using Na2TeO3 as the tellurium source under open atmosphere conditions in aqueous medium. The optical and photoluminescence properties of the CdZnTe quantum dots characterized using UV-Visible absorption and Photoluminescence spectrum. An excitonic peak at 527 nm observed in the absorption spectrum. Tauc relation and Urbach relation were employed to find the bandgap energy and urbach energy of the CdZnTe quantum dot. The quantum dot particle size was estimated using the bandgap energy from Tauc plot employing tight binding approximation, which was 4.75 nm. A high intense emission peak at 567 nm obtained in the photoluminescence spectrum. The emission peaks correspond to yellow fluorescence. The CIE chromaticity diagram gives color coordinate at (0.41,0.56) with a color purity of 92%. The high intense yellow fluorescent CdZnTe quantum can placed as potential candidates for fluorescent probes, biolabeling and cell imaging applications.

Optical and dielectric investigations on Ag: CdZnTe hybrid polyvinyl alcohol freestanding films

Hybrid freestanding films of polyvinyl alcohol incorporated with silver and CdZnTe quantum dots were synthesized. The effect of varying silver concentration on optical and dielectric properties were studied. Structural and morphological analysis of hybrid films were done using X-ray diffraction and transmission electron microscopy. Optical parameters like absorption coefficient, extinction coefficient, refractive index, optical bandgap, urbach energy and optical conductivity were studied for the polymer nanocomposite for 0 to 0.3 wt percentage of silver content. With increasing silver content, a decrease in bandgap energy and an increase in urbach energy was observed. Dielectric constants, loss tangent and AC conductivity values of hybrid films were found to improve, with silver addition and highest values were obtained for 0.2 wt percentage. Complex impedance plots provided semicircles and Cole-Cole parameters were calculated. The nature of impedance plot revels single relaxation process and this was effectively modelled through an equivalent RC parallel circuit.

Controlling the ligands of CdZnTe quantum dots to design a super simple ratiometric fluorescence nanosensor for silver ion detection.

A super simple ratiometric fluorescence nanosensor has been fabricated by controlling the ligands of CdZnTe quantum dots (QDs), allowing the sensitive and visual detection of silver ions (Ag+). The green-emitting L-cysteine-protected CdZnTe QDs (Lcys-CdZnTe QDs) had a specific response to Ag+ and were used as the reporting probe, while the red-emitting N-acetyl-L-cysteine-protected CdZnTe QDs (NAC-CdZnTe QDs) showed no obvious response to all tested metal ions and were selected as the reference probe. Simply mixing them without any encapsulated synthesis ultimately produced a time-saving, low-cost detection method, allowing the sensitive and visual detection of Ag+ in samples. The proposed nanosensor exhibited a linear range of 0.5-4.0 μM along with a detection limit of 0.17 μM, and has been successfully applied in real tap water and lake water samples. This nanosensor also showed obvious color changes in the detection process and has potential in visual semi-quantitative detection. Our approach may provide a general and feasible strategy for designing ratiometric fluorescence nanosensors, which will attract a wide range of interest in sensing-related fields.

Controlling over the terminal functionalities of thiol-capped CdZnTe QDs to develop fluorescence nanosensor for selective discrimination and determination of Fe(II) ions

Development of highly sensitive and selective methods for metal ions detection has been considered as one of the basic issues for environmental protection and human health. On basis of our success in one-pot hydrothermal route synthesized thiol-capped CdZnTe quantum dots (QDs) with different terminal functionalities, we demonstrated that N-acetyl-l-cysteine capped CdZnTe QDs (NAC-CdZnTe QDs) were quite stable to all of the tested metal ions, l-cysteine capped CdZnTe QDs (Lcys-CdZnTe QDs) exhibited quenched fluorescence behavior towards both Fe2+ and Ag+ ions while 3-mercaptopropionic acid capped CdZnTe QDs (MPA-CdZnTe QDs) featured to highly selective fluorescence response towards Fe2+ ions. The mechanism of the fluorescence behavior of thiol-capped CdZnTe QDs towards different metal ions has been discussed in depth. Such designed nanosensor based on MPA-CdZnTe QDs showed decreased fluorescence upon the introduction of increasing concentrations of Fe2+. There was a good linear relationship between the fluorescence intensity of MPA-CdZnTe QDs over a wide concentration range of 0.64−48 μM with a low detection limit of 0.2 μM on basis of S/N=3. The developed nanosensor could distinctly discriminate between two oxidation states of Fe (Fe2+ and Fe3+), and has succeeded in dissolved Fe fertilizer (FeSO4) for potted flower and spiked water samples analysis. This study not only offers a general route for the surface-engineering of ternary alloyed QDs to have desired terminal functionalities but also highlights the significance of surface chemistry in controlling the fluorescence behavior of QDs towards metal ions detection.

Bi-color FRET from two nano-donors to a single nano-acceptor: A universal aptasensing platform for simultaneous determination of dual targets

Emerging nano-donor and nano-receptor FRET pairs are more advantageous to broad biosensing applications. However, those reported FRET system generally containing a single pair cannot afford multiplexed analysis. Herein, bi-color FRET from two nano-donors to a single nano-acceptor has been adopted to fabricate a simple-to-use aptasensor for simultaneous determination of dual targets in a single run. Aflatoxin B1 (AFB1) and ochratoxin A (OTA) were selected as the analytes because they have synergistic effect to induce enhanced toxicity. Specially, carbon dots (CDs) and CdZnTe quantum dots (QDs), with unambiguous separation of emission peaks, were used as nano-donors to label the aptamers specific for AFB1 and OTA, respectively. These single-stranded aptamers with labels could be stably adsorbed on a single nano-acceptor MoS2 nanosheets surface due to van der Waals force, leading to the occurrence of FRET. When the aptasensor incubated with AFB1 and OTA, the specific binding between aptamers and targets resulted in partial release of the nano-donor labeled aptamers which disturb the FRET process and ultimately led to the fluorescence recovery to some extent. This aptasensor exhibited a wide detection range of 0.01–10 ng mL−1 for AFB1 and 0.02–5 ng mL−1 for OTA with low detection limits (3.3 pg mL−1 for AFB1 and 7.1 pg mL−1 for OTA). This aptasensor provides a new avenue for simultaneous determination of dual mycotoxins due to its advantages of simple operation, good selectivity and high sensitivity. By simply changing the specific aptamer, our strategy will certainly provide a universalaptasensing platform in advancing multiplexed analysis.

A fluorometric turn-on aptasensor for mucin 1 based on signal amplification via a hybridization chain reaction and the interaction between a luminescent ruthenium(II) complex and CdZnTeS quantum dots

A fluorometric method is described for the determination of the tumor biomarker mucin 1 (MUC1). It is based on signal amplification of the hybridization chain reaction (HCR), and the interaction between a luminescent ruthenium(II) complex and CdZnTeS quantum dots (QDs). If MUC1 bind to the biotin-labeled aptamer, it will initiate HCR with hairpins H1 and H2 to form a long-range dsDNA. The long nucleic acid chains are then linked on the surface of streptavidin-modified magnetic microparticles (MMPs) through streptavidin-biotin interaction. The luminescent ruthenium(II) complex is then embedded in the long dsDNA linked to the MMPs. Hence, there is little Ru complex in the supernatant after magnetic separation, and the fluorescence of the CdZnTeS QDs (best measured at excitation/emission wavelengths of 350/530nm) is only slightly quenched. In the absence of target, the fluorescence of the CdZnTeS QDs is strongly quenched. Fluorescence increases linearly in the 0.2-100ng·mL-1 MUC1 concentration range, and the LOD is 0.13ng·mL-1 (at S/N= 3). The method was applied to the determination of MUC1 in spiked human serum samples. Graphical abstract A fluorometric turn-on aptasensor for mucin 1 is described that is based on theinteraction between aRu(II) complex and quantum dots (QDs). The detection system includes biotin-labeled aptamer-H0, hairpins H1 and H2, streptavidin-modified magnetic microparticles (MMPs), Ru(bpy)2(dppx)2+ and CdZnTeS QDs.

Dual-protein visual detection using ratiometric fluorescent probe based on Rox-DNA functionalized CdZnTeS QDs

Herein, we developed a simple and sensitive method for the detection of protamine and trypsin by using a ratiometric fluorescent probe based on Rox-DNA functionalized CdZnTeS quantum dots (QDs). The Rox-DNA functionalized CdZnTeS QDs were prepared via one-pot method, which was simple, low-cost, and modification-free. Protamine can cause the aggregation of ratiometric fluorescent probe through electrostatic interaction and quench the fluorescence of CdZnTeS QDs. Then, the protamine could be hydrolyzed to small peptides by trypsin and the fluorescence of QDs was recovered. However, the fluorescence of Rox kept unchanged. The fluorescence intensity ratio was proportional to the concentration of protamine or trypsin. A good linear relationship (25–300 ng/mL for protamine and 2.5–50 ng/mL for trypsin) with low limit of detection (4.73 ng/mL for protamine and 0.87 ng/mL for trypsin) was obtained. Meanwhile, we observed different colors by the naked eye after the addition of different concentrations of protamine and trypsin, and the minimum detectable concentration was as low as 4 μg/mL for protamine and 40 ng/mL for trypsin, respectively. In addition, the ratiometric fluorescent probe exhibited good analytical performance in complex biological matrix. Therefore, the ratiometric fluorescent probe can be proposed as a simple and effective tool for the detection and visualization of dual proteins.

Target-driven switch-on fluorescence aptasensor for trace aflatoxin B1 determination based on highly fluorescent ternary CdZnTe quantum dots

Development of sensitive methods for trace aflatoxin B1 (AFB1) determination is of great significance due to its high toxicity and carcinogenicity. Herein, 3-mercaptopropionic acid (MPA)-capped ternary CdZnTe quantum dots (QDs) have been prepared via a simple hydrothermal route. We found that they exhibited enhanced intensity when benchmarked against their binary counterpart CdTe QDs. On this basis, a target-driven switch-on fluorescence aptasensor for trace AFB1 determination has been developed by employing the fluorescence resonance energy transfer (FRET) between the CdZnTe QDs and Au nanoparticles (AuNPs) pair. In the detection diagram, amino group-functionalized aptamers against AFB1 were firstly labelled with the CdZnTe QDs donors coated on silica nanospheres while the AuNPs acceptors were bioconjugated with the thiol group-modified complementary DNA (cDNA) of aptamer. By taking advantage of the DNA hybridization of aptamer and cDNA, the CdZnTe QDs (energy donor) and AuNPs (energy acceptor) were brought into close proximity, thereby leading to the occurrence of FRET during the aptasensor fabrication. When the aptasensor was incubated with AFB1, the specific binding between aptamer and target resulted in the detachment of AuNPs acceptors. This behavior would disturb the FRET process and led to the subsequent fluorescence recovery of CdZnTe QDs. Such designed aptasensor showed an increased fluorescence recovery upon the increasing concentration of AFB1 over a broad range of 50 pg mL−1 – 100 ng mL−1 and succeeded in spiked peanut samples. The proposed aptasensor is separation-free and easy-to-use, which might open up new possibilities in aptasensor fabrication by employing the novel CdZnTe QDs-AuNPs pair.

CdZnTeS quantum dots based electrochemiluminescent image immunoanalysis

In this work, quaternary CdZnTeS quantum dots (QDs) with a particularly strong electrochemiluminescence (ECL) were synthesized as ECL signal labels. The strong ECL signals can be obtained at both cathode and anode with the ECL efficiencies of 19.78% and 1.62%, respectively. The sandwich-structured ECL immunosensors for the detection of alpha-fetoprotein (AFP) and cancer antigen 125 (CA125) were accomplished with direct ECL image analysis. Under optimal conditions, the QDs-based ECL image immunoanalysis possessed good linearity from 0.5 ng/mL to 20 ng/mL for AFP and from 20 U/mL to 500 U/mL for CA125 with the detection limit of 0.1 ng/mL and 6 U/mL, respectively (S/N = 3), and the lower detection limit obtained by photomultiplier tube were 0.1 fg/mL for AFP and 0.03 mU/mL for CA125 with the wide dynamic range from 0.5 fg/mL to 20 ng/mL and from 0.1 mU/mL to 500 U/mL, respectively (S/N = 3). Furthermore, the ECL immunoanalysis was evaluated with commercial enzyme-linked immunosorbent assay in human serum samples. The good results indicated that CdZnTeS QDs-based ECL biosensor has great potential for fast biomedical screening and multi-assays in clinical diagnosis.

One-pot synthesis of the stable CdZnTeS quantum dots for the rapid and sensitive detection of copper-activated enzyme

Galactose oxidase is a copper-activated enzyme and have a vital role in metabolism of galactose. Much of the work is focused on determining the amount of galactose in the blood rather than measuring the amount of galactose oxidase to urge the galactosemia patients to restrict milk intake. Here, a simple and effective method was developed for Cu2+ and copper-activated enzyme detection based on homogenous alloyed CdZnTeS quantum dots (QDs). Meso− 2,3-dimercaptosuccinic acid (DMSA) was used as the reducing agent for preparing QDs and the highest quantum yield of CdZnTeS QDs was 69.4%. In addition, the as-prepared CdZnTeS QDs show superior fluorescence properties, such as good photo-/chemical stability. The DMSA was the surface ligand of the QDs, containing abundant -SH and -COOH, thus the surface ligands have a high affinity with Cu2+. Therefore, this developed probe can be applied for Cu2+ and galactose oxidase detection and shows a good sensitivity in the buffer. Then, this probe was successfully used for Cu2+ and galactose oxidase detection in real samples with the satisfactory results. The proposed fluorescence quenching strategy gives a new and simple insight for enzyme assay without the enzyme-catalyzed reaction.

One-Step Synthesis of Rox-DNA Functionalized CdZnTeS Quantum Dots for the Visual Detection of Hydrogen Peroxide and Blood Glucose.

As the blood glucose concentration is an important clinical parameter of diabetes, the rapid and effective detection of blood glucose is very significant for monitoring and managing diabetes. Here, a facile method to prepare Rox-DNA functionalized CdZnTeS quantum dots (QDs) was developed. The Rox-DNA functionalized CdZnTeS QDs were prepared by a one-pot hydrothermal method through phosphorothioate DNA bound to QDs, which were employed as a ratiometric fluorescent probe for the rapid and sensitive detection of H2O2 and glucose. Compared with the traditional multistep construction of ratiometric fluorescent probes, this presented approach is simpler and more effective without chemical modification and complicated separation. The CdZnTeS QDs with green fluorescence is specifically sensitive to H2O2, while the red fluorescence of Rox is invariable. H2O2 is the product from the oxidation of glucose catalyzed by glucose oxidase (GOx). Therefore, a facile method to detect H2O2 and glucose with a detection limit of 0.075 μM for H2O2 and 0.042 μM for glucose was developed. In addition, this proposed probe has been employed for the detection of glucose in human serum with a satisfactory result. Moreover, this probe has been used for visual detection, and the health and diabetics can be distinguished by the naked eye. Meanwhile, this nanoprobe is also generalizable and can be extended to the detection of many other H2O2-mediated analytes.

High luminescent aqueous CdZnTe QDs incorporated in CaCO3 for excellent color-rendering WLEDs

A facile synthesis of aqueous CdZnTe quantum dots (QDs) incorporated in CaCO3 matrix is demonstrated, providing a new type of solid-state light conversion material. Highly luminescent CdZnTe QDs were firstly synthesized using CdCl2, ZnCl2 and Te as precursors and 3-Mercaptopropionic acid (MPA) as ligand. Then CdZnTe QDs were incorporated into CaCO3 matrix through a co-precipitation method. Due to the protection of the tight matrix, the resulting CdZnTe QDs/CaCO3 composites exhibit good photostability and processability as well as high photoluminescence properties. A white light-emitting diode (WLED) applying the composites as a red color conversion layer was also fabricated, which showed excellent performance including a Commission Internationale de I'eclairage (CIE) color coordinate of (0.3662, 0.3396), a high color rendering index (Ra) of 92.7 and a low correlated color temperature (Tc) of 4146 K under 20 mA forward-bias current, suggesting the promising application of the composites in solid-state lighting systems.

Structural and optical properties of CdZnTe quantum dots capped with a bifunctional Molecule

CdTe and ternary CdZnTe quantum dots capped with 3-mercaptopropionic acid in aqueous medium with different percentages of Zn have been prepared using K2TeO3 as a source of tellurium. The structure and morphology of these quantum dots were characterized by XRD, TEM, EDX, FTIR and Raman spectroscopy. The results revealed that the ternary CdZnTe quantum dots (QDs) have nearly spherical shape with hexagonal structure. Doping with Zn leads to a pronounced change in relative intensity of the X-ray diffraction peaks. The optical properties were investigated by using UV–Vis absorption and photoluminescence measurements. The UV–Vis showed a gradual increase in the optical band gap of ternary alloy compound of CdZnTe QDs plus a continuous shift of photoluminescence emission with increasing of Zn content. The color distribution analysis showed a gradual change in color with Zn percentage for red, green and blue components. The nanoparticle sizes were determined from optical absorption, XRD, Raman and HRTEM measurements indicating that the prepared binary CdTe and ternary CdZnTe capped with MPA are in a strong confinement regime as an indicative of quantum dots structure.

Synthesis of CdZnTe Quantum Dots in the Aqueous Phase by Microwave Irradiation

Synthesis of CdZnTe Quantum Dots in the Aqueous Phase by Microwave Irradiation

Size-confined fixed-composition and composition-dependent engineered band gap alloying induces different internal structures in L-cysteine-capped alloyed quaternary CdZnTeS quantum dots.

The development of alloyed quantum dot (QD) nanocrystals with attractive optical properties for a wide array of chemical and biological applications is a growing research field. In this work, size-tunable engineered band gap composition-dependent alloying and fixed-composition alloying were employed to fabricate new L-cysteine-capped alloyed quaternary CdZnTeS QDs exhibiting different internal structures. Lattice parameters simulated based on powder X-ray diffraction (PXRD) revealed the internal structure of the composition-dependent alloyed CdxZnyTeS QDs to have a gradient nature, whereas the fixed-composition alloyed QDs exhibited a homogenous internal structure. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis confirmed the size-confined nature and monodispersity of the alloyed nanocrystals. The zeta potential values were within the accepted range of colloidal stability. Circular dichroism (CD) analysis showed that the surface-capped L-cysteine ligand induced electronic and conformational chiroptical changes in the alloyed nanocrystals. The photoluminescence (PL) quantum yield (QY) values of the gradient alloyed QDs were 27–61%, whereas for the homogenous alloyed QDs, the PL QY values were spectacularly high (72–93%). Our work demonstrates that engineered fixed alloying produces homogenous QD nanocrystals with higher PL QY than composition-dependent alloying.

Aqueous synthesis of high-fluorescence CdZnTe alloyed quantum dots

High luminescent CdZnTe quantum dots (QDs) were synthesized by a one-step aqueous method using 3-mercapto propionic acid (MPA) as a stabilizer. The as-prepared samples are in good homogeneity and dispersity with an average particle size of 5nm. Accordingly, the size and composition-dependent fluorescent emission wavelength of the resultant CdZnTe alloyed QDs can be continuously tuned from 490 to 660nm. Compared with the difficult acquisition of CdZnTe QDs with a high Zn/Cd molar ratio in alkaline condition, CdZnTe QDs with a Zn/Cd molar ratio from 1 to 7 has been obtained in weak acid condition by adjusting the pH value of precursor solution. The maximum quantum yield has reached nearly 80% without any post-treatment. And it also showed excellent stability against time.