Comparative Studies on the Aqueous Synthesis and Biocompatibility of L-Cysteine and Mercaptopropionic Acid Capped CdSe/CdS/ZnS Core/Shell/Shell Quantum Dots

Quantum dots have now become the most important candidates and widely exploited as promising architectures for use as diagnostic and imaging agents in biomedicine and as semiconductors in the electronics industry. This article emphasizes on the aqueous synthesis of water soluble CdSe/CdS/ZnS core/shell/shell quantum dots with L-cysteine and mercaptopropionic acid as capping agent and their observed properties have been compared. The biocompatibility of the assynthesized quantum dots have also been analyzed through the cytotoxicity study using MTT assay. The structural, morphological and optical properties of these quantum dots have been examined through X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), UV-Visible absorption spectroscopy (UV-Vis) and Photoluminescence spectroscopy (PL). The capping of L-cysteine and mercaptopropionic acid on the quantum dots has been confirmed from Fourier transform infrared spectroscopy (FTIR). XRD results demonstrated the formation of hexagonal wurtzite structure for L-cysteine and cubic zinc blende structure for mercaptopropionic acid capped CdSe/CdS/ZnS quantum dots. From the optical measurements, it is observed that there is a considerable increase in the photoluminescence intensity of L-cysteine capped quantum dots than MPA. The HRTEM images revealed the narrow size distribution and in addition, L-cysteine capped quantum dots were found to be more biocompatible than mercaptopropionic acid capped quantum dots which would provide new opportunities for applications in bioimaging and biolabelling.

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AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD

NANO ◽

10.1142/s1793292012500117 ◽

2012 ◽

Vol 07 (02) ◽

pp. 1250011 ◽

Cited By ~ 2

Author(s):

JUNWEI LI ◽

YANG JIANG ◽

YUGANG ZHANG ◽

DI WU ◽

ANQI LUO ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Quantum Dots ◽

Quantum Yield ◽

Electrochemical Method ◽

Large Scale ◽

Ostwald Ripening ◽

Visible Absorption ◽

Aqueous Synthesis ◽

Transmission Electron

A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.

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Layer-by-layer aqueous synthesis, characterization and fluorescence properties of type-II CdTe/CdS core/shell quantum dots with near-infrared emission

RSC Advances ◽

10.1039/c3ra43120g ◽

2013 ◽

Vol 3 (43) ◽

pp. 20959-20969 ◽

Cited By ~ 20

Author(s):

Rijun Gui ◽

Xueqin An

Keyword(s):

Quantum Dots ◽

Near Infrared ◽

Infrared Emission ◽

Water Soluble ◽

Core Shell ◽

Layer By Layer ◽

Type Ii ◽

Cds Quantum Dots ◽

Aqueous Synthesis ◽

Near Infrared Emission

A layer-by-layer epitaxial method was developed to synthesize water-soluble, near-infrared (NIR)-emitting type-II core–shell CdTe/CdS quantum dots (QDs) via employing glutathione-capped CdTe QDs as core templates, CdCl2 and thiourea as shell precursors.

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Novel aqueous synthesis methods for ZnTe/ZnSe and Mn2+-doped ZnTe/ZnSe Type-II core/shell quantum dots

RSC Advances ◽

10.1039/c4ra12727g ◽

2015 ◽

Vol 5 (9) ◽

pp. 6271-6278 ◽

Cited By ~ 9

Author(s):

Yu Song ◽

Yang Li ◽

Xinyan Wang ◽

Xingguang Su ◽

Qiang Ma

Keyword(s):

Quantum Dots ◽

Core Shell ◽

Synthesis Methods ◽

Type Ii ◽

Aqueous Synthesis ◽

Mercaptopropionic Acid ◽

Novel Approaches

In this paper, novel approaches for the synthesis of Type-II core/shell quantum dots (ZnTe/ZnSe QDs) and Mn2+-doped Type-II core/shell quantum dots (Mn : ZnTe/ZnSe QDs) with mercaptopropionic acid (MPA) as stabilizer were proposed.

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