Water Dispersible CdSe/ZnS Quantum Dots
Inquiry
Product Description
Alfa Chemistry offers water-soluble CdS/ZnS core-shell quantum dots that provide narrow-band fluorescence emission in the 480 nm to 660 nm wavelength range and are coated with a hydrophilic surfactant for dispersion in water. Alfa Chemistry can also customize CdS/ZnS core-shell quantum dots in water-soluble form with surfactant end groups that These can be carboxylic acids (-COOH), primary amines (-NH2) or diols (-CHOH-CH2OH). These coatings allow QDs to be covalently bonded to a variety of molecular probes and surfaces for many fluorescent labeling applications.
Applications
Optical Devices
The polymer-CdSe/ZnS quantum dot photoluminescence composite films were prepared by Zhou et al. using a phase transfer method to prepare water-soluble CdSe/ZnS fluorescent quantum dots modified by amphoteric zwitterionic (PMAH). The fluorescence intensity of the composite films increased with the increase of quantum dot concentration in the films under the same number of coating times; in addition, the fluorescence intensity of the composite films increased with the increase of coating times, indicating a more uniform film growth. The prepared films emitted a bright red light under the UV light. The tolerance of the composite films to UV light was tested under UV light, and the results showed that the prepared composite fluorescent films had a long life under light, with only 5% loss of fluorescence intensity after 800 h of light exposure. The polymer-CdSe/ZnS quantum dot composite films prepared by this method will have good application prospects in the field of photoluminescent devices.
Fig.1 UV-Vis absorption spectra (a) and photoluminescence spectra (b) of hydrophobic (dash line) and PMAH-coated aqueous (solid line) CdSe/ZnS QDs. (Zhou et al, 2010)
Fluorescence Detection
Vasudevan et al. reported the fluorescence response of water-dispersible CdSe/ZnS core-shell quantum dots capped with 2-mercaptopropionic acid (2MPA) to different concentrations of heavy metal cations (i.e., Hg, Pb, and Cd). A concentration-dependent decrease in the fluorescence emission of the quantum dots was observed upon exposure to different concentrations of various metal cations, which were exponentially decaying in nature. The maximum quenching was reached in the presence of mercury. The resulting quantum dots were subsequently characterized by UV-Vis spectroscopy, photoluminescence spectroscopy, Raman spectroscopy and X-ray diffraction. The quantitative detection of mercury, lead and cadmium cations by these capped quantum dots makes them exciting candidates for heavy metal sensing applications.
Our products are constantly updated. If the product you need is not in our catalog, please feel free to contact us , we provide relevant custom services.
References
- Zhou C. H., Wang X., et al. Preparation and Characterization of Polymer-CdSe/ZnS QDs Composite Thin Film. Journal of Inorganic Materials, 2010,25(07):700-704.
- Vasudevan, D. , et al. Fluorescent heavy metal cation sensing with water dispersible 2MPA capped CdSe/ZnS quantum dots. Journal of Luminescence, 2015, 166:88-92.
* It should be noted that our service is only used for research, not for clinical use.
