Synthesis and spectroscopic characterization of water-soluble Mn-doped ZnOxS1−x quantum dots

2011 ◽  
Vol 83 (1) ◽  
pp. 348-352 ◽  
Author(s):  
Fangfang Xue ◽  
Jiangong Liang ◽  
Heyou Han
Keyword(s):  
Quantum Dots ◽  
Spectroscopic Characterization ◽  
Water Soluble ◽  
Mn Doped

Synthesis and characterization of water-soluble ZnO quantum dots prepared through PEG-siloxane coating

2008 ◽  
Vol 32 (8) ◽  
pp. 1388 ◽  
Author(s):  
Ralph-Olivier Moussodia ◽  
Lavinia Balan ◽  
Raphaël Schneider
Keyword(s):  
Quantum Dots ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Zno Quantum Dots

scholarly journals Spectroscopic Characterization of Natural Melanin from a Streptomyces cyaneofuscatus Strain and Comparison with Melanin Enzymatically Synthesized by Tyrosinase and Laccase

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1916 ◽  
Author(s):  
Maher Al Khatib ◽  
Mohamed Harir ◽  
Jessica Costa ◽  
Maria Baratto ◽  
Irene Schiavo ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Water Soluble ◽  
Stable Free Radical ◽  
Paramagnetic Resonance ◽  
Solid Media ◽  
Algerian Sahara ◽  
X Band ◽  
Ft Ir ◽  
Synthetic Pigments

An actinobacteria strain was isolated from Algerian Sahara soil and assigned to Streptomyces cyaneofuscatus Pridham et al. 1958 species. This strain was selected for its ability to produce melanin exopigments in liquid and solid media. Melanin synthesis was associated with tyrosinase activity and the enzyme from this strain was isolated and biochemically characterized. Synthetic melanin was then enzymatically produced using the S. cyaneofuscatus Pridham et al. 1958 tyrosinase. As this enzyme showed a higher diphenolase activity, a synthetic melanin from the enzymic oxidation of 3,4-dihydroxyphenylalanine (dopa) was obtained by the use of a Trametes versicolor (L.) Lloyd laccase for comparison. The natural and synthetic pigments were physico-chemically characterized by the use of ultraviolet (UV)-Visible, and Fourier transform infrared (FT-IR) and multifrequency electron paramagnetic resonance (EPR) spectroscopies. All the melanin samples displayed a stable free radical when analyzed by X-band EPR spectroscopy. Once the samples were recorded at Q-band EPR, a copolymer derived from a mixture of different constituents was evident in the natural melanin. All radical species were analyzed and discussed. The use of water-soluble melanin naturally produced by S. cyaneofuscatus Pridham et al. 1958 represents a new biotechnological alternative to commercial insoluble pigments.

Preparation and Characterization of Water-Soluble CdSe/CdS Core/Shell Quantum Dots

2012 ◽  
Vol 549 ◽  
pp. 212-215
Author(s):  
Ming Li Li ◽  
Qiong Yu ◽  
Ying Xu ◽  
Chun Jiang Zhou ◽  
Qing Guo Lu
Keyword(s):  
Quantum Dots ◽  
Energy Band ◽  
Xrd Analysis ◽  
High Energy ◽  
Water Soluble ◽  
Excitation Wavelength ◽  
Core Shell ◽  
Electron Hole ◽  
Energy Peak

Cadmium Selenide/Cadmium Sulfide (CdSe/CdS) core/shell quantum dots (QDs) in aqueous solution were prepared by solve-separate method using CdSe as core and mercapto-acetate acid as stabilizer and surfactants. The results of experiments indicate that the size of the CdSe/CdS QDs was about 5nm estimated by FE-TEM, which is accordant with that calculated from the XRD data by the Scherer equation after emendation. The QDs belong to the cubic structure (zinc blende) by XRD analysis. The intensity of luminescence of the quantum dots was greatly improved after the surface was coated with CdS shell. With increasing the time of refluence, the intensity of photoluminescence was promoted correspondingly. The excitation wavelength was 350nm, two emission peaks were clearly observed, the first high-energy peak was at 600nm and the second one located in 700nm. The first high-energy band was attributed to electron–hole recombination after relaxation and the second energy band was to deep traps in quantum-confined systems.

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