Photoluminescent Characteristics of ZnS Quantum Dots Synthesized in Non-Aqueous-Phase

2013 ◽  
Vol 750-752 ◽  
pp. 991-994
Author(s):  
Jing Liu ◽  
Ming Ying ◽  
Yu Ling Tan ◽  
Bo Xi
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Reaction Medium ◽  
Emission Spectra ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Zinc Blend ◽  
Red Emission ◽  
X Ray

ZnS quantum dots (ZnS QDs) synthesized in aqueous solution is easy to gather a mass, which always results in low quantum yield. So, in this study benzene was used as reaction medium in which ZnS QDs with different hues were synthesized, and the hues of ZnS QDs were depend on the molar ratio of Zn (CH3COO)2 and Na2S·9H2O. The results show the emission spectra of ZnS QDs shifts with the change of the precursor molar ratio but the absorption peak at 310nm is not. The emission peaks centered at 430nm and 580nm at higher molar ratio [Zn2+]/[S2-] with blue-violet emitting phosphors; but, ZnS QDs synthesized at higher molar ratio [S2-]/[Zn2+] have orange-red emission at 580nm only. The X-ray diffraction analysis shows the crystallinity of ZnS QDs is better at [Zn2+]/[S2-]=1:10, which are typical zinc blend with nanorod structure.

Synthesis and Characterization of CdTe Quantum Dots Capped by N-Acetyl-L-Cysteine

2013 ◽  
Vol 275-277 ◽  
pp. 1956-1959
Author(s):  
Xiu Lin Liao ◽  
Na Yang ◽  
Lin Xiang Xie ◽  
Xiao Cui Yang ◽  
Xiu Pei Yang
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Emission Spectra ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cdte Qds ◽  
Transmission Electron ◽  
Cadmium Telluride Quantum Dots

The highly luminescent cadmium telluride quantum dots (CdTe QDs) have been synthesized by using N-acetyl-L-cysteine (NAC) as stabilizer in aqueous solution. Experiments indicate that the QDs nanocrystals could grow larger as the extension of reaction time, causing the red shift of emission spectra. The typical product was analyzed by fluorescence spectroscopy, high-resolution transmission electron microscope (HRTEM), x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The morphological and structural characterization confirmed the formation of monodisperse CdTe QDs with several nanometers in size.

Synthesis, Characterization and Photocatalytic Activity of Nb-Doped TiO2 Nanoparticles

2012 ◽  
Vol 455-456 ◽  
pp. 110-114 ◽  
Author(s):  
Xuan Dong Li ◽  
Xi Jiang Han ◽  
Wen Ying Wang ◽  
Xiao Hong Liu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Doped Tio2 ◽  
X Ray ◽  
Vis Spectroscopy

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.

Novel Cyclometalated Iridium(III) Xanthate Complexes and Their Phosphorescence Behavior in the Presence of Metal Ions

2012 ◽  
Vol 67 (9) ◽  
pp. 865-871
Author(s):  
Bihai Tong ◽  
Yaqing Xu ◽  
Jiayan Qiang ◽  
Man Zhang ◽  
Qunbo Mei ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Metal Ions ◽  
Single Crystal ◽  
Photophysical Properties ◽  
Metal Cations ◽  
X Ray Diffraction ◽  
Red Emission ◽  
X Ray ◽  
Emission Lifetime ◽  
Phosphorescence Quantum Yield

Two cyclometalated iridium(III) complexes, Ir(dpppz)(ppz)(ipx) and Ir(ppz)2(ipx) (dpppzH=1- (2,6-dimethylphenoxy)-4-phenylphthalazine, ppzH=4-phenylphthalazinone, ipx=isopropyl xanthate), have been synthesized and characterized by single-crystal X-ray diffraction. The photophysical properties of the two complexes were also investigated. Ir(dpppz)(ppz)(ipx) shows orange-red emission at around 606 nm with a phosphorescence quantum yield of ca. 0.0032 and an emission lifetime of 188 ns, while Ir(ppz)2(ipx) shows orange-red emission at around 599 nm with a phosphorescence quantum yield of ca. 0.00318 and an emission lifetime of 259 ns. The phosphorescence behavior of Ir(ppz)2(ipx) towards different metal cations has also be studied. Its strong phosphorescence is quenched by Hg2+, Cu2+ and Ag+ cations. The interaction ratio with Hg2+ is 1:1

Photoluminescence properties of Li2+xNb3xTi1−4xO3:Eu3+

2019 ◽  
Vol 12 (04) ◽  
pp. 1950057 ◽  
Author(s):  
Chao-Chao Guo ◽  
Qun Zeng ◽  
Chun-Feng Yao ◽  
Yan-Zhao Feng ◽  
Xi Chen ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Red Emission ◽  
Reaction Method ◽  
X Ray ◽  
Red Phosphors ◽  
Chromaticity Coordinate

Red phosphors with compositions of Li[Formula: see text]Nb[Formula: see text]Ti[Formula: see text]O3:3[Formula: see text]wt.% Eu[Formula: see text] [Formula: see text] were synthesized by solid-state reaction method. The samples were investigated by using X-ray diffraction (XRD) and photoluminescence spectroscopy, respectively. XRD results showed that all samples were main phase of Li2TiO3. Emission spectra of Li[Formula: see text]Nb[Formula: see text]Ti[Formula: see text]O3:3[Formula: see text]wt.% Eu[Formula: see text] powders showed strong red emission at 612[Formula: see text]nm (5D0–7F[Formula: see text] with 396[Formula: see text]nm excitation. In addition, the excitation and emission intensity increased up to [Formula: see text], and then decreased with further increasing of the x values. And the chromaticity coordinate (CIE) of the component with [Formula: see text] was superior to other components.

scholarly journals Removal of Lead from Aqueous Solution by Adsorption using Magnesium Aluminium Hydrogenphosphate Layered Double Hydroxides

2014 ◽  
Vol 8 (1) ◽  
Author(s):  
Zaini Hamzah ◽  
Mohd Najif Ab Rahman ◽  
Yamin Yasin ◽  
Siti Mariam Sumari ◽  
Ahmad Saat
Keyword(s):  
Aqueous Solution ◽  
Layered Double Hydroxide ◽  
Molar Ratio ◽  
Maximum Adsorption Capacity ◽  
Lead Removal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
Double Hydroxide ◽  
Double Hydroxides

Layered double hydroxide with molar ratio of 4 (MAN 4) was synthesized by co-precipitation and followed by hydrothermal method. The compound was then later going through ion exchange with K2HPO4 for 48 hours to produce MgAlHPO4 (MAHP 4). The solid produced were characterized using X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). Adsorption of lead solution by MAHP 4 was carried out using batch experiment by mixing the lead solution and the solid of layered double hydroxide. The effects of various parameters such as contact time, pH, adsorbent dosage and initial concentration were investigated. The optimum pH for lead removal was found to be at pH of 5 and the optimum time of lead removal was found at 2 hours. The isotherm data was analysed using Langmuir and the correlation coefficient of 0.998 was obtained. The maximum adsorption capacity, Qo (mg/g) of 500 mg/g was also recorded from the Langmuir isotherm. The remaining lead solution was determined by using EDXRF (Energy Dispersive X-Ray Fluorescence spectrometry) model MiniPal 4 (PAN analytical). The results in this study indicate that MAHP 4 was an interesting adsorbent for removing lead from aqueous solution.

Preparation and Photocatalytic Activity of TiO2/Fe2O3 Nanocomposite

2011 ◽  
Vol 130-134 ◽  
pp. 2396-2399
Author(s):  
Su Juan Hu ◽  
Xuan Hui Zhang ◽  
Ying He ◽  
Xian Chao Hu ◽  
Lei Cheng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Electron Microscope ◽  
Synergistic Effect ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particle Coating ◽  
Transmission Electron ◽  
Phase Pure

TiO2/Fe2O3 nanocomposite was fabricated by a hydrolysis-precipitation approach, with TiCl4 as precursor and Fe2O3 as support. The crystal phase, diameter and morphology of the sample particle were characterized by X-ray diffraction, transmission electron microscope. The results show that the samples are composed of haematite and rutile. The morphology and diameter of rutile particle, coating effect and weight percentages of haematite and rutile are related to the preparing temperature and molar ratio of Fe/Ti. The photocatalytic activity of the prepared photocatalyst was estimated in an aqueous solution at ambient temperature of 303K. The results imply that the photocatalytic activity of the sample is higher than that of phase pure rutile, related to Fe/Ti molar ratio and its preparing temperature. These results can be attribute to the microsturcture of the sample. A synergistic effect exists between titania and haematite in the nanocomposite.

Combustion Synthesis of Nanocrystalline Y2O2S: Eu 3+ , Mg 2+ , Ti 4+ Red Long-Lasting Phosphors Using Mixture Fuel of Thiourea and Citric Acid

2013 ◽  
Vol 652-654 ◽  
pp. 669-672 ◽  
Author(s):  
Xiao Bao Han ◽  
Xiang Guo Li ◽  
Gui Hua Peng ◽  
Zhen Hua Liang ◽  
Xia Wang
Keyword(s):  
Citric Acid ◽  
Luminescent Properties ◽  
Combustion Method ◽  
Molar Ratio ◽  
Hexagonal Crystal Structure ◽  
X Ray Diffraction ◽  
Hexagonal Crystal ◽  
Red Emission ◽  
X Ray ◽  
Structure Morphology

Nanocrystalline Y2O2S: Eu3+, Mg2+, Ti4+red long-lasting phosphor was synthesized successfully by combustion method using thiourea and citric acid as fuel. The structure, morphology and luminescent properties of these phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). The experimental results revealed that the phosphor was composed of sheet-shaped Y2O2S with hexagonal crystal structure. They exhibited strong red emission at 617 nm and 626nm. In addition, the dosage of citric acid has great effect on the phosphor. When molar ratio of citric acid to Y3+is 1.3, the resulted phosphor gives the highest emission intensity.

Molten Salt Synthesis of SnS2 Nanoparticles with Visible-Light Driven Photocatalytic Activity for the Degradation of Rhodamine B

2015 ◽  
Vol 655 ◽  
pp. 203-207 ◽  
Author(s):  
Tie Kun Jia ◽  
Guang Sun ◽  
Jian Liang Cao ◽  
Zhan Ying Zhang
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Molten Salt ◽  
Diffuse Reflectance ◽  
High Photocatalytic Activity ◽  
Molten Salt Synthesis ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Visible Light Driven

SnS2 nanoparticles with perfectly crystalline morphology were synthesized via a molten salt synthesis route at a relatively low temperature. The resulting SnS2 nanoparcticles were characterized by X-ray diffraction (XRD), field scanning electron microscopy (FESEM), and UV-vis diffuse reflectance spectra (UV-vis). The observations of FESEM images showed that the sample consists of a large number of aggregates assembled with numerous nanoparticles packed into compact texture. The photocatalytic activity of the as-prepared SnS2 samples was evaluated by the degradation of RhB aqueous solution. The effect of the molar ratio of thiourea to SnCl2 on the photocatalytic activity was also investigated, and the result showed that the as-prepared SnS2 sample has high photocatalytic activity efficiency in the degradation of RhB aqueous solution when the molar ratio of thiouea to SnCl2 was 3.

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

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