Influence of Organic Polymers as Capping Agent on Structural and Optical Properties of ZnS:Mn2+ and CdS Nanocrystals

2008 ◽  
Vol 8 (1) ◽  
pp. 301-308 ◽  
Author(s):  
Ashish K. Keshari ◽  
M. Kumar ◽  
Prashant K. Singh ◽  
Avinash C. Pandey
Keyword(s):  
Optical Properties ◽  
Photo Luminescence ◽  
Organic Polymers ◽  
Visible Absorption ◽  
Capping Agents ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Uv Visible ◽  
Organic Capping ◽  
Co Precipitation

We have synthesized the luminescent ZnS:Mn2+ and bare CdS nanocrystals by employing polyvinyl alcohol (PVA), citric acid (CA) and biotin as organic capping agents by chemical co-precipitation route. The synthesized materials were characterized by X-ray diffraction, small angle X-ray scattering and transmission electron microscopy for the structural analysis, while UV-Visible spectroscopy and photoluminescence (PL) for optical properties. The results show that all the three organic polymers have the same effect and are capable of controlling the growth of the nanoclusters. From UV-Visible absorption spectra, it was observed that different capping agents do not affect the band gap of ZnS:Mn2+ system as well, while capping effect clearly observed on PL properties of ZnS:Mn2+ system. We have observed a novel result that capping with biotin show excellent photo-luminescence as compared to capping of PVA and CA on ZnS:Mn2+-systems. On the other hand, the annealing of these systems leads to degradation of luminescence intensity.

Design and Optical Properties of Rare Earth-Based Mixed-Anions (O, S, F) Compounds

2002 ◽  
Vol 755 ◽  
Author(s):  
Damien Pauwels ◽  
Alain Demourgues ◽  
Alain Tressaud
Keyword(s):  
Optical Properties ◽  
Rare Earth ◽  
Solid State ◽  
Visible Absorption ◽  
X Ray ◽  
Solid State Route ◽  
Earth Environment ◽  
Fluorite Type ◽  
Uv Visible ◽  
Single Crystal Analysis

ABSTRACTRare earth-based mixed-anions (O, S, F) compounds have been prepared by solid state route. The structures have been determined on the basis of powder diffraction (X-ray/neutrons) refinement and/or single crystal analysis. They have been described as a stacking of [Sx] 2x- layers and fluorite type blocks. The evaluation of the rare earth environment (bondlength, number of neighbors) can be directly related to the bandgap and to the UV-visible absorption in the La-based compounds.

EFFECT OF RAPID THERMAL ANNEALING ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF ZnO NANORODS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 65-68 ◽  
Author(s):  
R. CHAKRABORTY ◽  
SOUMEN DHARA ◽  
P. K. GIRI
Keyword(s):  
Optical Properties ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Zno Nanorods ◽  
Mechanochemical Reaction ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Pl Spectra ◽  
Uv Visible

In this work, we have investigated the influence of rapid thermal annealing (RTA) on structural and optical properties of ZnO nanorods synthesized by a mechanochemical reaction route using a planetary ball mill for different reaction time durations. Optical properties of as-grown and RTA-annealed samples are studied by UV–visible absorption and photoluminescence (PL), while structural studies are performed using X-ray diffraction line profile analysis and transmission electron microscopy. X-ray diffraction pattern of each sample is accompanied by characteristic wurtzite peaks of zinc oxide and exhibits the decrease in full width half maxima of the peaks after RTA. Williamson–Hall plot of each pattern is done to correlate the effect of strain of as-synthesized and RTA-treated samples. UV–visible absorption spectra show distinct redshift of excitonic absorption peaks with respect to those of as-synthesized samples. Interestingly, in PL spectra, the broad visible emission peaks observed for as-synthesized samples are eliminated completely for annealed samples. However, some of the constituent peaks in the UV–blue region of the PL spectra redshifted due to the grain growth and strain reduction.

scholarly journals Optical properties for TiO2 / PMMA nanocomposite thin films prepared by plasma jet

2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Titanium Oxide ◽  
Absorption Spectra ◽  
Plasma Jet ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Nanocomposite Thin Films ◽  
Uv Visible

PMMA/TiO2 homogeneous thin films were deposited by using plasma jet system under normal atmospheric pressure and room temperature. PMMA/TiO2 nanocomposite thin film synthesized by plasma polymerization. Titanium oxide was mixed with Methyl Methacrylate Monomer (MMA) with specific weight ratios (1, 3 and 5 grams of TiO2 per 100 ml of MMA). Optical properties of PMMA/TiO2 nanocomposite thin films were characterized by UV-Visible absorption spectra using a double beam UV-Vis-NIR Spectrophotometer. The thin films surface morphological analysis is carried out by employing SEM. The structure analysis are achieved by X-ray diffraction. UV-Visible absorption spectra shows that the increasing the concentration of titanium oxide added to the polymer leads to shift the peak position (λmax) toward the infrared region of the electromagnetic spectrum. Also the peak width increases when the concentration of TiO2 increases. It can be controlled optical energy band gap of PMMA/TiO2 nanocomposite thin films by changing concentration of TiO2. SEM indicate a uniform distribution of titanium oxide particles in PMMA matrix. The x-ray diffraction pattern indicated that the thin films have amorphous structure.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

Synthesis and Characterizations of Nanocubes, Monodispersed Nanocrystals and Nanospheres of Au

2007 ◽  
Vol 353-358 ◽  
pp. 2163-2166
Author(s):  
Ming Yang ◽  
Guo Qing Zhou ◽  
Jiang Guo Zhao ◽  
Zhan Jun Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Scherrer Formula ◽  
Visible Absorption Spectroscopy

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were estimated by Debye-Scherrer formula according to XRD spectrum.

Photoactive amphiphiles for the assembly of supramolecular architectures

2015 ◽  
Vol 185 ◽  
pp. 471-479 ◽  
Author(s):  
B. P. Jarman ◽  
F. Cucinotta
Keyword(s):  
Visible Spectrum ◽  
Solid Materials ◽  
Visible Absorption ◽  
Optical Components ◽  
Absorption And Emission ◽  
X Ray ◽  
Supramolecular Architectures ◽  
Uv Visible ◽  
Absorption And Emission Spectroscopy ◽  
Molecular Organisation

The presented study reports the use of photoactive templating structures for the design of porous frameworks with built-in optical functionalities. The materials have been synthesised and characterised using powder X-ray diffractometry, UV-visible absorption and emission spectroscopy. The latter shows that, by varying the relative amount of an amphiphilic chromophore in the micellar templates, it is possible to tune the light absorption and emission properties over the visible spectrum, by means of controlling the molecular organisation and the excitonic coupling of aggregated species. This enables versatile solid materials that can be used as optical components for light-harvesting and converting systems to be obtained .

Syntheses and crystal structures of guanidine hydrochlorides with two Schiff base functions as efficient colorimetric and selective sensors for fluoride

2018 ◽  
Vol 73 (8) ◽  
pp. 601-609 ◽  
Author(s):  
Bei Wang ◽  
Pei-Zhi Zhang ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Optical Properties ◽  
Schiff Base ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Guanidinium Chloride ◽  
Visible Absorption ◽  
X Ray ◽  
Color Changes ◽  
Base Functions ◽  
Magnetic Resonances

AbstractA series of guanidinium chloride derivatives have been synthesized by condensation of 1,3-diaminoguanidine monohydrochloride with heteroaromatic formaldehydes in good yields. All compounds were characterized by nuclear magnetic resonances and infrared spectroscopies, and the molecular structures of four compounds were determined by single crystal X-ray diffraction. The optical properties of these guanidinium chloride derivatives with fluoride anions were investigated, showing selective color changes from colorless to yellow or orange, red-shifted in the ultraviolet/visible absorption spectra.

Structural and Optical Properties of TiO2 Thin Films Prepared by Thermal Oxidation of Ti Thin Films

2013 ◽  
Vol 770 ◽  
pp. 225-228
Author(s):  
L. Uttayan ◽  
K. Aiempanakit ◽  
M. Horprathum ◽  
P. Eiamchai ◽  
V. Pattantsetakul ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Thermal Oxidation ◽  
Annealing Temperature ◽  
Oxidation Process ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Wafer Substrate ◽  
Uv Visible ◽  
Ti Films

Titanium dioxide (TiO2) films were prepared by thermal oxidation from Ti films. The Ti films were deposited on glass and silicon (100) wafer substrate by dc magnetron sputtering and subsequent with thermal oxidation process. The crystal structure and morphology of TiO2 films were estimated by using X-ray diffractometry (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The optical property of TiO2 films was determined by UV-Visible spectrophotometer. The influences of annealing temperature between 200 to 500°C in air for 1 hour on the structure and optical properties of TiO2 films were investigated. The increasing of annealing temperature was directly affected the phase transition from Ti to TiO2. The optical and structural properties of TiO2 films are the best exhibited with increasing the annealing temperature at 500 °C.

Structural and optical properties of Ba(Co1−xZnx)SiO4 (x = 0.2, 0.4, 0.6, 0.8)

2019 ◽  
Vol 34 (3) ◽  
pp. 242-250 ◽  
Author(s):  
J. Anike ◽  
R. Derbeshi ◽  
W. Wong-Ng ◽  
W. Liu ◽  
D. Windover ◽  
...  
Keyword(s):  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Visible Absorption ◽  
X Ray ◽  
Lattice Volume ◽  
Uv Visible ◽  
Diffraction Patterns ◽  
Pattern Determination ◽  
Bright Blue

Structural characterization and X-ray reference powder pattern determination have been conducted for the Co- and Zn-containing tridymite derivatives Ba(Co1−xZnx)SiO4 (x = 0.2, 0.4, 0.6, 0.8). The bright blue series of Ba(Co1−xZnx)SiO4 crystallized in the hexagonal P63 space group (No. 173), with Z = 6. While the lattice parameter “a” decreases from 9.126 (2) Å to 9.10374(6) Å from x = 0.2 to 0.8, the lattice parameter “c” increases from 8.69477(12) Å to 8.72200(10) Å, respectively. Apparently, despite the similarity of ionic sizes of Zn2+ and Co2+, these opposing trends are due to the framework tetrahedral tilting of (ZnCo)O4. The lattice volume, V, remains comparable between 626.27 Å3 and 626.017 (7) Å3 from x = 0 to x = 0.8. UV-visible absorption spectrum measurements indicate the band gap of these two materials to be ≈3.3 and ≈3.5 eV, respectively, therefore potential UV photocatalytic materials. Reference powder X-ray diffraction patterns of these compounds have been submitted to be included in the Powder Diffraction File (PDF).

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