Study of Electroluminescence in Cadmium Sulfide Polymer Nanocomposite Films

2017 ◽  
Vol 49 ◽  
pp. 181-189 ◽  
Author(s):  
Vikas Lahariya

Nanocrystalline cadmium sulfide/Polyvinyl alcohol composite films were prepared by chemical route using Cadmium acetate and hydrogen sulfide gas as cadmium and sulfur source respectively. Poly vinyl Alcohal (PVA) used as polymer matrix. The initially loading of cadmium precursor influences the size as well as photoluminescence and electroluminescence properties of the Composite film. The films were characterized by X Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and UV-Visible Absorption spectra. The X-ray Diffraction result showed that CdS nanocrystals embedded in polymer matrix were in a zinc blend cubic structure. The UV-Visible absorption spectra of composite film reveal the blue shift in the band gap energy with respect to CdS bulk (2.42eV) material owing to quantum confinement effect. The Photoluminescence emission spectra show the green light emission at 510 nm arising from the defects states due to excess of cadmium or sulfur anion vacancies. Electroluminescence study indicates enhanced emission with low turn on voltage for higher loading of cadmium in polymer matrix due to increased oscillator strength. When higher electric field is applied, light emission start due to acceleration collision mechanism by charge carries inside the composite film.

2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem

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.


2019 ◽  
Vol 34 (3) ◽  
pp. 242-250 ◽  
Author(s):  
J. Anike ◽  
R. Derbeshi ◽  
W. Wong-Ng ◽  
W. Liu ◽  
D. Windover ◽  
...  

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).


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.


2012 ◽  
Vol 502 ◽  
pp. 164-168
Author(s):  
Ling Xu ◽  
Han Mei Hu ◽  
Hai Yan Xu

Novel mace-like (wolf-teeth clubs) CdS nanostructures were successfully prepared on a large scale using CdCl2•2.5H2O and NH2CSNH2 as starting materials through a convenient mixed-solvothermal route. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. The experimental results reveal that the morphology of CdS products was greatly affected by the volume ratio of anhydrous ethanol and distilled water. The possible mechanism for the formation of mace-like CdS nanostructures is simply discussed.


2021 ◽  
Author(s):  
Nejeh Hannachi ◽  
Thierry ROISNEL ◽  
Faouzi HLEL

Abstract A new non-centrosymmetricorganotin (IV) hybrid compoundC5H14N2 [SnCl6] 2H2O was determined by single crystal X-ray diffraction at 150(2) K. Its crystal structure was solved by single crystal X-ray diffraction reveling that compound crystallizes in the orthorhombic system with Pbca space group with the following lattice parameters: a = 12.1486 (15) Å, b= 15.4571 (17) Å, c = 16.7610 (18) Å with Z = 8. The bonding between inorganic and organic entities in the compounds is realized by hydrogen bonding O−H…O ,O−H…Cl , NH • • • Cl, N-H…Cl and O−H…Cl. Finally,UV-visible absorption measurements exhibit two absorption bands (226 nm and 262 nm).The optical band gap (Eg) is deduced to be 3.46 Ev.


2019 ◽  
Vol 14 (11) ◽  
pp. 1523-1531
Author(s):  
Manjit Kaur ◽  
Rakesh Dogra ◽  
Narinder Arora ◽  
Navjeet Sharma ◽  
Rajesh Kumar

AC transport properties and dielectric response of sandwich geometry (Ag/CuPc/Ag) of CuPc(CuPc) thin films deposited using thermal evaporation technique have been studied within frequency range 1 Hz–10 KHz and in temperature range 303–383 K. Scanning electron microscope (SEM) investigations of these films reveal fiber like morphology. Crystalline natures of CuPc films have been characterized using X-ray diffraction for different temperatures. The molecular orientations in films for different substrate temperatures have been confirmed by Raman spectroscopy. The optical band gaps calculated from the UV–Visible absorption spectra is found to lie in the range 3.01–3.15 eV. Electrical conductivity of CuPc films increases with increase of temperature. The hole mobility values of CuPc films at different temperatures have been calculated using negative differential susceptance (–ΔB) technique. Both capacitance and dielectric constant have been found to decrease with the increase of frequency and temperature.


Clay Minerals ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 93-103 ◽  
Author(s):  
P. Pustková ◽  
Z. Klika ◽  
J. Preclíková ◽  
T. M. Grygar

AbstractThe aggregation of three cationic dyes (CD), crystal violet (CV), Nile blue (NB) and rhodamine B (RB) in aqueous solution was studied by visible absorption spectrophotometry and compared with methylene blue (MB). The distribution of the dye species (monomers, dimers, trimers, and tetramers) in aqueous solutions with different concentrations of dye was calculated using equilibrium stepwise aggregation constants Kn. These cationic dyes were intercalated into montmorillonite (SAz-1) and its reduced charge form (RC-SAz(210)) prepared by heating lithium montmorillonite (Li/SAz-1) at 210ºC. The fluorescence of fully saturated CD/SAz and low-CD loaded CD/RC-SAz(210) complexes was studied. Visible absorption spectra of CD aqueous solutions and visible absorption spectra and X-ray diffraction patterns (d001) of the CD/SAz and CD/RC-SAz( 210) solid complexes were obtained and evaluated. Large fluorescence intensities were found for CV/RC-SAz(210) and NB/RC-SAz(210) complexes in the same way as for the complex of methylene blue with reduced-charge montmorillonite MB/RCM(210) described previously.


2007 ◽  
Vol 119 ◽  
pp. 239-242 ◽  
Author(s):  
Xiao Li Zhang ◽  
Young Hwan Kim ◽  
Young Soo Kang

Core/shell structured TiO2/ZnO was synthesized in a basic aqueous solution through a simple hydrolyzing method. The powder X-ray diffraction (XRD) and transmission electron microscopy of the initial TiO2/ZnO powder showed diffraction peaks corresponding to the ZnO and TiO2 phase. The structure and thickness of ZnO shell (about 2.5 nm) coated TiO2 surface as thin layers or nanoclusters, depends upon the reactant concentration and the reaction time. The characteristics of the optical absorption were described by UV-visible absorption spectroscopy.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 763
Author(s):  
Pejman Hajipour ◽  
Abbas Bahrami ◽  
Maryam Yazdan Mehr ◽  
Willem Dirk van Driel ◽  
Kouchi Zhang

This paper investigates the photocatalytic characteristics of Ag nanowire (AgNW)/TiO2 and AgNW/TiO2/graphene oxide (GO) nanocomposites. Samples were synthesized by the direct coating of TiO2 particles on the surface of silver nanowires. As-prepared AgNW/TiO2 and AgNW/TiO2/GO nanocomposites were characterized by electron microscopy, X-ray diffraction, UV/visible absorption spectroscopy, and infrared spectroscopy. Transmission electron microscope (TEM) images confirmed the successful deposition of TiO2 nanoparticles on the surface of AgNWs. The photocatalytic activity of synthesized nanocomposites was evaluated using Rhodamine B (RhB) in an aqueous solution as the model organic dye. Results showed that synthesized AgNW/TiO2/GO nanocomposite has superior photocatalytic activities when it comes to the decomposition of RhB.


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