Spectroscopic Studies of Polypyrrole - PVA Reinforced Iraqi Bentonite Clay Composites

2021 ◽  
Vol 19 (11) ◽  
pp. 151-157
Author(s):  
Shaymaa Hadi Al-Rubaye ◽  
Eman Hammod Abdullah ◽  
Amar Al-Keisy
Keyword(s):  
Particle Size ◽  
Energy Gap ◽  
Wave Length ◽  
Bentonite Clay ◽  
Spectroscopic Studies ◽  
Optical Energy Gap ◽  
Weight Percentage ◽  
Length Increase ◽  
Vis Spectroscopy ◽  
Composite Samples

The mixture of Polypyrrole solution with polyvinyl alcohol reinforced Iraqi Bentonite clay are used for preparing a composite that investigated in this study. The weight percentage of bentonite used is 5, 10, 15, and 20 and the particle size selected is less than 75 μm. Composite samples prepared has a thickness of 0.15mm and dimensions of 2.6×2.8 cm2. The optical properties of polymer composites were studied using UV-Vis spectroscopy. The values of optical energy gap decreased from 5.44, 5.41, 5.38 and 5.28 eV for the 5, 10, 15, and 20 wt% of bentonite respectively, and the absorption coefficient increased. The extinction coefficient increases with increasing additive bentonite and decreases as the incident wave length increase. The present work is very important for tailoring the optical response of Polypyrrole – bentonite composites according to specific requirements.

scholarly journals Optical and A.C. Electrical Properties for Polypyrrole and Polypyrrole/Graphene (ppy/gn) Nanocomposites

2021 ◽  
Vol 19 (51) ◽  
pp. 72-78
Author(s):  
Fatima Mikdad Ahmed ◽  
Salma M. Hassan
Keyword(s):  
Electrical Properties ◽  
Energy Gap ◽  
In Situ Polymerization ◽  
Wave Length ◽  
Chemical Oxidation ◽  
Optical Energy Gap ◽  
Vis Spectroscopy ◽  
Order Of Magnitude ◽  
Graphene Nanoparticles

In this work, chemical oxidation was used to polymerize conjugated polymer "Polypyrrole" at room temperature Graphene nanoparticles were added by in situ-polymerization to get (PPY-GN) nano. Optical and Electrical properties were studied for the nanocomposites. optical properties of the nanocomposites were studied by UV-Vis spectroscopy at wavelength range (200 -800 nm). The result showed optical absorption spectra were normally determined and the result showed that the maximum absorbance wave length at 280nm and 590nm. The optical energy gap has been evaluated by direct transition and the value has decreased from (2.1 eV for pure PPy) to (1.3 eV for 5 %wt. of GN). The optical constants such as the band tail width ΔE was evaluated, the value of ΔE for pure PPy was (0.0949eV) while for 5 wt. % of GN it was (0.5156 eV), It has been observed that the Urbach tail for pure PPy was smaller than that for PPy/GN nanocomposites and it increase as GN concentration increases. The A.C electrical conductivity at range of frequency (103Hz-106Hz) was increased by increasing the frequency and GN concentration about four order of magnitude. The s value was about (0.653-0.962) which means that the mechanism of conductivity is correlated hopping mechanism (C. H. P.). The dielectric constant and dielectric lose were determined and found to decrease with increasing frequency.

scholarly journals High-responsivity hybrid α-Ag2S/Si photodetector prepared by pulsed laser ablation in liquid

2020 ◽  
Vol 11 ◽  
pp. 1596-1607
Author(s):  
Raid A Ismail ◽  
Hanan A Rawdhan ◽  
Duha S Ahmed
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Laser Ablation ◽  
Energy Gap ◽  
Longitudinal Optical Phonon ◽  
Ambient Conditions ◽  
Optical Energy Gap ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Scanning Electron

We report the synthesis of α-Ag2S nanoparticles (NPs) by one-step laser ablation of a silver target in aqueous solution of thiourea (Tu, CH4N2S) mixed with cationic cetyltrimethylammonium bromide (CTAB) as surfactant. The effect of the CTAB surfactant on the structural, morphological, optical, and elemental composition of Ag2S NPs was evaluated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV–vis spectroscopy. The optical absorption decreased and the optical energy gap of α-Ag2S increased from 1.5 to 2 eV after the CTAB surfactant was added to the Tu solution. XRD studies revealed that the synthesized Ag2S NPs were polycrystalline with a monoclinic structure and that crystallinity of the nanoparticles was improved after adding CTAB. Raman studies revealed the presence of peaks related to Ag–S bonds (Ag modes) and the longitudinal optical phonon 2LO mode. Scanning electron microscopy investigations confirmed the production of monodisperse Ag2S NPs when using the CTAB surfactant. The optoelectronic properties of α-Ag2S/p-Si photodetector, such as current–voltage characteristics and responsivity in the dark and under illumination, were also improved after using the CTAB surfactant. The responsivity of the photodetector increases from 0.64 to 1.85 A/W at 510 nm after adding CTAB. The energy band diagram of the α-Ag2S/p-Si photodetector under illumination was constructed. The fabricated photodetectors exhibited reasonable stability after three weeks of storage under ambient conditions with a responsivity of 70% of the initial value.

scholarly journals Influence of Cr2O3 Nanoparticles on the Structural, Optical, Thermal and Electrical Properties of PEO/CMC Nanocomposites

2021 ◽  
Author(s):  
Laila Gaabour
Keyword(s):  
Energy Gap ◽  
Average Particle Size ◽  
Nanocomposite Films ◽  
Average Particle ◽  
Cole Plot ◽  
Optical Energy Gap ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Cr2o3 Nanoparticles ◽  
A Charge

Abstract In the present paper, different concentrations of chromium oxide (Cr2O3) nanoparticles were incorporated within PEO/CMC polymer blend to produce nanocomposite films using the casting method. The X-ray diffraction was performed on PEO/CMC-Cr2O3 nanocomposites. The main X-ray peaks of Cr2O3 were observed and defined as cubic structure and orthorhombic shape with an average particle size of the Cr2O3 ~ 50-80 nm. The decrease of some IR bands after the addition of Cr2O3 nanoparticles was found attributed to the interactions between PEO/CMC and Cr2O3. Effect of Cr2O3 nanoparticles on optical properties such as absorbance and optical energy gap (Eg) were characterized using UV-Vis spectroscopy. The Eg was reduced after the addition of Cr2O3 nanoparticles. The AC conductivity (sac), dielectric constant (ε′), dielectric loss (ε′′) and the dielectric modulus (M′ and M′′) were calculated at frequency range 0.1 Hz-7 GHz. The increases of direct conductivity (σdc) imply that the free charge density or of the charge mobility that results. The estimated values of both ε′ and ε′′ were decreased with increases of frequency. The addition of Cr2O3 nanoparticles causes the formation of a charge-transfer complex. The Cole-Cole plot between (M′ and M′′) shows a semi-circular shape confirm discuses according to a non‐Debye method.

scholarly journals Enhancement of vanadium oxide doped Eu+3 for gas sensor application

2019 ◽  
Vol 15 (33) ◽  
pp. 17-27
Author(s):  
Hassan M. Odhaib
Keyword(s):  
Thin Films ◽  
Response Time ◽  
Vanadium Oxide ◽  
Energy Gap ◽  
Average Frequency ◽  
Europium Oxide ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
X Ray ◽  
Vis Spectroscopy

Thin films of vanadium oxide nanoparticles doped with different concentrations of europium oxide (2, 4, 6, and 8) wt % are deposited on glass and Si substrates with orientation (111) utilizing by pulsed laser deposition technique using Nd:YAG laser that has a wavelength of 1064 nm, average frequency of 6 Hz and pulse duration of 10 ns. The films were annealed in air at 300 °C for two hours, then the structural, morphological and optical properties are characterized using x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy respectively. The X-ray diffraction results of V2O5:Eu2O3 exhibit that the film has apolycrystalline monoclinic V2O5 and triclinic V4O7 phases. The FESEM image shows a homogeneous pattern and confirms the formation of uniform nanostructures on the glass substrate. The type of the particle found nanoparticles with different doping concentrations of Eu2O3. The optical energy gap increases with the increase of doping concentration and it varies from 2.67 eV to 2.71 eV. The prepared thin films are used to fabricate sensor against nitrogen dioxide gas. The dependence of sensitivity and response time on doping ratio and operation temperature of gas sensors has been studied, the maximum sensitivity was about 100%, the response time is equal to 24s and recovery time 16s for V2O5 doped 2% Eu2O3 at 50 °C.

scholarly journals Spectroscopic analysis of CdCl2 doped PVA–PVP blend films

2017 ◽  
Vol 95 (8) ◽  
pp. 738-747 ◽  
Author(s):  
Basavarajeshwari M. Baraker ◽  
Blaise Lobo
Keyword(s):  
Fourier Transform ◽  
Photo Luminescence ◽  
Spectroscopic Studies ◽  
Intermediate Energy ◽  
Energy Bands ◽  
Weight Percentage ◽  
Blend Films ◽  
Optical Absorbance ◽  
Fourier Transform Raman Spectroscopy ◽  
Vis Spectroscopy

The changes in molecular chemical structure of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), caused by doping PVA–PVP blend with cadmium chloride (CdCl2), have been studied using ultraviolet–visible (UV-Vis) spectroscopy, Fourier transform Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The formation of cadmium nano-structures and microstructures in CdCl2-doped PVA–PVP blend has been visualized using scanning electron microscopy, in the range of doping levels varying from 0.5 up to 10.2 wt% (doping level in weight percentage). The incorporation of dopant in PVA–PVP blend is confirmed using energy dispersive X-ray spectroscopy. The optical absorbance (UV-Vis) spectra of PVA–PVP blend films doped with CdCl2 from 0.5 up to 2.2 wt%, showed a prominent absorption hump with peak at the wavelength 370 nm, in addition to other intermediate energy bands caused by the interactions of CdCl2 with molecules of PVA and PVP. The photo-luminescence (emission and fluorescence) spectra show significant quenching of fluorescence in CdCl2-doped PVA–PVP blend films. Analysis of FTIR and Raman spectra suggest the possible modes of interaction of cadmium ions (Cd2+) and chlorine ions (Cl−) with reactive functional groups (C–N, hydroxyl and carbonyl groups) of polymeric molecules in the blend. A reaction scheme for interaction of CdCl2 with PVA–PVP blend is proposed, on the basis of spectroscopic studies on these films.

scholarly journals Novelty Au Nanoparticles with Different Nano Sizes as an Acidity Sensor

2021 ◽  
Vol 31 (3) ◽  
pp. 167-173
Author(s):  
Zehraa Najim Abdul-Ameer
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Energy Gap ◽  
Uv Spectroscopy ◽  
Ph Sensor ◽  
Spherical Shape ◽  
Optical Energy Gap ◽  
Covalent Bonds ◽  
Wide Range

The amazing wide range, applications of gold nanoparticles corresponding to excellent optical and electronic properties enhance utilization of Au NP as PH sensor. Gold nanoparticles were synthesized in simple and rapid Turkevich method to accomplish optical sensing technologies covalent or non-covalent, bonds formation causes, aggregation of the nanoparticles in the target substance. Au nanoparticles characterization was studied using XRD, UV-spectroscopy and SEM. XRD indicate polycrystalline. Nanoparticles with two different sizes according to reducing agent amount to obtain 20 30 nm. Optical energy gap was calculated for both particle size to find it (2.13) eV for 30nm particle size and (2.33) eV for 20nm.Scanning Electron Microscope showed spherical shape particles. PH test were performed to investigate efficiency of Au Np’s for PH sensor and that is found to be excellent results for both sizes with more efficiency for 30 nm due to its rough surface. Which is a fantastic tool and measurement device to test the pH of soil, food, and other puncture-worthy applications.

scholarly journals Structural and optical studies of TiO2:Ag2O nanocomposite by sol-gel method

2020 ◽  
Vol 38 (2) ◽  
pp. 263-270
Author(s):  
Vaibhav Koutu ◽  
Rajesh Dhakar ◽  
Pragya Ojha ◽  
Lokesh Shastri ◽  
M.M. Malik
Keyword(s):  
Particle Size ◽  
Crystallite Size ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Crystallite Size ◽  
Wide Band ◽  
Spectroscopic Studies ◽  
Memory Storage ◽  
Average Particle ◽  
Vis Spectroscopy

AbstractAs TiO2 is suitable for electronic and electrical applications, in the present work the authors have successfully modified TiO2 by adding silver (Ag) to form titanium oxide-silver oxide (TiO2:Ag2O) nanocomposite samples by using sol-gel technique. Characterizations of these composites have been performed using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and UV-Vis spectroscopy. XRD study revealed that the crystal structure of the samples consisted of tetragonal and cubic phases. This study further showed an increment in the average crystallite size from 8 nm to 38 nm with an increase in Ag concentration. The increase in crystallite size has been confirmed additionally by SEM and AFM. The increment in the average particle size of the samples may be attributed to an increase in silver molarity in the TiO2 matrix. Significant red shift in the absorption edge has been observed, causing reduction in the energy bandgap of the composites from 3.89 eV to 3.46 eV with an increase in particle size which is evident from UV-Vis spectroscopic studies. This wide-band gap properties of the TiO2:Ag2O nanocomposite make it suitable for memory-storage devices and dielectric applications.

scholarly journals Influence of the Yttria and Graphite Particles on the same of Al 2024 Alloy Properties

2019 ◽  
Vol 26 (4) ◽  
pp. 1-7
Author(s):  
Raed Razooqi ◽  
Ahmed Akbar ◽  
Mohanad Hamada
Keyword(s):  
Particle Size ◽  
Wear Rate ◽  
Bulk Density ◽  
Mean Value ◽  
Metal Powders ◽  
Micro Hardness ◽  
Weight Percentage ◽  
Weight Content ◽  
Al 2024 ◽  
Composite Samples

Powders have been mixed as (Al with 99% purity ≤53µm particle size, Cu with 99.5% purity ≤53µm particle size, Mg with 99.5% purity ≤53µm particle size, Y2O3 with 99.9% purity ≤53µm particle size, Gr with 99.9% purity ≤53µm particle size). one set of composite samples was prepared by addition (3wt%Gr) to metal powders shown above. For the each sample of composite varying (Y2O3) weight percentage as: (Al 2024-3wt%Gr-XY2O3) was added x=(0,2,4,6,8)(wt%) the other set of composite was in opposite. Well mixed samples was pressed uniaxial with (700Mpa) and (30sec). the compacted samples were sintered at (6000C) for (2hr). Results have shown an increase in bulk density by (5.3%) for (Al 2024-3wt% Gr-XY2O3) with the increase of reinforcement until (8wt%) of (Y2O3), while bulk density have been reduced for (Al 2024-3wt%Y2O3-XGr) with (5%) with the increase of (Gr) weight content in the composite. An increase in real porosity was noticed with the increase of (Y2O3) with (8wt%) (11.9%) for (Al 2024-3wt%Gr-XY2O3) but this was less in comparison with (Al 2024-3wt%Y2O3-XGr) were porosity increase with the increase of (Grwt%) up to reduced (18.5%) at (8wt%Gr).Mean value was of micro hardness decreased gradually with the increase of (Grwt%) to reach (19.4%) reduction at (8wt%Gr) in opposite the micro hardness mean value increased by (20%) as (Y2O3wt%) increased to (8wt%).Compression strength have was increased by (51%) as (Y2O3) content increased from (2-8)(wt%) for (Al 2024-3wt%Gr-XY2O3) composite, while it was decreased by (48%) with the addition of (8wt%) graphite to (Al 2024-3wt%Y2O3-XGr).The content of (Gr) had higher effect on wear rate than (Y2O3) where the wear rate decreased by (59.7%) and (41%) for composite samples respectively, within the limits of addition in the current study.

scholarly journals Antibacterial and Energy Gap Correlation of PVA/SA Biofilms Doped With Selenium Nanoparticles

2020 ◽  
Vol 10 (5) ◽  
pp. 6236-6244
Keyword(s):  
Spectral Data ◽  
Pathogenic Bacteria ◽  
Energy Gap ◽  
Selenium Nanoparticles ◽  
Structural Variations ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Spectral Bands ◽  
Vis Spectroscopy ◽  
Ft Ir

Polymeric thin biofilms of polyvinyl alcohol (PVA)/sodium alginate (SA) doped with a different mass fraction of synthesized selenium nanoparticles were successfully synthesized using traditional solution casting routine. Obtained samples were studied for their structural variations using Fourier transform infrared (FT-IR), and ultravilot/visible (UV/Vis.) spectroscopy. FT-IR spectral data reveals the appearance of spectral bands characterized the functional groups of both PVA and SA structural units in their positions. UV/vis. spectral data was employed to calculate the optical energy gap of prepared samples. Antibacterial tests against pathogenic bacteria were performed and correlated to the optical energy gap.

scholarly journals Studying The Optical Properties of CdO and CdO: Bi Thin Films

2016 ◽  
Vol 13 (3) ◽  
pp. 593-598
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Energy Gap ◽  
Spray Pyrolysis Technique ◽  
Wave Length ◽  
Cadmium Oxide ◽  
Chemical Spray Pyrolysis ◽  
Optical Energy Gap ◽  
Chemical Spray ◽  
Before And After ◽  
20 Nm

Cadmium Oxide and Bi doped Cadmium Oxide thin films are prepared by using the chemical spray pyrolysis technique a glass substrate at a temperature of (400?C) with volumetric concentration (2,4)%. The thickness of all prepared films is about (400±20) nm. Transmittance and Absorbance spectra are recorded in the wave length ranged (400-800) nm. The nature of electronic transitions is determined, it is found out that these films have directly allowed transition with an optical energy gap of (2.37( eV for CdO and ) 2.59, 2.62) eV for (2% ,4%) Bi doped CdO respectively. The optical constants have been evaluated before and after doping.

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