Iraqi Journal of Physics

In this work, polyvinylpyrrolidone (PVP)/ Multi-walled carbon
nanotubes (MWCNTs) nanocomposites were prepared with two
concentrations of MWCNTs by casting method. Morphological,
structural characteristics and electrical properties were investigated.
The state of MWCNTs dispersion in a PVP matrix was indicated by
Field Effect-Scanning Electron Microscopy (FESEM) which showed
a uniform dispersion of MWCNTs within the PVP matrix. X-ray
Diffraction (XRD) indicate strong bonding of carbonyl groups of
PVP composite chains with MWCNTs. Fourier transfer infrared
(FTIR) studies shows characteristics of various stretching and
bending vibration bands, as well as shifts in some band locations and
intensity changes in others. Hall effect was studied to test the type of
charge carriers which was shown to be P-type. The electrical
conductivity was shown increased for the pure PVP and pure
MWCNT from (2.047×10-5) (Ω.cm)-1 and (3.683×101) (Ω.cm)-1 to
(2.51×102 and 2.36×102) (Ω.cm)-1for both concentrations of
nanocomposites, which indicate the conductivity was enhancement
by using the carbon nanotubes.

Groundwater can be assessed by studying water wells. This study
was conducted in Al-Wafa District, Anbar Governorate, Iraq. The water
samples were collected from 24 different wells in the study area, in
January 2021. A laboratory examination of the samples was conducted.
Geographical information systems technique was relied on to determine
the values of polluting elements in the wells. The chemical elements that
were measured were [cadmium, lead, cobalt and chromium]. The output
of this research were planned to be spatial maps that shows the
distribution of the elements with respect to their concentrations. The
results show a variation in the heavy elements concentrations at the
studied area groundwater. The samples show different values of
concentrations; for Cadmium (0.218-1.624) ppm, Lead (0.217-1.157)
ppm, Cobalt (0.014-0156) ppm, and for Chromium (0.045-0263) ppm.
The distribution of the materials concentrations differs for each element
which is refer to the sources of pollution are not relate to industry, but
it could be relate to fertilization.

In the present work polymer electrolytes were formulated using the
solvent casting technique. Under special conditions, the electrolyte
content was of fixed ratio of polyvinylpyrolidone (PVP):
polyacrylonitrile (PAN) (25:75), ethylene carbonate (EC) and propylene
carbonate (PC) (1:1) with 10% of potassium iodide (KI) and iodine
I2 = 10% by weight of KI. The conductivity was increased with the
addition of ZnO nanoparticles. It is also increased with the temperature
increase within the range (293 to 343 K). The conductivity reaches
maximum value of about (0.0296 S.cm-1) with (0.25 g) ZnO. The results
of FTIR for blend electrolytes indicated a significant degree of
interaction between the polymer blend (PVP and PAN) and the KI salt.
From the electrolyte observations of the nanocomposites, the broad peak
became narrower after adding the ZnO nanoparticle to the KI salt. The
dielectric reaction decreased with the increase of the frequency at room
temperature. The high dielectric permittivity of the polymer at lower
frequencies can be attributed to the dipoles having sufficient time to get
aligned with the electric field, resulting in higher polarization.

The present work aims to fabricate n-i-p forward perovskite solar
cell (PSC) with structure (FTO/compact TiO2/compact TiO2/ MAPbI3
Perovskite/ hole transport layer/ Au). P3HT, CuI and Spiro-OMeTAD
were used as hole transport layers. A nano film of 25 nm gold layer
was deposited once between the perovskite (PSK) layer and the
electron transport layer (ETL), then between hole transport layer
(HTL) and the perovskite layer. The performance of the forwardperovskite solar cell was studied. The role of the electron transport
layer and the hole transport layer in the perovskite solar cell was
presented. The structural, morphological and electrical properties were
studied with X-ray diffractometer (XRD), field emission scanning
electron microscope (FE-SEM) and current-voltage (J-V)
characteristic curves, respectively. J-V curves revealed that the
deposition of the Au layer between the perovskite layer and electron
transport layer reduced the power conversion efficiency from 3% to
0.08% when one layer of C. TiO2 is deposited in the PSC and to 0.11%
with two layers of C. TiO2. Power conversion efficiency, with CuI as
the hole transport layer, showed an increase from 0.5% to 2.7% when
Au layer was deposited between PSK and CuI layers. Also, Isc
increased from 6.8 mA to 17.4 mA and Voc from 0.3 V to 0.5V. With
depositing Au layer between P3HT and PSK layers, the results showed
an increase in the efficiency from 1% to 2.6% and an increase in Isc
from 10.7 mA to 30.5 mA, while Voc decreased from 0.75 V to 0.5V.

In this research, Zinc oxide (ZnO)/epoxy nanocomposite was
synthesized by simple casting method with 2wt. % ZnO concentration.
The aim of this work was to study the effect of pH and composite dosage
on the photocatalytic activity of ZnO/ epoxy nanocomposite. Scanning
electron microscopy (SEM) technique images proof the homogeneous
distribution of ZnO nanoparticles in epoxy. A synthesized
nanocomposite samples were characterized by Fourier Transform
Infrared spectrometer (FTIR) measurements. Two spectra for epoxy and
2wt.% ZnO/epoxy nanocomposites were similar and there are no new
bonds formed from the incorporation of ZnO nanoparticles. Using HCl
and NaOH were added to Methylene blue (MB) dye (5ppm) to gat pH
values 3 and 8. The degradation of the dye was 90.816% were pH =8
after 180 min. under sun-light. The degradation was 6.131% were pH=3
after 240 min. under sun-light irradiation. It is found that the base
solution help in accelerating the photocatalytic process, pH with high
value provides greater concentration of hydroxyl ions which interact
with h+ to form hydroxyl radicals OH- that give an enhancement
degradation rate of dyes. The dose of ZnO was increased from 3g to 6g
with Methylene blue MB (5ppm) the degradation was 94.3755% after
240 min. under sun-light irradiation. This means that increasing the dose
of ZnO, the photocatalytic activity will be increased.

AlO-doped ZnO nanocrystalline thin films from with nano
crystallite size in the range (19-15 nm) were fabricated by pulsed
laser deposition technique. The reduction of crystallite size by
increasing of doping ratio shift the bandgap to IR region the optical
band gap decreases in a consistent manner, from 3.21to 2.1 eV by
increasing AlO doping ratio from 0 to 7wt% but then returns to grow
up to 3.21 eV by a further increase the doping ratio. The bandgap
increment obtained for 9% AlO dopant concentration can.be
clarified in terms of the Burstein–Moss effect whereas the aluminum
donor atom increased the carrier's concentration which in turn shifts
the Fermi level and widened the bandgap (blue-shift). The
engineering of the bandgap by low concentration of AlO dopant
makes ZnO: AlO thin films favorable for the fabrication of
optoelectronic devices. The optical constants were calculated and
was found to be greatly affected by the increasing the doping ratio.

Metal enhanced fluorescence (MEF) is an unequaled
phenomenon of metal nanoparticle surface plasmons, when light
interacts with the metal nanostructures (silver nanoparticles) which
result electromagnetic fields to promote the sensitivity of fluorescence.
This work endeavor to study the influence of silver nanoparticles on
fluorescence intensity of Fluoreseina dye by employment mixture
solution with different mixing ratio. Silver nanoparticles had been
manufactured by the chemical reduction method so that Ag NP layer
coating had been done by hot rotation liquid method. The optical
properties of the prepared samples (mixture solution of Fluoreseina
dye solutions and colloidal solution with 5 minutes prepared of Ag
NPs) tested by using UV-VIS absorption and Fluorescence
spectrophotometer. by using AFM, SEM testes, the structure of silver
nanoparticles had been estimated. the result of this work showed that
adding Ag NPs colloidal to Fluoreseina dye solution help get a
significant increase in the fluorescence intensity of this dye. this study
results show that its significant to recent related studies in MEF.

Pure cadmium oxide films (CdO) and doped with zinc were
prepared at different atomic ratios using a pulsed laser deposition
technique using an ND-YAG laser from the targets of the pressed
powder capsules. X-ray diffraction measurements showed a cubicshaped of CdO structure. Another phase appeared, especially in high
percentages of zinc, corresponding to the hexagonal structure of zinc.
The degree of crystallinity, as well as the crystal size, increased with
the increase of the zinc ratio for the used targets. The atomic force
microscopy measurements showed that increasing the dopant
percentage leads to an increase in the size of the nanoparticles, the
particle size distribution was irregular and wide, in addition, to
increase the surface roughness of the nanoparticles. An increase in the
zinc ratio also led to a decrease in the energy gap. While the Hall effect
measuring showed an increase in the concentration of charge carriers
and a decrease in their mobility with increasing the doping ratio.

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.

Nanostructure of chromium oxide (Cr2O3-NPs) with
rhombohedral structure were successfully prepared by spray pyrolysis
technique using Aqueous solution of Chromium (III) chloride CrCl3
as solution. The films were deposited on glass substrates heated to 450
°C using X-ray diffraction (XRD) shows the nature of polycrystalline
samples. The calculated lattice constant value for the grown Cr2O3
nanostructures is a = b = 4.959 Å & c = 13.594 Å and the average
crystallize size (46.3-55.6) nm calculated from diffraction peaks,
Spectral analysis revealed FTIR peak characteristic vibrations of
Cr-O Extended and Two sharp peaks present at 630 and 578 cm-1
attributed to Cr-O “stretching modes”, are clear evidence of the
presence of crystalline Cr2O3. The energy band gap (3.4 eV) for the
chromium oxide nanostructures was measured using the UV-VIS-NIR
Optical Spectrophotometer. It was found that by scanning electron
microscopy (SEM) and image results, there is a large amount of
nanostructure with an average crystal size of 46.3-55.6 nm, which
indicates that our synthesis process is a successful method for
preparing Cr2O3 nanoparticles.