scholarly journals Vis and NIR Diffused Reflectance Study in Disordered Bismuth Manganate ‒ Lead Titanate Ceramics

2021 ◽  
Author(s):  
Andrzej Molak ◽  
Anna Z. Szeremeta ◽  
Janusz Koperski
Keyword(s):  
Activation Energy ◽  
Lead Titanate ◽  
Energy Gap ◽  
Conductivity Activation Energy ◽  
Optical Energy Gap ◽  
Munk Function ◽  
Light Reflectance ◽  
Optical Applications ◽  
Titanate Ceramics ◽  
Scanning Electron

This work shows a correlation between light reflectance, absorption, and morphologies of series of (1-x) BM–x PT, (x = 0.0, 0.02, 0.04, 0.08, 0.12, 0.16, 0.24) ceramics composite. The (1-x) BM–x PT showed features of a black mirror with a low optical energy gap. The measured Vis-NIR diffused reflectance enabled the calculation of the energy gap using the modified Kubelka-Munk function. The estimated energy gap was lower than 1.5 eV related to low reflectance in the Vis-NIR range. Moreover, obtained histograms of grains, using scanning electron microscope, enabled the correlation between grains size and amount of lead titanate. We deduced from the ceramics surface morphology that marked porosity also induced reflectivity of low magnitude. We correlated the magnitude of the energy gap with phases of the BM-PT composite and with the electrical conductivity activation energy reported in the literature. Our results findings opened prospect studied materials for optical applications.

scholarly journals Plasmonic nanostructures of SnO2:Sb thin film under gamma radiation response

2020 ◽  
Vol 38 (1) ◽  
pp. 62-72
Author(s):  
A. F. Maged ◽  
M. Amin ◽  
H. Osman ◽  
L.A. M. Nada
Keyword(s):  
Gamma Radiation ◽  
Thermal Annealing ◽  
Energy Gap ◽  
Negative Refractive Index ◽  
Spray Pyrolysis Technique ◽  
Radiation Response ◽  
Plasmonic Nanostructures ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
Optical Applications

AbstractThis paper is a part of a natural dye solar cell project. Conductive transparent oxide (CTO) films have been deposited onto preheated glass substrates using a spray pyrolysis technique. The optical, electrical, structural properties as well as thermal annealing and gamma radiation response were studied. The average optical energy gap of doped films for direct allowed and direct forbidden transitions were found to be 3.92 and 3.68 eV, respectively. The plasmon frequency and plasmon energy after doping were found to be 3.48 × 1014 s −1 and 0.23 eV. The negative absorbance of the doped film was observed in UV-Vis range after applying both thermal annealing and γ-dose irradiation with 22 kGy. The negative refractive index of the doped film in UV range (220 – 300 nm) is promising for optical applications. The electron mobility μe reached a maximum of 27.4 cm2 V−1 s−1 for Sb concentration of 10 %. The corresponding resistivity ρ, and sheet resistance Rs reached their minimum values of 1.1 × 10−3 Ω cm and 35 Ω sq−1, respectively. The dopant concentration has been increased from 4.13 × 1019 to 2.1 × 1020cm−3. The doped film was found to exhibit three diffraction peaks associated with (2 2 2), (2 0 0), and (2 1 1) reflection planes, of which the peak of (2 2 2) of Sb2O3 and the peak of (2 0 0) were very close.

scholarly journals The Physical and Optical Studies of Crystalline Silica Derived from the Green Synthesis of Coconut Husk Ash

2020 ◽  
Vol 10 (6) ◽  
pp. 2128 ◽  
Author(s):  
Muhammad Fahmi Anuar ◽  
Yap Wing Fen ◽  
Mohd Hafiz Mohd Zaid ◽  
Khamirul Amin Matori ◽  
Rahayu Emilia Mohamed Khaidir
Keyword(s):  
Green Synthesis ◽  
Acid Treatment ◽  
Energy Gap ◽  
Negative Effects ◽  
Optical Energy Gap ◽  
X Ray ◽  
Coconut Husk ◽  
Optical Applications ◽  
The Fourier Transform ◽  
Coconut Shells

The green synthesis of silica has been extensively explored over the last few decades, as silica compounds found in commercial products can cause negative effects on human health. This calls for alternative ways to produce silica that are safer, cheaper and more environmentally friendly. Some of the agricultural wastes proven to contain silica include rice husk, sugarcane bagasse, coconut shells and coconut husk. This paper describes the synthesis of silica from coconut husk waste, and its physical and optical properties for potential utilization in optical applications. Coconut husk was subjected to fire at 500–700 °C so as to form coconut husk ash (CHA), and was then treated with sulfuric acid to extract silica from the ash. Most of the weight degradation subsequently occurred at temperatures from 221 to 360 °C. X-ray fluorescence (XRF) analysis proved that 91.76% of the silica was obtained, while major peaks on the X-ray diffraction (XRD) spectrum were observed after the acid treatment. Chemical bonds such as Si-O-Si, CH2, -OH and Si-OH were found in the spectrum of the Fourier transform infrared spectroscopy (FTIR). Furthermore, the particles displayed rod-like shapes and irregular sizes, but the particle with sizes ranging from 200–750 nm decreased after the acid treatment. The relationship between the absorption coefficient and photon energy was obtained by finding the optical energy gap, which was found to be 4.3 eV. These data points provide critical information when used in optical applications. The overall studies show that synthesized silica has great potential for use in optical field applications.

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.

DEPENDENCE OF THE OPTICAL AND ELECTRICAL PROPERTIES OF CHEMICALLY ANNEALED VACUUM-DEPOSITED a-Si:H FILMS ON THE DEPOSITION RATE

2012 ◽  
Vol 27 (02) ◽  
pp. 1350015
Author(s):  
AHMED M. EL-NAGGAR
Keyword(s):  
Activation Energy ◽  
Electrical Properties ◽  
Deposition Rate ◽  
Room Temperature ◽  
Energy Gap ◽  
Dark Conductivity ◽  
Optical Parameters ◽  
Optical And Electrical Properties ◽  
Optical Energy Gap ◽  
Optical Energy

The influence of the deposition rate of chemically annealed vacuum-deposited a-Si : H films on its optical and electrical properties was studied. The optical parameters were studied using spectrophotometric measurements of the film transmittance in the wavelength range 200–3000 nm. It was found that with increasing the silicon deposition rate from 0.09 to 0.23 nm/s, the refractive index, n, decreases from 3.78 to 3.45 at 1.5 μm, and the optical energy gap, Eg, decreases from 1.74 to 1.66 eV, while the Urbach parameter, ΔE, increases from 77 to 99 meV. The dark conductivity was measured at temperatures descending from 480 to 170 K. It was found that the room temperature dark conductivity values decreased from 1.11 × 10-6 (Ω⋅ cm )-1 to 2.08 × 10-10 (Ω⋅ cm )-1 with increasing the deposition rate from 0.09 to 0.23 nm/s respectively, while the activation energy Ea increased from 0.53 to 0.84 eV with increasing deposition rate. As a result, a good quality a-Si : H film with optical energy gap of 1.74 eV, Urbach parameter of 77 meV, dark conductivity of 1.11 × 10-6 (Ω⋅ cm )-1, and activation energy of 0.53 eV was successfully prepared at a low deposition rate of 0.09 nm/s.

Effect of ZrO2 Doping on Crystal Structure, Microstructure and Phase Transition of Lead Titanate Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 169-172 ◽  
Author(s):  
Panadda Sittiketkron ◽  
S. Sukkho ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Lead Titanate ◽  
X Ray ◽  
Zro2 Phase ◽  
Ceramic Samples ◽  
Average Grain Size ◽  
Titanate Ceramics ◽  
Pbtio3 Ceramics ◽  
Scanning Electron

In this work, the effect of ZrO2 doping on the properties of PbTiO3 ceramics was investigated. PbTiO3 powders were prepared via a mixed oxide method with a calcination temperature of 750 °C for 2 h. The various amounts of ZrO2, between 0 and 2 wt.%, were added to the calcined powders to decrease the c/a ratio. The mixed powders were sintered at 1225 °C for 2 h. The samples were characterized using X–ray diffractrometer (XRD), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). It was showed that the ZrO2 phase was not detected in all of the powder and ceramic samples. The highest density in the ceramics was found in the sample with 0.5 wt.% of ZrO2. The average grain size slightly increased with the increase of ZrO2. The phase transition temperature from tetragonal ferroelectric to cubic paraelectric was about 465 to 466 °C for all sintered samples.

scholarly journals Synthesis and optimization of Novel Chitosan/Cellulose Acetate Natural Polymer Membrane for water treatment

2018 ◽  
Vol 14 (1) ◽  
pp. 5303-5311 ◽  
Author(s):  
M. Kamal ◽  
E.M. Abdelrazek ◽  
N.M. Sellow ◽  
A.M. Abdelghany
Keyword(s):  
Cellulose Acetate ◽  
Spectral Data ◽  
Energy Gap ◽  
Small Variation ◽  
Spectroscopic Techniques ◽  
Natural Polymer ◽  
Structural Variations ◽  
Optical Energy Gap ◽  
Electron Microscopic ◽  
Scanning Electron

Chitosan (Ch) and Cellulose Acetate (CA) natural polymer in addition to other samples with different mass fractions of Chitosan/Cellulose Acetate (Ch/CA) were synthesized via simple casting route. Prepared samples were studied using FT-IR and UV/vis spectroscopic techniques. Structural variations due to the process of blending were retraced using X-ray diffraction data (XRD) and morphological investigation using scanning electron microscopy (SEM). Obtained spectral data reveals compatibility and complexation between polymer constituents identified through presence of polymer characteristic peaks with small variation in both intensity and position along with change in the value of optical energy gap from UV optical absorption spectral data. XRD pattern indicate the semicrystalline nature of the studied sample with an observable change in the crystallinity. Moreover, scanning electron microscopic (SEM) micrographs reveals homogenous structure without any evidence for agglomerations nearly in all compositions.

Effect of the structural changes on the mechanical properties of the sintered films

2016 ◽  
Vol 12 (1) ◽  
pp. 4141-4144
Author(s):  
Garima Jain
Keyword(s):  
Crystallite Size ◽  
Lattice Constant ◽  
Structural Changes ◽  
Structural Investigation ◽  
Energy Gap ◽  
Lattice Parameter ◽  
Metal Chalcogenides ◽  
Optical Energy Gap ◽  
Tin Telluride ◽  
Physical Quantities

Polycrystalline films of tin telluride were prepared by sintering technique. The structural investigation of the films with different thicknesses enables to determine lattice parameter, crystallite size and strain existing in the films. The XRD traces showed that strain was tensile in nature. The crystallite size increases with thickness while strain decreases. Higher the value of tensile strain, larger is the lattice constant. The optical energy gap shows a descending nature with increasing strain and so with the lattice constant. Such an attempt made to delve into interdependence of basic physical quantities helps to explore the properties of SnTe and utilize it as an alternative to heavy metal chalcogenides in various technological applications.  

scholarly journals Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5970
Author(s):  
Nabil Al-Zaqri ◽  
Mohammed Suleiman ◽  
Anas Al-Ali ◽  
Khaled Alkanad ◽  
Karthik Kumara ◽  
...  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Structural Parameters ◽  
Population Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Td Dft

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2–sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

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