scholarly journals "The Effects of Additive TiO2 Nanoparticles on the Optical properties of DCM Doped with PVC Thin Films "

2018 ◽  
Vol 5 (1) ◽  
pp. 27-35
Author(s):  
Shymaa K. Hussian ◽  
Thill A. Kadhum Al-musaw ◽  
Shatha Raheem Helal Al himidi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Tio2 Nanoparticles ◽  
Electronic Transition ◽  
Transition Energy ◽  
Energy Gap ◽  
Sol Gel ◽  
Titania Nanoparticles ◽  
Absorption Region ◽  
Electronic Transition Energy

"In this work thin films containing laser dye (DCM) doped with (PVC) were prepared using casting method. Titania (TiO2) nanoparticles also were synthesized using sol-gel technique. Different titania nanoparticle densities (0.882×1020, 1.765×1020, 2.648×1020 and 3.530×1020 cm-3) were co-doping with dye doped polymer to study the effect of this addition on the optical properties and electronic transition energy gaps in cases of both direct and indirect transitions, Absorbance spectra were measured using Spectrophotometer. Absorption and extinction coefficients as well as the refractive indices have been obtained the spectra of absorbance at the strong absorption region. It was observed from results that the allowed direct electronic transitions energy gap was decreasing from 2.22 to 2.175e.V with the increasing of titania nanoparticles density and the allowed indirect electronic transition energy gap decreasing from 2.19 to 2.13e.V.

scholarly journals "Synthesis and Optical Properties of Polystyrene Doped with DCM Thin Films "

2018 ◽  
Vol 5 (1) ◽  
pp. 8-18
Author(s):  
Akeel Shaker Tuhaiwer
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Transition Energy ◽  
Energy Gap ◽  
Electronic Transitions ◽  
Effect Of Temperature ◽  
Casting Method ◽  
Double Beam ◽  
Urbach’S Energy ◽  
Electronic Transition Energy

"In the present work Polystyrene (PS) polymer doped with DCM laser dye thin films have been prepared on glass substrate using casting method. The final samples of PS doped with DCM thin films were treated with different annealing temperatures at (30, 40, 50, 60) oC. Optical absorption and transmission spectra of the prepared thin films were recorded using UV-VIS double beam spectrometer in the wavelength range from 190 to 1100 nm. The results shown that the allowed direct electronic transitions energy gap increased from 2.08 up to 2.25e.V as the temperature increasing from 30 to 60oC, whereas the allowed indirect electronic transition energy gap increase from 2.02 up to 2.17 eV as the temperature increase from 30 to 60oC. The effect of temperature on the optical properties such as Urbach’s energy, Refractive index, Extinction coefficient, Critical angle, Brewster angle, and Finesse coefficient of PS doped with DCM thin films also studied in this work.

INFLUENCE OF ROTATION RATE ON OPTICAL PROPERTIES OF ZnS THIN FILMS ANALYZED BY SPECTROSCOPIC ELLIPSOMETRY METHOD

2019 ◽  
Vol 27 (01) ◽  
pp. 1950092
Author(s):  
BATOOL AHMADI KHANEGAHI ◽  
HASSAN SEDGHI
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Energy Gap ◽  
Incidence Angle ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Glass Substrates ◽  
Rotation Rates ◽  
Zns Films

In the present work, zinc sulfide thin films were deposited on glass substrates by sol–gel process with different coating speeds 3600, 4800, 6000 and 7200[Formula: see text]rpm. Zinc acetate (Zn(CH3COO)[Formula: see text]H2O) and thiourea (CH4N2S) were used as precursors. Two-methoxyethanol and monoethanolamine were used as solvent and stabilizer, respectively. The optical properties of ZnS thin films such as refractive index, extinction coefficient, dielectric function and optical band gap energy of the films were obtained by spectroscopic ellipsometry (SE) analysis method in the wavelength range of 300–800[Formula: see text]nm. The incidence angle of the layers was kept at 70∘. The measured SE parameters [Formula: see text] and [Formula: see text] are fitted against the designed model by minimizing the mean square error (MSE). Considering the data obtained, it can be deduced that the optical properties of ZnS films are highly influenced by rotation rates. The extinction coefficients of the films were increased with increasing rotation rates of the films. From these results, it is found that the energy gap of the ZnS films increases with increasing rotation rates of the films in the range of 3.13–3.20[Formula: see text]eV.

scholarly journals The Effects of Additive TiO2 Nanoparticles on the Energy Gap of DCM Doped with PS Thin Films

2016 ◽  
Vol 68 ◽  
pp. 71-81
Author(s):  
Jafer Fahdel Odah
Keyword(s):  
Thin Films ◽  
Energy Gap ◽  
Sol Gel ◽  
Casting Method ◽  
Characteristic Peak ◽  
Co Doping ◽  
Energy Gaps ◽  
Gel Technique ◽  
Doped Polymer ◽  
Electronic Transition Energy

In this work thin films containing laser dye (DCM) doped with polystyrene (PS) were prepared using casting method. Titania (TiO2) nanoparticles also were synthesized using sol gel technique. Characteristics of the tetania were done using XRD patter, and the characteristic peak of anatase is sharper and clear to observe, in particular at 25.40° degree. While scanning electron microscopy (SEM) was used to achieve the morphology of TiO2samples, and to determine the sizes of nanoparticles. Different titania nanoparticle densities (0.882×1020, 1.765×1020, 2.648×1020, 3.530×1020and 4.413×1020cm-3) were co-doping with dye doped polymer and study the effect of this addition on the optical properties and electronic transition energy gaps in cases of both direct and indirect transitions.

Effects of annealing temperature on the structural and optical properties of ZnO thin films prepared by sol–gel method

2016 ◽  
Vol 09 (06) ◽  
pp. 1750010 ◽  
Author(s):  
Jitao Li ◽  
Dinyu Yang ◽  
Xinghua Zhu ◽  
Hui Sun ◽  
Xiuying Gao ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Sol Gel ◽  
Heat Treating ◽  
Zno Thin Films ◽  
Structural And Optical Properties ◽  
Gel Method ◽  
Sol Gel Method

ZnO thin films have been prepared by sol–gel method in this paper. Zinc acetate, ethanol and mono-ethanolamine (MEA) were used as a metal precursor, solvent and stabilizer, respectively. The structural and optical properties of ZnO thin films were investigated and found to be strongly dependent on the annealing temperature. X-ray diffraction patterns revealed that as the annealing temperature increased, the crystalline quality of the samples became better. The atomic force microscope images of the samples show larger and compact grains at higher heat-treating temperature. The ultraviolet–visible transmittance spectra indicated that as the temperature increased, the transmittance improved and the energy gap became larger (from 3.11[Formula: see text]eV at 400[Formula: see text]C to 3.22[Formula: see text]eV at 500[Formula: see text]C). The photoluminescence spectra presented a variety of emission peaks, two strong peaks at 390[Formula: see text]nm and 469[Formula: see text]nm, respectively, from the intrinsic emission and point defects, and the intensity of these peaks decreased with the increase of temperature.

scholarly journals Optical Study on Deposed Polystyrene Doped DCM Laser Dye Thin Films at Different Temperature

2016 ◽  
Vol 68 ◽  
pp. 39-47
Author(s):  
Akeel Shaker Tuhaiwer
Keyword(s):  
Thin Films ◽  
Transition Energy ◽  
Energy Gap ◽  
Electronic Transitions ◽  
Effect Of Temperature ◽  
Optical Study ◽  
Laser Dye ◽  
Casting Method ◽  
Annealing Temperatures ◽  
Electronic Transition Energy

Polystyrene (PS) polymer doped with DCM laser dye thin films have prepared on glass substrate using casting method. The obtained PS doped with DCM thin films were treated at different annealing temperatures such (30, 40, 50, 60, 70) °C. It was observed from result that the allowed direct electronic transitions energy gap was increased from 2.21 up to 2.3e.V as the temperature increasing from 30-70°C. And the allowed indirect electronic transition energy gap rose from 0.06 to 0.15e.V as the temperature increasing. The allowed indirect phonon energy also was decreased at the same range of temperature. The different effect of temperature variation was observed on the optical properties of PS doped with DCM thin films.

Annealing Temperature Dependence of Optical Properties of Sol-Gel ZnO Thin Films with Different Sol Aging Time

2017 ◽  
Vol 48 ◽  
pp. 211-217 ◽  
Author(s):  
Ji Tao Li ◽  
Ding Yu Yang ◽  
Xing Hua Zhu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Aging Time ◽  
Annealing Temperature ◽  
Urbach Energy ◽  
Energy Gap ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
Ultraviolet Emission

ZnO thin films on glass substrates have been successfully fabricated by sol-gel method for various aging time and annealing temperature. X-ray diffraction (XRD) patterns showed the crystallites at (100), (002) and (101) plane of hexagonal wurtzite structure. Atomic force microscope (AFM) images were used to investigate the surface morphology. The transmittance, energy gap, Urbach energy and photoluminescence (PL) of samples were investigated to explore the effects of annealing temperature on optical properties of ZnO thin films under different sol aging time. The transmittance spectra of thin films aged for 24 hours and 48 hours revealed the enhanced transmittance in visible region as rising annealing temperature, also, the optical band gap of the samples increased and Urbach energy decreased. The photoluminescence (PL) spectra of samples aged for 24 hours and 48 hours were studied and found the increased ultraviolet emission at ~387 nm, and various decreased visible emissions with rising annealing temperature. Nevertheless, the excessive sol aging time for 72 hours deteriorated the optical characteristics of thin films, resulting in that transmittance, energy gap and ultraviolet emission declined, and visible emissions increased with rising annealing temperature. The optical performances of the ZnO films aged for different time have no the same dependence of annealing temperature.

OPTICAL PROPERTIES OF THERMALLY EVAPORATED METAL-FREE PHTHALOCYANINE (H2Pc) THIN FILMS

2005 ◽  
Vol 19 (27) ◽  
pp. 4057-4071 ◽  
Author(s):  
M. M. EL-NAHASS ◽  
M. M. SALLAM ◽  
H. A. M. ALI
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Film Thickness ◽  
Energy Gap ◽  
Fundamental Absorption Edge ◽  
Absorption Region ◽  
Metal Free ◽  
Polycrystalline Form ◽  
Absorption Measurements

The optical properties of metal-free phtalocyanine ( H 2 Pc ) in thin film form is investigated. X-ray diffractograms of the ( H 2 Pc ) powder show that it has a α-polycrystalline form with a monoclinic structure. The thermal evaporation of ( H 2 Pc ) powder leads to α-polycrystalline films, oriented preferentially to the (001) plane. After annealing at 623 K for two hours, a mixture of α- and β-phases is formed on an amorphous background. The optical properties of ( H 2 Pc ) thin films have been studied using spectrophotometeric measurements of transmittance and reflectance in the range 200–2200 nm for a different film thickness. The refractive index and the absorption index show independence on the film thickness. The refractive index shows anomalous dispersion in the region of the fundamental absorption edge. The absorption measurements show the characteristic splitting of the Q-band and ΔQ is obtained as 0.22 eV. The absorption coefficient in the absorption region reveals indirect transitions. The fundamental and the onset energy gap are determined as 2.74 eV and 1.55 eV, respectively.

STRUCTURAL, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVITY OF NANOCRYSTALLINE TiO2 THIN FILMS DEPOSITED BY SOL-GEL SPIN COATING

2019 ◽  
Vol 7 (1) ◽  
pp. 28
Author(s):  
KOMARAIAH DURGAM ◽  
RADHA EPPA ◽  
REDDY M. V. RAMANA ◽  
KUMAR J. SIVA ◽  
R. SAYANNA ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Spin Coating ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Nanocrystalline Tio2

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

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