scholarly journals Оптические свойства и электронные характеристики празеодима и неодима в конденсированном состоянии

2021 ◽  
Vol 129 (7) ◽  
pp. 848
Author(s):  
Л.А. Акашев ◽  
Н.А. Попов ◽  
В.Г. Шевченко
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Optical Properties ◽  
Optical Constants ◽  
Liquid Metals ◽  
Infrared Region ◽  
Energy Losses ◽  
Liquid States ◽  
Ellipsometric Method ◽  
Band Conductivity

The optical properties of unoxidized surfaces of polycrystalline Pr and Nd films in the spectral range 0.4 - 2.6 μm are studied. Optical constants were measured by Beattie ellipsometric method. Dispersion dependences of the optical conductivity σ, the reflectivity R, imaginary and real parts of the dielectric constant ε1 and ε2, and the function of characteristic electron energy losses Im (ε) -1 were calculated using the obtained optical constants. The paper presents the optical properties of both films and liquid metals studied earlier. The electronic characteristics of praseodymium and neodymium in solid thin-film and liquid states are calculated using the results of measurements in the infrared region of the spectrum using the two-band conductivity model.

Optimization of Maximum VO2 Content in Polymorphous Oxides of Vanadium

2013 ◽  
Vol 538 ◽  
pp. 113-116 ◽  
Author(s):  
S.N. Svitasheva
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Optical Constants ◽  
Ellipsometric Method

Optical properties of thin films of vanadium thermally oxidized at air were studied by ellipsometric method using wavelength of He-Ne laser. Multipart composition of these films was revealed and method of optimization of technological conditions based on dynamic of changing optical constants near 68°C was developed.

scholarly journals Optical properties for prepared polyvinyl alcohol/ polyaniline/ ZnO nanocomposites

2018 ◽  
Vol 16 (36) ◽  
pp. 181-189
Author(s):  
Salma Mohamed H.
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Polyvinyl Alcohol ◽  
Polymer Blends ◽  
Optical Transmission ◽  
Optical Constants ◽  
Energy Gap ◽  
Direct Transition ◽  
Optical Energy Gap ◽  
Reflection Index

The optical energy gap and optical constants such as the reflective index, dielectric constant have been evaluated due to The optical transmission and UV-VIS absorption spectra have been recorded in the wavelength (200 - 1100 nm) for PVA/PANI polymer blends and PVA/PANI/ZnO nanocomposites with different concentrations of ZnO (0.02, 0.05, 0.07, 0.1and 0.2) wt %. The results indicate that the materials have allowed direct transition. The reflection index and dielectric constant are increase with wavelength

Optical Properties of Strongly Absorbing Media Determined by External Reflection Spectroscopy

1992 ◽  
Vol 46 (6) ◽  
pp. 1040-1044 ◽  
Author(s):  
J. A. Mielczarski ◽  
M. Milosevic ◽  
S. L. Berets
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Constants ◽  
Infrared Region ◽  
Absorption Index ◽  
Reflection Spectra ◽  
Reflection Spectroscopy ◽  
Butyl Xanthate ◽  
Mid Infrared ◽  
Classical Oscillator

Reflection spectra of opaque samples recorded at different angles of incidence and for both polarizations were used to evaluate the optical constants. A subsequent classical oscillator fitting analysis of these spectra provided the dispersion of the refractive index and the absorption index for cuprous ethyl and butyl xanthate complexes across the mid-infrared region. The advantages of recording spectra under certain conditions are discussed.

Optical properties and limiting photocurrent of thin-film perovskite solar cells

2015 ◽  
Vol 8 (2) ◽  
pp. 602-609 ◽  
Author(s):  
James M. Ball ◽  
Samuel D. Stranks ◽  
Maximilian T. Hörantner ◽  
Sven Hüttner ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Solar Cells ◽  
Oblique Incidence ◽  
Optical Constants ◽  
Perovskite Solar Cells ◽  
Excellent Performance

Thorough measurements of the optical constants of CH3NH3PbI3are used to determine the limiting parasitic losses in solar cells revealing up to 100% IQE and excellent performance at oblique incidence.

scholarly journals Effect of Annealing on the Optical Properties of (PVA-CuCl) Composites

2016 ◽  
Vol 63 ◽  
pp. 98-105 ◽  
Author(s):  
Sabah A. Salman ◽  
Nabeel A. Bakr ◽  
Marwa R. Jwameer
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Optical Constants ◽  
Energy Gap ◽  
Copper Chloride ◽  
Chloride Salt ◽  
Casting Technique ◽  
Transmission And Absorption

Films of polymer (polyvinyl alcohol (PVA)) doped with CuCl salt at different concentrations (2 and 10) wt% were prepared using casting technique. The optical properties of the films were studied after annealing. The transmission and absorption spectra have been recorded in the wavelength range of (300-1100) nm. The effect of annealing on the optical properties for (PVA-CuCl) films with different concentrations (2 and 10) wt% of copper chloride salt shows that the transmittance decreased after annealing for all the films. The optical constants (absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant) for all the films are affected by annealing. The energy gap (Eg) of all the films decreased after annealing.

scholarly journals Natural Pigment –Poly Vinyl Alcohol Nano composites Thin Films for Solar Cell

2020 ◽  
Vol 17 (3) ◽  
pp. 0832
Author(s):  
Hanaa J. Alesa ◽  
Balqees M. Aldabbag ◽  
Rana M. Salih
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Contact Angle ◽  
Dielectric Constant ◽  
Optical Properties ◽  
Solar Cell ◽  
Melting Point ◽  
Polyvinyl Alcohol ◽  
Energy Gap ◽  
Natural Pigment

Solar cells thin films were prepared using polyvinyl alcohol (PVA) as a thin film, with extract of natural pigment from local flower. A concentration of 0.1g/ml of polyvinyl alcohol solution in water was prepared for four samples, with various concentrations of plant pigment (0, 15, 25 and 50) % added to each of the four solutions separately for preparing (PVA with low concentrated dye , PVA with medium concentrated dye and PVA with high concentrated dye ) thin films respectively . Ultraviolet absorption regions were obtained by computerized UV-Visible (CECIL 2700). Optical properties including (absorbance, reflectance, absorption coefficient, energy gap and dielectric constant) via UV- Vis were tested, too.  Fourier transform infrared (FTIR) spectrophotometer was employed to test the samples. Thermal analysis of thin films, including melting point (Tm), onset degree, endset degree, and crystallinity% were tested by differential scanning calorimeter (DSC). Three dimensional morphologies of thin films were inspected by atomic force microscopy (ATM). Contact angle also was tested as an index to hydrophilicity. Results proved that the ultraviolet and FTIR absorption increase after adding the natural pigment to PVA thin film, as well as it increases with increasing concentration of natural pigment. DSC analysis revealed an increase of PVA melting point when adding 15% concentration and it decreases with a 50% concentration of pigment. AFM results show an increase in surface roughness, hence the surface bearing index of PVA thin films is inversely proportional to pigment concentration. Contact angle decreases from 46.5° for pure PVA thin film to 44. 8°, 42. 6° and 35.2° after adding (15, 25, and 50)%  concentration of natural dye respectively. Optical properties were enhanced by adding the natural dye, hence energy gap decreased from 3 eV for pure PVA to 2.3 eV for the PVA with a high concentrate dye. Dielectric constant increased with increasing concentration of dye, which leads to high polarization of solar cell.                                                                        

scholarly journals Temperature-Dependent Optical Properties of Graphene on Si and SiO2/Si Substrates

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 358
Author(s):  
Sisi Wu ◽  
Lingyu Wan ◽  
Liangmin Wei ◽  
Devki N. Talwar ◽  
Kaiyan He ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Near Infrared ◽  
Infrared Region ◽  
Peak Position ◽  
Monolayer Graphene ◽  
Ultraviolet Region ◽  
Si Substrate ◽  
Temperature Dependent ◽  
Si Substrates

Systematic investigations are performed to understand the temperature-dependent optical properties of graphene on Si and SiO2/Si substrates by using a variable angle spectroscopic ellipsometry. The optical constants of graphene have revealed changes with the substrate and temperature. While the optical refractive index (n) of monolayer graphene on Si exhibited clear anomalous dispersions in the visible and near-infrared region (400–1200 nm), the modification is moderate for graphene on SiO2/Si substrate. Two graphene sheets have shown a pronounced absorption in the ultraviolet region with peak position related to the Van Hove singularity in the density of states. By increasing the temperature from 300 K to 500 K, for monolayer graphene on Si, the n value is gradually increased while k decreased. However, the optical constants [n, k] of monolayer graphene on SiO2/Si exhibited unpredictable wave variations. In the wavelength range of 400–1200 nm, an experiential formula of a like-Sellmeier equation is found well suited for describing the dispersions of graphene on Si and SiO2/Si substrates.

SYNTHESIS AND CHARACTERIZATION OF (ZNO)–(CO3O4) NANOCOMPOSITE VIA SPRAY PYROLYSIS PROCESS: THE USE OF THE BRUGGEMAN MODEL ON OPTICAL PROPERTIES PREVISION

2021 ◽  
pp. 2150066
Author(s):  
K. M. E. BOUREGUIG ◽  
H. TABET-DERRAZ ◽  
T. SEDDIK ◽  
M. A. BENALI
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Optical Properties ◽  
Band Gap ◽  
Spray Pyrolysis ◽  
Effective Dielectric Constant ◽  
Nanocomposite Thin Film ◽  
Bruggeman Model ◽  
Optical Dielectric Constant ◽  
Optical Dielectric

In the present paper, (ZnO)–(Co3O4) nanocomposite thin films have been prepared by using spray pyrolysis deposition on a glass substrate at 350∘C. After that, the as-obtained films have been characterized and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and the double beam UV-visible (UV-vis) spectrophotometer. Furthermore, the Bruggeman model is used to predict the evolution of the optical dielectric constant (real and imaginary parts: [Formula: see text] and [Formula: see text] to compare them with those obtained from the experimental results. The XRD pattern reveals that the nanocomposite film has diffraction peaks 2[Formula: see text], 36.95∘ corresponding respectively to the (220), (311) planes of cubic Co3O4 and another about of 2[Formula: see text] corresponding to the (101) plane of Wurtzite ZnO. Using the Debye Scherrer formula, the crystallite size of (ZnO)[Formula: see text]–(Co3O[Formula: see text] nanocomposite is found about 32[Formula: see text]nm, while the obtained thickness of this nanocomposite is about 780[Formula: see text]nm using the DekTak Stylus profilometer. Besides, the morphology analysis shows that the nanocomposite sample is well covered without holes and/or cracks and it has uniform dense grains. The evaluation of the transmittance, reflectance, refraction index, extinction coefficient, real and imaginary parts of dielectric constant as function of wavelength illustrates that the optical response of nanocomposite thin film (ZnO)[Formula: see text]–(Co3O[Formula: see text] depends on the influence of two mediums of pure materials ZnO and Co3O4 and their interaction. In addition, the direct band gap vs incident photon energy obtained from the Tauc plot equation shows that this nanocomposite has three values of band gap energy which are [Formula: see text][Formula: see text]eV, [Formula: see text][Formula: see text]eV (correspond to pure Co3O4 film) and [Formula: see text][Formula: see text]eV (correspond to pure ZnO film). Besides, the application of the Bruggeman equation indicates that the influence of the values of volume concentration and optical dielectric constant of the ingredient nanomaterials (ZnO and Co3O[Formula: see text] is significant on the value of the effective dielectric constant of nanocomposite thin film. The specific result of this study is the similarity between the spectra obtained from the Bruggeman model and the measured one, which proves that the application of this model is useful for the prediction of the optical properties of the composite.

scholarly journals Optical Properties of Perovskite Thin Film

2019 ◽  
Vol 30 (1) ◽  
pp. 174
Author(s):  
Bahjat B. Kadhim ◽  
Ali Zamil Manshad
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Constant ◽  
Optical Properties ◽  
Energy Gap ◽  
Refractive Indices ◽  
Ambient Conditions ◽  
Step Method ◽  
Solar Cell Application ◽  
Gap Energy

Methyl-ammonium lead tri iodide (CH3NH3PbI3) perovskite thin films have been prepared by solution processing. Thin film after deposited in the laboratory ambient conditions by drop casting, it prepared by two step method PbI2 and CH3NH3I at the glass substrate. The analysis provides: the absorption coefficient, extinction coefficient, refractive indices, real and imaginary components of the dielectric constant of the CH3 NH3 PbI3 films, energy gap. Energy gap of perovskite thin films is reached 1.8 that is very important for solar cell application.

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