The 2,4,5-Triphenyl Imidazole (TPI) C 21 H 16 N 2 samples were deposited as thin film by means of the physical vapor deposition (PVD) on glass and silicon substrates. As well as, three solutions with different concentrations using dimethyl sulfoxide (DMSO) solvent. The physical properties of all samples were investigated using different techniques. The thin film’s morphology was examined using atomic force microscopy (AFM) of the sample on silicon substrates, revealing a highly rough surface. The optical characteristics of both the thin film on glass substrate, the solutions, and the powder were studied through transmittance and absorbance measurements, which helped determine a value of the band gap of 3.45 eV. Photoluminescence and thermal photoluminescence spectroscopy showed the high emission of the material in its different aspects. Theoretical simulations of the HOMO–LUMO gap and electronic absorption spectra were obtained using the density functional theory (DFT) approach.

The paper presents research on the fabrication and electrical characterization of transparent contacts based on ZnO. Contact layers were manufactured in the process of physical vapor deposition (PVD) by the codeposition method, which allowed to obtain thin layers with various compositions and parameters. The evaporation unit NANO36 (Kurt&Lesker) allows real-time control of such parameters as the rate of layer growth, the composition of the obtained structure and its resultant thickness.The tests of the current-voltage characteristics were performed by typical source measure unit KEITHLEY 4200-scs system. Surface analysis was performed using an AFM microscope. The structures can be used in thin-film cells and are an alternative to ITO contacts.

2,3-Diphenyl Quinoxaline (DPQ) was deposited as a thin film using physical vapor deposition (PVD) on glass and silicon substrates, and its physical properties were thoroughly examined using various techniques. Atomic force microscopy (AFM) analysis revealed a highly rough surface morphology. Optical properties were assessed through transmittance and absorbance measurements, aiding in determining the band gap energy at 3.34 eV. Photoluminescence (PL) and thermal photoluminescence spectroscopy highlighted the material’s strong emission, with decay time confirming its fluorescence nature. Current-voltage characteristics were studied through implementation in a p-n junction, showcasing DPQ’s suitability as both an electron and hole transporting layer in optoelectronic devices.

In the present work, the second- and third-order nonlinear optical (NLO) properties of composite materials based on Europium (Eu) and Gadolinium (Gd) complexes and poly (methyl methacrylate) (PMMA) in thin film form were investigated. The thin films were prepared by using the spin coating technique. The Maker fringe technique was used to study the second and third harmonic generation (SHG and THG) in the picosecond regime at the incident wavelength of 1064 nm. After applying the corona poling approach, the second-order nonlinear susceptibility χ (2) and third-order nonlinear susceptibility χ (3) were estimated using the comparative models of Lee and Kubodera-Kobayashi, respectively. These compounds have good nonlinear properties, according to the data, which makes them a viable candidate for optoelectronic applications.

This work falls into the theme of studying energy efficient organic Light Emitting Diodes (organic LEDs) by relying on optical techniques. Our aim is to take a deeper look into the emission in the near infrared region after visible excitation, of copper phthalocyanine thin film deposited on glass by physical vapor deposition, using photoluminescence spectroscopy (PL), in order to use the latter as a hole injection layer or emissive layer in organic LEDs and consequently to enhance its efficiency.

In this paper, a comparative study of the maximum power on the shading rate on the maximum power of thin film PV modules. Thus two thin film PV modules of type Copper indium gallium selenide, CIGS, of 90W power and a CdTe (Cadmium telluride)/CdS (Cadmium sulfide) module, of maximum power 75 W. These modules, reference SN-CIGS90 and CX3 75 were tested under the conditions of the installation site to ensure their proper functioning and to determine the initial values of electrical parameters before shading. The results obtained are as follows: for the CIGS: Pm (80.717 W); Vco (23.06 V), Icc (3.5 A) and for the CdTe:Pm (54.914 W); Vco (35.52 V), Icc (1.546 A). After this characterization test, the modules are exposed to real operating conditions at the Center for Study and Research on the renewable energy (CERER), Cheikh Anta Diop University in Dakar. Four types of shading are performed on each module with the same mask: partial shading at 25%, 50%, 75% and complete shading at 100%. The comparison of the variation rates obtained on the experimental values of the 4 types of shading carried out on each module, shows that, the phenomenon of shading constitutes an environmental factor which influences negatively the maximum power of the thin film PV modules. But this reduction depends on the surface of the shaded module, the nature of the mask but also the technology used. Indeed, for a shading of 25% of the surface of the two modules, we note a reduction of 21.32% of power for the CIGS, against 40.53% for the CdTe/CdS, that is to say a difference which approaches 20%.

Transparent conductive thin films based on Tin (Sn) doped zinc oxide (TZO) were prepared using the chemical spray pyrolysis technique. The crystalline structure, strain, stress, roughness characteristics, electrical and nonlinear optical susceptibility of TZO were studied The films have been investigated using x-ray diffraction, atomic force microscopy (AFM), electrical resistivity, and third harmonic generation (THG) techniques. The greatest value of the susceptibility chi((3)) was about 10.91x10(-12)(esu) obtained from the 2% doped films, which have less roughness and the low electrical resistivity of 5x10(-2) Omega cm. Moreover, third order non-linear optical susceptibilities were of the order of 10(-12) (esu), higher than that of the undoped ZnO.

The spectral mismatch between solar cells and incident radiation is a fundamental factor limiting their efficiencies.There are materials and luminescent processes which can modify the incident sunlight's properties to better suit the cell's optimal absorption regions.Developing new structures or optical devices to improve the trapping of light within solar cells is a real challenge.This work is part of the theme of increasing the efficiency of solar cells by relying on techniques offered by optical engineering.Our aim is to study the visible photoluminescence spectra after Ultraviolet (UV) excitation, of hafnium and erbium codoped zinc oxide, in order to modify the solar spectrum and adapt it to the solar cell, and consequently to enhance its efficiency.In addition we will study the use of these films as photovoltaic anode.

The aim of this article is to study the effects of the shading rate on the electrical performance parameters of CIGS PV modules. The study concerns a new flexible CIGS type photovoltaic module with a power of 90 W, manufactured by the company Shenzhen Shine Solar Co., Ltd. This module, reference SN-CIGS90, is tested under the initial conditions to ensure its correct operation and to determine the initial values of the electrical parameters before shading. After this characterization test, the module is exposed under the actual operating conditions of the Renewable Energies Study and Research Center (CERER), located in Dakar, then 4 types of shading are performed with the same mask: partial shading 25% partial shading, 50% partial shading, 75% partial shading, and 100% full shading. The variation rates obtained on the experimental values of the 4 types of shading carried out determine that the shading phenomenon constitutes a factor that influences negatively on the electrical parameters of a CIGS-based PV module. Indeed, for 25% of the surface of the shaded module, there is a reduction of 58.139% of the maximum power and of 60.507% of the efficiency and for shading of 100%, the module loses 84.436% of its maximum power and 84.135% of its performance.

The aim of this work is to measure the photoluminescence of the Disperse Blue 79 (DB 79) deposited as thin films and study its morphological properties by the mean of the Atomic Force Microscopy technique in order to apply it as an Organic Emitting Light Diode (OLED). The films were prepared by the mean of the home-made Physical Vapor Deposition apparatus in a high vacuum on BK7 glass substrates. The linear optical properties were studied by photoluminescence and decay time spectra. The photoluminescence was measured in a broad ranged from 25 to 300 K in a high vacuum, while the decay time technique was investigated to measure the studied sample’s life-time in real time. Obtained results confirm homogeneous morphology and good optical quality of investigated organic azobenzene dye. These results allow the DB 79 dye to be used for the first time in production of the Organic Light Emitting Diodes (OLEDs).

Li and Sn codoped ZnO (LTZO) thin films have been successfully deposited on heated glass substrates at 450 degrees C using the spray pyrolysis technique, the effect of lithium of Sn-doped zinc oxide on the structural, morphological, optical and nonlinear optical properties was investigated using X-ray diffraction, transmission, the RMS average surface roughness, and third harmonic generation (THG). The value of optical band gap Eg was found to be decreased from 3.24 eV to 3.16 eV when the concentration of Li from 0 to 7%, while the concentration of Sn is fixed at 2%. The doping of ZnO films improves the nonlinear response and the highest susceptibility value chi((3)) = 13.422 x 10(-12) (esu) is found at concentration of lithium 7%.

The third order nonlinear optical properties were reported for a new synthesized molecules based on triazepine and thianine, using the third harmonic generation (THG) technique. After synthesis, the powders were deposited on glass substrates using dip coating technique in order get thin films. These thin films were characterized, by different techniques, we mention the absorption and X-ray diffraction. The measurements of third order nonlinear optical susceptibilities were performed on these thin films, using the THG technique at 1064 nm. These investigations were completed by theoretical studies, using energy levels theory HOMO–LUMO and the second order hyperpolarizabilities (γ) results. Good agreement was obtained between the theoretical and experimental results.

Thin polymer films are currently under intensive investigation owing to their promising optical and electrical properties. The roughness and refractive index variation in a film, and also presence of unwanted molecular inclusions in bulk created during film formation may lead to incoherent light scattering. Therefore the analysis of thin film optical spectra becomes more complicated. The aim of this work is presentation of light scattering phenomena occurring in a polymer layer. The phenomena can be described by the Fresnel model for specular reflectance and also Rayleigh, Debye and scalar theories of light scattering for non-directional reflection from a diffusive film. Furthermore, the optical methods based on combined spectro-goniometric measurements have been presented. These investigations allow determining many important parameters such as optical constants, films thickness and their surface roughness and also optical scattering coefficients of diffusive layers.

Li and Sn codoped ZnO (LTZO) thin films have been prepared by spray pyrolysis technique and their structural, morphological properties have been investigated. The films were characterized by Xray diffractometer (XRD), Scanning electron microscopy (SEM) and atomic force microcopy (AFM). XRD results revealed that all thin films (LTZO) are polycrystalline with à hexagonal wurtzite structure, the crystalline structures of the films showed depending on the increasing of lithium content. The (SEM) images showed that the LTZO thin films were changed with Li incorporation, the wrinkle structure disappeared with increasing Li content. It is remarqued that the surface is uniform with same clusters of irregularly shaped grain distributed at Li content at 7%. The AFM images of LTZO thin films decreased from 26.95 nm to 13.678 nm with the increase of Li concentration from 0% to 7% fixed Sn concentration of 2%.

In this talk, after a short introduction on the methodologies used for computing dipole polarizability (alpha), second and third-order hyperpolarizability and susceptibility; the results of theoretical studies performed on density functional theory (DFT) and ab-initio quantum mechanical calculations of nonlinear optical (NLO) properties for a few selected organic compounds and polymers will be explained. The electric dipole moments (mu) and dispersion-free first hyperpolarizabilities (beta) for a family of azo-azulenes and a styrylquinolinium dye have been determined by DFT at B3LYP level. To reveal the frequency dependent NLO behavior, the dynamic a, second hyperpolarizabilities (gamma), second (chi((2))) and third-order (chi((3))) susceptibilites have been evaluated using time-dependent HartreeFock (TDHF) procedure. To provide an insight into the third-order NLO phenomena of a series of pyrrolo-tetrathiafulvalene-based molecules and pushpull azobenzene polymers, two-photon absorption (TPA) characterizations have been also investigated by means of TDHF. All computed results of the examined compounds are compared with their previous experimental findings and the measured data for similar structures in the literature. The one-photon absorption (OPA) characterizations of the title molecules have been theoretically obtained by configuration interaction (CI) method. The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps have been revealed by DFT at B3LYP level for azo-azulenes, styrylquinolinium dye, push-pull azobenzene polymers and by parametrization method 6 (PM6) for pyrrolo-tetrathiafulvalene-based molecules. (C) 2016 Elsevier B.V. All rights reserved.

Tin-doped indium oxide (In 2 O 3 :Sn) thin films in different concentrations (Sn = 0, 3, 5, 8 at.%) were deposited by reactive chemical pulverisation spray pyrolysis on heated glass substrates at 500 °C. The effect of the tin dopant on the nonlinear optical properties was investigated using X-ray diffraction, transmission, electrical resistivity and third harmonic generation (THG). All films were polycrystalline, and crystallised in a cubic structure with a preferential orientation along the (400) direction. The Sn (5 at.%) doped In 2 O 3 thin films exhibited a lower resistivity of 3 × 10 -4 Ω cm, and higher transmission in the visible region of about 94%. Optical parameters, such as the extinction coefficient ( k ), refractive index ( n ) and energy band gap ( E g ), were also studied to show the composition-dependence of tin-doped indium oxide films. The nonlinear properties of the In 2 O 3 :Sn thin films have been found to be influenced by doping concentration, and the best value of χ (3) = 3 × 10 -11 (esu) was found for the 5 at.% doped sample.

This paper explores the synthesis, structure characterization and optical properties of two new schiff bases. These compounds were obtained by condensation of o-tolidine with salicylaldehyde and cinnamaldehyde. The obtained ligands were characterized by UV, H-1 and NMR. Their third-order NLO properties were measured using the third harmonic generation technique on thin films at 1064 nm. The electric dipole moment (mu), the polarizability (alpha) and the first hyperpolarizability (beta) were calculated using the density functional B3LYP method with the lanl2dz basis set. For the results, the title compound shows nonzero beta value revealing second order NLO behaviour. (C) 2015 Elsevier B.V. All rights reserved.

The purpose of our study is to find a suitable material to be used in spintronic applications and to find the relation between the parameters of deposition by spray pyrolysis technic (temperature, concentration of Ni doping) and the ferromagnetic properties (Curie temperature, magnetic moment). The nickel-doped zinc oxide, Zn.1− x .Ni x O ( x = 0.01, 0.03, 0.05), and diluted magnetic semiconductors (DMSs) are synthesized by the spray pyrolysis technic. The results of The X-ray diffraction (XRD) of prepared substrates confirm the incorporation of the dopants into the ZnO lattice structure. The spin-polarized electronic properties has been found and was investigated in detail by using the density-functional theory (DFT), the local density approximation (LDA), and The Korringa–Kohn–Rostoker coherent potential approximation (KKR-CPA). As result, nickel doping brings up a half-metallic appearance due to the hybridization between the 3d state of Nickel impurities and the oxygen 2p state. The mechanism of the interatomic exchange has been explained as being a p-d double exchange.

Transparent conducting ZnO doped Bi thin films were prepared on glass substrates by ultrasonic spray method. The influence of Bi doping concentration on the structural, optical and nonlinear optical properties of ZnO thin films was studied. The X-ray diffraction (XRD) analysis show that all studied films have a hexagonal wurtzite structure and are preferentially oriented along the c-axis from substrate surface. Optical transmittance measurements show that all samples have average 80% transparency in the visible light. Optical band gap values range between 3.14 and 3.28 eV. ZnO film with 3 wt% of Bi showed the highest electrical conductivity. In addition, the second and third order nonlinear susceptibilities were determined and their values have been calculated. (C) 2015 Elsevier Ltd. All rights reserved.

Nanocrystalline Fluorine-doped indium oxide (IFO) thin films have been deposited with various substrate temperatures by reactive chemical pulverization spray pyrolysis technique onto glass substrates. The effect of substrate temperature (Ts) on the stress and luminescence properties was investigated in detail using X-ray diffraction, transmission, photoluminescence spectroscopy, electrical resistivity and scanning electron microscopy (SEM). XRD analysis confirmed the cubic structure of polycrystalline In 2 O 3 . The preferred growth orientation along (222) plane shifts to (400) and the compressive stress decreases from 1.20 to 0.11 GPa when the substrate temperature was increased from 400 to 500 °C. The photoluminescence (PL) spectra of (IFO) present two blue and a yellow emission. Intensive blue PL bands at 414 and 436 nm were observed in the samples deposited at 500°C, which present the strongest orientation along (400) peak and a lower resistivity of 1.4 × 10 -2 Q cm. A shift of blue peaks to shorter wavelength of (IFO) films has also been observed with the increase of Ts and this may be attributed to the change of stress present in the films.