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Structural, optical, optoelectrical and photovoltaic properties of the thermally evaporated Sb2Se3 thin films
摘要： Production of inexpensive and promising light-absorbing materials is very important in photovoltaic device applications. In this study, we investigate the preparation of good-quality antimony selenide (Sb2Se3) thin films via thermal evaporation procedure with different thicknesses (241, 315, 387 and 429 nm). The analysis of the X-ray diffraction examination of the Sb2Se3 thin films demonstrates that the as-deposited Sb2Se3 thin films are polycrystalline with a single-phase orthorhombic structure. The elemental composition analysis of the evaporated Sb2Se3 thin film established that the as-deposited film has near stoichiometric composition of the compound. The linear optical results of the Sb2Se3 thin films revealed that the films show optical direct transitions and optical energy gaps in the range 1.12–1.05. The optoelectrical parameters of the Sb2Se3 thin films (ratio of the charge carrier concentrations to the effective mass N/m*, optical electronegativity ξopt and the lattice dielectric constant, εL) were estimated. The analysis of nonlinear optical parameters of the Sb2Se3 thin films reveals the increase of the film thickness combined with increase in the nonlinear refractive index. The Al/n-Si/Sb2Se3/Ag heterojunction was produced by the thermal evaporation technique. The photovoltaic constants of the Al/n-Si/Sb2Se3/Ag heterojunction were estimated from the J–V curve and demonstrate a solar efficiency of 4.03%.
关键词： Structural properties,Optoelectrical properties,Photovoltaic properties,Sb2Se3 thin films,Optical properties,Thermal evaporation
更新于2025-09-12 10:27:22
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Influence of cadmium precursor concentrations on the structural, optical and electrochemical impedance properties of CdZnS thin films
摘要： Thin films of cadmium zinc sulfide (CdZnS) were deposited on microscopic glass substrates using the chemical bath deposition method and the effects of the Cd precursor concentrations on the morphological, structural and optical properties of the films were studied. The surface morphology as revealed by scanning electron microscope showed closely packed nano particles randomly spread on the surface of the glass substrates. The x-ray diffraction studies showed that the thin films were polycrystalline and the crystallite size decreased with increase in the concentration of the Cd precursor. While the optical absorbance decreased, the bandgap energy increased as the concentration of the cadmium source increased. Electrochemical studies were performed by cyclic voltammetry analysis and impedance measurements at low frequency ranges. Simulation model on the impedance model was carried out to obtain a more quantitative analysis of the data. The ternary CdZnS thin film developed in this work could be useful as window layer in solar cell fabrication.
关键词： electrochemical impedance properties,optical properties,chemical bath deposition,structural properties,CdZnS thin films,cadmium precursor concentrations
更新于2025-09-11 14:15:04
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The effects of gadolinium doping on the structural, morphological, optical, and photoluminescence properties of zinc oxide nanoparticles prepared by co-precipitation method
摘要： Pure and gadolinium (Gd)-doped zinc oxide (ZnO) nanoparticles were prepared by co-precipitation method. The EDS analysis confirmed the presence of Gd3+ ions in ZnO lattice. The X-ray diffraction measurement indicated the formation of hexagonal wurtzite structure for both pure and Gd-doped ZnO nanoparticles. The structural parameters of nanoparticles such as lattice constant, crystallite size, dislocation density, micro strain and other lattice parameters were calculated from XRD data. FESEM images of nanoparticles showed that the grain morphology of nanoparticles tends to hexagonal form by introducing Gd3+ ions into the ZnO lattice. The presence of functional groups and chemical bonding attributed to ZnO was confirmed by FT-IR measurement. The optical properties of nanoparticles were investigated by UV–Vis spectroscopy. The UV–Vis absorbance spectra, for Gd-doped samples, illustrated a blue shift by increasing Gd concentration. Also, the band gap of nanoparticles increased by increasing Gd concentration. The photoluminescence spectra of Gd-doped nanoparticles showed that the intensity of green luminescence increases by substitution of Gd3+ ions into the ZnO lattice attributed to the oxygen vacancies.
关键词： structural properties,morphological properties,co-precipitation method,gadolinium doping,zinc oxide nanoparticles,optical properties,photoluminescence properties
更新于2025-09-10 09:29:36
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Studies on structural, optical and magnetic properties of (Ru, Mn) codoped ZnO nanostructures
摘要： Ruthenium and manganese codoped ZnO (RuxMn0.01Zn0.99-xO; x = 0.01, 0.02 and 0.03) were synthesized by sol-gel method via ultrasonication. The effects of codoping on structural, microstructural, optical and magnetic properties of the as-synthesized materials were characterized through X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL) and SQUID magnetometer, respectively. From the XRD pattern, it is evident that all the diffraction peaks can be indexed to the hexagonal wurtzite structure and shows the incorporation of dopants ie. Ru and Mn are substituted in the ZnO lattice. Nanosphere like morphology was observed in HRTEM analysis and the average particle sizes are found to be 20-30 nm, which are good agreement with the XRD crystallite size by Scherrer formula. Photoluminescence (PL) studies were carried out to investigate the optical properties of the as-synthesized materials and the defects related strong green emission peaks was observed in the TM codoped ZnO samples. It can be clearly seen from SQUID results, the loop is linear with the field indicating the presence of paramagnetism / anti ferromagnetism in the samples.
关键词： ZnO,sol-gel,optical properties,codoping,ultrasonication,magnetic properties,structural properties
更新于2025-09-10 09:29:36
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Computational Chemistry Meets Experiments for Explaining the Geometry, Electronic Structure, and Optical Properties of Ca <sub/>10</sub> V <sub/>6</sub> O <sub/>25</sub>
摘要： In this paper, we present a combined experimental and theoretical study to disclose, for the first time, the structural, electronic, and optical properties of Ca10V6O25 crystals. The microwave-assisted hydrothermal (MAH) method has been employed to synthesize these crystals with different morphologies, within a short reaction time at 120 °C. First-principle quantum mechanical calculations have been performed at the density functional theory level to obtain the geometry and electronic properties of Ca10V6O25 crystal in the fundamental and excited electronic states (singlet and triplet). These results, combined with the measurements of X-ray diffraction (XRD) and Rietveld refinements, confirm that the building blocks lattice of the Ca10V6O25 crystals consist of three types of distorted 6-fold coordination [CaO6] clusters: octahedral, prism and pentagonal pyramidal, and distorted tetrahedral [VO4] clusters. Theoretical and experimental results on the structure and vibrational frequencies are in agreement. Thus, it was possible to assign the Raman modes for the Ca10V6O25 superstructure, which will allow us to show the structure of the unit cell of the material, as well as the coordination of the Ca and V atoms. This also allowed us to understand the charge transfer process that happens in the singlet state (s) and the excited states, singlet (s*) and triplet (t*), generating the photoluminescence emissions of the Ca10V6O25 crystals.
关键词： structural properties,electronic properties,Ca10V6O25,microwave-assisted hydrothermal method,photoluminescence,optical properties
更新于2025-09-10 09:29:36
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Substrate temperature-dependent properties of sprayed cobalt oxide thin films
摘要： Cobalt oxide (Co3O4) thin films were deposited onto amorphous glass substrates using a home-made pneumatic spray pyrolysis system (SPT) from aqueous solution of cobalt chloride salt (CoCl2) as a source of cobalt. The films were deposited at different substrate temperatures ranging from 250 to 450?°C in steps of 50?°C. The effect of substrate temperature on structural, electrical and optical properties was studied. The characterization of samples was carried out by X-ray diffraction (XRD), UV–Vis spectroscopy, energy dispersive spectroscopy (EDS), scanning electron microscopy and four probe points measurements. The XRD study showed that all the films were polycrystalline consisting of Co3O4 spinel cubic phase. The preferred orientation of the crystallites changed from (311) to (111) when the substrate temperature increases. The average calculated grain size was about 40.38?nm. Morphological studies exposed that the films surface morphology is almost homogeneous and well-covered. Peaks associated with Co and O elements are present in EDS analysis witch confirm the composition of the films. The optical transmittance and the band gaps energy increase with the increase of substrate temperature. The measured electrical conductivity at room temperature was found in the order of 10?1 (??cm)?1.
关键词： Thin films,Substrate temperature,Cobalt oxide,Spray pyrolysis,Structural properties,Optical properties,Electrical properties
更新于2025-09-10 09:29:36
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Graphene oxide model with desirable structural and chemical properties
摘要： Due to unique chemical, electrical and optical properties, graphene oxide has been widely used as a promising candidate for many applications. Theoretical GO models developed so far present a good description of its chemical structure. However, when it comes to the structural properties, such as the size and distribution of vacancy defects, the curvature (or roughness), there exist significant gaps between computational models and experimentally synthesized GO materials. In this work, we carry out reactive molecular dynamics simulations and use experimental characteristics to fine tune theoretical GO models. Attentions have been paid to the vacancy defects, the distribution and hybridization of carbon atoms, and the overall C/O ratio of GO. The GO models proposed in this work have been significantly improved to represent quantitative structural details of GO materials synthesized via the modified Hummers method. The temperature-programmed protocol and the computational post analyses of Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, vacancy size and curvature distribution, are of general interest to a broad audience working on GO structures from other synthesis methods and other two-dimensional materials and their composites.
关键词： Chemical properties,Reactive molecular dynamics,Modified Hummers method,Graphene oxide,Structural properties
更新于2025-09-10 09:29:36
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GROWTH CHARACTERISTIC OF GZO FILM FABRICATED BY RF MAGNETRON SPUTTERING
摘要： This paper investigate the dependence of film thickness onto characteristic of Gallium doped Zinc Oxide (GZO). GZO films were deposited on a glass substrate by RF Magnetron Sputtering using GZO ceramic target with 99.99% purity. Thicknesses were altered by varying the deposition time from 10 min to 50 min meanwhile the sputtering power, argon flow and target distance were fixed in order to investigate the influence of film thickness to the growth characteristic, structural, optical properties and surface morphology of the films. Sputtering was performed with RF power of 100 watt and the argon flow was set at 10 sccm. GZO thin films on various thicknesses range from 130 nm to 460 nm were successfully deposited onto glass substrate with the crystallite grain size in range of 20.63 nm to 22.04 nm with the optical transmittance above 85 %.
关键词： RF sputtering,growth characteristic,GZO,optical properties,surface morphology,structural properties
更新于2025-09-10 09:29:36
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Thermal annealing induced evolution of AgIn5Se8 phase from Ag/In2Se3 bilayer thin film
摘要： In the present report, we have investigated the AgIn5Se8 phase formation upon annealing the Ag/In2Se3 bilayer film prepared by the thermal evaporation technique. The optical, morphology as well as structural parameters was tuned with different annealing temperature. The prominent crystalline phase developed at 2500C annealing where as there is no signal of this phase in the as-prepared film (amorphous). The analysis using XRD study showed the amorphous to crystalline phase transformation with annealing. The indirect as well as the direct band gap is found to be increased with annealing (up to 1500C) and then decreased due to the growing up new phase as explained by phase transformation and decrease in density of localized states. The formation of dangling bonds at the surface near the crystallite sites during crystallization process reduces the band gap. The Tauc parameter change shows the degree of chemical disorderness in the films. The transmitivity, absorption coefficient, oscillator energy, refractive index, dispersion energy and extinction coefficient are found to be changed accordingly with annealing condition.The micro structural study done by Scanning Electron Microscopyshows the formation of crystallites upon annealing. The Raman study of these films supports the formation of new phase.
关键词： bandgap,Thin films,annealing,optical properties,chalcopyrite,structural properties
更新于2025-09-10 09:29:36
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Tailoring the Structural and Optical Parameters of Eu3+:CeO2-SiO2 Nanopowder Via Thermal Treatment
摘要： Nanocrystalline Eu3+:CeO2-SiO2 powder samples were prepared by sol-gel technique. This technique is suitable for large-scale production and it is also a cost effective process. The prepared samples were annealed at different temperatures which were characterized by many complementary techniques. The formation of cubic fluorite structure of CeO2 nanocrystal with a uniform distribution was confirmed by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The average nanocrystalline size has been calculated as 3, 7 and 15 nm using Debye-Scherrer formula for different annealed samples. The calculated nanocrystalline sizes were compared with W-H plot and TEM histograms. It was investigated that FWHM of diffraction peaks decreases with increase in temperature results in increase nanocrystalline size. The FTIR spectroscopy provides the valuable information and identification of different chemical group/bonds present in the prepared samples. It is found that if we fixed the dopant concentration, then particle size, morphology and band gap energy of prepared nanopowder can be tailored by applying the annealing conditions. Comparative studies of absorption spectra and corresponding band gap energies have been done and a red shift has been observed in absorption spectra with thermal treatment. The shift of the optical absorption edge of prepared nanopowder towards lower energies increases its utilization in the visible region specially photocatalytic activity.
关键词： Thermal annealing,Absorption spectra,Structural properties,Nanopowder,Band gap energy
更新于2025-09-10 09:29:36