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Structural and optical studies on PVA capped SnS films grown by chemical bath deposition for solar cell application
摘要： Tin monosulphide (SnS) thin films capped by PVA have been successfully deposited on glass substrates for cost effective photovoltaic device applications by a simple and low-cost wet chemical process, chemical bath deposition (CBD) at different bath temperatures varying in the range, 50–80 °C. X–ray diffraction analysis showed that the deposited films were polycrystalline in nature, showing orthorhombic structure with an intense peak corresponding to (040) plane of SnS. These observations were further confirmed by Raman analysis. FTIR spectra showed the absorption bands which corresponds to PVA in addition to SnS. The scanning electron microscopy and atomic force microscopy studies revealed that the deposited SnS films were uniform and nanostructured with an average particle size of 4.9 to 7.6 nm. The optical investigations showed that the layers were highly absorbing with the optical absorption coefficient ~105 cm–1. A decrease in optical band gap from 1.92 to 1.55 eV with an increase of bath temperature was observed. The observed band gap values were higher than the bulk value of 1.3 eV, which might be due to quantum confinement effect. The optical band gap values were also used to calculate particle size and the results are discussed.
关键词： structural properties,optical properties,SnS thin films,polyvinyl alcohol,capping agent,chemical bath deposition
更新于2025-11-21 11:18:25
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Effect of rare earth Pr doping on core characteristics of electrodeposited nanocrystalline Cu2O films: a film for optoelectronic technology
摘要： Undoped and Pr doped Cu2O nanocrystalline ?lms were fabricated by the electrodeposition method. These ?lms were studied to investigate the formation, morphology, optical, and photoresponse properties on Pr doping concentrations (i.e., 0, 1, 3, and 5 wt%). Structural studies of the deposited Cu2O:Pr ?lms exposed the cubic crystal structure with polycrystalline nature. The crystallite size is decreased from 54 to 29 nm by increasing the Pr doping concentrations. The Raman peaks at 110, 147, 215, 413, and 633 con?rm the Cu2O phase and well matched with the XRD results. The morphological study shows that the pyramid-shaped particles are homogeneously arranged on the ?lm surfaces. The absorption is high for the ?lm deposited with the 5% Pr doping is due to the maximum thickness than the other ?lms. The calculated band gap values of Cu2O:Pr ?lms were reduced from 2.06 to 1.90 eV with raising the Pr doping level. PL spectra showed high intense emission peak at 617 nm which con?rms the NBE emission of Cu2O lattice. Index of refraction (n) and coef?cient of extinction (k) values were increased on increasing the doping concentration from 0 to 5%. From photosensitivity analysis, there is an increase of photoresponse behavior with respect to illuminated current.
关键词： Electrodeposition,Structural,Optical and electrical properties,Morphological
更新于2025-11-21 11:18:25
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Color Reproduction Accuracy Promotion of 3D-Printed Surfaces Based on Microscopic Image Analysis
摘要： Full-color 3D printing technology is a powerful process to manufacture intelligent customized colorful objects with improved surface qualities; however, poor surface color optimization methods are the main impeding factors for its commercialization. As such, the paper explored the correlation between microstructure and color reproduction, then an assessment and prediction method of color optimization based on microscopic image analysis was proposed. The experimental models were divided into 24-color plates and 4-color cubes printed by ProJet 860 3D printer, then impregnated according to preset parameters, at last measured by a spectrophotometer and observed using both a digital microscope and a scanning electron microscope. The results revealed that the samples manifested higher saturation and smaller chromatic aberration (ΔE) after post-processing. Moreover, the brightness of the same color surface increased with the increasing soaked surface roughness. Further, reduction in surface roughness, impregnation into surface pores, and enhancement of coating transparency effectively improved the accuracy of color reproduction, which could be verified by the measured values. Finally, the chromatic aberration caused by positioning errors on different faces of the samples was optimized, and the value of ΔE for a black cube was reduced from 8.12 to 0.82, which is undetectable to human eyes.
关键词： Structural characterisation,Impregnating process,Scanning electron microscope,Image analysis,Color optimization,Full-color printing
更新于2025-11-21 11:18:25
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White light emitting thermally stable bismuth phosphate phosphor Ca <sub/>3</sub> Bi( <scp>PO</scp><sub/>4</sub> ) <sub/>3</sub> :Dy <sup>3+</sup> for solid state lighting applications
摘要： White light emitting dysprosium doped Ca3Bi(PO4)3 phosphor was successfully synthesized via co-precipitation method for the first time and the structural, vibrational, morphological and luminescent properties have been investigated for solid state lighting applications. The X-ray diffraction (XRD) and structural refinement studies reveal that the synthesized phosphors consist of single phase with cubic structure. The field emission scanning electron microscopy (FE-SEM) images reveal that the as-synthesized phosphor has micron size with an irregular shape. Under near ultraviolet (n-UV) and blue excitation, the phosphor exhibits white light emission via a combination of blue (~451 nm) and yellow (~575 nm) emission bands. The optimized concentration of Dy3+ ions is 6.0 mol % after which the concertation quenching takes place. The process of energy transfer between Dy3+ ions is due to dipole-dipole interaction, which was confirmed by applying Dexter and Reisfeld’s Energy Transfer (ET) formula. The CIE chromaticity coordinates for the optimized phosphor were (0.329, 0.377), which lie in the white light region. The emission intensity remains to 83.41% at 373 K to that of at room temperature, which indicates good thermal stability. The above mentioned results demonstrate that Ca3Bi(PO4)3 is a potential phosphor for solid state lighting applications.
关键词： White LEDs,Structural and luminescent properties,White light emission,Phosphor,Thermally stable
更新于2025-11-21 11:18:25
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Molten salt synthesis of highly ordered and nanostructured hexagonal boron nitride
摘要： Hexagonal boron nitride (h-BN) is a well-known ceramic that has wide application areas ranging from electronics to metallurgy. However, highly ordered h-BN is conventionally synthesized at high temperatures above 1800 °C. In this work, we investigated the formation of BN from boric acid (H3BO3)-ammonium chloride (NH4Cl) mixture in the sodium chloride (NaCl)-potassium chloride (KCl) eutectic salt. We report the synthesis of highly ordered and nanostructured h-BN at 1000 °C using molten salt synthesis. The effect of starting composition, synthesis temperature, and dwell time on BN formation and its structural ordering were systematically investigated. It is concluded that the molten salt plays important roles in the formation of BN and its structural ordering, which is achieved by i) decomposing the boron (B)-nitrogen (N) bearing reactants that lead to the formation of BN layers, and ii) increasing the mobility of BN layers formed. Furthermore, we propose a possible reaction mechanism that governs the BN formation from the reactant mixture in molten salts and explain the observations based on thermodynamic and kinetic considerations.
关键词： Molten salt synthesis,NaCl-KCl eutectic salt,Boron nitride,Structural ordering,High-resolution transmission electron microscopy
更新于2025-11-21 11:01:37
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Effect of electron beam irradiation on structure, morphology, and optical properties of PVDF-HFP/PEO blend polymer electrolyte films
摘要： The effect of 8 MeV energy electron beam (EB) on poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/poly-ethylene oxide (PEO) (@ w/w 90:10, PHP10) polymer blend films have been prepared and studied. The change in structure, morphology, and optical properties at 40, 80, and 120 kGy EB doses were investigated. The effect of the radiation process may responsible to occurs the degradation (chain scission) and chain link (cross linking) which are confirmed by the FT-IR analysis. The band at 1401 cm?1 corresponding to the –CH2– bending or scission mode have shifted to 1397 cm?1 after 120 kGy EB dose is due to the intermolecular interaction and the changes of the macromolecular chain by breaking of bonds with increased EB dose was observed. The XRD pattern shows decreased in the crystallinity from 60.03 to 23.42% and increased amorphousity for 120 kGy EB dose the and the surface morphology was drastically changed by decreasing the size of spherulites upon increased EB dose. The increase in optical absorption and the shifting of wavelength toward a higher end (red shift) was observed after the irradiation. The energy band gaps (Eg), and Urbach energy were estimated and they are found to be decreased, but the number of carbon atoms in a cluster of was increased with increased EB dose. The obtained results notice that the physical properties of polymer blend electrolytes can be improved by EB irradiation to use in different potential applications.
关键词： Polymer electrolyte,FESEM,UV–visible spectroscopy,Structural analysis,Electron beam irradiation
更新于2025-11-21 11:01:37
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Cu nanoclusters in ion exchanged soda-lime glass: Study of SPR and nonlinear optical behavior for photonics
摘要： Nanomaterials with large optical nonlinearities have received considerable attention in the field of modern science and nanotechnology. In this paper, we have studied nonlinear optical and surface plasmon resonance properties and behavior of Cu nanoclusters formed in ion exchanged soda-lime glass. The soda-lime glasses were successfully doped with Cu nanoclusters in the ion-exchange process. The size of the clusters estimated from the optical absorption spectroscopy results closely matched with those obtained from the transmission electron microscopy data. The results revealed that spherical shaped Cu nanoclusters were homogeneously distributed in the glass matrix and the size of the Cu nanoclusters varied from 4 to 10 nm. The structure and chemical state were further analyzed by X-ray diffraction and X-ray photoelectron spectroscopy. The nonlinear optical behavior of the materials was analyzed using femtosecond Z-scan technique. The nonlinear refraction index (n2), nonlinear absorption coefficient (β) and the third-order nonlinear optical susceptibility (χ(3)) were estimated to be -1.72 × 10?17 m2/W, 9.96 × 10?11 m/W, and 0.56 × 10?11 esu, respectively, which shows possible application in the field of photonics.
关键词： Surface plasmon resonance,Z-scan technique,Metal forming and shaping,Structural,Nanoparticles
更新于2025-11-20 15:33:11
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Laser-driven structural transformations in dextran- <i>graft</i> -PNIPAM copolymer/Au nanoparticles hybrid nanosystem: the role of plasmon heating and attractive optical forces
摘要： Laser induced structural transformations in a dextran grafted-poly(N-isopropylacrylamide) copolymer/Au nanoparticles (D-g-PNIPAM/AuNPs) hybrid nanosystem in water have been observed. The laser induced local plasmonic heating of Au NPs leads to Lower Critical Solution Temperature (LCST) phase transition in D-g-PNIPAM/AuNPs macromolecules accompanied by their shrinking and aggregation. The hysteresis non-reversible character of the structural transformation in D-g-PNIPAM/AuNPs system has been observed at the decrease of laser intensity, i.e. the aggregates remains in solution after the turn-off the laser illumination. This is an essential difference comparing to the case of usual heating–cooling cycles when there is no formation of aggregates and structural transformations are reversible. Such a fundamental difference has been rationalized as the result of action of attractive optical forces arising due to the excitation of surface plasmons in Au NPs. The attractive plasmonic forces facilitate the formation of the aggregates and counteract their destruction. The laser induced structural transformations have been found to be very sensitive to matching conditions of the resonance of the laser light with surface plasmon resonance proving the plasmonic nature of observed phenomena.
关键词： Plasmon heating,Attractive optical forces,LCST phase transition,Au nanoparticles,Laser induced structural transformations,Dextran-graft-PNIPAM copolymer
更新于2025-11-19 16:56:42
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Direct Observation of Structural Evolution of Metal Chalcogenide in Electrocatalytic Water Oxidation
摘要： As one of the most remarkable oxygen evolution reaction (OER) electrocatalysts, metal chalcogenides have been intensively reported due to their high OER activities during the past few decades. It has been reported that electron-chemical conversion of metal chalcogenides into oxides/hydroxides would take place after OER. However, the transition mechanism of such unstable structures, as well as the real active sites and catalytic activity during OER for these electrocatalysts, has not been understood yet, which urgently needs a direct observation for the electrocatalytic water oxidation process, especially at nano or even angstrom scale. In this research, by employing advanced Cs-corrected transmission electron microscopy (TEM), a step by step oxidational evolution of amorphous electrocatalyst CoSx into crystallized CoOOH in OER has been in situ captured: irreversible conversion of CoSx to crystallized CoOOH is initiated on the surface of electrocatalysts with a morphology change via Co(OH)2 intermediate during OER measurement, where CoOOH is confirmed as the real active species. Besides, this transition process has also been confirmed by multiple applications of X-ray photoelectron spectroscopy (XPS), in situ Fourier-transform infrared spectroscopy (FTIR) and other ex situ technologies. Moreover, based on this discovery, a high-efficiency electrocatalyst of a nitrogen-doped graphene foam (NGF) coated by CoSx has been explored through a thorough structure transformation of CoOOH. We believe this in situ and in-depth observation of structural evolution in OER measurement can provide insights into the fundamental understanding of the mechanism for OER catalysts, thus enabling the more rational design of low-cost and high-efficient electrocatalysts for water splitting.
关键词： structural evolution,XPS,in situ TEM,water oxidation,cobalt chalcogenide
更新于2025-11-14 15:27:09
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One-Dimensional Mercury Halide Coordination Polymers Based on A Semi-Rigid N-Donor Ligand: Reversible Structural Transformation
摘要： Four one-dimensional (1D) mercury(II) halide coordination polymers have been synthesized by using a semi-rigid N-donor ligand, 2,2′-(1,4-phenylene)-bis(N-(pyridin-3-yl)acetamide) (1,4-pbpa). While [Hg(1,4-pbpa)Cl2·CH3OH]n, 1, forms a sinusoidal chain, the complexes [Hg(1,4-pbpa)X2]n (X = Cl, 2; Br, 3; I, 4) are helical. The sinusoidal 1 undergoes reversible structural transformation with helical 2 upon removal and uptake of CH3OH, which was accompanied with the conformation adjustment of the 1,4-pbpa ligand from trans anti-anti to trans syn-anti. Pyridyl ring rotation of the 1,4-pbpa ligand that results in the change of the ligand conformation is proposed for the initiation of the structural transformation.
关键词： mercury halide,structural transformation,bis-pyridyl-bis-amide,coordination polymer
更新于2025-11-14 15:13:28