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Investigation the effect of doping concentration in Ruthenium-doped TiO <sub/>2</sub> thin films for solar cells and sensors applications
摘要： Thin films of Ru doped TiO2 have been deposited on glass substrates at different doping concentration (0.05, 0.07, 0.09, 0.11 mol l?1) by the sol gel method. The prepared thin films were studied: their structural, morphological, optical and photocatlytic properties. The XRD spectra confirm that all the samples have anatase phase with preferential orientation along (101) plane. The position of (101) peaks shift to higher angles with increase doping concentration and 0.07 mol l?1 sample have a sharp and high intensity diffraction peak. Due to condensation and agglomeration effect. The thickness of the thin films increases from 110 nm to 255 nm with the increment of Ru concentrations. AFM images show that the films had good quality and pyramidal shape was distributed over their entire surface. Transmittance and absorbance spectra of the un-doped and Ru doped TiO2 thin films were recorded by UV–vis spectrometer. The optical band gap of the thin films increases from 3.66 eV to 3.85 eV as the Ru amount increases; this is due to the Moss-Burstein effect. Calculated results show that both the excitation coefficient (k) and refractive index (n) decreases with wavelength at all Ru concentration. Optical conductivity can improve after doping which can be a suitable material for use in sensor and solar cell applications. The photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under visible and sun light. The results revealed that the photocatalytic activity under sun light was higher comparing to UV light for all films. Ru doped TiO2 thin films enhance the efficiency of its photocatalytic activity. It was found that the percentage of degradation was higher in 0.11 mol l?1 Ru doped TiO2 when compared with other films.
关键词： doping,sol-gel,Ruthenium,thin film,TiO2
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Symposium on Applications of Ferroelectrics (ISAF) - Lausanne, Switzerland (2019.7.14-2019.7.19)] 2019 IEEE International Symposium on Applications of Ferroelectrics (ISAF) - Vibrating Piezoelectric Energy Conversion Efficiency of Sol-Gel PZT Films with Various Crystal Orientations on MEMS Buckled Diaphragm Structures
摘要： Vibrating energy conversion efficiency was investigated on piezoelectric transducers fabricated on MEMS buckled diaphragm structures from the viewpoint of crystal orientation of sol-gel derived lead-zirconate-titanate (PZT) films. The crystal orientation dominates in-plane stress and spontaneous polarization direction of the PZT films. The in-plane stress affects the static buckling of the diaphragm where a large convex buckling results in a high mechanical conversion efficiency from the flexural vibration to the in-plain vibration. The polarization direction affects the intrinsic piezoelectric conversion efficiency. The crystal orientation of the sol-gel PZT was controlled through pyrolysis temperature between 250?C and 350?C, resulting in a texture variation from (100)-oriented films to (111)-oriented ones. Highly (111)-oriented films showed large polarizations but small buckling deflections, while highly (100)-oriented films showed vice versa. Intermediately textured films with 40–45% (111)-orientation index showed the highest conversion efficiency.
关键词： Piezoelectric,Sol-gel,Residual stress,Buckling,PZT,Polarization,Energy conversion,Diaphragm
更新于2025-09-19 17:13:59
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Novel KFeO<sub>2</sub> nanoparticles for dye-sensitized solar cell
摘要： Novel KFeO2 nanoparticles for dye-sensitized solar cell. Environmentally clean and green source of energy is solar energy that can meet the increasing demand for energy. Recent trends in solar energy reflect that delafossite materials getting more attention because of its low-cost production and easy method of synthesis, non-toxic nature, environment-friendly nature, degradability compared to the silicon. In this direction, delafossite KFeO2 nanoparticles have synthesized by chemical method and used as photo-anode material for dye-sensitized solar cells (DSSC). The structural, morphological, optical and photovoltaic properties of KFeO2 nanoparticles have been investigated. Transmission electron microscopy (TEM) study reveals that the KFeO2 nanoparticles exhibit spherical morphology with particle size 12 nm. Rietveld refinement of x-ray diffraction (XRD) patterns of KFeO2 reflects, its orthorhombic phase with Pbca space group. The optical study reveals that the bandgap of the KFeO2 nanoparticles lying in the visible range of spectrum, i.e., 1.88 eV. The DSSC has been fabricated using KFeO2 nanoparticles. The power conversion efficiency parameters is 0.84 V; 4.72 mA/cm2; 64% and 2.54% respectively, for open-circuit voltage (VOC), short circuit current–density (JSC), fill factor (FF) and Power conversion efficiency for fabricated DSSC. It has been found that the efficiency of fabricated DSSC has been decrease to 2.27% after 45 days.
关键词： Dye sensitized solar energy materials,KFeO2,Sol-gel synthesis,Nanoparticles
更新于2025-09-19 17:13:59
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Roughness and wettability properties of plain and silica-coated copper surfaces textured with picosecond laser
摘要： Many recent studies have investigated the mechanism of wettability transition of laser-textured copper surfaces on di?erent materials. Furthermore, several such studies have focused on approaches to accelerate wettability transition from hydrophilicity to hydrophobicity, such as temperature annealing and the use of chemical solutions. However, few researchers have focused on maintaining the initial hydrophilicity of laser-textured surfaces. This study presents a hybrid surface modi?cation method involving chemical bath deposition and ultrafast laser. First, the selected copper substrates are modi?ed using the sol-gel method through dip coating. Subsequently, the coated copper surfaces are irradiated with a picosecond laser. After laser texturing, bumpy structures are formed, and SiO2 nanoparticles can be sintered on the surfaces. Thus, the original hydrophilicity can be maintained, and the surface roughness can be enhanced simultaneously. By using this hybrid modi?cation method, a heterogeneous surface with high-precision patterns can be obtained. Moreover, the mechanism of wettability transition of laser-textured copper surfaces with di?erent laser ?uences is discussed using the Wenzel and Cassie Baxter wetting model by analyzing the chemical composition and surface morphology of the treated surfaces.
关键词： Roughness,Copper,Laser texturing,Wettability,Picosecond laser,Sol-gel
更新于2025-09-19 17:13:59
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Controlled gel research: the effect of ethanol for delaying the polycondensation of tetraethyl orthosilicate-dimethyldiethoxysilane
摘要： In this study, the effect of ethanol for delaying the polycondensation of silanol in the co-hydrolysis-condensation of tetraethyl orthosilicate-dimethyldiethoxysilane was first explored and demonstrated by varying the amount of ethanol under low-water content and acid-catalyzed. On the basis of this, the controllability of the sol-gel process is realized, and the calculation formula of the gel formation time is provided. The experiment shows that the storage gel time and the reaction gel time are extended from 75 h to at least 4584 h, or from 20 to 65 h with the increase of ethanol concentration, respectively. And we observed the microscopic process of solution-sol-gel transition by light transmission microscope. The sol-gel process established in this experiment gives a mechanism reference for future research.
关键词： Polycondensation,Sol-gel process,Delay,Gel time,Controllability
更新于2025-09-16 10:30:52
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Formation Of PbSe – ZnO Thin Film Based Heterostructure For Solar Cell Applications
摘要： A new type of excitonic solar cell based on heterojunctions between PbSe semiconducting thin film and thin ZnO film has been fabricated. These solar cells can generate large photocurrents and higher photovoltages compared to Schottky cells assembled with similar nanocrystal films. The n-type and p-type nanomaterials such as ZnO and PbSe were synthesized by sol-gel method. The synthesized nanoparticles were coated over the ITO substrate by thermal evaporation method. The heterojunction thin films were annealed at 400 °C to form a p-n junction. Device performance was analyzed using semiconductor parameter analyzer (SPA) under the bright and dark field illumination. The conductivity was estimated from the sheet resistance value by using Four Probe Method. The material coated over the substrate and its crystallinity was identified by using thin film XRD and the nature of material coated was analyzed by Hall Effect measurement system. The thickness of the film coated over the substrate was determined by cross-section of FESEM analysis. The solar cell performance was carried out by differentiating the I-V characteristics under bright and dark field light illumination.
关键词： Thermal evaporation,Sol-gel,Device performance and Analysis,Solar cell
更新于2025-09-16 10:30:52
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Synthesis of β-SiC powders by the carbothermal reduction of porous SiO2–C hybrid precursors with controlled surface area
摘要： SiO2–C precursors with various surface areas were derived from tetraethyl orthosilicate and phenolic resin as Si and C sources, respectively, by a modi?ed sol–gel process using the in situ precipitation of phenol resin in a prepared wet gel. The surface area of the SiO2–C precursors was varied from 20 to 175 m2/g by changing the C/Si molar ratio in the preform. β-SiC powders were synthesized using carbothermal reduction in vacuum at the temperature range of 1200–1600 °C. The e?ects of the temperature and heat treatment time as well as that of the surface area of the preform on the formation of β-SiC powders were studied. It was determined that the formation of β-SiC started at 1200 °C and was considerably promoted as the heat treatment temperature and time further increased during the carbothermal reduction of SiO2–C preforms with high surface area. When high surface area SiO2–C preforms were used, highly crystalline SiC powders were synthesized at 1600 °C in vacuum with a high yield of 85%.
关键词： Meso-macro porous,Carbotermal reduction,Sol–gel method,SiC,Synthesis
更新于2025-09-16 10:30:52
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Novel Gd3+-doped silica-based optical fiber material for dosimetry in proton therapy
摘要： Optical fibers hold promise for accurate dosimetry in small field proton therapy due to their superior spatial resolution and the lack of significant Cerenkov contamination in proton beams. One known drawback for most scintillation detectors is signal quenching in areas of high linear energy transfer, as is the case in the Bragg peak region of a proton beam. In this study, we investigated the potential of innovative optical fiber bulk materials using the sol-gel technique for dosimetry in proton therapy. This type of glass is made of amorphous silica (SiO2) and is doped with Gd3+ ions and possesses very interesting light emission properties with a luminescence band around 314 nm when exposed to protons. The fibers were manufactured at the University of Lille and tested at the TRIUMF Proton Therapy facility with 8.2–62.9 MeV protons and 2–6 nA of extracted beam current. Dose-rate dependence and quenching were measured and compared to other silica-based fibers also made by sol-gel techniques and doped with Ce3+ and Cu+. The three fibers present strong luminescence in the UV (Gd) or visible (Cu,Ce) under irradiation, with the emission intensities related directly to the proton flux. In addition, the 0.5 mm diameter Gd3+-doped fiber shows superior resolution of the Bragg peak, indicating significantly reduced quenching in comparison to the Ce3+ and Cu+ fibers with a Birks’ constant, kB, of (0.0162 ± 0.0003) cm/MeV in comparison to (0.0333 ± 0.0006) cm/MeV and (0.0352 ± 0.0003) cm/MeV, respectively. To our knowledge, this is the first report of such an interesting kB for a silica-based optical fiber material, showing clearly that this fiber presents lower quenching than common plastic scintillators. This result demonstrates the high potential of this inorganic fiber material for proton therapy dosimetry.
关键词： Bragg peak,dosimetry,Gd3+-doped silica,optical fibers,quenching,sol-gel technique,proton therapy
更新于2025-09-16 10:30:52
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Influence of Calcination Temperature on the Performance of TiO<sub>2</sub> Films in Dye-Sensitized Solar Cells
摘要： In this work, the effects of calcination temperature on the photovoltaic performance of TiO2 films prepared with non-hydrolytic sol-gel method were reported. The optimal photovoltaic performance of DSCs was obtained by annealing TiO2 film at 550 °C. The short-circuit current (Jsc), open-circuit voltage, fill factor (FF) and energy conversion efficiency were 15.68 mA·cm-2, 0.71 V, 0.62 and 6.83%, respectively.
关键词： dye-sensitized solar cell,photoanode film,performance,calcination temperature,non-hydrolytic sol-gel titanium dioxide
更新于2025-09-16 10:30:52
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Optical Thin Films of Metal Oxides Produced by the Sol-Gel Method for Photovoltaic Applications
摘要： The use of thin films in optoelectronic and photovoltaic devices is aimed at improving the physical properties of the substrate material. The modification of the surface of the silicon substrate is thus one of the greatest challenges in research on photovoltaic materials, in order to achieve even greater efficiency or better adapt their properties depending on the application. The technologies of applying layers vary depending on the effect to be obtained and the material from which the layer is formed. In practice, the most common method is chemical vapor deposition and physical vapor deposition, and the most commonly applied optical materials are SiO2, TiO2 and Si3N4.This paper presents the results of investigations on morphology and optical properties of the prepared aluminium oxide thin films. Thin films were prepared with use of sol-gel spin coating method. Surface morphology studies were carried out using an atomic force microscope. To characterize the surface of the thin films, 3D images and histograms of the frequency of individual inequalities were made. In order to characterize the optical properties of Al2O3 thin films, the reflectance and light transmission tests were performed using a spectrophotometer. Optical constants were determined using a spectroscopic ellipsometer. Results and their analysis show that the sol-gel method allows the deposition of homogenous thin films of Al2O3 with the desired geometric characteristics and good optical properties. Uniform, continuous thin layers with a roughness not exceeding a few nanometres were deposited. Their deposition enabled to reduce the reflection of light from the polished substrate below 15% in a wide range (425-800nm) while maintaining high transparencies (over 90%). The obtained results causes that mentioned thin films are good potential material for optics, optoelectronics and photovoltaics.
关键词： metal oxide,thin films,sol-gel
更新于2025-09-16 10:30:52