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Optical properties of 2D photonic structures fabricated by direct laser writing
摘要： This paper presents the results of fabrication and investigation of different 2D photonic structures with the square C4v, hexagonal C6v, and pentagonal local C5v symmetry. The samples were created using the direct laser writing technique. The number of submicron scatterers varied from 25 to 10,000, and the lattice parameters varied in different samples in the range of 0.5 μm ≤ a ≤ 8.0 μm. Our experimental and theoretical studies demonstrate that 2D photonic structures reveal many remarkable optical effects. Created ordered and disordered photonic structures demonstrate a great variety of optical phenomena observed on a far-field screen placed behind the sample. When the random fluctuations of the orientation for individual rods were introduced to the perfect fishnet photonic structure, a crossover from Laue diffraction to speckle patterns was observed and investigated.
关键词： Laue diffraction,Light scattering,Photonic structure,Direct laser writing,SEM images,Metasurface
更新于2025-09-19 17:13:59
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Fabrication and characterization of PSi/nanometal hybrid structures by laser for CO gas sensor
摘要： Mesoporous silicon (mesoPSi) layers fabricated by the photoelectrochemical etching (PECE) method in hydrofluoric acid (HF) are active as carbon monoxide gas sensors. The modified porous silicon (PSi) can be used with noble metals to manufacture an effective gas sensor. Embedded gold, platinum, and palladium nanoparticles Au, Pt, and Pd-NPs could modify the surface morphology of mesoPSi and form mesoPSi/AuPtPd-NPs hybrid structures through a simple and dipping process in fixed salt concentrations. The morphology of the hybrid structures has been studied using scanning electron microscopy and X-ray diffraction. The prepared gas sensor has measured the electrical characteristics at room temperature. Shape, nanoparticle size, and specific surface area strongly influenced the current–voltage characteristics. The results show that Au, Pd, and Pt-NPs sizes prepared by the dipping process for mesopore-like structures were in the range from 0.64 to 7.53 nm. Besides, considerable improvements in the response, recovery times and sensitivity of gas sensor were noticed when decreasing the incorporated Au, Pd, and Pt-NPs to the mesoPSi matrix.
关键词： SEM,Gas sensing,Photoelectrochemical,AuPtPd-NPs hybrid structures,MesoPSi
更新于2025-09-19 17:13:59
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Binary transition metal sulfides as an economical Pt-free counter electrodes for dye-sensitized solar cells
摘要： Binary CuxCoySz sulfide based Pt-free counter electrodes (CE) were prepared in one-step solvothermal synthesis process. The obtained CEs were characterized by SEM, XRD, and Raman spectroscopy methods. EDX analysis showed uniform distribution of Cu, Co and S. SEM images revealed different level of coverage of the FTO glass by the binary metal sulfide products. DSSCs were constructed using proposed CEs with N719 dye, and their photovoltaic and electrochemical performances were assessed against Pt reference cell. The efficiency of the CuxCoySz-3 CE produced an 11% improvement of its photovoltaic efficiency compared to the reference cell.
关键词： Cu-Co-S complex,SEM,XRD,Solvothermal synthesis,Raman
更新于2025-09-16 10:30:52
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Thermo mechanical analyses and characterizations of TiNiCu shape memory alloy structures developed by laser additive manufacturing
摘要： Three di?erent compositions of TiNiCu (Ti50Ni (50?x) Cux (x = 10, 20 and 30)) shape memory alloys (SMA) were developed using an intelligent manufacturing technique of laser additive manufacturing (LAM). Based on a numerical analysis the nature and amount of residual stress ?ow was predicted. By implementing ?nite element method (FEM) with Gaussian distributed volumetric heat source, the deposition process was simulated. The numerical and experimental analyses were at par with each other. The developed samples were subjected to several characterizations in order to determine the best among them. Scanning electron microscopy (SEM), atomic force microscopy (AFM), were used to study the surface morphology of the samples. The mechanical properties were studied using micro-hardness test and compression test. X-Ray di?raction (XRD) was deployed to investigate the crystalline nature of the samples. The phase transformation ability of the samples were determined by di?erential scanning calorimetry (DSC). The SEM revealed the deposition of all three samples to be homogeneous. The AFM results showed the grain size of TiNiCu10 to be 20.12 nm, the smallest among the samples. The micro-hardness and ultimate strength of TiNiCu10 was found to be 242 VHN and MPa respectively. XRD reveals the presence of three step transformation for TiNiCu20 sample. From the results, LAM process was considered as a successful methodology in developing TiNiCu bulk SMA structures. The properties of laser additive manufactured TiNiCu10 was found to be the best among the developed samples.
关键词： DSC,TiNiCu,SEM,XRD,Laser additive manufacturing,Shape memory alloy
更新于2025-09-16 10:30:52
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Influence of dopant concentration on the electronic band gap energy of Yb-ZrSe <sub/>2</sub> thin films for photovoltaic application via electrochemical deposition technique
摘要： This research focus on the Influence of Dopant Concentration on Polycrystalline Ytterbium-doped ZrSe (Yb-ZrSe) material for possible photovoltaic application using the electrochemical deposition method. The cationic precursor was an aqueous solution of 0.01 mol ZrOCl2.8H2O while the anionic precursor was 0.15 mol selenium was prepared by dissolving with 5 ml of Hydrochloric acid (HCl), and then 0.05 mol Yb (NO3)3.5H2O was used as the dopant. The films were characterized using UV-1800 Visible Spectrophotometer, Bruker D8 Advance x-ray diffractometer with Cu Kα line (λ = 1.54056 ?) in 2θ range from 10°–90°and Scanning Electron Microscopy. X-ray diffraction (XRD) of the deposited films on FTO substrate studies reveals that films are polycrystalline by exhibiting diffraction peaks at (111), (200), (200) and (210) corresponds to the following angle (27.00°), (38.01°), (46.02°), (66.02°). (SEM) revealed that the grain size was uniformly distributed on the surface of the substrate. The optical band gap energy 1.57 eV was obtained.
关键词： XRD,optical properties,Yb doped ZrSe,ECD,SEM
更新于2025-09-16 10:30:52
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Pyrocatechol violet sensitized Ho-TiO <sub/>2</sub> /ZnO nanostructured material: as photoanode for dye sensitized solar cells
摘要： In this work TiO2, Holmium doped (Ho-TiO2) Titanium oxide nanoparticles (NPs) and the corresponding nanostructured combinations (Ho-TiO2/ZnO NC) were successfully synthesized through sol gel method and re?ux techniques respectively. The prepared nano materials were characterized with the help of x-ray diffraction Analysis (XRD), UV–visible spectroscopy, Scanning Electron Microscopy (SEM), Energy dispersive x-ray Analysis (EDX) and Fourier Transform infrared spectroscopy (FT-IR). The absorption spectra of nano materials were used for band gaps calculation. The band gap of pure TiO2 NPs was found to be 3.10 eV which was effectively tuned to 2.65 eV by the doping of Holmium at different concentrations. XRD patterns con?rmed the crystalline nature and purity of the synthesized nano materials. Morphology and elemental composition of the material were investigated using SEM and EDX respectively. FTIR helped in detecting the functional groups and grafting of the dye on the surface of nanoparticles. The nano materials were used as Photo-anodes in dye sensitized solar cells (DSSC). Pyrocatechol Violet dye was used as a photo-sensitizer. P3HT (polymer), a hole conducting polymer, was employed as a solid state electrolyte. I–V measurements were used for characterization of fabricated solar cells. Ho-TiO2/ZnO nanomaterial photosensitized with Pyrocatechol violet dye gave the highest percentage ef?ciency of 1.51. Other characteristic parameters of the fabricated devices such as short circuit current (Jsc), open circuit voltage (Voc), maximum power point (Mpp) and ?ll factor were found to be 11.2 mA cm?2, 0.41 V, 1.55(mW cm?2) and 0.33 respectively.
关键词： I–V curve,?ll factor,dye sensitized solar cell,sol gel method,SEM,pyrocatechol violet
更新于2025-09-16 10:30:52
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Caries removal with Er:YAG laser followed by dentin biomodification with carbodiimide and chitosan: Wettability and surface morphology analysis
摘要： This study aimed to investigate dentin wettability and surface morphology after selective removal of carious lesion by erbium-doped yttrium aluminum garnet (Er: YAG) laser, followed by dentin biomodification with carbodiimide (EDC) and chitosan (CHI). Seventy-eight bovine dentin specimens were submitted to caries induction. Specimens were distributed according to methods of carious removal (n = 39): bur at low-speed (40,000 rpm) or Er:YAG laser (noncontact mode, 250 mJ/pulse and 4Hz). All specimens were etched with 35% phosphoric acid, and subdivided according to dentin biomodification (n = 13): Control (no biomodification), EDC or CHI. The contact angle (n = 10) between adhesive system (3M ESPE) and dentin surface was measured by a goniometer. Eighteen specimens (n = 3) were analyzed by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey's test (α = .05). The method used to remove carious lesion did not influence the wettability of dentinal surface (p = .748). The angles produced on the remaining dentin after biomodification were influenced (p = .007). CHI promoted higher contact angles (p = .007) and EDC did not differ from the control group (p = .586). In the bur-treated group, most tubules were open, regardless of which biomodifier was used. Laser modified the organic matrix layer. CHI promoted partially closed tubules in some areas while EDC exposed dentinal tubules. Regardless of which method was used for selective removal of carious lesion, biomodification with EDC did not affect the dentin wettability, whereas CHI changed the wettability of remaining dentin. Both biomodifiers promoted a slight change on dentin morphology.
关键词： contact angle,biomaterials,SEM,caries-affected dentin,EDC
更新于2025-09-12 10:27:22
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Highly reliable and transparent Al doped Ag cathode fabricated using thermal evaporation for transparent OLED applications
摘要： Here, we report a highly reliable and transparent cathode (TC) for transparent organic light emitting diode (TOLED) applications. The cathode layer is fabricated by co-deposition of silver (Ag) and aluminum (Al) metals using thermal evaporation. The atomic percentages of Al and Ag are fixed at 96 at% and 4 at%, respectively. TC shows transmittance at 520 nm (T@520nm) of 83.5% and sheet resistance as low as 7.0 Ω/□. Almost no specific agglomeration of Ag:Al (4%, 14 nm) is noticed by the thermal annealing of fabricated cathode at 85 °C, 240 h. The fabricated TOLED with this Ag:Al (4%, 14 nm) cathode shows an excellent electron injection property with a T@520nm of 83.5%, and achieved current efficiencies of 36 and 18 cd/A from bottom and top sides emissions, respectively. It is argued that the Al-doped Ag film could become an effective, feasible alternative to the existing transparent conducting electrode for TOLED applications.
关键词： Ag:Al cathode,SEM and XPS measurements,Transparent OLED,transparent cathode
更新于2025-09-12 10:27:22
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New process of tempering color printed glass by using laser irradiation
摘要： Colored glass products with various printing technologies are becoming more important in industry. The aim is to achieve individual solution in a very short delivery time. Conventional thermal treatment of burning glasses in oven for tempered color printing has predominant issues with high time consumption, energy consumption and manufacturing cost. It requires alternative process development. This paper proposes laser process to overcome issues in conventional treatment with the latest results of tempering colored glass. Samples have been analyzed with the scanning electron microscope (SEM). Two different laser systems have been applied and the glass has been printed with black paste.
关键词： scanning electron microscope (SEM),glass,printing technologies,laser material processing,pigment paste,surface treatment
更新于2025-09-12 10:27:22
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Development of a Hybrid Chitosan- and Niacinamide-Coupled ZnO Nanoparticle Composite for Sun Protection Application
摘要： Zinc oxide nanoparticles (ZnO) have long been utilized as UV-protective sunscreen components due to their high durability and lower skin irritation while maintaining capability for blocking UV rays. However, the dispersal and transparency properties of ZnO need to be enhanced in order to improve the capacity for creating effective sunscreen through control of the physiochemical properties of ZnO. In this study, chitosan or niacinamide, which are suitable functional cosmetic compounds and effective skin lightening agents, are combined with ZnO for the development of better UV-protective products. Each biocompatible coating material is individually attached on its surface after the synthesis of ZnO. The size is 70 nm using the sol-gel method. Their morphology and chemical structure are characterized by FT-IR, XRD, SEM, TEM, TGA, and zeta potential. The results indicate that approximately 50% of chitosan and 5% niacinamide were coated on the ZnO. To confirm the capacity of each surface-coated ZnO with chitosan and niacinamide as a sunscreen, we measured their transmission, reflectance, and sun protection factor (SPF) using a UV spectrophotometer and SPF. As a result, the niacinamide-coated ZnO shows remarkably lower transmission and high reflectance against UV rays than that of bare ZnO and chitosan-coated ZnO. Furthermore, niacinamide-coated ZnO exhibits great lightening effects. Consequently, these results demonstrate that niacinamide coating is highly effective for the production of sunscreen emulsions.
关键词： Zinc oxide nanoparticles,TEM,FT-IR,SEM,XRD,UV-protective sunscreen,TGA,chitosan,SPF,sol-gel method,zeta potential,niacinamide,sun protection factor
更新于2025-09-12 10:27:22