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Photovoltaic Properties and Series Resistance of <i>p</i> -Type Si/Intrinsic Si/ <i>n</i> -Type Nanocrystalline FeSi <sub/>2</sub> Heterojunctions Created by Utilizing Facing-Targets Direct-Current Sputtering
摘要： p-Type Si/intrinsic Si/n-type nanocrystalline iron disilicide heterojunctions were created by utilizing facing targets direct-current sputtering at the pressure of 1.33 × 10?1 Pa that investigated the photovoltaic properties. They exhibited a large leakage current and a small energy conversion ef?ciency of 0.62%. From using the method of Nicollian and Brews, the series resistance (Rs) values at zero bias voltage were 7.40 Ω at 2 MHz and 7.57 Ω at 50 kHz, respectively, which were in agreement with that estimated by the means of Norde. From applying the method of Hill-Coleman, the interface state density (Nss) values were 3.15 × 1015 cm?2 eV?1 at 50 kHz and 8.93 × 1013 cm?2 eV?1 at 2 MHz. The obtained results revealed the presence of Rs and Nss at the junction interface, which should be the potential cause of spoiled photovoltaic performance in the heterojunctions.
关键词： Heterojunctions,Facing-Targets Direct-Current Sputtering,Nanocrystalline Iron Disilicide,Series Resistance,Interface State Density
更新于2025-11-14 17:28:48
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Luminescent Composites Based on Tetrafluoroethylene Copolymer Porous Films Produced by the Diffusion Embedding of Semiconductor Nanoparticles in a Supercritical Medium
摘要： A method for creating film composites based on a new material—a fibrous copolymer of tetrafluoroethylene and vinylidene fluoride—using the diffusion embedding of ready-made nanoparticles into a porous matrix in a supercritical (SC) carbon dioxide medium is developed. The method of cold or hot pressing of impregnated porous films was used at the final stage of creation of such composites. The peculiarities of the effect of the supercritical fluid treatment of porous copolymer films on the surface structure of pressed films are discussed. Luminescent composites with semiconductor nanoparticles of cadmium selenide and nanocrystalline silicon are obtained; their radiation covers a range of 500–1000 nm. The change in the luminescence properties of the resulting nanocomposites under the action of excitation laser radiation at 405 nm is demonstrated.
关键词： cadmium selenide,film composite,fibrous matrix,luminescent properties,diffusion embedding,nanocrystalline silicon
更新于2025-11-14 15:30:11
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Infrared Light Management Using a Nanocrystalline Silicon Oxide Interlayer in Monolithic Perovskite/Silicon Heterojunction Tandem Solar Cells with Efficiency above 25%
摘要： Perovskite/silicon tandem solar cells are attractive for their potential for boosting cell efficiency beyond the crystalline silicon (Si) single-junction limit. However, the relatively large optical refractive index of Si, in comparison to that of transparent conducting oxides and perovskite absorber layers, results in significant reflection losses at the internal junction between the cells in monolithic (two-terminal) devices. Therefore, light management is crucial to improve photocurrent absorption in the Si bottom cell. Here it is shown that the infrared reflection losses in tandem cells processed on a flat silicon substrate can be significantly reduced by using an optical interlayer consisting of nanocrystalline silicon oxide. It is demonstrated that 110 nm thick interlayers with a refractive index of 2.6 (at 800 nm) result in 1.4 mA cm?2 current gain in the silicon bottom cell. Under AM1.5G irradiation, the champion 1 cm2 perovskite/silicon monolithic tandem cell exhibits a top cell + bottom cell total current density of 38.7 mA cm?2 and a certified stabilized power conversion efficiency of 25.2%.
关键词： monolithic perovskite/silicon tandem solar cells,infrared photocurrent absorption,nanocrystalline silicon oxide interlayers
更新于2025-10-22 19:40:53
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Structural, optical and magnetic elucidation of co-doped of Nd+3 and Pr+3 on lithium nanoferrites and its technological application
摘要： LiNiCo spinel ferrites were prepared, by doping with rare earth metals Nd and Pr, according to micro-emulsion method. In order to study the effect of Nd and Pr, the crystal structure and magnetic properties of prepared ferrites were scrutinized in detail. The endorsement of single-phase spinel ferrites with the co-occurrence of orthophase was confirmed by XRD and FTIR. The average crystallite size varied with increasing the doped concentration of Nd and Pr, which is in the range from 28nm to 70nm. Magnetic properties were analyzed by VSM within range of -10000Oe and 10000Oe. MS and MR values decreased with the increase in concentration. The value of HC, MR, and MS showed stability for transformer core where electromagnetic interference is reduced. Hence synthesized ferrites LiNi0.35-yCo0.15PryNdxFe2-xO4 are suitable for transformers and induction.
关键词： Microemulsion,XRD,Li-Pr,Neodymium,Nanocrystalline ferrites,Praseodymium,Magnetic properties
更新于2025-09-23 15:23:52
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Molecular Functionalization of Planar Nanocrystalline and Porous Nanostructured Diamond to Form an Interface with Newborn and Adult Neurons
摘要： This article examines the ability of newly developed nanostructured porous boron-doped diamond (BDD) to form an interface with neural cells and the role of molecular functionalization by a polymer on this interface. Due to its high stability, biocompatibility, and electrical properties, BDD is a promising material for construction of neuroelectrodes. Nanostructuring and an increase in the surface specific area can further improve the sensitivity and performance of such electrodes. Here, porous BDD prepared in a multistep diamond deposition on a porous template consisting of a polymer and electrospun SiO2 fibers is examined. This work shows that this new material is biocompatible and does not exhibit any cytotoxicity on fibroblast cell lines. Further, this work shows that porous BDD supports regeneration of newborn and adult neurons when functionalized with poly-L-lysine.
关键词： nanocrystalline diamond,boron-doped diamond,enhanced surface area,neural interface,chemical functionalization
更新于2025-09-23 15:23:52
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Linear Birefringent Films of Cellulose Nanocrystals Produced by Dip-Coating
摘要： Transparent ?lms of cellulose nanocrystals (CNC) are prepared by dip-coating on glass substrates from aqueous suspensions of hydrolyzed ?lter paper. Dragging forces acting during ?lms’ deposition promote a preferential alignment of the rod-shaped CNC. Films that are 2.8 and 6.0 μm in thickness show retardance effects, as evidenced by placing them between a linearly polarized light source and a linear polarizer sheet in the extinction con?guration. Transmission Mueller matrix spectroscopic ellipsometry measurements at normal incidence as a function of sample rotation were used to characterize polarization properties. A differential decomposition of the Mueller matrix reveals linear birefringence as the unique polarization parameter. These results show a promising way for obtaining CNC birefringent ?lms by a simple and controllable method.
关键词： Mueller matrix,birefringence,nanocrystalline cellulose,nanostructured ?lms
更新于2025-09-23 15:22:29
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Ni doped noble-metal-free CdZnNiS photocatalyst for high-efficient photocatalytic hydrogen evolution reduction by visible light driving
摘要： In this paper, we report a method that the transition element nickel is doped into the interstitial position of CdZnS (CZS) nanoparticles for their photocatalytic hydrogen evolution activity boosting. It is demonstrated that CdZnNiS nanocrystalline materials (with 0.5 wt% of Ni) could achieve the highest photocatalytic H2-evolution activity of 25.4 mmol·g?1·h?1 in sulfide and sulfite solution under visible light which value is 1.16 times higher than that of Pt modified CdZnS particles (with 3 wt% of Pt). This work evidences the possibility of substitution of noble metal cocatalyst by adding a suitable inexpensive Ni to achieve high-efficient visible light driven water splitting hydrogen production.
关键词： Semiconductors,CdZnNiS nanocrystalline materials,Noble-metal-free cocatalyst,Gap doping,Nanocomposites,Water splitting
更新于2025-09-23 15:22:29
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Hydrogen Gas Sensing Characterizations Based on Nanocrystalline SnO<sub>2</sub> Thin Films Grown on SiO<sub>2</sub>/Si and Al<sub>2</sub>O<sub>3</sub> Substrates
摘要： High-quality nanocrystalline (NC) SnO2 thin films were grown on SiO2/Si and Al2O3 substrates using sol–gel spin coating method. The structural properties, surface morphologies and gas sensing properties of the NC SnO2 were investigated. XRD measurements showed a tetragonal rutile structure and the diffraction peaks for NC SnO2 thin films grown on Al2O3 substrates outperformed those of NC SnO2 films grown on SiO2/Si substrates. The surface morphology of the annealed SnO2 thin films at 500 oC appeared as polycrystalline with uniform nanoparticle distribution. Hydrogen (H2) gas sensing performance of the NC SnO2 was examined for H2 concentrations ranging from 150 ppm to 1000 ppm at different temperatures (room temperature, 75 and 125 oC) for over 50 min. The room temperature sensitivities for H2 gas sensors based on NC SnO2 thin films grown on Al2O3 and SiO2/Si substrates was 2570% and 600%, respectively upon exposure to 1000 ppm of H2 gas. While the sensitivity values at 125 oC increased to 9200% and 1950%, respectively.
关键词： Sensing,Room Temperature,Hydrogen,Nanocrystalline SnO2,Thin Films,Sol-Gel
更新于2025-09-23 15:22:29
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Phase Evaluation of Pure Nanocrystalline Barium Stannate by Two Different Milling Activations
摘要： Pure nanocrystalline BaSnO3 is prepared by two methods: mechanical activation (planetary ball milling) and mechanical hand mixing in agate mortar followed by sintering for both at 1350 °C/ 2 h. The phase formations during synthesis are analyzed by x-ray diffraction (XRD) studies and the crystallite size is measured by Scherrer’s formula from the major peaks of the diffractogram. The nanocrystalline barium stannate having single phase simple cubic perovskite structure is synthesized with a crystallite size about 50 nm. Fourier transform infrared spectroscopy (FTIR) is done to determine symmetric and asymmetric stretching of the bonds formed and co-ordination of the ions within crystal structure. FTIR studies justify the phases developed by XRD since the molecular signature and co-ordination of cations are verified. Microstructure and morphology are observed by scanning electron microscopy (SEM), while energy dispersive x-ray analysis (EDX) is done to determine the presence of the required element of composition formation. Ultra violet-visible spectroscopy (UV-VIS) shows absorption spectra of the sample within the UV region, while the band gap is calculated using the Tauc relation. The band gap evaluated for nanocrystalline barium stannate is about 2–2.78 eV for indirect transition, while for direct transition it is about 2.78–3.14 eV. The value is observed to be close to that of semiconductor-based materials.
关键词： FTIR,UV-VIS,nanocrystalline barium stannate,EDX,high energy planetary milling,XRD,SEM
更新于2025-09-23 15:22:29
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The Effect of Precursor Composition on the Structural Properties of Nanocrystalline Diamond Films
摘要： Nanocrystalline diamond (NCD) films were grown by hot filament CVD and the precursor composition dependence of the structural properties was examined. Films grown at 1 and 2 CH4 Vol% were found to be NCD layers with grain sizes of ～23–25 nm while films grown at 3–5 Vol% were identified as the mixtures of microcrystalline diamond and graphitic phase. The sp2/sp3 bonded carbon ratio in the grown films increased as the CH4 content increased up to 3 Vol% and then decreased beyond 4 Vol%. Microstructure and deposition rate were also found to be affected by the precursor composition and the NCD film grown at 1 CH4 Vol% showed a very dense microstructure and the highest deposition rate of ～3 nm/min.
关键词： Precursor Composition,Structural Properties,Nanocrystalline Diamond
更新于2025-09-23 15:22:29