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- 摘要
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Effects of platinum photodeposition time on the photoelectrochemical properties of Fe2O3 nanotube electrodes
摘要： A photo-assisted deposition method for the deposition of platinum nanoparticles on Fe2O3 nanotubes (Pt/Fe2O3), prepared by anodizing, has been developed. The chemicophysical properties and elemental composition of the synthetic Pt/Fe2O3 samples have also been determined. The investigation of the photoelectrochemical properties of the prepared Pt/Fe2O3 samples showed their greatly increased photocurrent density for photoelectrochemical (PEC) water splitting compared to bare Fe2O3. Therefore, the deposition of Pt is effective on the enhancement of the PEC response. In addition, the effect of the Pt photodeposition time on water splitting capability was studied. The current density produced by sample HPt3 was 220 lA/cm2 at +0.4 V vs. Ag/AgCl, which is 2 times higher than that of the bare Fe2O3 nanotube samples (105 lA/cm2, at +0.4 V vs. Ag/AgCl).
关键词： Platinum,Fe2O3 nanotube,Deposition,Thin films,Photoelectrochemical
更新于2025-09-10 09:29:36
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Optical optimization of a multi-layer wideband anti-reflection coating using porous MgF2 for sub-micron-thick CIGS solar cells
摘要： The optical losses associated with sub-micron absorbers in CIGS solar cells can be reduced by light management techniques. 3-D optical modelling was used to optimize light in-coupling and internal rear reflectance in a 750-nm thick CIGS reference solar cell. At the front side, an effective medium approximation (EMA) approach for describing optical properties of a MgF2-based anti-reflection coating (ARC) was applied. Taking reflectance as the cost function and sequential nonlinear programming as the optimization algorithm, an optimal porous-on-compact double-layer ARC was determined. This led to a wideband light in-coupling with a 6.8% improvement in the photo-current density (Jph) with respect to the reference solar cell without ARC. Considering the variation of the sunlight direction due to day and seasonal changes, different light incidence angles were investigated. The results indicate that in this case, our designed double-layer ARC outperforms the standard compact MgF2 single-layer ARC. By using the EMA approach, the amount of computational memory can be reduced by a factor of 30, shortening the simulation time from four days to one hour. At the rear side of the cell, a point-contacted MgF2/Al2O3 reflector, in combination with our proposed front ARC, enhances the Jph by 11.3% considering the same reference solar cell. Compared to a much thicker cell (1600-nm thick absorber) with no light management applied, our front-and-rear optical approaches more-than-compensate optical losses resulting from using thinner absorbers. This design is suitable for industrial uptake and practical to realize. Additionally, the approach of using EMA for double-layer ARC optimization is innovative with respect to other ARC approaches applicable to not only chalcopyrite photovoltaic technologies.
关键词： Thin films,Antireflection coatings,Light management,Photovoltaic
更新于2025-09-10 09:29:36
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Tuning spin-charge interconversion with quantum confinement in ultrathin bismuth films
摘要： Spin-charge interconversion (SCI) phenomena have attracted a growing interest in the field of spintronics as a means to detect spin currents or manipulate the magnetization of ferromagnets. The key ingredients to exploit these assets are a large conversion efficiency, the scalability down to the nanometer scale, and the integrability with optoelectronic and spintronic devices. Here, we show that, when an ultrathin Bi film is epitaxially grown on a Ge(111) substrate, quantum size effects arising in nanometric Bi islands drastically boost the SCI efficiency, even at room temperature. Using x-ray diffraction, scanning tunneling microscopy, and spin- and angle-resolved photoemission, we obtain a clear picture of the film morphology, crystal, and electronic structures. We then directly probe SCI with three different techniques: magneto-optical Kerr effect to detect the charge-to-spin conversion generated by the Rashba-Edelstein effect (REE), optical spin orientation, and spin pumping to generate spin currents and measure the spin-to-charge conversion generated by the inverse Rashba-Edelstein effect (IREE). The three techniques show a sizable SCI only for 1–3-nm-thick Bi films corresponding to the presence of bismuth nanocrystals at the surface of germanium. Due to three-dimensional quantum confinement, those nanocrystals exhibit a highly resistive volume separating metallic surfaces where SCI takes place by (I)REE. As the film size increases, the Bi film becomes continuous and semimetallic leading to the cancellation of SCIs occurring at opposite surfaces, resulting in an average SCI that progressively decreases and disappears. These results pave the way for the exploitation of quantum size effects in spintronics.
关键词： Rashba-Edelstein effect,bismuth films,spintronics,quantum size effects,Spin-charge interconversion
更新于2025-09-10 09:29:36
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Particulate Coatings with Optimized Haze Properties
摘要： The haze factor, which describes the fraction of light that is scattered when passing through a transparent material, is of general importance for any optical device, from milk glass shielding visibility while providing ambient lighting to solar cells that are optimized by sophisticated light management layers. Often, such active layers are fabricated from particulate materials that are deposited as thin films on a substrate. Here, the effect of structural arrangement, position, and orientation of particles on the resulting haze factor is investigated. A mathematical optimization model that iteratively alters the particle layer structure to maximize or minimize the haze factor for a range of optimization scenarios is designed. Colloidal self-assembly techniques are then used to replicate typical particle structures found in the optimized designs and correlate the macroscopically measured haze values to the predictions of the optimization. The results indicate general design rules that control the haze value in particle layers. Non close-packed structures with distributed scatterers and high degrees of order provide minimal haze values while chain-like arrangements and small clusters maximize the haze of a particle layer. Finally, the findings are transferred to metal nanohole films as model transparent electrodes with controlled haze values.
关键词： haze factor,electromagnetic scattering,thin films,colloidal lithography,colloids,mathematical optimization
更新于2025-09-10 09:29:36
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[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Effect of Fe Doping on Structural, Optical and Electrical Properties of Zno Thin Films
摘要： Zn1-xFexO (0 ≤ x ≤ 0.20) thin films were prepared by spray pyrolysis technique. We describe the effect of Fe doping on structural, surface morphology, optical and electrical properties of the sprayed films. XRD analysis indicates that the films are polycrystalline and textured with c axis of the wurtzite structure along transmittance growth direction. UV-Visible measurements show that the films are highly transparent in the visible region. The lowest electrical resistivity of 3.54×10-3 Ω.cm was obtained for Zn0.97Fe0.03O sample.
关键词： Thin Films,ZnO,Spray,Iron
更新于2025-09-10 09:29:36
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Fabrication of Thin Functional Films by Solution Aerosol Thermolysis (SAT)
摘要： The technique of air-pressurized solution spray pyrolysis was used to fabricate thin films of La0.75Sr0.25MnO3 (LSM) and CuO-CeO2 on dense YSZ substrates. These films are widely used in several applications such as high temperature ceramic electrochemical cells, membranes and sensors. The technique was tailored to produce films with differing morphologies and thicknesses in terms of applied substrate deposition temperatures. The droplet drying and decomposition kinetics is discussed as a function of substrate temperature, given the other processing parameters (i.e. nozzle to substrate distance, solution flow rate, air pressure/air flow rate and deposition time) constant. A graph-map is drawn containing morphology and quality of fabricated films in terms of substrate temperatures and concentration levels for this particular set of precursor salts in aqueous solutions. Within the deposition temperature range examined, film thicknesses were found to decrease with increasing substrate temperature along with a concomitant change in quality from irregular texture to smoother and of more uniform thickness. A maximum deposition temperature of about 280?C was identified for 0.025M concentration for both types of films which correlates quite well with the Leidenfrost point measured in the literature for solvents with boiling point less than 150?C.
关键词： YSZ substrates,spray pyrolysis,thin films,LSM,CuO-CeO2,solution aerosol thermolysis
更新于2025-09-10 09:29:36
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Ellipsometric Analysis of Cadmium Telluride Films’ Structure
摘要： Ellipsometric analysis of CdTe films grown on Si and CdHgTe substrates at the “hot-wall” epitaxy vacuum setup has been performed. It has been found that ellipsometric data calculation carried out by using a simple one-layer film model leads to radical distortion of optical constants spectra: this fact authenticates the necessity to attract a more complicated model that should include heterogeneity of films. Ellipsometric data calculation within a two-layer film model permitted to conclude that cadmium telluride films have an outer layer that consists of the three-component mixture of CdTe, cavities, and basic matter oxide. Ratio of mixture components depends on the time of deposition, that is, on the film thickness. The inner layer consists of cadmium telluride.
关键词： heterogeneity,optical constants,two-layer model,ellipsometric analysis,CdTe films
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - GRACE: Developing Electrical Characterisation Methods for Future Graphene Electronics
摘要： GRACE — Developing electrical characterisation methods for future graphene electronics is a 2016 Normative Joint Research Project of the European Metrology Programme for Innovation and Research. The project focuses on the measurement of the electrical properties of graphene. Its objectives are to develop validated measurement methods and protocols, including fast-throughput examples. The work is performed in collaboration with international standardisation committees, with an aim to initiate and develop dedicated documentary standards.
关键词： Conductive films,Standardization,Metrology,Electric variables,Graphene,Electronics industry
更新于2025-09-10 09:29:36
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Photoluminescence of Squaraine Thin Films: Spatial Homogeneity and Temperature Dependence
摘要： Temperature-dependent and spatially resolved photoluminescence (PL) spectroscopy is employed to probe the optical properties of spin-cast squaraine thin films annealed to different temperatures. SQIB, a squaraine derivative with donor-acceptor-donor configuration, crystallizes in monoclinic and orthorhombic structures at low and high temperatures, respectively. The former is characterized by an optical response typical for H-aggregates, while the latter shows J-type behavior. In temperature-dependent PL spectra, the two polymorphs are identified via their specific vibrational signature. Spatially resolved data taken with 5 μm resolution give insight into the homogeneity of the SQIB films. The high-temperature films are made of uniform J-type crystallites of 50–100 μm size, as also seen in polarization-dependent data. The low-temperature films comprise a mixture of grains with H- and J-character. Their specific spectral fingerprints superimpose to the overall emission response detected in the global PL spectra. The study demonstrates that the optical properties of SQIB thin films can be probed at the level of individual grains and systematically modified by thermal treatment.
关键词： squaraines,thin films,polarization,photoluminescence,J- and H-aggregates
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Interconnect Technology Conference (IITC) - Santa Clara, CA, USA (2018.6.4-2018.6.7)] 2018 IEEE International Interconnect Technology Conference (IITC) - Spray Plasma Processing of Barrier Films Deposited in Air for Improved stability of Flexible Electronic Devices
摘要： We report on submicron organosilicate barrier films produced rapidly in ambient by a scalable spray plasma process for improved solar cell stability. The plasma is at a sufficiently low temperature to be compatible with flexible electronic devices. The thickness of the barrier films is tunable and fully transparent over the visible spectrum. The morphology and density of the barrier are shown to improve with the addition of a fluorine-based precursor. Thin-film perovskite solar cells with submicron coatings exhibited significant improvements in stability when exposed to light, heat, and moisture. X-ray diffraction measurements performed while heating showed the barrier film dramatically slows the formation of PbI2. When deposited on a flexible substrate, the barrier films exhibit no signs of cracking or delamination after 10,000 bending cycles on a 127 μm substrate with a bending radius of 1 cm.
关键词： barrier films,spray plasma processing,flexible electronics,perovskite solar cells,stability
更新于2025-09-10 09:29:36