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Mechanism Behind the Easy Exfoliation of Ga <sub/>2</sub> O <sub/>3</sub> Ultra-Thin Film Along (100) Surface
摘要： The transparent wide band gap semiconductor β-Ga2O3 has gained wide attention due to its suitability to a wide range of applications. Despite not being a van der Waals material and having highly strong ionic bonding, the material can be mechanically cleaved and exfoliated easily along favorable surfaces to make ultra-thin layers and used in device fabrications. One of the interesting properties of this material is that thin layers preserve the pristine bulk-like electronic properties, which makes it even more promising for applications in power devices. However, very little is known about the mechanism why such ultra-thin film or even single bilayer exfoliation is favorable from the bulk. In this letter, we have explained the mechanism of such phenomenon by detailed analyses of different types of Ga–O bonding character. The protocol of methodology used and developed in this study can be utilized in general to understand bond breaking and forming of other complex materials as well. This understanding will give us a better control to fabricate thin film 2D devices.
关键词： density functional theory,bond energy,computational physics,2D Ga2O3,easy exfoliation,surface energy
更新于2025-09-23 15:23:52
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A turn-on fluorescent probe for vitamin C based on the use of a silicon/CoOOH nanoparticle system
摘要： The authors describe a fluorometric method for the turn-on determination of vitamin C (ascorbic acid). The blue fluorescence of silicon nanoparticles (SiNPs; with excitation/emission maxima at 350/450 nm) is found to be quenched by CoOOH nanoparticles (NPs). In the presence of vitamin C, the CoOOH NPs are decomposed by a redox reaction between the diol group of vitamin C and CoOOH NPs. As a result, fluorescence recovers. On the basis of this finding, a fluorometric method was designed for the turn-on detection of vitamin C. Under optimal conditions, the method has a low detection limit (0.47 μM) and a linear response in the 0.5 μM to 20 μM a concentration range. It was successfully applied to the determination of vitamin C in spiked red grape and orange juice, and in vitamin C tablets.
关键词： Fluorescence Bturn-on^ strategy,Cobalt oxyhydroxide nanoparticles,Fluorometry,Stern-Volmer plot,Surface energy transfer,Redox reaction,Inner filter effect,Quenching,Silicon nanoparticles
更新于2025-09-23 15:23:52
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Preparation and characterization of UV-curable fluorine-silicon block urethane acrylates for application in release films
摘要： A series of fluorine-silicon block urethane acrylates (PSi-FMPG-IPDI-HEMA) were synthesized from hydroxypropyl-terminated polysiloxane (PSi), newly-prepared fluorodiol (FMPG), isophorone diisocyanate (IPDI) and hydroxyethyl methacrylate (HEMA). Their molecular structures were characterized by Fourier transform infrared and gel permeation chromatography. The compatibility of the oligomers with HFMA was validated using UV–vis transmittance analysis. The thermal stability, water and chemical resistance, contact angles and anti-adhesive performance of the films were measured. It was found all the films had good thermal properties, and excellent water and chemical resistance. The FMPG content affected the surface energy and anti-adhesive performance of the films. The films with more FMPG presented lower surface energy, lower peel strength, and higher residual adhesion. More importantly, the release films designed based on the fluorine-silicon block urethane acrylates had tremendous application potential.
关键词： Anti-adhesive performance,Surface energy,Fluorine-silicon block urethane acrylates,Thermal stability
更新于2025-09-23 15:22:29
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Improvement of Exciton Collection and Light-Harvesting Range in Ternary Blend Polymer Solar Cells Based on Two Non-Fullerene Acceptors
摘要： A non‐fullerene molecule named Y6 was incorporated into a binary blend of PBDB‐T and IT‐M to further enhance photon harvesting in the near‐infrared (near‐IR) region. Compared with PBDB‐T/IT‐M binary blend devices, PBDB‐T/IT‐M/Y6 ternary blend devices exhibited an improved short‐circuit current density (JSC) from 15.34 to 19.09 mA cm?2. As a result, the power conversion efficiency (PCE) increased from 10.65% to 12.50%. With an increasing weight ratio of Y6, the external quantum efficiency (EQE) was enhanced at around 825 nm, which is ascribed to the absorption of Y6. At the same time, EQE was also enhanced at around 600–700 nm, which is ascribed to the absorption of IT‐M, although the optical absorption intensity of IT‐M decreased with increasing weight ratio of Y6. This is because of the efficient energy transfer from IT‐M to Y6, which can collect the IT‐M exciton lost in the PBDB‐T/IT‐M binary blend. Interestingly, the EQE spectra of PBDB‐T/IT‐M/Y6 ternary blend devices were not only increased but also red‐shifted in the near‐IR region with increasing weight ratio of Y6. This finding suggests that the absorption spectrum of Y6 is dependent on the weight ratio of Y6, which is probably due to different aggregation states depending on the weight ratio. This aggregate property of Y6 was also studied in terms of surface energy.
关键词： non‐fullerene,exciton harvesting,surface energy,ternary blend solar cells,energy transfer
更新于2025-09-19 17:13:59
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Self‐Assembly of Nanoparticle‐Spiked Pillar Arrays for Plasmonic Biosensing
摘要： Plasmonic biosensors have demonstrated superior performance in detecting various biomolecules with high sensitivity through simple assays. Scaled-up, reproducible chip production with a high density of hotspots in a large area has been technically challenging, limiting the commercialization and clinical translation of these biosensors. A new fabrication method for 3D plasmonic nanostructures with a high density, large volume of hotspots and therefore inherently improved detection capabilities is developed. Specifically, Au nanoparticle-spiked Au nanopillar arrays are prepared by utilizing enhanced surface diffusion of adsorbed Au atoms on a slippery Au nanopillar arrays through a simple vacuum process. This process enables the direct formation of a high density of spherical Au nanoparticles on the 1 nm-thick dielectric coated Au nanopillar arrays without high-temperature annealing, which results in multiple plasmonic coupling, and thereby large effective volume of hotspots in 3D spaces. The plasmonic nanostructures show signal enhancements over 8.3 × 108-fold for surface-enhanced Raman spectroscopy and over 2.7 × 102-fold for plasmon-enhanced fluorescence. The 3D plasmonic chip is used to detect avian influenza-associated antibodies at 100 times higher sensitivity compared with unstructured Au substrates for plasmon-enhanced fluorescence detection. Such a simple and scalable fabrication of highly sensitive 3D plasmonic nanostructures provides new opportunities to broaden plasmon-enhanced sensing applications.
关键词： surface diffusion,plasmonic biosensors,spherical metal nanoparticles,3D nanostructures,surface energy
更新于2025-09-19 17:13:59
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Wetting translucency of graphene on plasmonic nanohole arrays
摘要： Graphene- a carbon allotrope with atoms arranged in monolayer two-dimensional hexagonal lattice- exhibits wide range of applications in batteries, supercapacitors, solar cells, biosensing, light-emitting diodes, semi-conductors, materials composites, and coatings to name a few. Significant progress has been made to understand the electronic, mechanical, and optical characteristics of graphene. However, the wettability of graphene, which is important for surface modification and thermal/fluidic properties, is still not well understood. The level of transparency to van der Waals forces, chemical bonds, and electrostatic interactions between atoms and molecules on two sides of graphene single layer is partially known. Static contact angle between the edge of sessile drop and functionalized surface provides surface tension value based on Owens-Wendt model and is important for wettability studies. In this work, we investigate the surface energy of glass, silicon wafer, and plasmonic nano-hole arrays (Silver, Polymer and Gold) suspended with CVD grown and transferred single layer of graphene. Our results showed that the underlying substrate does affect the wettability of graphene monolayer due to van der Waal hydrocarbon, metal-carbide, and silica-carbon bonding which tends to provide deeper understanding of the wetting dynamics. This study elucidates the mechanism of wetting translucency of graphene on plasmonic nanohole arrays.
关键词： Plasmonic nanohole array,contact angle,graphene,surface energy
更新于2025-09-12 10:27:22
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Validation of Fine Resolution Land-Surface Energy Fluxes Derived with Combined Sentinel-2 and Sentinel-3 Observations
摘要： A methodology for deriving land-surface energy fluxes estimated with the use of Sentinel-2 and Sentinel-3 observations is validated in a savannah landscape in central Spain. The fluxes are derived at two spatial resolution: fine (20m) and coarse (around 1km). At both resolutions the thermal observations from Sea and Land Surface Temperature Radiometer (SLSTR) on Sentinel-3 and optical observations from Multi-Spectral Instrument (MSI) on Sentinel-2 are used within a Two-Source Energy Balance (TSEB) modelling scheme. For the fine resolution estimates, the thermal observations acquired by SLSTR at around 1km resolution are sharpened using high-resolution (20m) optical observations taken by MSI and a machine learning algorithm. The results indicate that it is possible to derive fluxes with similar accuracy at both spatial scales, while obtaining more detailed separation of fluxes originating from individual landscape features at the fine scale.
关键词： machine learning,Sentinel-2,land-surface energy fluxes,Sentinel-3,thermal sharpening
更新于2025-09-10 09:29:36
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[Micro/Nano Technologies] Micro and Nano Fabrication Technology Volume 1 || Fabrication of Metallic Nanodot Arrays
摘要： Metal nanodot arrays exhibit unique optical characteristics, and they are expected to find widespread applications in biosensors and various optical devices. In this section, simple and efficient manufacturing processes are introduced for metal nanodot arrays. These processes are based on the combination of thin metal film coatings deposited on substrates and thermal dewetting. The first process discussed herein is a conventional thermal dewetting method. With this method, it is shown that the average dot diameter can be controlled based on the chosen process conditions. The second process is based on the use of grid patterning on coated metal films. This process can allow fabrication of nanodot arrays with uniform dot diameters and achieve highly ordered alignment of dots. The third process generates a metal nanodot array based on a self-organization manner on a nanogrid-patterned substrate. It constitutes a high-productivity process based on the transfer of the metal nanodot array to an adhesive film. The basic mechanisms underlying these processes are discussed herein.
关键词： Productivity,Metal coating,Dot transfer,Surface energy,Metal nanoparticles,Agglomeration,Nano plastic forming,Optical characteristics,Grid patterning,Self-organization,Biosensors,Thermal dewetting
更新于2025-09-10 09:29:36
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Impact of Land Cover Change Induced by a Fire Event on the Surface Energy Fluxes Derived from Remote Sensing
摘要： Forest fires affect the natural cycle of the vegetation, and the structure and functioning of ecosystems. As a consequence of defoliation and vegetation mortality, surface energy flux patterns can suffer variations. Remote sensing techniques together with surface energy balance modeling offer the opportunity to explore these changes. In this paper we focus on a Mediterranean forest ecosystem. A fire event occurred in 2001 in Almodóvar del Pinar (Spain) affecting a pine and shrub area. A two-source energy balance approach was applied to a set of Landsat 5-TM and Landsat 7-EMT+ images to estimate the surface fluxes in the area. Three post-fire periods were analyzed, six, seven, nine, and 11 years after the fire event. Results showed the regeneration of the shrub area in 6–7 years, in contrast to the pine area, where an important decrease in evapotranspiration, around 1 mm·day?1, remained. Differences in evapotranspiration were mitigated nine and 11 years after the fire in the pine area, whereas significant deviations in the rest of the terms of the energy balance equation were still observed. The combined effect of changes in the vegetation structure and surface variables, such as land surface temperature, albedo, or vegetation coverage, is responsible for these variations in the surface energy flux patterns.
关键词： surface energy fluxes,Landsat,forest fire,land cover change,evapotranspiration
更新于2025-09-04 15:30:14
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Simulation and visualization of crystal shapes and interfaces
摘要： Nature often arranges atoms in the shape of perfect crystals, but sometimes she creates defects and multiple domains. The optimal crystal shape at zero kelvin can be found via the Wul? construction, which can be only be carried out analytically for those trivial cases where next nearest neighbour interactions can be neglected. For our system of interest - videlicit the HCP non-Bravais case, numerical simulation is needed. This system is of relevance because we are modeling helium crystals. We have modeled two adjacent crystallites with di?erent orientations in contact creating twist or tilt grain boundaries, and calculated the surface energy of the interface. Experience gained from several aspects of this project have a wider applications, including the condensed matter simulation application to sample construction for multi-domain crystals, and a visualization one for representation in the presence of grain boundaries. The optimization of sample shapes into their groundstates is also related to wavefront optimization in multimirror telescopes.
关键词： surface energy,interfaces,HCP lattice,Wul? construction,crystal shapes,grain boundaries
更新于2025-09-04 15:30:14