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Distinctive Optical Properties of Hierarchically Ordered Nanostructures Selfa??Assembled from Multiblock Copolymer/Nanoparticle Mixtures
摘要： Hybrid materials with hierarchical nanostructures are of great interest for their advanced functions. However, the effect of the formation of hierarchical nanostructures on properties is not well understood. Here, through combining dissipative particle dynamics simulation and the finite-difference time-domain method, the optical properties of hierarchically ordered nanostructures formed by mixtures of A(BC)n multiblock copolymers and nanoparticles (NPs) are investigated. A series of hierarchically ordered nanostructures with multiple small-length-scale hybrid domains are obtained from the self-assembly of A(BC)n/NP. An increase and blueshift in optical absorption are observed when the number of small-length-scale hybrid domains increases. The small-length-scale hybrid domains enhance light scattering, which consequently contributes to the improved optical performance. These findings can yield guidelines for designing hierarchically ordered functional nanocomposites with light-harvesting characteristics.
关键词： nanostructures,self-assembly,multiblock copolymers,nanoparticles,optical properties
更新于2025-09-23 15:19:57
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Nanoscale Perovskite-Sensitized Solar Cell Revisited: Is This Dye-Cell or Perovskite-Cell?
摘要： A general and straightforward way of preparing few nanometer-sized well-separated MAPbIxBr3-x perovskite photosensitizers on the surface of ~1 μm thick mesoporous TiO2 photoanode was suggested via a two-step sequential deposition of low-concentrated lead halides (0.10 ~ 0.30 M PbI2 or PbBr2) and methylammonium iodide/bromide (MAI/MABr). When those nanoscale MAPbIxBr3-x perovskites are incorporated as a photosensitizer in typical solid state dye-sensitized solar cells (ss-DSSCs), it could be verified clearly by the capacitance analysis that nano-particulate MAPbI3 perovskites are playing the same role as that of a typical dye sensitizer (MK-2 molecule) though their size, composition and structure are different.
关键词： perovskites,Impedance analysis,solid state dye-sensitized solar cells,sensitizers,nanostructures
更新于2025-09-23 15:19:57
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A sola??gel synthesis to prepare size and shape-controlled mesoporous nanostructures of binary (IIa??VI) metal oxides
摘要： A base-catalyzed sol–gel approach combined with a solvent-driven self-assembly process at low temperature is augmented to make manganese oxide (Mn3O4), copper oxide (CuO), and magnesium hydroxide (Mg(OH)2) nanostructures with size- and shape-controlled morphologies. Nanostructures of Mn3O4 with either hexagonal, irregular particle, or ribbon shape morphologies with an average diameter ranged from 100 to 200 nm have been prepared in four di?erent solvent types. In all morphologies of Mn3O4, the experimental XRD patterns have indexed the nanocrystal unit cell structure to triclinic. The hexagonal nanoparticles of Mn3O4 exhibit high mesoporocity with a BET surface area of 91.68 m2 g?1 and BJH desorption average pore diameter of ～28 nm. In the preparation of CuO nanostructures, highly nanoporous thin sheets have been produced in water and water/toluene solvent systems. The simulated XRD pattern matches the experimental XRD patterns of CuO nanostructures and indexes the nanocrystal unit cell structure to monoclinic. With the smallest desorption total pore volume of 0.09 cm3 g?1, CuO nanosheets have yielded the lowest BET surface area of 18.31 m2 g?1 and a BHJ desorption average pore diameter of ～16 nm. The sol of magnesium hydroxide nanocrystals produces highly nanoporous hexagonal nanoplates in water and water/toluene solvent systems. The wide angle powder XRD patterns show well-de?ned Bragg's peaks, indexing to a hexagonal unit cell structure. The hexagonal plates show a signi?cantly high BET surface area (72.31 m2 g?1), which is slightly lower than the surface area of Mn3O4 hexagonal nanoparticles. The non-template driven sol–gel synthesis process demonstrated herein provides a facile method to prepare highly mesoporous and nanoporous nanostructures of binary (II–VI) metal oxides and their hydroxide derivatives, enabling potential nanostructure platforms with high activities and selectivities for catalysis applications.
关键词： catalysis applications,size and shape-controlled morphologies,mesoporous nanostructures,binary (II–VI) metal oxides,sol–gel synthesis
更新于2025-09-23 15:19:57
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Metal Filled Nanostructured Silicon With Respect to Magnetic and Optical Properties
摘要： Within this work the utilization of nanostructured silicon as host material with various magnetic nanostructures is reviewed whereas the magnetic and optical properties of the gained composite systems are elucidated. The metal filling of the pores is mainly performed by electroless deposition or by electrodeposition which is discussed by means of some examples. Furthermore, two different types of porous silicon (PSi) morphology are used for the deposition procedure. On the one hand microporous silicon offering luminescence in the visible range is utilized as template material. It offers a branched morphology with a structure size between 2 and 5 nm. In this case not only the magnetic response is investigated but also the influence of the metal filling on the optical properties. On the other hand mesoporous and macroporous silicon in it’s low pore regime is employed which offers straight pores with diameters up to 90 nm. In this case the magnetic response strongly depends on the size, the geometry and the spatial distribution of the metal deposits within the pores. A crucial role plays also the morphology of the porous silicon, especially the distance between adjacent pores which is an important parameter regarding magnetic interactions.
关键词： magnetic nanostructures,porous silicon,magnetic properties,electrodeposition,luminescence
更新于2025-09-23 15:19:57
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Temperature Effect on Capillary Flow Dynamics in 1D Array of Open Nanotextured Microchannels Produced by Femtosecond Laser on Silicon
摘要： Capillary ?ow of water in an array of open nanotextured microgrooves fabricated by femtosecond laser processing of silicon is studied as a function of temperature using high-speed video recording. In a temperature range of 23–80°C, the produced wicking material provides extremely fast liquid ?ow with a maximum velocity of 37 cm/s in the initial spreading stage prior to visco-inertial regime. The capillary performance of the material enhances with increasing temperature in the inertial, visco-inertial, and partially in Washburn ?ow regimes. The classic universal Washburn’s regime is observed at all studied temperatures, giving the evidence of its universality at high temperatures as well. The obtained results are of great signi?cance for creating capillary materials for applications in cooling of electronics, energy harvesting, enhancing the critical heat ?ux of industrial boilers, and Maisotsenko cycle technologies.
关键词： Maisotsenko cycle,cooling of electronics,silicon,open capillary microchannels,microstructures,nanostructures,femtosecond laser processing,capillary flow
更新于2025-09-23 15:19:57
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Prospects of Coupled Organica??Inorganic Nanostructures for Charge and Energy Transfer Applications
摘要： We review the field of organic-inorganic nanocomposites with a focus on materials that exhibit a significant degree of electronic coupling across the hybrid interface. These nanocomposites undergo a variety of charge and energy transfer processes, enabling optoelectronic applications in devices which exploit singlet fission, triplet energy harvesting, photon upconversion or hot charge carrier transfer. We discuss the physical chemistry of the most common organic and inorganic components. Based on those we derive synthesis and assembly strategies and design criteria on material and device level with a focus on photovoltaics, spin memories or optical upconverters. We conclude that future research in the field should be directed towards an improved understanding of the binding motif and molecular orientation at the hybrid interface.
关键词： Inorganic Nanostructures,Self-Assembly,Organic π-Systems,Optoelectronic Devices,Plasmonics
更新于2025-09-23 15:19:57
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Facile synthesis of Nd2Sn2O7-SnO2 nanostructures by novel and environment-friendly approach for the photodegradation and removal of organic pollutants in water
摘要： A simple and clean synthesis for Nd2Sn2O7-SnO2 nanocomposites as high-efficiency visible-light responsive photocatalyst is described applying extract of pineapple, for the first time. As novel and non-toxic biofuel, extract of pineapple, is employed to fabricate Nd2Sn2O7-SnO2 nanocomposites through an environment-friendly procedure. The findings denote that the applied biofuel can play a meaningful role as capping agent during preparation of Nd2Sn2O7-SnO2 nanocomposites. Depending on the applied dosage of pineapple extract as well as time for fabrication, the grain size, photocatalytic yield and morphology of Nd2Sn2O7-SnO2 structures changed. A suite of identification methods like XRD, TEM, EDS, DRS, BET and FESEM are utilized for investigation of the produced Nd2Sn2O7-SnO2 nanocomposites. Nd2Sn2O7-SnO2 structures are utilized as visible-light responsive photocatalyst to degrade the rhodamine B and eosin Y contaminants. The produced Nd2Sn2O7-SnO2 nanocomposites have been found to be very effective as visible-light responsive photocatalyst to degrade contaminants which may bring to environmental pollution.
关键词： Photocatalytic degradation,Nd2Sn2O7-SnO2,Nanostructures,Green synthesis
更新于2025-09-23 15:19:57
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Engineering Efficient Photon Upconversion in Semiconductor Heterostructures
摘要： Photon upconversion is a photophysical process in which two low-energy photons are converted into one high-energy photon. Photon upconversion has broad appeal for a range of applications from biomedical imaging and targeted drug-release to solar energy harvesting. Current upconversion nanosystems, including lanthanide-doped nanocrystals and triplet-triplet annihilation (TTA) molecules, have achieved upconversion quantum yields of order 10-30%. However, the performance of these materials is hampered by inherently narrow absorption cross-sections and fixed energy levels originating in atomic, ionic, or molecular states. Semiconductors, on the other hand, have inherently wide absorption cross-sections. Moreover, recent advances enable the synthesis of colloidal semiconductor nanoparticles with complex heterostructures that can control band alignments and tune optical properties. We synthesize and characterize a three-component heterostructure that successfully upconverts photons under continuous-wave (CW) illumination and solar-relevant photon fluxes. The heterostructure is composed of two cadmium selenide (CdSe) quantum dots (QDs), an absorber and emitter, spatially separated by a cadmium sulfide (CdS) nanorod (NR). We demonstrate that the principles of semiconductor heterostructure engineering can be applied to engineer improved upconversion efficiency. We first eliminate electron trap-states near the surface of the absorbing QD and then tailor the bandgap of the NR such that charge carriers are funneled to the emitting QD. When combined, these two changes result in a 100-fold improvement in photon upconversion performance.
关键词： solar energy,semiconductors,upconversion,coupled quantum dots,nanostructures,core/rod/emitter
更新于2025-09-23 15:19:57
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Thermoelectric Properties of (100) Oriented Silicon and Nickel Silicide Nanocomposite Films Grown on Si on Insulator and Si on Quartz Glass Substrates
摘要： We have grown (100) oriented composite films of Si and Ni silicide nanocrystals (Ni–Si NC film) on substrates of Si on insulator (SOI) and Si on quartz glass (SOQ). Owing to improvement of carrier transport properties and reduction of the thermal conductivity in the oriented films, they have higher dimensionless figures of merit, ZT of 0.22–0.42 for p-type Ni–Si NC film and 0.08–0.13 for n-type Ni–Si NC film than that of bulk Si (ZT < 0.01) at 30°C. The ZT values of p-type and n-type Ni–Si NC films were increased to 0.65 and 0.40 at 500°C, respectively.
关键词： silicon based thermoelectric materials,nanocomposite films,nickel silicide nanocrystals,silicon nanostructures,phonon scattering
更新于2025-09-19 17:15:36
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Au Nanobottles with Synthetically Tunable Overall and Opening Sizes for Chemo-Photothermal Combined Therapy
摘要： Highly asymmetric Au nanostructures, such as split Au nanorings and Au nanocups, exhibit attractive plasmonic properties due to their asymmetric geometries. To facilitate their plasmonic applications, effective and facile synthetic methods for producing asymmetric Au nanostructures with controllable sizes and uniform shapes are highly desirable. Herein we report on an approach for the synthesis of largely asymmetric colloidal Au nanobottles with synthetically tunable overall and opening sizes. Au nanobottles with overall sizes in the range of ~100–230 nm are obtained through the sacrificial templating with differently sized PbS nanooctahedra. The opening sizes of the produced Au nanobottles can be tailored from ~10 to ~120 nm by either adjusting the Au/PbS molar ratio in the growth process or controlling the oxidation degree. The achieved size tunability allows the plasmon resonance wavelength of the Au nanobottles to be varied in the range of ~600–900 nm. Our uniform Au nanobottles, which possess controllable sizes, large cavity volumes and tunable plasmon resonance wavelengths in the visible to near-infrared range, have been further applied for anticancer drug delivery and photothermal therapy. The effects of the surface coating and opening size of the Au nanobottles on the drug encapsulation efficiency and initial burst drug release are systemically evaluated. A high doxorubicin encapsulation efficiency and low initial burst drug release are realized with the dense silica-coated Au nanobottles having the opening size of 44 nm. In addition, chemo-photothermal combined therapy has been demonstrated with the doxorubicin-loaded Au nanobottles. Our results will be helpful for the design of the Au nanobottles with different sizes and plasmonic properties as well as ample opportunities for exploring various plasmon-enabled applications out of the Au nanobottles.
关键词： asymmetric metal nanostructures,plasmon resonance,gold nanobottles,magnetic plasmon resonance,photothermal therapy,drug delivery
更新于2025-09-19 17:15:36