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CH<sub>2</sub>O Adsorption on M (M = Li, Mg and Al) Atom Deposited ZnO Nano-Cage: DFT Study
摘要： The structural and electronic properties of Li, Mg and Al deposited ZnO nano-cages and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory (DFT) computations. To understand the behavior of the adsorbed CH2O molecule on the ZnO nano-cage, results of DFT calculations of the M-deposited nano-cages (M=Li, Mg and Al), as well as complex systems consisting of the adsorbed CH2O molecule on M-deposited ZnO nano-cage were reported. The results presented include adsorption energies, bond lengths, electronic configurations, density of states and molecular orbitals. It was found that, the most energetically stable adsorption configurations of CH2O molecule on the bare ZnO leads to 12% dilation in C=O bond length of CH2O and 14% decrease in HOMO-LUMO gap of ZnO cluster. The most energetically stable adsorption configurations of CH2O molecule on Li, Mg and Al-deposited ZnO lead to 4%, 4% and 11% dilation in C=O bond length of CH2O and -0.66, -45 and , +66% change in HOMO-LUMO gap of ZnO nano cages, respectively. The interaction between CH2O with bare ZnO and M-deposited ZnO nano-cages is attributed to charge transfer mechanism. These results may be meaningful for CH2O degradation and detection.
关键词： ZnO,Adsorption,nanomaterials,Formaldehyde,DFT
更新于2025-09-23 15:21:21
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Improved Models for Metallic Nanoparticle Cores From Atomic Pair Distribution Function (PDF) Analysis
摘要： X-ray atomic pair distribution functions (PDFs) were collected from a range of canonical metallic nanomaterials, both elemental and alloyed, prepared using different synthesis methods and exhibiting drastically different morphological properties. Widely applied shape-tuned attenuated crystal (AC) fcc models proved inadequate, yielding structured, coherent, and correlated fit residuals. However, equally simple discrete cluster models could account for the largest amplitude features in these difference signals. A hypothesis testing based approach to nanoparticle structure modelling systematically ruled out effects from crystallite size, composition, shape, and surface faceting as primary factors contributing to the AC misfit. On the other hand, decahedrally twinned cluster cores were found to be the origin of the AC structure misfits for a majority of the nanomaterials reported here. It is further motivated that the PDF can readily differentiate between the arrangement of domains in these multiply-twinned motifs. Most of the nanomaterials surveyed also fall within the sub-5 nm size regime where traditional electron microscopy cannot easily detect and quantify domain structures, with sampling representative of the average nanocrystal synthesized. The results demonstrate that PDF analysis is a powerful method for understanding internal atomic interfaces in small noble metallic nanomaterials. Such core cluster models, easily built algorithmically, should serve as starting structures for more advanced models able to capture atomic positional disorder, ligand induced or otherwise, near nanocrystal surfaces.
关键词： decahedrally twinned cluster cores,PDF analysis,metallic nanomaterials,nanocrystal surfaces,X-ray atomic pair distribution functions
更新于2025-09-23 15:21:21
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[Biologically-Inspired Systems] Stimuli-Responsive Dewetting/Wetting Smart Surfaces and Interfaces Volume 11 || Photo-Responsive Superwetting Surface
摘要： Photo-responsive surfaces, especially for the photo-responsive superwetting surface, have aroused great interests in smart control devices for a few years due to their remote control and selectivity. This chapter focuses on the photo-responsive wettability on the superwetting surface and their typical applications, particularly on switchable wettability on photo-responsive surfaces and their applications such as droplet actuation, adhesion control, liquid printing and oil-water separation. Finally, our personal point of the prospects and challenges of the photo-responsive wettability surfaces are presented.
关键词： Photo-responsive surface,Separation,Nanomaterials,Liquid actuation,Superwetting
更新于2025-09-23 15:21:21
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Treatment of graphene films in the early and late afterglows of N2 plasmas: comparison of the defect generation and N-incorporation dynamics
摘要： Graphene films grown on copper substrate by chemical vapor deposition were exposed to the flowing afterglow of a reduced-pressure N2 plasma sustained by microwave electromagnetic fields (surface-wave plasma). Two set of conditions were examined by controlling the gas flow rate: the late afterglow (LA) characterized by high number densities of reactive N atoms and the early afterglow (EA) in which significant populations of metastable N2(A) states and positive ions (N2+ and N4+) coexist with plasma-generated N atoms. LA treatments of graphene films show monotonous and steady incorporation of nitrogen atoms along with very low damage. However, given the very mild LA treatment conditions, a large part of the N atoms remains weakly bonded to the graphene surface; a feature ascribed to the plasma-induced functionalization of airborne hydrocarbon contaminants. In such conditions, graphitic inclusion of plasma-generated N atoms is limited to native defect sites. On the other hand, the presence of highly energetic species in the EA induces significant damage combined with much higher N-incorporation. Detailed Raman analysis of EA-treated samples further reveals a transition from vacancy-type defects to much larger multi-vacancies with increasing treatment time. This complete set of data indicates that, through a judicious control of the populations of reactive N atoms, metastable N2(A) states, and positive ions (N2+ and N4+), the flowing afterglow of microwave N2 plasmas represents a highly promising tool for precise, post-growth tuning of the defect generation and N-incorporation dynamics in graphene films.
关键词： Microwave plasmas,Plasma-graphene interactions,Flowing afterglows,Plasma-induced modification of materials and nanomaterials
更新于2025-09-23 15:21:21
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A universal growth strategy for DNA-programmed quantum dots on graphene oxide surfaces
摘要： The emerging materials of semiconductor quantum dots/graphene oxide (QDs/GO) hybrid composites have recently attracted intensive attention in materials science and technology due to their potential applications in electronic and photonic devices. Here, a simple and universal strategy to produce DNA-programmed semiconductor quantum dots/graphene oxide (QDs/GO) hybrid composites with controllable sizes, shapes, compositions, and surface properties is reported. This proof-of-concept work successfully demonstrates the use of sulfhydryl modi?ed single-stranded DNA (S-ssDNA) as a ‘universal glue’ which can adsorb onto GO easily and provide the growth sites to synthesize CdS QDs, CdSe QDs, CdTe QDs and CdTeSe QDs with distinctive sizes, shapes and properties. Also, adapting this method, other graphene oxide-based hybrid materials which are easily synthesized in aqueous solution, including oxides, core–shell structure QDs and metal nanocrystals, would be possible. This method provided a universal strategy for the synthesis and functional realization of graphene -based nanomaterials.
关键词： quantum dots/graphene oxide,DNA,two-dimensional materials,graphene -based nanomaterials
更新于2025-09-23 15:21:01
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Block Copolymer Derived Vertically Coupled Plasmonic Arrays for Surface-Enhanced Raman Spectroscopy
摘要： A surface-enhanced Raman spectroscopy sensing template consisting of gold-covered nanopillars is developed. The plasmonic slab consists of a perforated gold film at the base of the nanopillars and a Babinet complementary dot array on top of the pillars. The nanopillars were fabricated by the incorporation of an iron salt precursor into a self-assembled block copolymer thin film and subsequent reactive ion etching. The preparation is easy, scalable, and cost-effective. We report on the increase in surface-enhanced Raman scattering efficiency for smaller pillar heights and stronger coupling between the dot array and perforated gold film with average enhancement factors as high as 107. In addition, the block copolymer-derived templates show an excellent relative standard deviation of 8% in the measurement of the Raman intensity. Finite difference time domain simulations were performed to investigate the nature of the electromagnetic near-field enhancement and to identify plasmonic hot spots.
关键词： block copolymer lithography,finite difference time domain simulation,SERS uniformity,plasmonic nanomaterials,surface-enhanced Raman spectroscopy,nanofabrication,4-aminothiophenol
更新于2025-09-23 15:21:01
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Chiral Helical Polymer Nanomaterials with Tunable Morphology: Prepared with Chiral Solvent To Induce Helix-Sense-Selective Precipitation Polymerization
摘要： We report an unprecedented strategy for using achiral monomer to construct chiral helical polymer nanomaterials with tunable morphology—helix-sense-selective precipitation polymerization induced by a chiral solvent (HSSPP-CS). CHCl3, chiral α-pinene, and an alkanol were employed to constitute a solvent mixture for performing HSSPP-CS. (R)- or (S)-α-pinene worked as chiral source and transferred its chirality to the resulting helical polyacetylenes derived from achiral monomer in the course of polymerization, thereby forming chiral helical polymers and endowing the nanomaterials thereof with optical activity. Simply changing solvent composition provided chiral polymer products varying in morphology from fibrous to rod-like and finally to spherical morphology. This is the first report dealing with chirality transfer from chiral solvent to induce helix-sense-selective precipitation polymerizations. The study establishes a straightforward and effective alternative for making use of achiral monomers to construct chiral helical polymer nanomaterials with diverse morphology.
关键词： tunable morphology,chiral solvent,achiral monomer,chiral helical polymer nanomaterials,helix-sense-selective precipitation polymerization
更新于2025-09-23 15:21:01
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Three Dimensional Imaging of Biological Samples and Nano-materials Using Soft X-ray Microscopy
摘要： The soft X-ray Microscopy beamline BL07W at National Synchrotron Radiation Laboratory is devoted to cryo nano-tomography for biological applications in the water window (284 - 530 eV) and for imaging of nanomaterials from 200 to 2500 eV. An ellipsoidal capillary used as condense to focus monochromatic light onto the sample. Two Ni zone plate (ZP) lenses made by Zeiss with 40 nm and 25 nm outer most zone widths, respectively, are available, giving spatial resolution in 2D of down to 40 nm and 30 nm, respectively. Hydrated biological specimens had been imaged in the water window photon energy range without chemical fixation, dehydration, chemical staining and physical sectioning. In addition, other applications such as nanomaterials imaging had been demonstrated.
关键词： cryo nano-tomography,Soft X-ray Microscopy,nanomaterials imaging,water window
更新于2025-09-23 15:21:01
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Challenges and opportunities for nanomaterials in spectral splitting for high-performance hybrid solar photovoltaic-thermal applications: A review
摘要： Hybrid photovoltaic-thermal (PV-T) collectors, which are capable of cogenerating useful thermal energy and electricity from the same aperture area, have a significantly higher overall efficiency and ability to displace emissions compared to independent, separate photovoltaic panels, solar thermal collectors or combinations thereof. Spectral splitting has emerged as a promising route towards next-generation high-performance PV-T collectors, and nanotechnology plays an important role in meeting the optical and thermal requirements of advanced spectral splitting PV-T collector designs. This paper presents a comprehensive review of spectral splitting technologies based on nanomaterials for PV-T applications. Emerging nanomaterials (nanofluids, nanofilms and nanowires) suitable for achieving spectral splitting based on reflection, diffraction, refraction and/or absorption approaches in PV-T collectors are presented, along with the associated challenges and opportunities of these design approaches. The requirements from such materials in terms of optical properties, thermal properties, stability and cost are discussed with the aim of guiding future research and innovation, and developing this technology towards practical application. Nanofluids and nanofilms are currently the most common nanomaterials used for spectral splitting, with significant progress made in recent years in the development of these materials. Nevertheless, there still remains a considerable gap between the optical properties of currently-available filters and the desired properties of ideal filters. Aiming to instruct and guide the future development of filter materials, a simple generalized method is further proposed in this paper to identify optimal filters and efficiency limits of spectral splitting PV-T systems for different scenarios. It is found that the optimal filter of a spectral splitting PV-T system is highly sensitive to the value of thermal energy relative to that of electricity, which therefore depends strongly on the application and location. The efficiency limit of spectral splitting PV-T collectors is significantly higher than that of standalone PV panels. The stability of nanomaterial filters remains a critical challenge for their long-term employment and also for high-temperature operation in practical applications.
关键词： Nanofilms,Spectral splitting,Nanomaterials,Thermal properties,Stability,Nanofluids,Optical properties,Cost,Nanowires,Hybrid photovoltaic-thermal (PV-T) collectors
更新于2025-09-23 15:21:01
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Peculiarities of using nanomaterials based on SiO <sub/>2</sub> -SnO <sub/>2-</sub> In <sub/>2</sub> O <sub/>3</sub> as sensitive elements of vacuum sensors
摘要： Experimental data on the use of nanomaterials based on SiO2-SnO2-In2O3 as sensitive elements of vacuum sensors are presented. It is shown that the sensory response of a three-component system under consideration is determined by the mass fraction of indium oxide. It was determined that depending on the content of In2O3 the nanomaterials under study can be characterized by a decrease and an increase in resistance when the pressure is reduced lower than atmospheric one. The mechanisms that potentially correspond to the observed phenomenon are considered.
关键词： nanomaterials,indium oxide,SiO2-SnO2-In2O3,vacuum sensors,sensitive elements
更新于2025-09-23 15:21:01