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Growth and Chemical Modification of Silicon Nanostructures Templated in Molecule Corrals: Parallels with the Surface Chemistry of Single Crystalline Silicon
摘要： Molecule corrals having diameters of 30 – 50 nm were created on highly oriented pyrolytic graphite (HOPG) using cesium ion bombardment. The molecule corrals were used as templates to grow silicon nanostructures by physical vapor deposition (PVD). The nanostructures could be grown with control over geometry (rings and mesas), and size distribution. In addition, transmission electron microscopy (TEM) results suggest that the silicon nanostructures are most likely polycrystalline. The chemical modification of these silicon nanostructures with nitrobenzene was compared to that of clean and hydrogen-terminated single crystalline silicon. X-ray photoelectron spectroscopy (XPS) of the modified nanostructures showed peaks located at 398.9 eV, 400.4 eV, and 402.1 eV for the N 1s region, which are consistent with those observed on a Si(100) single crystal. The chemical modification was further characterized by the presence of nitrogen-containing peaks in TOF-SIMS spectra. We conclude that the reaction of nitrobenzene on silicon nanostructures provides evidence that the reactivity of the nanostructures is similar to that of hydrogen-terminated Si(111) and Si(100).
关键词： molecule corrals,functionalized silicon,silicon nanoparticle,chemical modification,template,surface modification
更新于2025-09-19 17:15:36
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Surface plasmon-polariton: a novel initiation way for azide alkyne cycloaddition
摘要： Plasmon-catalysis has recently generated tremendous interest in the field of modern chemistry. Application of plasmon introduces the principally new stimuli for the activation of organic reactions, keeping the optical energy concentrated in the vicinity of plasmonic structure, creating optical near-field enhancement as well as hot electrons injection. In this work, for the first time, we presented a new way for the initiation of the azide-alkyne cycloaddition (AAC) using the surface plasmon-polariton wave, supported by the gold grating. With this concept in hand, the plasmon-active gold grating was functionalized with the 4-ethynylbenzenediazonium compound. Then, surface grafted 4-ethynylphenyl groups were plasmon activated and clicked with 4-azidobenzoic acid. Additional experiments excluded the potential effect of photon, heating, and metal impurities confirmed the key role of surface plasmon-polariton AAC activation. For investigation of plasmon-induced AAC mechanism, 4-azidophenyl groups (instead of 4-ethynylphenyl groups) were also grafted to the grating surface. Further careful evaluation of reaction kinetics demonstrates that AAC reaction rate is significantly higher in the case of acetylene activation than in the case of azide activation.
关键词： gold grating,azide alkyne cycloaddition,surface modification,plasmon catalysis,surface plasmon-polariton
更新于2025-09-19 17:15:36
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Atomic layer deposition for membrane interface engineering
摘要： In many applications, interfaces govern the performance of membranes. Structure, chemistry, electrostatics, and other properties of interfaces can dominate the selectivity, flux, fouling resistance, and other critical aspects of membrane functionality. Control over membrane interfacial properties, therefore, is a powerful means of tailoring performance. In this Minireview, we discuss the application of atomic layer deposition (ALD) and related techniques in the design of novel membrane interfaces. We discuss recent literature in which ALD is used to (1) modify the surface chemistry and interfacial properties of membranes, (2) tailor the pore sizes and separation characteristics of membranes, and (3) enable novel advanced functional membranes.
关键词： membrane interface engineering,pore size tuning,surface modification,functional membranes,atomic layer deposition
更新于2025-09-19 17:15:36
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How to Grow Fully (100) Oriented SiC/Si/SiC/Si Multi-Stack
摘要： This paper reports on the successful elaboration of fully (100) oriented SiC/Si/SiC/Si multi-stack using chemical vapor deposition. Si(100) heteroepitaxy on 3C-SiC(100) is identified as the critical step which is solved by pulse insertion of precursors during cooling. It lead to the roughening of the 3C-SiC surface which in turn lead to the quasi-exclusive nucleation of (100) oriented islands at the expanse of (110) ones. Subsequent Si epitaxy on such modified surface allows growing fully (100) oriented Si layer, as confirmed by structural characterization of the layers. The 3C-SiC grown on top of such Si(100) layer is again of (100) orientation, forming thus a fully (100) oriented stack. Due to the high lattice mismatch, each interface of the stack is characterized by a high density of crystalline defects which are shown to recombine along with thickness. Antiphase domains present inside the 3C-SiC seed are shown to have no detrimental influence on the Si layer quality. Without the surface modification step, the Si layers grown on 3C-SiC are always polycrystalline with a mixture of (110) and (100) orientations.
关键词： CVD,3C-SiC,surface modification,multilayers,Si heteroepitaxy
更新于2025-09-19 17:15:36
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Photo-oxidative degradation of methylammonium lead iodide perovskite: mechanism and protection
摘要： Although the power conversion efficiency of perovskite solar cells has exceeded 23%, the poor ambient stability of organic–inorganic halide perovskites poses a challenge for their commercialization. Comprehensive understanding of the underlying degradation mechanisms is a crucial step to seek approaches that can effectively suppress the degradation of perovskites. Herein, on the basis of extensive first-principles calculations, a three-step photo-oxidative degradation mechanism of MAPbI3 at the atomic level is revealed. We find that, in a dry ambient environment, the photo-generated superoxide anions (O2?) first lead to fast surface oxidation. However, further oxidation of the perovskite interior is hindered by the solid oxidation product. The fresh water produced in surface oxidation leads to the hydration of the inner perovskite and eventual breakage of the MAPbI3 lattice. We devise a practical strategy for protecting MAPbI3 from photo-induced decomposition by anchoring hydrophobic 2-(4-fluorophenyl)propan-2-amine on the surface of MAPbI3. The surface modification significantly retards the photo-induced decomposition.
关键词： superoxide anions,photo-oxidative degradation,surface modification,perovskite solar cells,MAPbI3,stability
更新于2025-09-19 17:15:36
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Enhanced photocatalytic hydrogen evolution of?CdWO4 through polar organic molecule modification
摘要： In this work, a polar molecule 4-mercaptobenzoic acid (4-MBA) is anchored on the surface of CdWO4 by forming CdeS and WeS bond. Photocatalytic hydrogen evolution is significantly enhanced (about 3.41 times) after the modification. The reason is due to the modification of 4-MBA, which results in a polar surface and built-in electric field. The polar surface is confirmed by the steady state and time-resolved PL spectra, Voc and SHG results.
关键词： CdWO4,Photocatalytic hydrogen evolution,4-mercaptobenzoic acid,Surface modification,Built-in electric field
更新于2025-09-19 17:15:36
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European Microscopy Congress 2016: Proceedings || An in-situ Low Energy Argon Ion Source for Local Surface Modification
摘要： A new in-situ low energy ion source for surface modification of a sample surface has been designed. The source is based on the principle of low energy ion bombardment from a beam of ions such as Ar+, N+, or He+ can be used for a local modification of the sample surface. Typical energies are in the range 10 - 100 eV, covering the interaction types from chemical reaction to ion etching and to ion implantation. The source is based on the following principle: electrons from a filament are accelerated towards a grid by a potential difference between the filament and the grid. The electrons enter a gas-filled region between the grid and the sample, where they ionize the gas. The ions are then accelerated towards the sample by a potential difference between the grid and the sample. The source produces a static beam of ions with a selectable energy of 10-100 eV and a full width half maximum (FWHM) of 7.1 um. This corresponds to a central ion current density of 0.019 nA/um2 at 100 eV, which is very similar to the current density at 100 eV of a regular ICP source. In this way, the sample area that is affected by the low energy ions can be more or less defined by the applied bias voltage. The first application can be polishing the top surface of a TMD laminate produced by CVD, or improvement of and LPE surface prepared by ICP. An example of the interaction with the beam is shown in Figure 1, where a native oxide on Si has been removed in 25 seconds, using 100 eV Ar+ ions.
关键词： Ar+,surface modification,low energy ion source,chemical reaction,FWHM,native oxide removal,ion etching,ICP,current density,static beam,N+,ion bombardment,TMD,He+,LPE,ion implantation,in-situ,gas ionization,filament,grid,CVD
更新于2025-09-19 17:15:36
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Fiber Laser || Laser Surface Modification — A Focus on the Wear Degradation of Titanium Alloy
摘要： Over the years, engineering materials are being developed due to the need for better service performance. Wear, a common phenomenon in applications requiring surface interaction, leads to catastrophic failure of materials in the industry. Hence, preventing this form of degradation requires the selection of an appropriate surface modification technique. Laser surface modification techniques have been established by researchers to improve mechanical and tribological properties of materials. In this chapter, adequate knowledge about laser surface cladding and its processing parameters coupled with the oxidation, wear and corrosion performances of laser-modified titanium has been reviewed.
关键词： Titanium,Laser surface cladding,Wear,Surface modification technique
更新于2025-09-19 17:13:59
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Freeze‐Facilitated Ligand Binding to Plasmonic Gold Nanorods
摘要： Gold nanorods (AuNRs) are an important class of advanced plasmonic materials, but unlike gold nanospheres (AuNSs) their surface modification is difficult due to the specific surfactant layer of cetyltrimethylammonium bromide (CTAB) resulted from the synthesis. In this paper, a freeze-induced surface modification strategy is proposed for AuNRs. Freezing AuNRs right after a simple wash step can facilitate binding of surface ligands and allow assembly of functional biointerface in a fast time scale. This strategy is simple, fast, versatile, and robust, allowing attachments of different ligand molecules, including organic dyes, poly(ethylene glycol)s (PEGs), and DNAs onto AuNRs without additional reagent. An optimal condition for DNA loading is determined with a matrix driven approach. It is shown that the attached ligand molecules are functional, allowing formation of core–satellite type structures using DNAs linking to AuNSs, or high-density vertical superlattice arrays using PEGylated AuNRs.
关键词： DNA,surface modification,gold nanorods,surface ligands
更新于2025-09-19 17:13:59
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Surface modification induced by perovskite quantum dots for triple-cation perovskite solar cells
摘要： Organic-inorganic hybrid perovskite solar cells are regarded as the most promising new-generation photovoltaic technology, owing to their high power conversion efficiencies and low cost. However, surface imperfections of perovskite films impede improvement in device performances, since surface imperfections can introduce undesired energy losses under sunlight illumination. Here, we show that the incorporation of zero-dimensional perovskite quantum dots into three-dimensional perovskite films can heal surface imperfections in perovskite films. Introducing perovskite quantum dots also leads to a more uniform surface topography and potential, along with an improved crystal quality of the triple-cation perovskite films, benefiting charge carrier kinetics between the perovskite films and the charge extraction layers. Ultimately, we achieve a power conversion efficiency exceeding 21% in triple-cation perovskite solar cells.
关键词： quantum dots,surface modification,perovskite solar cells,high efficiency
更新于2025-09-19 17:13:59