纳米球刻蚀技术

纳米球刻蚀技术是一种并行的制备纳米点阵的自组装方法,其核心是二维有序纳米胶体球阵列掩膜的制备。本文详细介绍了二维有序纳米胶体球阵列掩膜的各种自组装合成原理与方法,分析了各种工艺参数的纳米阵列的影响。最后,综述了纳米球刻蚀技术的发展状况与趋势。     

Nanosphere lithography from template-directed colloidal sphere assemblies

Conventional nanosphere lithography holds the drawbacks of lacking precise control over the shape and architecture of the resultant nanostructures. In this work, nanoimprinting lithography was used to construct various desired patterns on a polymer film coated on a silicon substrate. The patterns were then used as templates to direct the self-assembly of silica colloidal spheres, forming colloidal assemblies with well-controlled sizes, shapes, and structures. Subsequent nanosphere lithography using template-directed colloidal sphere assemblies resulted in complex nanostructures that can not be obtained using the conventional nanosphere lithography method.     

Nanosphere and carbon nanotube as motor and gun controlled by light

We propose a system like motor and gun molecular that has the open extremities of external nanotube using the internal C60 nanosphere as a probe. The system consists of a rigid and static nanotube opened and the internal C60 probe that allows relaxation between them. The initial position of C60 is out of symmetry that permits the probe to start the system movement due to van der Waals force acting in the probe. The simulation was made by classic molecular dynamics with standard parameterization. We calculated thermodynamics properties of these two devices as molar specific heat and molar entropy variation. Properties as probe speed were obtained like molecular motor and gun versus time. The nanotube has 360 carbon atoms with up to almost 0.7 ns of simulation. These facts can be useful for building new molecular machines.     

Fluorophore-Decorated Mie Resonant Silicon Nanosphere for Scattering/Fluorescence Dual-Mode Imaging

Inorganic nanoparticles with multiple functions have been attracting attention as multimodal nanoprobes in bioimaging, biomolecule detection, and medical diagnosis and treatment. A drawback of conventional metallic nanoparticle-based nanoprobes is the Ohmic losses that lead to fluorescence quenching of attached molecules and local heating under light irradiation. Here, metal-free nanoprobes capable of scattering/fluorescence dual-mode imaging are developed. The nanoprobes are composed of a silicon nanosphere core having efficient Mie scattering in the visible to near infrared range and a fluorophore doped silica shell. The dark-field scattering and photoluminescence images/spectra for nanoprobes made from different size silicon nanospheres and different kinds of fluorophores are studied by single particle spectroscopy. The fluorescence spectra are strongly modified by the Mie modes of a silicon nanosphere core. By comparing scattering and fluorescence spectra and calculated Purcell factors, the fluorescence enhancement factor is quantitatively discussed. In vitro scattering/fluorescence imaging studies on human cancer cells demonstrate that the developed nanoparticles work as scattering/fluorescence dual-mode imaging nanoprobes.     

Nanosphere monolayer-templated, ion-assisted nanofeature etching in dielectric materials: a numerical simulation of nanoscale ion flux topography

The results of numerical simulations of nanometer precision distributions of microscopic ion fluxes in ion-assisted etching of nanoscale features on the surfaces of dielectric materials using a self-assembled monolayer of spherical nanoparticles as a mask are presented. It is shown that the ion fluxes to the substrate and nanosphere surfaces can be effectively controlled by the plasma parameters and the external bias applied to the substrate. By proper adjustment of these parameters, the ion flux can be focused onto the areas uncovered by the nanospheres. Under certain conditions, the ion flux distributions feature sophisticated hexagonal patterns, which may lead to very different nanofeature etching profiles. The results presented are generic and suggest viable ways to overcome some of the limitations of the existing plasma-assisted nanolithography.     

Plasmonic Cyclic Au Nanosphere Hexamers (Small 7/2023)

Rational design of plasmonic colloidal assemblies via bottom-up synthesis is challenging but would show unprecedented optical properties that strongly relate to the assembly's shape and spatial arrangement. Herein, the synthesis of plasmonic cyclic Au nanosphere hexamers (PCHs) is reported, wherein six Au nanospheres (Au NSs) are connected via thin metal ligaments. By tuning Au reduction, six dangling Au NSs are interconnected with a core hexagon nanoplate (NPL). Then, Pt atoms are selectively deposited on the edges of the spheres. After etching of the core, necklace-like nanostructures of Pt framework are obtained. Deposition of Au is followed, leading to PCHs in high yield (≈90%). Notably, PCHs exhibit the combinatorial plasmonic characteristics of individual Au NSs and the in-plane coupling of the six linked Au NSs. They yield highly uniform, reproducible, and polarization-independent single-particle surface-enhanced Raman scattering signals, which are attributed to the 2-dimensional isotropic alignment of the Au NSs. Those are applied to a SERS-based immunoassay as quantitative and qualitative single particle SERS nanoprobes. This assay shows a low limit-of-detection, down to 100 pm , which is orders of magnitude lower than those based on Au NSs, and one order of magnitude lower than an assay using analogous particles of smooth Au nanorings.     

Palladium‐Decorated Silicon Nanomesh Fabricated by Nanosphere Lithography for High Performance,Room Temperature Hydrogen Sensing

A hydrogen (H₂) gas sensor based on a silicon (Si) nanomesh structure decorated with palladium (Pd) nanoparticles is fabricated via polystyrene nanosphere lithography and top‐down fabrication processes. The gas sensor shows dramatically improved H₂ gas sensitivity compared with an Si thin film sensor without nanopatterns. Furthermore, a buffered oxide etchant treatment of the Si nanomesh structure results in an additional performance improvement. The final sensor device shows fast H₂ response and high selectivity to H₂ gas among other gases. The sensing performance is stable and shows repeatable responses in both dry and high humidity ambient environments. The sensor also shows high stability without noticeable performance degradation after one month. This approach allows the facile fabrication of high performance H₂ sensors via a cost‐effective, complementary metal–oxide–semiconductor (CMOS) compatible, and scalable nanopatterning method.     

模板法制备无机纳米中空球的研究进展

近年来,无机纳米中空球由于其独特的结构特点,表现出普通材料不具备的性能,引起研究者广泛的兴趣.阐述了当前模板法合成无机纳米中空球材料的研究现状包括合成方法、合成现状及机理,并提出当前无机中空球合成存在问题及展望.希望有关无机中空球材料的研究能够不断完善,发挥其潜在的应用价值.     

Nanosphere molecularly imprinted polymers doped with gold nanoparticles for high selectivity molecular sensors

We report the first attempt of using molecularly imprinted polymers (MIPs) in the shape of nanoparticles that were doped with gold nanoparticles (AuNPs) for surface enhanced Raman scattering (SERS)-based sensing of molecular species.Specifically,AuNPs doped molecularly imprinted nano-spheres (AuNPs@nanoMIPs) were synthesized by one-pot precipitation polymerization using Sudan Ⅳ as the template for the SERS sensing.The AuNPs@nanoMIPs were characterized by various modes of scanning transmission electron microscopy (STEM) that showed the exact location of the AuNPs inside the MIP particles.The effects of Au concentration and solution stirring on the shape and the polydispersity of the particles were studied.Significant enhancement of the Raman signals was observed only when the MIP particles were doped with the AuNPs.The SERS signal improved significantly with increase in the Au concentration inside the AuNPs@nanoMIPs.Selectivity measurements of the Sudan Ⅳ imprinted AuNPs@nanoMIPs carried out with different Sudan derivatives showed high selectivity of the AuNPs-doped MIP particles.     

Hollow Pd/MOF Nanosphere with Double Shells as Multifunctional Catalyst for Hydrogenation Reaction

A new type of hollow nanostructure featured double metal‐organic frameworks shells with metal nanoparticles (MNPs) is designed and fabricated by the methods of ship in a bottle and bottle around the ship. The nanostructure material, hereinafter denoted as Void@HKUST‐1/Pd@ZIF‐8, is confirmed by the analyses of photograph, transmission electron microscopy, scanning electron microscopy, powder X‐ray diffraction, inductively coupled plasma, and N₂ sorption. It possesses various multifunctionally structural characteristics such as hollow cavity which can improve mass transfer, the adjacent of the inner HKUST‐1 shell to the void which enables the matrix of the shell to host and well disperse MNPs, and an outer ZIF‐8 shell which acts as protective layer against the leaching of MNPs and a sieve to guarantee molecular‐size selectivity. This makes the material eligible candidates for the heterogeneous catalyst. As a proof of concept, the liquid‐phase hydrogenation of olefins with different molecular sizes as a model reaction is employed. It demonstrates the efficient catalytic activity and size‐selectivity of Void@HKUST‐1/Pd@ZIF‐8.